Proceedings Volume 5253

Fifth International Symposium on Instrumentation and Control Technology

Guangjun Zhang, Huijie Zhao, Zhongyu Wang
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Proceedings Volume 5253

Fifth International Symposium on Instrumentation and Control Technology

Guangjun Zhang, Huijie Zhao, Zhongyu Wang
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 2 September 2003
Contents: 9 Sessions, 213 Papers, 0 Presentations
Conference: Fifth International Symposium on Instrumentation and Control Technology 2003
Volume Number: 5253

Table of Contents

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Table of Contents

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  • Sensors and Instrumentation
  • Signal Acquisition, Processing, and Analysis
  • Measurement Theory and Technique
  • Photoelectronic Technology and Instruments
  • Automatic Measurement, Control, Bus, and Network
  • Control Theory and Automation I
  • Control Theory and Automation II
  • Modeling and Simulation
  • Artificial Intelligence and Fault Detection
Sensors and Instrumentation
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Dynamic calibration methods for transducers of both ultrahigh and ultralow temperature
Jun-Qin Huang
The dynamic calibration methods for both transducers of ultra high and ultra low temperature are presented in this paper. The dynamic calibration methods for general temperature transducers are already fully discussed in the references. The dynamic calibrations of following transducers are fully discussed in the references: force, acceleration, angular speed (gyroscop), pressure, temperature, angle of attack, resonant vibration pressure transducer, many kinds of servo transducer, etc. The dynamic excitation signal generators of different kinds of transducers are quite different in the dynamic calibration systems, but the other parts of the dynamic calibration systems are very similar, e.g. The data acquisition and recording equipment of the dynamic responsed signal of calibrated transducers. So, the dynamic excitation signal generators of both transducers of ultra high and ultra low temperatures and the block diagrams of dynamic calibration systems are presented in this paper. Finally, some discussions of the dynamic excitation signal generators of different kinds of the temperature transducers are given.
Attitude manipulation analysis of microsphere
Baiwei Guo, Darong Chen, Jiadao Wang
With the development of micro sensors, micro actuators and micro components, Micro Electro Mechanical Systems (MEMS) have been researched more and more widely. Micro manipulation is the key technique to assembly and test MEMS. The previous researches show that the dominant mechanisms are not gravity but van der Waals, electrostatic and capillary forces. Many works focused on developing varied methods of manipulation that could grip or release micro objects by utilizing these micro forces or reducing them. In order to achieve complex manipulation, a simple attitude manipulation (rolling manipulation and spinning manipulation) method for micro spheres is analyzed in this paper. The models include the interactions among micro objects such as van der Waals and elastic contact forces. The results of the models show the great influence of van der Waals force on the manipulation and provide relevant evidence to the manipulation control.
A brief introduction to theapplication of the fiber optic sensor to aeroengine
Guanbing Cheng, Shuming Li, Jie Bai
The paper introduces briefly the characteristics of the fiber-optic sensor and the principle of transmission. According to its own advantage over traditional sensors, several kinds of the optical fiber sensors here mentioned will be applied to measure the items such as temperature displacement, stress and so on. In the meanwhile the article also introduces the latest application on the aero-engines. For example the paper will illuminate that the infrared frequency charts can achieve temperature and then mention the concerned system check up the blades when the aero-engine is in operation. Eventually it will introduce the situation of development of the fiber-optic sensor and have a trend for the integration, intelligence and automation.
Simulation of silicon micromachined ultrasonic transducers
Li-Feng Ge
A general 3-D TDK model developed further in this paper has been successfully applied to simulate a surface micromachined electrostatic or capacitive ultrasonic transducer with vacuum-sealed air-cavities (i.e. cMUT). Also, the paper gives a reliable prediction of resonant and anti-resonant frequencies of a typical cMUT.
A new and effective type of air-medium ultrasonic sensor
Zhimin Ma, Xiaohong Zhao, Shao Zhang, et al.
The vibration modes of air-medium ultrasonic sensor with a multi-vibration disc and the counteraction effect of the two phase-reversal regions of the disc are analyzed in this paper. A new air-medium type of ultrasonic sensor, with a resonant air gap of λ/2, is proposed. The operation theory and the experimental results of the sensor are also presented.
Study on lateral dual-element electron tunneling accelerometer
Yuhe Li, Qingxiang Li, Zhifeng Long, et al.
Electron tunneling accelerometer has the advantages of high precision, small volume, low consumption and so on. This paper introduces the design on a lateral dual-element Electron Tunneling Accelerometer. The model, structure design, parameters test and fabrication process are provided in detail. The results of analysis and simulation show that the working frequency of sensor could be up to 2 kHz.
Analysis and design of an electrostatic space accelerometer
Qiuping Wu, Zhongyu Gao, Yongliang Wang
In order to eliminate the non-gravitational effects in the accurate determination of the orbit and determine the higher harmonics of the Earth's gravity potential, an electrostatic space accelerometer is being developed for these space applications, exhibiting a much lower bias and a high resolution, a hundred times better than the accelerometer used in aircraft for inertial navigation. The electrostatic space accelerometer operation is based on the electrostatic suspension of an inertial proof mass. The servo-control is fed with the position of the proof mass and generates through drive voltage amplifiers, voltage differences that exert the necessary force on the proof mass to maintain it motionless with respect to the frame. The frame's acceleration is proportional to the force opposing to the motion of the proof mass. The results of the simulations and experiments validate the feasibility of the levitation concept and meet the expectations of the future gravitational field measurement from low Earth orbit satellites.
Virtual instrument for calibrating of multisensor testing system based on LabWindows/CVI
Xiaojun T. Tang, Weiping Li, Junhua Liu
In multi-sensor multi-parameter testing system, the mapping relation between inputs and outputs of the system must be built with calibrating data. In this paper, typical methods used to build this mapping relation are gathered and embed in a virtual instrument based on LabWindows/CVI. After data fusion has finished, instrument reports the fusion result to user. This made what user need to do are adding the path of file, in which calibrating data is saved, and choosing data fusion method, but not deep-seated understanding to data fusion methods. So repetitive development about data fusion can be avoided, the applying of data fusion can be broadened, and the development process of multi-sensor system can be accelerated.
Soft-sensing technique based on extension method
Bin He, Xuefeng Zhu
In soft-sensing technique, much attention has paid to the evaluation and optimization of secondary variables. But little attention has been paid to the problem how to choose suitable secondary variables, which is still open and seems difficult. Based on extension methods, which study the laws for opening-up things and solving incompatible problems, the paper presents a new kind of inferential estimator called extension inferential estimator, which integrates the routine inferential estimator with an extension regulator. In the extension inferential estimator, five extension methods for choosing secondary variables are developed: (1) to consider the measurement object and its transformation; (2) to consider the characteristic and its transformation; (3) to consider the measure and its transformation; (4) to consider the measurement principle or method and its transformation; (5) to consider the measurement tool or component and its transformation.
New technique for the stability of the zero point of catalytic sensor
Minming Tong
The zero-point drift of catalytic sensor could increase the error of detecting methane in mine. The high stability of the zero-point drift of the sensor is very important for the reliability. The catalytic sensor is made of detecting component and compensating component and the consistency of the two components is related to the stability of the sensor. The new matching technique of compensating component and detecting component, the process of dynamic parameters, could much improve the zero-point stability of the catalytic sensor.
Ellipse fitting of short light stripe for structured-light-based 2D vision inspection
Guangjun Zhang, Zhenzhong Wei
Structured light based 3D vision has wide applications in inspecting the form and position errors like straightness and coaxiality of cylindrical workpieces. But for these applications, the light stripe on the workpiece's surface is much too short, and contains inadequate data information, even with some noise. Under such circumstances, the ellipse fitting to the scattered data of the light stripe is not efficient enough, and its fitting accuracy is usually poor. To address this problem, a new least-square fitting method based on the constraint of ellipse minor axis (called CEMA method) is proposed in detail in this paper. Simulations are given for the proposed method and for five other popular methods described in the literature. The results show that the proposed method can efficiently improve the accuracy and the robustness of ellipse fitting to the scattered data of short light stripe.
Highaccuracy real-time heat meter for heat supply system
Tianying Cheng, Jian Wang
The dedicated heat meter is used for each unit of heat-supply system. It can measure and add up the consumed energy of every unit by MCU system, control status of the heat-supply system by the self-holding electromagnetic valve and transmit all the data to personal computer to create users' database by communication controller. The principle and design method of heat meter are introduced in this paper.
Design and realization of a measuring system for electronic photoelectric combined current/voltage sensors
Zheng Qian, Zhu Shen, Chengmu Luo
Electronic transformers instead of electro-magnetic transformers are the developing trend. But it is still difficult for electronic transformers to put into practice because the influence of temperature and the stability of long-term operation. In this paper, an electronic combined transformer is presented. In order to obtain the steady long-term operation results, the mature sensor design technology is adopted. And then the circuit part of measuring system is designed and realized. The measuring results made in Lab show that the error of circuit part in measuring system is lower than that of 0.5 class transformer. The on-site measurement is processed at last. These testing results and corresponding analysis will be helpful for the improvement of the whole testing system.
Detection on the target falling range by using intersection measuring of stereo vision
Yujia Pang, Xiangjun Wang
The method of intersection measuring of stereo vision is adopted to detect the target falling range. By computing the system error and the random error, it is verified that by using this method the precision of detecting the falling target range can be controlled within ± 1m in the range of 1 km.
Evaluating the anisotropy of 3D rough surface based on angular spectral moment
Chenggui Li
The analyses of two-dimensional power spectrums of engineering surfaces are effective and valuable for 3D surface characterization. The past theoretical analyses and experimental results have proved that the areal Fourier spectrum analysis and spectral moments can be both used to describe the surface texture, especially for the directionality of surface. In this paper, the computing procedures of angular spectrum and the second order spectral moment are first introduced, and the angular spectrum moment has been used to evaluate the anisotropy of 3D rough surface. Then by analyzing some typical samples machined by various techniques, such as fine faced-turned, precision ground, lapping, electric discharge machining etc., the paper investigates the directional differences on the surfaces by the angular spectral analysis techniques. And some relational issues about this aspect are also discussed.
Mathematical model of low-frequency electromagnetic horizontal vibration platform
Xiaolei Li, Shangchun Fan
In this paper, the mathematical model of low frequency electromagnetic vibration platform is established on the basis of its mechanical structure and electrical structure. Its frequency response characteristics are also analyzed in detail. The correctness of the mathematical model is verified by a lot of testing data. Subsequently, nonlinear factors of the vibration platform are discussed, including magnetic field's nonlinear, moving-coil response and nonlinear output of power amplifiers, and so on. These factors lead to a lot of harmonic vibration and severe vibration waveform distortion. Some measures to decrease the magnetic field's nonlinear and the effect of moving-coil response are proposed for the low frequency electromagnetic vibration platform.
Implementation of a novel pulsed ultrasonic Doppler velocity profiler
Shounan Luo, Yan Liu, Guanping Feng
The objective of the work is to apply advanced digital signal processing (DSP) and pulsed Doppler echography techniques to analyze velocity profile of the measured fluid in a closed full-pipe. In order to reliably measure velocity profile where non-intrusive ultrasonic Doppler velocity profilers (UDVPs) cannot properly transmit and receive ultrasonic signals, a single-crystal transducer was inserted directly into the fluid stream. Then ultrasonic signals were transmitted and received based on the pulsed Doppler echography theory. A modified covariance (MCOV) estimator and a TMS320VC5410 DSP chip with a high-speed up to 160 MIPS were employed to analyze spectrum of the software-gated echo signals. Finally, computer simulations were also presented to demonstrate effectiveness of the novel UDVP. Results indicate that this instrument is particularly effective in terms of velocity profiling and can be widely applied for flow measurement and fluid dynamics research.
Error study and application of capacitive displacement sensor based instrument for measuring welded joint angularity and stagger joint
Xiushui Ma, Kejun Xu, Baosheng Yang, et al.
In order to ensure the operating security of pressure containers, the welded joint angularity and stagger joint must be checked. The object of our studying in this paper is the instrument we have developed for measuring the welded joint angularity and stagger joint based on the capacitive displacement sensor. Though the analyses of error factors in design, manufacture and operating, such as principle error, the capacitive sensor error, the manufacture error of mechanical scales, the assemble error, the operating error. A method of reducing errors and increasing precision of the products has been posed, and has found ready application in practice.
PCI-based real-time image acquisition system for medical electronic endoscope
Jie Jiang, Guangjun Zhang, Daoyin Yu, et al.
The paper introduces a high speed image acquisition system for medical Electronic Endoscope based on PCI bus. The popular PCI controller-AMCC S5933 is utilized to implement PCI bus interface. FPGA is applied to control the data transferring and implement S5933 ADD_ON interface. The device driver of Windows is developed based on WinDriver. The experiment results show that the frequency of image acquisition can reach 33 MHz and the frame rate can be up to 50 fps at 800x600.
Aircraft fuel density measurement based on radioactive ray attenuation principle
Nan Li, Jun-fang Lv
Based on the high precision and digital-measuring requirements for aircraft fuel density measurement which the aircraft Fuel Quantity Indication System (FIQS) has proposed, this paper introduced the Radioactive Rays Attenuation Principle and discussed its specific realization on real-time measurement of aircraft fuel density with high precision.
Mobile workstation for in-site synthesis calibration
RuiXian Zhao, XiaoFeng Meng
A mobile workstation for in-site synthesis calibration including vehicle system and universal synthesis calibration platform is described in this paper. The vehicle system supplies the transportation ability and provides the environment of in-site calibration. The universal synthesis calibration platform with the improved capability of redesign and expansion, can synthetically calibrate many kinds of synthetic testing instruments. In order to catch the goals above, the framework, designing methods and measuring value transfer of the platform is discussed in this paper. The mobile workstation has made itinerant measurement for many kinds of synthetic testing instruments possible. It does not only solve the problem of on-line calibration of bulky synthetic testing instruments in the field, but also improve the efficiency and profit of the current measurement.
Design of a multifunctional and portable detector for indoor gases
Liping Zhang, Yutian Wang, Taishan Li
With the increase of the living standards of city dwellers, home decoration has been more and more popular these years. Different kinds of material have come into people's home, which brings about beauties to the house as well as some bad effect. Because of differences in manufacturing techniques and quality, much of the material will emit poisonous gases more or less. Even if you have selected the qualified product, the toal amount of gases in you houses may not be guaranteed because of the simple reason that more than one kind of material are applied. Living in the complex environment for a long time will eventually have a bad effect on one's health. In addition the fear of the harm to be done will exert great impact psychologically. In another aspect, the coal-gas in the house-hood for cooking is also explosive and poisonous. In conclusion, the research on the indoor hazardous gases measurement and alarm device is of much economic and practical importance. The device is portable and versatile. We use rechargeable battery as the power supply. The device can detect the density of gases at the ppb level for the emission of the material and the measured value can be shown on the display. As for coal gas it can detect the percentage of LEL and make sound of alarm. We use two kinds of gas-sensors in the device, with catalytic combustion principal for coal gas detection and the PID method for the gas emissions of the decoration material. UV will destroy harmful material (such as: ammonia, dimethylamine, methyl-sulfhydrate, benzene etc.) into positive or negative ions. The sensor detects the electric charges of ionized gases and converts them into electric current signals. It is then amplified and changed into digits by amplifier and A/D. The digit signal is processed by micro-controller system of the device.
Three-dimensional space equivalent transform principle and tentative design of capacitive displacement transducer with 10-nm resolution
Zengyao Zhang, Hao Zhang
From principle of capacitive displacement transducer of phase modulation main problems that may be appeared in the measurement system with 10 nm resolution are analyzed. First one-one corresponding relation among pitch W of spatial field of scale electrodes, time period T and phase shift ω of the output signal is introduced. Thereby the theoretical foundation through reducing planar geometrical figure of the transducer to increase resolution is established. The three-dimensional equivalent transform principle and other methods are further put forward to scatter the dense figure and reduce machining difficulties. The principle also could be used for some other grating transducer. Then the scheme resolving lead wire problem is given. Present technology machining electrodes is explained. Better Micro Electro Mechanical System (MEMs) technology is indicated. But above method is insufficient to get 10 nm resolution. So PLL is given, which could achieve higher subdivision number. The scheme with 10 nm resolution will be more perfectly realized through above-mentioned three aspects. Finally it is introduced that the transducer technique is transplanted to grating. Higher resolution is expected by use of Micro Optical Electro Mechanical System (MOEMS) and grating to get smaller pitch to further resolve the design problems of the transducer with nm resolution.
Application of one multimode fiber optical sensor in optical tomography technology
Zhiwei Shi, Yang Li, Hua Zhou, et al.
Optical tomography technique is very important in changing conventional techniques for the development of imaging science. It will be applied widely in the fields of biomedical imaging, material structure analyzing and blurry martial target distinguishing etc. In this paper, we introduce the application of a multimode optical fiber sensor in tomography technology. Optic fiber with polished terminations requires the incident ray within a certain angle, so it usually causes deficiency of the light power entered into the optical fiber and diffuse the emergent ray, so polished terminations make it difficult to receive and detect the emergent rays. In order to solve the two problems above, a sphere lens is designed for one termination and a cylinder lens is designed for the other termination. This paper uses mathematics to analyze the relationship between the sphere lens radius, the cylinder lens radius, refractive index of the optical fiber. The relationship between the scanning angles and the numbers of the numbers of the received optical fiber is researched in the air medium, and the designing method for the sphere lens and the cylinder lens are present.
New method for automatically measuring geometric parameters of wheel sets by laser
Qibo Feng, Shinqian Chen
How to automatically and effectively measure geometric parameters and defects of train wheel-sets is a key problem in the maintenance of wheelsets. Currently, there are several methods for this kind of measurements. However, all these methods cannot meet the requirements of high accuracy, low cost, and short measurement periods at the same time. A quite simple and novel method for measuring geometric parameters and defects of wheelsets was proposed in this paper. Most key geometric parameters, such as diameters at any given point of the tread, flange thickness, flange height, rim thickness, rim width, wheel flats, and distance between internal faces etc., can be easily obtained by use of five sets of parallelogram mechanisms together with laser transducers. Wheel-sets are dragged simply by a chain to pass through the measurement system when the measurement results are done, which has totally changed the situation that a measurement platform was required to support a wheelset and makes it rotate in order to take measurements. Methods to calibrate the measurement errors of the system are also discussed, and some in-situ measurement results are given. Experimental results show that the measurement uncertainty within 0.1 mm can be reached by the developed system.
Micromachined resonant gyroscope
Anping Qiu, Shourong Wang, Bailing Zhou
Resonant sensing has a number of advantages, including simpler dynamics and control, improved stability, large dynamic range, high resolution, and a quasidigital FM output. Resonant sensing is attractive in micromachined gyroscope application. In this paper, we present a new micromachined resonant gyroscope and briefly introduce the basic operating principle. The double-ended tuning fork (DETF) is an important element in DETF resonator. A theoretical treatment starting from a classical theory for Bernoulli-Euler beams to modal the operation of DETF is given. T The relation between the frequency shift and the applied force is also built. The simulation and the relation of the frequency shift and the applied force by the finite element analysis (FEA) are presented. The conclusion is that analytical analysis results are very close to the simulation results by FEA. Thus, usefulness of the analytical analysis results may be more efficient for our design of micromachined resonant gyroscopes.
Imprint structured organic thin film transistors as driving circuit in single-use sensor applications
U. Hilleringmann, C. Pannemann
Organic thin film transistors on silicon substrate are fabricated by standard lithography techniques to get transistors with micrometer scale gate length. The semiconducting layer consists of the evaporated organic molecule Pentacene. Transistor parameters taken from transistors with channel lengths of 10 μm - 1 μm confirm the validity of the models for silicon MOS transistors. For further reduction in channel length the imprint technique is proposed to integrate sub micron distances between the drain and source metallization of the transistor.
Large-area definition of nano-electrodes by nanoimprint lithography
Matthias Wissen, Hella-Christin Scheer, Hubert Schulz, et al.
Sidewall lithography was used as a low cost fabrication process for high aspect ratio stamps for hot embossing. The stamps, featuring up to 1 μm pattern height and an aspect ratio of about 5:1 were tested in a typical hot embossing process at 50 bar. Mechanical stability of the crystalline stamp structures was achieved after optimization of the respective dry etch process. At imprint temperatures of 140°C PMMA was imprinted over areas of four inch diameter. After residual layer removal in the trenches Al electrodes of 500 nm height and 200 nm width could be defined by evaporation and lift off.
Signal Acquisition, Processing, and Analysis
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Optimal strategy for digital signal parallel processing
Zhengxiang Qian, Lizhi Qian, Liang Tang, et al.
This paper studies the parallel processing algorithms of digital signal linear prediction, especially in speech signals and image signals. An autoregressive digital signal vector series with stable covariance can be obtained by grouping adjacent samples of signal source series and a strategy for vector predictive coding with highly parallel processing ability can be achieved by applying the principle of orthogonal projection in Hilbert space. Then an adaptive parallel processing algorithms for digital signal linear prediction can be given. Compared with traditional lattice methods, the algorithms have an obvious progress in the computation complexity and storage. Finally its performance is tested by computer simulation.
Application of image recognition in GIS
Kaiyu Xu, Zhijing Xu, Huayao Zheng
In view of the existing issues on extraction of GIS vector data from maps, we propose an image recognition method based on wavelet transformation. Using the method, we first made the wavelet transformation of a color urban traffic map and took the value near zero points of the wavelet coefficient, and then, color model transformation was adopted to obtain a gray image. Afterwards, an appropriate threshold was chosen and the gray image was transformed into a bilevel image. In the end, the erosion algorithm in the mathematical morphology was used to thin the image in order to identify the road information. The experimental result showed that the method could be used to effectively identify the road information from an urban traffic map.
Speech feature extracting based on DSP
Jingtao Niu, Zhongke Shi
In this paper, for the voiced frame in the speech processing, the implementations of LPC prognosticate coefficient resolution by Levisohn-Durbin algorithm on the DSP based system was proposed, and also the implementation of L. R. Rabiner basic frequency estimation is discussed. At the end of this paper, several new methods of sound feature extraction only by voiced frame is also discussed.
Performance analysis of the LMS Fourier analyzer in the presence of frequency mismatch
Yegui Xiao, Akira Ikuta, Liying Ma
The statistical performances of the conventional adaptive Fourier analyzers, such as the LMS, the RLS algorithms and so on, may degenerate significantly, if the signal frequencies given to the analyzers differ from the true signal frequencies. This difference is referred to as frequency mismatch (FM). In this paper, we analyze extensively the performance of the conventional LMS Fourier analyzer in the presence of FM. We derive its dynamics and steady-state properties in detail. The optimum step size parameters which minimize the influence of the FM are also derived. Simulations are performed to reveal the validity of the analytical findings.
Miniaturization of the atmospheric laser communication APT system
Wei Sun, Yong Ai, Jinling Yang, et al.
The paper presents a scheme of the miniaturization of APT system and the design of the system based on the investigation of status in quo. It deals with the infrared image of the other terminal's beacon from the Charge Coupled Device (CCD) by the Complex Programmable Logic Device (CPLD). The result of the transaction is delivered to Single Chip Microcomputer (SCM), which controls the micro-servomotor. Subsequently, the precision drive system drives the optical system that uses only one light axis for signal beam and beacon to finish the acquisition, pointing, and tracking of the communication terminals. The anlayses of the APT system's error indicate that the tracking error limits in 70uRad with the weight of the system lighter than 8-kilogram.
Wavelet-based online disturbance monitoring for local power system
Xianyong Xiao, Jinding He, Honggeng Yang
Industries with sensitive electrical loads are becoming more and more dependent on the quality of local power system. The quality of a power supply is largely synonymous with the voltage quality for the power system. The general strategy to assure voltage quality and sound operation of a sensitive load is to monitor the supply voltage and take appropriate countermeasures based on detection of voltage disturbance that exceed the load tolerance limits. So rapid monitoring and identifying the voltage disturbance are desired features for power quality enhancement. This paper introduces a new on-line power quality disturbance monitoring approach based on wavelet transform. This approach can identify voltage disturbances and discriminates the type of event that has result in the voltage disturbance. The proposed approach is significantly and more precise in discriminating the type of transient event than conventional voltage-based disturbance detection approaches. Feasibility of the proposed approach is demonstrated based on the monitoring of an actual local power system in Sichuan province of China.
New robust filter for uncertain discrete-time system
Zhongke Shi
A two-step robust filtering algorithm for uncertain discrete-time system is presented. To get a series of computational equations, the upper bound of uncertain parts generated by uncertain systematic matrix in the expression of the error covariance matrix of state estimation is given and the equivalent systematic matrix is obtained. These results build up a robust time update algorithm. On the other hand, the lower bound of uncertain parts generated by uncertain observation matrix in the expression of the error covariance matrix of state estimation is given and the equivalent observation matrix is obtained. Thus both the time update and measurement update algorithms are suggested. By means of matrix inversion formula, the expression structures of both time update and measurement update algorithms are all simplified.
Combining blur and affine moment invariants in object recognition
Yingchun Li, Hexin Chen, Jiujun Zhang, et al.
In many application areas such as military photointerpretation and remote sensing, images are usually subjected to geometric distortion and blur degradation. The determination of invariant characteristics is an important problem in pattern recognition. In this paper, an approach to derive blur and affine combined invariants is presented to recognize the objects. As we prove in the paper, they can be constructed by combining affine moment invariants and blur invariants derived earlier. The tests show that combined invariants can recognize objects in the degraded image without any restoration and geometric normalization.
Singularity recognization of vibration signal based on Hermitian wavelet for diagnosis
Yanyang Zi, Qingxiang Li, Zhengjia He
The vibration signal in the nature of singularity is always caused by mechanical fault of equipment. It is important to recognize the signal singularity correctly for mechanical fault diagnosis. The complex Hermitian wavelet is constructed by means of the first and the second derivatives of the Gaussian function to detect signal signularities. The Hermitian wavelet has a real Fourier transform that will not mix the signal phase with its filter phase, and its real part and imginary part have less oscillation than Morlet wavelet, so that the convolution operation can be process with fewer number of data points and the signal singularity will not be smeared. The time-scale amplitude plot and phase plot based on Hermitian wavelet are presented to detect signal singularities. A successful application has been obtained in diagnosis of large air compressor gearbox. According to the singularities extracted from amplitude plot and phase plot of gearbox vibration signals, it is obvious that there existed impact rub fault that caused intense vibration in the gearbox. After justified maintenance the compressor gearbox runs smoothly in a good condition.
Multiexperiment data processing in identifying model helicopter’s yaw dynamics
Haosheng Chen, Darong Chen
The multi-experiment data is usually needed in identifying a model helicopter's yaw dynamics. In order to strengthen the information of the dynamics and reduce the effect of the noise, a new kind of least square method by using a weighted criterion is investigated to estimate the model parameters. To calculate the factors of the weighted criterion, a neural perceptron is trained to determine the factors automatically. The simulated outputs of the model derived by this kind of method fit the measured outputs well. It is suggested that this kind of data processing method is useful in identifying the yaw dynamics and processing the multi-experiment data for the system identification.
Investigation of blade tip clearance effects in EGT of aeroengine
Xiaogang Ma, Jie Bai, Shuming Li
Exhaust Gas Temperature (EGT) of aero engine is one of pivotal technical indexes, as well as a parameter represents the quality of shop servicing. Factors act on it are complex and incalcuable, but the work presented here concerns the blade tip clearance effects on it. The present study explores that efficiency of modern gas turbines is badly effected by the gaps between rotors an stators; Some literatures reported: efficiency decreases 1.5% when clearance increases 1% length of blade and every 1% efficiency declined it means fuel cost increases 2%. However, the variety of tip clearance is very intricate and difficult to define the change of dynamic tips clearance by theoretic calculation but mainly depend on observation. Data of tip clearance discussed in this paper are static clearance before test and emphasize particularly on investigating the relationship of data of assembling blades and EGT. Besides, BP neural network is adopted in this paper to forecast the effect of tip clearance on EGT.
Implementation of spherical-mirror-based panoramic vision
Peng Wang, Zaili Dong, Maoxiang Sun
Omnidirectional camera is able to obtain 360 degree images of surrounding environment directly. These images contain the abundant information. And this equipment has no any revolver. It is a new scientific research focus of vision techniques. This technology has widely applied prospects in scientific research, community service, industry and military field. In order to get a widely visual scope, curved surface mirror are usually adopted as image collector. Especially the spherical and the hyperbolic mirror are in common. But the observed images were severely distorted (warping). For analyzing and explaining the images correctly, resumption for reconstruction of distorted visual images has to be done. This paper presents the implementation of an omnidirectional camera combining spherical mirror with regular lens. And there are some comparisons of the spherical mirror with the hyperbolic one. The hyperboloid imaged by a standard perspective camera does have a single viewpoint (SVP). But the spheroid imaged by a perspective camera does not have a single viewpoint. This paper settles this drawback by showing how to construct approximately correct single viewpoints in spherical system. This construction is called to be the iso-angle method. Using a mathematical method for approximating a single viewpoint and an iso-angle mapping, a SVP device can be constructed under these conditions. This paper also introduces the principle and structure of omnidirectional camera. In particular, the algorithm of omnidirectional image warping and the experimental results are also discussed.
Comparisons of three methods of PN code acquisition under large Doppler shift
Yunfei Liu, Zhijun Chen, Suli Guo
Because of its attractive features, direct sequence spread spectrum (DS-SS) technique can be used in telemetering, telecontrol and communications. However, low earth orbit (LEO) satellites channel can experience large Doppler shift which make the acquisition of PN code especially difficult. In this paper, we consider and compare three approaches to the acquisition of direct sequence spread spectrum signal affected by large Doppler frequency shifts. Three sections compose this paper. Section 1 introduces the influence of carrier frequency shifts on the acquisition process of PN code. In section 2, we analyze three measures which can cope with the large Doppler shift of carrier frequency and realize the acquisition of PN code. Computer simulations are performed, which verify the theory analyses. In section 3, contrasts have been done among these three methods mentioned above.
Study on sampling of continuous linear system based on generalized Fourier transform
Huiguang Li
In the research of signal and system, the signal's spectrum and the system's frequency characteristic can be discussed through Fourier Transform (FT) and Laplace Transform (LT). However, some singular signals such as impulse function and signum signal don't satisfy Riemann integration and Lebesgue integration. They are called generalized functions in Maths. This paper will introduce a new definition -- Generalized Fourier Transform (GFT) and will discuss generalized function, Fourier Transform and Laplace Transform under a unified frame. When the continuous linear system is sampled, this paper will propose a new method to judge whether the spectrum will overlap after generalized Fourier transform (GFT). Causal and non-causal systems are studied, and sampling method to maintain system's dynamic performance is presented. The results can be used on ordinary sampling and non-Nyquist sampling. The results also have practical meaning on research of "discretization of continuous linear system" and "non-Nyquist sampling of signal and system." Particularly, condition for ensuring controllability and observability of MIMO continuous systems in references 13 and 14 is just an applicable example of this paper.
Star sensor image acquisition and preprocessing hardware system based on CMOS image sensor and FGPA
Xuetao Hao, Jie Jiang, Guangjun Zhang
Star Sensor is an avionics instrument used to provide the absolute 3-axis attitude of a spacecraft utilizing star observations. It consists of an electronic camera and associated processing electronics. As outcome of advancing state-of-the-art, new generation star sensor features faster, lower cost, power dissipation and size than the first generation star sensor. This paper describes a star sensor anterior image acquisition and pre-processing hardware system based on CMOS image-sensor and FPGA technology. Practically, star images are produced by a simple simulator on PC, acquired by CMOS image sensor, pre-processed by FPGA, saved in SRAM, read out by EPP protocol and validated by an image process software on PC. The hardware part of system acquires images thought CMOS image-sensor controlled by FPGA, then processes image data by a circuit module of FPGA, and save images to SRAM for test. Basic image data for star recognition and attitude determination of spacecrafts are provided by it. As an important reference for developing star sensor prototype, the system validates the performance advantages of new generation star sensor.
Optimized design of embedded DSP system hardware supporting complex algorithms
Yanhua Li, Xiangjun Wang, Xinling Zhou
The paper presents an optimized design method for a flexible and economical embedded DSP system that can implement complex processing algorithms as biometric recognition, real-time image processing, etc. It consists of a floating-point DSP, 512 Kbytes data RAM, 1 Mbytes FLASH program memory, a CPLD for achieving flexible logic control of input channel and a RS-485 transceiver for local network communication. Because of employing a high performance-price ratio DSP TMS320C6712 and a large FLASH in the design, this system permits loading and performing complex algorithms with little algorithm optimization and code reduction. The CPLD provides flexible logic control for the whole DSP board, especially in input channel, and allows convenient interface between different sensors and DSP system. The transceiver circuit can transfer data between DSP and host computer. In the paper, some key technologies are also introduced which make the whole system work efficiently. Because of the characters referred above, the hardware is a perfect flat for multi-channel data collection, image processing, and other signal processing with high performance and adaptability. The application section of this paper presents how this hardware is adapted for the biometric identification system with high identification precision. The result reveals that this hardware is easy to interface with a CMOS imager and is capable of carrying out complex biometric identification algorithms, which require real-time process.
Autonomous celestial orbit determination using Bayesian bootstrap filtering and EKF
Jian-cheng Fang, Xiaolin Ning
The celestial navigation system is one of the important autonomous navigation system for spacecraft. The basic principle of it is using the extended Kalman filter (EKF) and the measurement of angle between celestial bodies estimate the position and velocity of spacecraft. But the EKF may not converge because of the inaccurate initial state. In this paper, a new Bayesian bootstrap filtering approach is used at the initial stage of the filtering interval to provide EKF with an accurate initial state to overcome the divergence problem. Simulation results demonstrated the high precision of orbit determination even in the presence of large initial states errors.
Lithography-independent fabrication of nano-MOS-transistors with W = 25 nm and L = 25 nm
Christian Horst, Klaus T. Kallis, John T. Horstmann, et al.
The 2001 update of the International Technology Roadmap for Semiconductors predicts a printed minimum MOS-transistor channel length of 13 nm for the year 2016, which results in a physical gate length of only 9 nm. The resolution of optical lithography still dramatically increases, but known and proved solutions for structure sizes significantly below 100 nm do not exist up to now. In this paper a new method for the fabrication of extremeley small MOS-transistors with a channel area down to W = 25 nm and L = 25 nm with low demands to the used lithography will be explained. It is based on our deposition and etchback technique which was used in earlier research to produce transistors with very small channel lengths down to 30 nm, while the channel width was not scaled. The used technique is full compatible to the CMOS-Process and therefore easily transferable to almost any other technology line. It results in an excellent homogeneity and reproducibility of the generated structure size.
Intelligent data analysis based on rough correlativity matrix
Zhiqiang Geng, Qunxiong Zhu
This paper proposes a new data analysis method based on rough sets by rough correlativity matrix. In rough set theory, a table called information system or database is used as a special kind of formal language to represent knowledge, a rough correlativity matrix (RCM) can be seen as an internal representation of equivalence relations. Furthermore, this paper provides a new heuristic attributes reduction algorithm based on matrix computing, such as using matrix correlative implements to replace the relations computing between sets. Finally the paper adopts information transition matrix (ITM) of information theory to represent the certainty or uncertainty decision rules based on probability theory, namely, the information matrix composed of certainty factors gives the degree of belief of decision rules, on the contrary the "invert" ITM composed of coverage factor gives the interpretation of decision rules. The result of instance analysis is shown that it is an efficient and feasible method to deal with decision information table.
Effects of clearance on aeroengine performance based on neural network
Wen Chen, Shuming Li, Jie Bai
In recent years, neural network system has got extensive application in the field of aviation because of its strong learning ability, the distributed storage of knowledge, associated synchronization management and restrain of random error etc. There are a lot of network types. Among them, BP (Back Propagation) neural network is the most extensive one that been used. In this paper, BP neural network theory is briefly introduced and is applied to analyze the sample of PW4056 series aero engine. Correlation analysis and theory analysis is adopted to select the input variable. The method of this paper presents a new synthetically prediction. Result indicated that this method could get practical and effective network model. Compared with the traditional regression analysis, neural network have a wilder application foreground.
Full-sky autonomous star identification algorithm based on radial and cyclic features
Xinguo Wei, Guangjun Zhang, Jie Jiang
A full-sky autonomous star identification is presented. Star pattern is generated in the form of radial and cyclic features. Since radial pattern is a reliable feature, it is used for initial match, and cyclic pattern is then used in re-match step. Simulation is done to verify the performance and the result shows this method is more robust against location error compared with grid algorithm under the same condition.
Technology improvement of raising optical tomography resolution
Zhiwei Shi, Yang Li
Optical tomography technology and multiphase flow measurement system involve widely in the industrial and agricultural production, the combination of the two develops very quickly in the research field home and abroad. However, how to improve the longitudinal and transverse resolution of the tomography are always the problem that many researchers have cared about and been devoted to solving all the time. In this paper, we explore ways to solve the problem and some improved methods and techniques are given and use some basic technologies of image reconstruction to enhance the image of optical tomography. The point-spread function δ, which was necessary for the FSD (Fourier self-deconvolution), was obtained in our experimental measurement. Then, we use it to reconstruct and process image so that the image became sharper and cleaner.
Adaptive wavelet domain thresholding denoising
Hongli Shi, Yuanli Cai, Zulian Qiu
In this paper, a new differentiable hard-thresholding function is presented that could replace the hard-thresholding function proposed by Xiao-Ping Zhang as the activation function of wavelet Thresholding Neural Network (TNN). Some numerical experiments show that this hard-thresholding function is more effective in the determination of global optimal solution in signal denoising.
Research on the extraction of quasi-circular object contours using active contour model in polar coordinate
Defan Long, Shangchun Fan
In this paper, we present the active contour model in polar coordinate with a new internal energy term corresponding to the particularity of the quasi-circular object. The energy functional is minimized by the dynamic programming method. A precise initial contour is not necessary in this model which is different from the typical model. The proposed approach is robust to local minima because it searches the whole energy space. Another advantage of this model is that it searches the solution only once, which is different from the iterative method of the traditional model. The approach is tested on synthetic and real images. Results show that the model is robust to local minima and location of the center point.
Measurement Theory and Technique
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Oil-film dynamic coefficient testing system
Hua Zhou, Sanxing Zhao, Hua Xu, et al.
This paper presents an experimental testing system for identification of linear oil-film dynamic coefficients. The testing system consists of a complicated mechanical test rig, a series of electric driven devices and an electronic measurement system. The theory of the testing system, the construction of the system and some measurement techniques are studied in the paper. The mathematic model of the test is derived from a first-order Taylor series expansion of oil-film force formula. Using the data, acquired by the testing system from experiments, the linear oil-film force coefficients can be recognized. The recognized coefficients are valid. The experiments indicate that the testing system is feasible, the design of the test rig is effective and the electric measurement is accurate.
Online expert detection system of microwater in transformer oil
Wenli Zhang, Yutian Wang
This article introduces whole framework of on-line detection of micro-water in transformer oil. It expatiates principium, method and detection process of collection, analysis and identify of signal. Basing on a great deal of examination researches, online expert detection system of micro-water in transformer oil is brought forward. The system is fuzzy neural network (FNN). This principium of FNN mode identifies could realize on-line detection content of micro-water in transformer and avoid foundation of non-line mathematic model. As well as the system could reduce error of measure and its result much more accord with practice data. So the FNN system has a great future in application.
Study on measurement technology of microengines
Lei Guan, Jia-dao Wang, Da-rong Chen
This paper describes the recent progresses of the measurement technology on micro thermal engines with displacement less than 1 cc. An integrative platform characterizing micro engines in terms of their torque, speed, power, temperature field and other properties has been developed and versatile tasks can be accomplishd with satisfactory precision. Applying a DC motor as dynamometers, the power of micro engines can be tested. The temperature field of cylinder wall is measured in this test platform using the IR thermography techniques. Transitional data produced by an incremental coder are captured as function of time by a fast reacting computer and software system. With frequency analysis and digital filter, the dynamic information of micro engines is calculated. Experiments demonstrate that both the temperature and thermal efficiency of micro engines are low as the result of small size. The torque of micro engines changes slightly with the speed at normal operation scope. The transient speed can be used to calculate the gas pressure inside the cylinder and other parameters. Experimental study testified these non-contact methods.
On-line vision measurement system for small thickness
Huijie Zhao, Yonggang Li, Peng Du
A novel vision measurement system specially designed for on-line measurement of thickness of micrograph of work-piece is presented. This system consists of CCD camera, telecentric microscopic lens, illumination, image sampling and processing unit etc. The telecentric microscopic lens and relating LED illumination system is carefully designed to fit the environment on-line such as: illumination, vibration, noise light and out-of focus so as to reduce the measurement error. The following image processing techniques are studied. (1) a new image preprocessing method based on gray level, gradient and spatial information is developed to get rid of the noise in image. (2) several image segmentation methods and the results are analyzed and the evaluation system of image segmentation and the relating evaluation standards are discussed to satisfy the requirement of on-line automatic image segmentation. Finally, an iterative least-square method is utilized to calculate the thickness of the micrograph in order to improve the measurement precision further. The results show that the precision of the vision measurement system is sub-pixel, which can fully satisfy the requirement of industry.
Blade dynamics measurement for microhelicopter using laser
Jungang Lv, Jia-dao Wang, Da-rong Chen
A new experiment method for investigating the flapping motion of micro helicopter blades is described. The method is an untouched approach, two laser beams are used to measure the flapping deflection, one is used as reference beam and another is used as detecting beam. The results show that the method of using laser beam is very simple comparing with the traditional blade-mounted sensors method, and also this untouched approach is reliable for the flapping measurement of the micro helicopter.
Shear transmission mechanical model of circular plate MR clutch
J. Huang, J. W. Huang, Y. Yang, et al.
The operational principle of a circular plate magnetorheological (MR) clutch is introduced. The Bingham model is used to describe the constitutive characteristics of the MR fluids between two circular plates subject to an applied magnetic field. Associated with geometric shape and applied magnetic field onto the clutch, the mathematical model to transmit the torque is established. The expressions of the torque and the output speed are derived to provide the theoretical foundation for the analysis of the clutch. The numerical results indicate that the MR clutch transmits the torque by the shear stress of the fluid. The torque and the output speed can be controlled continuously by changing the strength of the applied magnetic field. With the increase of the gap between two circular plates, the torque decreases.
Design optimization of compound pendulum system for measurement of microthrust
Yongxin Wang, Boxiong Wang, Zhengjiang Liu, et al.
A model of the compound pendulum used for measurement of micro impulses is presented. The effects of pivot friction, air friction and vibration of the stand are simulated through numerical method. To improve the measurement accuracy, it is concluded through the simulation results that the natural period of the compound pendulum should be greater than twenty times the time duration of action of the force being measured. And the moment of inertia of the compound pendulum and the pivot friction should be properly decreased to get a better sensitivity.
Research of measurement assurance program (MAP) for laser interferometer
Yue Feng, Lingfeng Chen, JianRong Ren, et al.
A multi-parameter Measurement Assurance Program (MAP) aim at laser interferometer is discussed detailedly in this paper. Firstly, we summarize the basic implementation process of MAP. After analyzing the measurement parameters of the laser interferometer, we design a set of transfer standard and check standard. Then, the mathematical statistic model of the whole MAP process is presented including the statistic process control and the evaluation of the measurement uncertainty. Lastly, we demonstrate the MAP software we programmed for this process in order to facilitate the implementation. It's clear that our MAP implementation has greatly improved the attending laboratories' confidence for their measurement results.
New nontouching ultrasonic measuring method of fixed liquid level for pressure containers
Zhimin Ma, Min Wang, Ji Cai Hu, et al.
A new non-touching ultrasonic method for measuring the fixed liquid level of containers and its implementing way, based on the penetration attenuation theory of ultrasonic remanent signals container's wall, are first time presented in this paper. For the transducer being only needed to be clung to the outer surface of containers, it is very convenient for the fixing and the sensitivity and reliability also come high. It is especially suitable for measuring and monitoring the upper level of liquid in high-pressure containers and high-corrosive liquid containers.
Verification of measurement uncertainty by computer simulation and experiment
Jianmin Zhu, Zhongyu Wang, Xintao Xia, et al.
For the evaluation errors concerning the typical models for the measurement uncertainty evaluation, the verification method of uncertainties by computer simulation and experiment is proposed in this paper. Computer simulation is adopted to verify the uncertainties obtained through the model in Guide to the Expression of Uncertainty in Measurement, gray evaluation model of the standard uncertainty, and fuzzy evaluation model of the expanded uncertainty. Experimental facility is also designed to verify the measurement uncertainties. Through experiments, the verifications are conducted on the measurement result estimations, expanded uncertainties, coverage probabilities and dispersion range of measurement results obtained through fuzzy evaluation model and the model in Guide to the Expression of Uncertainty in Measurement. As is demonstrated through simulation and experimental results, the measurement uncertainty verification methods proposed in this paper is feasible.
Approach for the evaluation of indirect measurement uncertainty based on neural networks
Jianmin Zhu, Zhongyu Wang, Xintao Xia, et al.
A new approach, in which a nonparametric measurement model is built on the radial basis functional neural networks to evaluate the indirect measurement uncertainty, is proposed in this paper to solve the difficult problem of evaluating the uncertainty of indirect measurement with no measurement model. By determining the center of basis functions based on the clustering result of training samples, neural networks can still be secured a high model building accuracy even when there are relatively fewer training samples. By using the measurement model built to approximately compute the sensitivity coefficient that reflects the uncertainty propagating law of each influence quantity, it is possible to evaluate the result of indirect measurement and its uncertainties. As is demonstrated in simulation results, the method of indirect measurement model building based on neural networks requires no prior knowledge of the measuring process, enjoys a relatively higher modeling accuracy, effectively secures the high accuracy in evaluating the indirect measurement uncertainty and can serve as a beneficial complement to Guide to the Expression of Uncertainty in Measurement.
Multipoint location and error analysis based on the passive detection system
Feng Liu, Dianfa Ping, Xiuqiang Zhang, et al.
In this paper, a method of multipoint location is raised based on the passive detection system and the mathematic model and error model is set up used to measure position. Analyzing a detection system relationship of minimal location fuzziness area and range, relationship of location space error, bearing angle and relationship of circular probable error of multipoint location and range and giving the simulation curve. From the result of the simulation, the location precision of this passive detection system is high. But which should be paid attention to is that the aero error and some other system error are not in the error model, in fact, those errors have a great effect on the location precision of this passive detection system. By corrections, the system error can be reduced, but which can't be removed completely.
Use of wavelet transform on eddy current nondestructive detecting
Xiaoyun Sun, Huiqin Sun, Jianye Liu, et al.
Based on the different characteristics between signal and noise, this paper studied wavelet denoise method on ECNT (Eddy Current Nondestructive Detecting), authors found regularity of noise and nondefect signals arising from the support plate used to hold the tubes, and introduced a new method removing the support plate disturbance using wavelet multi-scaling edge detecting technology. The result shows that this method is better than the current one in the respect of hardware cost.
Estimation of several types of correlation information between sound and electromagnetic waves leaked from VDT environment based on the introduction of fuzzy probability and the prediction of probability distribution
Akira Ikuta, Mitsuo Ohta, Seijiro Hiromitsu
In this paper, a signal processing method considering not only linear correlation but also the higher order nonlinear correlation information is proposed on the basis of fuzzy observation data, in order to find the mutual relationship between sound and electromagnetic waves leaked from an electronic information equipment. More specifically, by applying the well-known fuzzy probability to an expression on the multi-dimensional probability distribution in an orthogonal expansion series form reflecting systematically various types of correlation information, a method to estimate precisely the correlation information between the variables from the conditional moment statistics of fuzzy variables is proposed. The effectiveness of the proposed theory is experimentally confirmed by applying it to the observation data leaked from VDT in the actual work environment.
Evaluation method for complex sound environment system under unknown structure and existence of observation noise
Hisako Masuike, Akira Ikuta, Mitsuo Ohta
The actual sound environment system exhibits various types of linear and non-linear characteristics, and it often contains an unknown structure. Furthermore, the processes observed in the sound environment inevitably contain observation noise or uncertain factors. In this paper, a method for estimating the specific signal for a sound environment system with unknown structure and observation noise of unknown statistical property is proposed by introducing a system model of the conditional probability type. The effectiveness of the proposed theoretical method is confirmed by applying it to the actual problem of signal estimation of the sound environment.
High accuracy position method based on computer vision and error analysis
Shihao Chen, Zhongke Shi
The study of high accuracy position system is becoming the hotspot in the field of autocontrol. And positioning is one of the most researched tasks in vision system. So we decide to solve the object locating by using the image processing method. This paper describes a new method of high accuracy positioning method through vision system. In the proposed method, an edge-detection filter is designed for a certain running condition. Here, the filter contains two mainly parts: one is image-processing module, this module is to implement edge detection, it contains of multi-level threshold self-adapting segmentation, edge-detection and edge filter; the other one is object-locating module, it is to point out the location of each object in high accurate, and it is made up of medium-filtering and curve-fitting. This paper gives some analysis error for the method to prove the feasibility of vision in position detecting. Finally, to verify the availability of the method, an example of positioning worktable, which is using the proposed method, is given at the end of the paper. Results show that the method can accurately detect the position of measured object and identify object attitude.
Digital processing of complex modulated ultrasonic signals in flow measurement
Hans Volker
Many practical applications require special solutions for the digital demodulation of complex modulated signals. A typical example is the ultrasonic signal which is complex modulated by turbulent structures or vortices in the flow. The information about the modulation is in the sidebands of the signal which can be separated by undersampling. The most interesting phase angle can be detected by a 90 degree shifted sampling. This sampling can be extended to a shift of (n • 360 + 90) degrees. The zero point adjustment of the phase angle can be determined by the analysis of the density distribution function of the phase angle. In the case of very high modulation degrees extended Kalman filters have been proved good.
Uncertainty analysis and precision assurance based on large diameter measurement by multiroller method
Xiaohuai Chen, Zhenying Cheng
In this paper, main error sources and error transitive relationship in large diameter measurement by multi-roller method are analyzed completely. On the basis of uncertainty estimation, the temperature effect on the measurement precision of large diameter is emphatically discussed here. Temperature error correction and residual error after correction are studied and methods are presented to improve the effect of temperature error correction. Proper error allocation is introduced to guarantee that large diameter measurement precision can be significantly increased.
A new effective method for removing measurement noise
Donghui Liu, Xiaoyun Sun, Nan Gao, et al.
Based on the characteristics at different scales between signal and measure noise, this paper studied wavelet denoise method on ECNT (Eddy Current Nondestructive Detection). After analyzing the two current denoise methods using wavelet transform, such as Mallat multi-scaling edge detecting or thresholds method, authors introduced a new method. The result shows that this method is better than two others.
Design of anti-aliasing filter for dynamic signal measurement
Jinyong Yao, Chuanri Li
Anti-aliasing filter is used to remove the frequency components higher than Nyquist frequency so as to reduce alias error. It is very important for precise measurement and analysis of dynamic signal. The maximum useable frequency range of the dynamic signal measurement system is derived in this paper. The method for design and optimization of a switched capacitor filter based tunable anti-aliasing filter is discussed in detail. The test result shows that the filter can satisfy the strict system requirement through careful design and implementation, while the filter circuit is relative simple.
The study of fast identifying methods on ECNT
Xiaoyun Sun, Donghui Liu, Nan Gao, et al.
BP network is applied on ECNT (Eddy Current Nondestructive Testing) to identify defect fast in this paper. Due to BP network having the disadvantages of large numbers of iteration and local minimum values, authors use RBF network on ECNT. The results show that numbers of iteration using RBF network are reduced faster than using BP network, and it is possible to detect online by RBF network.
Shape measurement of BGA for analysis of defects by x-ray imaging
Tetsuhiro Sumimoto, T. Maruyama, Yoshiharu Azuma, et al.
This paper deals with the development of image analysis for the detection of defects at BGA solder joints in PC boards by using X-ray imaging. We can't detect visually defects at BGA solder joints, because they are hidden under the IC package. To improve a cost performance and the reliability of PC boards, an inspection of BGA is required in the surface mount process. Types of defects at BGA solder joints are solder bridge, missing connection, solder voids, open connection and miss-registration of parts. As we can find mostly solder bridge in these defects, we pick up this to detect solder bridge in a production line. The problems of image analysis for the detection of defects at BGA solder joints are the detection accuracy and image processing time according to a line speed of production. To get design data for the development of the inspection system, which can be used easily in the surface mount process, it is important to develop image analysis techniques based on X-ray image data. At the first step of our study, we attempt to measure the shape of BGA based on X-ray imaging.
Study on microdisplacement measurement by laser interference and image processing methods
Lei Zheng, Jia-dao Wang, Xianmei Kong, et al.
This paper presents a measurement system that can measure micro displacement by laser interference and image process methods. The displacement is measured by testing the relative moving distance between the movable mirror and the fixed mirror. Based on Michelson interference theory, the interference stripe images produced by a monochromatic laser source is collected by the CCD, which is used in the system to track the motion of PZT. The curve of light distribution is analyzed and dealt by Fourier Transformation and Low-pass Filtering methods. Least Squares Fit method is used to get normal amplitude, angle frequency and phase of the curve of light distribution and account the change of phases. Applying this measuring system, the micro-displacement is measured and obtains good test results.
Method for the enhancement of moving image sequence acquired by MAVs
A novel frame shift and integral method for the enhancement of moving image sequence acquired by MAVs is introduced. In this paper, we first describe the method of frame shift and integral, then the relationship between the shift value and flight velocity, flight height of MAVs is discussed, and the model to calculate the shift value of moving images is established. Moreover, the solution to remove the ladder stripe caused the opening section of shifted image is given. Finally, the imaging in the flight of MAVs is simulated. The experimental results show that 1) The calculated values of the shift value accord with the actual values, 2) With the increasing of the number of integrated frames, the SNR (signal noise ratio) of moving image is increased obviously.
Optimal measurement planning using fuzzy-set theory
Xintao Xia, Zhongyu Wang, Yongsheng Gao
In precision measurement, it is known that a measurement process involves errors or factors of different kinds and types. Using the prior knowledge on the relationship between the measured variables and the factors, the best measurement plan may be obtainable if a target function on the errors is minimized. In many cases, however, the relationship may not be clear since non-quantitative factors are involved, making the finding of the best plan using methods such as the statistics method quite difficult. A new method based the fuzzy-set theory is proposed to solve this problem. In this method, the membership grade is maximized. The concept of quasi-perfect plan is presented. Mathematical modes are established and case studies are presented in order to demonstrate the feasibility of the proposed method.
Piezoresistive pressure sensors in CVD diamond for high-temperature applications
Ralf Otterbach, Ulrich Hilleringmann
The fabrication of piezo-resistive pressure sensors for high temperature applications by the selective removal of CVD-diamond is limited due to the jutting physical properties of this material, which result in insufficient etching rates. A novel technique with distinctly increased etching rates due to a modified sample arrangement inside of a commercially available reactive ion etching (RIE) reactor overcomes this limitation by a restricted plasma volume. Rates up to 334 nm/min imply an increase of more than one order of magnitude in comparison with additional measurements utilizing a standard etching technique. Furthermore, the electrical response of a fabricated sensor on pressure is demonstrated.
Photoelectronic Technology and Instruments
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Research on the application of vision-based autonomous navigation to the landing of the UAV
Xinhua Liu, Yunfeng Cao
In this paper, we present a vision algorithm to measure the orientation of the UAV with respect to the runway during the landing. The horizon line is detected first and with the information of the horizon line, the boundary angles of the runway are recovered. From the horizon and the boundary angles, the pitch and bank angles can be determined. The range in which the yaw angle locates is also obtained.
Mobile robot localization based on fixation vision geometric constraint
Xiao Li, Hongyue Zhang
This paper presents a feasible algorithm for mobile robot localization. Localization system is composed of an encoder, an electronical compass, a fixation vision system including a CCD camera and a stepping motor. Multisensor information fusion technology, extended information filter, is adopted for estimating the position and heading of robot. New measurement equation which is based on fixation vision geometric constraint is proposed in this paper. The coordinates of the landmark is not needed to know in this method, in other words, any point in the observed scene can be selected as a landmark. The results of simulation show the algorithm validity. The comparative results show this algorithm has advantage in autonomous mobile robot localization application than Dead-Reckoning.
Stereo image matching based on phase unwrapping
Huijie Zhao, Jianjie Li
This paper introduced one method of image matching based on the phase unwrapped. In the binocular measure, for restructuring the objects' 3D surfaces, the coordinates of points on the object surface must be known. In the conventional method of 3D measurement using two sensors, the interest points in different images, which were homologous must be located in order to ensure their corresponding relationship. However, image matching based on phase undone and unwrapped could find out any points whch have the corresponding relationship in two images, even though they were not the interest points in conventional meaning.
Analysis of tracking performance for altitude-azimuth pedestal near the zenith
Tongbo Ji, Xiuhua Yang, Juan Chen, et al.
The secant compensation must be applied in the servo system of the azimuth axis for the altitude-azimuth pedestal. The secant compensation value changes acutely while the elevation goes high. The pedestal can't follow the target smoothly so as to lose the target near the zenith. The zenith exclusion region, as is the main shortage of the altitude-azimuth pedestal, was analyzed. The conclusion is that the scope of the zenith exclusion region was restricted by three parameters; maximum azimuth angular velocity of tracking mount, flight level and airspeed of the target. And then, the factors that influence high-elevation tracking performance are analyzed. The dynamic delay is usually regarded as the main influencing factor. The effect of equivalent insensitive-zone and random tracking error are often neglected. Nevertheless, it is clearly important to be aware of them in some case. The factors discussed above were tested with the experiment. The actual track data draw a conclusion that the last two factors become the main influencing factors in the case of tracking slow-moving targets. It verified that the theoretical analysis is correct and is very valuable for engineering.
Three-dimensional volume rendering from sector scanning images
Jin Li, Dianguo Xu, Wang Cong
Several problems related to the three-dimensional volume rendering from sector scanning images have been deeply studied in this paper. To counter the key problem that the points on the two adjacent images are not same interval, the recursive interpolation algorithm for the unequal interval, by which the data changes continuously and gradually, has been put forward in this paper. Therefore, the problem, how to make interpolation amid the unequal interval in the volume rendering from sector scanning images, has been well solved. Besides, the formation of outer curved layer volume is another key problem in the volume rendering from sector scanning images. The algorithm based on cubic parameter spline function for forming the outer curved layer volume has been proposed in this paper as well. Using this algorithm, the smooth outer surface can be obtained. On the basis of unparalleled two-dimensional section images, the three-dimension reconstruction from sector scanning has been firstly realized using volume rendering. And, several tested images of irregular model from sector scanning are presented. The tested results indicate that the algorithms presented in this paper are correct and practicable. The effect of reconstructed images is satisfactory.
Image reconstruction of 2D concentration distribution of particle flow with extinction optical tomography
Yang Li, Renhuang Wang, Yingna Zheng
Optical tomography, as a novel technique developed recently, has drawn more and more interest among imaging of biology tissue, astronomy and industrial process monitoring, and so on. Extinction method is one of traditional measurement for particle concentration, which can be improve a novel optical measurement with computed tomography (CT) to reconstruct image of particle concentration distribution. In this paper, the theoretical model of exctinction optical tomography was presented, the relationship between geometric structure of optical array sensors and section drawings of measured area was analyzed, and so did between the structure and spatial resolution. In experiments, 8 x 8 orthogonal array of optical sensors with two-directions projection are used for flow imaging by means of FBP, which is for capturing movement track of a glass canaliculus with arenaceous quartz inside in a section. Furthermore, image reconstructions based on optical array sensors with two-directional angles and four-directional angles are simulated numerically and some significant results can be found from the simulated results.
Analysis of sensing field to array sensor used for optical tomography
Yang Li, Renhuang Wang, Yingna Zheng, et al.
Array optical tomographic sensor is the key parts of optical tomography system. The analysis of sensing field to optical tomographic sensor is not only helpful to learn the interactional relation between the stimulating light field and the measured object's characteristics, but also instructive to optimize the spatial structure of array sensor and further illustrate the optical CT layer diagram rationally. The sensitivity distribution in sensing field of optical tomographic sensor mainly relates with the light wavelength, the extinction capability of measured media and the spatial structure of array sensors. By dividing the measured area in the form of square grid unit, analyzing the two-dimension spatial distribution relation of multi-azimuth fan beam in measured area and unitizing the sensitivity coefficient, the approximate calculating method of sensitivity distribution of optical sensing field is educes this paper. Based on the above-mentioned sensitivity distribution map, the spatial resolution and optimization parameters of sensors' array structure are further analyzed.
Measurement of locomotory particles by fast shooting with CCD
Li Ge, Yang Li, Yingna Zheng, et al.
This paper presents a non-contact method to measure the so-called moving big particles by using conventional optical measurement together with image processing technique. With a slow-motion CCD camera, real-time images of the particles are taken displaying little bright points distributed on a dark background. Next, the particles in the image are separated from background via binary manipulating so that the whole image contains background pixels whose values are zero and particles pixels whose values are one. Furthermore, mathematical morphology is used to amend the anemographic images caused by CCD scan mode. Finally statistics of the size and number of particles are obtained directly through amended binary images.
Study on thermal control of x-ray mask during post-exposure bake
Yongkun Wang, Jianzu Yu, Lei Yu, et al.
The temperature distribution on the surface of the mask, during post exposure bake (PEB) of the X-ray mask after electron beam writing (EBW), is very important for controlling the mask critical dimension(CD). In this paper, three-dimensional finite element (FE) thermal model of the X-ray mask has been set up. The results of the numerical simulation indicate that it will take 2.16 seconds for PEB to get thermal steady when the boundary conditions of the top surface of the resist are natural convections, and that the temperature distribution of the mask is non-uniform, and the maximum temperature difference is 10.19°C, which will most likely make the resist at the high temperature region baked excessively. By using insulation measures, the boundary conditions of the top surface of the resist are changed to adiabatic conditions, and the temperature distribution of the mask is very uniform, which will reduce the influence on the absorber CD from PEB.
Vector-based synthesis of finite aperiodic diffractive micro-optical elements with subwavelength structures as beam deflectors
Di Feng, Yingbai Yan, Qiaofeng Tan
An iterative optimization-based synthesis algorithm has been presented for the design of diffractive micro-optical elements (DMOE's) with subwavelength structures as beam controllers. The DMOE's with subwavelength structures only require single step fabrication, but the subwavelength and aperiodic nature of the DMOE's prevent the use of scalar diffraction theory and the use of coupled-wave theory. We apply the finite-difference time-domain (FDTD) method as the vector model and the iterative plane wave spectrum algorithm (IPWS) as the synthesis algorithm, which can make the design of DMOE's in reasonable time frames. The IPWS, the FDTD method, the plane wave spectrum propagation method have been discussed and a beam deflector with subwavelength structures has been designed.
Design for the miniaturized rotary table of the high-precision and high-speed phototheodolite
Feng Zhang, Weiqiang Liu, Xiancun Song, et al.
The high precision and high speed miniaturized phototheodolite system composed of two phototheodolites and other apparatus can measure the azimuth angle and the pitching angle of the aircrafts when they are taking off in aerodromes and ranges. And the measure system can also take down the continuous flight attitude of the aircrafts. The rotary table of the phototheodolite is one of the most important components of the measure system. It sustains the theodolite and affects the system's precision. This paper elaborates on the issues, such as the comparison of different designs, the reasons of confirming the best design, the analysis of the precision of the rotary table. The design for the miniaturized rotary table lays a firm foundation for the design of the smaller and more economical high precision and high speed phototheodolite measure system.
Nonscanning 3D profile parallel confocal detecting system based on DLP technology
Yonghong Wang, Xiaofen Yu, Ruijun Li, et al.
Based on micro-optical devices, a non-scanning 3D profile detecting system is proposed. A 2D point light source array produced by the Micro-optical device is used to form parallel confocal system. It realizes whole-field in-step detecting of measuring plane. In the detecting system, Digital Light Processing (DLP) technology is used, and a Digital Micromirror Device (DMD) substitutes conventional micro-optical elements (like micro-lens array). Therefore, it realizes portable and programmable 2D point light source imaging. All the measuring parameters that influence the measurement can easily be adapted by software to satisfy different requests of measurement. The construction and working principle of the no-scanning 3D detecting system is studied. The method of 3D profile reconstruction is introduced. Experiment result is obtained, which indicates that DLP technology is applicable in confocal detecting.
Laser interferometry gray decision-making model
Ming Fang, Zhongyu Wang, Min Lin
The selection of the principle is an important problem during the preliminary phase of the laser interferometry instrument's designing. For lacks of an effective method, the conventional decision-making is hard to avoid the influence of the designer's subjective sensation. To solve the problem, this paper proposes a new method based on the gray system theory. Using this novel decision-making method, a selection is made between four common interferometries under a certain condition. Theoretical analysis and experiments prove that the method is effective, accurate and easy to be carried out.
Research development of the gray error theory and applications in dynamic measurement
Zhongyu Wang, Xintao Xia, Jianmin Zhu, et al.
A general review of the recent research development in the field of gray measurement error theory is presented in this paper. The concept, principle, algorithm and its applications of the novel method using gray system theory to characterize the measurement errors in dynamic process is shown.
Novel high-precision optical thin film monitor
Cheng Zhang, Weiqiang Lu, Yongtian Wang
High-precision optical thin-film deposition monitor is a key technology for modern optical thin-film fabrication. A new monitor is developed based on double beam one lock-in amplifier. It allows the precise cut off of layers through the deposition. Experimental results show that the monitor can be used in a high-precision, fully automatic control optical thin-film deposition system.
Key technologies of a utility management simulation system
Qiaozhen Liu, Juan Chen, Lihua Qiu, et al.
The simulation platform of utility management system is a distributed computer network hierarchy which is demanded to complete certain real-time tasks during scheduled time. In addition, to make the airplane with high reliability, the real-time tasks need to be completed smoothly when the system is in the fault situation. Taking the real-time character and fault-tolerance of the system into account, this paper proposes the topological architecture of the simulation platform and its simplified model, and concludes the cost function term which makes the redundant system with minimum cost on the condition of load balance.
Research on image autofocus system based on neural network
Guojin Chen, Bin Liu, Ye Gong, et al.
AF (auto-focus) becomes a very important function in many kinds of photoelectricity imaging systems. The popular AF is realized by means of measuring distance. In this paper, a new AF means is presented, which is realized by a neural network. Because the NN (neural network) has the capacity of non-linear processing, it can be used to estimate image's definition and adjust PID controller's parameters. When such a NN is embedded in an AF system, the system will have the features of real time, high veracity and self-adaptation.
Research on image definition function use in a real-time autofocusing system
Guojin Chen, Kesong Zhang, Ye Gong, et al.
Real time auto-focus systems based on image analyzing are different from other auto-focus systems based on range measuring in high precision of focusing and low accuracy demand of assembling and manufacturing the parts. To construct a real time auto-focus system based on image pattern recognition, the key is foundation of image definition and preprocessing methods for original image. The paper puts forward an image definition function arithmetic combining the power spectrum based on FFT with the wavelet filter based on Meyer's wavelet. Fast FFT can be realized with specialized hardware. It can improve the computing speed of image definition function and provide the auto-focus system based on image analyzing with a fine real time and high accurate model.
Research on distributed curvature modal sensors with optical fiber on vibration measurement for thin structures
Ling Zhou, Yang Li, Zhong Situ, et al.
Thin structures have been applied widely in different areas of engineering. They are prone to elastic vibration when submit to external dynamic excitations or interference, which will not only lower system stability, but also threaten the people's lives. Thus, it is significant to research this topic in depth. Generally, many acceleration sensors are put on the cover of the structure to measure the vibrations. Also, strain sensors have been recently used for measuring vibration. However, strain is difficult to measure in thin structures and there are also limitations when applying multi-spot distributed measurement method. Based on the theory that the vibration of practical structure can be decoupled into multiple vibration modes, a new concept of curvature modal sensors with optical fiber is proposed to measure vibration modes.
Adaptive DPSD algorithm with automatic tracking of reference signal frequency
Many applications concerning the estimation of the parameters of the sinusoidal signal under the condition of ultra-low SNR (-30 to -60 dB) are realized with Phase Sensitive Detection (PSD). It is necessary for a traditional analogue PSD to have a reference signal that has the same frequency as the measured sinusoidal signal, but in many cases such a reference signal is difficult to obtain. An adaptive DPSD (digital phase sensitive detector) algorithm with the automatic tracking of the reference signal frequency is presented in this paper. The frequency response and the realization of the DPSD algorithm are studied. Simulation results coincide with the theoretical analysis. The proposed algorithm can be used to estimate the parameters of a sinusoidal signal under the condition of ultra-low SNR (-30 to -60 dB).
Design of novel part-compensating lens used in aspheric testing
A novel aspheric surface testing method using part-compensating lens is presented in this paper. Researches are made to the specific design requirement and design method of part-compensating lens. The design requirement is applied in the optimization design of the part-compensating lens to three kinds of aspheric surfaces, and it is proved that the structure of part-compensating lens is much simpler than that of null compensator. Analysis is made about the asphericity compensation range of each part-compensating lens, some range can be 30 λ. The results demonstrate that aspheric surfaces with different relative aperture and asphericity can be compensated by part-compensating lens that is simple and easily fabricated, and the shape error of aspheric surfaces can be measured.
Saturation problems of a two-color thermometer
Riwu Bai, Pu Wang
Saturation radiance in light-spectrum and sensor amplifying circuit saturation have influence on the accuracy and truth of 2-colors thermometer, which will result in non-single-value and be wrong in display.
Method for improving the low-speed performance of an optoelectronic tracking system
Xiaoquan Han, Tao Chen, Juan Chen
The tracking servo system of an optoelectronic tracking system that is driven by unipolar PWM power amplifier has the features of high efficiency, wide speed regulation range. But the phenomena such as instability at low-speed and positioning exist in the system because of dead-zone nonlinearity, which result in steady error and low tracking precision. A method for improving low-speed performance of an optoelectronic Tracking System is given in the paper: using bipolar PWM power amplifier to replace unipolar PWM power amplifier and we did some comparative experiments. The experimental results showed that using bipolar PWM power amplifier to replace unipolar PWM power amplifier is an effective method for improving the low-speed performance of the optoelectronic tracking system.
An embedded route finder and tracing system for a stepped robot
Xiangjun Wang, Zhi Li, Xinling Zhou
The paper presents a new embedded sensor method of non-contact automatic route-finding and route-tracing for stepped robot. The final system is designed and integrated into a single hardware PCB with size of 30x30x15 mm3. A line scanning charge couple device (CCD) with 1024 pixels is used to obtain the plane scene of route, and a pair of infrared LED is employed to provide the illumination of the route-finder. Moreover, this route-finder still includes a micro lens, CCD driver, instrumentation pre-amplifier, edge extracting circuit, FPGA circuit for position measure and logic control, direction and state display of the route-finder by LED, moving direction control pins output and power manage circuits. The router-finder for stepped robot has the advantages of simple and fast operation, easy assembly with robot, small volume, high sensitivity and precision for route-finding and tracing. The paper outlines in detail the principle of the route-finding and tracing by edge extraction and edge position measure using a CCD image sensor with a micro lens assisted by infrared illumination and a FPGA circuit. Some relational edge extraction and measure algorithms suitable for embedded system with FPGA are introduced in the paper too. Finally, the actual experiment results are given.
Pickup of ion beam etching depth information during microfabrication
Guangxing Zhao, Yan Wang
Based on scalar quantity diffraction theory, the phase grating of micro-optics structure is studied. The light intensity distribution of diffraction fields is obtained. Results show that the peak position of light intensity moved with the variation of ion beam etching depth. The conclusion can be used in the pick-up of etching depth information during micro-fabrication, and it has important significance in ion beam etching depth's accurate control.
Automatic Measurement, Control, Bus, and Network
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Radio-based control of a linear motor for the NBP railway system
Andreas Pottharst, Horst Grotstollen
In the course of the NBP (Neue Bahntechnik Paderborn) project a testing plant is used for investigations on autonomous railway vehicles (shuttles) driven by linear motors. At the testing plant the linear motors are of the doubly-fed long-stator type which is used to transfer energy to the shuttles. In accordance with the two parts of the linear motor being distributed to the vehicles and the track the drive control hardware consists of different units which are distributed to stationary plants and moving shuttles. Communication between these control units cannot be performed but by radio transmission which is a demanding task because strong realtime requirments of drive control must be fulfilled.
Three-dimensional shape measurement system using optical spatial modulator and zoom camera
Katsumi Tsujioka, Jing-Nan Liu, Yoshihisa Uchida, et al.
An automatic measurement system of three-dimensional shapes by a projection method with striped patterns from an optical spatial modulator has been developed. Patterns on the surface of the object were taken into a computer by a CCD camera, and the 3D cocordinate of the surface of the object was calculated according to a principle of a trigonometry measurement. This system has the following advantages. (1) It is possible to capture the surface topography without any contact. (2) The time required for the measurements is shorter than the light-section method. (3) The optical spatial modulator using a liquid crystal projector is possible to control the striped patterns accurately by the computer. (4) It is possible to measure precisely and to expand the measurement area using a zoom camera. In this study, we developed the method with using zooming of a CCD camera image. By using zooming of a CCD camera image, the measurement accuracy improved and the measurement range was expandable.
Classification of mammographic breast density by the histogram approach using neural networks
Sachiko Goto, Yoshiharu Azuma, Tetsuhiro Sumimoto, et al.
Our aim was to improve the accuracy of classifying x-ray mammographic breast densities. The histogram approach using the neural network was used for the purpose of constructing a flexible system. In this study the phantom of the synthetic breast-equivalent resin material for the process of the A/D conversion of mammograms was employed. The digital values can offset the difference in characteristics between the mammography system, the unit, etc. Furthermore the features of our system use the neural network, and then tune the neural network by the histogram of the digital values and by the radiologists' and expert mammographers' assessment ability. Although there was an observer's bias, our system was able to classify the breast density automatically according to that observer. This is only possible if the observer has been trained to some extent and is capable of maintaining an objective assessment according to the assessment criteria.
Virtual test system of cable tension force based on LabVIEW
Qi Fu, Yan Deng, Taopeng Qiao, et al.
Measuring the tension force of cable is important to cable-stayed bridges, but there is lack of effective test systems. To solve this problem, a new test system of cable force based on LabVIEW was developed according to vibration frequency method. This paper discussed the functions and characteristics of this system beginning from its theoretical background. Through given hardware components, the vibration signal of cable was collected and transferred to computer. Then the signal was processed and the cable force could be reckoned by special designed software program. During spectrum analysis, the most important step in signal processing, DTFT method was used to obtain precise fundamental frequency. In this system, LabVIEW environment was adopted to ensure high reliability. Field experiment has proved that the virtual test system can fulfill the requirement of cable force measurement very well.
Real-time research on local monitoring station of distributed control system
Ming Li, Tianshu Huang, Tao Sun
The local monitoring station is located in the bottom of Distributed Control System (DCS), which is connected to the producing objects directly and has high demand for real-time. The real-time of the local monitoring station can be improved from the point of communication subnet. Simplifying protocol is an important way to improve the real-time of communication subnet. The local process data of DCS is very short, and each basic controller in local layer is a relatively independent system, so the information that needs to be exchanged between controllers is not large. According to this characteristic, a kind of local monitoring station is designed in this paper, in which the communication mode is a master-slave mode and the protocol used is simplified. This type of communication subnet can perfectly improve the real-time of the local monitoring station.
Measuring of network vulnerability
Xianpei Wang, Jun Zhang, Quande Wang
The application of computer network has mushroomed with the networking manufacture, networking instruments and etc. The ability of the production or system that can endures the breakage and the fault is a very important performance index. Especially today, the problems by reason of information security including hidden failures and defects in the system directly threaten the security and performance of system. This performance index to indicate these cases is the vulnerability. Networks vulnerability is defined as the abilities of network which to endure attacks, destroy and faults, also being called invulnerability of network. Vulnerability is often measured by the degree of vulnerability, which directly indicates the magnitude of invulnerability. This paper firstly introduces the conception of networks vulnerability, and distinct the analysis methods of networks vulnerability. The results of this paper are being looked forward to giving much direction on the system analysis and synthesis too.
Topologies for low-voltage regulator modules
Hermann Wetzel, Norbert Frohleke, Horst Grotstollen
Three different topologies for low voltage regulator modules are compared in this paper. A Push-Pull converter (PPC) equipped with a novel hybrid gating scheme, which supports synchronous and external driving is proposed and compared to a Two-Transistor Forward Converter (2TFC) with a simple enhanced gating circuit of the MOSFET based rectification. Finally, an asymmetrical driven Half Bridge converter (AHBC) with integrated magnetic components and synchronous rectifier (SR) supplements the comparison. This topology was discussed only recently with respect to the low voltage topic. Prototypes for three topologies were developed, operated at 48 V input voltage and deliver 1.7 V at 18 A output current.
Multisensor integrated automated inspection system
Huacheng Chen, Boxiong Wang, Xiuzhi Luo, et al.
It is a trend of modern measurement technology to combine the contact and non-contact measurement techniques together to realize a more efficient and high-precision inspection of manufactured products. Based on an analysis of existing optical inspection technologies and the merits and shortcomings of coordinate measuring machine (CMM) technique, we propose a multi-sensor automatic inspection system, which combines the coordinate measuring machine with non-contact optical measuring apparatus and can select automatically either of the two methods for different (simple-geometry or complex free-form) measured objects so as to raise the accuracy amd efficiency of measurement. The general planning and key components of the system are discussed.
A kind of SF6 density regulator based on the control of microprocessor
Xianpei Wang, Anyu Cheng, Juan Li, et al.
This paper presents a precise and credible pressure calibration instrument. To improve the precision of the SF6 density measured, the gas density in the cabin is sampling, and then the density is calibrated and current density in the cabin and the real density value to be calibrated are displayed.
Implementation of weak signal detection by Duffing oscillator in virtual instruments
Shilin Li, Qiufeng Shang, Chengqun Yin, et al.
Chaotic systems are sensitive to certain signals and immune to noise at the same time, the properties of which make it potential application in signal detection and equipment fault diagnosis. In this paper, some Virtual Instruments (VIs) are designed to implement the Duffing oscillator which is used for weak signal detection. The basic design idea of the VIs is presented and the diagrams of some VIs are shown in the paper. At last, some detection results of the simulated signals and the real signals are given. It is shown that to use VI for the detection in the field is advantageous.
Design of automatic test system software
Liang Xu, Xingshan Li
Along with the widely use of Automatic Test System (ATS) in many fields, more and more attention are paid on the compatibility and exchangeability in the design of automatic test software. This makes the developer concentrate themselves more on the development of Test Program Set (TPS) and then the cost and time of development are reduced by the decrease of repeated works. This paper describes the Automatic Test System software design for testing on-board equipments of helicopters. A0ccording to the layer standards of ABBET and application of database, we realize the layer design of the system module through the application of database technique by which the general ability and exchangeability are increased.
Applying the idea of SAFER to develop a new automatic test system
Wen Li, Kai Xiao, Xianzhou Gui
SAFER is a new computer architecture. Analytically redundant and dynamic upgradeability are two key concepts of SAFER. Applying the idea of SAFER to develop a new automatic test system can improve the reliability of the new system and the acceptability by users.
Automatic aircraft object detection in aerial images
Yingchun Li, Hexin Chen, Yunhuan Mei, et al.
Image segmentation that partitions a given image into meaningful regions is an important task of image analysis for recognition. This paper describes the segmentation of objects in complex aerial images that contain aircraft objects in the airport. The proposed approach is automatically to detect aircraft objects in the aerial images based on the adaptive clustering segmentation algorithm. Following an edge-linking procedure, the regions of objects can be bounded by closed boundaries. The amount of objects can be determined before and after the image denoise. Experiments on a variety of aerial images have shown correct segmentation, regardless of the complexity of background in images.
Design and realization of a remote monitor system for equipment based on DCOM technology
Zhong Situ, Dazhi Wang, Xuelian Jiang, et al.
The component writing with COM (Component Object Module) technology has a strong reusable ability and can run on different operating system; DCOM (Distributed Component Object Module) technology is an industry standard. With DCOM, our COM object can communicate with each other through network and conceals the realization details in the low-layer communication; with DirectX, smooth 3D emulation can be achieved under a general hardware conditions. Through analyzing the existing remote monitor technology, the paper realizes a kind of remote monitor system to equipment based on DCOM and DirectX technology. Experimental results show that the system is an advanced and effective system with excellent distributed monitor ability and high visibility.
Virtual oscilloscope based on VXIbus
Lei Yang, Le-Ping Yang
This paper introduces how to design the software of virtual oscilloscope based on VXI devices. This oscilloscope has multi functions, multi channels and high resolution. The test data can be stored and shared through network. And the oscilloscope supports remote control. The emphasis is put on the virtual instrument software structure analysis, the database application in virtual instrument software and on how to use plug ins to enhance the efficiency and reliability of virtual instruments.
Driving methods of universal DAQ cards in LabVIEW
Haitao Li, Lei Yang, Le-Ping Yang
The paper discusses four methods of driving the universal DAQ cards in LabVIEW, and summarizes their advantages and disadvantages. The four methods resolve the problem of driving universal DAQ cards in LabVIEW.
Remote data acquisition system based on DataSocket technology
Haitao Li, Le-Ping Yang
The paper discusses a design of a remote data acquisition system based on DataSocket technology, the main idea of this system is that using the abilities of high speed live data publishing and data sharing of DataSocket technology to transmit the control commands of DAQ cards and measurement data. This system resolves the problems of using RDA technology to realize remote data acquisition.
Mission planning algorithm for autonomous control system of unmanned air vehicle
Zhouyi Yu, Rui Zhou, Zongji Chen
Unmanned Air Vehicles (UAVs) are becoming an integral part of future military forces. This paper presents a three-layer autonomous control architecture for UAV and discusses how each layer functions to enable autonomous operation of UAV. Mission planning is the kernel of UAV autonomous control system. In this paper, PGG (Plan-Goal Graph)-based mission planning algorithm is discussed in detail and used to solve the UAV Suppress Enemy Air Defense (SEAD) mission planning problem successfully.
Real-time query system based on three layers
Deshi Li, Jincheng Wang
This paper has introduced the development of Database application promoted by Internet and the characteristic of Java, systematically analyzed how to realize the three layers application based on B/S mode and the predominance of Java in implementing it. Based on this analyzing we select Java as platform, exploit the real time query system based on three layers: the synthetically query system for electric power department of ZhuZhou City, HuNan Province.
Device USB interface and software development for electric parameter measuring instrument
Deshi Li, Jian Chen, Yadong Wu
Aimed at general devices development, this paper discussed the development of USB interface and software development. With an example, using PDIUSBD12 which support parallel interface, the paper analyzed its technical characteristics. Designed different interface circuit with 80C52 singlechip microcomputer and TMS320C54 series digital signal processor, analyzed the address allocation, register access. According to USB1.1 standard protocol, designed the device software and application layer protocol. The paper designed the data exchange protocol, and carried out system functions.
Distributed control and measurement system (DCS) preferable to design-for-testability (DfT) for analog ICs
Guonan Zhao, Jianping Hu, Fuhong Zhang, et al.
A fast and efficient method for element-identification and Analog-DfT with the aid of ac Josephson voltages has been found from several papers listed in our references where specified terms Novel-Optimum-Identification (NOI) and Fast-Convergence-Identification (FCI) have been emphasized. Not only those issues in our DCS, the Controllability and Observability, but also the hazard-proof abilities vs the parasitic stray capacitive coupling anywhere especially inside each device in analog interface circuits have to be taken into consideration for our analog-DfT requirement. A computer program based on the method has been made and tested for its efficiency and capability.
Intelligent pump test system based on virtual instrument
Jungong Ma, Shifu Wang, Zhanlin Wang
The intelligent pump system is the key component of the aircraft hydraulic system that can solve the problem, such as the temperature sharply increasing. As the performance of the intelligent pump directly determines that of the aircraft hydraulic system and seriously affects fly security and reliability. So it is important to test all kinds of performance parameters of intelligent pump during design and development, while the advanced, reliable and complete test equipments are the necessary instruments for achieving the goal. In this paper, the application of virtual instrument and computer network technology in aircraft intelligent pump test is presented. The composition of the hardware, software, hydraulic circuit in this system are designed and implemented.
Application of virtual instrument in mechanical shock waveform acquisition and analysis
Jianhua Ye, Chuanri Li
The application of virtual instrument (VI) in mechanical shock waveform acquisition and analysis is introduced in this paper. The requirements for the hardware and software design of this virtual instrument are discussed, according to the characters of mechanical shock waveform. Software is the key part of virtual instrument, which is developed under LabWindows/CVI. The software consists of the driver of the data acquisition (DAQ) card, the graphical user interface (GUI), data acquisition control and data processing. Data processing includes tolerance band calibration and check, shock response spectrum (SRS) analysis. The applications of this instrument are demonstrated on the real mechanical shock waveforms and the analysis results.
Software design of distributed automatic testing system for UAV flight control system
Zhi Zhong, Xin Chen
A software design of a distributed automatic testing system is introduced in this paper, which is used for the flight control system (FCS) of unmanned air vehicle (UAV). The RS485 network is adopted for testing several FCS at the same time in the distributed structure software. In the software, two programming technologies, "multithread" and "knowledge base (KB)" are used. The implement of such key technologies, the entirety design idea and the actual design results of the software are also shown in the paper.
Mechanism with 6 DOF for position and orientation measurement
Xiaoliu Yu, Liuhuo Chu, Yuwan Cen, et al.
This paper shows a new 6-DOF mechanism. It can measure 6 coordinate parameters of the position and orientation of a moving platform. The mechanism is comprised of a serial mechanism for position measurement and a parallel mechanism for orientation measurement. It is dexterous for a redundant DOF and a balancing weight in vertical direction. The parallel mechanism is designed by mechanical synthesis in order to avoid difficulty of forward solution, and the orientation parameters of the moving platform are obtained by analytical expressions. Therefore, the 6-DOF parameter values of a moving platform can be displayed in real time. The workspace of the mechanism is obtained by graphology and analytical method. The measuring error is analyzed by error modeling. The design-parameter values for the architecture of the parallel mechanism are optimized.
Front end interception probability and time based on the passive detection system
Feng Liu, Zhiyong Li, Jianli Han, et al.
In this paper, a special passive detection system is selected, which uses synthesis frequency finding system, analyzing its loose measure system and perfect measure system in all round, giving the simulation result of front end interception probability and interception time. The result denotes that if the perfect measure system guided by the loose measure system, the interception probability is increased by a big margin.
Control Theory and Automation I
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Nonlinear generalized predictive control in a thermal process for batch dyeing
Jianxin Zhang, Benyong Chen, Tingxiu Zhong
Dyeing process is a serious nonlinear process, and can't be accurately controlled by traditional linear control algorithms. Generalized Predictive Control (GPC) based on linear model has good performance and strong robust, thus can be used to tacking the control problems with delay and unmodelled errors such as a thermal process for batch dyeing. In order to apply the good linear GPC to the nonlinear batch dyeing process, we introduce a Nonlinear Generalized Predictive Control (NLGPC) based on the Hammerstein model. The simulation results are given and it is concluded that the NLGPC control gives much better performance than the linear GPC.
Designing adaptive fuzzy controller for nonlinear systems
Bo Zhou, Aiguo Shi, Feng Cai, et al.
The objective of this paper is to achieve model reference adaptive fuzzy control for a nonlinear dynamical system. An adaptive fuzzy autopilot for ship course-keeping is developed. The influence of sea current and wave disturbances on course-keeping performance is also considered as random noises. Simulation results are presented.
Identification and control for a chain boiler combustion system based on neural networks
Xiucheng Dong, Qiang Xu
It is difficult to have good performance for chain boiler combustion control system due to large delay time, varying coal's quality and steam load. A neural network identification method for nonlinear system's delay time is discussed. Using the abrupt mutation resulted from the training error sum square of the real output and the expected output of the network, this method changes the input sample period of the neural network so that it can discriminate the delay time of the nonlinear model. Combining the discrimination of neural network system with long time delay and the control method based on model prediction, it can be applied to control the nonlinear long delay time system with variable parameters or unknown delay time. Simulating with a 10t/h chain boiler model, the results show it has much better advantage of celerity and robustness.
Intelligent plate vibration control using piezoelectric sensors and actuators
Jun Yao
An experimental study for the active vibration control of intelligent structures subject to external excitations using piezoelectric sensors and actuators is presented. A simply supported intelligent plate is used as the controlled structures. A "Quasi-Independent Modal Space Control" technique is presented, attempting to approach, with hardware as simple as possible, the Independent Modal Space Control. Chirp sine citation is used as external excitation. In order to increase the adaptability, the time-domain modal identification technique is incorporated into the controller to real-time update the system parameters. The adaptive effectiveness of the time-domain modal identification technique is tested by fixing an additional mass on the simply supported plate to change its structural properties. The vibration suppression performances of the controller are 5.7 dB and 10.8 dB for the plate with/without the mass subject to a chirp sine excitation, respectively. The experiment progress and results show effectiveness and practicality of the control approach.
NN-based adaptive control for a class of MIMO nonaffine nonlinear systems
Yunan Hu, Youan Zhang
Based on neural network (NN) and robust control, an adaptive controller is developed for a class of MIMO nonaffine nonlinear systems. First, take the Taylor series expansion of the original system in the neighborhood of the operating trajectory. Then estimate the unknown functions of the system using NN. Finally, use robust control to overcome the affects of NN estimated error terms and high order terms of the Taylor series expansion. All the signals in the closed-loop system are proven to be uniformly ultimately bounded (UUB) and the mean square and L_infinite tracking error bounds are given in this paper. The simulation results show the effectiveness of the proposed approach.
Design and application of double-sliding mode variable structure control systems
Yunan Hu, Ye Chen
On the base of double-sliding modes variable structure control theories, new design methods of switching surfaces and changing rules of inputs are analyzed. In a system with unmatched uncertainties, two switching surfaces can be designed separately to guarantee the stability; it is proved that the inputs can trap the state trajectory on the switching surfaces; a more simple changing rules of inputs are used, then the state trajectory will hit one of the switching surfaces alternately, so the switching frequency is reduced. Simulation of a linear model with unmatched uncertainties are given, simulation results show the effectiveness and feasibility of the proposed methods.
Soft computing technology for modeling of greenhouse climate control
Lujuan Deng, Kanyu Zhang, Youmin Gong, et al.
The objective of this paper is present a reasonable system model to set greenhouse daytime optimal temperature thereby to achieve the most net profit. In order to set an optimal tmeperature point in a greenhouse, it is essential to construct plants growth model and calculate the cost of modifying environment. In this paper a soft computing system for greenhouse temperature setting has been developed and integrated. It includes three parts. One is an algorithm depending on the energy consumption of each component of heating and ventilation equipment according to two reasonable formulae. The other is a neural network for forecast the photosynthesis rate of tomato according to light intensity, temperature, CO2 concentration, and LAI. The sample data rooted in TOMGRO. The last part is a GA for searching an optimal temperature setting point in daytime.
Integrated control algorithms for plant environment in greenhouse
Kanyu Zhang, Lujuan Deng, Youmin Gong, et al.
In this paper a survey of plant environment control in artificial greenhouse was put forward for discussing the future development. Firstly, plant environment control started with the closed loop control of air temperature in greenhouse. With the emergence of higher property computer, the adaptive control algorithm and system identification were integrated into the control system. As adaptation control is more depending on observation of variables by sensors and yet many variables are unobservable or difficult to observe, especially for observation of crop growth status, so model-based control algorithm were developed. In order to evade modeling difficulty, one method is predigesting the models and the other method is utilizing fuzzy logic and neural network technology that realize the models by the black box and gray box theory. Studies on control method of plant environment in greenhouse by means of expert system (ES) and artificial intelligence (AI) have been initiated and developed. Nowadays, the research of greenhouse environment control focus on energy saving, optimal economic profit, enviornment protection and continualy develop.
Dynamic inversion fuzzy integration control in high angle-of-attack flight
Aijun Li, Yi Shen, Weiguo Zhang
A method for design of flight controllers that provides desired handling qualities over a wide range of flight conditions is presented. The aircraft considered in this paper is capable of flight at very high angles of attack and has thrust vectoring as well as conventional aerodynamic control surfaces. This paper only considers the longitudinal control. The control design method is to use an inner-loop, dynamic inversion controller and an outer-loop, the main-auxiliary fuzzy controller without quantification. The dynamic inversion controller lienarizes the ptich rate dynamcis ofthe aircraft. However, since model uncertainties prevent exact linearization, there will always be errors associated with this controller. The outer-loop fuzzy controller provides robustness to errors due to the lack of exact cancellation of the pitch rate dynamics by the dynamic inversion controller. In addition, its simulation results are also provided.
Target assignment of simultaneous arrival for UAVs
Jie Xia, Jinyuan Gao
The Extend Hungary Method (EHM) is presented to solve the assignment problem that the number of UAVs is larger than that of targets. The target assignment is modeling and the motivations are minimize the distance of the UAV fleet, maximize the survivability of the UAV fleet, maximize the number of UAVs assigned to each target and maximize the number of target attacked. An algorithm for arriving simultaneously is presented by combination of the EHM. Simulation results demonstrating the feasibility of the approach are presented. The approach could be easily applied into other multi-robot cooperative mission.
CAN bus based traffic signal control system
Yong Liu, Zhongke Shi, Wuyuan Su
The article is focused on the fault-tolerant communication between the monitor computer and traffic signal machines, which based on the XATM-IV traffic signal control system designed by Air Traffic Management Institute of Northwestern Polytechnic University (NPU). As a popular field bus, CAN bus is adopted here to achieve above communication because of its high reliability and anti-interference ability. The design of hardware and software of CAN bus are introduced in the paper in details. At the last, some methods of fault-tolerant technique have been discussed and an efficient method is given out.
UAV flight path preview control technology
Zhengxiang Qian, Lizhi Qian, Leiping Xi, et al.
This paper aims at solving the deficiency of flight-path control system of Unmanned Aerial Vehicle (UAV). On the basic of analyzing the problems of flight-path control technology of UAV, this paper uses the updated automation technology -- digital preview control theory as flight path optimizing measures, and establishes flight path optimizing model of UAV to have simulation analyses. It can improve UAV with higher mobility and rapid reaction capability, so it has important application value in army.
Stability of control systems with variable time-delay
Rudolf Tracht, Marc Thorausch
In modern automated systems decentralized concepts are used. Information is communicated via networks as for instance fieldbus systems or industrial ethernet. Since often many users access to the bus, communication time is varying. In most cases this is not critical but for some aplications stability problems are introduced by the varying time-delay. Such applications can be modeled by control loops with a time varying delay block. Different methods were proposed in the last two years for analyzing control systems of this type. Usually state space models are investigated and linear matrix inequalities (LMI) must be solved. The stability region depends not only on the value of the delay time but also on the time-derivative of the variable delay-time. In the paper a new approach for analyzing stability is presented: The control system with delay is considered in the frequency domain. A stability criterion for systems with periodic varying time-delay is derived. By using a suitable transformation more general delay systems can be investigated. The method is illustrated by an example and simulation studies.
Analysis of universal-logics-based fuzzy neural networks
Bin Lu, Huacan He
To improve the inference performance of fuzzy neural networks (FNN), this paper presents a new type of FNN where the Universal Logics are employed, which makes it possible to enhance the performance of FNN not only by tuning the shapes of the membership functions, but also by tuning the parameters of the fuzzy inference structure. Finally, the simulation result in process control proves its effectiveness.
Fuzzy decoupling controller based on multimode control algorithm of PI-single neuron and its application
Xianxia Zhang, Jian Wang, Tinggao Qin
Intelligent control algorithms are introduced into the control system of temperature and humidity. A multi-mode control algorithm of PI-Single Neuron is proposed for single loop control of temperature and humidity. In order to remove the coupling between temperature and humidity, a new decoupling method is presented, which is called fuzzy decoupling. The decoupling is achieved by using a fuzzy controller that dynamically modifies the static decoupling coefficient. Taking the control algorithm of PI-Single Neuron as the single loop control of temperature and humidity, the paper provides the simulated output response curves with no decoupling control, static decoupling control and fuzzy decoupling control. Those control algorithms are easily implemented in singlechip-based hardware systems.
Studies on the stability of a class of hybrid systems
Yongji Wang, Quanmin Zhu
The closed loop stability of a class of hybrid system is studied, which is described by a linear discrete ARMA model and an integration equation. This problem is brought frequently from the controller design based optimization of some integration performance index. Several sufficient conditions for stability are derived. And an example for probability density function control is given for demonstration.
New method for the autonomous celestial navigation of lunar explorer based on the unscented Kalman filter
Jiancheng Fang, Yu Zhang
Celestial Navigation is a completely autonomous navigation method for spacecraft. When the Extended Kalman filter is applied to the autonomous celestial navigation, the state and measurement equations need to be linearized. The precision of the estimation isn't fine because of the truncated error of the high-order items introduced by linearization. Unscented Kalman filtering is a new method aimed at nonlinear systems. It is applied to the autonomous celestial navigation of the lunar explorer in this paper, and the simulation is studied based on the Cartesian coordinates. The results demonstrate that the characteristic of the Unscented Kalman filtering is superior to the Extended Kalman filter.
Practical criteria for robust stabilizing of dynamic discrete interval systems
Jinfang Han, Zhonghui Xue, Jiqin Peng
In this paper, the Robust-stabilizing for a kind of dynamic discrete interval systems are investigated by means of the theory of matrix and real numbers. The ideas of schur-, asymptotic-, Robust-stabilizing, and mixed stable type are introduced, and two core theorems for the stability and mixing stability which are different from the existing literatures and an important proposition are presented. On the basis of these three main criterions, several simple practical criteria for the Robust-stabilizing are obtained.
Design and analysis of fuzzy controllers with amending factor
Xiaoqin Lian, Zhiguo Cao, Ming Xie
In this paper, a fuzzy controller with amending factors is proposed and illustrated through a specific example. And the control effects with respect to different number of amending factors are compared. The results show the superior performance of the fuzzy controllers with amending factors because of the adaptive regulation of the fuzzy inference rules according to the error.
Fuzzy neuron variable structure control for a direct-drive manipulator
Jianming Zhang, Ning Wang, Shuqing Wang
Based on the neuron model and its learning strategy proposed in reference one, the fuzzy neuron variable structure control method is proposed in this paper. In this variable structure control system, the fuzzy controller speeds up the transient response when the system error is big and the neuron controller eliminates the steady state error of the system by utilizing the associate learning algorithm. To the independent joint of direct-drive manipulator, the control experiments are made. The results show that this model-free controller has good performance.
Design methodology of magnetorheological fluid damper using Herschel-Bulkley model
Linqing Liao, Changrong Liao, Jianguo Cao, et al.
Magnetorheological fluid (MR fluid) is highly concentrated suspension of very small magnetic particle in inorganic oil. The essential behavior of MR fluid is its ability to reversibly change from free-flowing, linear viscous liquids to semi-solids having controllable yield strength in milliseconds when exposed to magnetic field. This feature provides simple, quiet, rapid-response interfaces between electronic controls and mechanical systems. In this paper, a mini-bus MR fluid damper based on plate Poiseuille flow mode is typically analyzed using Herschel-Bulkley model, which can be used to account for post-yield shear thinning or thickening under the quasi-steady flow condition. In the light of various value of flow behavior index, the influences of post-yield shear thinning or thickening on flow velocity profiles of MR fluid in annular damping orifice are examined numerically. Analytical damping coefficient predictions also are compared via the nonlinear Bingham plastic model and Herschel-Bulkley constitutive model. A MR fluid damper, which is designed and fabricated according to design method presented in this paper, has tested by electro-hydraulic servo vibrator and its control system in National Center for Test and Supervision of Coach Quality. The experimental results reveal that the analysis methodology and design theory are reasonable and MR fluid damper can be designed according to the design methodology.
Application of PLC in digitization control intelligence can-body high-speed resistance welding machine
Shaobo Chen, Ziqiang Zhang, Qiusheng Yan, et al.
The application of position servo synchronously tracking system constituted with PLC and general AC servo system in digitalization control intelligence can-body high-speed resistance welding machine is introduced in this paper. By studying the digitalization control system of automatic can-body resistance welding machine, technologic upgrade of product is made, and application of PLC in controlling general AC servo motor multi-axes ganged system to replace conventional mechanical ganged mechanism is developed. It makes the coordination of movements between machine actions can be ensured and every correlative actions can quickly and precisely run synchronously, quondam mechanical branching driving can be replaced, and "mechanical locking" between quondam movements can be changed to the "electronic locking," complex mechanical structures such as cams, stepless speed changing machines and universal joints and so on can be omitted, so the working capability of whole machine can effectively be enhanced and synchronization between the machine actions can rapidly be reached. The application realizes digitalization process control, enhances reliability, stability and manufacturing efficiency of the machine, and reduces the manufacturing cost.
Control Theory and Automation II
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Extraneous torque and compensation control on the electric load simulator
Zongxia Jiao, Chenggong Li, Zhiting Ren
In this paper a novel motor-drive load simulator based on compensation control strategy is proposed and designed. Through analyzing the torque control system consisting of DC torque motor, PWM module and torque sensor, it is shown that performance of the motor-drive load simulator is possible to be as good as that of the electro-hydraulic load simulator in the range of small torque. In the course of loading, the rotation of the actuator would cause a strong disturbance torque through the motor back-EMF, which produces extraneous torque similar as in electro-hydraulic load simulator. This paper analyzes the cause of extraneous torque inside the torque motor in detail and presents an appropriate compensation control with which the extraneous torque can be compensated and the good performance of the torque control system can be obtained. The results of simulation indicate that the compensation is very effective and the track performance is according with the request.
Structure and algorithm for a type of predictive control
Suying Zhang, Zhifeng Pang
In this paper, it is proposed that the predictive control based on fore-feed structure and its algorithm. This way can effectually improve the dynamic quality of system with the pure time delay in the case of disturbance acting. For the predictive control algorithm, it is introduced the concept for the statistics probability when the forecast occurrence and the cost factor. In the Engineering application, the key step is that aiming at the concrete object to look for the statistics probability and the cost factor.
Parameter calculation of brushless direct current motor in attitude control and energy storage flywheel application
Yanliang Xu, Gang Liu, Jian-cheng Fang
Permanent magnet brushless direct current motor (BDCM) used in attitude control and energy storage flywheel system features large air gap and large radius-to-length ratio. The air gap flux density of this kind of DBCM along circumference orientation and axis one is analyzed. Equivalent flux leakage coefficient and equivalent flux density calculating coefficient are brought about and calculated in order to design the motor conveniently. The presented results are verified by prototype experiment.
Design of control network based on OMRON PLC
Xiaocheng Wang, Xiangli Song, Yuan Liu, et al.
This paper briefly introduces the design of control network based on OMRON PLC; and describes in detail step and setting of design based on three kinds of network: Ethernet, controller link and CompoBus/D. The design has been applied to lab construction. The practice shows that it is valuable for teaching and scientific research.
PWM power amplifier with PD correction for magnetic suspending flywheel
Liang Zhang, Jiancheng Fang
The power amplifier is a primary component in the control system of the magnetic suspending flywheel, which has to supply the electromagnet coil current proportional to an input voltage signal to generate the required magnetic field force. In this paper, a Pulse Width Modulated (PWM) switching power amplifier with a necessary Proportional Differential (PD) correction circuit is designed for the control system of the magnetic suspending flywheel. The experimental results shows that PWM power amplifier with PD correction features high efficiency, low signal distortion, broad bandwidth, and wide linear range and can meet the requirement for the control system of the magnetic suspending flywheel.
Nonlinear adaptive control systems design of BTT missile based on fully tuned RBF neural networks
Yunan Hu, Yuqiang Jin, Jing Li
Based on fully tuned RBF neural networks and backstepping control techniques, a novel nonlinear adaptive control scheme is proposed for missile control systems with a general set of uncertainties. The effect of the uncertainties is synthesized one term in the design procedure. Then RBF neural networks are used to eliminate its effect. The nonlinear adaptive controller is designed using backstepping control techniques. The control problem is resolved while the control coefficient matrix is unknown. The adaptive tuning rules for updating all of the parameters of the fully tuned RBF neural networks are firstly derived by the Lyapunov stability theorem. Finally, nonlinear 6-DOF numerical simulation results for a BTT missile model are presented to demonstrate the effectiveness of the proposed method.
Optimal design of open-and-close-loop PID-type ILC algorithm
Jinxue Xu, Lili Sun, Tianyou Cai
Iterative learning control (ILC for short) is a simple and effective method for the control of systems that perform the same task repetitively. ILC algorithm uses the repetitiveness of the task to track the desired trajectory. In this paper, we assume that a measured finite impulse response series of the plant to be controlled are available. We propose an optimal design method of PID (proportional plus integral and derivative tracking error) type ILC update law, and a current cycle error assisted open ILC scheme is presented which is also called open and close loop PID type algorithm. By adding close loop scheme, the whole algorithm has better performance both in stability and convergence than the open loop one alone. The using of current iteration tracking error (CITE) also helps to get faster convergence rate. Furthermore, the effectiveness of the proposed method is illustrated by introducing some simulation experiments.
Coupled pitch and velocity control of a doubly fed linear motor
Bo Yang, Michael Meyer, Grotstollen Horst
This paper proposes a new coupled pitch and velocity control of a doubly-fed linear motor, which is applied for a novel mechatronic railway system based on the operation of shuttles. Compared with conventional trains, a single axle under-carriage is developed for the shuttle. The primary of the linear motor is installed between the rails and the secondary is fixed on the axle only via the middle. In order to prevent the secondary from pitching and maintain a constant air gap between the primary and the secondary, the secondary windings are divided into two parts to be supplied separately. A decoupled pitch and velocity control is introduced in reference one in detail. Because the currents for pitch control don't contribute to velocity control. They cause higher power losses of the system. Therefore, a coupled pitch and velocity control is developed and presented in this paper.
A new design method of magnetic bearing
Yanliang Xu, Gang Liu, Jiancheng Fang
The effect of bias current on the performance of magnetic bearing (MB) is studied. The design procedure of MB is given, which is divided into such two steps as the original one when ignoring the core magnetic circuit and the checkout one when not ignoring the core magnetic circuit. The effectiveness of this method is verified by the prototype MB design.
Large maneuverable flight control using neural networks dynamic inversion
Enquan Yang, Jinyuan Gao
An adaptive dynamic-inversion-based neural network is applied to aircraft large maneuverable flight control. Neural network is used to cancel the inversion error which may arise from imperfect modeling or approximate inversion. Simulation results for an aircraft model are presented to illustrate the performance of the flight control system.
Research of autonomous landing control of unmanned combat air vehicle
Shaoyan Li, Zongji Chen
This paper is to present a robust controller design method for developing autonomous landing systems of Unmanned Combat Air Vehicle (UCAV). We first analyze the characteristic of autonomous landing of UCAV, and put forward its landing performance specifications. Structure singular value μ| synthesis is used to develop autonomous landing systems to accurately follow the pre-designed ideal landing track or online generated optimal landing track. The robust performance of system is analyzed. The simulation results demonstrate that the designed autonomous landing system satisfies the performance requirements of autonomous landing of UCAV when there are uncertainties of UCAV aircraft model, measurement noises and exogenous disturbances.
Application of formal methods to fault-tolerant flight control systems
Le Xue, Zongji Chen
This paper is concerned with the application of formal methods to fault-tolerant flight control systems. The analysis, design and verification of a fault-tolerant flight control system have been performed in the theoretical framework of the extended duration calculus, which is a popular formal method to handle highly complex real-time hybrid systems. The theoretical results in this paper show that the proposed approach can ensure the flight control system to work properly even after a fault happens.
Robust adaptive control of a class of nonlinear systems
Maobing Wang, Chen Wei
Robust adaptive control of a class of discrete-time parametric-strict-feedback nonlinear systems is studied. The control law is designed based on gradient algorithm with dead-zone and on recursive adaptive predictors. Global stability and tracking performance are established for the closed-loop systems.
Neural network control of magnetic bearing
Junru Wang, Benyong Chen, Zhengrong Sun, et al.
The realization and capability of magnetic bearing principally depends on the design of controller. It is difficult to induce its precise mathematic model because the magnetic bearing has complex non-linearity. The classical PID control method focus on systems having precise mathematic models. The neural network control method does not need the precise mathematic model, and has entirely different information processing approach compared to the classical PID control. The neural network, based on the principles of self-adaptive and being-trained, has self-study capability, so it adapts to controlling a magnetic bearing system. In this paper, we simulate both the neural network PID control algorithm and the classical PID control algorithm with the disturbances of output force exist, and conclude that the neural network PID control is superior to the classical PID control in respect of adjusting time and overshooting values.
A neuron model-free controller with fuzzy tuning gain for continuous steel casting processes
Ning Wang, Feng Xu, Zifen Xie
The continuous steel casting is an important link in steel production. The performance of mold level control for the continuous steel casting affects the steel quality directly. The main difficulties for mold level control are that the continuous steel casting has big uncertainties and grave nonlinearities, and the continuous steel caster runs in its hot and hostile environment. In this paper, the neuron model-free control method with fuzzy tuning gain is proposed for continuous steel casting processes. In this control system, the neuron controller is used to control the mold level and the fuzzy algorithm to tune controller gain. According to the system operation conditions, the fuzzy rule base is updated to improve control performance. The experiments are made to demonstrate the effectiveness of the proposed controller.
Research of intelligent control method for the temperature of fermentation
Dongqing Feng, Minrui Fei, Tiejun Chen, et al.
Fermentation process of the microorganism is a comprehensive course of organism growth and chemical reaction and the fermentation temperature is one of its most important parameters. Though an analysis of the fermented mechanism, this paper has introduced an intelligent control method for the fermentation temperature based on the apery intelligent control algorithm. During control processes, the function of human's control behavior is mimiced by the computer, and the characteristic information obtained from the dynamic processes of the control system is fully used to analyze, judge and decide so that the effective control of the object lacking of accurate model can be made. The system that adopted the apery intelligent control algorithm has been applied to a bio-pharmaceutical enterprise and has achieved a satisfied result.
Model-free neural control of a class of nonlinear plants
Zhong Zheng, Ning Wang
In this paper, a model-free neural controller for a class of nonlinear plants is proposed. Based on the neuron model and its learning strategy for control in reference one, the nonlinear neurocontrol method is designed. After discussing the relationship between the controller gain and the nonlinear system error or error change, the nonlinear function is used to construct the neural network model and the inputs are selected to meet control demands of nonlinear plants. To show the efficiency of the proposed controller, simulation results for the fluid level control in a spherical tank are presented.
Fuzzy control system for oil volume of heating furnace
Zhonghui Xue, Xuedong Liu, Lei Wang, et al.
This paper presents the methods such as controlling oil volume by combining fuzzy control with PID control, PID parameter with intelligent fuzzy self-adjusting, and solving delay problems by using forecast control. Through measuring the performance of the heating furnace, the control algorithms are continuously adjusted, and the coordination factors are changed and become to be intelligent. On the other hand, the wind volume is controlled through fuzzy control with self-seeking optimization. So the burning of the heating furnace can reach optimum. These methods make the control system produce better dynamic response and higher stability. In this way it either reduces cost or increases product quality. It is confirmed that these methods are practicable and effective. They are good intelligent control methods. These methods have been used in the control system of heating furnace in Tangshan Iron and Steel Company, and the better control effects have been obtained. Finally, the real control effect curve before and after using these methods is given.
Intelligence coordination control system for complicated industrial process based on LAN
Yun Du, Hua Meng, Xueli Wu, et al.
In this paper a new type of intelligence coordinate control system used in complex industrial processes is proposed: it bases on management information system LAN and comprises of artificial intelligence, expert system, and fuzzy neural network control. It can realize the integration of management and control, and provides an effective solution to complex industrial processes system. Simulation and control experimentation show control index is satisfactory. The system has been used in a steelworks converter control system.
A phase-leading compensation method used to control nutation of magnetically suspended rotor in control moment gyroscope
Tong Wei, Jiancheng Fang
Referring to rigid rotor with remarkable gyroscopic effect, nutation at high rotational speed is unstable if phase lag exists in decentralized controller of magnetic bearing system. Based on radial kinematic model of the rotor and root-locus, this paper analyzes the relation between nutation stability and system phase lag. Then a simple phase-leading compensation method based on nutation track prediction is proposed. Simulations and experiments show this method can compensate phase lag with regard to nutation control and thus can improve system stability effectively.
Model-following adaptive second-order sliding model control of a class of nonlinear uncertain systems
Anli Shang, Wenjin Gu
In this paper, a novel algorithm model-following adaptive second-order sliding model control is proposed for a class of nonlinear uncertain systems. Second-order sliding model control can effectively counteract chattering that conventional sliding model control hold. The difference between the output of pant and the output of the followed model is regarded as sliding variable; the algorithm presented here introduced a suitable commutation logic that prevents uncontrollable growth of the uncertainties in the control system. Thank to this algorithm, the nonlinear uncertain systems are properly controlled. The example of simulation shows that the method is very effective for a class of nonlinear uncertain systems, and can be used in real time online control.
Modeling and Simulation
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Enabling distributed hardware-in-loop simulation for aircraft utilities management system
Juan Chen, Qiaozhen Liu, Zhanlin Wang, et al.
The utility systems of an aircraft are classed as what related to the control of the basic aircraft electro-mechanical systems. Traditional utility subsystems have developed their own set of mechanical and analog controls as part of their systems, which cause the insufficient use of hardware, congested cockpit and pilots' over-workload. The distributed utility simulation platform supplies common simulation environment for integration design and evaluation of the aircraft utility systems. The simulation platform for integrating hardware and software is based on multi-processors connected to dual redundant data bus. Design engineers can fulfill the study of integrating multiplex utility subsystems and carry out synthesis management and efficient organization of the utility systems. On the platform, the subsystems not only can implement their dedicated functions, but also have the ability of redundancy, fault-tolerance and reconfiguration. The platform supports for both digital and hardware-in-the-loop simulation and offers right-hand simulation and demonstrating tools for the integration design of the aircraft electro-mechanical systems.
Research based on the CAN-bus-based simulation platform of novel redundant flight control system
Zhiyong Tang, Zhanlin Wang, Lihua Qiu
This paper proposes a redundant flight control system task based on the basis of task segment, task schedule and task supervision, analyzes the task scheduling based on CAN bus, and proposes the overall task-scheduling strategy of static allocation and dynamic scheduling. Further more, the multi-group genetic simulated-annealing algorithm is adopted to realize the static allocation, namely, the Boltzmann mechanism of simulated annealing is introduced into the reception process of new individuals. And the dynamic scheduling algorithm is discussed for the nodes that are in both normal and abnormal conditions. The conclusion points out that this system has better real-time performance, reliability and fault tolerance.
Ocean wave simulation in VR applications
Jie Ma, Ju Cao, Jinwen Tian, et al.
This paper presents a new method to simulate virtual ocean wave surface. One of the widely used methods for simulating ocean wave is making use of wind-wave spectrums, which is mostly based on linear wave theories. The ocean waves produced in this way can reflect the statistical characteristics of the real ocean well, on the other hand the waves does not look like actual ocean surface, they just look like superposition of sine/cosine curves. In order to overcome this shortcoming of traditional method, the new method proposed in this paper take account of the effect of the random wind velocity field over ocean surface. In practice, this method can simulate the natural environment of ocean more accurately than traditional method; in theory, the method increases the nonlinear factors of ocean waves. The virtual ocean wave simulated by this way is not only accord with statistical characteristics, but also looks like real ocean wave, it can be widely used in VR applications.
Cosimulation of embedded system using RTOS software simulator
Shihao Wang, Zhigang Duan, Mingye Liu
Embedded system design often employs co-simulation to verify system's function; one efficient verification tool of software is Instruction Set Simulator (ISS). As a full functional model of target CPU, ISS interprets instruction of embedded software step by step, which usually is time-consuming since it simulates at low-level. Hence ISS often becomes the bottleneck of co-simulation in a complicated system. In this paper, a new software verification tools, the RTOS software simulator (RSS) was presented. The mechanism of its operation was described in a full details. In RSS method, RTOS API is extended and hardware simulator driver is adopted to deal with data-exchange and synchronism between the two simulators.
Research on measurement and modeling of micro-inertial-measurement unit
Jitao Teng, Yandong Wang, Xianfang Sun, et al.
Rate calibration and six position calibration tests are discussed about a kind of micro inertial measurement unit (MIMU). A simple mathematical model of micro gyroscope and accelerometer is designed, some model parameters such as bias, scale factor, cross-axis coupling factors etc are confirmed. The effect of the model compensation is checked by the real tests. The tests result shows that gyroscope drift error compensated is near 0.01 o/s, the accelerometer error is below 10-3 g, the precision of MIMU is highly improved after error compensation, and the mathematical model is simple and the speed of calculation is also high.
Fuzzy neural networks based on rough sets for process modeling
Jianming Zhang
A new constructive method of the fuzzy neural network based on rough sets is proposed. First, we generate an initial fuzzy rule base from the history input-output data pairs. Then, in order to obtain the optimal rule base, the inconsistent or redundant rules of the initial fuzzy system are reduced by means of the rough set theory. Finally, we implement an optimal and simple fuzzy neural network by mapping from the optimal rules and train it with the initial data pairs. Since we determine the proper network structure and initial weights in advance, we can train the fuzzy neural network rapidly. The application to modeling of a nonlinear process reveals that it is effective and has good performances. The merit of this new method is to optimize the overall structure of fuzzy neural networks as well as to adjust each parameter of fuzzy rules without doing the complicated clustering process.
Research on C4I simulation in distributed simulation system
Ning Li, Guanghong Gong, Xiaoyuan Peng
This paper discusses components and architecture framework of C4I simulation system under distributed simulation environment. Combined with a typical example of distributed simulation system, two schemes of C4I simulation system are brought forward, which are based on different architecture: HLA and user-defined LAN communication protocol. Their characteristics are analyzed and their advantages and disadvantages are also compared. Some key technologies such as developing Federation Object Model (FOM) of complex distributed simulation system, information fusion, real-time transmission of communication and intelligence message and C4I oriented synthetic display of multi-dimensional Information etc. are discussed.
Design of an AR-based virtual painting system: AR-painter
A dynamic Augmented Reality (AR) system, AR-PAINTER, is presented in this paper, which is an indoor, real-time and multi-user system for painting virtual textures and images to the surface of a real object. The system is designed with a vision-based algorithm, which tracks markers of special features on the real object for the purpose of registration. The registration algorithm and the generation of virtual image are discussed. The experimental results are also presented and the results validate the feasibility of the proposed AR system in other applications.
Development of a distributed real-time air combat simulation system
Jianliang Ai, Zhiwen Li
The development of a distributed real-time air combat simulation system is described. The objective of the work is to provide a high-fidelity platform based on PC for air combat researches. The complete system is designed to be made up of three layers known as the data layer, the service layer, the application layer to reduce the modeling complexity and maintain the opening of the system. Precise mathematical models have been established for all critical sub-systems and processes in air combat simulation. Basic flight and air combat simulation has been tested on the system and proved its accuracy and high cost-effectiveness. The modularity of the system makes it easily adaptable to the analysis of other technologies and thus be of potential use.
Hardware-in-the-loop simulation and testing of digital engine control system
Tao Cheng
This paper covers the hardware and software configuration of Hardware in the loop simulation (HILS) testing of minitype aero turbine engine control systems, their interconnections and general method followed in testing. Some of the practical aspects of real time simulation, interfacing, procedure for closing the loop and typical test results are presented. Dynamic simulation tests on the actual hardware and control software of the engine control system in conjunction with real time software model of the engine are carried out. The tests correct and verify the transient and steady state performance of the engine control system. Hardware in the loop simulation tests complete the verification and evaluation of the capability of engine ground start, steady state, accelerating and decelerating regulation. Also the tests evaluate the integrated control capability of engine control system in the flight envelope.
Both-branch fuzzy logic II
Gang Liu, Yanliang Xu, Jian-hui Zhao, et al.
On the basis of both-branch fuzzy sets, the paper builds up the study frame of both-branch fuzzy logic, which is reasonable extension for single-branch fuzzy logic. Proceeding with both-branch proposition, the paper provides the characteristics of both-branch fuzzy logic, Disjunctive Normal Form and Conjunctive Normal Form.
Working operation problem based on DNA computing
ZhiXiang Yin, Shuangqing Tang, Yafei Dong, et al.
Over the past few years, a handful of insightful researchers have get a new method of computing-DNA computing. DNA computing is a novel method based on bio-chemistry. Since Adelman solved Directed Hamilton Path by encoding and molecular-biological manipulations in 1994, DNA computing have become an attractive field. In the paper, we solve a famous problem (working operation problem) of operation research based on Adelman'S approach. This work represents further evidence for the ability of DNA computing to solve NP-complete search problems.
Multimode marine engine room simulation system based on field bus technology
Huayao Zheng, Linlin Deng, Yi Guo
Developing multi mode MER (Marine Engine Room) Labs is the main work in Marine Simulation Center, which is the key lab of Communication Ministry of China. It includes FPP (Fixed Pitch Propeller) and CPP (Controllable Pitch Propeller) mode MER simulation systems, integrated electrical propulsion mode MER simulation system, physical mode MER lab, etc. FPP mode simulation system, which was oriented to large container ship, had been completed since 1999, and got second level of Shanghai Municipal Science and Technical Progress award. This paper mainly introduces the recent development and achievements of Marine Simulation Center. Based on the Lon Works field bus, the structure characteristics and control strategies of completely distributed intelligent control network are discussed. The experiment mode of multi-nodes field bus detection and control system is described. Besides, intelligent fault diagnosis technology about some mechatronics integration control systems explored is also involved.
New histogram-based BIST scheme for on-board ADC
Yunan Hu, Liang Wu
A Histogram-based On-Board ADC BIST method is presented in this paper. Compared with the classical Histogram test, this scheme reduces the BIST hardware cost greatly, because the difficulty of nonlinearity computation is reduced in our scheme. Instead, we set a threshold to justify the nonlinearity of the ADC under test.
Practical calibration methods for VXIbus instrumentation
Zhanbao Gao, Xingshan Li
With the VXIbus instrumentation being widely used, it has been made clear that the instrument calibration is necessary. But VXIbus instrument calibration has not been addressed by the VXIbus Consortium. This paper gives a kind of practical calibration method for the end users. As an example, the calibration for Agilent E1418A is described in detail. A calibration foundation system for VXIbus instruments is built and its calibration software is developed. This kind of calibration method has been proven to be useful and effective in the end user's application.
Vibration environment simulation controller
Hongjie Yuan, Chuanri Li
Vibration environment is one of most important environmental factor that may cause product failure. The simulation of vibration environment in laboratory is very necessary. This paper describes a vibration controller that can simulate vibration on electro-dynamic and hydraulic shakers. The vibration is generated according to the test profile by electromagnetic or hydraulic shaker. The test profile is defined in shock waveform, random PSD, sine, or sine on random. The controller is a computer-aided-test system. By compensating the dynamic behavior of the shaker system, fixture and test items, it can replica vibration environment to meet the demand of test profile. The control strategy and software implementation of the controller are presented in this paper.
xPC-target-based rapid prototyping of magnetic bearing digital control
Kai Xiao, Wen Li, Kun Liu, et al.
The control system of magnetic bearing is a complex system. A digital controller is suitable for implementation of advanced control algorithms and easy to adjust control parameters. First, we analyze the principle of magnetic bearing, then by using xPC Target in MATLAB environment, we construct rapid prototyping of magnetic bearing digital control, this help us to solve the problem of simulation and realization. The methods can be used as guidelines for other real-time control system designers.
Simulation on a novel SOI optical waveguide directional coupler
Kezu Zhou, Wensheng Wei, Chunxi Zhang
A novel optical waveguide directional coupler based on SOI (Silicon on Insulator) was designed, its power split ratio and insertion loss was calculated, respectively. The relation between its optical properties and geometrical parameters (such as the width, thickness, bend radii) were discussed. After simulating, the parameters of this SOI optical waveguide directional coupler were optimized.
Operational model of magnetorheological transmission
Jingnan Liu, Hongyu Shu, Aitao Tang, et al.
Magnetorheological (MR) transmission transmits the torque by the shear stress of the MR fluids. In this paper, the operational Model of MR fluids transmission is investigated theoretically. Bingham model is used to describe the properties of the MR fields. Based on the direct shear operational mode, the transmission modes of the MR fluid between two parallel plates, two circular plates and two circular plates are analyzed respectively. The expressions of the force and the torque developed by the shear stress of MR fluids in these transmission modes are derived. The research results show that the MR fluids can be used in transmission. The torque increases as the applied magnetic field strength increase.
Modified target recognition based on rough sets
Xianpei Wang, Yalin Chen, Zheng Y. Dai, et al.
In this paper we present a modified target recognition data fusion module. Knowledge filter and knowledge reconstruction based on Rough sets optimize the knowledge acquisition, simplify the following inference machine's structure and reduce the complexity of calculation. The blackboard frame makes the mutual expert systems cooperate well. The method had been used in fault diagnosis of water turbogenerator in fire-power-plant and wined the satisfactory effect.
Artificial Intelligence and Fault Detection
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Framework for robot skill learning using reinforcement learning
Yingzi Wei, Mingyang Zhao
Robot acquiring skill is a process similar to human skill learning. Reinforcement learning (RL) is an on-line actor critic method for a robot to develop its skill. The reinforcement function has become the critical component for its effect of evaluating the action and guiding the learning process. We present an augmented reward function that provides a new way for RL controller to incorporate prior knowledge and experience into the RL controller. Also, the difference form of augmented reward function is considered carefully. The additional reward beyond conventional reward will provide more heuristic information for RL. In this paper, we present a strategy for the task of complex skill learning. Automatic robot shaping policy is to dissolve the complex skill into a hierarchical learning process. The new form of value function is introduced to attain smooth motion switching swiftly. We present a formal, but practical, framework for robot skill learning and also illustrate with an example the utility of method for learning skilled robot control on line.
Development of a 3-DOF in-parallel compliant micromotion stage for micromanipulation
Jingjun Yu, Shusheng Bi, Guanghua Zong
This paper addresses the design and control issues of a novel micromanipulator which uses a 3-DOF parallel compliant mechanism driven by PZT actuators. Based on the pseudo-rigid-body model of the mechanism, both its conceptual design considerations and the final prototype are outlined first. In order to achieve a fine close-loop control for the PZT, a control law called Variable Speed Integral PI with Switched Parameters is employed based on a simplified but effective dynamic model of PZT actuators. Results from performance testing of the prototype compliant micromanipulator demonstrate that it has repeatability with less than 1 micron. The compliant stage is used as a high-precision bioengineering-oriented micromanipulator.
Improving selectivity of infrared gas analyzer with neural network
Yonghuai Zhang, Junhua Liu
Present applied research on how to improve selectivity of dispersive infrared gas analyzer (DIGA) is mostly confined to the improvement of hardware techniques with new structure, material and technology, which have insoluble deficiencies when non-aim gases bring forth cross absorption during the characteristic absorption spectrum of gas to be measured. The arithmetic of BP neural network can be used to eliminate the cross-interfere absorption and consequently improve selectivity of DIGA. When detecting methane in petroleum fission gas, measuring gas methane measurement scale is 0 to approximately 7600 x 10-6 and interfere gas ethene concentration varies 7600 X 10-6. After using neural network data fusion, the selectivity index of DIGA can be increased from 3.17 to 422 and the relevant fluctuation error of main sensor output decreased from 57.9% to 0.65%. The experimental result indicates the method has practical application value.
Novel probabilistic neuroclassifier
Jiang Hong, Gursel Serpen
A novel probabilistic potential function neural network classifier algorithm to deal with classes which are multi-modally distributed and formed from sets of disjoint pattern clusters is proposed in this paper. The proposed classifier has a number of desirable properties which distinguish it from other neural network classifiers. A complete description of the algorithm in terms of its architecture and the pseudocode is presented. Simulation analysis of the newly proposed neuro-classifier algorithm on a set of benchmark problems is presented. Benchmark problems tested include IRIS, Sonar, Vowel Recognition, Two-Spiral, Wisconsin Breast Cancer, Cleveland Heart Disease and Thyroid Gland Disease. Simulation results indicate that the proposed neuro-classifier performs consistently better for a subset of problems for which other neural classifiers perform relatively poorly.
Evidential reasoning research on intrusion detection
Xianpei Wang, Hua Xu, Sheng Zheng, et al.
In this paper, we mainly aim at D-S theory of evidence and the network intrusion detection these two fields. It discusses the method how to apply this probable reasoning as an AI technology to the Intrusion Detection System (IDS). This paper establishes the application model, describes the new mechanism of reasoning and decision-making and analyses how to implement the model based on the synscan activities detection on the network. The results suggest that if only rational probability values were assigned at the beginning, the engine can, according to the rules of evidence combination and hierarchical reasoning, compute the values of belief and finally inform the administrators of the qualities of the traced activities -- intrusions, normal activities or abnormal activities.
Hopfield-neural-network-based filter design for INS/DS integrated navigation system
Long Zhao, Zhe Chen
While INS (Inertia navigation system)/DS (Double-star) integrated navigation system is implemented using Kalman filtering technology the filtering performance is unsatisfactory, because the model error of DS system is unknown and the stability is not good, either. The novel method for state estimation, based on Hopfield neural network, is presented, and is defined as Hopfield-estimation. The mathematical model for INS/DS position integrated navigation system is set up. The state optimal estimation is obtained by minimizing the energy function of the Hopfield neural network in this scheme, and the statistic information for the model error and the observation noise is not required. Simulating experimentation is implemented using practical measurement data of the INS and DS. Simulation results show that the Hopfield state estimation method performs much better than the Kalman filtering in the same simulation conditions.
Influence of electromechanical loading on mechanical characterization of piezoelectric stack actuator
Kai Zheng, Shaoze Yan, Shizhu Wen
The response of piezoelectric stack actuator under electric, mechanical, and electro-mechanical loading was investigated. Some parameters were evaluated, including output displacement, hysteresis, output force and mechanical stiffness as a function of mechanical preload and electric field value representative of in-service conditions, to understand the behavior of piezoelectric stack actuator under the combined electro-mechanical loading, and to determine the design-oriented fundamental information. Initially, the output displacement is enhanced with the increase in mechanical preload and the maximum displacement values are obtained when the stacks are preload between 6 - 8 MPa. The hysteresis degree under certain preload has better performance. Stiffness measurements indicate strong dependence on mechanical preload and applied voltage, and the values change significantly depending on the operating conditions. The output force results showed that the external mechanical compress did not have significant influence.
Recognition of similar handwritten Chinese characters based on support vector machines and partial space method
Jun Feng, Yang Yang, Xianmei Wang, et al.
This paper presents a recognition approach for handwritten similar Chinese characters based on wavelet transform and elastic meshing technique, partial space method and support vector machines (SVM) theory. The technique of combining wavelet transform with elastic meshing is employed for a given handwritten character to extract its feature. In addition, partial space method is adopted to select some components of the feature vector showing the main difference among similar Chinese characters. Finally, SVM classifier based on the Gaussian kernel function is exploited to obtain the recognition result. The experiment results confirm the effectiveness and practicality of the approach.
Novel valve control method of simulating human intelligence and its application to oil delivery control system
Yaqing Tu, Youpin Lian, Du Zhang
In this paper, we propose a valve intelligent control method and discuss its application to an oil delivery control system. The proposed method is based on a staged rule control of a valve to turn-up/turn-down operations during the oil filling process. A set of rules coming from simulating human intelligence is defined for the contact points of a valve so that its behavior is precisely specified. The main advantage of the approach is its improved control method error of oil filling in pipeline. Experiments have been performed and the comparative results indicate that our proposed method indeed yield better system precision than that of the conventional valve control method.
Optimal feedback missile guidance law using neural networks
Rui Zhou
It is general impossible to obtain the analytic optimal guidance law for the complex nonlinear guidance systems of the homing missiles, and the open loop optimal guidance law is often obtained by numerical methods, which can not be used directly in practice. The neural networks are trained off-line using the optimal trajectory of missile produced by the numerical open loop optimal guidance law, and then, the converged neural networks are used on-line as the feedback optimal guidance law in real-time. The research shows that the different selections of the neural networks inputs, such as the system state variables or the rate of LOS (line of sight), may have great effect on the performances of the guidance systems for homing missiles. The robustness for several guidance laws are investigated by simulations. Some useful conclusions are obtained by simulation results.
Computer-controlled and robotized micromanipulation system for bioengineering
Yida Hu, Shusheng Bi, Guanghua Zong, et al.
A computer-controlled and robotized bio-micromanipulation system was developed. Robotic technology was made use of to build the system with high accuracy and autonomous ability, in line with the consideration that the biological micromanipulation processes its own characteristics. As control strategies at respective level in control scheme, visual servo and online real-time path planning are also the effective means to realize automation of micromanipulation. A dynamic look-and-move approach based on image feature was applied to visual servo in the light of the specific system structure. A Sub-goal Guiding method suited to the operation conditions of cell micromanipulation was proposed to execute online real-time path planning. Experiment results have showed the effectivity of the methods and the practicability of the micromanipulation system.
Smart networked transducer interface plug-and-play design and its application in robotic sensing system
Zhongcheng Wu, Min Qian, Fei Shen
A smart transducer network consisting of a set of transducer nodes with CANBUS was introduced in this paper for robot sensing system real-time measurement and control. The design idea was based on IEEE1451 transducer interface standards, which utilize existing control networking technology and develop standardized connection methods for smart transducers to control networks. Some requirements, such as 'plug-and-play' capability, system integration and dynamic reconfiguration, were described, which is achieved through a 'transducer electronic data sheet' (TEDS) in our networked transducer module.
Availability analysis based on performance for LAN
Shaoping Wang, Daoyu Tang
This paper presents an availability analysis method based on performance indices for Local Area Network (LAN). Through decomposing the complex LAN into several independent sub nets, this paper establishes the modular availability model with GSPN (Generalized Stochastic Petri Net), which considers the interaction among software, hardware and protocol. From the angle of user interest, the interactions between modular sub nets are linked with service performance of LAN such as throughput and transition delay. Directing to the difference between rapid net and slow net in ALN, this paper presents the time-order algorithms to calculate their availability respectively. Connect the reliability of various nets at system level and optimize the object function of synthetic availability to realize the availability analysis for LAN. The experimental results indicate that the availability model and its time-order algorithm are content.
Nonlinear filtering method for emissivity correction of PCB infrared thermal images
Jiuqing Wan, Xingshan Li
In the diagnosis of Printed Circuit Board (PCB) based on infrared radiation, emissivity correction must be performed on the thermal image to retrieve the true temperature distribution on the PCB surface. Taking the measured PCB surface temperature as a combination of its true temperature distribution and its emissivity distribution, a non-linear filtering method was proposed to separate the true temperature from this combination based on the differences in the continuity of these two contributions. As the key step of the proposed method, the discontinuity detection is implemented through wavelet transform. Experimental results indicated that the true temperature distribution can be estimated precisely by the proposed method.
Realization of a remote equipment fault diagnosis and maintenance system based on intelligent computation
Haifeng Yang, Hongbo Zhang, Jintao Hai
In order to supply more sufficient information support for equipment diagnosis at the same time of signal process, an intelligent computation technique, the Autonomous Oriented Computation Network (AOCN), was proposed. This paper discussed the principles, the building process, the computation and its application of AOCN, and presented the frame of remote intelligent diagnosis and virtual maintenance system of wear of friction bearing based on the Browser/Server structure. By combining the Bayesian regularized BP network simulation and the visualization of virtual reality, the remote intelligent diagnosis of wear status of sliding bearing was carried out. According to the diagnosis result, a virtual visualization fault maintenance proposal concerning equipment was presented for users. Through experiment, the net computation result of this system was confirmed.
Error analysis in frequency domain for fiber optic gyro attitude reference and control system
Wenqi Wu, Libin Zhu, Mingming Jiang, et al.
A shipboard attitude reference and control system using fiber optic gyros is analyzed. In this system, the frequency character of the attitude error is more concerned, because high frequency attitude measuring errors can some times cause vibration in control system. In this paper, system kinematic model using quaternion is addressed and stabilization analysis based on Lyapunov theory is presented. By time-frequency distribution analysis, it is pointed out that the key problem is how to confine the high frequency body attitude errors and angular velocity errors measured by the fiber optic gyros. Lowpass filter is imposed to solve this problem. In this way, while the high frequency attitude vibrations are restrained, the body attitude error would become larger. Frequency domain confinement and time domain confinement to the system errors should be balanced in practical engineering.
Fault diagnosis for stator winding bar hollow strand blockage of turbogenerators based on data fusion
Xianpei Wang, Zheng Y. Dai, Zhenxing Liu, et al.
Stator Winding Bar Hollow Strand Blockage (SWBHSB) is one of the main faults for large turbo-generators with water and hydrogen cooling system. It will lead to increasing water temperature at the bar exit which may cause hidden troubles for turbo-generator's security. According to a three-layer-structural model of data fusion, this paper presents a fault diagnosis method for turbo-generators based on data fusion technology. Firstly, a bp network on pixel level fusion is set up, in which several temperature parameters at the bar exit are accurately computed. Then in feature level fusion, the fingerprints are distilled from the result of pixel level fusion. Finally, decision level fusion gives a fault diagnosis for the measuring channels and thermometric components. This method can effectively avoid problems such as misinformation and fake report.
Performance analysis of hierarchical fusion approaches for CCD/IR images
Yanli Wang, Zhe Chen
Hierarchical image fusion approaches for CCD/IR images are studied and the performance analysis of these fusion approaches is completed in this paper. The Hierarchical fusion methods include FSD pyramid, Laplacian pyramid, ration pyramid, contrast pyramid, gradient pyramid, morphological pyramid and discrete wavelet transform. The performance measures of evaluating fusion images deal with standard deviation, entropy, cross entropy and spatial frequency. Experimental results show that morphology pyramid method is more suitable for CCD/IR image fusion than other ones proposed in this paper.
Analysis of the reliabilities of maglev train power system with FTA method
Zhiqiang Long, Zhiquo Lu, Huixing Chen, et al.
As to the high safeties and reliabilities of the magnetic suspension train, the most fundamental rule is that under all supposed running disturbances, faults, and other urgent conditions, and at any time, the running train can all stop at any given point, where the passengers can get off the train completely and can all find a safe stopping place. The object studied in this paper is the CMS-3 type electromagnetic suspension sample train developed in the National University of Defense Technology. Based on the method of fault tree analysis, the safeties and the reliabilities of the key part (the power system) of the train are analyzed systematically. And the instructive viewpoints and the improving measures are put forward.
Design of intelligent diagnosis system based on CBR for jet engine
Bo Xu, Xingshan Li, Jinsong Yu
Condition monitoring and fault diagnosis are crucial for insuring flight safety. According to characteristics of complex systems, this paper proposes an intelligent system for off-line fault detection and diagnosis for gas path components in jet engine. Based on a machine learning methodology named Case-based Reasoning (CBR), this system consists of two types of case-bases, static case-base and dynamic case-base. Dynamic time warping (DTW) is used to retrieve dynamic cases by assessing the similarity between two dynamic sequence samples.
Intelligent liquid surface measuring system based on laser ranging
Song Li, Ping'an He, Jianzhong Han, et al.
Using laser range finder DISTO as a sensor, we developed an intelligent liquid surface measuring system that can be used to measure the depth of liquid. Many problems such as liquid surface reflected in fixed direction, measuring errors caused by reflex reflections and liquid surface fluctuation are solved. Now it is proved by our experiments on the spot that the system would be used in measuring depth of all kind of liquid, especially in combustible or explosive oil and liquefaction gas with the accuracy of +/-3mm.