Nanomeasuring and nanopositioning engineering
Author(s):
G. Jäger;
T. Hausotte;
E. Manske;
H.-J. Büchner;
R. Mastylo;
N. Dorozhovets;
N. Hofmann
Show Abstract
The paper describes traceable nanometrology based on a nanopositioning machine with integrated nanoprobes. The operation of a high-precision long range three-dimensional nanopositioning and nanomeasuring machine (NPM-Machine) having a resolution of 0,1 nm over the positioning and measuring range of 25 mm x 25 mm x 5 mm is explained. An Abbe offset-free design of three miniature plan mirror interferometers and applying a new concept for compensating systematic errors resulting from mechanical guide systems provide very small uncertainties of measurement. The NPM-Machine has been developed by the Institute of Process Measurement and Sensor Technology of the Technische Universitaet Ilmenau and manufactured by the SIOS Messtechnik GmbH Ilmenau. The machines are operating successfully in several German and foreign research institutes including the Physikalisch-Technische Bundesanstalt (PTB), Germany. The integration of several, optical and tactile probe systems and nanotools makes the NPM-Machine suitable for various tasks, such as large-area scanning probe microscopy, mask and wafer inspection, nanostructuring, biotechnology and genetic engineering as well as measuring mechanical precision workpieces, precision treatment and for engineering new material. Various developed probe systems have been integrated into the NPM-Machine. The measurement results of a focus sensor, metrological AFM, white light sensor, tactile stylus probe and of a 3D-micro-touch-probe are presented. Single beam-, double beam- and triple beam interferometers built in the NPM-Machine for six degrees of freedom measurements are described.
Mechanical machining and metrology at micro/nano scale
Author(s):
Steven Y. Liang
Show Abstract
Micro-scale machining performed in a mechanical manner is an ultra-precision material removal process to achieve micron form accuracy and a few nanometer finish. It has gained increasing importance in the manufacture of optical, mechanical, biomedical, and electronic components with intricate details in many industry and consumer products, both as a means to produce final products and to create dies and molds for further mass production. The backbone of science and technology for the success of machining at such fine length scales hinges on the understanding of microstructual machining mechanics, precision control of machine tool motions, miniaturization of cutters, miniaturization of machine tools, and the availability of high resolution metrology. This paper examines a number of recent research developments at Georgia Tech in these areas. On microstructual mechanics, cutting at submicron depth to control brittle-ductile transition of material will be discussed. On precision machine control, compensation of micrometer multitooth runout error through the chip load servo will be illustrated. On cutter miniaturization, the concept of magnetic single-grit abrasive as a micro cutting tool for submicron dimensional accuracy will be presented. On machine tool miniaturization, the downsizing of machining center and its associated benefits on precision will be elaborated. On metrology, a micro laser-based system and acoustic emission systems are presented for the measurement of micro cutting tool locations. The presentation of these topics will focus on the underlying fundamentals of fine scale machining and their implications toward ultra-precision engineering and micro/nano manufacturing.
Novel optical measuring systems and laser technologies for science and industry
Author(s):
Yuri Chugui;
Sergei Plotnikov;
Anatoly Potashnikov;
Alexander Verkhogliad
Show Abstract
The novel results of the R & D activity of TDI SIE SB RAS in the field of the optical measuring technologies, as well as laser technologies for solving safety problems are presented. To measure the rocks stress and to prevent the mountain impact, as well as for basic investigations, a set of optical-electronic deformers and systems was developed and produced. For permanent noncontact bearing position inspection of oil-drilling platforms on Sakhalin coast (Russia) we have developed optical-electronic method and system SAKHALIN with cumulative traveled distance (3 km) measurement error less than 0.03 %. Multifunctional laser technological system LSP-2000 equipped by two Nd-YAG lasers was developed for cutting, welding and surface micro profiling with ablation process (working range of 3 × 2 × 0.6 m3, positioning error less than 10 mkm). Safety of Russian nuclear reactors takes 100 % noncontact 3D dimensional inspection of all parts of fuel assemblies, including grid spacers. Results of development and testing the specialized high productive laser measuring machine, based on structured illumination, for 3D inspection of grid spacers with micron resolution are presented. Ensuring the safety of running trains is the actual task for railways. Using high-speed laser noncontact method on the base of triangulation position sensors, TDI SIE has developed and produced automatic laser diagnostic system COMPLEX for inspection of geometric parameters of wheel pairs (train speed up to 60 km/hr.), which is used successfully on Russian railways. Experimental results on measuring and laser technological systems testing are presented.
Low power grating detection system chip for high-speed low cost length and angle precision measurement
Author(s):
Ligang Hou;
Rengui Luo;
Wuchen Wu
Show Abstract
This paper forwards a low power grating detection chip (EYAS) on length and angle precision measurement. Traditional grating detection method, such as resister chain divide or phase locked divide circuit are difficult to design and tune. The need of an additional CPU for control and display makes these methods' implementation more complex and costly. Traditional methods also suffer low sampling speed for the complex divide circuit scheme and CPU software compensation. EYAS is an application specific integrated circuit (ASIC). It integrates micro controller unit (MCU), power management unit (PMU), LCD controller, Keyboard interface, grating detection unit and other peripherals. Working at 10MHz, EYAS can afford 5MHz internal sampling rate and can handle 1.25MHz orthogonal signal from grating sensor. With a simple control interface by keyboard, sensor parameter, data processing and system working mode can be configured. Two LCD controllers can adapt to dot array LCD or segment bit LCD, which comprised output interface. PMU alters system between working and standby mode by clock gating technique to save power. EYAS in test mode (system action are more frequently than real world use) consumes 0.9mw, while 0.2mw in real world use. EYAS achieved the whole grating detection system function, high-speed orthogonal signal handling in a single chip with very low power consumption.
Development of a new angular displacement sensor based on principle of vernier caliper
Author(s):
Xinghong Zhang;
Donglin Peng;
Xihou Chen;
Xiaokang Liu
Show Abstract
In this paper, a new kind of angular high precision displacement based on principle of vernier caliper is proposed. This displacement is sourced from the idea of vernier caliper. The longer arm of vernier caliper with a linear scale and the L-shaped sliding attachment with a vernier are replaced by an inner round part and outer round part with reticle around them. The numbers of reticle around inner part is different from that of outer part. Using the reticle number difference between two parts having relative motion, in the condition of the similar reticle, there exist changes of some physical parameter among the reticles. It can gain more pulse signal. In some cases, the numbers of pulse signal is approximately equal to the product of the two numbers of reticles around inner and outer round parts, which has identical consequence of pulse interpolation or frequency doubling. Through which the goal of improving resolution is achieved. The design idea, the working principle, the signal analysis, the precision analysis and the experiment result of this angular displacement sensor are introduced. The research result shows that thickness, spacing and number of reticles can directly affect the number, amplitude, wave shape, accuracy and other characteristics of the pulse signal. It will play an important rule in improving the traditional grating type angular displacement sensor technology.
Nonlinearity error separation and self-correction methods for time grating displacement sensor
Author(s):
Xiaokang Liu;
Donglin Peng;
Xianquan Wang;
Wei Yang
Show Abstract
A novel type of displacement sensor named time grating is introduced for measuring space with time. Multi-position probes measuring method is used to separate the non-linearity error of time grating, and Fourier series harmonic wave correction method is proposed to correct the error by software. Experiment results coming out from applications conform the remarkable effectiveness of these methods. A time grating displacement sensor with accuracy of ±0.8" is developed. Test results show that high-precision measurement is achieved without high-precision manufacture. The realization of error self-correction endows time grating sensor with intelligence.
Research on pitch analysis methods for calibration of one-dimensional grating standard based on nanometrological AFM
Author(s):
Qiangxian Huang;
Satoshi Gonda;
Ichiko Misumi;
Taeho Keem;
Tomizo Kurosawa
Show Abstract
By present, the calibration of dimensions in nano scale is being paid more and more attentions. One-dimensional
grating standard with pitches in nano-scale is being proposed by the CCL-WGDM 7 to be one of the five key
comparison parameters in the emerging field of nanometrology. In the pitch calibration of grating standard, Gravity
Center Method and Zero-Cross Points Method are proposed. The two methods are analyzed and simulated under
different conditions. Based on the actual measurement data obtained by AFM, the two methods are used and the best
value is determined. The results in the paper are useful to pitch calibration in nano scale.
A linear diffraction grating interferometer with high accuracy
Author(s):
Kuang-Chao Fan;
Yu-Sheng Liu;
Ye-Jin Chen;
Fang Cheng
Show Abstract
A new miniature nanometer interferometer using grating Doppler effect is developed. The principle of this interferometer can be attributed to the phase information encoded by the ±1st order diffractive light beams. Properly interfering these two light beams leads to modulation similar to Doppler frequency shift, which can be translated to displacement measurement via phase decoding. Because of the measurement standard of grating interferometer system is the grating pitch, compared to the commonly used laser interferometer, the diffractive grating system reduces the environment influences on measurement accuracy. The calibration experiment between grating and HP5529A has been implemented. The measurement results show this grating interferometer measurement system is applicable for higher accuracy in long stroke.
Research of eliminating temperature interference in stress measurement by fiber Bragg grating
Author(s):
Yutian Wang;
Lifang Cao;
Qinghua Wang;
Xuecai Liu
Show Abstract
In this paper, a set of experimental equipment is outlined which is designed to eliminate temperature change influence in stress measurement. A Fiber Bragg Grating (FBG) is fixed to a specially-structured cantilever, then the load brought to beat at the free end of cantilever. As the load exerted to the cantilever is changed, the stress of FBG changes. From the experiment, we can see that at the beginning of distortion caused by the load, the center wavelength of fiber grating changes, but the chirp effect is not obvious. As the load increases, the spectrum of reflecting peak becomes wider, and
the chirp effect becomes more obvious, then two reflecting peaks appear, and the distance of two center wavelengths increases as linearity. When weights are added to 200g, two center wavelengths are 1548.25nm and 1548.43nm and the distance of them is 0.18nm. Experimental results indicate that the distance of two reflect peaks changes in linear relationship with the increasing of load on the free end of the cantilever, and the linearity is up to 0.96. Using this way to package FBG, the cross-sensitivity of stress and temperature can be conquered, and the error caused by temperature change in stress measurement can be eliminated. Therefore, the stress measurement can be realized by one fiber grating.
Analysis of fluctuation equation in time-grating and new method for generating traveling wave
Author(s):
Wei Yang;
Donglin Peng;
Xinghong Zhang;
Xiaokang Liu
Show Abstract
In this paper, the principle to generate the moving coordinate in time grating displacement sensor is analyzed. In order to simplify the structure of the time grating sensor and make its manufacture more easily, its fluctuation equation is analyzed and the relation and distinction between electric traveling wave and magnetic traveling wave are discussed. Then a new method to generate traveling wave is proposed based on these discussions. The method is employed with its corresponding mechanical structure to form a new type time grating sensor. Experimental results show that the sensor can generate correct signal and the method is feasible. Thus the traditional electrical machinery method can be replaced by a new method to generate the moving magnetic field. This new method can simplify the manufacture process greatly.
Study on the precise time-grating displacement sensor
Author(s):
Wei Yang;
Donglin Peng;
Xiaokang Liu;
Xinghong Zhang
Show Abstract
This paper analyzes the mechanism of the traditional grating structure sensor and lists some disadvantages such as low resolution and weak anti-interfere. Aiming at these disadvantages, one innovative thought of "measuring space by time" is proposed. In this thought the displacement can be expressed by the time, and the time can be obtained by the method of high frequency pulse interpolation. The time measurement is very precise, so the displacement measurement would has high precision. The single tooth time grating displacement sensor is designed based on the thought. The single tooth time grating initially realizes the thought, but the effectiveness is not very ideal. Another design project, which is based on the rotary magnetic field in the motor, is presented. The sample for field type time grating has been designed. The experimental results coming out from applications confirm the validity of the proposed method.
Design of time grating displacement sensor based on transformer theory with varying coupling coefficient
Author(s):
Xihou Chen;
Donglin Peng;
Xinghong Zhang;
Wei Yang
Show Abstract
Time grating displacement sensor realizes high precision measuring by counting some certain time pulses. Generating a travelling wave, which is related to the measured displacement, is a key tache in measuring process of time grating. Three-phase winding is used to generate travelling wave in field type time grating sensor, but uneven distribution of the winding may arouse measurement error. Tooth-grating structure is adopted to generate travelling wave in differential grating type time grating sensor, but the precision of this type sensor is very sensitive to machining precision of teeth. A new method to generate travelling wave is firstly proposed in this paper. This method is based on transformer theory with varying coupling coefficient. Employing a two pairs of face gears and two transformers structure, the sensor converts the change of rotator's displacement into the varieties of two transformers' coupling coefficient. Then coupling coefficient varieties cause the changes of signals' amplitude in both transformers' secondary coils. When the signals feeding to the two primary coils are two sine waves which have a 90° difference in phase and the positions of two pairs of face gears have a half tooth difference in space, the two signals induced by secondary windings can be added up and generate a travlling wave which is related to the displacement of rotator. According to this principle a novel type of time grating sensor is developed. Experiment results show that the correct signal can be generated and the new time grating sensor can get higher original precision.
The application of the pretreatment and cycle stream of control to measurement and control by computer
Author(s):
Ge Zhu;
Min Wu;
Donglin Peng
Show Abstract
A new method "Pretreatment and cycle stream of control" is raised in this paper. It has synthesized the characteristic of
software and hardware, and has succeeded in the problem of real time in process of measurment and control by computer
had been solved. this core idea of the project research is: the hardware electric circuit cycle in the space region which is
distributed to form chain and cycle ( in a nested way ) + the software sentence cycle in the time region which is
distinguished by scales == the real time controlled cycle controlled cycle of Pretreated control stream.
Detecting devices in dynamic, module, and time sharing
Author(s):
Xiaogang Lin;
Yingjun Pan;
Chao Gao;
Yongcai Guo
Show Abstract
In the research and development of multi-parameter precision detecting system, various parameters need to be measured (such as length, diameter, surface roughness and so on). We not only measure some parameters statically but also measure others dynamically and calculate others (such as volume, density) using some detected parameters. At the same time, this system need higher precision and higher measuring speed. We propose a new detecting idea for this system--detecting devices in dynamic, module and time-sharing. And we design and optimize multi-parameter high precision measurement system employing the method. This idea includes three parts: the first part is dynamical part. We can make system more stability and more continuity in high detecting speed. The second part is module part. We can settle on a solution to measure similar parameters and make system structure more reasonable and reduce error factors. The third is time-sharing part. We solve the problem how to allot time to every parameter and make every measurement part and its software tie in. The detecting idea has been employed to design and optimize several multi-parameter precision detecting systems. Now these systems are running successfully in workshop.
Basic principle of a new measurement system of long measuring range of digital modulation
Author(s):
Zeng-yao Zhang;
Qian-min Mao
Show Abstract
Usually a capacitive displacement transducer (CDT) is made by printed-circuit-board (PCB) technology, so the reduced pitches of electrodes are limited by PCB technology and lead wire design, and the increase of its resolution, too. If a line array source replaces the transmitting electrodes of the CDT, a scale grating replaces the scale electrodes and a detector replaces the pick-up electrode of the CDT and also increase its number of the subdivision, the solution could be greatly improved on condition that the mathematical model of the CDT is maintained. Grating technology is organically combined with CDT technology. The basic operation principle of the system is as follows: a linear array source has several groups and every group has 8 light cell (organic light-emitting diode (OLED), or Liquid Crystal on Silicon Display (LCoS). (these line array sources are required to determinate speed response). The pitch of the cells is w. Every cell emits a light signal if driven by a digital signal. The pitch of the scale grating is W (=8w). The transmission (or reflection) characteristic function of the scale grating is Ti(x). After Ii(t) passes through the scale grating and is modulated by the displacement x of the scale grating, the total intensity I(x,t) is obtained. The photoelectric detector receives I(x,t) and transforms it into an electric signal. Subsequently the signal is demodulated and filtered, thus the fundamental harmonic of I1(x,t) is obtained. It is obvious, that the phase of I1(x,t) has a linear relation with x. After processing the phase demodulation circuit and the MPU, the displacement x of the scale grating is obtained.
Research on fusion measurement technology of capacitive displacement transducer and grating
Author(s):
Qian-min Mao;
Zeng-yao Zhang;
Yong-jun Zheng
Show Abstract
The design techniques of actuating signal source in capacitive displacement transducer measurement system is used for designing a group of multiphase modulation signal source, which generates the multiphase linear light source actuating signal for grating measurement system, after the emitted multiphase modulating light signal is modulated by a scale grating, it is received by a photoelectric component and a compound electrical signal is obtained. Another electrical signal is obtained after processed by circuit, whose frequency is same as the fundamental frequency of actuating signal source, the movement distance x of scale grating can be obtained by detecting the change of phase difference between two electrical signals. Sub-micron or nanometer-level measurement resolution is reached by organically integrating the capacitive displacement transducer and grating measurement technology, by increasing the subdivision number of phase detecting circuit, and by decreasing the point distance of linear light source.
Design of frequency divider based on FPGA
Author(s):
Yi Hu;
Xia Wang;
Yetai Fei
Show Abstract
This paper introduces the realization of half-integral frequency divider on the principle and gives the circuit schematic
diagram. Based on the half-integral frequency divider, a design method of a general frequency divider is given by
controlling the gating of exclusive-OR gate. Even, odd and decimal frequency division is realized using the model of the
general frequency divider, which is designed by use of VHDL hardware description language and the schematic diagram
input mode with the development software of MAX+plus II. The low layer VHDL descriptions and the designs of top
layer schematic diagram of the frequency divider are presented in the paper. To validate the design, the designed dividers
which have different coefficient of frequency division are simulated, and the figures are presented. Results of experiment
in the device of ALTERA Corporation's EPF10K20 proof much more that the general frequency divider can realize a
several of frequency division functions.
A high-resolution displacement sensor based on multiple feedback effect of birefringence dual frequency lasers
Author(s):
Wei Mao;
Shulian Zhang
Show Abstract
A high-resolution displacement sensor based on multiple feedback effect of birefringence dual frequency lasers has been presented and demonstrated. When the system operates in very strong feedback regime with asymmetric feedback induced by incline of an external feedback reflector in an orthogonal polarized dual frequency laser, the modulation frequency of the laser intensity is seven times higher than what the conventional optical feedback system can achieve, due to multiple feedback effect. A fringe shift will correspond to a displacement of a fourteenth wavelength of the external reflector. The intensity transferring periodically between the two frequencies is studied. One period of intensity transfer can be divided into four states: o-light, o-light and e-light, e-light, and no light, and each polarization state corresponds to λ/56 displacement of the external reflector. According to the appearing sequence of the four states, the movement direction of external reflector can be discriminated. Thus, a novel displacement sensor with a resolution of being as high as 11.3 nm, as well as function of direction discrimination, is believed to achieve.
Heterodyne interferometer for measurement of in-plane displacement with subnanometer resolution
Author(s):
Ju-Yi Lee;
Hui-Yi Chen;
Cheng-Chih Hsu;
Chyan-Chyi Wu
Show Abstract
A novel method of the measurement of in-plane displacement is presented. This method includes a heterodyne light source, a moving grating and a lock-in amplifier for phase measurement. The phase variation which resulted from the grating movement is measured by an optical heterodyne interferometer. The short and long displacement can be measured by our method. The theoretical resolution is about 1 pm. If considering the high frequency noise, the measurement error or resolution is about 0.2 nm yet.
A laser structured light system for inspection of wear and defects of contact wire in train's electro-supply network
Author(s):
Vladimir Bazin;
Yuri Chugui;
Stepan Kalichkin;
Sergei Makarov;
Alexander Verkhogliad;
Ignat Vykhristyuk
Show Abstract
An optical structured illumination of 3D object as a light band method of wear measurement and defects detection of a contact wire network on railways, tram, trolleybus lines and similar systems of vehicles electro-supply is presented. The experimental device can extract main technological wire parameters, as its remaining height with rms value down to 0.1 mm. Also the cross-sectional area of the wire can be measured with rms area noise value of 1.5mm2, which is sufficient for confident decision-making related to the automatic wire wears and defects.
High precision large scale metrology using a chirped laser pulse
Author(s):
Zhongyu Wang;
Jihua Fu;
Hao Meng
Show Abstract
A new method of laser range finder for precise large scale metrology is proposed. A chirped laser pulse with femtosecond durations is selected to work as the laser resource for the pulsed lidar to obtain the distance information. The chirped pulse's time domain and frequency domain specification are fully used in the double modulation, which combines the time-of-flight methods' advantages in distance measurement, such as high resolution, large measuring range and without measuring reference. An opportunity of absolute large scale metrology with the high accuracy is shown.
Laser range finding using DSSS and PSK modulation
Author(s):
Xuedong Jia;
Lixing Jiang;
Fengke Jie;
Anjian Wang
Show Abstract
A new laser range finding method using direct sequence spreads spectrum (DSSS) and phase-shift keying (PSK) modulation is described in this paper. Comparing with pulse, phase-shift and other normal methods, it provides more benefits such as improving receiver sensitivity and avoiding range ambiguity, due to the property of long periodic pseudo noise (PN) sequence. The operation theory and simulation result are also introduced.
Design and simulation of a mixer and phase difference measuring circuitry for laser range finding systems
Author(s):
Guili Liu;
Yanlin Wang;
Gang Liu
Show Abstract
This article focuses on the circuit implementation of a mixer and phase difference measurement for laser range finding systems. It will introduce simply the principle of the laser range finding system, which is the basis of the electronic circuitry design. The modulated laser lights of two different frequencies are mixed and the phase difference is detected in order to measure the range. The method of measuring the range is to use the mixer and the phase difference detector. The new and high precision IC that has a high quality makes the circuit simple and reliable. The circuit of the mixer and the phase difference detector for laser range finding systems is designed using AD608 and AD8302 chips.
Deep submicro flying height measuring technologies system
Author(s):
Yuhe Li;
Liang Wang;
Qingxiang Li
Show Abstract
This paper describes a technique for the measurement of deep sub-micron flying height based on intensity interferometry, focuses on the introduction of operating principles, system configuration and image visual feedback techniques. Because the flying height is super low, micro pitch or roll of the slider will lead to measuring error. Thus a constant relative position between the optic spot and the slider should be assured. Imaging processing technique is used to obtain the coordinates of both the slider and the optic spot. A detection algorithm of the center of circle is detailed in this paper.
Study of coordinate measuring machines synthetic dynamic error under different positions and speeds based on dual linear returns
Author(s):
Xiushui Ma;
Yetai Fei;
Hongtao Wang;
Zhongyang Ying;
Guang Li
Show Abstract
Modern manufacturing increasingly places a high requirement on the speed and accuracy of Coordinate Measuring Machines (CMMs). Measuring speed has become one of the key factors in evaluating the performance of CMMs. In high speed measuring, dynamic error will have a greater influence on accuracy. This paper tests the dynamic error of CMM's measuring system under different measuring positions and speeds using the dual frequency laser interferometer. Based on measured data, the modeling of synthetic dynamic errors is set up adopting the dual linear returns method. Comparing with the measured data, the relative error of modeling is between 15% to 20%, the returns equation is prominent at α=0.01 level, verified by "F". Based on the modeling of synthetic dynamic errors under different measuring positions and speeds, the measuring system dynamic error of CMMs is corrected and reduced.
A high-sensitivity optical touch trigger probe for down scaled 3D CMMs
Author(s):
Hong Ji;
L. X. Kong;
H. Y. Hsu;
A. B. Wedding;
G. C. I. Lin;
K. C. Fan
Show Abstract
With the reduction in dimensions of products in the last decade, the need for highly accurate dimensional inspection and measurement increases, which requires down scaled measuring tools. The key element for a powerful down scaled dimensional measuring tool coordinate measuring machine is the downscaled probe. In order to satisfy the ongoing increasing demand for highly accurate geometrical measurements on small parts and small structures, a new measuring probe having high sensitivity and small geometrical dimension with low contact forces needs to be developed. In this paper, a novel probing system, which combines a FBG (Fibre Bragg Grating) embedded optical fibre tactile probe with an optical sensing technique, is proposed for down scaled 3D micro-CMMs. The Bragg wavelength shifts with the strain developed along the fibre once the fibre touches the surface of the part. With high-resolution interferometric wavelength demodulation technology, a resolution of 5nm could be achieved by the FBG integrated system. With the sensor elements integrated into the probe tip directly, the system sensitivity can be increased significantly for 3 dimensional measurements.
A contact CMM probe based on parallel optical detecting
Author(s):
Yonghong Wang;
Xiaofen Yu
Show Abstract
Based on parallel optical detecting principle, a contact CMM probe is proposed. A 2D light source array produced by the micro-optic component is used to form parallel micro-astigmatism system. When the probe comes into contact with workpiece, the reflecting point of each astigmatism path was deflected. The deflect information can be got through the change of the light intensity and the probe position can be obtained finally. It combines the advantages of optical non-contact method and mechanical contact one. The probe could provide trigger signal and zero cross detection, it also could obtain XYZ micrometer signal. Compared with the traditional electric trigger probe, the probe is simple in the mechanism with high precision, and it is easy to realize the micromation and integration. The construction and working principle of the contact CMM probe are investigated. Furthermore, experiment result is obtained, which accords with theory analysis. It indicates that parallel optical detecting method is applicable in contact CMM probe.
A method for the calibration of step gauges
Author(s):
Hao Yan;
Wuyi Wang
Show Abstract
To calibrate step gauges, a new linear measuring system was improved in our laboratory that combines the Leitz universal measuring machine of the 1960s with a laser interferometer. This paper introduces the measurement method and the calculation of the expanded uncertainty of the measurement. The expanded uncertainty of the system is (0.3 + L) μm at k=2, where L is given in meter.
Research of measuring accuracy of laser tracker system
Author(s):
Jianfei Ouyang;
Zhiyong Liang;
Haixin Zhang;
Yonggang Yan
Show Abstract
This paper presents the achievement of a China NSFC project. The Laser Tracker System (LTS) is a portable 3D large size measuring system. The measuring conditions such as time and temperature can greatly affect the measuring accuracy of LTS. This paper pays a great attention to study how the time and temperature affect the measuring accuracy of LTS. Coordinate Measuring Machine (CMM) is employed as a high-level measuring instrument to validate LTS. The experiments have been done to find how the time and temperature affect the measuring accuracy of LTS. The experiments show the LTS can work well with the highest measuring accuracy just after three-hour warm-up. However, the LTS becomes unstable and the measuring accuracy decreases after 10 hours. The LTS needs calibration and compensation every 10 hours. The experiments show that the measuring error can be up to 29.6μm when the measuring temperature is 30.5°C even if the measuring error is less than 5.9μm while the temperature is between 20°C and 23.8°C. The research provides a very useful guidance for application of LTS.
Accuracy distribution and determination of the flexible three-coordinate measuring machine
Author(s):
Chunhua Wang;
Yetai Fei;
Penghao Hu;
Pingping Wang;
Wentao Chen
Show Abstract
Accuracy Distribution and Determination is one key step in instrument design and it influences manufacturing cost and final accuracy of machine. So, the analysis about instrument accuracy needs to be paid more attention before manufacturing. Flexible CMM has attracted lots of eyes recent years in the world. This paper gives the analysis result of the flexible CMM. At first, a typical flexible CMM is briefly introduced and the system combines 6 angle encoders and 2 measuring arms and one probe. Secondly, the measuring mathematic model is derived and the error of the parameters of the system is analyzed base on the model. Thirdly, the accuracy of the key parameters of the system have been distributed and determined according to the analysis. Finally, the theory has been approved in a practical flexible CMM. So, the theory of accuracy distribution and determination is the basement of design and manufacturing and it plays a great role in the instrument design.
Surface roughness parameters measurements by digital holographic microscopy (DHM)
Author(s):
Frédéric Montfort;
Yves Emery;
Eduardo Solanas;
Etienne Cuche;
Nicolas Aspert;
Pierre Marquet;
Claude Joris;
Jonas Kühn;
Christian Depeursing
Show Abstract
Digital Holographic Microscopes (DHM) allows the capture of all the information necessary to provide 3D phase measurements with a nanometer vertical resolution in a single image acquisition. DHM images provide measurements of the surface topography which can be used for surface analysis, roughness measurements for example. In this paper we present roughness measurements on micro-balls of different sizes for which numerical procedures are applied for form factor and waviness removal. DHM thus permits quantitative measurements of the roughness on a 2 dimensional area allowing enlarged information compared to common profilometers. Mean roughness of 5 to 30 nm are measured and compared to values obtained by a profilometer.
White-light interferometric measurement of spherical and aspherical surfaces
Author(s):
Suping Chang;
Tiebang Xie
Show Abstract
White-light interferometric techniques and image processing techniques have been widely applied in measurement of surface profiles. A new method based on two technologies to achieve the optical non-contact shape measurement for spherical and aspherical surfaces is presented in this paper. This method utilizes the pixels of the image to locate the points of surface and obtains the surface height information by a vertical scanning white-light interferometric system. A set of a three-dimensional stage composed of a fine and coarse two-step vertical driver, and a two-dimensional horizontal driver is designed to enlarge the measurement area and the vertical scanning range. The measurement precision depends on the the performance of the interference microscope and the three-dimensional stage, so the influence of the interference microscope on the measurement result and the precision of the stage are analyzed. In the stage, a grating sensor is used to monitor the scanning process and the scanning information is fed to driving circuit to compensate for the errors. Additionally, experiments are carried out and correlative results are also shown.
White-light interferometric techniques in microstructure measurement
Author(s):
Kao-Hui Lin;
Ya-Hui Hu
Show Abstract
In the optical non-contact measure fields, the white light interferometry technique is well-known. The measure resolutions of vertical and horizontal direction are determined by motion mechanism and grabbed images, respectively. Therefore, to permit measurement resolution of white light interferometry in 3D profile is very important. In this paper, a white light interferometric measurement technique that combines vertical scanning and phase shifting is proposed. High resolution of the vertical scanning technique can grab the images of short pitch displacement. The relationship between interference fringe and changed frequency of these images are solved by the FFT. Then, the interference fringe's center is computed by band-pass filter and maximum power position. The phase shifting is based on five-frame algorithm to acquire fringe order through vertical scanning. In the experiment result, first was used the grating that had calibrated by commercial instrument Talysurf CCI 6000 to calibrate the experiment implement longitudinal resolution, second was measured the roughness calibration gauge of Model SS-NS94/ No. N20674 /Ra 3.0μm. The results show that the resolution is arrived 1nm, it was quite obvious improving the traditional mechanic.
Characteristics of capacitance-micro-displacement for model of complex interior surface of the 3D Taiji ball and its applications
Author(s):
Ruo-Gu Zhu;
Kun Jiang;
Zhao-Bo Qing;
Yue-Hui Liu;
Jun Yan
Show Abstract
Taiji image originated from ancient China. It is not only the Taoism emblem but also the ancient graphic presentation sign to everything origin. It either has a too far-reaching impact on traditional culture of China, or is influencing the development of current natural science. On the basis of analyzing the classical philosophic theory of two-dimensional (2-D) Taiji image, we developed it into the model of complex interior surface-three-dimensional (3-D) Taiji ball, and explored its possible applications. Combining modern mathematics and physics knowledge, we have studied on the physical meaning of 3-D Taiji ball, thus the plane change of original Taiji image is developed into space change which is more close to the real world. The change layers are obvious increased notably, and the amount of information included in this model increases correspondingly. We also realized a special paper 3-D Taiji ball whose surface is coved with metal foil by means of laser manufacture. A new experiment set-up for measuring micro displace has been designed and constituted thus the relation between capacitance and micro displacement for the 3-D Taiji ball has performed. Experimental and theoretical analyses are also finished. This models of 3-D Taiji ball for physical characteristics are the first time set up. Experimental data and fitting curves between capacitance and micro displacement for the special paper Taiji ball coved with metal foil are suggested. It is shown that the special Taiji ball has less leakage capacitance or more strengthen electric field than an ordinary half ball capacitance. Finally their potential applied values are explored.
Study for both field intensity of radiation interference and test distance within the same radiator
Author(s):
Hong He;
Shijiu Jin;
Dajian Zhang;
Hui Meng;
Xianwei Zhu;
Lu Tang
Show Abstract
This text gives a deep study for the relationship between field intensity of radiation interference and test distance within a same radiator. Through basic theory study of radiation features of both electric doublet and magnetic doublet, as well as analysis and comparison of practically measured data, problem of big difference between calculated results out of E (symbol) 1/r and practically measured data is solved. The conclusion is the field intensity out of a single field source would decrease at Power 1.5 ~ 11.84 as Distance r increases but not decrease at Power 1, and the decreasing power is relative to the polarization style of field intensity.
Automatic optical-electronic system for measurements of elements shifts and deformations in huge mechanical and engineering constructions
Author(s):
Yuri Chugui;
Vladimir Bazin;
Alexander Verkhogliad;
Stepan Kalichkin;
Vadim Kalikin;
Sergei Makarov;
Sergei Savkov
Show Abstract
As it is known the mining of oil and gas offshore is carried out using the drilling platforms, which are extremely massive and inert. In order to avoid excessive stresses on platform, which is highly inertial object, it consists of few large parts (normally base and legs). Four friction pendulum bearings are used for mechanical link between the base and legs. The bearings functionality is to provide the protection of the platform from all possible mechanical loadings on the legs that might affect the base with the drill and other sensitive equipment. Mechanical loadings include different seismic movements, ice shifts, mechanical loadings during the drilling, heat expansion stress, etc. Bearings are worn out after certain distance traveled and have to be replaced when the movement resource is over. The most important parameter, which allows estimation the bearing resource, is measuring the cumulative distance traveled by the bearing from the beginning of its service with the relative accuracy better then 0.01%, and absolute displacement at ±350 mm range with accuracy better then 1 mm. For this purpose the automatic optical-electronic system for measurements of bearings movements was developed. Its main aim is continuous noncontact measurement of the bearing location and calculation of the total distance traveled by the bearing for any defined time period. Measuring principle of the system is based on optical image processing. The passive part of the system (optical target) is fixed on one part of construction while active part - a field measurement sensor (FMS) is installed on another part of construction that moves relative to the first one. The FMS continuously captures and processes the image of optical target. On the FMS output, after processing, the relative displacement between FMS and Optical Target is obtained with high degree of accuracy. The system was certified as a measuring tool as well as for the use in explosive environments (for gas and oil industry). It is designed for continuous 24-hours operation during 30 years.
Development of automatic 3D profile measuring system
Author(s):
Hong-Tsu Young;
WeiYen Lin
Show Abstract
The objective of this research is to develop a non-contact measurement system for micro-scale 3D geometry. The core of the system is based on Shape-from-Focus method. Corresponding digital images were taken at different heights with predefined step interval. The images taken were enhanced by image processing techniques including discrete Gaussian filtering and histogram equalization. The degree of the focused image was quantified and, then the height of each pixel was determined with Gaussian Interpolation. 3D geometry model of the specimen can be reconstructed. The system developed was verified with a standard sphere of radius 225 μm. The result gave the average radius of 221.56 μm with the standard deviation 8.95 μm. Feasibility of the measuring system was confirmed with satisfactory precision level.
Online multidimensional measurement of complex workpieces based on stereo computer vision
Author(s):
Zhenying Xu;
Zhihao Tang;
Yun Wang;
Yetai Fei
Show Abstract
This paper presents a new way for online multi-dimensional measurement of complex workpieces, which is based on the stereo computer vision. We also advanced a new algorithm to obtain the disparity image for the image matching. In this algorithm we combine the pyramid image-matching strategy and the means of dynamic programming, and then apply the sub-pixel matching. Thus, the characteristic lines and circles of the measured workpiece are reconstructed in the image space. Using Hough transform, we obtain the information of the circles and the lines in the measurand. Then we get the sizes required. Compared with those obtained by CMM, the results have quite high accuracy.
Vision measurement method for complex cross section of an object
Author(s):
Wenyi Deng;
Naiguang Lu;
Xiaoping Lou
Show Abstract
2-D vision approach used to measure dimensions of complex cross-section of an object is presented in the paper. Considering the complexity of profile in cross section, some methods for edge detection and geometric elements recognition are studied. The means that can acquire a fine boundary image is adopted. A special approach for recognizing all geometric elements in image is presented. The recognition is processed by matching elements in image with corresponding elements in a standard graph. The standard graph is drawn according to the machine drawing. The measurement for total parameters is accomplished at the same time. The measure precision is ± 0.05mm.
A large range noncontact profilometer
Author(s):
Xudong Yang;
Tiebang Xie
Show Abstract
Focus detection method is one of the primary non-contact measurement methods of surface topography. However, the
measuring range of traditional focus detection method is limited because the volume motor is adopted in the focus servo
system. The traditional method has inevitable non-linear error and other measurement error caused by the volume motor.
This paper presents a new non-contact profilometer based on an improved Foucault focus detection method. The
non-contact profilometer is a closed loop control system, which changes the traditional moving volume motor scanning
system into the moving platform scanning system. Without adopting volume motor, the non-contact profilometer has
large measuring range, high resolution and more measurement parameters. When the surface of workpiece is measured,
the undulation of microcosmic surface topography leads to the focusing error signal continuously. According to the
focusing error signal, the computer controls the piezoelectric actuator and the Z direction motor to drive the platform to
move vertically, which ensures that the focus is always on the surface of workpiece and the focusing error signal is zero.
The diffraction grating displacement sensor measures the vertical displacement of the workpiece, then the displacement
signals is processed by the characterization software as the results of the measurement. The non-contact profilometer can
measure roughness, waviness, shape error of different curved surfaces precisely.
Camera calibration for reverse engineering
Author(s):
Ming Kong;
Shi-min Wang;
Yi Lu;
Zai Luo;
Qianjing Tang
Show Abstract
3D surface reconstruction plays an important role in reverse engineering, which can be implemented by machine vision techniques. In the techniques, the calibration of the intrinsic and extrinsic parameters of a camera is very crucial to ensure the 3D reconstruction accuracy. This paper will present a neural network method for the calibration. This method uses weight matrixes to calculate the transformation matrix of the 3D points in a world frame against their corresponding 2D image pixels, and then the intrinsic and extrinsic parameters can be readily extracted from the matrix. The experimental results have shown that the method can obtain a precise calibration result.
Measurement accuracy improvement on high-precision sheet convexity using a laser scanning system
Author(s):
Junfeng Zhou;
Jianping Tan
Show Abstract
A scanning method to measure the convexity of thin-gauge roll castings is brought forward. With a laser scanner that is based on the difference measurement theory of a pair of laser beams, the thickness distribution is measured and the convexity is computed. In this paper, the system's structure with an equipment of high-precision sheet convexity measurement with lasers is introduced. The key technologies to improve the measuring precision of the measurement system are studied, which includes error avoidance and error restraint. In sheet thickness measurement systems with lasers, the vibration of the C-frame, which is excited by the vibration of the working environment, could cause the change of precision of the sensor position in the system, and affect the system's measuring precision. In this paper, by use of finite element method and modal analysis, the structure optimization of the C-frame is introduced. By the simulation and optimization, the natural frequencies are increased. At the same time, the key modes which can arouse sympathetic vibration are avoided. By optimization, the structure of the C-frame can be adapted to industrial environments and guarantees the measuring precision of the equipment. By use of the wavelet multi-resolution analysis method, the convexity measuring signal is analyzed. Errors in the convexity measuring signal are decomposed into single components and each of the components is in a different frequency channel and indicates a different error signal. After a restraining algorithm is used, the wavelet restoration of valid components of the measured signal is carried out and an error restraint for the convexity measurement is realized. The experiment shows that the methods studied are effective.
Study of the development platform of smart piezoelectricity sensors
Author(s):
Longjiang Zheng;
Haiyu Hou;
Xuhui Tang;
Yutian Wang
Show Abstract
With the emergence of the IEEE1451 standard, the development of smart sensor becomes more important to the manufacture of sensor. IEEE1451 standard is a set of standards that were established to address smart sensor systems and to develop a comprehensive set of sensor and software protocols. This standard defines a table of parameters that are held in the EEPROM of the sensors, named Transducer Electronic Datasheet (TEDS). TEDS can store much information of the transducer such as manufacture ID, model number, serial number, version letter, user date and calibration date and so on. In this paper, IEPE accelerometer is adopted as the piezoelectricity sensors in which TEDS is embed. DS2431 1024 bits 1-Wire programmable read-only memorizer is taken as the memorizer of TEDS date. DS9097U 1-Wire COM serial adapter is adopted to connect the 1-Wire device and RS-232 of the PC to transfer date between them. At last, use LabVIEW application to read and write the date of TEDS on the computer. The basic information of sensors can be written into TEDS and also can be changed through LabVIEW application. The main purpose of the development platform is to accomplish the read and write of the TDES data based on the IEEE1451 standard by using LabVIEW application. Then the sensor can be made to be smart, and the main task of the development platform is to compile program to read and write the information of TEDS.
Measurement of a silicon-based nonsilicon MEMS micromirror
Author(s):
Yuan Luo;
Yi Zhang;
Xiaodong Xu
Show Abstract
Optical devices are playing important roles for all optical network(AON) and micro electro mechanical system (MEMS)
technology is a core technology for optical devices because of its compactness, high integration level and cheapness.
MEMS micromirror is a key structure for some kinds of MEMS devices such as optical switch, variable optical
attenuator (VOA) and so on. The characteristics of the MEMS optical micromirror will determine the performances of
the devices. In this paper, some important optical and mechanical parameters of the novel silicon-based non-silicon
MEMS micromirror are measured, especially the torsion angle which is tested by using digital image processing. The
testing data presents that the surface topography of the novel micromirror is smoother than that of poly-silicon
micromirror and the reflective characteristic is also well. After building a micromirror angle testing digital image
processing system, the rotating angle of the micromirror is measured and the result shows that the micromirror could be
rotated with an angle based on theoretical analysis.
Reconstruction of velocity distribution in gas-solid two-phase flow based on two-layer array fan-beam optical sensor
Author(s):
Yang Li;
Hong-Wei Yue;
Zui-hong He;
Xiao-ying Liang
Show Abstract
This paper presents a novel approach that adopts full-orientated two-layer fan-beam optical sensor to measure the particle velocity. The scanning light source emit a 50° lamellar fan-beam in turn through the gas-solid two phase flow, and the projection data resulting extinction effect of solid particles are detected at the same time. The profile optical projection data of measured flow field of the two layers can be obtained through being stimulated array light source and detecting light signal at multiple angles in space, and the vertical velocity field can be reconstructed during the course of measurement in terms of two-dimension cross-correlation and backprojection algorithm. In this paper, the design of the sensor including spatial arrangement of the structural parts and basic principle are introduced, the mathematical model utilized for measuring the particle velocity is presented and the experimental results are shown. It provides a new means to reconstruct rapidly velocity field of the gas-solid two-phase flow.
Study on a high precision piezoelectric resonators quartz crystal temperature sensor by means of three dimensional finite element method
Author(s):
Hong Ai;
Xin Li;
Bo You;
Haiying Wang;
Jun Xu
Show Abstract
A new type of piezoelectric resonance quartz crystal temperature sensors which exhibits a high precision and a good stability has been developed. A Y-cut (4.05°) quartz resonator operating on low-frequency thickness C-mode was chosen as the temperature sensor because of its availability and its good linear frequency versus temperature characteristic. In order to reduce the mounting effects and to decouple interfering modes of motion, the contour structures of the quartz wafers having a biconvex type and bat metallic electrodes with the sine ripple on the surfaces of the quartz wafer are used. The resonance frequency was analyzed by three-dimensional Finite Element Method and the results are compared with the theoretical values whenever they are available. Using low-cost oscillators connected to a microcontroller, a precise measurement system of temperature is implemented. Experimentally, the accuracy of measurement is better than 0.05 degree C (The errors include non-linearity, reproducibility and influence of load temperature) over the temperature range -60 degree C to 200 degree C.
Design, modeling, and simulation of quartz-crystal-tuning-fork-resonators-based micro temperature sensor
Author(s):
Jun Xu;
Rongqiang Chi;
Bo You;
Xin Li;
Haiying Wang;
Hong Ai
Show Abstract
The miniature frequency-temperature sensor based on quartz tuning fork resonators with a new ZYtw-cut and vibrating
in the flexural mode has been described. The resonance frequency of a quartz tuning fork crystal was comprehensively
analyzed by an analytical method, Sezawa's approximations and the finite element method. The influence of the sensor
structural dimension on the resonant frequency and structural modes is investigated, which offers reliable basis for the
structure design tuning fork geometry, tine electrode pattern and thickness of the micro quartz crystal tuning fork
temperature sensor. The validity of calculated and simulated results is experimentally confirmed. The experimental
results has shown that this new type of sensor with sensitivity about 0.001 degree C and accuracies 0.05 degree C
within temperature range from -50 degree C to 200 degree C.
Study of piston pressure sensors applicable for strength-electricity property tests
Author(s):
Guoan Wang;
Zhende Hou
Show Abstract
The property that the electric potential results in bone from strain of bone under stress is termed as the stress generated potential of bone. It is a key project to develop the piston-type pressure sensor for the experimental research into the stress generated dynamic potential in bone. The piston-type pressure sensor as a device to apply and measure force making it a key part for the whole research project. The current paper presents the research principle of the piston-type pressure sensor, the derivation of the relation between strength and strain and the technology for attaching and hardening the strain sheet.
Mechanism and kinetic characteristic of intelligent magnetic fluid acceleration sensor
Author(s):
Dong Cao;
Guixiong Liu;
Taobo Chen
Show Abstract
Traditional cantilever accelerometer generally has the problems of mechanical friction and the distort invalidation of elements which the magnetic fluid (MF) acceleration sensor presented in this paper utilizing a moving magnet fully suspended in MF could solve. This MF sensor is simple in the mechanism with controllable measurement range and precision. The moving magnet was balanced by the repulsive force of magnet in axial and MF second-order buoyancy in radial respectively. Its sensor model was brought forward and simplified to obtain its mathematical model. The MF magnetoviscous property that can realize the controllability of viscosity was discussed. The relations of sensor kinetic characteristic to various parameters including MF viscosity, acceleration and magnetic field energy were analyzed. The results show the moving trend is uniform under different acceleration. Through adjusting the magnetic field intensity to modify MF viscosity, it will get good astringency and keep balance time within 0.2s.
Human movement tracking based on Kalman filter
Author(s):
Yi Zhang;
Yuan Luo
Show Abstract
During the rehabilitation process of the post-stroke patients is conducted, their movements need to be localized and learned so that incorrect movement can be instantly modified or tuned. Therefore, tracking these movement becomes vital and necessary for the rehabilitative course. In the technologies of human movement tracking, the position prediction of human movement is very important. In this paper, we first analyze the configuration of the human movement system and choice of sensors. Then, The Kalman filter algorithm and its modified algorithm are proposed and to be used to predict the position of human movement. In the end, on the basis of analyzing the performance of the method, it is clear that the method described can be used to the system of human movement tracking.
Signal analysis for a semi-active suspension isolation system
Author(s):
Tao Sun;
Fanbing Li
Show Abstract
This paper proposes a method of signal analysis for a semi-active suspension isolation system. A semi-active suspension isolation system is an efficient equipment for vibration isolation and noise reduction in a car. In order to achieve a good vibration isolation effect, it adjusts its damping characteristic according to the excitation signals caused by different road conditions. Thus the key technique of the control of a semi-active suspension isolation system is to classify the excitation signals and analyze them quickly in time. This paper puts forward a signal processing method for these signals. At first, these signals are subdivided into three types, the stationary signal, the non-stationary signal and random signals. Subsequently, it uses the short-time Fourier transform (STFT) to handle them with different window functions in order to find the main frequency of the signal. Especially, the dynamic trend of the main frequency has to be considered for non-stationary signals. The two main parameters of the main frequency of the excitation signal, namely the position and the amplitude, will be obtained by the signal analysis. Then the control system can use them to give the best damping ratio for the damper. Finally, the method is used in a two-stage semi-active vibration isolation system to verify its effect. The experimental results show that it can analyze the signal exactly in time, and obviously enhance the vibration isolation performance of the semi-active suspension isolation system.
Temperature and displacement measurement system with fiber optic sensors for turbine blades
Author(s):
Yutian Wang;
Yongjing Zhu
Show Abstract
In this paper, a novel technique is presented to measure temperature and axial displacement of turbine blades simultaneously with a single sensor probe, by using non-contact measurement method. The heat radiation property of high temperature objects and the principle of optical fiber transducers in pyrometry are described. Based on the basic principle of colorimetric measurement, a fiber-optic temperature sensor is selected, in view of its high measurement accuracy and practicability, which is suitable for hostile environments. For dynamic external surface measurement, a new reflective intensity-modulated displacement sensor with a simple and reliable structure is proposed. In this project, the main elements for the sensor, circuit system and single chip ADuC848 are discussed. Especially, a concentric multi-circle fiber bundle is used in the sensor probe, which is designed on the basis of the required temperature measurement range and displacement measurement range.
A fluorescence high-temperature sensor based on fluorescence lifetime
Author(s):
Jinling Wu;
Yutian Wang;
Xinian Wang
Show Abstract
A kind of fluorescence optic-fiber temperature sensor is devised based on the alexandrite crystal. In this system, a new optic- fiber probe fabrication techniques is proposed. This system is particularly adapted to the temperature measurement in the range of room temperature to 650°C. During the cause of experimentation, using the PLD-PMTR (termed the Pulse Modulated Phase-locked detection with Two References) signal processing scheme. This temperature measurement method is proved to be effective and useful for its highly resolution and precision. It ensured the detected fluorescence signal to noise ratio was high enough to be measurable when the temperature is raised to 650°C.
A fluorescence optic-fiber temperature sensor based on crystal LiSrAlF6:Cr3+
Author(s):
Jinling Wu;
Yutian Wang;
Wanming Liu
Show Abstract
A kind of fluorescence optic-fiber sensor is devised based on the crystal fluorescence material. The characteristic of fluorescence material absorption and emission is analysis, and the optic-fiber temperature measurement probe based on LiSrAlF6:Cr3+ is developed. This system is particularly adapted to the temperature measurement in the range of 20°C to 50°C. During the cause of experimentation, this temperature measurement method is proved to be effective and useful for its highly resolution and precision.
Temperature measurement through wireless sensor networks
Author(s):
Shuai Chen;
Xianxin Zhong;
Lingling Chen;
Xiaowei Liao
Show Abstract
Wireless sensor network is a novel network with a large of nodes through wireless communication for information measurement in distributing area. The temperature measurement through wireless sensor network can get temperature in distributing area without costly infrastructure. In order to realize temperature measurement in wireless communication, the wireless sensor network technology is utilized in the measurement. The wireless sensor node with Atmega128L is introduced. The sensor ERT-J1VR103J is used to induce temperature. The performance of temperature sensor is analyzed. The temperature is gotten by the microprocessor Atmega128L, and then is sent through radio chip CC2420. The wireless sensor network operation system TinyOS is used in the application. The wireless gateway node based on GPRS is utilized in the remote wireless temperature measurement system through Internet network. The user node receives data from gateway to acquire temperature. The experimental result is gotten and the accuracy of temperature is 0.1 Celsius degree with relative accuracy is 0.1 percent. The result indicates that the temperature measurement system through wireless sensor network is reliable, convenient, and low cost.
Research on the improvement of traditional dial instrument precision based on C8051F020.
Author(s):
Guiling Sun;
Yi Liu;
Li Lu
Show Abstract
Two essential parameters to weigh the quality of a reinforcing steel bar are the value of its bending force and the maximum pull it can withstand, in order to measure them with higher precision, it is significant to describe the changing tendency of force with time and displacement by drawing a real-time curve directly during the process examining the quality of a bar when the pull exerted is variable continuously. Using C8051F020 as the core component, this paper improves traditional dial instruments whose precision can only reach the second level. Adopting a high precision pulling/pressing force sensor, an amplifier, a two-order Butterworth low-pass filter and a 12-bit AD converter which is in the C8051F020, the first level of precision can be obtained. A rotary encoder is used to measure the length increment of the bar during the pulling process, based on an algorithm, a force-displacement (or time) curve which is quite important for operators to control the course of experiment can be displayed on the LCD. Meanwhile, real-time experimental data can be stored in local flash, or uploaded to PC by RS-485 and stored in the center database. A real-time clock is also adopted to mark the time of each experiment that is useful to index the data. The measure system we describe here is characterized by simple structure, high precision and stabilization, and
convenience operation, can be used in other actual measure systems by only changing the front sensor, so it is of great
value of application and popularization.
Application of a fuzzy decoupling control algorithm for simultaneous control of both temperature and humidity
Author(s):
Jian Wang;
Qiming Xu;
Tinggao Qin
Show Abstract
It was introduced in this paper that a multi-mode control algorithm of PI-Single Neuron based on fuzzy decoupling, this control algorithm can be easily implemented by microcontroller in control systems of temperature and humidity. Under such control system, temperature and humidity are influenced each other. In order to remove the coupling, a new decoupling method is presented, which is called fuzzy decoupling. The static decoupling control is proven very effective when the system is in a static state. But it is not suitable to time-variant systems. In order to reduce the effect in a dynamic state, based on the static decoupling method, a loop is added to modify the decoupling coefficients. The fuzzy controller input is the control object's error of the influenced loop, while the system outputs are the decoupling parameters. The corrected parameters are constantly operated in the decoupling algorithm and the temperature and humidity control system are divided into two relative independent loop systems. Through fuzzy decoupling mentioned, we can use a multi-mode control algorithm of PI-Single Neuron for single loop of temperature and humidity. The PI-Single Neuron control algorithm is composed of PI algorithm and single Neuron algorithm. Different algorithm is chosen according to the absolute of error. The paper gives the structure of single neuron controller and it's simulation results. The paper also provides the simulated output response curves with no decoupling control, static decoupling control and fuzzy decoupling control. As the control algorithm which combines PI control with the single neuron control has strong robustness, good adaptability, excellent anti-interference ability, it is apt to real time control.
Development of a two-dimensional optical accelerometer using a DVD pick-up head
Author(s):
Chih-Liang Chu;
Cha-Hao Lin;
Kuang-Chao Fan
Show Abstract
This study develops a low-cost, highly sensitive two-dimensional optical accelerometer based on a commercially available DVD optical pick-up head. Vibrations of the structure of interest cause a change in the angle of the seismic mass within the accelerometer. The relative movement between the seismic mass and the base produces a change in the distribution of a focused light spot on the surface of a four-quadrant photodetector. The resulting change in the voltage signals output by the photodetector is then used to calculate the corresponding acceleration of the base. The experimental results indicate that the sensitivities of the accelerometer in the X- and Y-axis directions are 22.9 V/g and 21.3 V/g, respectively.
Machine tool 3D volumetric positioning error measurement under various thermal conditions
Author(s):
O. Svoboda;
P. Bach;
G. Liotto;
C. Wang
Show Abstract
To manufacture good quality or accurate parts, the measurement and compensation of three dimensional volumetric positioning errors of a machine tool are very important. Using a conventional laser interferometer to measure the straightness and squareness errors is very difficult and time consuming. Recently, Optodyne has developed a laser vector technique for the measurement of 3D volumetric positioning errors, including 3 linear displacement errors, 6 straightness errors and 3 squareness errors in a very short time. Using this laser vector technique combine with the data obtained from a set of thermocouples placed at key locations of the machine tool structure, the relations between the machine temperature distribution and the 3D positioning errors can be measured and modeled. The results can be used to compensate the 3D volumetric positioning errors under various thermal conditions. Reported here are the definition of the 3D volumetric positioning errors; the basic theory and description of the laser vector technique; the temperature sensors and the laser vector technique measurement results obtained on a vertical CNC machining center under different spindle load, machine temperature and environmental temperature.
H(infinity)-based active microvibration control of an ultra-precision machine tool
Author(s):
Liping Chen;
Chunliang Zhang
Show Abstract
A 6-degree-of-freedom microvibration isolation system for an ultra-precision machine tool has been developed. This system uses four air springs as passive vibration isolation elements and eight giant magnetostrictive actuators as active vibration isolation elements. Four vertical actuators and air springs are set in parallel to make use of the giant magnetostrictive actuators effectively. The displacement and velocity of the ultra-precision machine tool are chosen as the output feedback variables for the controller. The H(infinity) control approach is used to design the active vibration control system. Computer simulations and experiments are carried out to verify this system's microvibration control performance. The simulation and experimental results show that the developed active vibration control system has good isolation performance against the floor disturbance over wide frequency area.
Intermittent process measurement and process capability analysis using MP700 touch trigger probe on a CNC machining center
Author(s):
Fang-Jung Shiou;
Po-Chuan Su
Show Abstract
This study developed an intermittent process measurement system by integrating a MP700 touch trigger probe system with a machining center to measure a workpiece containing freeform surface and regular geometric features, and to do the statistical process control analysis. The whole measuring system, consisting of a personal computer, a CNC machining center controller, a RENISHAW MP700 touch probe system, was integrated information-technically. Measuring software was also developed to simulate the measuring path, to prevent collision, to generate the corresponding measuring NC codes and to calculate the process capability indices, such as the process capability index (Cp), the process performance index (CPK) and the accuracy capability index (Ca). To evaluate the performance of the developed measuring system, a carrier combined with a freeform surface and regular geometric features, referred to in the ISO 10791-7 cutting test standard, was designed. Six pieces of the tested carriers were manufactured and inspected using the MP700 touch trigger probe to evaluate the performance of the developed measuring system. According to the measuring results, the developed measuring system was successfully and effectively used to carry out the intermittent process measurement and the statistical process analysis of the measuring results of some test carriers on the machining center.
Hybrid HMM/SVM method for predicting cutting chatter
Author(s):
Yongtao Jiang;
Chunliang Zhang
Show Abstract
According to the properties of cutting chatter, a new chatter forecast system has been developed based on Hidden Markov Model (HMM) and Support Vector Machine (SVM). This system uses HMM as the recognition method and SVM as the prediction method. At the same time, means like wavelet package decomposition are also employed to extract the cutting features. The basic idea and general steps of this method are as follow. Firstly, the cutting signals are analyzed step by step in the same interval using wavelet packet decomposition. Secondly, the energy in every spectrum section are calculated and scaled in order to get general property. As a result, the energy distribution information and energy transition curve of different spectrum section can be retrieved. Then, SVR algorithm is applied to predict the trend of energy transition. The results, after scalar quantized, at last are input into HMMs to determine whether in chatter period. Certainly, current state still needs to be distinguished. The simulation results indicate that the new predicting method has good discriminating performances and high forecast accuracy.
Research on torsional vibration noncontact measurement of rotary machine
Author(s):
Zong Meng;
Bin Liu
Show Abstract
Based on laser Doppler effect, single section rotational speed of a rotating shaft was measured. By measuring the two sections rotational speed, the difference of the rotational speed between the two could be made. Integrating the rotational speed difference, the relative torsional angle of the two sections under the action of torsional virbration was received, so the rotating shaft torsional vibration was gotten. Non-contact torsional vibration measurement of rotary machine was achieved. The system was designed and the experiment was done on the torsional vibration experiment equipment. The result of experimentation indicate that the relative error between Laser Doppler and conventional torsional vibration measuring method that was less than 0.2%, and the measurement accuracy of Laser Doppler was high.
Anti-interference of the tribological test-bed for thrust bearings used in submersible pumps
Author(s):
Jianwei Yu;
Tao You;
Xiaofen Yu;
Minghua Jiao;
Ting Xie
Show Abstract
This test-bed was developed to investigate the tribological behavior of the thrust bearings - the key parts of submersible pumps, in the simulating work conditions in oil well. A great deal of Electromagnetic Interferences (EMI) are unavoidable and will lead to system failure or abnormal data in condition of quite high load and speed. On the basis of analysis and investigation of interference source and mode in system, such as power interference, vector control inverter, mechanical contact, static interference and so on, propose several hardware case, such as new power EMI filter, electromagnetic shielding, RC link, impedance matching, etc., were employed, and novel digital filtering algorithm, in measurement and control system of test-bed. The results showed that the combination of the different anti-interference methods can reach optimal reliability and precision.
Topography measurements and applications
Author(s):
Junfeng Song;
Theodore Vorburger
Show Abstract
Based on auto- and cross-correlation functions (ACF and CCF), a new surface parameter called profile (or topography) difference, Ds, has been developed for quantifying differences between 2D profiles or between 3D topographies with a single number. When Ds = 0, the two compared 2D profiles or 3D topographies must be exactly the same (point by point). A 2D and 3D topography measurement system was established at NIST. This system includes data acquisition stations using a stylus instrument and a confocal microscope, and a correlation program using the proposed parameters Ds and the cross-correlation function maximum CCFmax. Applications in forensic science and surface metrology are described; those include profile signature measurements for 40 NIST Standard Reference Material (SRM) 2460 standard bullets, and comparisons of profile measurements with four different techniques. An approach to optimizing the Gaussian filter long wavelength cutoff, λc, is proposed for topography measurements.
Surface topology from multi-angular reflectivity
Author(s):
A. K. Forrest;
R. S. Lu
Show Abstract
A surface scanner has been developed which records the light from an approximately flat surface at up to sixteen different angles. The scanner simultaneously records images of the surface as an illuminated spot is traversed across the surface. The optical design of the scanner allows the use of just one parabolic mirror slightly larger than the scan length required, and small detectors for the reflected/scattered light at each angle. Design principles for the scanner are developed and some resulting images on surfaces presented. The data from the above scanner is used to compute the surface topology of a surface by integrating the surface slope measurements obtained from the multi-angle data. This is accomplished by obtaining an estimation of surface slope at each pixel position. Constraints are then imposed on the data to obtain a continuous three-dimensional surface. The surface obtained is compared with data obtained from the surface by measuring with a "Talysurf" stylus measurement machine. To do this a common coordinate frame is needed requiring a rotation and scaling in two directions of one of the data sets to obtain maximum cross-correlation between the three dimensional profiles.
Geometrical information extraction from laser speckle pattern images using texture analysis
Author(s):
Rong-Sheng Lu
Show Abstract
In this paper, the statistical properties of speckle pattern are investigated from the point of view of computer texture analysis, and a measurement method of an object surface roughness and the object surface displacement is subsequently put forward. In the geometrical information extraction technique, the speckle pattern images are taken by a very simple configuration of setup consisting of a laser and a CCD camera. Surface roughness and displacement information is extracted based on the energy feature characterization of the grey level co-occurrence matrices of the speckle pattern images. Our experimental results show that surface roughness and displacement contained in surface speckle pattern images have a good relationship with their energy feature. By means of a set of standard surface specimens with different roughness, the relation curve is readily calibrated. Then the surface roughness of an object surface made by same material and manufactured by the same way as the standard specimens can be evaluated from a single speckle pattern image taken from the surface. Similarly, the surface displacement can also be obtained from a single speckle pattern image. The easily implemented method can be used in-process surface roughness and displacement measurement.
Comparison between ASME and ISO standards on surface texture
Author(s):
Kai Hu;
Xiangqian Jiang;
Xiaojun Liu;
Zhengao Xu
Show Abstract
Surface texture is generally a significant technique requirement of high-tech products. Surface quality information can usually play an increasing role in achieving interoperability among existing products, create order in markets, simplify production and ensure safety. As the most authoritative standard organizations, ASME and ISO services are used throughout the world, their codes and standards influence global manufacturers and consumers. ASME B46.1 is one of many vital tools to promote surface measurement techniques, while ISO has a set standard system for surface measurement, analysis and evaluation. This paper compares the ASME B46.1 (2002) standard (Surface texture: surface roughness, waviness, and lay) with ISO 3274 (1997) standard on methods of surface profiles filtering. It preformed the present research in order to show the latest developments of the ASME B46.1 (2002) in the regime of contact profiling techniques where the degree of measurement control is highly advanced, and a large range of other techniques that present valid and useful descriptions of surface texture. Also, this paper shows the differences of terms, definitions and surface texture parameters between ASME B46.1 (2002) and ISO 4287 (1998). The different evaluation results have been calculated based on above two standards for the same surface data. Obviously, it is necessary to consider the divergence above to develop China's standards (GB) on surface texture.
A three-dimensional precision platform based on vertical scanning and its application in surface topography measurement
Author(s):
Yurong Chen;
Xudong Yang;
Tiebang Xie
Show Abstract
The measurement and characterization of three-dimensional surface topography is representative of a primary development direction of surface metrology. This paper presents a three-dimensional precision platform based on vertical scanning that has practical application in surface topography measurement. The three-dimensional precision platform is composed of a two-dimensional platform with metrology system and a vertical scanning platform. The vertical scanning platform is laid on the two-dimensional platform with metrology system. When the workpiece is measured, the closed loop control system controls the two-dimensional platform. Meanwhile, the Z direction servo motor and the piezoelectric actuator drive the vertical scanning platform to move vertically to realize the coarse and fine displacement. The diffraction grating displacement sensor detects the vertical relative displacement. So the precision positioning in X-Y direction is obtained and the vertical scanning in Z direction is realized during the surface topography measurement. The three-dimensional precision platform based on vertical scanning developed in this paper, as one of the key techniques, is the technique foundations for development of the improved contact or noncontact three-dimensional topography profilometers.
The application of watershed segment method in the characterization of 3D motif
Author(s):
Shenghuai Wang;
Tiebang Xie
Show Abstract
Surface topography characterizing and assessing method in 3D is a research hot in surface metrology field. The 3D-Motif characterization method presented by F.Barre is an extension of 2D-Motif method. This 3D method is not practicable for the 3D grid sample data when the sample spacing is not small enough. For the limit of this characterization method, this article characterizes the 3D surface topography of 3D engineering surface with electron microscope image. The electron microscope images of fine processing workpiece surface topography with two kinds of machining methods are sampled. These images are gray images and denote the height of every point of the workpiece surface. To avoid the sample spacing limit of 3D surface topography with grid sample data, the watershed segment method is introduced to dispose the 3D surface topography images and used to segment those electron microscope images. Watershed segment method is a new image segment method, which is based on the topology theory of mathematic morphology. The basic idea of this method is to take the image as the topology relief of geodesy; the gray level of every pixel in the image denotes the elevation of the correlative point. Last, according to the parameters of 3D-Motif, this article characterizes the 3D surface topography of workpiece surface with two kinds of processing methods. The corresponding disposed images and final results are presented in this article and to provide a criterion for assessing the surface topography with different machining methods.
A measuring system for surface roughness parameters
Author(s):
Jinhong Han;
Yunkai Wang;
Xianfeng Zhang
Show Abstract
We designed a measurement and control system which can measure the surface roughness parameters with a Single Chip
Micyoco (SCM) as its kernel. It uses an inductive transducer to pick up the data. The instrumental structure and the
working principle are also introduced in this paper. The integrated hardware and software systems have been designed
and improved. The prototype model was calibrated and the instrumental precision was analysed according to the
measured data. In this system the surface roughness parameters can automatically be measured and controlled, such as
data processing, determination of the reference line, disposal of the surface profile informations, display and print of the
results etc.
Fractal anaylsis and modeling for NiCrAu MEMS micromirror surfaces
Author(s):
Xiaodong Xu;
Yuan Luo;
Yi Zhang
Show Abstract
Micro-mirror is the key structure of MEMS optical switch, Digital Mirror Display (DMD) and variable optical attenuators. Surface roughness plays a crucial rule in reflectivity, insertion loss, and all kinds of surface forces. For describing the topography of surfaces, there are several roughness parameters. Some parameters depend on sample size and instrument resolutions while fractal theory, which is characterized by continuity, non-differentiability and self-affinity, shows its complementarities. In this paper, the topographies of various micro-mirror surfaces are measured by Scanning Tunneling Microscope (STM). Then, these rough surfaces are charactering by a fractal theory, and a three-dimensional Weierstrass-Mandelbrot function is applied to simulate the topography of the rough surfaces. The result shows that the Weierstrass-Mandelbrot function is efficient in creating models and analysis the topography of MEMS surface. It will be very useful in the future researches.
Surface detection based on single fringe pattern analysis
Author(s):
Tingrui Liu;
Ailing Gong;
Yongrui Zhao;
Guangqing Chen
Show Abstract
The optical surface metrology based on interference pattern analysis has been one of the study subjects that draw
people's attention for a long time. The paper illustrated a study that improved FFT precision by revising exterpolation
algorithm of single interference pattern, simulated different Spatial Carrier Phase Shift (SCPS) algorithms, on the basis
of correlative literature, and analyzed error contrast. Finally, the paper established FFT, revised 5-point algorithm and
N-point algorithm as real-time analysis approaches of single interference pattern.
Use of least square support vector machine in surface roughness prediction model
Author(s):
Hua Dong;
Dehui Wu;
Haitao Su
Show Abstract
This paper aims to introduce a novel model into prediction field for surface roughness in machining process, and report the results of comparison between the novel model and the other two prediction models in the experiments that have been examined. The novel model is based on least square support vector machine (LS-SVM), while the other two models are based on BP neural network and standard support vector machine (SVM) respectively. In the study, 54 groups of data about surface roughness and four kinds of parameters were obtained by full factorial experiments. And then, the data were analyzed by contrast experiments: set up prediction models with BP neural networks, standard SVM and LS-SVM respectively. The results have indicated that the mean deviation of LS-SVM model is only about 25% of that of SVM method, and 2~3 orders smaller than that of BP method. Furthermore, it takes the least time to set up the models by LS-SVM model among these approaches. In summing up it may be stated that the proposed model is faster in speed, higher in accuracy, and more suitable for prediction of surface roughness.
Noncontact measurement of irregular reflective surfaces
Author(s):
X. Liu;
Y. Gao
Show Abstract
A pencil beam interference based slope measurement method is investigated. A new pencil beam generator design, which consists of a single parallel plane plate made of calcite crystal, is proposed. The generator is simple and compact in structure. It is convenient to use for adjustment and has high stability. Based on the generator, a new pencil beam interferometer for surface slope and normal vector distribution measurement is developed. A new method for surface normal vector abstraction from interference patterns and a new algorithm for surface reconstruction from the surface slope and normal vector distribution data are proposed and examined. Experimental testing results are presented to verify the proposed design and methods for irregular reflective surface measurement.
Technology of freeform surface reconstruction from laser scanning point cloud based on nonuniform B-spline
Author(s):
Yingfu Guo;
Zhuangde Jiang;
Xiaoqiang Wang;
Bing Li
Show Abstract
The point cloud data on a scanning line from laser scanning system has the same value in one dimension. According to this characteristic, an algorithm of surface reconstruction based on non-uniform B-spline is put forward. For the pre-processing of the original point cloud, the points that don't belong to the surface are deleted, and the methods of splitting, sorting and slicing are used. The least square non-uniform B-spline is used to smooth and interpolate the data of the section point cloud, then the data of reconstructed surface can be achieved after a secondary sampling. An example of the rearview mirror of motorcycle is given to testify that the method is effectual and feasible.
Data processing for measuring tread contour of a train wheel based on computer vision
Author(s):
Qiancheng Zhao;
Shanxi Deng;
Yingfu Guo;
Yongyue Yang
Show Abstract
Dimension and form of a train wheel tread contour are the key controlled parameters in manufacturing and running process. Projecting laser light line to the tread contour, the left image and the right one of the light line in the measured countour are caught by using two CCD cameras. After calibrating the two images and other processing, the two images are pieced together to form a free-form curve. Measuring and data processing are completed in two steps as using "Bi-measurement Evaluation Test", the first step is modeling and the second is testing. Comparing the real coordinate values of Testing points with their theoretical ones reconstructed from the form model, the problem whether the model expresses the contour features enough can be resolved. If the answer is yes, the number and position distribution of sampling points are rational, then we can estimate the standard deviation (σ) of noise in the measuring sequence made up of coordinate values of sampling points. The fact that the standard deviation (σ) of noise in the real measuring sequence is about 0.1600mm is estimated by real measuring and data analysis.
Surface faults evaluation by optical imaging method for electropolishing process
Author(s):
Shuo-Jen Lee;
Jing-Jang Lai;
Dar-Yuan Chang
Show Abstract
The electropolishing process is a surface treatment technology which results in smooth and shining surface and high corrosion resistance film. Methodology of evaluating the surface quality is important in finding the optimal process parameters. In this paper, an evaluation method by using optical imaging method is proposed to characterize and evaluate the surface faults. The results demonstrate the optical images are more sensitive in characterizing surface topology. The variation in the calculated ratio of the faulted surface area is sharper then the value of surface roughness.
Research on anisotropy of measurement for complex curved surfaces
Author(s):
Zhaoyao Shi;
Jie Tang;
Xiuming Li;
Xiaowei Wei
Show Abstract
This paper presents for the first time the concept of anisotropy of measurement for complex curved surfaces. Based on the theory of differential geometry, the relation between measurement error and micro-structure & form of curved surfaces is studied, which is existence proof of anisotropy, and also the basic rule of anisotropy is clarified. Through anisotropic analysis of the measurement for complex curved surfaces, series of conclusions relating to that are obtained. Those conclusions have not only theoretical meaning but also far-reaching practical value on the following aspects: precision instruments design, error budget, measuring method design, and etc.
Application of data fusion to environmental measurement in coalmine
Author(s):
Hua Fu;
Ming Hua
Show Abstract
There are many factors which affect coal production processes and the safety of colliers in coalmines. Among them, there are especially three key factors, the temperature T, the atmospheric pressure P and the gas concentration C that need synthetically to be considered. However, the conventional strategies of environmental measurement only considered the effect of T, P, or C without any systematic, therefore there have been difficulties to make a comprehensive evaluation. Accordingly, the authors present a new method based on a secondary data merging mathematical model which synthetically considers the influences of T, P, and C with an adaptive-weighted data fusion method based on the Dempster-Shafer evidence theory, leading to an optimization of the environmental measurement parameters. This method not only ensures the completeness of the data source but also improves the accuracy of the detection systems for a coal mine. It especially enables a new exploration and research about environment detection processes.
Measurement of helical surface
Author(s):
Yangkuan Guo;
Lianqing Zhu;
Zhaoyao Shi;
NaiguangLi Lv;
Mingli Dong;
Qingshan Chen
Show Abstract
The measurement of helical surfaces is used not only to evaluate the precision of the surfaces, but also to analyze the sources of its deviation from the specification. In this article, many aspects of helical surfaces are contained, as the mathematical principle of forming the surface, the measuring equipment, the measuring methods and our research status. First the forming principle of the helical surface is given and the classification methods by the mathematical equations are shown. Then the equipment is summarized, and the classification and the working principles of the measurement of the helical surface is given. At third we introduce our research status, and also give a measurement example of a hobbing cutter and a concise analysis. From the analysis we derive a method to improve the quality of the helical surface. Finally, we discuss the future development of the measurement of the helical surface.
A uniform model for the evaluation of deviations from helicoidal surfaces
Author(s):
Lianqing Zhu;
Zhaoyao Shi;
Mingli Dong;
Qingshan Chen;
Yangkuan Guo
Show Abstract
In this paper we propose a uniform mathematic model of helicoidal surfaces. We describe the spacing surface and the properties of helicoidal surfaces. We studie the description of real surfaces and on this basis, we derive the deviations from helicoidal surfaces and its uniform model. We provide an algorithm for the compensation of the stylus radius. This research is useful to unify the measurement of all kinds of helicoidal parts and to simplify the measuring procedures.
Novel design for antidazzle vehicle headlight
Author(s):
Liandong Yu;
Yetai Fei
Show Abstract
Compared to the important role in night driving of vehicle headlights, the dazzling and discomfort problems caused by the headlights are also not ignored. Sometimes the dazzling light is the main factor of causing traffic accidents in the night. In the paper, a novel design using irregular coating mirror to solve the dazzle problem is brought forward. As for the traditional headlamp comprised of a high beam and a low beam filament, the high beam filament causes plenty of the dazzling light. If the high beam filament's lighting density can be reduced without influencing the lighting effect, the problem is to be solved. Because plane-reflect mirror can change the light's transmitting direction, we employ the plan which uses 88 slat glasses whose upper surfaces coated with reflection films and bottom surfaces with light absorbing films, and put the whole mirror in front of the headlamp. When turn on headlight, the dazzling light is reflected by glass' upper plane, then absorbed by bottom plane. So the mirror prevents people from the dazzling light. In addition, the paper presents the experiment results to prove the anti-dazzle effect.
Inspection and recognition of missed needle roller bearings based on image
Author(s):
Tao He;
Wenjun Wu;
Qinghua Wu;
Wei Li;
Mingan Xia;
Li Chen
Show Abstract
In this paper, a missed needle rollers inspecting device and a missed needle rollers recognizing algorithm, which are
based on mechanical vision technology, are introduced. The cores of this system are image acquisition devices and image
processing. The image acquisition system is composed of a CCD, lens, low angle light resource, image acquisition card,
and mechanical position. The image processing procedure includes conditioning module, image partition module, image
searching module and the number of needle rollers recognizing module. According to the results of dynamic and static
testing, a method synthesizing the static and dynamic image acquisition is selected. Meanwhile, the specific parameters
of image acquisition and steps of image processing are established. The machine vision technology is used to find the
missed needle rollers, the speed of inspecting is promoted, and an automatically, non-touched and online inspecting
system is realized.
Planar straightness error evaluation based on particle swarm optimization
Author(s):
Jian Mao;
Huawen Zheng;
Yanlong Cao;
Jiangxin Yang
Show Abstract
The straightness error generally refers to the deviation between an actual line and an ideal line. According to the characteristics of planar straightness error evaluation, a novel method to evaluate planar straightness errors based on the particle swarm optimization (PSO) is proposed. The planar straightness error evaluation problem is formulated as a nonlinear optimization problem. According to minimum zone condition the mathematical model of planar straightness together with the optimal objective function and fitness function is developed. Compared with the genetic algorithm (GA), the PSO algorithm has some advantages. It is not only implemented without crossover and mutation but also has fast congruence speed. Moreover fewer parameters are needed to set up. The results show that the PSO method is very suitable for nonlinear optimization problems and provides a promising new method for straightness error evaluation. It can be applied to deal with the measured data of planar straightness obtained by the three-coordinates measuring machines.
Study on thermal deformation of cylindrical piece in steady temperature field
Author(s):
Zai Luo;
Yetai Fei;
Yi Lu
Show Abstract
Conventional theories are In the conventional theories and calculations of thermal deformation of cylindrical
piece in steady temperature field, thermal expansion coefficient, body form parameter and temperature are
considered. They are approximate and linear, can only be applied in normal or low precision field. An equation
for calculating thermal deformation of cylindrical piece in steady temperature field is deduced based on the linear
relation between linear expansion coefficient and bulk expansion coefficient. Results of theoretical and
experimental studies are presented, the experimental results also make it clear that the equation is more logical
than the traditional method.
3D reconstruction of micro surface based on optics technique
Author(s):
Y. B. Zhang;
H. Xiao;
F. Ji
Show Abstract
More and more precise parts are being required in modern domains of scientific research and manufacturing industry, which urges the corresponding measuring technologies to ameliorate and innovate, especially in micro-nanometer scale. The paper gives a detailed introduction about the optics interferometry and digital image processing technology respectively. Then, a 3D reconstruction method based on interferometry and image processing is described in the paper to solve surface measuring problem of a kind of planar part. The method can show the microcosmic surface of the part distinctly. At the same time, some parameters of the part can be calculated to reflect the manufacturing quality. According to these parameters, the conclusion on whether the part is qualified or not can be made, some another conclusion on how to modify the part for better result can also be determined. At last, some experiments have been done to verify the effect of the method. The method is simple, convenient and practical. Its measurement capability is between atomic force microscope and coordinate measurement machine.
The assessing method of complete tooth form error based on the spline function
Author(s):
Fugui Huang;
Changcai Cui;
Rencheng Zhang
Show Abstract
Having analyzed the shortcoming of current measurement method of involute cylinder gear wheel tooth form error and
the reason of error, measurement theory and implementation method of the complete tooth form error of the involute
cylindrical gear have been proposed; mathematical model of fitting actual tooth curve based on cubic spline function has
been derived and the determination of boundary condition has been given; feasibility of measurement and evaluation
method for complete tooth form error has been verified by experiment.
Research on the key techniques of form and position evaluation based on the genetic algorithm
Author(s):
Changcai Cui;
Bing Li
Show Abstract
The Evolutionary Algorithm (EA)-Genetic Algorithm (GA) was improved to evaluate the form and position errors that were summarized as nonlinear optimization problems. The key techniques in the implementation of the GA have been studied in detail. The emphasis was on the fitness functions of the GA concerned with the concrete problem so that they were proposed first. Second the expression of the desired solutions was discussed in the continual space optimization problem. Because different expression was suitable for different problem, here the real numbers were used to express the solutions to find which were called as chromosomes in the GA. Third the improved evolutionary strategies of GA were described respectively on emphasis. They were the selection operation of Odd Number Selection plus Roulette Wheel Selection, the crossover operation of Arithmetic Crossover Between Near Relatives and Far Relatives, and the mutation operation of Adaptive Gaussian mutation. The evolutionary strategies determined the update of the whole population and the terminal solution. After operations from generation to generation, the initial stochastic population on the basis of the least squared solutions would be improved until the best chromosome/individual appeared. Finally some examples were computed to verify the devised method. The experimental results show that the GA-based method can find the desired solutions that are superior to the least squared solutions and almost equal to those given by other optimization techniques except a few examples give a similar result.
Research on new method in separation of errors
Author(s):
Ge Zhu;
Min Wu;
DongLin Peng
Show Abstract
It is achieved satisfactorily to realize the separation of error signals with various frequencies by numerical fitting instead of digital filtering. It is proved that both numerical fitting and digital filtering are the same in essence through mathematical reasoning. During the process of reasoning the former with the theory of the latter, a new window function is obtained of which the shape is completely different from that of traditional window functions and has never been seen before. The entire reasoning process of it is given.
Analysis of a precise instrument for measuring reference level involute
Author(s):
Zhifeng Lou;
Liding Wang;
Xiaodong Wang;
Yong Ma;
Yuling Zhang
Show Abstract
Reference level involute is used for evaluating other involutes, but it is very difficult to measure reference level involute exactly. Nowadays the available methods for measuring precise involute include single base disc mode, electronic generation mode, and CNC three-coordinate mode. But measurement accuracy of the modes above is not suitable for reference level involute. A precise instrument for measuring reference level involute, double base discs instrument, is introduced. It is consistent with generation principle of the involute entirely. Besides having the advantages of single basic disc instrument, the instrument can remove Abbe error caused by the stylus, and has no pressure deforming. The instrument's structure is described. The main sources of measurement errors are analyzed and methods for compensation are presented. Finally, uncertainty of the instrument is given, which meets reference level involute test specification.
The new optimizing demodulation method of energy operator arithmetic and its comparison to Hilbert transformation
Author(s):
Min Wu;
Ge Zhu;
DongLin Peng
Show Abstract
The current main research aim of fault diagnosis is to find a new method which have more excellent integrated ability in such aspects as precision, sensitivity, reliability and compact algorithm and so on. Be enlightened from some phenomena on the analysis of the generating mechanism of speech signal, the energy operator separation algorithm (EOSA) is put forward as a new demodulation method. This approach uses a nonlinear differential operator, through optimizing difference equation: Choosing the unit impulse response length of filter and fixing the weighting coefficient for input points, a new approach that the optimizing energy operator separation algorithm (OEOSA) is obtained, and been compared with Hilbert transformation, finally, draw the conclusion that this arithmetic is a simple, fast, exact and instantaneousness strong method, Since Hilbert transformation could be applied to demodulation analysis for mechanical signal, so it provide this method could also be applicable for detecting machine equipment.
Propagation characteristics of ultrasonic guided waves in bolts embedded in soil
Author(s):
Yaxin Sun;
Cunfu He;
Bin Wu;
Xiuyan Wang;
Zenghua Liu
Show Abstract
The treatment of a bolt embedded in soil is simplified to the model of a rod embedded in an infinite medium. The dispersion curves of the model are calculated. Propagation characteristics of longitudinal modes in a free bolt and a bolt embedded in soil are studied. The longitudinal mode L(0,1) in a bolt embedded in soil in the frequency range from 40kHz to 90kHz the displacement of the profile is simple, which makes it easy to be excited. Its attenuation is the smallest in all modes, and its energy velocity is the fastest. This indicates that the longitudinal mode L(0,1) can be used for the inspection of a bolt embedded in soil. At the same time, the experiments on a 2 m long bolt embedded in soil, inspected by using ultrasonic guided wave have been carried out. The results of the experiment show, that the longitudinal mode L(0,1) in the frequency range from 40kHz to 90kHz is suitable for the inspection of a bolt embedded in soil.
A new method of simultaneously measuring the applanation force and area as applied to tonometer prototype
Author(s):
Xueyong Zhang;
Jianguo Ma
Show Abstract
A new method for simultaneous measuring the applanation force and area and a device based on this method are presented for intraocular pressure measurement. A photoelectric probe transducer acting as applalation area detector converted the diminished quantity of light returned from applanation surface of the cone prism into one electronic signal, and a micro strain gauge acting as applation force detector converted changing load related to the resilient force of the eye into another electronic signal. A 16-bit single-chip microprocessor with E2PROM in the electronic circuit played the role of a nucleus, which stored the program instructions and the interrelated data. Laboratory experiments were carried out on a stimulated cornea clamped in a Perspex chamber connected to a hydraulic manometer to obtain intraocular pressure at different levels. Preliminary trials were carried out comparing the values obtained with those of the Goldmann tonometer. Diminished quantity of the light is directly proportional to the applanation area of the cornea and the changing load detected by strain gauge is equated to the resilient force of the eye. A new kind of tonometer can be constructed based on this principle. Experimental results on a stimulated eyeball showed the present tonometer reading has good agreement with that of the Goldmann tonometer. Further study including clinical trials and application is required to evaluate the accuracy and usefulness of this method.
Measurement of electrical signals for build-up welding with trailing peening based on virtual instrument
Author(s):
Jianjun Hao;
Jichun Lu;
Jianchang Li;
Yuejin Ma
Show Abstract
Build-up welding with trailing peening can achieve dispelling residual stress, meliorating the structure of welding and improving the fatigue life and quality of welding through peening welded seam and heat-affected zone (HAZ) timely along with welding. Some studies have proven that the peening performance depends greatly on the temperature of welded seam and HAZ. In this paper, a set of temperature measurement system was designed by integrate sensor technology, computer technology, data processing method and modeling technology. In order to achieve gathering electrical signal, calculating temperature field and forecasting peening location, the virtual instrument programming language Labwindows/CVI was adopted to program data acquisition and analysis in software and PC, high-speed data acquisition card model AMPCI-9111, voltage sensor model KV25A/P and current sensor KA200V were adopted in hardware. The process can be summarized as follows:i) gather voltage and current data of build-up welding; ii) set up temperature field model of build-up welding; iii) offer the reliable temperature parameter for confirming the best peening opportunity. The build-up test was conducted and the results indicate that the system can be used to simulate temperature field and forecast the peening location and opportunity accurately.
A new method for linear camera calibration and nonlinear distortion correction
Author(s):
Jun Wang;
Naiguang Lu;
Mingli Dong;
Chunhui Niu
Show Abstract
Recent progress of images taken by non-metric digital cameras encourages amateurs to utilize it for 3D measurements, but also introduces the difficulties of calibration. The ideal camera projection model is based on the pinhole linear model which proceeds on the assumption that the object point, the perspective center of the lens and the ideal image point all lie on a straight line. However, real camera lenses introduce nonlinear distortions that affect the accuracy of the transformation unless proper corrections are applied. In this paper, we present a new camera calibration method adopting a linear projection model and a nonlinear lens distortion model. Experiments are conducted on real data to compare the proposed method with the non-linear bundle adjustment and DLT (Direct Linear Translation), which shows that the accuracy obtained with the proposed method is close to the former, and much higher than the latter.
A point matching method in photogrammetry for microwave antenna with nonmetric cameras
Author(s):
Mingli Dong;
Naiguang Lu;
Jun Wang;
Xiaojuan Qi;
Yunan Sun
Show Abstract
A point matching method in photogrammetry for microwave antenna with non-metric cameras is presented. The method with coded points and epipolar constrain is described. To solve the point matching in large measurement range, the idea of the dividing area is presented. The circular coded points as identifiers are used to identify different subareas, and subarea matching is preformed. Then, the measured points are matched with epipolar constraint in each subarea of left and right images. In order to reduce the influence of lens distortion to epipolar constraint, a control points grid as frame of reference is used to correct all image points using a distortion model. Experimental result indicates that this method is valid and reliable to reduce data processing time, and to improve image matching veracity and automatic degree. The points matching ratio is 100%. This method has provided one excellent solution for point matching problem in large object photogrammetry with non-metric cameras.
A novel detecting system with full fluorescent spectra for pesticides
Author(s):
Zhong dong Wang;
Ya Juan Zheng;
Gui cai Ruan;
Yu tian Wang
Show Abstract
A detecting system is developed applying the technologies of fiber-optic sensing, grating dispersion and multi-channel image sensing (Charge Coupled Device) based on the fluorescence mechanism of carbaryl. In this system, a pulsed xenon lamp is used as an excitation light source, optical fibers are selected to transmit and detect fluorescence, fluorescence dispersion is implemented with a small-sized flat field grating spectrometer and data gathering and A/D conversion are conducted with a high speed signal processing module. Moreover, the system is used to measure the fluorescence characteristics of carbaryl. The results show that a full fluorescence spectrum of carbaryl can be obtained in a single exposure under a UV excitation wavelength of 319nm, has a good linear relationship in the range of 4.0~100.0 ng/mL of carbaryl liquor and the minimum detecting limit is 4.0ng/mL with the linear correlation coefficient r being 0.9986. When this instrument is likewise applied for measuring carbaryl in river and ground water,the recovery may approach 100 %.
Study on the properties of flatness error objective function
Author(s):
Ping Liu;
Sha Wang
Show Abstract
Optimization algorithms are generally used to seek the minimal values of form error objective functions by iteration when a microcomputer is used to evaluate form errors of machine components by the minimum zone evaluation methods. The properties of such objective functions are very important for seeking the minimum zone values of error quickly and reliably. In this article, the unconstrained optimization model is established for assessing flatness errors by the minimum zone assessment method. The properties of the corresponding objective function are thoroughly researched. On the basis of the modern theory on convex functions, it is strictly proved that the established flatness objective function by the minimum zone assessment method is a continuous, non-differentiable and convex function defined on the two-dimensional Euclidean space R2. Therefore, the global minimal value of the objective function is unique and any of its minimal point must be its global minimal point. Thus, any existing optimization algorithm, as long as it is convergent, can be used to solve the objective function to get the reliable minimum zone flatness errors, without the possibility of seeking a value which is not in accord with the minimum zone for flatness. Two examples are given to verify the theoretical results presented.
Error separating and correcting method of nanometer two-dimensional working table
Author(s):
Hongtao Yang;
Yetai Fei;
Xiaohuai Chen;
Qi Wang;
Feixiang Jin
Show Abstract
The designing principle's analysis and the structure design using modern accuracy design concept of nanometer two dimension working table are introduced. The source of the uncertainty is overall analyzed. The error separating and correcting method is designed. The influence on the measurement result of the autocollimator and the interferometer produced by the angle error of the orthogonal prism is analyzed on principle. The preview experiments are done. The results indicate that the light path deflection using orthogonal prism has no influence on the error separating result, but without absolute zero position has obvious influence on the error separating result. The error correcting result shows that the precision demand of nanometer two-dimensional working table can be met.
A subpixel edge detection algorithm for the high precision automatic alignment system
Author(s):
Yuning Zhong;
Qinghua Lv;
Liangen Yang;
Yingwu Xue
Show Abstract
A new sub-pixel edge detection algorithm has been presented in this paper, which can be used in some high precision automatic alignment systems, such as automatic industrial measurement systems; integrate circuit encapsulation systems, micro-electromechanical systems, micro-optical electromechanical systems, three-dimensional encapsulation systems and so on. This algorithm uses the spatial moment to detect the location of edge within sub-pixel resolutions, and gains an advantage over the traditional pixel edge detection algorithms. Moreover, an extraction technology of region of interest is applied to reduce the time of analysis after rough pose estimation.
Application of watersheds algorithms to train wheel tread check and measure systems
Author(s):
Bangxing Shen;
Haibo Zhang;
Wei Wang
Show Abstract
A image system and a new kind of image processing algorithm (watersheds algorithm) are introduced; First, we get the prime wheel tread data by a Charge Coupled Device (CCD), after the pretreatment of the data, we use the watersheds algorithm to get the trail wheel abrasion and peel off strips, than we will get the numerical value of the damage. The result of the experiment shows that the system can obtain the edge of the trail wheel abrasion and peel off strips; the algorithm is fast, stable and anti-jamming; the recognition system can satisfy the manufactory requirements.
Tomography image processing techniques for geometrical characteristics measurement of viscous objects
Author(s):
Lifu Li
Show Abstract
The geometrical characteristics measurement of viscous objects is one of the development tendencies of dynamic geometrical characteristics measurement. This article deals with the technique of tomography image processing for geometrical characteristics measurement of viscous object. Based on the theory of photoelectric information processing, image segmentation, image preprocessing and object characteristic extraction from images are developed to increase the amount of information which can be obtained from viscous object images. The experimental results demonstrate that these methods cannot only distinguish the geometrical characteristics of viscous objects from tomography images in which the ratio of pixels between background and object image is about 9 to 1, but can also increase the image resolution by 30 percent. It is concluded that these methods can solve the problem to use computer tomography of dynamic geometrical characteristics measurement for non-destructive inspections.
Investigation of a 24-phase colour LED lighting source
Author(s):
Li Jun;
Hakiem Hsu;
Baofeng Zhang;
Horng-Shing Chiou
Show Abstract
The performance of a typical machine vision system depends on the quality of the images that is directly affected by the illumination. In order to obtain high contrast images, the target must be illuminated in such a way that distinctions between target areas and peripheral areas are as clear as possible. A good design can improve the resolution of images and make software programming more easy, while a bad design will inevitably cause many problems. For example, specular reflection and exposal may hide important information, and hatching will blur the edges of images. So we present a new design of a light source called 24-phase colour light and various lighting techniques to improve the quality of the illumination.
Error analysis of a reflector in total station angle measurement
Author(s):
Zhiguo Xia;
Yabo Luo;
Yong Zheng;
Huazhi Pan
Show Abstract
The total station has been widely applied in engineering and industrial surveying systems by which the distance and angle can be acquired automatically. In order to acquire a high accuracy in the measurement, it is one of the important points to select the right reflector and use a constant correction. But people usually pay more attention to the accuracy of the instrument than to the accuracy of the reflector. In this paper, the structure of the reflector and the error sources of the reflector are discussed and the error values of reflector are calculated. We analysed and tested all types of reflectors that are manufactured by Leica Geo-systems (general circle reflector, precision circle reflector, 360° reflector, ball reflector, tape) in the FAST paraboloid antenna model measurement in Miyun Beijing. The test result show that it is important to select the right reflector and give a precise correction for the total station to get a measurement result of high accuracy.
Calibration method of microscope and its measurement uncertainty
Author(s):
Jian-ping Bao;
Hui-sheng Wang;
Xiao-fei Zhang
Show Abstract
This paper introduces the working principle of Fibre Microscope and Metallographic Microscope, and their mutual calibration method. The calibration method is reasonable and easy to operate. Metallographic Microscope is widely used in metallurgy, manufacture, science and technology fields, and so on, for measuring the grain size of Austenite of metal material and the depth of Carburized layer after the heat treatment of the material. Fiber Microscope mostly measures the diameter, cross section and section acreage of all kinds of fibers. The key of the paper is to choose the best source of quantity values and the corresponding instrument. The quantity values of Fibre Microscope and Metallographic Microscope are traceable to the national standard. Moreover, the choice of suitable instrument can guarantee the quality control of the manufacturers.
Key technology of optical fiber level gauge optical antenna used for incident optical fibers
Author(s):
Zeng-yao Zhang;
Qian-min Mao;
Yi-bing Yan
Show Abstract
As the output power of the laser diode (LD) used in the level gauge is small and the reflected and incident beams is are required to be parallel, a cube corner reflector (CCR) is used as reflecting object. There is an inevitable cross shift 2Δℓ of the returning beams, as there is a linear moving error Δℓ of the CCR in vertical direction. The cross shift is the most difficult point for the measuring system. It would cause instability of the instrument, even make it stop working. To get as much light energy as possible, especially from the off-axis beam, into the receiving fiber, some characteristics and parameters of optical fiber are considered, as for example the numerical aperture NA. We designed a special optical antenna used to couple to the receiving fiber. This is a reflecting coaxial multilevel tapered optical antenna used in receiving telescopes. The working principle, design method and performance are introduced. Experimental results indicate, after the optical antenna is set, that even if the light spot drifted off the end of the receiving fiber by several centimeters in cross direction, the signal beam could still enter the receiving fiber. The optical antenna greatly increases the ability to gather the light beam and guarantees the stability of the instrument. Such optical antenna also could be used for laser range finders, Free-Space Optics and other optical fiber system.
Diameter detection and process quality prediction for optimal control of enameled wires
Author(s):
Hai-tao Su;
Hua Dong;
Bo Xu
Show Abstract
The quality of enameled wires impacts the reliability of motor products, wiring products and electronic products. The diameter of line-shape material usually is measured by means of photoelectricity energy, laser scanning, laser diffraction and projection imaging. A bi-light-source projection method was proposed by Zhao Bin etc., which measured 0.1-1.0mm diameter of enameled wires by using bi-refringent-crystal. A new method, single-light-source projection, is proposed in this paper. A beam from semiconductor laser light-source was disparted into two beams by Fresnel bi-prism. Then, the two beams projected onto an enameled wire and detected by CCD. The accuracy of the new method is much higher due to the magnified projection. Aiming at multi-factor input and nonlinear output of the enameled wires' production process, the RBF neural network was selected to pre-treat the process data obtained by our new method to set up dynamical training-set and predict quality. The simulation training results have proved that RBF neural network prediction method costs less training time, has less prediction errors and less samples. In summing up, it may be stated that single-light-source projection and RBF neural network prediction method are very suitable for real-time optimal controlling on enameled wires' production process.
A precision measurement sensor for measuring the critical water content of a plant
Author(s):
Dongsheng Li;
Manxi He;
Yifan Li;
Yupei Duan
Show Abstract
Two kinds of sensors were developed that can precisely measure a leaf's thickness. By an analysis of optic characteristics of the gauge head device, the actual transmission characteristic equation was established. The authors analyzed these precision instruments and carefully investigated the structural parameters related with principal error. Therefore, some schemes were proposed to reduce principal error and adjusted actual characteristic. This article also calculated the error resulting from contact deformation of the gauge head.
Parameterization of three-dimensional fluorescence spectra based on singular values and oils clustering analysis
Author(s):
Guangjun Tian;
Zhiyong Wang;
Xuhui Tang;
Yonghong Liu;
Jinshan Shi
Show Abstract
Depending on oil components, three-dimensional (3-D) fluorescence spectra of oils can be seen as their "fingerprints". Various kinds of oils can be classified by clustering their feature vectors. Statistic parameters such as the average, standard error, centroid, kurtosis, as well as geometrical distribution can be selected as the feature parameters of 3-D fluorescence spectra of oils forming the feature vector. In this paper, oil clustering based on parameterization using singular values of Excitation-Emission Matrix (EEM) of 3-D fluorescence spectra is studied as a progressive work for identification of complex contaminating oils in water. Clustering analysis of oil is completed with singular values forming the feature vector. As one of convincing results obtained by clustering analysis using Matlab tool, single values of the EEM have an advantage over those statistic parameters of apparent features of 3-D fluorescence spectra in classifying oils.
Numerical simulation on weight function of electromagnetic flow meter
Author(s):
Jingzhuo Wang;
Rongsheng Lu
Show Abstract
A new finite element procedure for the solution of the weight function, which represents the degree of the contribution of
the fluid velocity to the signal in the cross section of a pipe of electromagnetic flow meter, at every point of the cross
section of flow pipe of multiphase flow was presented. The solution of the weight function is important for the velocity
profile inversion process. First, a numerical simulation model was built up with Femlab. Then a comparison study was
investigated using the numerical simulation and Shercliff's weight function. It proved that the finite element
methodology is correct for solving the weight function. Based on this result, a new kind of weight quantity solution
scheme was carried out when the electrodes are located on the internal circumference of flow pipe and the connecting
line of electrodes is parallel to the pipe diameter that is superposition with the coordinate axis. This methodology is
effective to obtain the weight function value of electromagnetic flow meter and will be used in the invert reconstruction
of the velocity profile imaging, which is significantly important for volumetric flow rate measurement.
Dynamic characteristics of electrohydraulic servosystems exciting with square-like pressure wave
Author(s):
H. Chang;
C. W. Lana;
M. J. Kao;
L. C. Chenc;
H. Y. Yeh
Show Abstract
This paper uses the square-like wave produced by square pressure wave generator to excite the electrohydraulic servosystem and simulate the aeroservoelasticity, so as to evaluate the dynamic characteristics of electrohydraulic servosystem after exciting by high frequency square-like pressure waves. Such a simple hydraulic testing system can replace the resource-consuming wind tunnel test of aeroservoelasticity. In the system, a PID-controller is employed to give electrohydraulic servovalve a command via AD/DA interface card in order to drive the actuator. In the meantime, the square-like pressure wave of the different pressures and frequencies produced by square pressure wave generator would forcefully excited the actuator. Then linear variable differential transformer is used to measure the displacement of the actuator, ultimately achieving the feedback signal and positioning of the actuator. The results show that the electrohydraulic servosystem system is unstable and uncontrollable when the external static pressure approaches the pressure of electrohydraulic servosystem. Raising the frequency of the exciting can reduce the amplitude of the actuator at positioning. However, as the frequency of exciting is at a certain particular region, the amplitude will achieve the maximum value. During this time, the positioning of the actuator which is controlled by electrohydraulic servosystem becomes unstable. Apart from developing a new testing method of the dynamic characteristics of electrohydraulic servosystem, this paper makes an in-depth dynamic analysis of electrohydraulic servosystem.
The measurement of energy consumption by exercise bikes
Author(s):
Ching-Song Jwo;
Chao-Chun Chien;
Lung-Yue Jeng
Show Abstract
This paper is intended as an investigation is that to measure the amount of energy consumption can be consumed by riding bikes and also could recycle the consuming energy during exercising. Exercisers ride the bicycle inputting the driving force through a compressor of refrigeration system, which can circulate the refrigerant in the system and calculate the calorific capacity from the spread of the condenser. In addition, we can make up chiller water in the evaporator. Experiments were performed to prove the hypotheses. Therefore, this experiment has designed the sports goods which reach the purpose of doing exercise, measuring accurately the consuming calorific capacity and having the function of making chiller water. After exercising, you can drink the water producing during exercise and apply on the system of air conditioner, which attains two objectives.
Data modeling of the next generation GPS information system
Author(s):
Wenlong Lu;
Xiaojun Liu;
Xiangqian Jiang;
Zhengao Xu
Show Abstract
The next generation GPS (Geometrical Product Specification and Verification) is a very important basic technique standard system for manufacturing. It has been developing by ISO/TC 213 since 1996. But it is an intricate and abundant information system for engineering application and causes the problem of popularized usage. An integrated information system of the next generation GPS is proposed in this paper. For data modeling of next generation GPS information system, a new modeling method based on category theory is put forward and called GDM (Geometrical Data Model) in the paper. An important advantage of the method lies in its configurable semantics which can make the structure relationship clearly amongst the meta knowledge of standards issued or revised by the ISO/TC213, and by this method, features such as null values, uncertainty and temporal behavior can be added easily by selecting appropriate instance categories.
A new method based on WMRA and ANN for GPS/SINS integration for aerocraft navigation
Author(s):
Xuefen Zhu;
Xiyuan Chen;
Zigang Li
Show Abstract
Global Positioning System (GPS) can provide precise positioning information to an unlimited number of users anywhere on the earth. However, the defect cannot be neglected, because there exists one blind district when the aerocraft flying through some altitude space. During the short time in the blind district, all radio signals can't be attained including the GPS signals. An integrated GPS/SINS (Strapdown Inertial Navigation System) Navigation system is presented in this paper. The SINS based on numerical computing platform has many advantages such as high reliability, small bulk and low cost ect. The integration of GPS and SINS, therefore, provides a navigation system that has superior performance in comparison with either a GPS or a SINS stand-alone system. This paper presents a new model-less algorithm that can perform the self-following of the aerocraft under all conditions. For improving the precision of the hybrid GPS/SINS navigation system, fusing data from a SINS and GPS hardware utilizes wavelet multi-resolution analysis (WMRA) and Radial Basis Function (RBF) Artificial Neural Networks (ANN). The WMRA is used to compare the SINS and GPS position outputs at different resolution levels. These differences represent, in general, the SINS errors, which are used to correct for the SINS outputs during GPS outages. The RBF-ANN model is then trained to predict the SINS position errors in real time and provide accurate positioning of the moving aerocraft. The simulations show that good results in SINS/GPS positioning accuracy can be obtained by applying the WMRA and RBF-ANN methods.
Evaluation and management of measurement uncertainty in the new generation geometrical product specification (GPS)
Author(s):
Heping Peng;
Xiaojun Liu;
Xiangqian Jiang;
Zhengao Xu
Show Abstract
Because of measurement errors objectively existing, measurement results always deviate from the "true value" of the measurand. Measurement uncertainty, as a quality index characterizing measurement results, attracts more attention worldwide. Its evaluation and expression will help understand measurement results, and promote international technical and commercial communication. According to the International Organization for Standardization ISO/BIPM "Guide to the Expression of Uncertainty in Measurement" - usually referred to as the GUM, this paper deals with the way of evaluation and expression of measurement uncertainties, describes the Procedure for Uncertainty of Measurement MAnagement (PUMA) in the new generation Geometrical Product Specification (GPS). An example of uncertainty evaluation with the PUMA method is given to illustrate the validity of PUMA. Since the concept of uncertainty in the new generation GPS has been expanded beyond just measurement uncertainty, the new way of evaluation and management of uncertainty throughout the whole GPS system remains to be developed.
Research and development of network virtual instrument laboratory
Author(s):
Hongmei Cui;
Xichun Pei;
Hongyue Ma;
Shuoshi Ma
Show Abstract
A software platform of the network virtual instrument test laboratory has been developed to realize the network function of the test and signal analysis as well as the share of the hardware based on the data transmission theory and the study of the present technologies of the network virtual instrument. The whole design procedure was also presented in this paper. The main work of the research is as follows. 1. A suitable scheme of the test system with B/S mode and the virtual instrument laboratory with BSDA (Browser/Server/Database/Application) mode was determined. 2. The functions were classified and integrated by adopting the multilayer structure. The application for the virtual instruments running in the client terminal and the network management server managing the multiuser in the test laboratory according to the "Concurrent receival, sequential implementation" strategy in Java as well as the code of the test server application responding the client's requests of test and signal analysis in LabWindows/CVI were developed. As the extending part of network function of the original virtual test and analysis instruments, a software platform of network virtual instrument test laboratory was built as well. 3. The communication of the network data between Java and the LabWindows/CVI was realized. 4. The database was imported to store the data as well as the correlative information acquired by the server and help the network management server to manage the multiuser in the test laboratory. 5. A website embedding Java Applet of virtual instrument laboratory with the on-line help files was designed.
A new precise cubage measurement system for columned oilcan
Author(s):
Lixing Jiang;
Xuedong Jia;
Anjian Wang;
Chuanbo Wu
Show Abstract
In this paper, a new columned oilcan cubage precise measurement system that based on laser plumb line and photoelectric sensor ruler is introduced. In this system, laser plumb line is used instead of optical plumb line, and the photoelectric sensor ruler is used instead of mechanical ruler, and a digital terminal is used to record data from photoelectric sensor ruler lineless instead of reading and recording artificially. By using of this system, surveyor would do the jobs more comfortable and more efficiency in cubage measurement of columned oilcan.
Computer-vision-based inspecting system for needle roller bearing
Author(s):
Wei Li;
Tao He;
Fei Zhong;
Qinhua Wu;
Yuning Zhong;
Teiling Shi
Show Abstract
A Computer Vision based Inspecting System for Needle Roller Bearing (CVISNRB) is proposed in the paper. The characteristic of technology, main functions and principle of CVISNRB are also introduced. CVISNRB is composed of a mechanic transmission and an automatic feeding system, an imaging system, software arithmetic, an automatic selecting system of inspected bearing, a human-computer interaction, a pneumatic control system, an electric control system and so on. The computer vision technique is introduced in the inspecting system for needle roller bearing, which resolves the problem of the small needle roller bearing inspecting in bearing production business enterprise, raises the speed of the inspecting, and realizes the automatic untouched and on-line examination. The CVISNRB can effectively examine the loss of needle and give the accurate number. The accuracy can achieve 99.5%, and the examination speed can arrive 15 needle roller bearings each minute. The CVISNRB has none malfunction in the actual performance in the past half year, and can meet the actual need.
Development of a novel optical alignment system for accurate leveling adjustment of a high-precision chip mounter
Author(s):
Wenchao Liu;
Yuning Zhong;
Liangen Yang;
Xuanze Wang;
Tiebang Xie
Show Abstract
Automatic high-precision chip mounter have been applied frequently in high-precision and complex craft situations. The key to the equipment is the vision alignment system. The leveling adjustment is the important part and preconditin of the alignment. On the basis of a correlative leveling adjustment technlogy, a novel optical alignment system for leveling adjustment is presented. Its optical system is designed and its flow of image processing is discussed. To avoid the influence of interference, the polarization of the light is used skillfully in the optical system. The result of simulated experiments of the reticle-mark collected by a charge couple device (CCD) indicates that the system can meet the precision needs of an automatic chip mounter vision alignment system and it is reasonable.
A new collimation-checking system based on Newton's ring
Author(s):
Ren Wang;
Qing Xu;
Xinhui Zhu;
Peng Wang
Show Abstract
The near stalk interference of laser could result in the phenomena of Laser Newton's Ring which can be regarded as the linear basis of high precision, long distance collimation-checking because of its prominent merits such as steady facula, linear transmitting and so on. There will be a comprehensive application future of Laser Newton's Rings in such places as detecting of dam deformation, collimation-checking of the track and guidance of high precision in production lines. Here, a new collimation-checking system which is based on Laser Newton's Ring is implemented. Finally, an experiment is performed as well as an ideal result shown.
The kinetic property and application of the total station instrument
Author(s):
Yabo Luo;
Yong Zheng;
Zhiguo Xia;
Shaobo Wu;
Wenbai Zhu
Show Abstract
In the field of static surveying, the automatic Total Station Instrument is well known for its high precision of
sub-millimeter in range measure and sub arc-second in angular measure. It is also named "surveying robot" for that it
achieves the performance to be automatic and intelligent, such as the function of Automatic Target Recognition (ATR).
By now, the research of its application has been focused on the field of static surveying. However, in the field of kinetic
surveying its application also has a wide prospect because of its ATR function. In this paper, the results about our latest
systematic research and development of its kinetic surveying capability was presented for the first time, which includes
the following.
1) Testing and analysis of surveying lag and determination for the measuring moment. Achieving the function to time a
certain surveying event with an accuracy of milliseconds by developing a program and uploading it to the GSI operation
system which is embedded in the total station instrument. In order to test and analyse the surveying lag, the reflector
fixed on the platform of the mechanism (Stewart Platform) can move at the designed trace that is controlled by the
mechanism with enough precision. The trace can be measured and recorded by the mechanism and the automatic Total
Station Instrument in the same time. By the correlation analysis of the results measured by the Total Station Instrument
and the mechanism, the lag is about to 150 ms (the delay for the transmission was considered) and the uncertainty is
about 2 mm.
2) The discussion about the sampling rate and surveying lag for a kinetic measurement was proposed at first, and the
quantitative results were presented.
3) The development of the automatic kinetic surveying system based on the automatic Total Station Instrument which
was used in kinetic surveying on a feed-supporting system of a 50 meter-model of the FAST project, in this application,
the position uncertainty is less than 2 mm and the sampling rate is higher than 5 Hz. It shows that using of the automatic
Total Station Instrument for contactless kinetic surveying on large scale has an advantage especially in the aspect of
tracking velocity, range for measurement, sampling rate and position precision.
Three-dimensional all-around shape measurement system based on image processing
Author(s):
Xiaohua Ni
Show Abstract
An automatic all-around three-dimensional shape measurement system is introduced. Striped patterns from an optical modulator are projected on the surface of the object. By rotating the precision work-table, the deformed patterns were recorded by a CCD camera from different angles and stored in a computer, and the 3D coordinates of the surface of the object were calculated according to geometric relations. Thus from an arbitrary direction, 2D views and 3D solid models of the measured object may be constructed conveniently. After a series of image processing, the sizes of object may be measured. With this system, it is possible to capture the surface topography far away from the object. The error influence factors of the system and image processing are analyzed. Experiments show the measurement process and the effect of the measurement.
Principle of reflecting measurement system for roller wear and software simulation
Author(s):
Longjiang Zheng;
Kai Wang;
Yuan Guo;
Yutian Wang
Show Abstract
Roller plays an important role in rolling mill. However, the effective surface of roller is limited. After long time working, the surface of roller will wear. The roller wear will result in difficult controlling of shape and thickness of steel board. Further more, it can lead to the decline of product quality. So the measurement of roller wear is very urgent for rolling mill to ensure their product quality. In this paper, a measurement method for roller wear is introduced in detail. This method offers advantages of sensitivity, immediate response, electromagnetic interference, simplicity and non-contact. It can detect in the atrocious condition on-line and examine roller wear precisely and real time. It is an effective method at low cost instance. The basic principle of this system is optical reflection principle. In the paper, after explaining the principle of this measurement system, an error compensation algorithm is exactly calculated to improve accuracy of this measurement system. This algorithm is brought out to offset the shift of measurement track. And a simulation-software program is compiled with Microsoft Visual Basic 6.0 based on this principle. By using this simulation-software, the date of I/O signal for this system is gained. And the signal verse is automatically drawn in this software.
The design of the video theodolite and its application
Author(s):
Lixing Jiang;
Ren Wang;
Bing Tan
Show Abstract
In this paper, a new video theodolite composed of high resolution digital camera, theodolite and antenna of GPS is designed, with which the elements of exterior orientation of camera and the length of base can be gained accurately. The way to calibrate the instrument is also researched. Finally, its application to digital close-range photogrammetry is introduced.
An astronomical azimuth measurement system aided with an automatic gyro total station
Author(s):
Zhiguo Xia;
Chao Zhang;
Yong Zheng;
Lixing Jiang
Show Abstract
Gyro orientation technique is widely used in many fields, such as navigation, aviation, space probe and engineering
construction. It is one of the key techniques in subterranean construction.
In this paper, the advantages and disadvantages of the orientation methods such as GPS orientation, gyro-orientation and
astronomical orientation are discussed. The astronomical azimuth measurement system that is aided by an automatic
gyro station is introduced. This system is composed of an automatic target recognition station, a gyro orientation device,
a GPS receiver and a portable computer. By used of the system, surveyors could survey the astronomical azimuth at any
time and in any field accurately whether on ground or underground. Test show that the measurement precision could
meet the demand of fist order for the astronomical azimuth. Other gyro-theodolites could be compared with this system,
and thus be corrected.
The automatic target recognition station is the key instrument in the system and the automatic target recognition
technique (ATR) is taking an important role in the precise orientation measurement. We made a test to analyze the
aiming errors difference between a long distance and a short distance target by the ATR and precise manual aiming. The
result shows that there are some differences for different distances by the ATR. When using the gyro station for an
orientation we should choose different observation method.
Development on a dynamic pressure test system of internal combustion engines
Author(s):
Dongmei Yuan;
Xihong Zou;
Yun Xu
Show Abstract
The performance of a piston internal-combustion engines is reflected by indicator diagram and indicator parameters. It is of great significance to evaluate performance, inspect quality, redesign and maintain internal-combustion engine by computing parameter and analyzing combustion according to tested indicator diagram. Aimed at two-stroke piston engines, a dynamic pressure test system of internal-combustion engines is developed with high speed acquisition devices, angle signal generators and pulse shapers. After a further research on the measurement of dynamic top dead center (TDC), the computer algorithm based on the p-ψ indicator diagram of TDC and the average indicator pressure is putted forward. With the application of the multithreading technique, dynamic link library technique and multi-document template technique, a testing software, which is credible and multi-purpose, is programmed. The experiment indicates that the indicator diagram and indicator parameters can be under accurate measurement with the testing system.
A machine vision system for micro-EDM based on linux
Author(s):
Rui Guo;
Wansheng Zhao;
Gang Li;
Zhiyong Li;
Yong Zhang
Show Abstract
Due to the high precision and good surface quality that it can give, Electrical Discharge Machining (EDM) is potentially an important process for the fabrication of micro-tools and micro-components. However, a number of issues remain unsolved before micro-EDM becomes a reliable process with repeatable results. To deal with the difficulties in micro electrodes on-line fabrication and tool wear compensation, a micro-EDM machine vision system is developed with a Charge Coupled Device (CCD) camera, with an optical resolution of 1.61μm and an overall magnification of 113~729. Based on the Linux operating system, an image capturing program is developed with the V4L2 API, and an image processing program is exploited by using OpenCV. The contour of micro electrodes can be extracted by means of the Canny edge detector. Through the system calibration, the micro electrodes diameter can be measured on-line. Experiments have been carried out to prove its performance, and the reasons of measurement error are also analyzed.
Dynamic characteristics and testing techniques of microstructures under high load
Author(s):
Xiaodong Wang;
Tao Wang;
Liding Wang;
Dong Yin;
Nan Li
Show Abstract
To study the dynamic characteristics of micro inertial components under high load, dynamical equation including the effect of dead load (constant acceleration) is discussed based on Hamilton's principle. The effects of acceleration on the natural frequency of a typical micro inertial component, i.e. the beam-proof mass structure, are analyzed with finite element method. The natural frequency of microstructure was calculated with different high g-force accelerations and beam length. The results show the natural frequency of microstructure gets higher as the inertial force increases because the structural stiffness is strengthened by the load-induced stiffness. A dynamic testing experimental instrument was developed, and experiment was carried out with the instrument. The instrument can generate high g-force environment, impose impact on microstructure and measure the corresponding response. The experimental results show that the resonant frequency of microstructure gets higher as the environmental acceleration increases, and that is consistent with theoretical analysis. The study has practical value for design and fabrication of high g-force micro-inertial components.
Volumetric effects on the dynamic pressure wave in hydraulic system
Author(s):
Tsing-Tshih Tsung;
Sheng-Hung Wang;
Lee-long Han;
Kae-Yuan Cheng
Show Abstract
The dynamic characteristics of hydraulic system were commonly analyzed by the time domain response. The rise time and maximum overshoot are both significant specifications for presenting the dynamic chrematistics. A dynamic pressure generator, was called pressure square wave generator (PSWG), was used as an input source for exciting the response of hydraulic devices. The testing frequency and amplitude of PSWG was arbitrary and the testing range was employed between 16 and 300 Hz. The primary objective of this paper was investigating the volumetric effects on PSWG. The volume was the chamber of a hydraulic cylinder and changed by controlling the stroke in 50 mm incensement between 0 mm to 200 mm. Results show that the greater the chamber volume obtained the larger the rise time, smaller the maximum overshoot and the waveform tended to trapezoid-like shape.
A new contrastive method for measuring surface tension of the human cornea in vivo
Author(s):
Jianguo Ma;
Xueyong Zhang
Show Abstract
A new contrastive method to measure the surface tension of the human cornea in vivo is introduced. Analyzing pressure-volume relationships and conditions of force equilibriums during the indention and applanation tonometry, the relationship of the intraocular pressure value and the change of the intraocular volume measured in the applanation tonometry as a function of the difference in the intraocular pressure between the indention and applanation tonometer readings, which was derived, the coefficient of surface tension for the human cornea was further obtained using this relationship and the difference also relative to the coefficient was considered to be the contribution of the surface tension of the human cornea. Laboratory experiments were carried out on a stimulated eyeball connected to a hydraulic manometer to accomplish the intraocular pressure at different levels. The stimulated eyeball at a chosen intraocular pressure level was measured with Schiotz indention tonometry, followed, according to the same change of intraocular volume, by Ma applanation tonometry. Preliminary experimental results showed the coefficient of the surface tension for the cornea agreed with the value calculated. This contrastive method may therefore be used to determine the coefficient of the surface tension for the human cornea and to estimate the surface tension of the human cornea in vivo. Further study including clinical trials and application is required to evaluate the usefulness and accuracy of this method.
A new method for measuring elastic constants of limited-size materials and the errors analysis
Author(s):
Guorong Song;
Xiaoling Wei;
Cunfu He;
Bin Wu
Show Abstract
A new method of measuring elastic constants of limited-size materials is presented in this paper. The measurement is based on acoustic microscope technology. The material elastic constants are determined by measuring longitudinal wave and leak surface wave velocity simultaneously by the system with a line-focus PVDF transducer developed by ourselves. Based on the virtual instrument technology, a set of precise measure software was programmed. Experimental tests on three limited-size samples, aluminum, cuprum and steel, were carried out using the line-focus PVDF transducers and automatically measure software. The experimental results indicate that the ultrasonic measurement system can be used to determine the elastic constants of limited-size materials accurately. The main factors to affect the precision of elastic constants were discussed, including the measuring error of defocus distance, thickness and time interval. Take Young's modulus of aluminum for an example, the qualitative analysis of the errors sources influence on the measure system was made. This method is suitable not only to measuring elastic constants of isotropy materials, but also those of anisotropic ones.
Thermal vision measurement based on mapping transform
Author(s):
Yongyue Yang;
Shanxi Deng
Show Abstract
An active vision detection technology based on laser target is proposed in this paper for measuring the dimensions of thermal train wheels in workshop. A mapping transorm of histogram is used to restrain thermal background and extrude the laser target, therefore, it is necessary to search the transform threshold value. The color weights of the image background are analysed. A contrast of the laser targe stripe and a recognized error are pursued to a best threshold for image mapping transform. The experiments prove that the useful information of the laser target image is extruded and the recognized errors caused by the mapping transorm are less than 0.04 pixel. A theoretical foundation is set up for the laser target pick-up correctly and other image processing expediently.
Noncontact infrared temperature measurement using machine vision
Author(s):
Fei Zhong;
Tielin Shi;
Tao He;
Yuning Zhong
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Temperature monitoring is a common requirement; the thermocouples can accurately control the temperature of rotating and moving heated object, without touching it. Uncoated metal heaters are difficult for infrared sensors to measure reliably, the reflected infrared signals can change after a heated object surface is clean, the smog is rareness after the clean heated object has been burnt, when the surface is dirty and smeary, the smog is so dense that the measurement result would be influenced. In order to measuring the metal heater accurately, the measurement noise can be reduced by the machine vision. The Self-Organizing Maps (SOM) is an efficient tool for image processing. It projects input space on prototypes of a low-dimensional regular grid. In this paper a new image process technique has been validated against U-matrix method based on Euclidean distances between input vectors and neurons weights combined with the distribution of the fixed lattices in the network. SOM, as an unsupervised neural networks, is applied to pattern recognition and image processing. By analyzing and processing of the noise signals of the image, the characteristic parameters which represent operating state of the heated object are extracted to construct characteristic vector and used to train SOM. The trained results can be used to modify the sensor testing value. A new image processing scheme based on the use of the organization property of Kohonen maps are presented in this paper, the image processing result can be correct the non-contact infrared temperature measurement.
ER fluid and its application in cutting chatter control
Author(s):
Conggui Chen;
Chunliang Zhang;
Haibo Lv;
Yongtao Jiang
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ER fluid is an agile material, its viscosity and yield stress can be changed when exposed to an electric field. This feature provides simple, quiet, rapid response interfaces between electronic controls and mechanical systems. ER fluid dampers are relatively new semi-actives that utilize ER fluids to provide controllable damping forces. In this paper, following the introduction of the essential characteristics of ER fluids and ER fluid dampers, the theoretical model is presented to describe the ER fluid. A damper based on a shear model is designed to control a cutting chatter. The excitation test and cutting test are carried out to verify the damper's performance. The response of the ER fluid damper under different conditions is obtained. The results of the test show that ER fluid can well control the vibration and chatter.
Real-time running workpiece temperature measurement at room temperature with refrigeration reference
Author(s):
Kebao Xu;
Xiaojun Ju;
Ping Zhu;
Juncheng Wang
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Non-contact is the only way used in real-time measurement of object surface temperature at dynamic state. Pyroelectric crystal material is heat-variable detector that is sensitive to temperature difference, but when temperature of detected object is close to or equal to that of ambient temperature, noise coefficient of using pyroelectric crystal material to measure difference is very prominent, so measurement accuracy can be reduced or measurement meaning is lost. This paper puts forward temperature difference compare method using precise refrigeration temperature as reference. Measurement of detected temperature at normal temperature using this method can not only overcome low SNR (Signal Noise Ratio) problem caused by small measurement temperature difference, but also compensate measurement error caused by ambient temperature changes. Based on measuring temperature characteristics of pyroelectric material, it is generally required that high SNR can be acquired only when temperature difference between refrigeration reference temperature and detected object temperature is more than 3°C.
A novel vibration structure for dynamic balancing measurement
Author(s):
Peng Qin;
Ping Cai;
Qinghan Hu;
Yingxia Li
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Based on the conception of instantaneous motion center in theoretical mechanics, the paper presents a novel virtual
vibration structure for dynamic balancing measurement with high precision. The structural features and the unbalancing
response characteristics of this vibration structure are analyzed in depth. The relation between the real measuring system
and the virtual one is emphatically expounded. Theoretical analysis indicates that the flexibly hinged integrative plate
spring sets holds fixed vibration center, with the result that this vibration system has the most excellent effect of plane
separation. In addition, the sensors are mounted on the same longitudinal section. Thus the influence of phase error on
the primary unbalance reduction ratio is eliminated. Furthermore, the performance changes in sensors caused by
environmental factor have less influence on the accuracy of the measurement. The result for this system is more accurate
measurement with lower requirement for a second correction run.
Magnetic field calculation and measurement of active magnetic bearings
Author(s):
Guoping Ding;
Zude Zhou;
Yefa Hu
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Magnetic Bearings are typical devices in which electric energy and mechanical energy convert mutually. Magnetic Field indicates the relationship between 2 of the most important parameters in a magnetic bearing - current and force. This paper presents calculation and measurement of the magnetic field distribution of a self-designed magnetic bearing. Firstly, the static Maxwell's equations of the magnetic bearing are presented and a Finite Element Analysis (FEA) is found to solve the equations and get post-process results by means of ANSYS software. Secondly, to confirm the calculation results a Lakeshore460 3-channel Gaussmeter is used to measure the magnetic flux density of the magnetic bearing in X, Y, Z directions accurately. According to the measurement data the author constructs a 3D magnetic field distribution digital model by means of MATLAB software. Thirdly, the calculation results and the measurement data are compared and analyzed; the comparing result indicates that the calculation results are consistent with the measurement data in allowable dimension variation, which means that the FEA calculation method of the magnetic bearing has high precision. Finally, it is concluded that the magnetic field calculation and measurement can accurately reflect the real magnetic distribution in the magnetic bearing and the result can guide the design and analysis of the magnetic bearing effectively.
A method of laser-induced microscopic torque measurement
Author(s):
Yonghong Liu;
Jinshan Shi;
Yuyan Zhang
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It has been established that under certain conditions a tightly focused laser beam can trap microscopic particles in the size range from tens of nanometers to tens of micrometers. This technique is commonly referred to as optical tweezers and is widely used in many biological applications. The optical forces and torques applied by the trapping beam to the particle result from the transfer of momentum and angular momentum from the trapping beam to the particle. In recent years there has been an explosive development of interest in the measurement of forces and torques at the microscopic level, such as within living cells, as well as of the properties of fluids and suspensions on this scale, using optically trapped particles as probes. Here we present a novel method for a simple, accurate, simultaneous measurement of the rotation speed of an optical trapped birefringent particle, and the optical torque acting on it, by measuring the change in angular momentum of the light from passing through the particle. This method does not depend on the size or shape of the particle or the laser beam geometry, nor does it depend on the properties of the surrounding medium, and provides a mean to accurately measure the viscosity of interest on a microscopic scale.
Computer simulation and model test research on strength test of hydraulic support
Author(s):
Hongyu Liu;
Xun Fan
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This paper took ZT6500/19.5/34 hydraulic support as an example, made a solid model construction on its prototype and 1 to 5 model by SolidWorks software, proceeded a computer simulation analysis on simplified support prototype and its model with the status of concentration load on central section of support top beam by ANSYS software, drew relevant total displacement figure and equivalent stress figure, found out relevant distribution rule. Based on the similarity theory, static similarity rule and static similarity condition of hydraulic support model test were constructed, hydraulic support model test board and its hydraulic control system, data collecting and processing system were constructed. According to the national standard, strength test was made on support model with the status of concentration load on central section of support top beam. The research shows that computer simulation results are consistent with actual model test results, which verifies the accuracy of computer simulation results. The method of combining computer simulation test with hydraulic support model test has the advantage of less test cost, short exploitation period, accurate and comprehensive analysis, which enhances the level of entire design, calculation and test and provides an effective way of systematically theoretical and experimental study on hydraulic support.
A high precision weight measurement system based on chaotic theory
Author(s):
Liuqing Du;
Wenjie Feng;
Yudan Zeng
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Aimed at the traditional weight measurement system's shortcomings of bad stability, low precision and complicated circuit, a high precision based on chaotic circuit is put forward. One of its outstanding characteristics is to make use of the high sensitivity to initial values of chaotic system and apply chaotic theory to weight measurement. Besides, through adopting a voltage controlled by constant-current sourced to produce charge current or discharge current, linearity and stability of the measurement system is increased. In addition, the system has great adaptability and simple circuit. The theoretic error range of this system is less than ±0.1μg, and the theoretic resolution is 0.01μg, which are verified approximately by experimental statistics.
Numerical study on cold transfer characteristics of the space in a semiconductor refrigeration device
Author(s):
Hui Zhang;
Jun Wang;
Kuang-Chao Fan
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This paper presented the variation law of temperature in three-dimensional space, which is cooled by the refrigeration provided by the cold side of a semiconductor. It's tested under the conditions of the natural and forced convection in a semiconductor refrigeration device under steady working conditions. The mathematical model of the temperature field of the semiconductor refrigeration device is described, and a numerical study on the temperature profile in a semiconductor refrigeration device was carried out using this model. Numerical simulation is applied to the present thermostated container. Then the space tempo direction in the case of the gas flows, distribution of pressure in each point, the data of three-dimensional temperature field, etc. are gained. The problems in present thermostated containers are discussed, the factor influencing current air organization and temperature field are analyzed. The experimental results show that forced convection is of benefit to the cold transfer and to the rise of refrigeration rate.