Implementation and performance results of wavelet network for analysis of fault signal in power system
Author(s):
Weili Huang;
Wei Du
Show Abstract
A new method is proposed to detect fault signal in power system using wavelet transform and neural network. The
wavelet transform can decompose the original signal into several other signals with different levels of resolution. From
these decomposed signals, the original time-domain signal can be recovered without losing any information. In order to
increase the signal-noise-ratio, statistic rule is used to determine the wavelet decomposition level and threshold.
Considering the inter relationship of wavelet decomposition coefficients, the signal features obtained from wavelet
transform are presented for fault pattern classification. According to threshold value of each type of fault signal in each
frequency band, the correlation between the type of signal and the signal features can be figured to fault pattern
classification. As to this model, the advantages of morphological filter and wavelet transform are used to extract the fault
feature meanwhile restraining various noises. The simulation results demonstrate that the proposed approach is verified
to be effective.
Dynamic time-frequency analysis method for transient signal in power system network
Author(s):
Baoqun Zhao;
Yuanyang Wang
Show Abstract
To improve the performance of power quality (PQ) disturbances classification, a novel approach using wavelet neural
network is proposed. The wavelet transform can accurately localizes signal characteristics in time-frequency domains
The wavelet transform is utilized to extract feature vectors of different PQ disturbances. These feature vectors then are
applied to the neural network for training and disturbance pattern classification. By comparing with classic neural
network, it is concluded that the proposed neural network has better data driven learning and local interconnections
performance. The research results between the proposed method and the other existing method are discussed and the
proposed method can provide accurate classification results. The simulation results demonstrate the proposed method
gives a new way for identification and classification of power quality disturbances.
Qualitative fusion technique based on information poor system and its application to factor analysis for vibration of rolling bearings
Author(s):
Xintao Xia;
Zhongyu Wang
Show Abstract
Poor information means incomplete and insufficient information for the characteristic presented in the subject
investigated. The qualitative fusion technique is proposed by this paper to solve some problems of statistics under the
condition of poor information. Based on the grey system theory which allows the probability distribution unknown and
the data number small, the concept, qualitative fusion, is defined and its calculating method is described via factor
analysis of the influence on the performances of rolling bearings. Experiments on factor analysis for vibration of the
tapered roller bearing show that the main factors of the influence on vibration of the tapered roller bearing are linearity of
the outer ring raceway, squareness of the bore surface, waviness of the outer ring raceway, roundness of the inner ring
raceway, and roughness of the inner ring raceway. Hereby vibration of the tapered roller bearing can be improved by
means of controlling over these 5 quality indexes of the rolling bearing rings.
Analysis for systematic stability using fuzzy-set theory
Author(s):
Xintao Xia;
Zhongyu Wang
Show Abstract
For some methods of stability analysis of a system using statistics, it is difficult to resolve the problems of unknown
probability distribution and small sample. Therefore, a novel method is proposed in this paper to resolve these problems.
This method is independent of probability distribution, and is useful for small sample systems. After rearrangement of
the original data series, the order difference and two polynomial membership functions are introduced to estimate the
true value, the lower bound and the supper bound of the system using fuzzy-set theory. Then empirical distribution
function is investigated to ensure confidence level above 95%, and the degree of similarity is presented to evaluate
stability of the system. Cases of computer simulation investigate stable systems with various probability distribution,
unstable systems with linear systematic errors and periodic systematic errors and some mixed systems. The method of
analysis for systematic stability is approved.
Processing on weak electric signals by the autoregressive model
Author(s):
Jinli Ding;
Jiayin Zhao;
Lanzhou Wang;
Qiao Li
Show Abstract
A model of the autoregressive model of weak electric signals in two plants was set up for the first time. The result of the
AR model to forecast 10 values of the weak electric signals is well. It will construct a standard set of the AR model
coefficient of the plant electric signal and the environmental factor, and can be used as the preferences for the intelligent
autocontrol system based on the adaptive characteristic of plants to achieve the energy saving on agricultural
productions.
Sampling uncertainty evaluation for data acquisition board based on Monte Carlo method
Author(s):
Leyi Ge;
Zhongyu Wang
Show Abstract
Evaluating the data acquisition board sampling uncertainty is a difficult problem in the field of signal sampling. This
paper analyzes the sources of dada acquisition board sampling uncertainty in the first, then introduces a simulation
theory of dada acquisition board sampling uncertainty evaluation based on Monte Carlo method and puts forward a
relation model of sampling uncertainty results, sampling numbers and simulation times. In the case of different sample
numbers and different signal scopes, the author establishes a random sampling uncertainty evaluation program of a
PCI-6024E data acquisition board to execute the simulation. The results of the proposed Monte Carlo simulation method
are in a good agreement with the GUM ones, and the validities of Monte Carlo method are represented.
A novel precision machine design method based on CAXA and ANSYS
Author(s):
Wei Shi;
Leyi Ge;
Qian Wang
Show Abstract
In order to design a high precision machine, because of considering disadvantages of traditional design methods, the
authors use novel professional design software CAXA to carry out Three-Dimensional solid modeling for a precision
machine, and then through the interface between CAXA and ANSYS, import the model into ANSYS which is a large
scale general finite element analysis software with abroad application, perform Finite Element Analysis and
Optimization Design in use of ANSYS for some main precision mechanical structures. This design can make up for the
disadvantage of ANSYS on modeling, short the machine design period, improve the accuracy, make some change
according to the need. Finally, according to design a special high precision Brinell Hardness Tester, the authors
demonstrate this novel precision machine design method successfully. This novel is good enough to be used as a
reference when engineering technicians perform the mechanical modernized designing.
The fractal characteristic of vibration signals in different milling tool wear periods
Author(s):
Chuangwen Xu;
Hualing Cheng;
Limei Liu
Show Abstract
There are a wide variety of condition monitoring techniques currently used for the recognition and diagnosis of
machinery faults. Tool wear often results in chaotics on milling process. Little research has been carried out about the
occurrence and detection of chaotic behavior in time series signal of tool vibration. In the paper the vibration
acceleration signal based on the operating stages of tool wear is established for the analysis of the correlation dimension
of the operating stages of tool wear. Correlation dimension is calculated to recognize the tool wear operating conditions.
Finally ,some experimental results from the fractal characteristic show that there are distinct differences in the
correlation dimension in different tool wear conditions and close the correlation dimension in same tool wear conditions.
The correlation dimension not only can be used as important scientific basis for monitoring tool wear, but also
complement of other characteristic picking up method.
Maximum entropy bootstrap method for parameter estimation
Author(s):
Lin Zhang;
Xintao Xia;
Zhongyu Wang
Show Abstract
The maximum entropy bootstrap method is proposed to resolve the problem about parameter estimation under the
condition that the number of test times is small while every time the number of test data is much, in test analysis for
stochastic processes with unknown probability distribution. First the maximum entropy distribution of each test data is
established, then information about the maximum entropy distributions of all tests is fused by bootstrap resampling, and
lastly the inference of attribute of population is drawn from identifying the parameters of every individual, describing the
stable state of population. Simulation experiment shows that the estimated results using the maximum entropy bootstrap
method are coincident with the real truth of the subject investigated, with the relative errors of 0.14%~2.39% and the
better results by a 9%~20% decrease of the relative errors as compared with the maximum entropy method and the
bootstrap method.
Performance of wavelet analysis and neural network for detection and diagnosis of rotating machine fault
Author(s):
Shanlin Kang;
Yuzhe Kang;
Jingwei Chen
Show Abstract
A novel approach combining wavelet transform with neural network is proposed for vibration fault diagnosis of turbo-generator
set in power system. The multi-resolution analysis technology is used to acquire the feature vectors which are
applied to train and test the neural network. Feature extraction involves preliminary processing of measurements to
obtain suitable parameters which reveal weather an interesting pattern is emerging. The feature extraction technique is
needed for preliminary processing of recorded time-series vibrations over a long period of time to obtain suitable
parameters. The neural network parameters are determined by means of the recursive orthogonal least squares algorithm.
In network training procedure, much simulation and practical samples are utilized to verify and test the network
performance. And according to the output result, the fault pattern can be recognized. The actual applications show that
the method is effective for detection and diagnosis of rotating machine fault and the experiment result is correct.
Fault-tolerant control for a class of nonlinear dynamic systems
Author(s):
Ling-Ya Meng;
Bin Jiang
Show Abstract
In this paper fault-tolerant control is investigated for a class of nonlinear systems with model errors or external
disturbance. Firstly a fault diagnosis method is proposed to estimate the faults based on the adaptive state observer. Then
a novel fault-tolerant control scheme is designed to stabilize the nonlinear systems via the feedback linearization
technique. The main advantage of the approach is that it is easy to implement and in most cases it can place the poles of
the closed-loop systems arbitrarily. The effectiveness of the proposed scheme is demonstrated through the numerical
simulation.
General inference algorithm of Bayesian networks based on clique tree
Author(s):
Haijun Li;
Xiao Liu
Show Abstract
A general inference algorithm which based on exact algorithm of clique tree and importance sampling principle was put
forward this article. It applied advantages of two algorithms, made information transfer from one clique to another, but
don't calculate exact interim result. It calculated and dealt with the information using approximate algorithm, calculated
the information from one clique to another using current potential. Because this algorithm was an iterative course of
improvement, this continuous ran could increases potential of each clique, and produced much more exact information.
Hybrid Bayesian Networks inference algorithm based on general softmax function could deal whit any function for CPD,
and could be applicable for any models. Simulation test proved that the effect of classification was fine.
Fault detection and analysis of electric generator based on wavelet transform and fuzzy logic technology
Author(s):
Guangbin Ding;
Peilin Pang
Show Abstract
A new method combining wavelet transform with fuzzy theory is proposed to improve the limitation of traditional fault
diagnosis technology of electric generator. In order to determine the threshold of each order of wavelet space and the
decomposition level adaptively, the statistic rule is brought forward to increase the signal-noise-ratio. The wavelet
transform is used to acquire the effective feature components and the proposed fuzzy diagnosis equation is used to
complete classify fault pattern. The fault diagnosis model of electric generator is established and the network parameters
training are fulfilled by the improved least squares algorithm. The input nodes include the information representing the
fault characters. On basis of experiments data to train the fault diagnosis mode, the accurate classification results can be
achieved in accordance with expert experience. In view of actual applications, the proposed method can effectively
diagnose the fault pattern of electric generator.
Phase calibration for synthetic aperture imaging
Author(s):
Changwei Wang;
Yuesong Jiang;
Yuntao He;
Li Liu
Show Abstract
High-resolution imaging can be achieved by optical aperture synthesis. Using a sparse array of smaller aperture, one can
synthesize an aperture with the resolution of the equivalent filled aperture while reducing the size and weight of system.
The environment and vibration factors of synthetic aperture arrays lead to errors in phase measurement and cause a
severe degradation in the image quality. Real time phase calibration of synthetic aperture arrays is very important to
produce images of consistently good quality. Redundant spacings calibration allows continuous calibration of the
instrument with errors without requiring the model of the source.
Precision loss diagnosis about dynamic measurement system
Author(s):
Min-lan Jiang;
Jian-Guo Shen
Show Abstract
The law of precision loss about dynamic measurement system is studied in this paper. Its total loss accuracy can be
obtained by transformation law of its errors in different measuring phases of a certain measuring period. Based on the
total precision loss and its structural characteristic, WNN is used to decompose systemic total precision loss and trace to
its inside structural units, and build precision loss function model of structural units. So precision loss disciplinarian with
all units and infection of different unit to total precision loss is definitude, the principal infection unit to systemic total
precision can be distinguished. In the end of the paper an application examples have been introduced.
An obstacle avoidance of formation method for UAVs
Author(s):
Wei Zhou;
Rui-Xuan Wei;
Ying-Jie Wang;
Zhi-Xing Dong
Show Abstract
For the flight formation problem under the danger mode, a method based on the control architecture and decomposition
strategy for obstacle avoidance of formation is proposed. Constructing and searching a Voronoi diagram, the reference
flight paths for choice are generated based on K shortest path algorithm, then the cooperative function is established, the
collision avoidance path is designed for each UAV, which meets both the request of cooperative time and optimal (or
second optimal) cost of the whole formation.
Calculation of center of mass and inertia moment of human body in motion by means of transformation matrix
Author(s):
Yifang Fan;
Zhiyu Li;
Changsheng Lv
Show Abstract
Aim of research: Human body segment inertial parameters are the basic physical quantities in the study of human body
in motion. Through careful calculation, inertial parameters such as the position of center of mass and moment of inertia
of the total and segmental human body in motion in random postures have been obtained. Research method: Based upon
the basic inertial parameters derived from Hanavan human body model and from Barter regression equation, upon
position vector, moment and moment of inertia of the human body and segment relative to inertial reference frame by
means of transformation matrix, and upon the resultant moment theorem and the parallel-axis theorem, inertial
parameters such as the position of center of mass and moment of inertia of human body in random posture in motion are
thus obtained. Result and conclusion: The research findings are in accordance with those of the balance plate and
trilinear pendulum. The characteristics of individual and random posture of human body inertial parameter in motion are
presented in this paper.
Objective research and application of multi-channel human meridian impedance dynamic testing system
Author(s):
Bo Li;
Jun Zhang;
Jianling Jiao
Show Abstract
This paper is an in-depth study on the basis of the passed summary of relevant technologies. Multi-channel ring electrode
has been developed to point impedance testing of the human body for the first time. Here, we build such a system, which
bases on the hardware platform of AT89C52 combined with M82C54-2, besides, the integrated software development
tools micro-soft visual c++ and the technical advantages such as multi-threading, databases, serial communication and
the characteristics of real-time supported by Windows XP are used in here too. Except for the point impedance testing of
the human body, the conductive volume of the human meridian and infrared-photoelectric absorption properties of
physical quantities can also be detected by such an on-site data acquisition, analysis, display, record and communicate
with the PC portable System. Currently, the system was being in the testing phase, we have collected some real data of
human body with this vehicle, whose results are expected to be more satisfactory in the near future.
A new method for fault feature extraction of analog circuit
Author(s):
Qingjian Hou;
Hongli Wang
Show Abstract
The feature extraction is one of key steps in fault diagnosis. A method of least square support vector machine (LSSVM)
is put forward based on genetic optimization to restrain the end effect of empirical mode decomposition (EMD). Based
on the method, a method of feature extraction is put forward. The energy of intrinsic mode functions (IMF) generated
from EMD is to be the feature to distinguishing faults. The result of feature extraction experiment of analog circuit
shows that the method is effective.
Wavelet-based approach for detection and analysis of transient signal in distributed power system
Author(s):
Wei Liao;
Pu Han
Show Abstract
By combining wavelet transform (WT) with neural network theory, a novel approach is put forward to detect transient
fault and analyze voltage stability. The application of signal denoising based on the statistic rule is proposed to determine
the threshold of each order of wavelet space. In a view of the inter relationship of wavelet transform and neural network,
the whole and local fractal exponents obtained from WT coefficients as features are presented for extracting signal
features. The effectiveness of the new algorithm used to extract the characteristic signal is described, which can be
realized by the value of those types of transient signal. This model incorporates the advantages of morphological filter
and multi-scale WT to extract the feature of fault signal meanwhile restraining various noises. Besides, it can be
implemented in real time using the available hardware. The effectiveness of this model was verified with the voltage
stability analysis of simulation results.
Stability analysis of adaptive switching control scheme based on local overlapped switched systems
Author(s):
Yanze Hou;
Qing Wang;
Chaoyang Dong
Show Abstract
For a model reference adaptive switching control scheme, we proposed a novel concept local overlapped switched
system in this paper. Afterwards, we partitioned the closed-loop switched system, which is constructed upon reference
switched system and nonlinear adaptive control law set, into finite local overlapped switched systems. This disposal is
helpful to obtain a less conservative sufficient condition for global uniformly stability of the closed-loop switched
system. Finally, based on local overlapped switched systems, we deduced a sufficient condition for uniformly
boundedness of the closed-loop switched system which is essentially a nonlinear switched system.
Error separation technique for double flank gear testing
Author(s):
Lifeng Guo;
Ken Chen;
Xusheng Zhai
Show Abstract
The application of error separation techniques to double flank gear testing is investigated theoretically and
experimentally. The mathematic model for error separation is established with the theory of Fourier series. The limitation
of two-gear error separation method based on multi-step error separation technique is indicated. It can only separate the
total radial composite error, but do nothing with the tooth-to-tooth radial composite error. The accuracy of a three-gear
error separation method is also explored. In comparison with the two-gear error separation method, the three-gear
method can separate both the total and tooth-to-tooth errors. The theoretical error caused by gear's particular structure is
discussed. Experimental results show that the mathematic model is correct and the three-gear error separation method
performs better than the two-gear's.
Marker based watershed to segment dim infrared target through image enhancement
Author(s):
Fugen Zhou;
Xiangzhi Bai;
Yongchun Xie;
Ting Jin
Show Abstract
A novel marker based watershed through image enhancement is proposed to segment the dim infrared target. The dim
infrared target is firstly enhanced by CB top-hat transformation and image quantization. Then, the accurate marker of the
target can be easily obtained through image binarisation and marker filtering. To calculate an efficient gradient image of
the dim target for the watershed segmentation, the gradient image is firstly calculated through Sobel operator and then
efficiently enhanced through pseudo top-hat transformation and gradient quantization. Because of the enhancement of
the dim target and the gradient image, the watershed can efficiently segment the dim infrared image. Experimental
results show that the proposed algorithm is much efficient for dim infrared target segmentation.
Application of round grating angle measurement composite error amendment in the online measurement accuracy improvement of large diameter
Author(s):
Biao Wang;
Xiaofen Yu;
Qinzhao Li;
Yu Zheng
Show Abstract
The paper aiming at the influence factor of round grating dividing error, rolling-wheel produce eccentricity and surface
shape errors provides an amendment method based on rolling-wheel to get the composite error model which includes all
influence factors above, and then corrects the non-circle measurement angle error of the rolling-wheel. We make soft
simulation verification and have experiment; the result indicates that the composite error amendment method can
improve the diameter measurement accuracy with rolling-wheel theory. It has wide application prospect for the measurement accuracy higher than 5 μm/m.
A new approach for designing 2-D quasi-equiripple zero-phase FIR digital filters
Author(s):
Qiao Fu;
Xiaohua Wang;
Tianzan Li
Show Abstract
A batch back-propagation neural networks (BBPNN) approach was presented to design general two-dimensional (2-D)
quasi-equripple zero-phase finite-impulse response (FIR) digital filters. By minimizing the frequency-domain weighted
error function, the BBPNN design method was obtained. The solution was presented as a parallel algorithm to approximate
the desired frequency response specification. Thus, the method makes a fast calculation of the filter's coefficients
possible. It is shown that the method leads to an optimal solution for the filter coefficients. The implementation of the
approach was described together with some design guidelines, and some optimal design examples were given to demonstrate
the effectiveness of the proposed approach.
A novel method for chirp signal detection based on fractional Fourier transform
Author(s):
Qiufeng Shang;
Wenyan He
Show Abstract
A new method for chirp signal detection based on Fractional Fourier Transform (FRFT) is described in order to improve
the performance of power line communication system. A character of chirp signal is that its energy can be concentrated
properly when the fractional Fourier angle is suitable, but noise does not have this feature, signal mixed with noise can
be separated in specific fractional Fourier domain, and then narrow-band filter is adopted for the signal obtained in the
fractional Fourier domain, this character can be used for signal detection and then demodulation. Finally, simulation
experiments indicate that the method is feasible and the capacity of the system's anti-noisy disturbance is improved.
Audio steganalysis based on factor analysis and support vector machine
Author(s):
Jinsha Yuan;
Yincheng Qi
Show Abstract
Factor analysis (FA) is a multivariate statistical method for studying the correlation among a group of variables, and is
able to minimize data redundancy and reveal hidden patterns. We used FA to reduce the dimension of feature vector and
support vector machine to classify the audio data sets in the proposed audio steganalysis system. Then the system is
utilized to detect the stego-audio signals embedded by wavelet domain LSB, quantization index method (QIM) and
addition method (AM). The dimension of feature vector is decreased from 36 to 7 (LSB), 6 (QIM), 6 (AM) respectively.
The detection rates are all greater than 91% and the detecting performance is maintained.
The azimuth error compensation for inclinometer based on gyrocompass
Author(s):
Yanshun Zhang;
Yue Wang;
Hong Li
Show Abstract
The azimuth error of inclinometer based on gyrocompass changes with different azimuths and incline angles. It has
good repeatablility, but it is hard to be described in analytical expression. So a two-dimension look-up table method is
proposed to compensate the azimuth error. The testing data in turn-table is used to form the two-dimension data table,
which reflects the relationship among the azimuth error, the azimuth and incline angle. And the error characteristic of
azimuth error is expressed exactly. Combined with the look-up table method and interpolation method, the azimuth error
can be solved exactly and continuously. Turn-table experiments show that this method can increase the measurement
accuracy of azimuth greatly, and it has been used for practical orientation in oilfield successfully.
A global calibration method for multi-sensor vision system
Author(s):
Zhen Liu;
Guangjun Zhang;
Zhenzhong Wei
Show Abstract
A global calibration method of multi-sensor vision system based on flexible 3d target is proposed to solve the calibration
problem of multi-sensor vision system with a large inspection range. The flexible 3d target is a form of target consisted
of several planar targets, called sub-targets, which are placed flexibly according to the sensors' positions. The coordinate
frame of one of the vision sensor is selected as the global coordinate frame. Using the invariance of the relative positions
between sub-targets in the flexible 3d target, the closed solution of the transformation from the local coordinate frame of
each sensor to the global coordinate frame can be computed. The result is refined by the nonlinear optimization method,
and maximum likelihood estimation of the translation matrixes can be achieved. Experimental result demonstrates high
accuracy of proposed calibration method. The proposed method greatly simplifies the process and reduces the cost of
global calibration, for it does not need high-accuracy 3d measuring equipment or special 3d target as most the traditional
global calibration methods do, and only needs to combine several planar targets to carry out the global calibration. It is
applicable for the global calibration of multi-sensor vision system at working location.
An automatic test system for angular accelerometer
Author(s):
Shenghui Pan;
Bo Wang
Show Abstract
To assist the angular accelerometer manufacturing and acceptance, a reduced model equation is deduced based on the
principle of the angular accelerometer, an automated test system for electrical measurements is created, according to the
practical operating requirements in the application, with multifunctional single-axis rate table and DAS module control
by PC, and the software is developed in C++ Builder using multithread technology for fully automated testing through
signal acquisition and processing. Test procedure is suited to static tests and dynamic testing. In this paper, principles of
the automatic test system, application, and results are discussed.
Game theoretic analyses for free-riding and whitewashing in P2P systems
Author(s):
Jingcheng Ouyang;
Yaping Lin;
Siwang Zhou
Show Abstract
Conventional P2P networks do not provide incentives for users. Therefore, users can easily obtain information without
themselves contributing any information or service to a P2P community. This leads to the well known free-riding
problem. Reputation systems may impose penalties on free-riders to identify and distinguish them from contributors, but
these systems are vulnerable to the whitewashing attack. This paper analyzed the Tit-for-Tat protocol in the presence of
whitewashers using a game theoretic approach. The Tit-for-Tat protocol is not an evolutionary stable strategy against
invasion of whitewashing, but imposing an appropriate identity cost helps in preventing invasion by whitewashers.
Simulation results demonstrated the theoretic analysis, and showed that the percentage of cooperating nodes in P2P
networks with an appropriate identity cost is nearly four times bigger than without any identity cost.
A novel current mode biquadratic filter employing two current conveyors
Author(s):
Jing Zhao;
Jinguang Jiang;
Jingnan Liu
Show Abstract
The paper introduces a new current-mode biquadratic filter with three input terminals and one output terminal. The filter
proposed in this paper uses one plus-type second-generation current conveyor (CCII+), one dual-output second-generation
current conveyor (DOCCII), two grounded capacitors and three resistors. The circuit can realize all the
standard filter functions: high-pass, band-pass, low-pass, notch-pass, and all-pass by choosing appropriate input branches
without changing the passive elements. It has very low active and passive sensitivities, and can tune the circuit pole
parameters orthogonally. The performance of the proposed biquadratic filter was examined by PSPICE simulation.
Error comparison between ISO/WD 6358-2 and ISO 6358:1989
Author(s):
Jungong Ma;
Baolin Wu;
Juan Chen;
Zhiyong Tang;
Naotake Oneyama
Show Abstract
Flow-rate characteristics of pneumatic component are represented by sonic conductance C and critical pressure ratio b as
specified by ISO 6538. In this method, Components are considered having ellipse flow-rate characteristics. However,
since there are many of pneumatic components that ISO 6358 method can't represent proximately, regardless of whether
or not calculated component is independent or composed, the flow-rate characteristics curve is not always like an ellipse,
and the accuracy of sequential composition itself is questioned to air flow which passes though multiple components
simultaneously. For this reason, the modification of composition method is present which ISO/WD 6358-2 is. In the
paper, Error comparison between ISO/WD 6358-2 and ISO 6358:1989 have been done, the results show that error are
small between them, but ISO/WD 6358-2 extends the applicable range of standard.
Measuring system and method for auto-loading of bulk cargo
Author(s):
Li Shi;
JunJi He;
Gang Wu;
WeiJian Mi;
YouFang Huang
Show Abstract
Knowing the position of the chute of cargo loading machinery situated in its working environment is a critical element
for effectively accomplishing auto-loading of bulk cargo. This paper presents a novel approach to measure the position
of the chute as well as the status of ship being loaded. A measuring device was designed according to the approach based
on laser scanner and the measuring method was implemented. The system has been installed in actual cargo loading
environment and proved successfully and is believed that it is a good starting point to this kind of usage.
Uncertainty evaluation of calibration radon chamber
Author(s):
Shumin Zhou;
Bin Tang
Show Abstract
The uncertainty evaluation of calibration instrument is an important step to evaluate the performance of instrument. The
radon chamber is a standard instrument used to calibrate the radon monitors. Because the radioactivity decay and
statistical fluctuation of radioactivity measurement, the uncertainty evaluation of radioactivity measurement instrument
is different from the general instrument, the uncertainty evaluation of radon chamber should trace to the national
reference radium source. In this paper, the two different uncertainty evaluation model of radon concentration based the
radon source and radon monitor is described. The uncertainty of different input variables include radon concentration,
radioactivity statistical fluctuation, the temperature and humidity is evaluated in evaluation standard Type A or Type B.
According to the contribution of different factor to the uncertainty of radon concentration, the expanded and relativity
expanded uncertainty of radon chamber is calculated and discussed in detail. Through comparison, the uncertainty
evaluation of radon concentration based on radon monitor is better than the model based on radon source.
Test method for FOG loop eigenfrequency and half-wavevoltage based on square wave modulation
Author(s):
Ning-fang Song;
Jin-bao Zhang;
Dong-ying Ma;
Jing Jin
Show Abstract
A novel approach was presented to solve the problem of fiber optic gyro(FOG) loop eigenfrequency and half-wavevoltage
measuring. The method comes from the mechanism of reciprocal shift modulation, insteads of measuring
loop eigenfrequency it measures the optics power of ineffective-modulation that having a peak; and insteads of
measuring half-wavevoltage it measures the optics power of effective-modulation that having a low plain part. The
modulation square wave whose frequence and amplitude could be programmed is made of the technique of direct digital
synthesis. The scheme was tested by Matlab simulation, and implemented in circuit. The result of the loop
eigenfrequency and half-wavevoltage is much more preciser than handwork test, what's more, it takes much less time.
Investigation on reference value error in multivariate calibration
Author(s):
Qingbo Li;
Guangjun Zhang;
Xiang Li;
Kexin Xu;
Yan Wang
Show Abstract
Near infrared spectral analysis is a kind of indirect measuring technology, that is, calibration model is established by
using sample spectra and the reference value of the interested concentration, and then predict the interested concentration
of the unknown sample by using its spectrum and calibration model. Generally, the quality of calibration model is
evaluated by the deviation between the predicted value and the reference value of the measured concentration. Reference
value measurement error of the calibration set samples and model error are the main error source of multivariate
calibration. When there was reference value measurement error, the regression model would cause great prediction
deviation. However in practical application, apparent prediction error caused by reference value measurement error is
always considered as the faultiness of calibration model. So it is falsely regarded that the prediction error of multivariate
calibration model would be greater than that of reference method. In this paper, effect of reference value measurement
error on prediction error was analyzed, and the relationship among apparent prediction error, actual prediction error and
reference value measurement error was discussed. At the same time, the applicability and rationality of a computation
formula was also discussed, which could estimate the true prediction error in a more precise way. It was proved that the
prediction accuracy of an excellent calibration model was greater than that of the reference method by analyzing the
reference value measurement error. An experiment of glucose aqueous solution samples was given in this paper. In this
example, the effect of reference value measurement error on the prediction error of multivariate calibration model was
investigated, and the estimating formula of the corrected prediction error was evaluated. The conclusion could be
universally applied to not only multivariate calibration MLR, PCR, PLS and so on, but also in much more complex
samples.
Signal feature extraction based on wavelet fuzzy network with application to mechanical fault diagnosis
Author(s):
Lin Liu;
Huaying Wang
Show Abstract
To improve the performance of fault diagnosis technology for vibrant faults of aeroengine, a novel approach combining
the wavelet transform with fuzzy theory is proposed. The method with statistic rule is used to determine the threshold of
each order of wavelet space and the decomposition level adaptively, increasing the signal-noise-ratio. The effective
eigenvectors are acquired by wavelet transform and the fault patterns are classified by fuzzy diagnosis equation based on
correlation matrix. The fault diagnosis model of aeroengine is established and the extended Kalman filter algorithm is
used to fulfill the network structure. Also the robustness of fault diagnosis equation is discussed. By means of choosing
enough samples to train the fault diagnosis equation, the type of fault can be determined on basis of the input information
representing the faults. The actual applications show that the proposed method can effectively diagnose vibration fault of
aeroengine.
Adaptive PSO using random inertia weight and its application in UAV path planning
Author(s):
Hongguo Zhu;
Changwen Zheng;
Xiaohui Hu;
Xiang Li
Show Abstract
A novel particle swarm optimization algorithm, called APSO_RW is presented. Random inertia weight improves its
global optimization performance and an adaptive reinitialize mechanism is used when the global best particle is detected
to be trapped. The new algorithm is tested on a set of benchmark functions and experimental results show its efficiency.
APSO_RW is later applied in UAV (Unmanned Aerial Vehicle) path planning.
Dynamic time-frequency analysis approach for power quality disturbance in distribution power system
Author(s):
Weijian Huang;
Wenzhi Tian
Show Abstract
Power quality (PQ) is becoming prevalent and of critical importance for power industry recently. The quantitative
detection of two distortions of voltage waveform, i.e., voltage sag and voltage swell, is conducted and on this base a
novel approach based on wavelet transform (WT) to detect and locate the PQ disturbances is proposed. The signal
containing noise is de-noised by wavelet transform to obtain a signal with higher signal-to-noise ratio, and then is input
to the wavelet network; the synthesized method of recursive orthogonal least squares algorithm and improved Givens
transform is used to fulfill the network structure; the fundamental component of the signal is estimated to extract the
mixed information using wavelet network, and then the disturbance is acquired by subtracting the fundamental
component; the principle of singularity detection using WT modulus maxima is presented and a dyadic wavelet
transform approach for the detection and localization of the power quality disturbance is proposed. The simulation
results demonstrate that the proposed method is effective.
Application of the least square filtering in initial alignment of SINS
Author(s):
Long Zhao;
Li Wang
Show Abstract
When the statistics of the system noise and the observation noise are unknown, or almost unknown, the state estimation
error computed by Kalman Filtering will be much bigger, or the Kalman Filter may become divergence. In order to avoid
this demerit, a Least Square Filtering is presented. It weighs the observation data adaptively only without the
requirement of the statistics of the noise. This algorithm is used to Strapdown Inertial Navigation System (SINS) initial
alignment and compared with the Kalman Filtering. The simulation results show that the Least Square (LS) Filtering has
faster convergent speed than the Kalman Filtering.
Mass flow-rate measurement of oil-water two-phase flow based on differential pressure and adaptive wavelet network
Author(s):
Jun Han;
Feng Dong;
Wei Li;
Yaoyuan Xu
Show Abstract
Measurement of the oil-water flow is of great importance in the industrial process. In the paper, a soft-measurement
method for oil-water mass flow-rate was brought forward, in which the V-cone differential pressure meter was used and
the adaptive wavelet network was developed to achieve the soft-measurement of the mass flow-rate. The multi-input
single output model of adaptive wavelet network was adopted to approximate the mass flow-rate of oil-water. The paper
focused on the experimental measurement of the homogeneous model of oil-water two-phase flow in horizontal pipe.
Experimental results showed that the soft-measurement method combined differential pressure with adaptive wavelet
network could satisfy the demand of the mass flow-rate measurement and the measurement error of the mass flow-rate
was relatively small. The measurement error of the total mass flow-rate was acceptable.
An efficient distributed navigation algorithm for mobile robot
Author(s):
Xiuping Yang;
Songyan Liu;
Zhen Liu
Show Abstract
An efficient distributed algorithm for mobile nodes of wireless sensor network (WSN) is proposed. A smart mobile robot
is designed as the special node of WSN, and the nodes of WSN are deployed in the environment as signposts for the
robot to follow. We use the RSSI value between the robot and other static nodes as the input of the navigation control
system. The mobile robot state and navigation space are denoted by the RSSI potential field. Navigation directions are
computed by using fuzzy logic method. To reduce the communication expense, each node within one hop
communication range of robot is a distributed navigation unites. Then the fuzzy logic control centre will collect the
control outputs from every beacon nodes and calculate the final outputs for mobile robot based on data fusion. The
experimental results confirm that the navigation system based on WSN successfully achieved their assigned tasks.
A study on high-speed data acquisition system for single ended traveling wave fault location
Author(s):
Jian-hui Song;
Feng Yuan;
Zhen-liang Ding;
Zhuang-cheng Liang
Show Abstract
Single ended traveling wave fault location technology has been commonly used for testing cable for years. The
waveform attenuation and distortion of the reflected pulse is an inherent problem to define the arrival time and the
propagation velocity of traveling wave correctly. Aim at obtaining the required information of the incident and reflected
pulse waveform, a high-speed data acquisition system is designed based on the technology of random equivalent
sampling (RES). And the problem of data storage and communication caused by high sampling rate is solved. The high-speed
data acquisition system consists of fine time interval measurement module with 65ps resolution which is the key
technology of RES, relatively low-speed A/D converter, Field Programmable Gate Array (FPGA), high-speed
Synchronous Dual-Port RAM buffering storage and high performance programmable digital signal processors (DSP).
The data acquisition and storing of the system is realized with FPGA and DSP as the core. The system promises
15.4GHz equivalent sampling rates with 125MHz real-time sampling rate. Experiment proved that the high-speed data
acquisition system is stable and accurate.
Research on image-stabilizing system based on gyro-stabilized platform with reflector
Author(s):
Zhiyong Tang;
Zhongcai Pei;
Baolin Wu
Show Abstract
The optical stabilized platform is important equipment for observing on vehicle. A kind of stabilized platform was
introduced in this paper. In order to overcome the limitation of traditional compensation control, the double close loop
based on displacement feedback loop and speed feedback loop was presented. The PID was used in speed feedback loop,
and the fuzzy neural network (FNN) is used in displacement feedback control. The method united the fuzzy control and
neural network, fuzzy control needn't build precise object model and can simulate the human experiences, and the neural
network has the capabilities of self-learning and self-adaptation. So the FNN can adapt the change of parameters and
disturbance. In order to prove the effectiveness of this controller, simulations have been done.
Design and implementation of bridge remote data acquisition and monitoring system based on GPRS network
Author(s):
Xuemin Zhang;
Zenggang Xiong;
Shuang Pan
Show Abstract
Structural health monitoring for bridge is becoming a more widely accepted way to improve bridge management. To
implementation the above objective, this paper presents a GPRS-based bridge remote data acquisition and monitoring
system. It is a kind of unmanned automation, intelligent data acquisition system. The network structure of the system,
data transmission, information collection and data-processing model methods provide a common, advanced and effective
information acquisition model for other supervisory control and data acquisition systems. This system are highly portable
with little changes can be applied to other systems. These will not only improve the automation degree of monitoring,
and also a lot of human and financial resources are saved with a high practical value and economic value.
Implementation of resolver excitation and resolver-to-digital conversion system based on DSP
Author(s):
Xiangbo Xu;
Jiancheng Fang
Show Abstract
In order to improve the integration of control moment gyro (CMG) gimbal servo system, this paper proposes a resolver
excitation and resolver-to-digital conversion system based on digital signal processor (DSP). Only PWM, A/D functions
of one DSP and a few peripheral circuits can afford to supply excitation to resolver, demodulate the resolver outputs and
transform them into digital form. For decoding the resolver outputs, a simple inverse tangent method using a short
lookup table is introduced. Sallen-Key low-pass filter, FIR band-pass filter, coarseness-precision combing with its error
correction and a close-loop control method can improve angle solution and obtain velocity. Then angle and velocity are
fed back to angle loop and velocity loop of the gimbal servo system to make the whole system very integrated. The main
features include: easy realization, small bulk, light weight, low cost, adjustable parameters and wide uses. Experimental
result shows that the angle precision can reach 17 bits.
An active MBBNTree classifier learning from unlabeled samples
Author(s):
Yong C. Cao;
Yue Zhao;
Xiu Q. Pan;
Yong Lu;
Xiao N. Xu
Show Abstract
Obtaining labeled training examples for some classification tasks is often expensive, such as text classification, mail
filtering, while gathering large quantities of unlabeled examples is usually very cheap. Active learning aims at reducing
the number of training examples to be labeled by automatically processing the unlabeled examples, then selecting the
most informative ones with respect to a given cost function for a human to label. MBBNTree algorithm, which
integrates the advantage of Markov Blanket Bayesian Networks (MBBN) and Decision Tree, would behave better
performance than other Bayesian Networks for classification. But the available training samples with actual classes are
not enough for building MBBNTree classifier in practice. In this paper, the MBBNTree classifier algorithm based on the
Query-by-Committee of active learning would be presented to solve the problem of learning MBBNTree classifier from
unlabeled samples. Experimental results show that the proposed algorithm can reach the same accuracy as passive
learning with few labeled training examples.
Changes of trabecular bone under control of biologically mechanical mechanism
Author(s):
C. Wang;
C. Q. Zhang;
X. Dong;
H. Wu
Show Abstract
In this study, a biological process of bone remodeling was considered as a closed loop feedback control system, which
enables bone to optimize and renew itself over a lifetime. A novel idea of combining strain-adaptive and damage-induced
remodeling algorithms at Basic Multicellular Unit (BMU) level was introduced. In order to make the outcomes get closer
to clinical observation, the stochastic occurrence of microdamage was involved and a hypothesis that remodeling
activation probability is related to the value of damage rate was assumed. Integrated with Finite Element Analysis (FEA),
the changes of trabecular bone in morphology and material properties were simulated in the course of five years. The
results suggest that deterioration and anisotropy of trabecluar bone are inevitable with natural aging, and that
compression rather than tension can be applied to strengthen the ability of resistance to fracture. This investigation helps
to gain more insight the mechanism of bone loss and identify improved treatment and prevention for osteoporosis or
stress fracture.
A new cross-diamond search algorithm for fast block motion estimation
Author(s):
Shiping Zhu;
Xiaodong Shen
Show Abstract
In block motion estimation, search patterns have a large impact on the searching speed and quality of performance.
Based on motion vector distribution characteristics of real world video sequences, we propose a new cross-diamond
search algorithm (NCDS) using cross-search patterns before large/small diamond search patterns in this paper. NCDS
employs halfway technique to achieve significant speedup on sequence with (quasi-) stationary blocks. NCDS employs
Modified Partial Distortion Criterion (MPDC), which results in fewer search points with similar distortion. Experimental
results show that the improvements of NCDS over CDS can be up to a 16% gain on speedup while similar prediction
accuracy is maintained, and NCDS provides faster searching speed and smaller distortions than other popular fast block-matching
algorithms.
Study of two assessment methods for multi-parameter measurement instrument precision
Author(s):
Xiao-fang Zhong;
Si-feng Liu
Show Abstract
How to comprehensively assess precision of the Multi-parameter measurement instruments is becoming a hot research
topic in academy. In this paper, the precision of the multi-parameter measurement instruments is assessed using the
methods of MTS (Mahalanobis-Taguchi System) and grey incidence degree analysis through practice case study. The
study illustrates that both methods are applicable in the assessment of the Multi-parameter measurement instrument
precision. Through the comparison and contrast analysis, this paper summarizes the advantages and disadvantages of the
two methods, which provides good references or guidelines to properly apply the methods under different situations.
Calibration of prismatic joints in multi-axis machine tools by a three lines measuring method
Author(s):
Abdul Wahid Khan;
Wuyi Chen
Show Abstract
A three line calibration method for error quantification in a prismatic joint of a machine tool was proposed and
implemented by using a laser interferometer as a working standard. It greatly simplified the measurement setup
requirements and accelerated the calibration of prismatic joints. Moreover, it was highly economical by reducing the
calibration time and eliminating the use of complex optics. The methodology was implemented on prismatic joints of a
three axis CNC machine tool as per standard procedures and guide lines. Cubic spline technique was implemented as
error modeling and results obtained were reported for its further use to compensate the errors for improving the accuracy
in prismatic joints.
Research on a novel high sensitivity MOEMS deformable nano-grating accelerometer
Author(s):
Bo Zhang;
Zhikai Fan;
Lishuang Feng;
Qunyan Zhang
Show Abstract
With the development of the military field, there is growing interest in extremely high sensitivity. For meeting this desire,
we design a novel high sensitivity MOEMS (Micro-Opto-Electro-Mechanical-System) accelerometer which is based on
laterally deformable nano-grating. Calculations predict that this sensitivity could be improved by up to two orders of
magnitude in future design and it can reach as high as 10-9g. These sensors consist of two offset layers of sub-wavelength
polysilicon nano-gratings. They modulate the near-field intensity and polarization of an incident light source in response
to relative motion of the nano-gratings. The reflected/transmitted optical beam intensity from the nano-gratings is
measured as a function of the relative lateral positions of the nano-gratings. By using rigorous coupled-wave analysis
(RCWA) and Fourier transform methods, we research the theory mechanism about nano-grating accelerometer. The
accelerometer belongs to displacement sensors. For small changes in the spacing of the grating elements, a large change
in the optical reflection and transmission amplitude observed. An in-plane motion detection sensitivity of 160fm/√HZ has been measured, and its displacement sensitivities will be as low as 12fm/mg. This sensitivity compares favorably to
that of any other MEMS (Micro-Electro-Mechanical-System) transducer.
A personalized service oriented pragmatic-context architecture and supporting system
Author(s):
Yuanchun Li;
Xianghong Zheng
Show Abstract
The use of context is important in Human-Computer Interface services and become the focus of research on Pragmatic
Web embedded in instrumentation where the user's context is changing rapidly. We are interested in the content, type
and role of pragmatic-context, as swell how to use it in services embedded in instrumentations. In this paper, we propose
an overview of the pragmatic-context definition, description and, in particular, a generic model and framework that deal
with pragmatic-context in order to provide users with more tailored personalized services.
An improved adaptive tracking algorithm based on "current" statistical model
Author(s):
Mei Yuan;
Jiong Chen;
Xu Liang
Show Abstract
In order to track aerial target using data from radars, we improved an adaptive extended Kalman filtering algorithm
based on "Current" Statistical Model. In this improved algorithm, the interval of acceleration probability distribution is
adjusted, and Singer model is adopted instead of "Current" Statistical Model when target in the low-level maneuver.
According to the real-time estimation of acceleration and its change rate, self-adaption of extremum of acceleration is
achieved. Based on the Monte Carlo simulation, we got the conclusion that aerial target in different maneuver situation
can be tracked quickly, especially in the low-level maneuver, the improvement of tracking precision is notable.
A novel FIR filter design based on clonal selection algorithm
Author(s):
Qiusheng Wang;
Shaokun Gao;
Jingpo Zhao
Show Abstract
FIR filter has some advantages, such as system stability, simple implement, and linear phase. It has been widely used in
digital signal processing and other relative fields. Clonal selection algorithm has been applied successfully in solving
problems like memory acquisition, multi-modal optimization and traveling salesman problem. This paper proposes a
novel FIR filter design method. It combines clonal selection algorithm and window function method to achieve
optimization. In the design process, float coding is adopted to increase the convergence precision. Some simulation
experiments are carried out to verify the performance of the presented algorithm. The results show that the introduced
method is able to design some FIR filter which is difficult for other methods. The filter design approach discussed in this
paper is universal and easy to implement.
Improved void fraction measurement by flow regime identification for gas liquid two-phase flows
Author(s):
Chunguo Jing;
Quiguo Bai;
Bin Liu
Show Abstract
The gamma ray scattering energy spectrum detected by one detector was presented to distinguish the gas liquid two-phase
flow regime of vertical pipe. The simulation geometries of the gamma ray scattering measurement were built using
Monte Carlo software Geant4. Computer simulations were carried out with homogeneous flow, annular flow and slug
flow. The results show that the scattering energy characters of homogeneous flow and annular flow have significantly
different. The scattering spectrum of slug flow has a little similar to homogeneous flow or annular flow while gas slug
exists too short or too long in measuring cycle. The RBF neural networks were used to predict the flow regime. The
results show that the homogeneous flow and annular flow can be completely distinguished and the mostly slug flows
were exactly recognized by the neural network. It is demonstrated that the method of one detector scattering energy
spectrum has the ability to identify the typical gas liquid flow regime of vertical pipe and fit the applications in
engineering. The void fraction precision was improved by the flow regime compensation.
Biological fluid rheological property test system based on cone plate speed attenuation method
Author(s):
Mu Zhou;
Lianqing Zhu;
Mingli Dong
Show Abstract
In order to test the rheological property of biological fluid more simply and more accurately test, a cone plate speed
attenuation method is put forward on the base of spinning cone plate method. The cone plate is firstly driven by an eddy
coil to a preset value. Then the cone plate attenuates freely under the action of a fluid viscosity force. In the system,
standard viscosity oil is applied to calibrate measurement parameters and thus to eliminate systematic errors. The system
employs an upper computer and a lower microprocessor and adopts broadcast communication in a master/slave manner
based on RS485 serial links. The microprocessor is a LPC2131 for measuring the angular speed and the angular
acceleration of the cone plate and for controlling sampling and cleaning. The upper computer is programmed with the
language of Visual c++ 6.0, for data processing, data storage and data displaying. The repeatability error of the system, in
which the measurement is conducted with a standard non-Newtonian fluid, is 0.57%.
A fast initial alignment method for SINS on stationary base
Author(s):
Sheng Yang;
Jiancheng Fang
Show Abstract
In case of initial self-alignment for SINS on stationary base, when the level accelerometer outputs are taken as the
measurement value for Kalman filter, the convergence speed of azimuth misalignment angle is limited by the
observability of SINS. A fine alignment method for SINS is introduced firstly, which can do the accelerometer-based
leveling alignment and gyro-based heading alignment simultaneously. The observability analysis by Singular Value
Decomposition for this method shows that, the degree of observability of SINS is improved by adding observable extern
information. Based on the analysis, a fast initial alignment method is proposed, which employs a reduced order
alignment Kalman filter and takes both the level accelerometer outputs and east gyroscope output as the measurement
value. Besides, the model error compensation method is given. Simulation and experimental comparison results between
this fast alignment method and traditional one illustrate that, the convergence speed of azimuth misalignment angle is
improved greatly with good real-time performance.
An analysis on the theory of pulse oximetry by Monte Carlo simulation
Author(s):
Shangchun Fan;
Rui Cai;
Weiwei Xing;
Changting Liu;
Guangfei Chen;
Junfeng Wang
Show Abstract
The pulse oximetry is a kind of electronic instrument that measures the oxygen saturation of arterial blood and pulse rate
by non-invasive techniques. It enables prompt recognition of hypoxemia. In a conventional transmittance type pulse
oximeter, the absorption of light by oxygenated and reduced hemoglobin is measured at two wavelength 660nm and
940nm. But the accuracy and measuring range of the pulse oximeter can not meet the requirement of clinical application.
There are limitations in the theory of pulse oximetry, which is proved by Monte Carlo method. The mean paths are
calculated in the Monte Carlo simulation. The results prove that the mean paths are not the same between the different
wavelengths.
A field test and calibration system for production safety monitoring systems
Author(s):
Yang Liu;
Weiwei Xing;
Shangchun Fan
Show Abstract
This paper introduces a field testing and calibrating system that serves the national industrial standards of production
safety. The system supervises the monitoring systems of hazardous sources by measuring and evaluating them in the
field. The system is designed as a cabinet that can be carried by an automobile. The front end parts of the system are
designed as intrinsically safe handset instruments, so that they can be moved into Zone 0 independently and measure the
supervised devices as close as possible. Measurement accuracy of the instruments is guaranteed by design. The system
also provides a calibration interface with upper standard devices to facilitate periodically automatic calibration itself.
Improved delay-dependent stability criteria for neutral Hopfield neural networks
Author(s):
Minglei Zang;
Linyao Wu;
Qiuye She;
Zhongyi Chu
Show Abstract
The neutral Hopfield neural network (NHNN) model is considered in this paper, which can be regarded as an extension
of the classical Hopfield neural network (HNN). By introducing the neutral term into the classical HNN model, the
inspiration and associate memory phenomenon can be well described and explained. Based on LMI techniques, the
delay-dependent stability criteria of NHNN are obtained using the free-weighting matrices method, where the free
weighting matrices are applied to express the relationships between the terms in the Leibniz-Newton formula. The
optimization on the free weighting matrices by means of solving linear matrix inequalities (LMIs) can be employed such
that the less conservative results can be obtained than that in Zhang, et al 2005. The numerical examples demonstrate
that the proposed stability criterion is less conservative than the previous works.
Simple linearization of measurement based on photovoltaic voltage
Author(s):
Changsheng Li
Show Abstract
Based on the logarithmic relationship between photovoltaic voltage and incident light intensity of a photo-detector, a
simple and low-cost method is proposed to linearize the measurement of nonlinear variables related to light intensity.
Theoretical analysis shows that this linear measurement method is feasible in a large measurement range if we choose a
proper load resistance for the photodiode. Based on the Lambert-Beer law and the photovoltaic voltage-based
measurement method, the linear measurements of liquid level and liquor concentration have been achieved
experimentally by directly detecting the output voltage of a solar cell, and their nonlinearities are both less than 2.0%.
Analysis of measuring error for AFVISAR system
Author(s):
Lin Wang;
Xiao-feng Meng;
Zhao-hai Lv
Show Abstract
AFVISAR (all fiber velocity interferometer system for any reflector), which is developed from laser Doppler method,
has been proved to be effective and powerful technique in acceleration (and velocity) measurement. The measuring error
of AFVISAR system must be studies in order to achieve accurate measure result. However, the existing theoretical
research about this problem is inadequate.
In this paper, firstly, the principle of AFVISAR is analyzed with Doppler frequency shift theory and the mathematic
equations for acceleration calculating are concluded. The theoretical model of the measuring error is put forward by
considering object moving direction bias angle and corresponding expression of the deviation is established. Then, an
example is taken to illustrate the effect that the bias angle brings to acceleration calculation. In the following paragraph,
the error creating by ignoring the second-order Doppler frequency shift is analyzed and the calculation formulas are
demonstrated. Finally, the effect of the spectral characteristics of fiber laser are studied, and the relative error is
calculated.
Long-term stability analysis for atmospheric pressure standard
Author(s):
Xiaolei He;
Jianying Li;
Yizhou Sha;
Wei Li
Show Abstract
With summarizing the stability assessment data over 10 years to the atmospheric pressure standard (Ruska2465-754,
SN45158) established by National Center for Meteorological Standard Metrology, it is proven that the mass equipped by
instrument is with good stability, the effective area of piston is about stable, the pressure reproducibility and
measurement capability is stable for over 10 years and obviously better than nominal accuracy specification.
The gear pair integration error curve and its atlas
Author(s):
Yan Kang;
Zhao-yao Shi;
Jia-chun Lin
Show Abstract
The insufficiency of single-flank testing is analyzed. Today's solutions and their existing problems are discussed. Based
on this, the gear pair integration error (GPIE) is used to efficiently eliminate the insufficiency of the single-flank testing.
GPIE takes all errors of a gear pair as a set, and this set is represented by the gear pair integration error curve (GPIEC)
which is formed in the way that the deviations of all points on conjugate tooth flanks of the gear pair are marked with the
same base zero and are arranged along the action line of the gear according to the meshing sequence of the
correspondent mesh points. An introduction of the deduction of this theory and its definition formula, as well as the
synthesis method of the GPIEC are presented. Finally, the feasibility and efficiency of the theory are demonstrated in
resolving the insufficiency of the single-flank testing and analyzing the sources of transmission quality and gear noise
through the comparison between the GPIEC of a gear pair and its transmission error curve. The significance of the
theory are summarized with respect to their influence upon formulating standards for gear tolerance, analyzing errors of
gear-cutting machines and transmission quality of the gear pair, and innovating ways to the research of the dynamic
characteristics of gears and their noise.
Focusing on accelerated life testing for cylinders
Author(s):
Juan Chen;
Jungong Ma;
Zhanlin Wang;
Andreas Wank
Show Abstract
The study of accelerated life test on cylinders for pneumatic industry is covered in this paper. Accelerated life testing is
valuable tools to get information quickly on life distribution which is achieved by subjecting the test units to conditions
that are more severe than the normal ones. Long lifetime pneumatic cylinders are selected as the test object. Section I
covers the fault mechanism analysis, the piston and piston pole parking are the weak units as they are movable parts as
well as leakage sources which easily result in the cylinders failure. Liquid temperature and operating frequency are
chosen as stresses since their accelerating potentials are available for the specific cylinders. The complete ALT data is
presented using Weibull distribution. Estimation for the parameters of failure model and other characteristics of cylinders
population life distribution are done successfully. From the 3-axis graph plotted, the effects of each stresses to cylinders
can be seen clearly which provide useful results for cylinders researcher and developer.
Fast tracking mode predictive centroiding scheme
Author(s):
Masood-Ur Rehman;
Jiancheng Fang;
Faycal Saffih;
Wei Quan
Show Abstract
The autonomous star trackers, using charge couple device CCD camera, or active pixel sensor APS, as natural sensors
for optical input, has assumed a permanent position. This is due to their highly accurate attitude determination, small size,
light weight and simple functionality, making them devices of choice in nearly all modern space vehicles especially for
Nano-satellites. In all star trackers, star centroiding is a fundamental process necessary for pattern recognition. In this
paper, a new method is presented, which predicts centers of regions of star locations, in successive image frames, from
the current knowledge of boresight direction, which is updated successively. This method is very attractive for hardware
implementation using APS imagers known for their random accessibility feature lacked in CCD's. The big advantage of
this method is that it does not need pattern recognition, thus making it fast. This reduction of computational budget,
power consumption and time, added to the capability of incorporating them in APS imagers, is appealing to Nano-satellites
navigational instrumentation.
Nonlinear/linear combination filter for SINS alignment
Author(s):
Majeed Salman;
JianCheng Fang;
Fan Xu
Show Abstract
In order to improve the initial alignment accuracy of Strapdown Inertial Navigation System (SINS) in case of large
attitude errors, a combination of nonlinear Unscented Kalman Filter (UKF) and the linear Kalman Filter (KF) has been
considered. For large initial attitude errors, both in heading and the level plane, application of the KF to the linearized
error model of SINS does not yield good initial attitude estimation. To overcome this problem, the UKF has been
employed. Initially state feedback has not been applied to maintain the nonlinear nature of the system. It is applied at the
end of estimation using UKF. Simulation results for stable base SINS alignment have shown high level of accuracy for
heading estimation but not equally so for the level plane. However, after employing state feedback at this point linearized
approximation of the error model is justified. The superior performance of KF for linear systems is then exploited.
Simulation results show marked improvement as compared to the single use of UKF or the KF.
Current issues on 3D volumetric positioning accuracy: measurement, compensation, and definition
Author(s):
C. Wang
Show Abstract
Traditionally, manufacturers have ensured part accuracy by linear calibration of each machine tool axis.
The conventional definition of the 3-D volumetric positioning error is the root mean square of the three-axis
displacement error. 20 years ago, the dominate error is the lead screw pitch error of 3 axes. This
definition is adequate. However, now the machine accuracy has been improved with better lead screw,
linear encoder and compensation, the dominate errors become the squareness errors and straightness errors.
Hence the above definition is inadequate.
During the past years, the industry has seen demand emerge for the "volumetric accuracy" specification on
machine tools. One hurdle remains: a standard definition so that everyone measures volumetric accuracy
with the same yardstick. The issue has been discussed in many Standards Committees, machine tool
builders and the metrology community. Reported here are, a new 3D volumetric positioning error
measurement and compensation technique, proposed definitions or measures of 3 D volumetric positioning
errors of a CNC machine tool, and its verification.
Variation of rolling element bearing friction torque
Author(s):
Xintao Xia;
Zhongyu Wang
Show Abstract
The statistical characteristics of the rolling element bearing friction torque are analyzed to find its evolvement law, via
the experiment on the friction torque of two kinds of the bearings code-named HKTA and HKTB under the condition of
different rotational speeds. A concept, relative increment of the variation coefficient, is proposed for an in-depth study of
the evolvement course. According to the statistical calculating results for the experimental data, the higher the rotational
speed of the rolling element bearing is, the severer the variation of its friction torque is. Under the condition of the low
rotational speed range from 3r/min to 15r/min, the maximum of the relative increment of the variation coefficient can be
over 25%. This uncovers new evidence that the degree of the evolvement of the friction torque will become stronger and
stronger consequentially with the increase of the rotational speed of the rolling element bearing.
Region-based fractal video coding
Author(s):
Shiping Zhu;
Kamel Belloulata
Show Abstract
A novel video sequence compression scheme is proposed in order to realize the efficient and economical transmission of
video sequence, and also the region-based functionality of MPEG-4. The CPM and NCIM fractal coding scheme is
applied on each region independently by a prior image segmentation map (alpha plane) which is exactly the same as
defined in MPEG-4. The first n frames of video sequence are encoded as a "set" using the Circular Prediction Mapping
(CPM) and encode the remaining frames using the Non Contractive Interframe Mapping (NCIM). The CPM and NCIM
accomplish the motion estimation and compensation, which can exploit the high temporal correlations between the
adjacent frames of video sequence. The experimental results with the monocular video sequences provide promising
performances at low bit rate coding, such as the application in video conference. We believe the proposed fractal video
codec will be a powerful and efficient technique for the region-based video sequence coding.
A new spatial-temporal video object segmentation algorithm based on region compensation in fixed time interval
Author(s):
Shiping Zhu;
Yunyu Lin;
Qingrong Zhang
Show Abstract
A post-processing algorithm of video object segmentation that is based on region compensation in fixed time interval is
proposed on the base of the traditional spatial-temporal video object segmentation algorithm. Firstly, an image variation
detection template is calculated by noise suppression and dilatation linking of frame difference images; Secondly, the
morphological gradient is calculated by the simplification of morphological opening and closing reconstruction of the
original image. The accurate boundary of the object can be obtained by watershed algorithm through the nonlinear
transformation and gradient grade classification of the morphological gradient image. The initial binary template of the
video object can be extracted through proportion calculation; Thirdly, the final complete video object template can be
obtained through region compensation in fixed time interval. Experimental results indicate the correctness and validity of
the proposed video object segmentation algorithm.
The test technology of electrical safety performances based on IEC international standards
Author(s):
Xiaofei Wang;
Zhaohui Zhang;
Dong Li;
Yanlin Wang
Show Abstract
The test technology of electrical safety performance based on IEC international standards is put forward in the paper,
including mainly four test parameters: leakage current, high-voltage withstand, insulation resistance and ground
resistance. The definitions, the types, the testing purposes and methods of these parameters are also proposed. Based on
the technology, we construct a system for data collection, processing and controlling with a PC, a high-performance
microcomputer ADμC842 and a FPGA, and adopts a VI technology to develop an integrated testing system for electrical
safety performance. The system can be applied to both the certification testing of products and quality control in
manufacturing and provides an authenticating measure for the domestic electrical equipments to enter international
markets.
A new design of leakage current test system
Author(s):
Yiming Wang;
Xiaofei Wang;
Dong Li;
Chaozhen Yang
Show Abstract
The working principle, design and implementation are described for a new design of leakage current test system, which
is composed of human body's impedance network, detector switch circuit, the circuit including MCU and CPLD for
control and measurement, can achieve peak detection, true RMS detection, real-time display of waveform. According to
many international testing standards such as IEC, UL, GB, the system has a broader measuring scope of frequency and
higher accuracy with good human-computer interface and calibration function.
Dynamic decoupling nonlinear control method for aircraft gust alleviation
Author(s):
Yang Lv;
Xiaopeng Wan;
Aijun Li
Show Abstract
A dynamic decoupling nonlinear control method for MIMO system is presented in this paper. The dynamic inversion
method is used to decouple the multivariable system. The nonlinear control method is used to overcome the poor
decoupling effect when the system model is inaccurate. The nonlinear control method has correcting function and is
expressed in analytic form, it is easy to adjust the parameters of the controller and optimize the design of the control
system. The method is used to design vertical transition mode of active control aircraft for gust alleviation. Simulation
results show that the designed vertical transition mode improves the gust alleviation effect about 34% comparing with
the normal aircraft.
Eigenvalue assignment based on standard characteristic polynominal in design of aircraft control systems
Author(s):
Aijun Li;
Yang Lv;
Changqing Wang
Show Abstract
Design method of eigenvalue assignment based on standard characteristic polynomial, as well as mathematical solving
process of the method, is proposed in this paper so as to resolve the uncertainty of ideal eigenvalue choice in modern
control theory and the difficultly in engineering implementation of modern control system design methods. Longitudinal
stability holding control system of an aircraft was designed and simulated by employing proposed method. Dynamic
character and robust performance simulation of the system are given. Simulation results show that the method achieves
the control quality and has better robustness than another method. There is only one design parameter which is easy to
calculate. So, the method is characterized as simple design, logical structure, easy programming and convenient for
engineering implementation.
A fault-tolerant attitude control system for a satellite based on fuzzy global sliding mode control algorithm
Author(s):
Jinjin Liang;
Chaoyang Dong;
Qing Wang
Show Abstract
The structures and missions of modern satellites are very complicated, so the reliability of satellites is becoming
increasingly important. This paper proposed a fault-tolerant attitude control system for a satellite based on Fuzzy Global
Sliding Mode Control (FGSMC) algorithm. We designed a controller for the nonlinear model of a satellite. By designing
a global sliding surface, this controller can ensure that the response of the system has global robustness against the
uncertainties of system and external disturbances. In this paper attitude control is performed by four reaction flywheels.
The attitude control system distributed the three control torques to the four reaction flywheels according to the
distribution matrix. We deduced the formula to calculate the distribution matrix. Paper proved the stability of the
designed control law, and simulated the attitude control system. The simulation results show that the attitude control law
has high accuracy and robustness.
Performance measurement of fault pattern classification for aircraft engine based on wavelet network
Author(s):
Wei Liao;
Pu Han
Show Abstract
An effective approach for fault diagnosis of aeroengine based on integration of wavelet analysis and neural networks is
presented. The wavelet transform can accurately localizes the characteristics of a signal in time-frequency domains and
in a view of the inter relationship of wavelet transform between exponent theory, the whole and local exponents obtained
from wavelet transform coefficients as features are presented for extracting fault signals, which are inputted into radial
basis function for fault pattern recognition. The fault diagnosis model of aero-engine is established and the improved
Levenberg-Marquardt training algorithm is used to fulfill the network structure and parameter identification. By
choosing enough samples to train the fault diagnosis network and the information representing the faults input into the
neural network, the fault pattern can be determined. The robustness of wavelet neural network for fault diagnosis is
discussed. The practical fault diagnosis for aeroengine vibration approves to be accurate and comprehensive.
Adaptive second-order sliding mode attitude control of flexible spacecraft
Author(s):
Xiyuan Huang;
Qing Wang;
Chaoyang Dong
Show Abstract
A new adaptive second-order sliding mode control method is proposed for the attitude control of flexible spacecraft
during slew maneuver. Compared with traditional sliding mode control, the second sliding mode control approach
guarantees the same robustness and precision, feature higher order accuracy and can be exploited to eliminate the
chattering phenomenon. In the present paper, a second-order sliding mode controller is designed by treating the input of
the system as a new state variable, while using it's derivate as the actual control. A fuzzy-neural network is adopted to
approximate the strong coupling uncertain nonlinear dynamics, and the on-line adaptive weights tuning law is derived,
the global stability of the system is guaranteed. Simulation results show the effectiveness of the proposed method.
Adaptive sliding mode control on inner axis for high precision flight motion simulator
Author(s):
Yongling Fu;
Jianjun Niu;
Yan Wang
Show Abstract
Discrete adaptive sliding mode control (ASMC) with exponential reaching law is proposed to alleviate the influence of
the factors such as the periodical fluctuation torque of motor, nonlinear friction, and other disturbance which will
deteriorate the tracking performance of a DC torque motor driven inner axis for a high precision flight motion simulator,
considering the limited compensating ability of the ASMC for these uncertainty, an equivalent friction advance
compensator based on Stribeck model is also presented for extra-low speed servo of the system. Firstly, the way direct
using the available parts of the inner axis itself to ascertain the parameters for Stribeck model is listed. Secondly,
adaptive approach is used to overcome the difficulty of choice the key parameter for exponential reaching law, and the
stability of the algorithm is analyzed. Lastly, comparable experiments are carried out to verify the valid of the combined
approach. The experiments results show with a stable 0.00006°/s speed response, 95% of time the tracking error is within
0.0002°, other servos such as sine wave tracking are also with high precision.
A novel controller based on robust backstepping and neural network for flight motion simulator
Author(s):
Zhenghua Liu;
Yunjie Wu;
Weihong Wang
Show Abstract
The flight motion simulator is one kind of servo system with uncertainties and disturbances. To obtain high performance
and good robustness for the flight simulator, we present a robust compound controller base on Backstepping controller
and BP neural network. Firstly, the design procedure of the robust Backstepping controller is described and correlative
problems are proposed. Secondly, the principle and the design process of BP neural network are analyzed and expatiated
respectively. Finally, simulation results on the flight simulator show that the BP neural network can compensate external
disturbances including system input and output disturbance and the system performance can be improved. Therefore
both robustness and high performance of the flight simulator are achieved. It is an applied technology for the control of
servo system, such as the flight motion simulator.
Flight route choice research based on decreasing flights
Author(s):
Fuqing Dai;
Siying Xu
Show Abstract
Present scheduled flights are arranged between two airports as a pair of flights. This paper proposed a novel and
innovative method that one flight executes more scheduled flight plans over more airports and then come back to the
departure airport and at the same time another flight execute the opposite scheduled flight from the same departure
airport and come back to the airport from the opposite flight route. After a comparative analysis of various heuristic
algorithms[1], ant colony algorithm is selected to solve this problem. In this paper, choose eight airports as the research
objects and obtain the results with the help of computer. The outcome indicates the validity of the improved ant colony
algorithm.
On-line estimation and compensation of measurement delay in GPS/SINS integration
Author(s):
Tao Yang;
Wei Wang
Show Abstract
The chief aim of this paper is to propose a simple on-line estimation and compensation method of GPS/SINS
measurement delay. The causes of time delay for GPS/SINS integration are analyzed in this paper. New Kalman filter
state equations augmented by measurement delay and modified measurement equations are derived. Based on an open-loop
Kalman filter, several simulations are run, results of which show that by the proposed method, the estimation and
compensation error of measurement delay is below 0.1s.
The design for electrical signal source of infrared Earth-wave
Author(s):
Xinlin Yang;
Jianhui Zhao;
Tongbao Wang;
Yanjia Li
Show Abstract
In satellites attitude measurement, Infrared Earth Sensor (IES) is one of the key components. In order to accomplish the
testing and calibration of IES, a signal stimulated source is required to provide electrical earth-wave signal, so the
system design of Electrical Signal Source of Infrared Earth-Wave (ESSIEW) is very important during the R&D and test
of IES. Traditional system design of ESSIEW used digital circuits to implement so that its precision and security and
testing efficiency are low. By analyzing the task and requirement of testing and calibration in the uninstalled IES, a new
system design is proposed. The new system design includes two parts: hardware system and software system. The
hardware system implements by FPGA technology and DAC transformation technology, and the software system
implements by main-control software on CPU board and FPGA solidified software. The experiment and application
results show that the system of new design presented in this article has characteristics of high precision and high security
and full functions, improves the testing performance and efficiency of IES and satisfies with signal testing requirement of
the electrical signal source.
Vehicle tracking algorithm based on GPS and map-matching
Author(s):
Guixia Guan;
Lei Yan;
Jiabin Chen;
Taixia Wu
Show Abstract
In the land vehicle positioning and tracking system, the vehicle moving route is sometimes positioned outside the vehicle
running road because of the GPS positioning errors. It may cause the tracking system unavailable. In order to improve
the positioning accuracy of vehicle tracking system, a current statistical model is employed as the vehicle moving model.
At the same time, the map-matching algorithm with the nearest location and the suitable moving angle is proposed to
amend GPS measured data. The algorithm can determine the best matching road by making full use of the road
geographic information of electronic map. Simulation results show that the vehicle tracking system has high positioning
accuracy besides the navigation function.
Switched control system for satellite formation configuration
Author(s):
Zhang Chen;
Chaoyang Dong;
Qing Wang
Show Abstract
In this paper formation configuration control of distributed satellites is studied based on continuous micro-thrust. The
nonlinear model for the Leader/Follower relative position case is derived. A sliding mode relative position controller is
designed based on the dynamic equations, which is proved to be able to eliminate the influence of J2-perturbation. As it
is difficult to develop a globe control law for all the missions during the formation, a switching-mechanism is adopted
according to the hierarchical architecture of the system. A supervisor in the upper layer controls the transition between
the modes. Dwell time and safe mode are applied to ensure the stabilization of the switched system. Simulation results
show that the switched system proposed in this paper can control configuration of the formation to desired patterns
effectively and can still work even if the Leader satellite is malfunctioning.
Emulation of rocket trajectory based on a six degree of freedom model
Author(s):
Wenpeng Zhang;
Fan Li;
Zhong Wu;
Rong Li
Show Abstract
In this paper, a 6-DOF motion mathematical model is discussed. It is consisted of body dynamics and kinematics block,
aero dynamics block and atmosphere block. Based on Simulink, the whole rocket trajectory mathematical model is
developed. In this model, dynamic system simulation becomes easy and visual. The method of modularization design
gives more convenience to transplant. At last, relevant data is given to be validated by Monte Carlo means. Simulation
results show that the flight trajectory of the rocket can be simulated preferably by means of this model, and it also
supplies a necessary simulating tool for the development of control system.
A low cost integrated navigation system applied on UAV and some simulations results
Author(s):
Wei Liu;
Jingjuan Zhang;
Guoliang Yang
Show Abstract
The development of Un-manned Aerial Vehicles (UAV) is analyzed, and an integrated MEMS-SINS /GPS/ Pressure
Altimeter / Magnetic Compass is presented as an airborne equipment for UAV. In this low cost integrated navigation
system, the position and velocity precision can be ensured due to GPS, and the pitch and roll precision can be ensured
due to accelerometers. The heading's observability is very weak, in order to eliminate this divergent trend, the method
that dead reckoning revises the heading of SINS is put forward. The simulation shows that this method can effectively
eliminate the divergent trend of heading.
Analysis of key technologies in geomagnetic navigation
Author(s):
Xiaoming Zhang;
Yan Zhao
Show Abstract
Because of the costly price and the error accumulation of high precise Inertial Navigation Systems (INS) and the
vulnerability of Global Navigation Satellite Systems (GNSS), the geomagnetic navigation technology, a passive
autonomous navigation method, is paid attention again. Geomagnetic field is a natural spatial physical field, and is a
function of position and time in near earth space. The navigation technology based on geomagnetic field is researched in
a wide range of commercial and military applications. This paper presents the main features and the state-of-the-art of
Geomagnetic Navigation System (GMNS). Geomagnetic field models and reference maps are described. Obtaining,
modeling and updating accurate Anomaly Magnetic Field information is an important step for high precision
geomagnetic navigation. In addition, the errors of geomagnetic measurement using strapdown magnetometers are
analyzed. The precise geomagnetic data is obtained by means of magnetometer calibration and vehicle magnetic field
compensation. According to the measurement data and reference map or model of geomagnetic field, the vehicle's
position and attitude can be obtained using matching algorithm or state-estimating method. The tendency of geomagnetic
navigation in near future is introduced at the end of this paper.
A novel MOGA-based method of flight control law design for a helicopter and its application
Author(s):
Xiaojun Xing;
Dongli Yuan;
Jianguo Yan
Show Abstract
In order to design full-envelop flight control law for a certain helicopter, a novel method based on multi-objective
genetic algorithm (MOGA) is put forward. In this method, the design of flight control law is viewed as a multi-objective
optimization problem(MOP) where obtaining optimal performances in each designed flight envelop are treated as sub-objective
and that in all designed flight envelop as objective, flight control law's parameters to be searched as decision
variables, corresponding performance criteria as constraints. For the MOP, MOGA is used to get the optimal parameters
of flight control law in all designed flight envelops. Finally, the novel method is applied to the flight control law's design
for the helicopter's pitch motion, the simulation results show that the parameters are feasible and the performances are
satisfactory, which further prove that the method is effective.
Research on fast algorithm of small UAV navigation in non-linear matrix reductionism method
Author(s):
Xiao Zhang;
Jiancheng Fang;
Wei Sheng;
Juanjuan Cao
Show Abstract
The low Reynolds numbers of small UAV will result in unfavorable aerodynamic conditions to support controlled flight.
And as operated near ground, the small UAV will be affected seriously by low-frequency interference caused by
atmospheric disturbance. Therefore, the GNC system needs high frequency of attitude estimation and control to realize
the steady of the UAV. In company with the dimensional of small UAV dwindling away, its GNC system is more and
more taken embedded designing technology to reach the purpose of compactness, light weight and low power
consumption. At the same time, the operational capability of GNC system also gets limit in a certain extent. Therefore, a
kind of high speed navigation algorithm design becomes the imminence demand of GNC system. Aiming at such
requirement, a kind of non-linearity matrix reduction approach is adopted in this paper to create a new high speed
navigation algorithm which holds the radius of meridian circle and prime vertical circle as constant and linearizes the
position matrix calculation formulae of navigation equation. Compared with normal navigation algorithm, this high
speed navigation algorithm decreases 17.3% operand. Within small UAV"s mission radius (20km), the accuracy of
position error is less than 0.13m. The results of semi-physical experiments and small UAV's auto pilot testing proved
that this algorithm can realize high frequency attitude estimation and control. It will avoid low-frequency interference
caused by atmospheric disturbance properly.
Simulation of uniform bus alignment satellite power system
Author(s):
Fan Li;
Yanjia Li;
Jianhui Zhao;
Xinlin Yang
Show Abstract
The model of uniform bus alignment satellite power system, which based on Simulink technology, Adopts
Three-Domain control, considers the influence to the power system by the output of solar array and different load.,
computes the energy changing, simulate the uniform bus alignment satellite power system and energy balance, gives the
result. The result of simulation indicates that the high current/small current/trickle charge schedule was implemented in
charging regulator; the bus voltage was regulated to about 28V all the time; the power, current and voltage output of the
solar array and the battery meet the requirements of the satellite power supply in orbit.
Dual-band GPS occultation receiver
Author(s):
Qifei Du;
Yueqiang Sun;
Shijing Wang;
Guangwu Zhu;
Peng Tao;
Zhengting Liu;
Weihua Bai
Show Abstract
Dual-band GPS occultation receiver is designed to provide highly accurate measurements for atmosphere and
ionosphere. The instrument flying on low-Earth orbit (LEO) receives the signals that have crossed the atmosphere and
ionosphere at varying altitudes. It contains antennas, Radio Frequency Conditioning Units (RFCU) and central
Electronic Unit. Besides the usual real-time navigation, the instrument must accurately track a sufficient number of GPS
Space Vehicles (SV) for Radio Occultation (RO) and for precise orbit determination (POD), providing precise
dual-frequency carrier and code phase measurements for the RO application. Plenty of environmental data can be
deduced by way of further processing. This paper shows some data derived by mountain based observation experiment.
Satellite surface gas component detector
Author(s):
Hong Zeng;
GuoTai Qin;
Long Zhang
Show Abstract
Satellite Surface Contamination (OSC) has unneglectable effects on solar-array output power, connections between
solar-array, thermal blanket's functions, payloads' and optical sensors' performances onboard the Low Earth Orbit
(LEO) satellites (especially long lifetime satellites). It can even influence their actual life. There are many kinds of
examples in our country and overseas. In order to ensure satellites for long time working normally, we have set out to
monitor and analyze the satellite surface gas. To be an effective instrument, Satellite Surface Gas Component Detector
(SSGCD) is used to monitor the "in-situ" surface gas for the emergence and the variety with the change of time and
position, as well as to monitor and identify the gas component and its density. Through the data processing with Ground
Data Processing Unit (GDPU), we can evaluate the degree of the influence resulted from OSC, and provide services for
orbital fault analysis and disposal.
The solar EUV instrumentation onboard the Earth geostationary orbit satellite
Author(s):
Fei Wei;
Guangwu Zhu;
Jilong Peng;
Shijin Wang;
Huaan Lin
Show Abstract
Solar Extreme Ultravoilet (EUV) irradiance is one of the most important energy input source for the upper atmosphere.
It's responsible for the variation of the composition of upper atmosphere, vertical profile of the atmosphere density and
ionosphere's TEC. In order to investigate the solar EUV irradiance in different time scales, it's better to launch EUV
grating spectrograph covering the whole solar EUV spectrum. Because of the high contrast between the solar EUV
emission lines, it is possible to characterize the whole solar EUV spectrum by monitoring individual bright EUV
emission lines, such as the Lyman alpha emission line (121.6nm in wavelength) and the He-II emission line (30.4nm in
wavelength). The solar EUV instruments described in this paper are broad wavelength passband EUV monitors
respectively covering the emission lines of 30.4nm and 121.6nm. Additional important emission lines are optional, such
as 12.1nm, 58.4nm and 85.6nm. Each instrument covers just one emission line selected by a group of optic
components - a multi-metal-film filter selecting the EUV wavelength passband and a spherical multilayer-coated
reflecting mirror collecting the solar EUV irradiance from different incidence angle and improving the wavelength
resolution. This kind of design will be used in the case high accuracy solar pointing system is unavailable, and the strong
background of energetic charged particles is serious, such in the earth geostationary orbit, which is located in the limb of
outer radiation belt.
The design of high energy particle detector in satellites
Author(s):
Tao Jing;
Guangwu Zhu;
Yue Wang;
Huanxin Zhang;
Guohong Shen
Show Abstract
High energy particle detector is one of the common payloads in Chinese spacecraft. Its purpose is to detect the flux of
the high energy particle in space environment. This paper gives some information about the high energy particle
detector.
Integrated system of test data management and monitoring for the ground test of liquid rocket engine
Author(s):
Xue Yang;
Zhenpeng Zhang;
Jun Zhang
Show Abstract
An integrated system of test data management and monitoring (ISTDMM) for liquid rocket engine (LRE) ground test is
designed to meet the demand of the LRE test station and development unit according to the LRE test information and test
process. It is an opening, distributing and highly integrating application platform, mainly includes the test data
management systems, the real-time fault detection systems and data display and playback system. It can manage and
analyze the test data and simulation data of the LRE, can monitor the LRE test condition in real-time and the test process
in long-distance by network, and can playback the engine test process and simulate the engine work process, and can test
and evaluate the fault detection algorithms and systems of LRE. It is well advanced, reliable, and practical.
The scheme of satellite navigation performance evaluation and test system based on simulation
Author(s):
Xiaojing Xia;
Dong Xu;
Yan Zhao
Show Abstract
A satellite navigation performance evaluation and test system framework structure based on simulation has been
conceived and developed targeting the windows operating system, so as to extract and analyze he key performance of
satellite navigation system The evaluation methods of Ionospheric model errors, Space vehicles (SVs) clock errors and
Ephemeris prediction errors were presented. While testing physical receiver performance, the mathematical simulation
satellite navigation subsystem except receiver was used to help. It can provide references for satellite navigation
performance evaluation and test.