Volume 33,Issue 4,2010 Table of Contents

1 Multiobjective and H2/H control of vehicle active suspension based on LMI

LI Yinong , ZHENG Ling , LUO Minggang , MI Lin

2010, 33(4):1-8. DOI: 10.11835/j.issn.1000-582X.2010.04.001

[Abstract](2828) [HTML](0) [PDF 8.65 M](1568)

Abstract:
A multiobjective and mixed H2/H controller based on LMI(linear matrix inequality) is developed to balance ride comfort and handling stability performance of vehicle. The multiobjective optimal control law is devised for an active suspension system of seven degreeoffreedom fullcar model. Norm H2 of the transfer function from road profile velocity disturbance to output evaluating signal is selected as the evaluating index of ride comfort performance, and norm H of the transfer function from road profile velocity disturbance to output evaluating signal is selected as the evaluating index of handing stability performance. The results from the simulation demonstrate that the controller obtains a good performance of ride comfort with the less expense of the handling stability.

2 Dynamic characteristics of CVT hydraulic system in speed ratio changing

YANG Yang , WANG Xiaoping , QIN Datong , TANG Taofeng

2010, 33(4):9-13. DOI: 10.11835/j.issn.1000-582X.2010.04.002

[Abstract](1950) [HTML](0) [PDF 5.00 M](1380)

Abstract:
Aiming at the hydraulic system of CVT (Continuously Variable Transmission), the transfer function of hydraulic system of CVT and the dynamic simulation model of this system based on AMESIM are built, and the characteristics of speed ratio response is simulated and calculated. The influences of spring constant, damping coefficient and mass of moving part on rising time, setting time and overshoot are analyzed. The result shows that the dynamic simulation model of this system is reasonable and will provide a basis and method for the optimization of CVT hydraulic system’s dynamic characteristics in the future.

3 Objective evaluation methods of automobile riding comfort

ZHANG Zhifei , XU Zhongming , HE Yansong

2010, 33(4):14-20. DOI: 10.11835/j.issn.1000-582X.2010.04.003

[Abstract](3193) [HTML](0) [PDF 5.46 M](1723)

Abstract:
There is much difference between GB49701996 Method of random input running testAutomotive ride comfort and international evaluation methods, and the characters of automobile riding comfort is not discussed in detail. The measurement and evaluation methods are discussed. The tenaxis vibrations exposed to human body in automobile are measured throughout road testing, and then the characteristic of automobile riding comfort is analyzed. An objective measurement and evaluation method of automobile riding comfort are presented. The results show that the difference generated by frequency weighting factors ωk and ωb is very little. The crest factor of vibration in automobiles is about 4~8 by timedomain analysis. The percentage of each axis vibration is calculated, the results show that vertical vibration (zaxis) at seat surface, horizontal vibration (xaxis) at backrest and pitch vibration (rx axis) at seat surface are most important for comfort. The evaluation method in GB49701996 underestimates the vibration expose on the human body about 3 dB, which should be revised. Based on the results, a simple and convenient method for measuring vibration on automobiles is presented.

4 Realtime selflearning method of diagnostic knowledge in intelligent diagnosis system

SUN Hongyan , JIANG Xuefeng

2010, 33(4):21-25. DOI: 10.11835/j.issn.1000-582X.2010.04.004

[Abstract](2265) [HTML](0) [PDF 4.93 M](1143)

Abstract:
Aiming at realtime diagnostic knowledge accumulation and updating in intelligent diagnostic system, to simulate the process experts accumulate and update fault diagnostic knowledge, a new realtime diagnostic knowledge selflearning model is proposed based on pattern comparing and updating. Abnormal distribution test of hypothesis is used to compare realtime equipment fault pattern to equipment normal pattern of contingent knowledge. The algorithm of sample size estimation algorithm is used to calculate the number of samples which is used to obtain necessary diagnostic efficiency. Realtime model updating algorithm is used to adjust the diagnostic knowledge model to actual equipment on the spot. Analysis to actual test data of equipment shows that the method could achieve new diagnostic knowledge accumulation and be adaptive to actual equipment on the spot.

5 Prediction model on the radiated electromagnetic interference of wiper motor in automobile

WANG Quandi , LI Fei , ZHOU Shanghu , LIU Qingsong , WEI Xin , SI Haitao

2010, 33(4):26-30. DOI: 10.11835/j.issn.1000-582X.2010.04.005

[Abstract](2363) [HTML](0) [PDF 5.15 M](1683)

Abstract:
According to the theory of signals and systems, the radiated system’s transfer function is derived, the radiation electromagnetic interference(EMI) simulation model of the wiper motor based on the finite integration technique(FIT) algorithm is established, and the whole system’s transfer function are obtained in the environment of simulation software CST. The terminal voltage of the motor，as the noise source of radiation system, can be gained with experiment. The radiation electric field can be calculated by transfer function multiplying motor’s terminal voltage. Then the complex question of motor’s systemlevel radiation can be transformed to the simple problems of computing system’s transfer function and the motor’s terminal voltage. By comparing simulation and experiment results, it is showed that the radiated EMI simulation model of the motor can demonstrate the essential feature of motor’s electromagnetic radiation system accurately, which means that it can be used in the research of wiper motor EMC forecasting.

6 Hybrid multiobjective particle swarm optimization and estimation of distribution algorithm

LUO Ciyong , LU Bin , CHEN Minyou , ZHANG Congyu

2010, 33(4):31-36. DOI: 10.11835/j.issn.1000-582X.2010.04.006

[Abstract](2474) [HTML](0) [PDF 5.28 M](2314)

Abstract:
Multiobjective Particle Swarm Optimization & Estimation of Distribution Algorithm (MOPSO&EDA) is presented for solving multiobjective problem. During the process of optimization, half of offspring solutions are updated by the Particle Swarm Optimization (PSO) algorithm with mutation which has the ability of global search. Another half of offspring solutions are created by the Estimation of Distribution Algorithm (EDA) which has better ability of learning and local research. EDA explicitly extracts globally statistical information from the selected solutions and builds a posterior probability distribution model of promising solutions based on the extracted information. Compared with some other multiobjective algorithms, the Pareto Sets obtained by MOPSO&EDA have good convergence and diversity performance on ZDT1~ZDT3, ZDT6, ZDT61 instances, and the performance metrics of convergence and diversity on ZDT4 are moderate.

7 A new determination method of tool step for 5axis NC machining

JI Junfeng , ZHOU Laishui , AN Luling , ZHANG Chen

2010, 33(4):37-42. DOI: 10.11835/j.issn.1000-582X.2010.04.007

[Abstract](2246) [HTML](0) [PDF 5.54 M](1141)

Abstract:
The peculiar nonlinear error in the 5axis NC machining is studied. An improved tool step determination method for the 5axis NC machining is proposed, in which the nonlinear error is compensated. Both the arcchord error and the nonlinear error are considered when computing the tool step, and the comprehensive error is taken as the function of the tool path parameter. Due to the difficulty of gaining the derivative of this function and the tool step according to the prescribed tolerance, the secant method is improved to guarantee the real solution locating in the converging range which is adopted to compute the tool step. The implementing example shows that the proposed method can compensate the nonlinear error effectively with meeting the prescribed tolerance. The exact tool step can be gotten efficiently with the improved secant method.

8 Dynamic characteristics of absorbing SO2 by Ca(OH)2 liquid particles in Spray Drying Desulfurization Absorber

RAN Jingyu , DU Mengyi , RAN Jingwang

2010, 33(4):43-48. DOI: 10.11835/j.issn.1000-582X.2010.04.008

[Abstract](1775) [HTML](0) [PDF 6.27 M](1115)

Abstract:
This paper simulated SO2 concentration at three different CLP diameters based on the mathematic model of heat and mass transfer of Ca(OH)2 Liquid Particles (CLP)in Spray Drying Desulfurization Absorber(SDDA), the transient characteristics of water and solid weight in CLP, the temperature of CLP, the temperature of flue gas. The results show that while the CLP diameter, the temperature change rate of CLP and flue gas in crease, the mass increasing rate of CLP decrease. At the same time, the absorbing time to stable state of CLP becomes longer, the stable mass and the vaporizing rate of CLP increase. On the other hand, coupling simulation between the numerical and transient simulation process, the transient characteristics of absorbing SO2 for CLP are finished for CLP in SDDA at different flue gas temperature with CLP diameter 80 μm.With increasing the flue gas temperature, the mass increasing rate of CLP changes slowly, and the absorbing time to stable state of CLP also becomes longer. The SO2 absorbing efficiency increases, and its changing rate becomes fast.

9 Numerical simulation on multijet diffusion combustion of low concentration coal bed methane

TANG Qiang , LI Jianxiong , WANG Lipeng

2010, 33(4):49-53. DOI: 10.11835/j.issn.1000-582X.2010.04.009

[Abstract](1772) [HTML](0) [PDF 4.81 M](1105)

Abstract:
It is important to utilize coal bed methane to achieve the safe, environmental and economic benefits. The authors simulate the processes of multijet diffusion combustion of low concentration coal bed methane using kε turbulence model，nonpremixed combustion model and P1 radiation model. The influences of different geometrical structures and operating parameters on the combustion process are compared with each other. The results show that the distance between the gas nozzles and central axis，the angle of gas deflected from air ，the velocity ratio of air to gas have important impacts on the combustion. When the distance, the deflection angle and the velocity ratio are 30 mm，45 °and 2, respectively. The best combustion result can be achieved.

10 Investigations of the particle motion characteristics in the gassolid twophase wake of leeward side circular cylinder

LIU Hongtao , ZHANG Li , CHEN Yanrong

2010, 33(4):54-59. DOI: 10.11835/j.issn.1000-582X.2010.04.010

[Abstract](2369) [HTML](0) [PDF 6.95 M](1615)

Abstract:
This paper investigates the characteristics of the particle motion in circular cylinder wake flow of leeward side by simulating the microparticle flow around circular cylinder using Euler twofluid model combined with Reynolds stress model. It compares the particle velocity and concentration of different particle size in the leeward area. The results show that the vortex is formed after the gas flowed passing the cylinder, and the concentration and velocity of particles are affected by the turbulent intensity in the leeward side. Gas entrainment vortex and particles own inertia decide the flow form of fine particle around the cylinder. Both effects impact the particle concentration distribution of different size particles in the leeward area. With the increase of particle size, the particle concentration increases at the beginning and then decreases in the leeward area.

11 Numerical Simulation of Catalytic Combustion of Extremely Low Concentration CH4

PU Ge , LI Wenjun , yan yunfei

2010, 33(4):60-64. DOI: 10.11835/j.issn.1000-582X.2010.04.011

[Abstract](2079) [HTML](0) [PDF 4.28 M](1280)

Abstract:
This paper used FLUENT to simulate the Catalytic combustion characteristics of extremely low concentration methane in microchannel of honeycomb combustor which was coated with catalyst Pt/Al2O3.It analyzed the effect of inlet CH4 concentration, temperature of catalyst wall and inlet fuel velocity on CH4 conversion ratio. The results show that CH4 conversion rate is increases with the increase of inlet CH4 concentration and catalyst wall temperature and the decrease of inlet fuel velocity. When inlet fuel velocity is 0.1 m/s, CH4 volume concentration is 1%, catalyst wall temperature is 950 K, the conversion ratio of CH4 can achieve to 97.0%.

12 Molecular simulation of pyrolysis mechanism of cellulose and analysis of formation paths of major products

HUANG Jinbao , LIU Chao , WEI Shunan , FAN Xing , JIANG Dezheng

2010, 33(4):65-69. DOI: 10.11835/j.issn.1000-582X.2010.04.012

[Abstract](2451) [HTML](0) [PDF 4.58 M](1439)

Abstract:
Molecular dynamics simulation method, based on the force field, is an important and effective method to study the structure and performance of molecule. For the purpose of understanding of formation mechanism of major products from the thermal decomposition of cellulose，this paper investigates the pyrolysis mechanism of cellulose with 10 monomers by molecular dynamics simulation. The simulation results show that hydroxide radical is produced through COH bond scission at about 450 K; with the increase of temperature, at about 600 K cellulose monomer gets to be formed by glucoside bond rupture, at the same time, pyranoid ring is opened and all kinds of molecular fragment are formed. Based on the other experimental results of references, the possible formation paths of major products through reaction of all kinds of molecular fragment are analyzed.

13 Nonlinear numerical simulation of steel reinforced concrete truss joints

YUAN Zhengqiang , XIANG Hao , LI Baoming , ZHOU Hongwen

2010, 33(4):70-74. DOI: 10.11835/j.issn.1000-582X.2010.04.013

[Abstract](1866) [HTML](0) [PDF 7.41 M](1327)

Abstract:
This paper analyzes the steel reinforced concrete large span transfer truss joints using the finite element analysis software ANSYS, and get the joints deformation and the mechanics increase, such as deformation properties, stress distribution. The monitoring results during construction phase show that nonlinear numerical simulation analysis, which is in good agreement with the test results, is an effective method for the mechanical property analysis on this kind of structural components.

14 Constitutive model for soils based on the concept of disturbing structure

ZHENG Zhineng , ZHANG Yongxin , LIU Yuanxue , Ling Tianqing

2010, 33(4):75-79. DOI: 10.11835/j.issn.1000-582X.2010.04.014

[Abstract](2016) [HTML](0) [PDF 4.40 M](1374)

Abstract:
Based on the concept of disturbing structure, this paper presents a progressive yield constitutive model by extending the CamClay model in order to describe influence of the disturbing structure on soil behavior. The internal variable of yield surface is not just a constant parameter, and it should be treated as a distribution function in a range. The single yield surface of the CamClay model wis extended to a field of yield surface. Then by introducing the progressive yield concept into the CamClay model, the progressive yield constitutive model wis developed. Only one parameter wis added besides the three parameters of the CamClay, which represents the disturbing structure of the soils. The application results show that the model can predict the progressive yield of the soils.

15 Application of horizontal drain holes in the engineeringcontrol of bank slope

TAND Xiansong , ZHENG Yingren , Liu Liang , Liang Yu

2010, 33(4):80-87. DOI: 10.11835/j.issn.1000-582X.2010.04.015

[Abstract](1891) [HTML](0) [PDF 6.48 M](1348)

Abstract:
Since the analysis of seepage field with horizontal drain holes and the stability analysis of reservoir banks are very complicated, the application of horizontal drain holes in the engineering control of bank slope is restricted seriously. It is economical and reasonable to add horizontal drain holes to improve the slope stability, so it is of both practical and theoretical significance to research horizontal drain holes. Considering the complication of analysis, the paper introduces a complete set of methods of establishing the model of horizontal drain holes, analyzing the seepage field with horizontal drain holes and analyzing the slope stability after engineering control with horizontal drain holes only in twodimensional condition with a calculation example. The results of numerical analysis show that the slope stability can be improved by adding horizontal drain holes. and the length of the hole has obvious effects on draining compared with the aperture.

16 Improved WPAN meshed adaptive tree routing algorithm

JIANG Yusheng , HE fang

2010, 33(4):88-91. DOI: 10.11835/j.issn.1000-582X.2010.04.016

[Abstract](1766) [HTML](0) [PDF 4.48 M](1121)

Abstract:
To expand network coverage and enhance the reliability of wireless personal area network (WPAN), the problem of address overflow resulting from applying the meshed adaptive tree algorithm in largescale mesh network wis studied. By dividing the entire network into smaller subnetworks, the subarea meshed adaptive tree wis constructed. An improved meshed adaptive tree routing algorithm wis proposed employing the hierarchical topology structure of the subarea meshed adaptive tree. Experimental results show that the algorithm expands the network coverage without increasing the routing overhead and the network load. It also effectively reduces the endtoend delay and increases the packet delivery ratio and communication efficiency. It maintains a good performance in the networks with different scales and provides a theoretical basis for enhancing the coverage and reliability of WPAN.

17 Segmentation algorithm for urinary sediment image combiningwavelet transform and 2DMaximum entropy threshold

YIN Yong , Zhao Shaomin

2010, 33(4):92-97. DOI: 10.11835/j.issn.1000-582X.2010.04.017

[Abstract](2739) [HTML](0) [PDF 5.53 M](1407)

Abstract:
In order to solve the problem that urine sediment visible components cannot be segmented effectively because of complex components, complicated defocusing in image and poor discrimination between object and background, a method based on combination algorithm wis designed to segment urine sediment. The wavelet transform wis used to erase the effect of defocusing. Then morphology wis utilized to get the subimages that include the particles. The segmentation method combining the wavelet transform based segmentation and the twodimensional entropy threshold based segmentation wis employed to segment urine sediment visible components. Experimental results show that the proposed method can segment urinary sediment images effectively and precisely.

18 Adaptive window smoothing method for 4f system imagesin wavelet domain

Xu Xin , Han Liang , Ji Yanli

2010, 33(4):98-104. DOI: 10.11835/j.issn.1000-582X.2010.04.018

[Abstract](1727) [HTML](0) [PDF 7.39 M](1225)

Abstract:
Due to the features of limited frequency band and existing noise for the output images of the conventional 4f information optics system, it is required to protect the image detail regions much better when restoring the images. Based on the classic AWM method, an adaptive window smoothing method which can adaptively adjust the shape of the smoothing window in wavelet domain is proposed to remove the random noise in the system output images. The method utilizes the direction of the high pass subimages decomposed by wavelets to determine the direction of the smoothing window, and adjusts the size of the smoothing window based on the advantage of energy concentration characteristics of subimages in wavelet domain to adjust the shape of the window adaptively. The output image of the 4f system is smoothed with the adjusted windows. The theoretical analysis and experiments show that the method can denoise the image in visual sensation and protect the image detail well, while PSNR is improved about 2 dB. It is suitable for the cases which require a certain image precision and has low pass characters, such as the 4f optic system.

19 A blind channel estimation algorithm for UltraWideband channel based on compressive sensing

LIU Yulin , ZHANG Xianyu , HE Jiwei , XU duo

2010, 33(4):105-108. DOI: 10.11835/j.issn.1000-582X.2010.04.019

[Abstract](2539) [HTML](0) [PDF 3.83 M](1580)

Abstract:
The sampling speed for the ultra wideband (UWB) channel is too high to realize with the existing sampling technology. To solve the problem, a novel blind channel estimation algorithm was presented based on the theory of compressive sensing. Firstly, some measurements are obtained which are linear combinations of the received signals multiplied by a random incoherent measurement matrix. Then, the mathematical model is established by exploiting the first statistics of the measurements. Finally, the orthogonal matching pursuit (OMP) algorithm is utilized to get the estimating channel parameters. With the proposed algorithm, the number of the measurements need for channel estimation is much smaller than that of the samples needed for the existing algorithms, which reduces the ADC resources greatly. The simulation result shows that the estimation performance of the algorithm is good, while the bit error rate (BER) is only 2~3dB higher than that of the exact channel.

20 Design and FPGA Implementation of animproved structure of digital matched filter

Tan Xiaoheng , Yang Lili , Zhang Mao

2010, 33(4):109-114. DOI: 10.11835/j.issn.1000-582X.2010.04.020

[Abstract](2371) [HTML](0) [PDF 5.11 M](1369)

Abstract:
An improved structure of digital matched filter(DMF)is presented. Two same pseudorandom spreadspectrum sequences with the length of N are used to spread the same baseband symbol at the transmitter, which is equal to spread the baseband symbol with a spreadspectrum sequence with the length of 2N. At the receiver, only a spreadspectrum sequence with the length of N is needed to de spread the data, and then cumulates the two correlation peaks and exports to the output. The detection probability(Pd)and the false alarm probability(Pf)are analyzed and simulated. The improved structure of DMF is implemented based on the recursive and folded principle. Experimental results show that, for the same spread gain, the improved structure has the same Pd and Pf as the basic DMF, while saves the hardware resources greatly compared with the recursive and folded structure.

21 Design method of generatingDICOM Image in the high frequency X ray machine

Zhang SiJie , Chen zhenhua , Zeng XiaoPing , Guo Xingming

2010, 33(4):115-119. DOI: 10.11835/j.issn.1000-582X.2010.04.021

[Abstract](2198) [HTML](0) [PDF 4.00 M](1113)

Abstract:
DICOM3.0 standard is complex and rich in contents. Aiming at the difficulty of software design, a programming method of generating DICOM image file in the high frequency X ray machine is proposed. The data structure of DICOM file is analyzed, and then the programming method of generating DICOM image files is introduced in detail. For the proposed method, a template array of the data structure is constructed to save the eigenvalues, transfer syntax, pixel data and so on of the image. All kinds of the data are stored in the DICOM file successively. The programming method can not only transform a BMP file into a DICOM file, but also transform a JPEG file into a DICOM file. It strictly follows DICOM 3.0 protocol. The generated DICOM files can be displayed with the DICOM file browsing software ezDICOM. The programming design was based on VC++6.0.

22 Application of improved meanshiftalgorithm in rocket target tracking

YIN Hongpeng , CHAI Yib , WEI Hongbo , GUO Maoyun

2010, 33(4):120-126. DOI: 10.11835/j.issn.1000-582X.2010.04.022

[Abstract](2443) [HTML](0) [PDF 5.97 M](1280)

Abstract:
An improved Meanshiftbased rocket target tracking algorithm is presented. The traditional Meanshift tracker is difficult in tracking fast moving rocket target and suffers in cumulating error. To overcome the limitation of the traditional Meanshift tracking algorithm, threeframedifference method is employed to detect the rough position of rocket target. Based on the rough position, Meanshift algorithm is used to achieve precise tracking. Simulation experiments show that the proposed algorithm can effectively track fast moving rocket target and overcome the tracking error cumulating problems.

23 Multichannel cortical stimulator based on FPGA

PENG Chenglin , CAI Chunming , HOU Wensheng , ZHEN Xiaolin , YIN Zhengqin , WU Xiaoying

2010, 33(4):127-132. DOI: 10.11835/j.issn.1000-582X.2010.04.023

[Abstract](2455) [HTML](0) [PDF 5.53 M](1436)

Abstract:
A FPGA based multichannel cortical stimulator system for cortical visual prosthesis was designed. devised for generating a sequence of electrical pulses for cortical stimulation. The simulator is composed of a FPGA and voltage/current converters. The FPGA comprises a spike generator to generate various electrical pulse sequences and some multiplexers to select signals. The prototype based on an Altera Cyclone EP1C6 FPGA with four channels is developed to perform the experimental evaluation. Two electrode chips ane put out of the left and right dura of cortex of a cat. The electrical stimulation is connected to the left one, while the visual electrically evoked potential (EEP) is recorded by the right one. The experimental results on cat's cortex show that the cortex can respond to the current stimulation.

Home

Volume 33,Issue 4,2010 Table of Contents

Current Issue

Volume

Issue

Most Read

Most Cited

Most Downloaded