Table of Content

25 August 2009, Volume 20 Issue 16

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Study and Application of a Novel Bi-spring-blade Based Connection Mechanism


Yang Dehua;Jiang Fanghua;Zhou Guohua;Chen Kunxin

2009, 20(16):  0-1895. 

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Based on bi-spring-blade concept,a novel flexible connection mechnism was put forward with detailed analyses of degree-of-
freedom(DOF) and stiffness.Taking advantage of the nature of thin spring blade characterized by perfect out-plane flexibility and in-plane stiffness,the flexible connection
realized direction-independent stiffnesses and allowed the connected body to have 3 DOFs without backlash and hysteresis.The connection is especially well suited for the connected body that is to vary poses or vibrate/sway during operation.Also,it is to be used to eliminate relative rotation of
two bodies with allowed relative precision movements or to be used as coupling mechnism to sychronize rotation of two shafts.The successful application of the novel connection mechanism to precision movements of an optical mirror system introduced an significant stiffness increment,from 3Hz to 9Hz,of the rotary eigenfrequency,meanwhile,
it realizes backlash-free and hysteresis-free motion with 3DOFs at resolution of
10nm class required by the movements of the mirror system.

Three-step Calibration for Binocular Stereo System

Zhang Hui;Zhang Liyan;Wei Hu

2009, 20(16):  0-2015. 

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A practical 3-step binocular camera calibration method was proposed herein.Firstly,assuming pin-hole model,the internal and external parameters’ initial values were estimated by using projective transformation principles.Secondly,
the parameters were optimized by LM nonlinear optimization algorithm taking last step’s results as initial values and targeting at minimizing re-projection errors.Thirdly and lastly,another LM optimization was conducted adding plate’s feature 3D
coordinates as optimization parameters,afterwards real metrics were obtained by scaling.
Compared to traditional 2-step calibration, instead of strictly assuming calibration object’s 3D precision,this method takes great advantages of nonlinear optimization
algorithm to get real features’3D coordinates,thus eliminating the infection of errors of 3D features on calibration.The validity and efficiency of our method can be demonstrated by the results of post-calibration 3D reconstruction experiments.

Study on Driving Characteristics of a Variable Load Wall Climbing Robot 

Wang Xingru;Yi Zhengyao;Gong Yongjun;Wang Zuwen

2009, 20(16):  0-1895. 

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A wall climbing robot for removal rust in vessels was designed,and the robot structure and working principle were introduced.Through comprehensive
analysis on the weight of pipeline load and the center of gravity position,the driving mechanical models that the robot climbing and turning on the vessel wall were established,and the models were optimized.The climbing driving torque equation was obtained by considering the change of the weight of pipeline load and the center of gravity position.According to climbing driving torque equation,the driving system was analyzed by simulation.Finally,the result shows that the optimized model is reliable,and the permanent magnet adsorption force,vacuum suction force,water jet force,number of permanent magnet,and in practical work,the safety height is over 30 meter with the vessel wall is approximately vertical.

Face Tracking for Elderly Companion Robot Using Camshift Algorithm and Particle Filter

Tao Yong;Wang Tianmiao;Wei Hongxing;Chen Diansheng

2009, 20(16):  0-2015. 

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A real-time face tracking method for the elderly companion robot was presented based on the Camshift algorithm and particle filter algorithm. Camshift algorithm was applied to find the peak of probability distributions and to estimate the center and size of the tracking window. According to the complexity of the house environment and the features of face tracking’s non-Gaussian non-linear, the particle filter was used to estimate the movement tendency and to improve the accuracy and the ability of
anti-interference. Experimental results show that the proposed method can track face robustly in the indoor environment, which illustrates the real time and efficiency.

Experimental Study on Dynamics Characteristics of Moving-magnet Linear Compressor

Chen Xi;Zhang Hua;Chen Nan;Wu Yinong

2009, 20(16):  0-1895. 

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A prototype of moving magnet linear compressor had been manufactured successfully.In order to study the prototype,a performance test bench was built.By means of varying the operation and geometry parameters of linear compressor including working frequency,voltage,current,charging pressure,mass of piston and clearance,the overall performance of linear compressor had been obtained. It is found that light piston,high charging pressure and high working frequency will bring large output power;optimal working frequency should be at the range of 85%~90% natural frequency.
The clearness seal can effect on compressor natural frequency,and the leakage of clearness seal is direct ratio to pressure wave in compression chamber. 

Research on Fuzzy Fault Tree Analysis Method for Hydraulic System Based on T-S Model

Yao Chengyu;Zhao Jingyi

2009, 20(16):  0-2015. 

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In order to solve the three disadvantages of insufficient fault probabilities and difficulties to determine events’ relationships and describe fault degrees during fault tree analysis on hydraulic systems, T-S model was presented to fuzzy fault tree analysis, where fault probabilities were described as fuzzy possibilities; and events’ relationships were described by T-S gates instead of conventional logic gates; then fault degrees were described as fuzzy numbers.Example of fault tree analysis of oil supply system of hydraulic press was given for illustration, where fuzzy fault possibilities of top event and fault degrees are achieved.

Study on Contact Stress Distribution of Roller 
Bearings and Roller Profile Design under Misaligned Loads

Mao Yuexin;Shen Xuejin;Chen Xiaoyang;Pan Guoliang

2009, 20(16):  0-1895. 

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Based on elastic-contact theory,the relationship of
surface functions,elastic approach and contact stress on each point of roller and ring’s surface were analyzed under misaligned loads herein.The effect coefficient method which was used to disperse the function of elastic approach,the moment and load equation
was introduced,and a program compiled by FORTRAN was used to solve the contact problem.Contact stress distributions between roller and ring were calculated with this program,and they were proved through comparing with the data of disk experiment which had been done by Kannel.The authors also analyzed how contact pressure distributions transform with different tilting quantities,roller loads,roller ratio between length and diameter and crown line profile.It shows:the “edge effect” of contact stress reduces but the maximum pressure reduces first and then increases when increasing the roller crown.A method of bearing profile design was carried out according to the phenomena.By using this method, roller bearing can resist misalignment and the maximum contact stress is reduced more effectively.

Environmental Impact Evaluation Model of Manufacturing Processes Based on BP

Neural Network

2009, 20(16):  0-2015. 

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An effort was made to propose a synthetic evaluation method based on the BP neural network and establish an environmental evaluation model of manufacture process to guarantee the evaluation results more objectively.An instance of environmental assessment of gear manufacturing was taken to illustrate how to set up such kind of evaluation model after developing the evaluation indicator system.And the simulation results of the evaluation model were verified by using the neural network tool of MATLAB.

Research on Fault Model Technology in Testability Simulation-based Fault Injection
Experiment


Li Tianmei;Qiu Jing;Liu Guanjun

2009, 20(16):  0-1895. 

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The low validity and precision of fault model make the phenomena of fault latency occur frequently in testability simulation-based fault injection
experiments.So a fault model based on Bayesian networks and object-oriented technology which was used in fault injection experiments was founded.Firstly,the mechanism of testability demonstration experiment was introduced,then,put forward the principle of fault model in fault injection experiment and founded a seven-members fault model.The fault behavior condition vector could be received by Bayesian positive consequence,the relative fault
vector could be received by Bayesian negative consequence.At the same time,Bayesian
consequence algorithm could validate the validity and precision of fault model.Finally,
an example shows that the validity of fault injection based on this fault model is 100% and can avoid assembled explode phenomena.

Stability Evaluation of Instantaneous Rotational Speed for Internal
Combustion Engine via Detrended Fluctuation Analysis


Hu Chongqing;Li Aihua;Zhu Chunhong;Guo Mingfang

2009, 20(16):  0-2015. 

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The effect of periodic trends on the detrended fluctuation analysis was discussed.The spectrum of the trend determined the number and locations of crossovers.For the instantaneous angular speed of an
internal combustion engine,crossovers revealed the regularity of its fluctuation.
The stability of the instantaneous angular speed was evaluated by its periodicity and its consistency with the mean speed.Experimental results from implementation on a 6135 diesel engine confirm the performance of the proposed method.

Research on No-wait Flowshop Scheduling Problem Based on Combination Variable Neighborhood Search

Wang Jing,;Li Tieke;Zhang Wenxue

2009, 20(16):  0-1895. 

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This paper presented a hybrid algorithm for no-wait flowshop scheduling problem with makespan criterion.The algorithm included three stages.In the first stage,the problem was changed to TSP,and constructed the expenses matrix according the characteristics of the problem,but the expenses matrix was solved as an assign problem; then an initial solution was got in the second stage; and in the third stage the current
solution was optimized using the combination variable neighborhood search.The proposed algorithms are evaluated and found to be relatively more effective in finding better quality solutions than that from existing algorithms.

Predictable Robust Scheduling under Uncertainty-a Multi-Agent Based Approach

Chen Yu,;Chen Xin;Chen Xindu

2009, 20(16):  0-2015. 

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Uncertainty events and their influences in a real manufacturing situation are a complex stochastic phenomenon, and it is very difficult to build accurate formulations used in addressing the scheduling problem and in solution processes.Some issues
related to executing production schedules in the presence of unforeseen disruptions
in the job shop were discussed, the interrelationship among uncertainties and equipment effectiveness was deduced, and a novel robust approach to solve the predictable
scheduling problem based on overall equipment effectiveness(OEE) was presented.An agent-based framework used for predictable scheduling system was also proposed.Finally,the simulation results illustrate that the proposed approach is effective in reducing the delay of operation and in enhancing the stability of scheduling.

Study on Complex Product Assembly Executive Process Modeling and Monitoring Method

Sun Huibin;Chang Zhiyong 

2009, 20(16):  0-1895. 

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To solve the asynchrony problem between the logistics stream and the information stream in complex product assembly executive process, an assembly executive process Petri net (AEPPN) model was proposed. States of assembly and logistics were described by transitions. Events in the assembly executive process were described by places. They were implemented via logistics agent, assembly

Agent and RFID tags’ state respectively. The example verifies that, the study can improve the real-time property and veracity of the assembly executive process online monitoring and controlling, as well as enhance the feasibility of off-line monitoring and control.

Dynamics Simulation of Planetary Gear Train Based on MFBD Technology

Ma Xingguo,;Lu Yang;You Xiaomei,

2009, 20(16):  0-2015. 

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Based on MFBD technology,a rigid-flexible coupling module of planetary gear train was created and the flexible parts used two modeling methods of nodal approach and modal reduction.The flexible multi-body systems were simulated and analyzed by using RecurDyn software, the curves of rotational speed of planet carrier and the dynamic meshing forces of gears were also obtained. The results were compared with the analysis ones of rigid body system.Synchronously,the stress nephogram and the curves of node stress of the planetary gear train are obtained in meshing process.The main break reasons of the planetary gear are obtained by analyzing the results of simulation.And simulation data offers the basis for design optimization and fatigue properties study, which provides effective means for the development of new products.

Unstructured Surface Mesh Generation for Topography Using Interpolating Surface Modelling

Deng Zhiping;Wang Yu

2009, 20(16):  0-1895. 

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We combined interpolating surface modelling with the traditional Delaunay triangulation algorithm to design a new surface mesh generation scheme. Using this scheme the disadvantages of the traditional analytical model on the discontinuous surface modelling can be avoided and the underlying geometric model from random scattered measurements can be established. The application results show that it produces a good mesh shape. The ability to deal with the sharp changes also is very good. All of these characteristics make this scheme have a great potential application in finite element analysis in geological area.

Fine Classification Method of Mechanical and Electrical Equipment Selection Design

Li Guangming，;Yin Guofu;Yao Xiaopeng

2009, 20(16):  0-2015. 

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In view of fuzzy,complexity in some extents was present in the process of design of the mechanical and electrical products in selection.
In order to improve the design process and the efficiency and quality of retrieval, a method of mixing various techniques and traditional fuzzy C-means clustering together
was proposed.On the basis of fuzzy C-means theory,the improved clustering model can get more appropriate data for design,reasoning and retrieve data quality and can avoid the blindness of classification and man-made subjective factors in a certain extent by introducing the optimum ratio of pseudo statistics. Finally, an example was provided to prove the method efficiency and feasibility.

Application of Finite Element Analysis for Structural Design of Magnetoelastic Transducer

Jia Zhenyuan;Lu Xiaohong;Wang Fuji;Liu Wei 

2009, 20(16):  0-1895. 

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There exists a great difference between the existing structural model of Permalloy magnetoelastic force transducers and the actual situation. For precise and quantitative analysis and research on the magnetoelastic effect of Permalloy, a representative model that regarded the Permalloy sensor as a two dimensional Permalloy plane unit was proposed, which reduced the difficulty for solving the problem. The ratio of stress to area was used as the appraisal and estimation criterion of the different structural model of the sensor. Finite element analysis software SSAP93 was utilized to calculate and analyze the different structures of the studied sensor comparatively. The ultimate results of the finite element analysis determine the structure and size of the Permalloy magnetoelastic force transducer.

Nonlinear Dynamics Analysis of Electromechanical Coupled Micro-plate

Sun Libo;Xu Lizhong

2009, 20(16):  0-2015. 

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Based on the minor deflection bending theory of elastic thin-slab,using Lindstedt-Poincaré method,the satisfied conclusion was obtained.In example analysis,the micro-pump membrane was as the research object.The results show that the nonlinear analytical method has higher precision;the solution increases the systemic design rationality,and improves design precision.

Deployable Tetrahedral Truss Antenna Initial Structural Design 
Based on Interpretative Structural Model Analysis

Yang Yulong;Guan Fuling;Hou Guoyong;Zhang Jingjie 

2009, 20(16):  0-1895. 

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In order to make the initial structural design process of deployable truss antenna to become simple and efficient,an interpretative structural modeling method of systems engineering was used.Key structural design targets and structural components were as elements in systems engineering and interpretative structural model of
systems engineering was built on the basis of the logical connections among all elements.Mutual relations were analyzed and the multilevel hierarchy structure of structural design process was obtained.So state equations about design targets and structural
components were found and structural component design was completed.A deployable tetrahedral truss paraboloid was designed and a 1∶1 scaled model was built to verify the design process.

3-D Flow Analysis of Oil Channel in Wet Multi-disc Friction Clutch

Lü Hesheng,;Lin Tengjiao;Zhang Shijun;Li Runfang

2009, 20(16):  0-2015. 

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Based on governing equations of incompressible fluid and the RNG k-ε turbulence hydrodynamic model, 3-D fluid models of oil flow channel of two similar structures were established. Using finite element method, the flow field was analyzed by the software of ANSYS/FLOTRAN CFD, and then the influence of different structure of oil flow channel on oil pressure between the friction pieces was discussed. The results show that the oil flow channel structure has a significant effect on the distribution of oil pressure and velocity. The second structure of oil flow channel based on the fisrt structure runs through four oil holes of right end. Compare two structures, and the oil pressure of the second structure is more uniform than the first as well as the value of velocity fluctuation is improved.

Evaluation Algorithm of Cylindricity Error Based on Coordinate Transformation

Li Jishun,;Lei Xianqing;Xue Yujun;Duan Mingde 

2009, 20(16):  0-1895. 

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A new method of evaluating cylindricity error based on coordinate conversion was proposed. The measured cylinder can be randomly placed,
sampling points in rectangular spatial coordinates and all discrete data can be sampled optionally,and the minimum zone cylinder(MZC),the minimum circumscribed cylinder(MCC) and the maximum inscribed cylinder(MIC) errors can be evaluated simultaneously in the error evaluation method.The process of using the algorithm to solve the cylindricity error was described in detail and the mathematical formula and program flowchart were given.
The experimental results show that the cylindricity error can be evaluated effectually and accurately using this algorithm. 

Vehicle Stability Control Method after Tire Blow-out

Ｈuang Jiang;Guo Konghui,;Song Xiaolin;Liu Wei

2009, 20(16):  0-2015. 

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Based on the results of tire experiments, the vehicle’s kinetic behavior after tire blow-out was analyzed.A differential brake method was set up to control vehicle behavior after tire blow-out.Furthermore,loading usual vehicle stability control method with references,the method of holding vehicle stability after tire blow-out was researched,which fully considered many factors,such as the changes of vehicle’s kinetic characteristics after tire blow-out,the impact force when the tire blows out.Tire was unseated from the rim and reasonable speed control,which can effectively maintain the stability of vehicle.
The method’s effect is validated through simulation study by CarSim software,
which provides the foundation for studying control system of vehicle after tire blow-out.

Numerical Simulation and Experiments on Bending Vibration Characteristics of Circular Piezoelectric Vibrator

Peng Taijiang;Kan Junwu;Yang Zhigang;Cheng Guangming

2009, 20(16):  0-1895. 

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The bending flexure curve equation of circular piezoelectric
vibrator was investigated according to deformation principle of elastic sheet so as to calculate its deflection exactly.Based on the flexure curve equation,numerical analysis about
the relationships among structural parameters,material characteristics and amplitude
was carried out,and the way to enhance amplitude of the vibrator was found out.Finally,experiments about quasi static amplitude and frequency-amplitude characteristics of different size vibrators were carried out to testify these relationships.According to the results
from analyses and experiments,means such as increasing actuate voltage and diameter ratio of ceramic and substrate can enhance the amplitude of the vibrator.As ceramic and substrate
thickness ratio of 0.8,the amplitude comes to maximum;to ensure that of the bond strength, the thinner of the glue layer,and the greater of the amplitude of the vibrator.The
resonant amplitude and quasi static amplitude is about 5%~10% and 50%~60% of the static deformation respectively.

Study on Plane Sweeping Flow Erosion Wear of UHMWPE/Nano-SiO2 Elastic Composite Materials

Guo;Yuanjun;He;Jianxiong;Xiao;Hualin;Hu;Binliang;Hu;Hui;

2009, 20(16):  0-2015. 

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Nanocomposites of UHMWPE/SiO2 were prepared by filling nano-SiO2 in UHMWPE (Ultra-high molecular weight polyethylene ).The effects of SiO2 contents in composite,sand concentration,velocity of sweeping flow and particle size on the erosion property of UHMWPE/SiO2 were studied by using the rotating disk erosion instrument.The erosion property of UHMWPE/SiO2 was compared with the pure UHMWPE and 45 steel.The worn surface of UHMWPE composite was examined with the scanning electron microscope(SEM) and the wear mechanism was discussed.It is found that when the content of SiO2 reaches 10%,the erosion rate of composite reaches the minimum;the erosion rate of composite increases with the increase of sand content,however,when the sand content reaches about 0.96kg/m3,the increase tend starts to become slow.The relationship between the impact speed and the erosion rate is a power function,when the content of SiO2 reaches 10%,the power of composites is 1.87;the erosion rate of composites increases with the increase of the particle size;when the content of SiO2 reaches 10%,compared with UHMWPE,the erosion rate of composites decreases by 30% and reaches one of sixteen of 45 steel.The important wear mechanism of plane sweeping
flow erosion is extyuding deformation and ploughing-cutting and fracture of lip tablets for UHMWPE/SiO2 elastic composite materials.

Simplified FEM Modeling Method for Simulating Side Impact Based on Vehicle Side Structure

Wu Guang;Li Guangyao;Chen Tao;Gao Hui 

2009, 20(16):  0-1895. 

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The process and criteria of side impact were analyzed.A new method based on vehicle side structure was presented to subordinate the time-consuming full-scale FEM model.Compared with the full-scale FEM model,which was validated by CNCAP side impact test, the simplified FEM model was proved to be effective and, at the same time,did not forfeit too much precision.Those boundary conditions extracted from the full-scale models were almost identical. Through applying this new method to safety design, it is demonstrated to be applicable and help to improve calculation efficiency. 

Research on LS-SVM Control of Automobile Anti-lock Braking System

Zheng Taixiong;Li Rui;Jiang Guoying;Yang yong

2009, 20(16):  0-2015. 

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In order to advance the intelligence of ABS, an automobile anti-lock braking control method based on LS-SVM was proposed.On the basis of experimental data analyses, the vehicle velocity estimation method using the slope of peak value of wheel velocity, then the reference slip rate was calculated. Based on analyzing the vehicle model, the road identifying method according to the vehicle deceleration, and then the adaptability of the control method was advanced. Using the reference slip rate and angle acceleration of the wheel as inputs and the control signal as output,a LS-SVM anti-lock braking control system, with road adaptability, was designed. Training the control system using supporting vector, the parameters of the control system were got, then the LS-SVM control was realized. The road tests under different conditions were completed according to the Chinese standards. Test results show that the proposed method has the characteristic of good braking stability and adaptability.

Optimization Design of Double Front Axle Steering Swing Arm Mechanism in Heavy-duty Trucks

Gu Yufeng;Fang Zongde;Shen Yunbo

2009, 20(16):  0-1895. 

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Multiple objective optimizing model was advanced because of the shortages of traditional single objective optimization method of double front axle steering swing arm mechanism in heavy-duty trucks,which integrated the rotation error minimization model of the left wheel in second axle with the minimization model of steering linkage and suspension system and
the non-uniform steering force minimization model.The wheel rotation error model was derived from the split swing arm mechanism,and the movement model of steering linkage and suspension system was derived from space motion model of steering drag link and suspension system,and the non-uniform steering force model was derived from the drive ratio of the steering drive mechanism.The optimization results show that multiple objective optimization method obtains the better results than that from the traditional optimization
method,and it is advantageous to reduce the abrasion of steering wheels,and improve the automobile controllability and stability and steering handiness.