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Table of Content

    25 July 2009, Volume 20 Issue 14
    Design and Kinematics Analysis of a Novel Robot Shoulder Joint
    Jin Zhenlin;Cao Shun;Gao Feng
    2009, 20(14):  0-16391642. 
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    Based on the orthogonal 3RRR spherical parallel mechanism,
    an unique shoulder joint of humanoid robot with parallel architecture was investigated,
    and the layout feature of the shoulder joint was described.The inverse kinematics equations and Jacobian matrix were given by the relation of geometry.Condition number which
    was detrude by Jacobian matrix was used to define dexterity measurement.According to restriction terms of workspace the constant orientation workspace and dexterity
    measurement were plotted.The results of analyses indicate that the shoulder joint enjoys many advantages over its compact structure, good decoupled property,easy manufacturing and assemble.It shows good performance as a shoulder joint of humanoid robot.

    A Novel Linear Approach for Camera Calibration Based on Parallel Mechanism
    Zhang Shihui;Guo Cuicui;Kong Lingfu
    2009, 20(14):  0-16391642. 
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    A novel linear approach for camera calibration based on parallel mechanism was proposed. First, the integrated expression of camera model with the first-order radial distortion was educed. Then a virtual 3D target was constructed by using the motion platform of the 6-DOF parallel mechanism as the carrier of 2D planar template. After the first-order radial distortion parameter and the principal point coordinates were solved, the other parameters were computed linearly using the foregoing camera model and the information of virtual 3D target.This approach can make the calibration state consistent with the work state,it eliminates 3D target’s facture and the instability of nonlinear optimization.Experiments with simulated data as well as real image show that the approach is feasible and efficient.

    Arc Spline Tool Path Generation for Triangular Mesh Surface Machining 
    Chen Xiaobing,;Liao Wenhe
    2009, 20(14):  0-1699. 
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    An approach to generate arc spline tool path of triangular mesh
    surface was proposed.CL(cutter location) points of interference-free line tool path were obtained by intersecting offset surface of triangular mesh surface with a series of parallel drive surfaces of variable path interval, and these points were classified into three categories and the redundant points of each category were removed with the least square fitting separately,then the fitting precision of CL points was revised by mapping tool path deviation into fitting
    deviation.After transition process of line-arc tool path, the developed arc spline tool path holds G1 continuity and high precision. Experimental result indicates that the presented approach is effective.

    Two-dimension Modelling for Material Removal of Magneto-rheological Finishing
    Chen Fengjun;Yin Shaohui;Zhu Kejun;Ohmori Hitoshi;Zhu Yongjian;Fan Yufeng
    2009, 20(14):  0-16391642. 
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    According to the rheological characteristics of
    magneto-rheological fluid in the magnetic field,the Preston equation,the Reynolds equation and its boundary conditions were extended based on fluid kinematical theory.The pressure model and the material removal model in two-dimensional directions were built and analyzed.Finally,the basis experiments of MRF were carried out,and the influences of the immersed depth and material types were studied.The experimental data were compared
    with the simulation results of material removal model,which confirms validity of the model.

    Chaotic Characteristic Analysis on Dynamic Properties of NC Table
    Wang Linhong,;Wu Bo;Du Runsheng;Yang Shuzi
    2009, 20(14):  0-1699. 
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    By means of the theory and method on phase-space reconstruction,correlation dimension and maximum Lyapunov exponent from chaos theory, dynamic time series measured from NC table were analyzed.The characteristic quantities as power spectrum,phase trajectories,correlation dimension and maximum Lyapunov exponent
    etc. were extracted.The chaotic characteristic of dynamic properties of NC table was revealed with several approaches.The conclusion that NC table is a nonlinear dynamic system can be drawn.This research represents basis for the dynamic system identification of CNC machine.

    Dead-center Positions of Six-bar Linkages Based on Instant Centers
    Guo Xiaoning;Zou Yanhuo;Dou Ning 
    2009, 20(14):  0-16391642. 
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    Based on the relation of mechanical efficiency and instantaneous centers,the necessary geometric conditions for the instantaneous centers of a linkage when it was in dead-center positions were given.This methodology avoids the handling of complicated algebraic equation and remains valid for the mechanisms with prismatic joints provided instantaneous centers can be located.Based on the method possible configurations of the six-bar linkage in dead-center positions were listed,and this method presents a way for the problem of whether a crank exists in a mechanism.

    Experimental Study on Milling Forces in High-speed End Milling of LF21 Aluminum Alloy
    Wang Zhenhua;Yuan Juntang;Hu Xiaoqiu;Huang Jianan
    2009, 20(14):  0-1699. 
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    Using 4mm diameter straight end mill H10F,uncoated carbide
    tool,the effect of cutting parameters on milling force was analyzed by the one-way and multi-way experiments of milling forces in high speed machining of LF21 which were carried out with spindle speeds from 8 to 40kr/min,feed per tooth from 0.03 to 0.07mm and depth of cut from 0.5 to 2.5mm.The correlation coefficient was used to analyze the effect of cutting parameters on component force (Fx,Fy,Fz).The approach for machining weak rigidity workpieces was presented.

    Study on Borosilicate Glass Sheet Reverse Bending with CO2 Laser
    Wu Dongjiang;Niu Fangyong;Zhang Qiang;Guo Dongming
    2009, 20(14):  0-16391642. 
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    Experiments of borosilicate glass sheet reverse bending by
    CO2 CW-laser were successfully presented, and suitable processing parameters of
    reverse bending were given for specimen with thickness of 150μm. The influences of scanning number and specimen width on bending results were investigated,and then experimental phenomenon was analyzed by comparing with the forward bending.In view of the suitable processing parameters and experimental results,the buckling mechanism can be sited as the laser forming mechanism responsible for reverse bending of glass sheet.The reverse bending progress increases the flexibility of laser forming and provides a new
    way in machining for intricate parts.

    Research on Contour Control Method of CNC Mechanical 
    Polishing Machine for Aluminum Alloy Wheel Hub Surface
    Wu Changlin;Ding Heyan;Chen Yi
    2009, 20(14):  0-1699. 
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    An advanced and novel computer numerical control mechanical polishing machine was developed.The machine is of double-layer and vertical struction,
    and the five-axis CNC system is based on cylindrical coordinate. The machine was
    suitable for mechanical polishing aluminum-alloy wheel hubs and can even polish one wheel hub with three polishing tools at the same time.How the machine worked was introduced, and especially how the polishing tools followed the surface was discussed,which
    was based on the hybrid control of position, orientation and polishing force.The CL data
    was from the wheel hub’s CAD/CAM model.Many polishing experiments have showed that the special purpose CNC polishing machine with surface following control system has the same effect on surface roughness as with skilled workers,while the special
    purpose CNC polishing machine is more efficient and can replace many migrant workers in wheel hub machining.

    Research on Influence of Friction Surface Temperature on the 
    Friction Coefficient of Micro-car Clutch Friction Material
    Lü Juncheng;Mo Yimin;Tang Chunqiu
    2009, 20(14):  0-16391642. 
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    According to GB5763-98 national test standards of the fixed-speed friction tester,friction performance test was designed for micro-vehicle.Based on the stable load the frictional tests were carried out under the variable speed and the different ambient temperature,and the mechanism of friction coefficient change was analyzed.The micro-car clutch main fault of the started shaking and clutch ablation were explained from the view point of friction coefficient of friction materials.

    Research on Hydraulic Successive Lifting and Lowering System 
    Pan Liuping;Xiao Ziyuan;Mi Zhinan
    2009, 20(14):  0-1699. 
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    In order to satisfy the requirements of oversize structure lifting and lowering successively and eliminate accessional inertia loads along with impacts because of frequent startup and stop,the movement mechanism of successive lifting and lowering was thoroughly studied in a continuous hydraulic lifting device in view of kinematics.Two parameters——load transferred displacement and speed difference which had great influence on lifting efficiency were computed with optimization.Mathematical model of successive lifting and lowering control system was set up.Through MATLAB simulation and successive lifting and lowering device test,it can be concluded that continuous hydraulic lifting device can fulfill lifting and lowering continuously and synchronously.

    Stability Analysis of Longitudinal Gradient Climbing for Walking Mobile
    Excavator
    Han Jun;Chen Gaojie;Tao Li;Wu Jibing;Wang Hongjian 
    2009, 20(14):  0-16391642. 
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    For purpose of analyzing the stability of longitudinal gradient climbing for walking mobile excavator,a static model including multi-degree system for working device and chassis mechanism was described,and the additional inertia moment of working device during climbing was considered.A mathematical model of multi-objective optimization for walking mobile excavator was constructed,and the utility function method was employed to solve the optimal model.The maximum climbing slope and state parameters of working device and the chassis were optimized.The results show that the proposed method has its merits, such as simple and reliable.As the additional inertia of working device in maximum extended state was taken into account,the application of multi-objective optimization can make result more reasonable and applicable.The results can provide theoretical basis for confirming the climbing parameters of the walking mobile excavators and safety control.

    Research on a Novel Piezoelectric Type Electro-pneumatic PWM Proportional Valve
    Xu Youxiong;Li Xiaoning
    2009, 20(14):  0-1703. 
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    The traditional electro-pneumatic PWM(pulse width
    modulation) proportional valve driven by electro-mechanical converter of electromagnet has the disadvantages of slow response and poor control precision etc.To solve this
    problem,a novel piezoelectric electro-pneumatic PWM proportional valve driven by the electro-mechanical converter of piezoelectric stack was presented,where its displacement
    was amplified by the amplification mechanism based on flexure hinges.Then the
    mathematical model of PWM proportional valve was set up.On this basis,a prototype was fabricated and its related test was researched.The effect of PWM carrier frequency,proportional control coefficient and flow load on the valve performance was analyzed. And the compound control method combined with pressure feedback,P control and PWM was applied to enhance the steady precision of valve.The experiments indicate that the valve has fast response and high steady precision,with good industrial application prospect.

    Research on NURBS Curve Interpolation Algorithm Based on Filtering
    Zhang Xiaohui,;Yu Dong;Hu Yi,;Sun Weitang
    2009, 20(14):  0-16391642. 
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    An interpolation algorithm was developed for non-uniform rational B-spline curves (NURBS) interpolation while considering machining accuracy,the
    acceleration/deceleration capability of machine tool and the acceleration varying continuity.This algorithm can adaptively adjust the machining velocity according to change of curvature,while filtering technology were applied to keep acceleration continuity during the whole interpolation process,so it reduces mechanical shock and improves machining precision and machining efficiency.Finally the designed experiments show that the proposed
    interpolation algorithm can achieve high-speed,high-precision and efficient machining of NURBS curve.

    A FSMC(fuzzy sliding mode control)-type Iterative Learning Control 
    Approach for Machine Tool Linear Feeding Servo System
    Cao Yong,;Li Huade 
    2009, 20(14):  0-1703. 
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    An iterative learning servo controller based on fuzzy sliding
    mode was proposed to control the mover position of NC machine tool linear feeding servo system to track reference position. On the basis of linear feeding servo structure and motor mathematical model with disturbance, the structure of iterative learning servo controller and its learning law were analyzed in detail. The span of equivalent control gain, switch control gain and fuzzy control gain was determined by sliding mode arrival condition. The experimental results demonstrate that this method has a merit of iterative learning and sliding mode control together, and the system has a good position tracking ability and robust performance.

    Design of a New Type of Piezoelectric Linear Motor Based on Non-resonant Vibration
    Huang Weiqing;Meng Yimin
    2009, 20(14):  0-16391642. 
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    A new type of piezoelectric linear motor using piezoelectric
    stack was proposed herein.It operated on non-resonant vibration and used double driving feet.Driven by four sine wave signals with the same frequency and phase difference of
    90°,the two driving feet moved along the elliptical trajectory alternately and pushed the slider running linearly.Compared with piezoelectric motors which were based on resonant
    vibration,it possessed following advantages: its working state is stable under the interference of external factors and the operating frequency is adjustable.The experimental
    results show that within a certain range of frequency the speed of the motor is proportional to
    the operating frequency.The maximum thrust force of the motor is 4.1N and the maximum velocity is 3.7mm/s.

    Application of Genetic Algorithm and Penalty Function Method 
    in Roll-Forming Process Parameters Optimization
    Luo Zhigao;Wang Xiang;Li Ju;Chen Kun
    2009, 20(14):  0-1703. 
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    According to the difficulties of adjusting the process parameters of conical rollers roll-forming, a mathematical model was established to optimize the rolling process parameters, and the multi-constrained objective function was transformed into unconstrained objective one using penalty function method, then fitness function was established which was suitable for genetic algorithm to optimize the rolling process parameters. At last, the graph about the objective function was given, which was solved by GA method and the inside point penalty function. Through the graph, the best technology parameters were obtained. Through the experiments, we compared the standard flight with rolling flight. Experimental results show that the method of using GA to optimize rolling parameters is feasible, and it also plays a great guide role in actual manufacturing in factory.

    A Fault Diagnosis Approach for Rolling Bearings 
    Based on Time Series Decomposition and Blind-Equalization
    Zhang Jinyu;Huang Xianxiang 
    2009, 20(14):  0-16391642. 
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    After analyzing the shortcomings of current bearing fault diagnosis technologies,a novel enhanced blind equalization(BE) technology based on time-series decomposition(TD) analysis was proposed to extract directly impacting features and diagnose bearings’ faults herein.First,the blind equalization model and algorithm of impacting signal processing of rolling bearings were established based on the BE theory and
    eigenvector algorithm(EVA) algorithm.Then,the TD theory and method were applied to the model and algorithm. After these, the enhanced signal processing and fault diagnosis algorithm based on TD and BE was proposed,and the improving method of the inherent shortcomings of the algorithm was presented.Finally, the built model and algorithm were applied to two impact experiments and two real engineering data for verification.The results show that the method is very effective in extracting the impacting features and fault diagnosis for rolling bearings. 

    Study on Mechanical Properties of Biomimetic Interventional Micro Robot Operating in Artificial Artery
    Chen Bai;Yang Pengfei;Chen Sun;Wu Hongtao
    2009, 20(14):  0-1703. 
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    Based on the locomotion principles of gastropoda, a novel interventional micro robot was presented,which has the ability to resist the attack of flowing
    blood.Based on the experimental data of healthy adults’artery near the heart,the simplified numerical models of the robot’s operation environment were built.The main factors which affected the blood flow rate were analyzed.Also the ranges of the impulsive
    force produced by the blood stream when the robot operated in the arterial environment
    were calculated. According to the theoretical results,the needed friction forces applied
    to the robot’s stationary unit were analyzed.All the researches will give the basis for the control of the micro robot.

    Sparse Signal Decomposition Method Based on Multi-scale
    Chirplet and Its Application to Gear Fault Diagnosis
    Peng Fuqiang;Yu Dejie;Luo Jiesi;Yan Ruolei
    2009, 20(14):  0-16391642. 
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    Based on the chirplet path pursuit and sparse signal decomposition,a method of sparse signal decomposition based on multi-scale chirplet was proposed,and applied to the decomposition of gear failure vibration signals.The method projected
    the signals onto the multi-scale chirplet base functions.Because of the multi-scale features of the base functions,this method is more applicable to the decomposition of
    non-stationary signals whose frequency is time-varying.If the gears fail,the vibration signals are multi-component AM-FM signals which fluctuate with the rotating speed,the proposed method is very suitable to obtain the meshing frequency and modulate frequency which fluctuates with the time,so it can be used to identify the state of gearbox.A simulation example and an example of its application have proved the effectiveness of the method.

    Modeling and Effects on Open-loop Frequency for Servo System with Backlash
    Zhou Jinzhu;Duan Baoyan;Huang Jin
    2009, 20(14):  0-1703. 
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    A model of servo system considering backlash and
    flexibility of shaft was established,and two formulas which can calculate the resonance frequency and anti-resonance frequency of servo system were obtained.Moreover,a servo system with a two-stage reducer was used to investigate the effects of backlash and gear ratio distribution on open-loop performance,and some conclusions are acquired,which will be helpful for designing a controller of servo system in engineering.

    Prediction and Measurement of Subsurface Damage Thickness of Silicon Wafer in Wire Saw Slicing
    Gao Yufei;Ge Peiqi;Li Shaojie;Hou Zhijian
    2009, 20(14):  0-16391642. 
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    An abrasive machining in wire sawing process
    was considered as moving indention subjected to normal force and tangential force.Based on indentation fracture mechanics theory,the calculation
    formula of median crack propagation length was analyzed by synthetically considering the contributions of elastic stress field and residual stress field beneath the abrasive.The depth of median crack propagation layer was postulated as equal as to the subsurface damage layer thickness (dSSD),and the lateral crack depth was equal to the surface roughness Rz,thereby a theoretical model of relationship between dSSD and Rz was founded for predicting the dSSD.Moreover,a bonded interface sectioning technique with scanning electron microscope(SEM) was employed to measure the silicon dSSD.The results indicate that the experimental measurement values coincide with the theoretical prediction ones comparatively.The theoretical model can be used for predicting dSSD rapidly,expediently and accurately.

    Reference Point Based Registration Algorithm for Binocular Stereo Vision System
    Wei Hu;Liu Shenglan;Zhang Liyan;Zhang Hui
    2009, 20(14):  0-1703. 
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    A multi-view range image registration algorithm based on reference points for binocular stereo vision system was introduced herein. The algorithm included two phases:crude registration and global registration.Firstly,an incremental crude registration method was proposed for registering each newly scanned range image into a common coordinate frame.Then an iterative algorithm using singular value decomposition for global registration was adapted to optimize the crude registration result. Two improvements for the global registration were carried out.One was to assign the weights to reference points automatically,which allowed the algorithm to decrease the global registration error effectively.Another one was to classify the types of registration network and did the iteration through a planned sequence so that the number of iterations can be decreased in some special cases. Experiments on real scanned data demonstrate the validity and efficiency of the algorithm.

    An Intelligent Sampling Based Space Mapping Metamodeling Technique and
    Application for Drawbead Design 
    Li Enying;Li Guangyao
    2009, 20(14):  0-16391642. 
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    According to the technical bottleneck of the metamodeling technique and potential drawbacks of design variable-based space mapping algorithms,the response-based space mapping metamodeling technique was suggested herein.To improve the efficiency of the suggested metamodeling technique,an intelligent sampling
    scheme was integrated in the proposed system.In order to validate the performance of the proposed method,the intelligent sampling-based space mapping metamodeling technique was applied successfully for drawbead design in sheet forming optimization.

    材料工程
    Prediction Model of Coating Thickness in Hot-Dip Galvanizing
    Zhang Qingdong;Huang He;Chang Tiezhu
    2009, 20(14):  0-1703. 
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    A zinc coating weight model was developed to predict the coating weight in 1550CGL.The model developed as functions of jet pressure(P0),impingement distance(Z),slot gap(D) and strip velocity(Us).The mean pressure and shear stress distribution was calculated through numerical simulation.The calculated results show good agreement with measured data,which can be used as a pre-setting model.The semi-analytic and semi-numerical method can used for other air knife flexibly. 
    Variable Structure Low Cost Control for Wheel Hub Motor on Electric Vehicles
    Wei Haifeng;Li Pingping;Liu Guohai;Jia Hongping
    2009, 20(14):  0-16391642. 
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    A system solution of detection and control based on sliding mode variable structure was proposed, according to the actual driving of electric vehicles. The torque current sampling method was modified by using low cost hardware to improve the accuracy of detection.Torque ripple suppression analysis and the proof on robustness of variable structure controller were conducted. Simulation and experimental research verified the proposed control scheme in self-built prototype. Experimental results show that the designed scheme is feasible and effective for the wheel hub motor driving of electric vehicles.

    A Simulation Study of Transient Thermal Load of a Friction Pair in DCT
    Liu Zhenjun;Wang Yingying;Qin Datong 
    2009, 20(14):  0-1703. 
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    Characteristics of both the dry and wet clutch in the dual clutch automatic transmission(DCT) were analysed.The influencing factors of the the daul dry clutch performance and lifetime were especially researched, and the temperature rise caused by the clutch sliding was proved to be as the key factor.The powertrain dynamic model was established for the DCT vehicle launching process,and the friction work of the pressure plate friction pair was also simulated based on the DCT launching control rule.The transient temperature field distribution of the friction disk and the temperature changes in the pressure plate under the repeating heavy duty hill start process were analysed in ANSYS.The effect of the pressure plate thermal capacity on the temperature rise was also analysed herein.

    Study on EPS Using Sugeno-Fuzzy and PID Filter Control 
    Liu Jun;Chen Wuwei
    2009, 20(14):  0-16391642. 
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    Based on introducing the structure and work principle of vehicle EPS,a dynamic mathematical model was established.According to the characteristics of output control of assist power motor objective current,Sugeno-fuzzy controller was designed,at the same time,PID closed-loop feedback controller was applied to control the actual motor current.To make the control effect better,the control signals were filtered with scope and frequency filter.The result of analog simulation,hardware-in-loop simulation test shows that
    the performance of control becomes better by using this design.