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Table of Content

    10 March 2008, Volume 19 Issue 7
    Cause and Identification of Inactive Joints
    Yang Dongchao;Bin Yang;Jia Zhenzhong;Zhao Danpu
    2008, 19(7):  0-761. 
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    The prime reason of inactive joint’s existance is its speed which is linear independent of other joints.This reason was analyzed through several examples. An identification method of inactive joints based on screw theory was given. It is unnecessary to calculate Jacobian matrixes in this method.

    Dynamics Response Analysis of Precision Double Linear Motor with Air-bearing 
    Yu Xianzhong;Chen Xuedong;Ye Yixi;Jia Wenchuan
    2008, 19(7):  0-881. 
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    The precision double linear motor in high resolution step & scan projection-lithography machine utilized the air-bearings to achieve high-speed and high-precision motion with submicron positioning accuracy. With respect to the effect of the characteristics of gas-solid coupling on motion accuracy of the linear motor,a model of the precision linear motor was established by finite element method.Based on the model,the dynamic response was analyzed by the modal method under different conditions, which the acceleration response curves were obtained in X, Y, Z direction respectively.And the dynamic response was proved with experimental modal, which the natural frequency was obtained.The results of simulation are in agreement with those of the experiment and the deviation is 10% below,thus the model is reasonable and feasible. It is helpful to dynamic optimization design and control design of the precision double linear motor with air-bearing in the future work.

    Study on Piezoelectric Micro-gripper’s Control Based on Dahl Model
    Zeng Xiangjin;Huang Xinhan;Wang Min
    2008, 19(7):  0-761. 
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    micro-gripper that actuated by piezoelectric cantilever was developed for the need of micro parts assembly. The displacement-voltage relationship model was given herein. For hysteresis of piezoelectric ceramic, a mix control algorithm was presented, which employed the hysteresis offset control model based on Dahl and PID control model. The results of micro-assembly prove that the model is efficiency and feasibility.

     

    Research on Backlash and Friction Compensation for Precision Machine Tools during Reversal
    Zhang Daxing;Jia Jianyuan;Guo Yongxian
    2008, 19(7):  0-881. 
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    Backlash and friction have profoundly influence on the performance of speed and position control system. The disengaged process of driving axle and bearing axle was investigated, and the demands without overshoot during reversal of high precision machine tool were considered. The dynamics model was established based on the technique of adaptive variable structure control. The parameters of sliding mode can be variable due to the running state, which can compensate the influence of backlash and friction, and satisfy the demand of high precision, rapidity and non overshoot. The feasibility of this method was validated by simulation results.

    Design and Characteristic Test for Throttle Aperture of Hydro-pneumatic Spring with Superposition Slices
    Zhou Changcheng,;Yuan Guangming
    2008, 19(7):  0-761. 
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    The sketch of hydro-pneumatic spring was shown, the superposition throttle slices and the adjustment gasket were studied, the stress computation formula of superposition throttle slices and the thickness design formula of adjustment gasket were established. With the velocity and the pressure of opening valve of hydro-pneumatic spring, throttle aperture design formula of hydro-pneumatic was built, the affection of superposition throttle slices and adjustment gasket thickness on the throttle aperture was analyzed. With the practical example of hydro-pneumatic spring, the superposition throttle slices, the adjustment gasket and the throttle aperture were designed, the equivalent thickness, opening valve characteristic and stress intensity were validated, and the performance test was conducted for the designed hydro-pneumatic spring. The experimental and analytic results show that the methods of throttle aperture design for hydro-pneumatic spring is reliable, which has important reference value for hydro-pneumatic spring design. 

    Tool Path Planning of Spray Painting Robot Based on Genetic Algorithms
    Zhao Dean;Chen Wei;Tang Yang
    2008, 19(7):  0-881. 
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    A complex curved surface has to be divided into several patches and the path planning for each patch was performed. The path integration problem can be modeled as an open rural postman problem (ORPP), and a graph transformation method by using a Hamiltonian graph represented all the required edges in the ORPP. A genetic algorithm was advanced to solve the ORPP. The chromosome of GA made use of both numbers of the vertexes in the Hamiltonian graph and numbers of the edges in the original graph, which was a new encoding method and was able to search optimal solutions within the entire fields. Simulations were carried out on automotive body parts and the results validate the proposed algorithm.

    Analysis of Factors Influencing Cutting Quality and Strength Parameters of Rolling Cut Shears
    Zhang Xiaoping,;Yang Gangjun;Wang Junfang;Zhang Delin
    2008, 19(7):  0-761. 
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    For the optimization of mechanism design of rolling cut shears, a CAD software of rolling cut shears was developed and was used for the analysis of the factors such as crank radius, link rod length, phase difference, center distance of cranks and the offset position of upper blade carriage, which influenced the cutting quality, strength parameters and the load of main parts. The study results provide the designers of rolling cut shears with important design references. The developed CAD software can be used as a convenient manner of rolling cut shears optimum design.

    Simulation and Test of V-shaped Metal Bellow Properties
    Ma Wei;Li Jishun;Zhong Yuping;Duan Mei;Zong Yingchao
    2008, 19(7):  0-881. 
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    This paper carried out the calculation of the stiffness and stability of V-shaped metal bellow through finite element method and testified with experiments. Results show that the stiffness and stability of V-shaped metal bellow are of very strong nonlinearity. The calculation through non-linear finite element method consists with experimental results. Non-linear finite element model is suitable to simulate the critical pressure and buckling modal of V-shaped metal bellow.

    Study on Parameter Optimization of Profile Curve Design on a Novel Differential Twin Screw Kneader 
    Wei Jing;Zhang Guanghui;Li Fengji;Jiang Chunlai
    2008, 19(7):  0-761. 
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    A novel extruder and mixing roll used for high viscosity material mixing and malaxating,differential twin screw extruder was presented.The working principles of the differential extruder were analyzed.The theory of profile curve design and mathematical model of the extruder were established by using gear meshing theory as well as design method of twin screw pump.The design parameters of the differential extruder were analyzed and the variable proportions of volumetric efficiency were studied when distance a and tooth number ratio Imf were selected. It can be concluded that: when the profile curves of female and male rotors are made up of cycloids, the best transportation and self-clearance result can be obtained. The equation of optimal distance a is deduced when the shivering and crumbing performance are considered.The equations of the profile curves of differential twin screw rotors as well as practical examples are put forward.

    Information Management Technology of Cable Harness Virtual 
    Assembly Planning for Cross Assembly
    Wan Bile;Ning Ruxin;Liu Jianhua;Cheng Yue;Liu Zishuang
    2008, 19(7):  0-881. 
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    Firstly, based on the analysis of the information that needed to be managed in cable harness virtual assembly planning process, the storage structure based on assembly task and cable harness routing task was put forward, which can record the cable harness virtual assembly planning history. Secondly, post-processing of outcome information was described in three aspects: generation of BOM, producing initialization assembly planning documentation, recording assembly animation. Finally, the above techniques and methods were validated in self-developed virtual assembly prototype software system named VAPP through instances.

    Robust Adaptive Compensated Control for Biped Robot
    Huai Chuangfeng;Fang Yuefa;Guo Sheng
    2008, 19(7):  0-761. 
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    A globally stable robust adaptive compensated controller for complicated biped robot system was designed, the uncertain conservative bound was known. The parameter drift, conservative robust gain and control system chatter of designed controller were avoided or decreased. The work presented is significant for improving controller robusticity and practicability. Eventually, simulation results were used to confirm the validity of proposed method. Else, a biped walking robot is able to keep balance even in the presence of disturbing forces.

    Study on Task Scheduling in Collaborative Product Development
    Song Lijun;Yang Yu;Yang Jie,;Wang Weili
    2008, 19(7):  0-881. 
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    Aiming at the complexity and dynamic for task scheduling in collaborative product design, an online scheduling method based on the minimum finish time was proposed. The rest disposing time and weight of task were determined through the designer’s behavior state in collaborative design. Furthermore, the optimized scheduling on three kinds of decision spot during the online scheduling and the task scheduling with the restrictions were studied, which lead to the task scheduling rules of collaborative design. Finally, a case study verified the availability of sequencing method.

    Analysis of Stress and Strain Field in Twice Cross Wedge 
    Rolling the Axial Part with Large Area Reduction
    Lou Yizhi;Zhang Kangsheng;Hu Zhenghuan
    2008, 19(7):  0-761. 
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    The axial part with large area reduction was numerically simulated by three-dimensional software named DEFORM-3, which was based on three-dimensional rigid plastic theory. The important information of stress and strain field was obtained and the shape of the rolling part by FEM was basically the same as the actual part. The results of simulation show that the center of workpiece with large area reduction by twice cross rolling has greatly deformed; the center will more produce internal defect such as center porosity as it bears longer and larger tensile stress on the cross-section. The experiments prove that the rolling part has a large cavity on symmetric plane by the process parameters.

    Research on Accelerartion and Deleration for CNC Machine Tools Based on Filtering
    Yu Dong;Hu Shaohua;Gai Rongli;Bai Zhanwei
    2008, 19(7):  0-881. 
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    For the CNC machine tool vibration induced by unsmoothed velocity and jerk during beginning /ending stage, an algorithm was proposed combining the linear acceleration/deceleration algorithm with the moving average filtering. The functions of velocity, acceleration, and jerk with respect to discrete time were studied, and the algorithm equivalence to the S-shape acceleration and deceleration was proved. The implementation and experimental results were given in detail. The experimental results show the effectiveness.

    Transient Thermo-structural FEM Analysis of Ultrasonic Wire Bonding in Electronic Package
    Ding Yong;Zheng Yongyue,;Wang Xintang
    2008, 19(7):  0-761. 
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    Thermal-structural analysis was performed for ultrasonic wire bonding (UWB) by three dimensional finite element method (FEM). To simulate the long gold wire and large bond pad, an equivalent method was presented in thermal analysis. The FEM analyses show that the bulk temperature rise in UWB is far lower than the melting temperature of the wire and bond pad, and that indicates the bulk temperature is not the direct mechanism of UWB. Smaller bond pad leads higher bulk temperature, so that the wire bondability can be improved by reducing the pad size. Higher bond force means higher bulk temperature, but too high bond force will impair the gold wire. 

    Sub-functional Models of VR-based Virtual Test Technology
    Guo Tiantai;Wang Xiaona;Xu Zhiling;Yu Guiying
    2008, 19(7):  0-881. 
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    This paper studied the sub-functional models of VR-based virtual test technology by setting up its interaction model, simulation model and test model, and finally gave an example of the approach discussed. Thus the multiple discipline nature of VR-based virtual test technology is revealed, paving the way for further research, and a foundation for practical implementation of VR-based virtual test technology is laid.

    Adaptive TVAR Time-frequency Analysis Based on Wavelet and Its Application in Fault Diagnosis
    Wang Shengchun;Han Jie;Li Jianfeng;Li Zhinong
    2008, 19(7):  0-761. 
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    Time-varying autoregressive (TVAR) modeling method of non-stationary signal was studied. In the proposed method, time-varying parametric identification of non-stationary signal can be translated into a linear time-invariant problem by introducing a set of wavelet basis functions. Then, the parameters were estimated using recursive least square algorithm with a forgetting factor and the adaptive time-frequency analysis was achieved. The simulation results show that the proposed approach is superior to the short time Fourier transform and Wigner distribution. At last, the proposed method is applied to the fault diagnosis of bearing,and experimental result shows the proposed method is effective in feature extraction.

    Measurement of 3D Curve Structures by Using One Hand-held Digital Camera
    Ding Zhi’an;Zhang Liyan;Zheng Jiandong;Zhang Weizhong
    2008, 19(7):  0-881. 
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    A new method for 3D measurement and model reconstruction was introduced. First, we marked the interested curve structures on the object to make them visually outstand from the background. Then multi-images of the object were taken by using a digital camera. The images partially overlaped each other. A semi-automatic method was put forward to extract the marked curves on the images. After automatically recover the camera poses, the curve correspondences on stereo image pairs were optimally established. Finally, the 3D curves structures were recovered by using the stereo triangulation method. The proposed method has the following advantages: (1) the hardware used for the measurement is quite simple; (2) the measuring process is very convenient and flexible; (3) no registration is needed for the digitized data obtained from different views; and (4) there is no redundancy in the digitized data for model reconstruction. The method can be widely used in reverse engineering and quality inspection. 

    Neural Network-based Robust Tracking Control for Nonholonomic Mobile Robot
    Peng Jinzhu;Wang Yaonan;Yu Hongshan
    2008, 19(7):  0-761. 
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    To deal with the unknown factors of nonholonomic mobile robot, such as model uncertainties and external disturbances, a robust controller with bounded estimation based on neural network was proposed. The knowledge of dynamics parameters and external disturbances of the mobile robot were assumed to be unknown. The proposed controller can overcome the uncertainties and the disturbances. And the stability of the proposed controller was proven by using Lyapunov function. The simulation results demonstrate that the proposed method has good robustness and adaptation.

    A Multi-Objectives Method of Facility Location Based on Genetic Algorithm
    Li Bo;Ma Dakui;Cui Xin
    2008, 19(7):  0-881. 
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    This paper proposed a multi-objective model of facility location.Based on genetic algorithm(GA),a new hybrid coding method using the integer and floating number was presented. The enumerable method guarantees each individual in the population to satisfy the constrains, thus the punishment function was avoided. The two adjustable parameters made the evolution process jump out of the local best solution perfectly.The application of the fitness assignment based on Pareto ranking attained inferior solution set of the multi-objective and multiple options were provided to the decision-maker.Finally,the simulation result shows that the algorithm is effective.

    Auto-Body RSW Monitoring System Based on Thermal Expansion Displacement
    Zheng Haining;Zhang Yansong;Xu Jun;Chen Guanlong
    2008, 19(7):  0-761. 
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    A real time auto-body resistance spot welding quality monitoring system based on thermal expansion displacement was designed. Displacement
    sensor,MCU and PC were integrated in the system while a HMI(human-machine interface) was programmed. The thermal expansion displacement data during spot welding
    were acquired and compared with the theoretical thermal displacement curve to achieve the functions of monitoring, alarm and faults diagnosis of the welds quality.The stability and reliability of the monitoring system was confirmed by practical applications in the workshop and the system can be widely used.

    Research on Technology of Waste Printed Circuit Board Recycling 
    Based on Supercritical Fluid CO2
    Liu Zhifeng;Zhang Baozhen;Zhang Hongchao,
    2008, 19(7):  0-881. 
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    The PCB scraps were treated by a device with high temperature and pressure, and the principle of PCB scraps recycling with supercritical fluid CO2 was analyzed. Four factors affecting PCB delaminating in processing were studied by means of orthogonal experiment, using response surface methodology, three primary factors: temperature, time and the volume of the co-solvent (water) were researched, a quadratic polynomial equation model of the delaminating result of PCB was constructed and the optimum recycling condition was analyzed. The results show that the optimum temperature, time, the volume of water and pressure for PCB recycling are 288℃, 222min, 148ml, 20MPa respectively when the temperature changed from 250℃ to 290℃.

    Experimental Research on Application of Digital Piercing and Withdrawing Micropipette Device in Microinjection
    Tian Guizhong;Hou Liya;Zhang Weiyi;Wang Gongjin,;Tan Xiaodong
    2008, 19(7):  0-761. 
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    In order to resolve the prolems of low penetrating speed and positioning precision of micropipettes in microinjection, a novel digital piercing and withdrawing micro-pipette device(DPWMD) was presented for cell engineering. The DPWMD was alternately actuated by inertial force and friction force. Using DPWMD, an experimental system for digital microinjection was developed primarily. With experimental animal of Kunming mouse, the digital microinjection experiments were executed for mouse oocytes. With estimating criterions of cell distortion ratio and piercing efficiency, the influences on experimental efficiency were respectively analyzed with change of DPWMD’s drive voltage and frequency. The control parameters of DPWMD were optimized by experiments. With analysis of the result data, the successful rate is improved remarkably in the digital microinjection experiments of mouse oocyte. Microinjection experimental efficiency comes to 149 oocytes per hour. The digital piercing and withdrawing micropipette device can fully meet the needs of microinjection.

    Research on the Impact between Balls and Re-circulating Mechanism in Ball Screw
    Zhang Zuoying,;Song Xianchun;Jiang Hongkui;Li Chao
    2008, 19(7):  0-881. 
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    A Mechanical model of impact and contact between the ball and
    re-circulating mechanism in ball screw was brought forward according to the Hertz
    contact model and classical impact theory,along with the joint relationship of re-circulating mechanism and nut taken into account.Then the formula of the impact force and contact time was induced,which the elastic coefficient of restitution was considered in contact time calculation.Moreover,a special test unit was designed for contact time measurement and the contact time was measured. The result indicates that the new model proposed herein is closer to the practical situation than the old model proposed in literature.Based on the work mentioned above, the influence of impact angle, parameters of structure and material on impact force was analyzed by numerical simulation.

    Influence of Strain on the Hot Deformation Behavior of Al-1Mn-1Mg Alloy
    Chen Yonglu;Chen Wenzhe;Chen Dinggui;Hong Lihua;Fu Gaosheng
    2008, 19(7):  0-761. 
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    Compression test at elevated-temperature of Al-1Mn-1Mg alloy prepared by different treatments (melt-treatment and homogenization) was carried out with the aid of Gleeble 1500 thermal simulation machine. The effects of strain on material constants of hot deformation were discussed emphatically by analyzing the feature of flow stress curves, and the hot deformation microstructure of aluminum alloy was studied by OM and TEM. The results show that dynamic softening is easy to occur in these ingots and flow stress becomes steady finally; the material constants of hot deformation are procedural parameters that stress-level coefficient α, strain rate sensibility exponent m and deformation activation energy Q are all increased with strain increasing, while stress exponent n is decreased gradually; the values α and m of the alloy homogenized are the biggest and the value n is the smallest, dynamic softening effect of the alloy is the most obvious, which can deform evenly; influence of strain on the value Q of the alloy homogenized is a little and the average value of Q is only 176.5kJ/mol, so the alloy is easy to deform; the alloy matrix shows the regular recrystallization grains when the strain is 50%; dislocation cell structure re-formed in the grains with increase of strain.

    Application of LVC Work Roll in Ultra-wide Hot Strip Mills
    He Anrui;Yang Quan;Chen Xianlin;Shi Naian
    2008, 19(7):  0-881. 
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    Shape control characteristics of ultra-wide strip mill were analyzed and the result is that it has deficiencies in the aspect of shape control. In order to increase the shape control ability of ultra-wide hot strip mills, linearly variable crown (LVC) work roll was developed. The shape adjustment ability of LVC varies linearly with strip width and its shape control performances are better than that of CVC. Relevant shape control tactics models of LVC work roll were developed and applied stably in industrial ultra-wide hot strip mills. The production data show that LVC work roll can improve the strip crown control precision evidently. When the crown is within 50±18mm, for incoming strip of cold rolling and high strength pipeline steel,the percent is more than 96%.

    Pretension Analysis for Sequence Loaded Tension-bolts of Twin Columns Drive-up Assembled Frame Hydraulic Forging Press
    Huang Kui;Mo Jianhua;Chen Baijin;Huang Shuhuai
    2008, 19(7):  0-761. 
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    The classical preloading design method of assembled framework hydraulic press was determined by the assumption that transverses were rigid and tension-bolts along with braces had only deformation along axial direction. It was not agree with reality. ANSYS Corp. Ltd lately has produced cooperated simulating environment-ANSYS Workbench software, which was utilized herein to gain the forced status of tension-bolts under various preloading coefficients and discover the descending principle in order to instruct actual installing equipment.

    Research on Active Roll Control Algorithm of Heavy Tractor Semi-trailer Based on LQG/LTR
    Zong Changfu;Zhu Tianjun,;Zheng Hongyu;Tian Chengwei
    2008, 19(7):  0-881. 
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    The research set up 8 DOF dynamic model of tractor semi-trailer and put forward an active roll control algorithm based on LQG(linear quadratic regulator)/LTR(loop transfer recovery) for the vehicle roll stability.Partial-state feedback controller was established to fulfill the active roll control at 60km/h. The algorithm was proved by the vehicle simulation with steering step input. The results show that LQG/LTR controller has ability of restricting the noise and robustness.The controller can enhance the roll stability of tractor semi-trailers.

    Application Research on Multidisciplinary Design Optimization of the Full Vehicle Lightweight
    Zhang Yong;Li Guangyao;Sun Guangyong;Han Xu
    2008, 19(7):  0-881. 
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    Sampling points were obtained by using optimal Latin hypercube design of experimental method, meantime, in order to improve computing efficiency ,application of stepwise regression response surface approximate method in the MDO system of the vehicle crashworthiness and free mode of Body-In-White(BIW), the approximate model was optimized by using sequential quadratic programming method. It avoids to consume much of computing time in the traditional method and slow convergence or no convergence in the non- linear impact system. At last, it lightens the weight of the full vehicle in meeting the requirements of regulation CMVDR294 and improves first torsion mode frequency the BIW vehicle.