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Table of Content

    10 January 2014, Volume 25 Issue 1
    Theoretical Analysis and Experimental Research of Grating Mechanical Depicts Process
    Zhang Baoqing, Shi Guoquan, Shi Guangfeng, Cai Hongbin
    2014, 25(1):  1-6. 
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    At present, the “test score” processing of grating process model has the characteristics of time-consuming and low efficiency, and grating trough of mechanical characterization can't be precontrolled accurately. The microstructure and mechanical properties of grating score aluminum film were characterized herein through nano-indentation experiments. Formation of trough were studied by using finite element analysis software Deform combined with orthogonal tests. Trough base angle process model was established through study of the range data analysis and the effects of single factor experimental analysis of the data. The results show that, the process can be converted into grating wedge press process, based on the finite element simulation of tank base angle process model is available simultaneously.

    Measurement Algorithm of LCD Mounting Dimension Based on Machine Vision
    Xiao Min, Zhuang Chungang, Xiong Zhenhua
    2014, 25(1):  7-11. 
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    This paper presented an algorithm to measure the distance between the displaying area and the frame of LCD. In this algorithm, a Hough transform and a least square fitting method were combined. First, the Canny operator was implemented to find the edges of the displaying area and the frame of LCD. Second, a line position with low-precision was located using the Hough transform, and the point set near the line can be detected after that. Finally, the least square fitting method was applied to obtain the precise line edges, and then the distance between the displaying area and the frame can be computed. The experiments show that the algorithm proposed herein has relatively higher precision and efficiency. The measurement algorithm has been applied to online inspection of LCD products.

    Research and Implementation of High Speed and High Precision Electronic Gearbox Technology
    Tian Xiaoqing, Han Jiang, Xia Lian
    2014, 25(1):  11-16. 
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    Division of teeth pitch and differentiation of gear cutting machine are strict with the accuracy of multi-axis speed control. The paper built a theoretical model of software EGB based on the analyses of hobbing technology. Implementation methods of software EGB in embedded NC system were researched based on the hardware of ARM+DSP+FPGA. Strategy of acceleration/deceleration was considered at the start and cancellation stages of EGB synchronization control. The data flow among the modules in NC system was analyzed in detail. Moreover the special G codes with parameters were designed, and the EGB control through NC programming was realized in a home made NC system.

    Fault Tolerance Strategy and Workspace Boundary Identification of Adjusting Mechanism for 65 Meter Radio Telescope
    Dou Yuchao, Yao Jiantao, Hou Yulei, Zhao Yongsheng,
    2014, 25(1):  17-22. 
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    In order to realize the proper function of a 65m radio telescope's Stewart adjusting mechanism with the condition of single link at failure. At first, the degree of freedom (DOF) of the mechanism under the fault condition was analyzed using the screw theory, and the fault tolerant movement principle based on redundant DOF was proposed according to the number of the mechanism's DOF greater than that of the task needed, and the workspace of the adjusting mechanism was calculated and analyzed when it broke down at L band or S band. Then a method to identify the irregular boundary of the workspace was proposed, and the restraint of the movement scope of the mechanism by the boundary was realized. The experimental results show that the fault tolerant theory proposed herein is suitable for the pointing adjustment of the subreflector with single link at failure.

    Process Planning and Control Technology on Multi-station Working Mode of Robot Drilling and Riveting System with Auxiliary Axis
    Tian Wei, Dai Jialong, Zhou Weixue, Zeng Yuanfan, Liao Wenhe
    2014, 25(1):  23-27. 
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    Robot drilling and riveting system with auxiliary axis is a typical equipment for aircraft automatic assembly. On traditional control mode the auxiliary axis must be manufactured with higher accuracy, and more cost and longer period were needed. In order to overcome these defects, a multi-station working mode was proposed. Firstly the system composition and the work flow were analyzed. Then the process planning method of the auxiliary axis was put forward, by which the manufacture accuracy of the auxiliary axis was reduced. On the basis of that, a local closed loop control method was researched. Finally, an experimental platform was built, and results show that the repetitive positioning accuracy of the auxiliary axis is improved from 0.2mm to 0.02mm.

    Study on Comprehensive Performance of Two-spindle Denture Machining System
    Zhang Lin, Liao Wenhe, Wang Jie, Liu Zi
    2014, 25(1):  28-32. 
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    The paper presented a two-spindle rapid denture machining system with applications on CAD/CAM dental restorations. The necessary functions possessed by denture machining system in medical treatment environment were defined, and the main technical parameters and general layout structure of the system were determined. The modal tests of the system structure were conducted for the key areas vibration mode. Based on the basic theory of multi-body system, the volumetric geometric error model of the system was established. The volumetric geometric errors of the system were measured with laser interferometers and the error compensation was carried on. At last, the milling experiments of human molar crown denture were carried out with the mean surface roughness Ra value 0.8μm, which is consistent with the requirements of dental restoration.

    A Method to Predict Disc Cutter Wear Extent for Hard Rock TBMs Based on CSM Model
    Li Gang, Zhu Lida, Yang Jianyu, Wang Wanshan
    2014, 25(1):  32-35. 
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    To overcome the difficulty in prediction of disc cutter wear extent in the working process of a TBM, by using fracture mechanics theory of rock, the rock fragmentation mechanism of TBM cutters was analyzed. A new method to predict disc cutter wear extent was developed herein. Based on mechanical analysis of the disc cutter as it cuts hard rock, a model was carried out by using specific energy (SE) and the influence factors of disc cutters wear were analyzed. Data from on-site Qinling tunnel boring was analyzed in detail as an example and the comparison was made with the field data. The results prove that the prediction results are similar to the actual situation.

    Kinematics and Cartesian Impedance Control for Redundant Space Robotic Arm
    Dong Xiaoxing, Li Ge, Liu Gangfeng, Zhao Jie
    2014, 25(1):  36-41. 
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    In order to travel outside the space station safely, a 7-DOF SRA needed to be able to automatically control the contact force during connection process. This paper firstly presented the kinematic solution of SRA which used two-phase calculation to deal with inverse kinematics. Then a valid Cartesian impedance control method based on end force-torque sensor was proposed, after parameter optimization by SIMULINK,the tests were implemented on SRA. Experimental results have verified the effectiveness of the proposed method.

    Research on Assessing Algorithm for Scroll-type Cylinder Surface Perpendicularity Errors
    Hu Ronghua, Wang Lun, Chen Zhongyang, Liu Guoping
    2014, 25(1):  42-45,50. 
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    In order to achieve high-precision assessment of scroll-type cylindrical surface perpendicularity in scroll compressors, a mathematical model was established based on the least square method of the optimization approximation algorithm and was used to analyse the scroll surface outline data. Comparing the results herein with results from the German ZEISS company UMC 550 type of CMM, it shows that the algorithm is accurate and targetable. The curve of the result from the algorithm has the same trend with the result curve of ZEISS and the degree of coincidence is more than 99%. It can be assessed as a high-precision algorithm of the wrap perpendicularity.

    Research on Multi-motor Synchronization of Salivation Unit Based on Neural Network
    Wang Bo, Cao Chunping, Xu Xiaoyong, Sun Yu
    2014, 25(1):  46-50. 
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    According to the salivation unit's multi-motor synchronous control system of nonlinear, time varying, load disturbance and other vulnerable features, neural network PID controllers were designed and a strategy of realtive coupling control for multi-motor synchronization based on neural network PID contorl was proposed;Simulation results show that: the control algorithm has a good stability behavior and robust performance ,a quick convergence rate and can achieve the multi-motor synchronous control of salivation unit effectively compared with the traditional control strategy.

    Research on Representation and Reasoning for Ontology-based Injection Mould Repair Knowledge
    Wang Yi, Chen Qingxin, Mao Ning
    2014, 25(1):  51-58,64. 
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    There were the description problems which were not standardized in the mould-repair knowledge. Knowledge reasoning was necessary to use knowledge effectively in making injection mould repair schemes. According to the analysis of injection mould repair knowledge, a multi-layer knowledge representation and reasoning model based on ontology for mould repair knowledge was put forward herein. The features of the mould-repair knowledge were analized, and the model of the knowledge expression was established. The concepts, attributes, relations, and instants of the ontology were defined with the ontology design methodology. The reasoning rules and algorithm for single layer and multi-layer ontology-based mould repair knowledge were designed. At last the example about the defect of “flashing” was representated and reasoned by the knowledge model to demostrate the validity and the feasibility.

    Bacterial Swarm Foraging Optimization Algorithm and Its Application in Optimization of PID Parameters
    Chen Dongning, Zhang Guofeng, Yao Chengyu, Zhang Ruixing,
    2014, 25(1):  59-64. 
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    To overcome the shortages of slow convergence in bacterial foraging(BF) algorithm and premature in particle swarm optimization(PSO) algorithm, a bacterial swarm foraging optimization(BSFO) algorithm was proposed. The velocity updating formula in PSO was used to replace the direction vector of position formula in BF algorithm, therefore each bacterium had the ability of perceiving the position of the neighborhood bacteria and moving to the historical best position of the whole swarm. The optimal results of benchmark test functions show that the BSFO algorithm has better performance for most of the functions. Besides, the BSFO algorithm was applied to the simulation of optimization of the PID controller's parameters, which was used in an electro-hydraulic position servo system of material testing machine, and the PID control system has good control performance.

    Modeling and Analysis of Digital Hydraulic Cylinder Based on Transfer Function
    Chen Jia, Xing Jifeng, Peng Likun
    2014, 25(1):  65-70. 
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    Considering power match and characteristics of asymmetrical structure, setting the position with the minimum hydraulic spring stiffness as the orginal point, a transfer function of valve-controlled asymmetrical cylinder was deduced, a reasonable expression to count hydraulic natural frequency was given, and then a universal transfer function model of the digital hydraulic cylinder was established. Based on the model, meaning of parameters and system characteristics were analysed. And using real parameters, confirmatory simulation experiments were carried out. The results reveal that, load and the asymmetrical structure of digital hydraulic cylinder account for the performance differences between the two motion directions-positive and negative. System performance is decided by the structural characteristics of inner feedback loop, and the good stability is showed.

    Research on Efficient Cutting and Low Wire Wear Technology of HSWEDM
    Li Xiefeng, Liu Zhidong, Zhang Xudong, Li Lingling
    2014, 25(1):  71-76. 
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    At present, the highest cutting efficiency of HSWEDM has been over 200mm2/min. However, the traditional pulse power only improved pulse energy in this situation, which will cause the molybdenum wire severely worn and may be broken in short time. According to the discharging waveform of the pulse power, the differences between the traditional pulse power and high efficiency, low wire wear pulse power were analyzed, meanwhile the discharge mechanism of the efficiency and low wire wear of pulse power was also researched. The research shows that, controlling the discharge current of the leading and trailing edge by the ladder pulse and cutting off the abnormal pulse promptly can reduce the wear of the wire electrode. On the other hand, equal energy pulse used in the process, can effectively improve the chance of discharge and utilization rate of pulse. Finally, the new type pulse power supply apparently increases the cutting efficiency, improves the surface roughness of work-pieces and realizes to cut steadily in the condition of 190~200mm2/min cutting efficiency.

    A Novel Technology for Micro-fluid Dispensing Based on Two-phase Flow Dynamics
    Zhang Jinsong, Wang Zhiliang, Zhang Jianhua
    2014, 25(1):  76-81. 
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    According to driving principle, a micro-fluid dispensing technology can be sorted out to be the indirect driving and direct driving technologies. The common dispensing technologies used the indirect driving principle to realize the kinetic energy transferring from the movable medium to the stable liquid and spray the liquid droplets out of the nozzle to the substrate. The novel dispensing technology was presented first due to the direct driving principle, which was based on the two-phase flow dynamics. With a proper gas-liquid flow rate ratio, the gas and liquid streams entered the micro-mixing chamber simultaneously to form the stable slug flow, which contained the bubbles and droplets in a uniform interval and a consistent volume, respectively.

    Experimental Study of Nano-ceramic Bond Based on Super High-speed CBN Grinding Wheel
    Zhang Jingqiang, Wang Wanshan, Yu Tianbiao, Zhang Song,
    2014, 25(1):  82-87. 
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    In order to achieve the requirements of super-high speed vitrified bond of CBN grinding wheel with low-melting and high strength, nano-materials were added into formulations of the vitrified bond which was mainly based on a glass with properties of R2O+RO-B2O3-Al2O3-SiO2, a compound of pure raw chemical materials. Performances of four types bond were tested. Experimental results show that compared with traditional vitrified bond the new nano-ceramic bond has a significant advantages at its bending strength,refractoriness and infiltration. Especially, the bending strength of 4# nano-ceramic bond has reached 83.75(MPa) and its refractoriness was 795℃, and its expansion coefficient is the closet to CBN abrasive. It proves that 4# nano-ceramic bond is more suitable for super-high speed CBN grinding wheel.

    Study on Road Feel Control of Differential Steering for In-wheel Electric Vehicle
    Zhao Wanzhong, Wang Chunyan, Zhang Zongqiang, Yu Leiyan, Zhao Ting
    2014, 25(1):  87-91. 
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    In order to improve the road feel of differential steering system, the dynamics models for the vehicle including the differential steering system were built. Based on the robust control theory, guaranteeing the H∞ property, a PID controller was designed for the novel differential steering system and the simulation was conducted. The simulation results show that the novel differential steering system with the H∞-PID controller can meet robust performance of H∞ and decrease static errors of the system. It can improve the steering sensibility and system accuracy, then the driver can obtain more satisfied steering road feel.

    Effect of Flexible Microvalveson on Pressure Performance of Electrostatically Actuated Micropumps
    Zhang Yu, Wang Wen, Zhao Xiaolin, Ding Guifu
    2014, 25(1):  92-96,102. 
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    The effect of electrostatically actuated flexible microvalves on the pressure performance of electrostatic micropumps was analyzed by combining energy minimization and the analytical solution for membrane deformation under uniform pressure. The introduction of the valve volume yields a certain decrease in the pressure rise of the micropump, but the decreasing percentage is much lower than that generated by the valve volume on ordinary pumps with constant stroke. Moreover, as the valve plates of the microvalves were made of flexiblemembrane, the voltage for valve closing is much lower than the cavity actuation, leading to an enhancement in the reliability of the micropumps and microvalves.

    Research on Low-frequency Characteristics of One-pole Vibration Cylinder Controlled by 2D Valve
    Li Weirong, Ruan Jian, Ren Yan, Bai Jiping
    2014, 25(1):  97-102. 
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    The traditional electro-hydraulic exciters were very difficult to enhance the vibration frequency, so a new electro-hydraulic exciter based on single-rod hydraulic cylinder controlled by 2D valve was proposed. The scheme of electro-hydraulic exciter was described firstly, then the mathematical model was established and simulation analysis was executed. Finally, the electro-hydraulic exciter was designed and the experimental research was performed. The theoretical and experimental results show the output waveform of exciter is prone to saturation under 5Hz; with improvement of agitating frequency, the saturation phenomenon is uneasy to appear. The output force of exciter is proportional to the axial opening of 2D valve, the greater the axial opening of 2D valve, the bigger the output force of exciter.

    Design and Kinematics Analysis of Large Condenser Cleaning Robot
    Xia Hanming, Wang Yaonan, Yin Feng, Cao Wenming
    2014, 25(1):  103-107. 
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    A large condenser cleaning robot was designed herein,the structure of which was simple and was easy to control, and can on line clean large condenser automatically for long time. Model of kinematics of the large condenser cleaning robot was founded, and the forward and inverse kinematics of which was analyzed. The catastrophe problem of the robot joint value was solved. The workspace of the robot was verified that covered distribution space of bunches of copper pipes of the condenser and the robot was high flexible. The kinematics of the large condenser cleaning robot was simulated and analyzed, and results indicate the designed end-effector is rational, and can meet the working requirements, which provides theory foundation for further researches.

    Product Design Process Modeling and Simulation Based on DSM and Colored Petri Nets
    Li Haitao, Yang Bo, Yin Xiaoling, Wang Xingzu, Yao Kong
    2014, 25(1):  108-117. 
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    Combined the DSM(design structure matrix) and the colored Petri nets,this paper presented a research of product design process modeling and simulation. First, the product design process was modeled based on the DSM, and to support the description of the basic logic process, the basic nets model structure of the colored Petri nets was defined from the view of product design process characteristics. Through the mapping from the DSM to the colored Petri nets, a colored Petri nets model of product design process was established. On the basis of that, the dynamic distribution model of the effective design resources distribution was established. Through quantitative simulation analysis, the collision detection, reallocation and adjustment of the resource were realized in the product development process.As an example,a bridge crane car design was used to show the effectiveness of the method.

    Flexible Multi-body Dynamics Analysis on Cage of Angular Contact Ball Bearings
    Yao Tingqiang, Xie Wei, Tan Yang
    2014, 25(1):  117-122. 
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    Considering the structural deformation of inner, outer and cage and dynamic contact relationship among the ball, raceways and cage, a flexible multi-body contact dynamics model of angular contact ball bearings was established by FEM(finite element method). The dynamic contact simulation analysis was achieved by ANSYS/LS-DYNA and the calculated dynamics characteristics were discussed with different radial loads, rotating speeds, guide clearances. The calculated results of angular contact ball bearings were verified by theoretical values such as dynamic contact stress, angular speed of cage, dynamic impact stress and trace of cage's center. The dynamic impact stress and stability of cage are affected especially by the variety of angular speed.

    Two Scale Structural Analysis of Complex Steel Cord Analysis in Radial Tires
    Wei Yintao, Luo Yiwen, Miao Yiming, Chai Delong, Feng Xijin
    2014, 25(1):  123-129. 
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    The precise deformation and stress map of the steel cords within a TBR(truck bus raclial) tire were studied herein. Based on the theory of global modeling of a TBR, a method of local scale modeling of the steel cord was proposed. The studied results show that structural, elastic and elastic-plastic deformation stages can be clearly observed for the high elongation cord, whereas structural deformation stage is not clear for the high strength cord. All filaments bend independently under combined tension-bending loading. The neutral axis almost remains at the geometrical neutral axis for the outmost layer filaments, whereas the neutral axis moves forward to the compression zone for the innermost layer. The local stress of filaments increases dramatically with the increasing contact area among filaments. At last, by comparing the experimental results, the method of local scale modeling proposed was proved to be valid.

    Vehicle Closed-loop System Simulation Based on S-AKF Estimation and PID Control
    Shen Huan, Lin Fen
    2014, 25(1):  130-133,137. 
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    A yaw rate PID control strategy was designed based on Simulink and Carsim, effectiveness of the control strategy were verified. Then a two DOF vehicle dynamics model was established, the S-adapt Kalman filter (S-AKF) algorithm was proposed to estimate yaw rate and sideslip angle. Finally, the S-AKF estimator was combined with the PID controller to constitute a complete estimate-control closed-loop system. The entire system performance was validated through virtual test of Carsim. The results show that the control algorithm together with the estimation algorithm constitute a complete control system, which can acquire active intervention for car under necessary conditions, also improve the vehicle's path tracking ability and stability.

    A Study of Characteristics of Automobile Multilayer Sound Absorption Materials Based on Transfer Matrix
    Liu Gangtian, Ji Xiaomin
    2014, 25(1):  134-137. 
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    This paper analyzed the sound absorption characteristics of automobile sound absorption materials with the transfer matrix. Firstly, the multilayer uniform sound absorption materials were decorated, and the sound pressure and normal particle vibration velocity relationship between two layers of sound materials were obtained. Then the i layer and the i+1 layer of sound absorption materials in front of the experimental material steel plate were considered separately, and the acoustic impedance ratio between two layers was obtained. Thus, the sound absorption coefficient calculation formula of multilayer sound absorption materials would be given. Finally, instances calculation and experimental measurements of the sound absorption coefficient among the uniform sound absorption materials of three different thicknesses were carried out, and the correctness of the sound absorption coefficient was verified, which was studied from the transfer matrix characteristic calculation of automobile multilayer sound absorption materials. A theoretical basis for transfer matrix characteristics of the multilayer sound absorption materials will be provided.

    Investigation of Global Optimization Energy Management Strategy of HEV Based on PMP
    Xu Shijing, Wu Zhixin,
    2014, 25(1):  138-141. 
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    Dynamic programming usually is used to obtain the global optimal solution of the known driving cycle, but this method needs a large amount of calculation and a long computation time. To solve this problem, the models of the genset and the battery bank were simplified appropriately. Keeping the battery pack energy balanced, the battery state of charge (SOC) was used as the state variable, and the output power of the battery was used as the control variable, PMP was used to obtain the global optimal solution. And the detailed solution process was given. Compared with dynamic programming, the time required to solve by means of the method is very short.