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Table of Content

    10 January 2016, Volume 27 Issue 01
    Suspension Test System Based on Modified Elman Neural Network
    2016, 27(01):  1-6. 
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    An improved Elman neural network controller was established, which could meet multi network and multi order system. A programmable automation controller(PAC) controller was established based on modified Elman neural network, and was used to the 6-DOF suspension system test platform control; the effects of suspension parameters on wheel load utilization ratio and phase angle were analyzed. The results show that the matching of the suspension parameters can improve body vibration, reduce the suspension dynamic deflection and tire dynamic load.

    A Method of Automatically Extracting and Corresponding Feature Point Based on Law of Delaunay Triangulation
    Xu Kan, Li Wenlong, Wang Jianzhuang, Zhou Liping, Yin Zhouping,
    2016, 27(01):  7-13. 
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    Based on the law of Delaunay triangulation applied on 2D grid points, this paper proposed a method called ACDT(automatic correspondence based on Delaunay triangulation) to correspond the feature points for 2D circle array target in IC packaging environment. The experimental results show that the method can still work when there is an affine image distortion caused by oblique view angle, or the lost of feature points caused by offset and rotation of the target. It is not sensitive to the non-linear image distortion caused by lens distortion and most suitable for online camera calibration. 

    Study on Energy Consumption Model and Its Optimization Algorithm for Spot Welding Robot Trajectory
    Deng Qianwang, Luo Zhengping, Zhang Like, Cui Wei
    2016, 27(01):  14-20. 
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    An approach for optimal trajectory planning of spot welding robot manipulators was presented. By linking two points in joint space with quintic polynomial curves, energy consumption mathematical model of spot welding robot trajectory driven by permanent magnet synchronous motor(PMSM) was established based on industrial robots dynamics. The method for searching for the optimal spot welding robot trajectory based on BEGA was put forward by taking consideration of the constraints of robot kinematics, dynamics and the production cycle. In order to ensure the early global optimization and late stage convergence speed of the algorithm,the nonlinear algebraic fitness function was proposed. By contrast with the shortest time trajectory optimization, the results indicate that energy consumption of the energy optimal trajectory is reduced significantly and it also can obtain better solution in comparison with other methods.

    High Effective Inverse Dynamics Modelling for Multi-DOF Serial Robots
    2016, 27(01):  20-24. 
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    To deal with the problem of inverse dynamics modelling for multi-DOF serial robot, a recursive inverse dynamics modelling method was presented based on decoupled natural orthogonal complement. In this model, the concepts and methods of decoupled natural orthogonal complement(DeNOC) matrices were used to eliminate the constraint forces in the Newton-Euler kinematic equations. Finally, a 7-DOF serial robot was simulated by, and the results were compared with those of the recursive Newton-Euler kinematic equations. Simulation results show that the proposed method based on decoupled natural orthogonal complement can save 2/3 amount of CPU time that is spent in computing compared with the traditional approach, and the results is correct and reasonable, which can verify the reliability and efficiency of the method.

    Maximum Impact Force and Thermal Characteristic Analysis of Double-decker Catcher Bearing Used in High-speed and Heavy-load Conditions
    Zhu Yili, Jin Chaowu
    2016, 27(01):  25-31. 
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    The working performances of two types (A and B) of DDCB under high-speed and heavy-load conditions were studied based on the established rotor-drop test bed. The relevant dynamics models and heating network model were established according to the rotor-drop test bed. For different DDCB parameters, the dynamics responses of rotor and catcher bearings as well as the inner race temperature rise of catcher bearings were analyzed theoretically. Then the relevant rotor drop experiments were carried out. The research results show that type B DDCB is more suitable for high-speed and heavy-load conditions.

    Calculation and Analysis of Wind and Wave Loads of Offshore Floating Wind Turbines
    Liu Deshun, Liu Ziqi, Dai Juchuan, Long Xin
    2016, 27(01):  32-40,45. 
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    Three-floating-barrel support structure of large scale offshore floating wind turbines was researched herein. Considering the combined action of wind and wave, using the BEM theory and linear wave theory, the wind load model, wave load model, and wind-wave combination load model were built. In calculation process, different operating conditions of wind turbines were considered, the different wave load models,Morison formula and diffraction theory,were selected based on the ratio of floating barrel diameter to wave length. Load calculation results for different operating conditions, environment parameters and structure parameters were obtained, and the load characteristics were analyzed.

    Testing Research of Rotor Center Trajectory of Oil-film Bearing with GMA under Dynamic Control
    Wu Chao, Yin Xuemei, Wang Wen
    2016, 27(01):  41-45. 
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    The principles of the testing rig supported by controllable oil-film bearing based on GMA were introduced. Dynamic experiments on rotor center trajectory by use of the controllable bearing were completed, whose results show that, if the appropriate control current and phase difference are adopted and imposed on GMA, the controllable hydrodynamic bearing can restrain  the vibration value of rotor working frequency dynamically, and reduce obviously rotor center trajectory. Testing results also show that, for a certain control current, there is an optimal value of phase difference which can minimize the vibration amplitude of rotor working frequency; the optimal value of phase difference has a tendency to become bigger with the increase of control current. It is proved that the controllable journal hydrodynamic bearing with GMA has the strong ability to dynamically control the rotor-center locus and reduces the vibration of the rotor supported by the controllable bearing, with outstanding position and rotation precision.

    Optimization of a Certein Torsion Beam Suspension Based on Sensitivity Analysis
    Zhang Peng, Wang Hao, Chen Liqing
    2016, 27(01):  46-51. 
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    According to the principles of mechanics of materials, based on the spatial coordinate transformation matrix and analytic geometry of space,  the shear center of a certain torsion beam suspension was established and calculated. The model was aimed to get the kinematical equation and modify the structural parameters. By using partial derivative methods, the sensitivity formula of suspension structural parameters to the kinematics property were worked out. Based on the sensitivity formula, the most influences parameters on the kinematics property would easily get,by modifying these factors, the kinematics property of this suspension would become better. A finite element model was established to show the calculation way of the shear center was reliable. ADAMS model and test results show that the analysis method is right.

    Research on Telescopic Time-variation Dynamic Characteristics of Box-type Boom
    Zeng Weidong, Peng Jing, Ren Huili, Fu Ling, Liu Yanbin,
    2016, 27(01):  51-57. 
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    Based on the HHT(Hilber-Hughes-Taylor) implicit time integration method, a nonlinear dynamics analysis model of a crane with a friction effect was built, and the nonlinear time-variation dynamic characteristics of box-type boom were studied. The effects of friction between the boom and sliders, the elastic stiffness and damping characteristics of the telescopic oil cylinder, and the stiffness of the crane boom on vibration of telescopic crane boom were analyzed. In view of some problems about vibration of telescopic crane boom, the effective improvement measures were proposed.

    Fractal Tool Path Connection Technology Based on Improved Ant Colony Algorithm
    Wu Changyou, Dai Ning, Liu Hao, Chen Xiaosheng, Li Dawei, Shen Zhenhong, Sun Dengguang
    2016, 27(01):  58-65. 
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    To solve the problems of numerous empty trips and tool-retraction in fractal tool path, the fractal path segments were connected by border crop profiles. To determine the shortest overall connection path, an ant colony algorithm was applied to initially connect the scattered fractal path segments on the same layer of slice. Afterwards, according to the principles of the path planning, the validity of the connection path was judged, and the bad forming quality that was affected by the unreasonable connection path was removed. Selection strategy and pheromone evaporation coefficient were dynamically adjusted to improve the basic ant colony algorithm, which converged slowly and was easy to get stuck in a local optimal solution. The experimental results demonstrate that the method can effectively reduce empty trips and tool-retraction on the same layer of slice, and the improved ant colony algorithm shows good convergence and global search capabilities.

    Adaptive and Sparsest Time-frequency Analysis Method Based on Genetic Algorithm and Its Applications
    Li Baoqing, Cheng Junsheng, Wu Zhantao, Peng Yanfeng
    2016, 27(01):  66-72. 
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    To solve the choice of initial phase function, ASTFA method was proposed herein based on GA. The initial phase function of ASTFA was optimized by GA. The ability of avoiding mode mixing was studied. The analysis shows that the GA-ASTFA method has the ability of avoiding mode mixing and can suppress the pseudo components. And the component's accuracy decomposed via GA-ASTFA is better. Finally, the GA-ASTFA was applied to rub-impact fault diagnosis in rotor systems. Experimental analyses show that the GA-ASTFA method can extract the fault feature information effectively.

    Fault Diagnosis of Rotating Machinery Based on Laplacian Support Vector Machines
    Hao Tengfei, Chen Guo
    2016, 27(01):  73-78. 
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    In the intelligent fault diagnosis of rotating machinery, collecting a large number of data was relatively easy, but giving all collected data a label was often difficult. Aiming at this situation, an intelligent fault diagnosis approach for rotating machinery was proposed based on Laplacian support vector machines(LapSVM). The diagnosis example of rolling bearings shows that when the number of labeled data is limited, compared with the SVM that uses only labeled data for learning, the fault diagnosis approach based on LapSVM can improve the accuracy of fault diagnosis significantly by using a large amount of unlabeled data together with labeled data for learning.

    Numerical Simulation of Internal Flow of Nozzles and Near-field Sprary with OpenFOAM
    Gao Yongqiang, Wei Mingrui, Tan Baohua, Yan Fuwu, Dong Weitao
    2016, 27(01):  79-84. 
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    A revised cavitation model was established considering thermal effect with modified evaporation and condensation source terms,which was based on Schnerr-Sauer cavitation model of OpenFOAM toolbox. The computations for the fuel atomization process of the orifices and near nozzles were conducted by original Schnerr-Sauer cavitation model and revised cavitation model respectively. The nozzle of revised cavitation model is more intense than that of original Schnerr-Sauer model, and the area of cavitation is wider than that of original Schnerr-Sauer model. Simultaneously, the length of unperturbed liquid core of the near nozzle region is shorter and atomization of the fuel is smaller. It is dictated that the revised cavitation model can accelerate the fuel break-up and atomization.

    Prediction of Fretting Fatigue Life Based on Energy Density Method
    Ping Xuecheng, Zhao Liaoxiang, Wu Weixing
    2016, 27(01):  84-90. 
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    Strain energy based damage parameters were calculated from the stress and strain fields on contact interface. Material parameters in the damage parameter-life curve were obtained from fretting fatigue experiments. Finally, the fretting fatigue life prediction model of LZ50 steel was established. Compared with the surface wave transmission(SWT) model, it is found that the Chen damage parameter is selected as fatigue life predication. The influences of friction coefficient, rounded corner, pressure and cyclic tension loads on Chen damage parameters of LZ50 axle steel were studied, and the crack initiation position and fretting fatigue life of a CRH2 type hollow axle was also investigated.

    #br# Research and Design of Camshaft CNC Grinding Cloud Platform
    Xie Zhiming, Deng Zhaohui, Liu Wei, Liu Tao, Peng Keli
    2016, 27(01):  91-100. 
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    In view of integrating the grinding field resources, grinding cloud platform refered to the ideas from cloud computing and cloud manufacturing, which integrated and used two categories of resources in grinding domain. The structure of grinding cloud platform was proposed, research of its key technologies was used to design the software structure.Using artificial intelligence,the application requirement model was proposed,the work flow and key algorithm of the system were designed. Designing and developing grinding cloud platform system composed of five software subsystems, including the SaaS service system, the PaaS service system, the IaaS-to-PaaS replication system among distributed heterogeneous database, the IaaS service system, the user login and register management system, which made the enterprises more convenient optimization in resource utilization. The grinding cloud platform was applied to practical productions, which improves the production efficiency effectively and reduces the production cost.

    Reliability Assessment of Safety-instrumented Systems Operated in High-demand Mode
    Wang Yukun, Liu Zixian
    2016, 27(01):  101-104,108. 
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    Currently, the research of reliability analysis of high-demand safety instrumented systems was rare. Considering the process demands, item failure modes, proof test strategy and maintenance, a Markov model of the 1oo2 voted group was developed for the reliability analysis. After that, the effects of demand and proof test strategy on the reliability of the voted group were explored, respectively. The results show that the reliability of the voted group decreases with the demand rate and the proof test frequency. The operating state of the group is dominantly verified by demands if the demand rate is larger than the proof test frequency, and by proof tests otherwise.

    Data Mining for Orders' LT Forecasting in Wafer Fabrication
    Wang Junliang, Qin Wei, Zhang Jie
    2016, 27(01):  105-108. 
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    The accurate prediction of LT plays an important role to help semiconductor manufacturers keep the promises of an accurate and steady delivery-time. However, the large production scale, and long cycle time significantly substantiated the complexity of such a problem. Based on large amounts of manufacturing data, a regression-based model which took account of thousands of parameters was proposed to obtain the correlation among 1669 manufacturing variables and LT. To select “LT-related” variables which had high mean Z-transformed correlations, the Fisher Z-transformation was applied, and the case-based reasoning method was designed to forecast orders' LT accurately.

    Parameter Identification of Servo Control System Based on   Unbiased  Least  Square  Method
    Wu Lulu, Han Jiang, Tian Xiaoqing, Xia Lian
    2016, 27(01):  109-113. 
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    Aiming at accurate parameter identification  of  a  servo  control system and the  demands of high performance motion control algorithm, a  typical servo control system model was  analyzed and the unbiased least square  method was designed based on  Coulomb friction and viscous friction model.Implementation methods of it were  studied on the hardware of industrial PC and motion control card. Motor angular  speed data was collected in real time. The inertia,viscous friction and  Coulomb torque of system were estimated using the least square method. The validity and the correctness of parameter identification were verified through reconstructing the  angular speed, comparing the actual measurement with theoretical calculation  angular  speed. Theoretical observation and experimental results  show that the parameters of the servo system can be accurately identified in this kind of CNC system platform with the unbiased least square method.

    Improved PSO Layout Optimization Model for Saloon Cabin Driven by Users Decision Making
    Liu Xin, Yu Suihuai, Wang Shuxia, Li Wenhua, Qu Min, Wang Miao
    2016, 27(01):  114-121. 
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    Based on the users' decision making, groups and sequences of facilities position optimization were determined approximately, and facilities optimized determine positions of which were not optimized. The PSO was adapted to develop a new method of saloon cabin layout optimization in 3D. To avoid obtaining partial optimal solutions, an improved PSO by adaptive inertia weight was used and the new method of layout optimization which might be adjusted according to different users' needs was proposed. The different optimized solutions were analyzed and compared to the original one by JACK, the results show the optimization method of the improved PSO is the best one and consistent with ergonomic principles. The method can solve the saloon cabin layout optimization problems effectively.

    Human-machine Cooperative Steering PDC/H∞ Control Strategy Based on Driver Model with Near and Far Visual Angels
    Wang Xuanyao, Wang Qidong, Wang Jinbo
    2016, 27(01):  121-128. 
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    A non-linear road-vehicle and driver-road-vehicle closed-loop T-S fuzzy model was acquired based on a driver model with near and far visual angels. State feedback γ-suboptimum norm and linear matrix inequalities constraint were used to get feedback gain matrix. The global controllers of road-vehicle and driver-road-vehicle closed-loop T-S fuzzy model were designed by using PDC. Simulation results based on CarSim/Simulink show that lane keeping performance and time to line crossing based on human-machine cooperative steering control of driver-road-vehicle closed-loop model are both superior to road-vehicle model, and the lane departure risk is reduced. The man-machine cooperation degree of driver-road-vehicle closed-loop PDC/H∞ controller is higher by evaluation criterion of cooperative steering control.

    Research on Crashworthiness of Minivans Faced on Pole Side Impact
    Lin Zhigui, Lü Juncheng, Luo Qinyue, Jia Ligang
    2016, 27(01):  129-134. 
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    Based on the mechanism of side pole impact, the influences of energy transmission and crashworthiness among minivan and sedan's center of gravity, structure and packaging was compared and analyzed herein. The improvement direction of minivan structure was put forward by the analyses. The simulation of minivan side pole impact and structural optimization was carried out. The results show that crashworthiness performance of minivan is improved significantly, which proves that the optimization methods of minivan side pole impact are feasible.

    Research on Reliability Test for Vehicle Structure Components Based on Road Load
    Wang Tie, Wu Wenchao, Wang Haipei, Wu Wei
    2016, 27(01):  135-141. 
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    A method of programed load spectrum bench test for vehicle structure component was presented, which was based on the theory of equivalent pseudo-fatigue damage between road load and programed load. By Weibull analysis method, the test strategy was developed which reflected the relations among the confidence level, reliability requirements and sample size. For the research of programed bench test for transmission brackets, the failure mode was duplicated, which had the same root cause and fatigue life compared to the failure on road test. By analysing the data of fatigue life of test samples on bench test, the main reasons for impacting the reliability and durability of bracket were discussed. From the results of bench test, it can be proved that the method of programed load spectrum bench test is valid and more efficient.