Table of Content

    25 April 2010, Volume 21 Issue 8
    On-line Measurement of Supporting Characteristics of an Active Magnetic Levitations with Unknown Transfer Function
    JIANG Ke-Jian, CHU Chang-Sheng
    2010, 21(8):  883-888. 
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    A theoretic method for calculating the equivalent stiffness and the equivalent damping of an active magnetic levitation system were analyzed herein.Then,based on the closed-loop control theory,a method was proposed,which can measure the equivalent stiffness and damping without regard to the transfer function of the control system.The experiments,which were used to test the influences of amplitude,frequency and PID parameters on the equivalent stiffness and damping,indicate that the method can correctly identify the equivalent stiffness and damping of active magnetic levitation system in real-time. 
    Measurement Method of Stiffness for Magnetic Bearings 
    WANG Xiao-Guang, GAO Chang-Sheng
    2010, 21(8):  889-892,907. 
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    There exist two different definitions of stiffness in academic study of magnetic bearings.Two definitions of stiffness are different from the aspect of rotor force analysis and control transfer function.In allusion to the two different definitions of stiffness,a measurement method of stiffness for magnetic bearings was given and the experimental measurement system of the magnetic bearing stiffness was designed.The experimental system can measure the stiffness of magnetic bearings when the rotor in all the states of static suspension,rigid rotation and flexible rotation. 
    Study on Drive Motor for Axial-flow Magnetic-levitation Aritficial Heart Pump
    YANG Cheng, LIU Chu-Qin, GUAN Yong
    2010, 21(8):  893-896. 
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    A structural and control method of permanent-magnet slotless brushless DC motor was introduced,which can be used for axial-flow artificial heart pump.ASIC chip ML4425 was used as the central control unit.The speed of the motor can be controlled by changing the input voltage and hence the flux and pressure of blood can also be controlled.The motor has good performance in the artificial heart pump due to the non-contact magnetic bearing. The experimental results indicate that speed of motor can be modulated and has an approximate linear relationship with the input voltage.Moreover,the motor works smoothly with low noise.
    A Review of Unbalance Control Technology of Active Magnetic Bearings 
    ZHANG Ai, ZHANG Xiao-Zhang
    2010, 21(8):  897-903. 
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    A review of the research work performed in unbalance control of rotating machinery supported by active magnetic bearings was presented according to lots of related references.The discussion was focused on the development of unbalance control methods,which are very important for high speed machinery with active magnetic bearings.The advantages and the disadvantages of different methods were analyzed,along with their common places.At last,the further development of unbalance control technology
    was discussed.
    Critical Speed Calculation of Rigid Rotor Supported by AMB
    WANG Hong-Chao, GUO Lei-Lei, MO Li, XU Shuo-Yuan
    2010, 21(8):  904-907. 
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    A simplified method to simulate the AMB rotor was presented based on its design feature.The finite element package Samcef Rotor was employed to create the axisymmetric model of a rigid rotor and obtain the critical speeds and modals.In addition,the relationship between the critical speeds and the bearing stiffness was also analyzed.The numerical results and conclusions can offer an important basis for the arrangement of AMBs and sensors and the design of the AMB control system.
    Measuring Experiments on Construction Static and Dynamic Stiffness of Magnetic Suspension System
    LIU Xiao-Jing, HU Ye-Fa, ZHANG Wei-Wei, WEI Jian
    2010, 21(8):  908-912. 
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    Magnetic plane system construction static stiffness and dynamic stiffness was measured on the basis of stiffness definition by loading poise and sine wave using B&K vibration instrument.After getting data from experiments several curves were drawn including urge frequency—displacement curve, urge frequency—dynamic stiffness curve,force—displacement curve,force—dynamic stiffness curve and the disciplines and features of static and dynamic stiffness were found.By comparing with another experimental results this experiment is verified to be reasonable and correct.It may be as experimental foundation for further research on stiffness theory.
    Research on Temperature Calculation and Cooling System of a High-speed Magnetic Levitation Motor
    WANG Gui-Xiang, XU Long-Xiang, DONG Ji-Yong
    2010, 21(8):  912-916. 
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    For high-speed magnetic levitation motor heating problem,it was established by finite element method of the motor stator heating model,which analyzed the material loss on the impact of motor stator core.Considering the friction of the rotor surface,the wind friction loss of the rotor was calculated.The harmonic currents caused by the rotor eddy current loss in high-speed magnetic levitation motor in the rotor will cause the problem of high temperature rise.The establishment of electromagnetic field equations for solving eddy current loss of rotor was obtained by analysis of the electromagnetic field equations.For the problem of rotor eddy current loss,a harmonic impedance device was used to reduce eddy current loss,which is an effective way to reduce the temperature.The results show that the impedance device can reduce motor harmonic currents and reduce the temperature effectively.
    Study on Equivalent Stiffness of a Flexure Hinge and Its Application in Micro-displacement Compliant Mechanism
    LIU Qiang-Ling, WENG Hai-Shan, QIU Li-Fang
    2010, 21(8):  917-919,925. 
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    The equivalent stiffness k of a variable cross section flexure hinge was researched.The paper presented two methods about calculating the equivalent stiffness k.One was named as the correcting coefficient method, the other was named as variable cross section method. Though examples, the results of the two methods are quiet close to each other and the variable cross section method is simpler and genericer than that of correcting coefficient method. The variable cross section method was used to calculate the equivalent stiffness k of the flexure hinge in compliant micro-displacement amplification mechanism,the compliant mechanism was analysed and the input displacement, output displacement and the amplification ratio were calculated under different forces.The results are contrasted with that of the finite element simulation, the similar results are obtained,which indicates the validity of the variable cross section method.
    Knowledge Supported Classified Constrain Method and Its Application in Product Layout Design
    WANG Pan-Chao, ZHANG Shu-Wei, QIU Le-Miao
    2010, 21(8):  920-925. 
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    To be directed against the problems of products design,a knowledge supported classified constrain method was put forward.This method classified different units of products based on engineering knowledge.Different levels of constrains also had been judged.Knowledge supported classified constraint module was constructed.The customer needs were effectively converted,transfered and calculated,and the product design blueprint was gained automatically.Using this method,an elevator well road layout design system was built.The system had been authenticated when used in the elevator well road layout design.It has solved errors such as human-computer interaction errors,reducing the manufacturing error ratio and development cost as well.
    Modularization Integrated Manufacturing for Installing and Calibrating System of SG-Ⅲ Laser Device
    LI Meng-Ai, XIE Zhi-Jiang, LI Dong-Yang, LIN Zheng
    2010, 21(8):  926-930. 
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    For manufacturing with express, high-quality, a modularization integrated manufacturing model was proposed based on the analysis of system characteristics and functions.The modularization framework for integrated manufacturing was built,and it was described how to create modular decomposition, modular system integration, parallel key technologies such as collaborative manufacturing.The modularization integrated manufacturing approach was applied to the manufacturing of installing and calibrating system for SG-Ⅲ laser device to address the implementation of the system in the process of cleansing, accuracy and efficiency issues. 
    An Analysis Model for Environmental Impact in Manufacturing Process Based on Eco-indicator 99
    GU Zhen-Yu, LIU Fei, LIN Fan
    2010, 21(8):  931-935. 
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    Manufacturing process will produce a wide range of complex environmental impacts. Taking eco-indicator 99 as a reference standard, an analysis model for environmental impact in manufacturing process was presented. Then, the solving processes of the model were described briefly and the environmental impact assessment matrix of a cellular manufacturing process was established. The applicability of this model was demonstrated by an electrical switch cabinet electroplating case. The model can be used to calculate the environmental impact value of manufacturing process which is compatible with the eco-indicator 99. This value can be used to improve the environmental friendliness of manufacturing process and product design programs.
    Analysis and Optimization of Steering Mechanism for Rhombic Vehicle
    CHA Yun-Fei, ZHONG Zhi-Hua, YAN Xiao-Lei
    2010, 21(8):  935-939. 
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    A space kinematics equation of the front wheel’s steering rod mechanism was built through the steering rod mechanism of the rhombic vehicle that was symmetrical about front and rear.The virtual prototyping model was built by utilizing the dynamics analytical software ADAMS of mechanical system.It validated the kinematics equations’ correctness.Considering the length and initial location of the wheel links, the relation of steering angles when the wheel turned left and right was optimized as well as the variation of steering angle during the wheel bounded based on the genetic algorithm.According to the requirements of the rhombic vehicle,the length and initial location of the corresponding links were optimized,which provides a theoretic basis to the design of steering mechanism.
    Fault Diagnosis Approach Study of Bayesian Networks Based on Multi-characteristic Information Fusion
    JIANG Mo-Lu, LIU Sai-Yuan
    2010, 21(8):  940-945,967. 
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    Aiming at the fuzzy and incomplete nature of fault characteristics of axial piston pump,a method of Bayesian networks and multi-characteristic information fusion was proposed.Firstly,multi-fault characteristics in the frequency domain and amplitude domain were extracted from vibration signals and regarded,as multi-source informations coming from different sensors.Then,Bayesian parameter estimation algorithm was applied to fuse multi-characteristic information.Next,the fusion result was simplified by constructing a Bayesian network and establishing Bayesian classifier.Finally,through calculating the maximum posterior probability estimation and the fault patterns were identified.The validity of this method was verified through experiments of multi-fault patterns on an axial piston pump.
    Method of Petri Nets Using T_invariants for Decision-making of Process Sequence Under Process Constraint
    XIAO Wei-Ti, LUO You-Xin, LIAO De-Gang
    2010, 21(8):  946-951. 
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    The decision-making of process sequence in CAPP is the key problems that have not been solved properly until now.A new decision method of process sequence was proposed based to Petri nets using T_invariant.First of all,a Petri net process sequence model based on rule was built according to the principle of Petri net and the production rule.Then,a alternative process plans T-invariant creating algorithm was given considering process constraints.Finally,a case was studied to verify the reason and validity of the algorithm.The results show that the decision-making of process sequence with the proposed method herein can obtain the best/hypo-best process plans in alternative process plans.
    Rolling Bearing Fault Diagnosis Based on MLMW and CWT Gray Moment Vector
    YANG Xian-Yong, ZHOU Xiao-Jun, CHEN Lu, LIN Yong
    2010, 21(8):  951-956. 
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    A fault diagnosis method for rolling bearing was proposed based on MLMW denoised CWT gray moment vector-LSSVM.Sampled signals were denoised by MLMW, and the CWT scalogram of denoised signals was partitioned into several areas, whose gray moment were calculated to form a gray moment vector that was used as the input of LSSVM for fault classification. The experimental results show fault features of MLMW denoised signal’s scalogram is clearer and more distinctive than original,and its gray moment vector can describe bearing condition effectively.With the number of scalogram partitions increasing,the diagnosis accurate rate increases.Compared with diagnosis methods of original gray moment vector-LSSVM and wavelet denoised gray moment vector-LSSVM,the proposed method has higher accuracy,better generalization and requires fewer training samples,and can identify bearing fault patterns accurately.
    Research on Bottleneck Group Scheduling Heuristics for Mass Customization
    CHEN E-Rong, GUAN Zai-Lin, BANG Yun-Fang, SHAO Xin-Yu
    2010, 21(8):  957-962. 
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    By analyzing the characteristics of products and the production in mass customization,we discussed the modular group scheduling problem,and presented a heuristic method for minimizing the weighted tardiness.The method involved the identification of bottleneck operation,and the optimization of both of the production cost and the delivery performance.The results of practice data of an assemble enterprise show,as compared to the modular single scheduling and modular fully-group scheduling,the method presented herein is more feasible and effective.
    Experimental Research on Wire Electrochemical Machining
    SHU Bing, SHU Di, CENG Yong-Ban, WANG Shao-Hua
    2010, 21(8):  963-967. 
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    The feasibility of machining thick stainless steel structures with high aspect ratio by wire electrochemical machining was studied herein.According to the technological characteristics of wire electrochemical machining, electrolyte which flows along the wire electrode was used to carry away reaction products.In order to analyse the influences of processing parameters, we carried out a series of experiments.A micro spline structure which is formed by the groove of 160-micrometer in width on the thick stainless steel,is machined by wire electrochemical machining in the machining system. 
    Analytical Approach to Reliability Based on Two-dimensional Distribution of Loading
    GAO Feng, XIE Li-Yang
    2010, 21(8):  968-973. 
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    By analyzing the statistical properties of random loading,the reliability models of components and systems were developed.Two-dimensional distribution of loading was proposed,including transverse distribution and longitudinal distribution, and reliability models were derived under the two distributions respectively.When using reliability models based on longitudinal distribution of loading,the distribution function of loading at any time is needed.Because of the limit of sample size,the reliability model based on longitudinal distribution of loading cannot be used in practical.The reliability model based on transverse distribution of loading can use the samples directly.By analyzing the relationship between the two distributions, the rationality of reliability models based on transverse distribution of loading is shown.In addition,models of system reliability that are based on transverse distribution of loading were established considering common cause failure.
     An Investigation into Precision Micro-hole Enlargement by Using Electrochemical Grinding
    ZHANG Xin-Yao, SHU Di, CENG Yong-Ban, LIU Yong
    2010, 21(8):  973-977. 
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    Electrochemical grinding was used to machine a precision micro-hole enlargement.And its mechanism was clarified.Then various parameters affecting the accuracy and surface quality in processing,such as voltage,feed rate,rotary speed,were discussed in detail.By optimizing these processing parameters,a high quality micro-hole can be machined successfully on the stainless steel by using a micro electrically conductive diamond grinding tool. 
    Experimental Study on Adaptive Isolation of Periodical Vibration
    WANG Dun-Fang, LI Zhen-Wei, ZHANG Zhi-Yi
    2010, 21(8):  978-982. 
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    For the isolation of multi-tonal vibration at multiple locations,an adaptive isolation method for vibration control was constructed by combing the tracking filtering technique with an anti-saturation LMS algorithm and was further verified with an experiment.The anti-saturation LMS algorithm can prevent any excessive adjustment of controller weights in the case of strong disturbance by introducing an anti-saturation scheme into the traditional LMS algorithm,which can optimize the updating process during the adaptation of controller weights according to the degree of saturation.The experimental results show that the adaptive method is able to suppress the periodical disturbance effectively and to improve the control performance by alleviating output saturation.
    Child Restraint System Parameter Design of a CAR for the Frontal Crash Mode in E-NCAP
    ZHANG Jun-Yuan, BI Ying, ZHOU Jian, QIU Shao-Bei, LI Gong-Jian, TANG Hong-Bin
    2010, 21(8):  983-987. 
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    A study was carried out about the simulation of CRS. Based on the validated model,the CRS dynamics simulation was calculated against to the latest test requirements of E-NCAP.The significant design parameters were optimized based on the E-NCAP assessment.At the same time,the ranges of the parameters and the matching space with the car were proposed according to the engineering feasibility.
    Analysis of Motorcycle Riding Comfort Based on Multi-body Dynamics
    ZHANG Zhi-Fei, XU Zhong-Meng, HE Yan-Song
    2010, 21(8):  988-992. 
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    A modeling method of motorcycle riding comfort was discussed,and the multi-body dynamics software should be used to model in order to reflect seat vibration and hand vibration.The evaluation methods of riding comfort were summarized.The analysis shows that the 2-dof dummy model should be applied while analyzing the riding comfort.The influences of the stiffness and damping of front spring,rear spring and seat cushion were analyzed by orthogonal tests.The seat cushion is the most important for the seat vibration,and the front spring makes a more important effect on seat vibration and hand vibration than the rear spring, the effect of the front spring on seat vibration and hand vibration is not consentaneous. 
    Performance Improvement of Occupant Restraint System Based on Reliability Optimization Method
    LI Tie-Zhu, LI Guang-Yao, GAO Hui, CHEN Chao
    2010, 21(8):  993-999. 
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    Aiming at a minibus,an occupant restraint system of a minibus was modeled and validated using MADYMO software.The text combined with experimental design,Kriging model,reliability theory,a reliability based design optimization method of occupant restraint system was constructed.Comparing with the traditional deterministic optimization results,reliability optimization results meet the established design objectives better,and increase the reliabilities of the design restraints significantly.

    Correlation Analysis of Residual Maximum Main Stress and Vibratory Welding Parameters
    LEI Qiang-Hua, CHEN Li-Gong, NI Chun-Zhen, XU Chi-Shui
    2010, 21(8):  999-1002. 
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    The residual maximum main stress (σmax) of vibratory submerged-arc welding (SAW) under different parameters was studied by means of experiments and mathematical modeling.The results show that when the welding heat input is 22.8kJ/cm,σmax will be reduced evidently as the acceleration increases.The lowest σmax is obtained when the welding heat input is 26kJ/cm and acceleration 10m/s2.While heat input increases to 31.6kJ/cm,σmax distinctivly decreases under the acceleration of 15m/s2.
    The correlation curve of σmax related to heat input residual and acceleration was got through multi-variant nonlinear regression analysis.The optimal vibratory welding parameters were established. Heat input ranged from 22.8~32kJ/cm with acceleration from 10~15m/s2 favors σmax reduction.
    ZHANG Yu, HU Qi-Guo, ZHANG Fu-Ren
    2010, 21(8):  1003-1007. 
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    Aiming at the petroleum perforating charge shell extrusion part,the once extrusion forming process
    was contrasted with the pre-extrusion and final-forming process,and the reasonable process was decided using the pre-stressed combined die.The radial diameter ratio and interference coefficient of the combined die in pre-extrusion and final-forming stage were sampled.The different die structures through sampling were simulated by finite element method,and the Kriging model of effective stress and structure parameters of combined die was established.The structure parameters of combined die in pre-extrusion and final-forming stage were optimized with the objective of decreasing maximum effective stress on the surface of die cavity.The optimum radial diameter ratio and interference coefficient are obtained and the optimum structure parameters of combined die are decided by using particle swarm optimization with Kriging model for global optimization in the variable space. It has provided a basis for the extrusion combined die optimum design.