Loading...

Table of Content

    25 April 2009, Volume 20 Issue 08
    On Upsetting Conditions of Large Forgings without Cylinder Surface Cracking
    Ren Yunlai;Zhu Lei;Nie Shaomin;Li Yuewen
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (3768KB) ( )  
    Related Articles | Metrics

    Instantaneous drum coefficient was given to describe the degree of inhomogeneous deformation during upsetting.The theory of critical hole expansion ratio in damage mechanics was used in the study of cylinder surface cracking.Numerical calculation shows that,with invariable end surface friction condition,the relative pressing volume influences the value of instantaneous drum coefficient.Longitudinal stress and latitude
    stress are as function of instantaneous drum coefficient during upsetting.
    Then,the relation between the stress triaxiality and instantaneous drum coefficient is obtained.By means of the theory of critical hole expansion ratio and plastic equation,upsetting conditions of large forgings without cylinder surface cracking are obtained.The

    Dynamic Modeling and Control on AC Servomechanism
    Zi Bin;Zhu Zhencai;Wei Mingsheng 
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (6012KB) ( )  
    Related Articles | Metrics

    According to the equivalent circuit of the alternating current(AC)
    servomechanism,the dynamic model of the electromechanical coupling system was developed in the presence of internal model uncertainties in both nonlinear friction and servomechanism dynamics and external disturbances.Due to the inherent characteristics of the nonlinear structure, a novel control method combining sliding mode control with fuzzy logic control was designed for the sake of realizing the desired performance of the object.The approach applied fuzzy controller to adjust the parameters of reach law of sliding mode timely.At the same time the exponent approximating control was added by grading. This approach ensures the speediness and robustness of the control system, and can weaken chattering,and the design of the control system is simple and it can be easily applied in the engineering.An example of the servomechanism model on the algorithm was carried out,and its effectiveness and higher robustness were confirmed. 

    Study on Implementation of Boundary Element Method Simulation for Lamb Wave Interaction with Defects in Elastic Plate
    Wang Shen;Huang Songling;Zhao Wei
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (4023KB) ( )  
    Related Articles | Metrics

    Some implementation issues for the hybrid boundary element method program used to simulate Lamb wave interaction with defects in elastic plate were discussed, including basic elastodynamic boundary integration equation and fundamental
    solutions, solving of the coefficient matrix elements for the matrix form system of linear equations, boundary conditions formulation for the virtual boundaries of the model based on mode expansion, calculation accuracy analysis, and some simulation results. This method and the acquired results provide important theoretical basis for Lamb wave plate inspection and can also be used as the foundation of defect quantification algorithm development.

    A Method for Dynamic Locally Weighting Based on Sequential Quadratic Programming 
    Xu Jinghua;Zhang Shuyou;Shen Weiliang
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (4180KB) ( )  
    Related Articles | Metrics

    To realize weighting in motion, a method for dynamic locally weighting based on sequential quadratic programming was put forward. The real-time measured signals were defined as numerical time series of
    measured values and its corresponding symbolic time series of theoretical
    values was solved by taking the moving force and simply supported beam as weighting physical model. The path between the two time series was extended from Euclidean distance path to dynamic time warping path. The recursive computation mathematical model of the dynamic locally weighting was established via taking the minimum of the square of deviance between the two series along the warping path as the goal. The sequential quadratic programming algorithm was employed to obtain the each moving force by means of solving the constrained nonlinear optimization model. The experimental results prove that the computation precision and calculation efficiency of the method are
    favorable enough for the practical requirements.

    Surface Morphology and Material-removal Mechanism 
    in Grinding of Nanostructured Tungsten Carbide
    Ren Yinghui;Zhang Bi,;Zhou Zhixiong 
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (11402KB) ( )  
    Related Articles | Metrics

    This study conducted surface grinding on nanostructured tungsten carbide by diamond wheel under various grinding conditions. Ground workpiece surfaces were observed and measured by scanning electron microscopy and surface profilometry. The study investigated material-removal mechanism and the effect of grinding process parameters, such as grit size and bond type of the diamond wheel, as well as set depth of cut and workpiece feedrate, upon workpiece surface morphology. The study demonstrates
    that the surface roughness increases with the increasing maximum undeformed chip thickness, and is affected by the grit size of the wheel at the same wheel depth of cut; the wheel with resin bond is more appropriate for grinding the nanostructured tungsten carbide; and material removal is accomplished mainly through inelastic deformation.

    Optimal Selection of Attitude Control Points of Shield Machine
    Zhang Xu;Zhu Limin
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (3933KB) ( )  
    Related Articles | Metrics

    Firstly,the error model about measuring points was introduced. Secondly,the linear relation between the measuring errors and the estimation errors of attitude differential motion parameters was established.Thirdly,a metric of attitude precision was defined,which was frame-invariant and scale-invariant and an index of attitude precision. Then,an algorithm for optimally selecting attitude control points was designed using floating search idea. Finally,the algorithm was applied into a shield machine situation. The results show this method can largely decrease the number of measuring points, when the attitude measuring accuracy is known.

    Structural Optimization for High Speed Grinder’s Components Based on the Approximate Model
    Wen Guilin,;Cui Zhong;Peng Keli
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (3890KB) ( )  
    Related Articles | Metrics

    A method for the structural optimization of high
    speed grinder’ components was built,which was based on the approximate model
    and multiobjective optimization.The design variables were the structure dimensions.The radial basis function model was built for the structural optimization based on the design parameters,which were obtained by the Latin square design of experiment.The multiobjective optimization problem was
    resolved by weighted-sum approach and genetic algorithm.The approach was used to optimize the weight and the first frequence of the spindle.In addition,the finite element model of the spindle was built and computed in
    the optimization procedure.The results show that this method can improve the design efficiency of the high speed grinder’ components,and provides the theoretical guides for product design and improvement.

    Simulation of a Free Piston Linear Alternator
    Li Qingfeng;Xiao Jin;Huang Zhen
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (4933KB) ( )  
    Related Articles | Metrics

    The modeling and simulation of a novel development of the free piston linear alternator were presented. The model consisted of two parts, thermodynamics model and dynamics model, and they were combined and solved by MATLAB/Simulink respectively. The effect of intake pressure, moving mass, ignition position and resistance loads was studied. The simulation results show that the free piston motion is different from the traditional internal combustion engine (ICE). The free piston accelerates and decelerates more quickly at the end of the stroke. Besides, the top dead center is free and changes with these parameters accordingly. The high compression ratio can be achieved easily. The built model provides a foundation for the design and improvement for free piston linear alternator.

    Research on Hybrid Ceramic-Metallic Internal Grinding Wheel Spindle
    Wang Jun;Zhang Sheng;Guo Xue;Li Hongjun
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (4336KB) ( )  
    Related Articles | Metrics

    In order to improve the static and dynamic performances,a hybrid ceramic-metallic internal grinding wheel spindle was developed. FEM-analysis and performance test were made to investigate the new develeped and traditional grinding wheel
    spindles.The results have proved that the performances of hybrid ceramic-metallic internal grinding wheel spindle are obviously better as compared with now available grinding wheel spindles. Internal grinding speed can be increased by using the new grinding wheel spindle.

    Research on Orientation of Mobile Manipulator 
    End-effector Based on Multi-Source Information Fusion 
    Ding Chengjun;Duan Ping;Sui Bailong;Zhang Minglu
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (5454KB) ( )  
    Related Articles | Metrics

    This paper adopted HEBUT-Ⅱ mobile manipulator as the research object, which was used for leak detecting and repairing for dangerous chemical reactor.We researched the orientation of mobile manipulator end-effector based on multi-source information fusion, realizing the fusion of vision and ultrasonic information, finally, the results were applied at the precision orientation of manipulator end-effector.The orientation equipment included vision system and ultrasonic sensor, thereinto, the vision system was used to generate a
    2-dimensional image that was prone to be recognised and understood by the computer, at the same time, the third information, that was the distance between the end of manipulator and the operated surface was provided by ultrasonic sensor.Examinations make known that the method can fastly and truly pick-up the information of leakage location and do some work for the next task-gushing glue and blocking up the leak.

    Physiological Gait Planning and Testing for a Lower Limb Gait Orthosis
    Wang Qiyuan;Qian Jinwu;Feng Zhiguo;Shen Linyong ; Zhang Yanan
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (5187KB) ( )  
    Related Articles | Metrics

    By detecting the walking motion trajectories of normal subjects’ lower limbs using a motion capture system, the hip joint and knee joint angle data
    were obtained and a human physiological gait database was established. Based on the hip joint and knee joint angle data, the physiological gait planning for a lower limb gait orthosis, which was used for the gait rehabilitation, was made. The planned physiological gaits were tested on the experimental prototype. Experimental results show that the experimental prototype is able to guide the patient’s legs to walk in a physiological gait pattern according to the planned physiological gait, and the gait trajectories are smooth and continuous.

    Measurement Method and Experimental Research on Dynamic Force Behavior of Bottom Drill String
    Li Cheng;Ding Tianhuai;Wang Peng;Chen Ken
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (4089KB) ( )  
    Related Articles | Metrics

    A straight beam strain gauge sensor and a virtual instrument-based dynamic force wireless measurement device of simulated drill strings were developed to study the near-bit bottom drill string dynamics in measurement while drilling.The structure and working principle of the measurement system were expressed. The axial forces, radial forces and torsional moments for rotating simulated drill string were detected multithreadedly in the laboratory.And the solutions of lateral resultant forces were achieved.By using bottom-hole assembly (BHA) composed of simulated drill strings,the dynamic force parameters of BHA were measured under different weight on bit(WOB) loads and deviation angles.Moreover,the variational law of lateral forces was analyzed.The results show that the developed system can perform on-line measurements in the laboratory and provide experimental basis for the theoretical analyses of the hole deviation control mechanism of BHA.

    Novel Photothermal Microactuator and Its Microscopic Motion Measurement
    Chen Chao;Zhang Dongxian;Liu Chao;Zhang Haijun
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (4285KB) ( )  
    Related Articles | Metrics

    A new type of photothermal microactuator (PTMA) was developed and its microscopic motion measurement method was presented. A 1.5mm-length asymmetric PTMA was designed and micro-manufactured. Using the microscopic motion measurement method, the amplitude and frequency of the PTMA were measured and analyzed under
    the control of 650nm/9mW laser. The maximum amplitude was measured to be 10.3μm,while the response frequency was between 0~7Hz.The motion lotus was also plotted. The results indicate that such a PTMA is capable of generating micro-motion with different amplitude (displacement) and different frequency (speed), providing a novel micro-actuating method for micro electromechanical system(MEMS).

    Research on the Interference Assembly Based on Surface Digital Model
    Liu Baoqing;Dong Huimin
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (6309KB) ( )  
    Related Articles | Metrics

    A new approach to representation of interference’s quantity in practice was presented by means of interference volume, which was calculated accurately based on surface digital model. Firstly the surface digital model was established according to spline function and discrete data measured by three coordinates measuring machine. Then, the calculation method and the correction method of interference volume were discussed.Finally, this approach is profitable to actual assembly guiding,which will be readily seen from the example given herein.

    EDM of Oil Supply Tank with Multi-curvature and Design of Accurate Assembly Electrode
    Wen Wu;Wang Xibin;Long Zhenhai; Zhu Chaoyang
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (3823KB) ( )  
    Related Articles | Metrics

    EDM of oil supply tank of some equipment with copper electrode and graphite electrode was tested,the processing characteristics in the EDM of QT700-2 were analyzed,through contrasts among processing speed, electrode wear ratio, machining gap and surface quality etc,a suitable electrode material and process parameters were selected.The characteristics of accurate assembly electrode EDM oil supply were analyzed,the results suggest that:the copper is more suitable than others electrode material in the EDM of QT700-2 according to experiments.Integrated theory with practice,an accurate assembly electrode was worked out and manufactured,and the parts that made by EDM with accurate assembly electrode have met the requirements of design.

    Coarse-grain Authorization of Manufacturing Grid Node Based on Trust
    Xiong Feng;Cai Hongxia;Liu Lilan;Wang Chen
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (4299KB) ( )  
    Related Articles | Metrics

    In order to ensure the security of the sharing service in the manufacturing grid, an coarse-grain authorization mechanism based on the trust was presented to realize the automatical authorization of sharing services in the manufacturing grid node. In this mechanism, it was based on the trust that the service providers authorize the sharing services to the virtual organizations(VO) or the other nodes. The trust evaluation function calculated the trust degree between the entities. The lowest trust degree which was allowed to access the sharing servce was set in the auhtorization policies. The access subjects could access the sharing service if the trust degree of the access subject was higher than the allowed trust degree in the coarse-grain access control policy. A case study and algorithm simulation was presented to verify this mechanism could enhance the access contorl of the sharing service in the manfacturing grid.

    Research on the Proliferated Process Adjusting Model Based on Workflow
    Liu Jiaojian;Liao Wenhe;Guo Yu;Yu Feng
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (4241KB) ( )  
    Related Articles | Metrics

    In the mode of rapid proliferating manufacturing, in order to control the procedure of process adjustment strictly and efficiently, and ensure the stable quality of proliferated parts, the procedure of rapid process proliferation was studied, the process adjusting model was built based on workflow technology,and the method of adjusting influence analysis was put forward. A prototype system was also developed. Through the implementation in an aerospace enterprise, this system shortenes the adjusting time, improves production efficiency and reduces the cost effectively.

    Research on the NURBS Curve Fitting for Tool Path Generation
    Yang Xujing;Hu Zhongxun;Zhong Zhihua
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (5871KB) ( )  
    Related Articles | Metrics

    A new approach was proposed to fit the cutter locations with NURBS curve for generating NURBS tool paths. The algorithm used a new high precision fitting method to fit the tool paths through the cutter locations more precisely with fewer control points. Thus a NURBS tool path with higher accuracy and more concise program
    could be generated.Examples of sculptured surface were designed and the NURBS tool paths were generated.The application results demonstrate the advantages of the approach,and satisfactory to the high performance CNC requirements. 

    A Low Cost Kinematics Calibration of Parallel Robots
    Liu Wei,;Zhao Jianbo;Gao Feng;Qi Kaicheng,
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (4883KB) ( )  
    Related Articles | Metrics

    A low cost kinematics calibration for the general precision parallel robot was proposed.This method was easy to handle without the pose information measured by the valuable apparatus.To specify this
    method,a calibration model of a 6-DOF parallel simulator was set up,which set the relation between the displacement errors in single direction of six target balls and the pose residuals of the end-effector. With this model, the parameters of the parallel robot can be identified with the displacement data measured by the deformed vernier calipers. The digital simulation demonstrates theoretically that the calibration precision of the this method is similar with that of the conventional calibration algorithm.Finally, the influence of the measurementing errors and the positioning errors on the calibration was analyzed.

    Investigation for Wire Electrochemical Machining of Micro Grooves
    Wang Shaohua;Zhu Di;Qu Ningsong;Wang Kun
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (9562KB) ( )  
    Related Articles | Metrics

    Wire electrochemical micro-machining uses a tungsten wire as the tool electrode.Based on electrochemical principle,the mechanism of wire electrochemical micro-machining was investigated. Changes in the machining gap according to diameter of the wire, electrolytes, voltage, feed rates were investigated, and the optimal processing parameters for stable machining were obtained. By using this method,a micro groove of 30μm in width is fabricated on 0Cr18Ni9 sheet.

    Study on Real-time Control System of Gasoline HCCI Engine
    Zhou Nenghui ;Xie Hui;Zhao Hua ;Chen Tao 
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (4297KB) ( )  
    References | Related Articles | Metrics

    Homogeneous charge compression ignition(HCCI) combustion is gradually becoming a new combustion mode. However, it is still confronted with problems in real-time control and control system. A CAN-bus-based distributed HCCI control system was designed to obtain closed loop control on HCCI gasoline engine in order to ensure real-time control. Meanwhile, a layered management strategy was developed to achieve highly real-time control as well as to simplify the couplings between the inputs and the outputs. The entire control system was stratified into three layers, responsible for load management, combustion phase control and mechanical system control respectively, each with its own specified closed loop control strategy. The system is outstanding for its explicit configuration, easy actualization and robust performance. The experimental results show that, with the layered management strategy and control system applied, real-time control over HCCI operation becomes possible.

    Feasibility Study of Hybrid Processing of Laser Beam Machining Combined with Jet Electrochemical Machining
    Zhang Hua,;Xu Jiawen,;Wang Jiming;Yuan Lixin,
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (6869KB) ( )  
    References | Related Articles | Metrics

    In order to solve the Achilles’ heel with recast layers produced during laser beam machining, a new hybrid processing of jet electrochemical machining and laser beam machining (JECM-LBM) was put forward and had been studied fundamentally.The special experimental equipment was designed and made based on the study on the properties of laser attenuation in electrolyte, and drilling experiments on the thin stainless steel were tested with the equipment.It is confirmed that JECM-LBM is feasible by the comparing results of JECM-LBM with laser beam machining in air (LBM) and jet-assisted laser beam machining(Jet-LBM).

    Markov Chain Simulation Based Line Sampling Method for Reliability Sensitivity
    He Hongni;Lü Zhenzhou
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (3929KB) ( )  
    Related Articles | Metrics

    For reliability sensitivity analysis of implicit non-linear limit function with high dimensionality and small failure probability, which is difficult to be solved in engineering,a novel line sampling method was presented on the basis of Markov chain simulation. In the presented method, Markov chain simulation was employed to generate samples in failure domain rapidly. These failure samples were used to determine the important direction, and they were also used as samples of the line sampling for estimation of the reliability sensitivity. After the concept and the implementation of the presented method
    were explained, the variance of the reliability sensitivity estimation was analyzed approximately.At last, several examples were given to demonstrate the presented method. The results of the examples show that the presented method is valid for calculating the reliability sensitivity with high precision and high efficiency. 

    Displacement Analysis of Stator of Electromechanical Integrated Toroidal Drive
    Zheng Dazhou;Xu Lizhong
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (5119KB) ( )  
    Related Articles | Metrics

    This paper mainly concentrated on the system of electromechanical integrated toroidal drive and the principles of integration. With more details on the complicated mechanics analysis of the spatial helical stator and, in addition,based on the coordinate transforming principle, equations of the stator were deduced. Derived from the relationship between the stator coordinate and the section coordinate that was given,the equation of potential energy was obtained. Consequently, with the support from the minimizing energy method, the results of displacement distribution of the stator at different meshing points were determined as well as the rules were analyzed simultaneously. Such results are useful for intensity and rigidity design of electromechanical integrated toroidal drive and for stability analysis of the stator as well.

    Satisfaction Evaluation Method of Multidisciplinary Design Optimization Based on Analytic Hierarchy Process
    Zhang Jing;Li Bailin;Liu Yongjun
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (3933KB) ( )  
    Related Articles | Metrics

    In order to perfect the theory of multidisciplinary design optimization, the evaluation problem of feasible solution was researched. Firstly, the weights of disciplines were calculated.Secondly, the satisfaction evaluation model of MDO systems and the evaluation method were established and proposed respectively. At last,feeding manipulator was selected as an illustrative example, and the validation results indicate that the presented method can evaluate the MDO systems, and offer guidance for further design.

    Numerical Modeling and Calculation for Tubular Radiation Heater of SLS System
    Guo Kaibo;Chen Liping;Shi Yusheng;Huang Xiaomao
    2009, 20(08):  0-1007. 
    Asbtract ( )   PDF (3796KB) ( )  
    Related Articles | Metrics

    a mathematic model was built for the tubular radiation heater of the HRPS series SLS systems. The mathematic calculations were used to obtain the thermal distribution from the radiant heater in the work field and the curve diagrams of evenness degree at the different heights, so the optimal mounting height of the radiant heater was achieved.The analysis method can be well used for reference to develop advanced heater with homogeneous energy distribution.

    Study on Performance Characteristics of Sodium Silicate Sand Hardened by Superfines
    Wang Jina;Fan Zitian;Zan Xiaolei
    2009, 20(08):  0-886. 
    Asbtract ( )   PDF (7561KB) ( )  
    Related Articles | Metrics

    The performance characteristics of sodium silicate sand hardened by superfines were studied, and it was compared with the performance of sodium silicate sand hardened by ester, which was adopted widely in the foundry enterprises at present. The microstructure of sand samples hardened by ultrafines or ester, including the sand samples at room temperature and roasted at 800℃,was observed by SEM.The results show that the room temperature strength of the sand samples hardened by ultrafines is increased about 23% and the residual strength is reduced about 76% to the sand samples hardened by ester.In the ultrafines hardening process, the added quantity of sodium silicate is 3% and the added quantity of ultrafines is 25% of the added quantity of sodium silicate. The sodium silicate sand hardened by ultrafines is not sensitive to the module of the sodium silicate. In the hardening process, using high module sodium silicate can
    improve significantly the collapsibility and reclamation performance of the sand. The moisture resistance of the sodium silicate sand hardened by ultrafines is better than that of the sodium silicate sand hardened by ester.

    Theoretical and Experimental Research on the 
    Spread of the Head of Rail in Rail Rolling by a Universal Mill
    Dong Yonggang;Zhang Wenzhi;Song Jianfeng
    2009, 20(08):  0-1003. 
    Asbtract ( )   PDF (4618KB) ( )  
    Related Articles | Metrics

    For obtaining the spread law of the head of rail in rail rolling by a universal mill, the deformation mechanism of rail rolling was studied thoroughly, and the deformation concordant coefficient and material’s influence coefficient were applied in correcting the Smirnov spread formula.For verifying the theoretical model, the universal rolling process of 18kg/m light rail was simulated by rigid-plastic FEM.Moreover, the universal rolling experiments were accomplished in the Rolling Laboratory of Yanshan University and the spread values of the head of rail subject to different rolling technology were measured.Compared with the simulation results and the measured results, the corrected spread formula is accurate enough and its calculation results approaches the measuring results more than that of original spread formula.So, it is reliable and feasible to predict the spread of the head of rail in rail universal rolling and preset the rolling technology rationally according to this corrected spread formula.