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Table of Content

    25 March 2009, Volume 20 Issue 06
    An Experimental Investigation and Simulation of Rotational Fretting
    Mo Jiliang;Zhu Minhao;Liao Zhengjun;Yao Chongyue;Zhou Zhongrong
    2009, 20(06):  0-635. 
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    Rotational fretting tests in a configuration of ball-on-flat were successfully realized by developing a new fretting device based on an ultra-low-speed reciprocating rotational driver. The rotational fretting tests of LZ50 steel flats against GCr15 steel balls were performed under different testing parameters. The results show that the rotational fretting behavior of the LZ50 is strongly dependent upon the angular displacement amplitude and the normal load. Friction force-angular displacement (Ft-θ) curves can be used to characterize the rotational fretting running behavior, which exhibits three basic types of the parallelogram, elliptical and linear cycles by varying the angular displacement amplitudes or the normal loads. The rotational fretting is characterized by elastic deformation coordination at the contact interface when run in the regime of partial slip. With the increase of the angular displacement amplitude and the decrease of normal load, the fretting running state transfers from the partial slip to the gross slip. The micro-examinations indicate that the plastic deformation, abrasive wear, oxidative wear and delamination are the main damage mechanism for LZ50 steel under the gross slip conditions. A special phenomenon which is different from that observed in the tests of the normal reciprocating fretting(tangential fretting), i.e. wear debris generated is accumulated in the centre zone of the wear scar under the condition of gross slip, is observed and analyzed herein.

    A New Type Frictional Transducer
    Li Renjun;Liu Hongzhao;Wang Zhongmin;Li Pengfei
    2009, 20(06):  0-635. 
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    A new type frictional transducer was designed by assembling two flexure hinges and two uniform cantilever beams.The influence of friction and reversal clearance which existed in the parts of traditional sensors were avoided, and the continuous measure of friction factor was realized.The expression of interaction between normal force and friction was deduced on theory of structural mechanics.The structure of transducer was optimized if the part sizes of the sensor were given, and therefore the coupling of normal force and friction was eliminated.The flow chart for design the sensor was presented.The results of simulation prove the availability of the sensor.

    Beam Attenuation Grid-based Scatter Correction Method for Cone Beam CT
    Zhang Dinghua;Hu Dongcai;Huang Kuidong;Kong Yongmao
    2009, 20(06):  0-673. 
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    Ministry of Education,Northwestern Polytechnical University,Xi’an,710072
    Aiming at the scatter artifact in the cone beam CT system,we proposed a new scatter correction method that needed to add a beam attenuation grid between the X-ray source and the tested object.This study described about how to calculate the scatter value of the projection position of the center of each steel ball in the beam attenuation grid.Then,employing the spatial cubic spline interpolation on these values,we can get the scatter distribution image.Lastly,subtracting the scatter distribution image from the original projection image,we can acquire the scatter corrected projection images of the tested object.In order to improve the feasibility of this method,we did many experiments on the cylinder sample and the crescent sample.The results show that the method can obviously reduce the cupping artifact and increase the image contrast of the reconstructed slice image.

    Study and Simulation of Dynamics of a 7-DOF Flexible Wheeled Mobile
    Manipulator
    Yang Yuwei;Zhang Minglu;Zhao Xinhua
    2009, 20(06):  0-635. 
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    This paper studied the kinematics and dynamics of
    a 7-DOF flexible wheeled mobile manipulator.And the flexible wheeled mobile manipulator consisted of a mobile base with a 2-DOF linear elastic suspension system and a 5-DOF flexible manipulator.The assumption was given that the flexible wheeled mobile manipulator moved with a constant velocity over the uneven road surface that could be described in terms of sine wave.The symtem dynamics model of the flexible wheeled mobile manipulator was derived in terms of Cartesin coordinates based on both Lagrangin dynamics equations and general Newton-Euler ones and described compactly with matrixes and vectors.And the symtem dynamics model included the system dynamics coupling interaction,which came from the elastic deformation of fexible manipulator and movement of the suspension symtem.At last,the numerical simulation was carried out based on the forward dynamics model of both the flexible manipulator and the rigid one.And these simulation results illustrate the coulpling effects.

    Three-dimensional Material Removal Model of Magnetorheological Finishing(MRF)
    Shi Feng;Dai Yifan;Peng Xiaoqiang;Song Ci
    2009, 20(06):  0-673. 
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    In magnetorheological finishing(MRF) process,the magnetorheological(MR) fluid was set into the gap between the rotation wheel and the work piece suraface and a MR fluid seal was formed by the magnetic field. Then, in the contact zone, high shear stress and press force was distributed and some materials were removed over the work piece surface. Considering the mechanism of material removal in MRF process, shear stress controlled and press force assisted, an associated coefficient surface was cauculated. A 3D material removal model of magnetorheological finishing process was established. The comparison between the simulation results and experimental ones supports to the model.

    Study on the Technologies of Rapid Three-dimensional Optical Measurement and Modeling for Large Airplane
    Liang Jin;Xiao Zhenzhong;Liu Jianwei ;Liang Xinhe
    2009, 20(06):  0-635. 
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    A rapid three-dimensional optical measurement system for large airplane was proposed,which was composed of XJTUDP digital close-range industrial photogrammetry system and XJTUOM optical 3D range scanning and measurement
    system.The XJTUDP system was based on digital close range photogrammetry.The XJTUOM system was based on heterodyne multiple frequency phase shift technology.Through the use of circular coded targets, it first located the positions of the camera automatically.Then camera self-calibration was applied by using the bundle adjustment algorithm to optimize the initial values.Last the matching and reconstruction of the uncoded targets
    were resolved throughout the epipolar geometry of multiple positions of the camera.The normal vector of the targets was used to eliminate the errors from thickness of targets. Some experimental results show that the error of XJTUDP system is less than 0.01mm,the error of XJTUOM system is 0.02mm, and can be measured for the 50m large airplane.

    Experimental Research on the Static Characteristics of 
    Water Hydraulic Servo Valve Caused by Fixed Damp Orifice
    Li Ruping;Nie Songlin;Yi Menglin
    2009, 20(06):  0-673. 
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    With experimental research method,this paper investigated the effects about static characteristics of water hydraulic servo valve caused by fixed damper orifice,the static characteristics including mainly interior leakage characteristics on zero location,non-loading flux characteristics,loading flux characteristics and pressure characteristics etc.The experimental result is that static characteristics of water hydraulic servo valve is nice when the diameters of the two stage fixed damper orifices are similar.The machining error of fixed damper orifices will make damp characteristics non-symmetry,it will also change the symmetry of water hydraulic servo valve worse.

    A New Accurately Modeling Method for Complex Globoidal Indexing Cam
    Cong Ming;Liu Jing;Li Quanpu
    2009, 20(06):  0-635. 
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    Based on converse thinking,a new modeling method was presented in allusion to the fact that the modeling and manufacturing of complex globoidal indexing cam were difficult.The theoretical profile equations of globoidal indexing cam were derived with the application of conjugate surface theory,differential geometry,and coordinate transformation principle. The principle of the new modeling method was analyzed.Theoretical profiles were built
    up on the blank model of globoidal indexing cam combined with movement laws of driven turret and working profiles were obtained by normal offset of the theoretical profiles and solid cutting operation.Therefore,the accurate model of globoidal indexing cam was finished.A modeling example of the complex multihead globoidal indexing cam used in automatic tool changer of NC machining center was carried out by this method and the kinematics simulation was presented.The result is agree with the design requirements,showing validity and feasibility of the method.

    Research on Structural Characteristics of Lower-mobility Parallel Robots
    Huang Yonggang;Huang Maolin;Du Li
    2009, 20(06):  0-673. 
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    Based upon screw theory and set theory, the structural characteristics of lower-mobility parallel robots was studied via the union of limb constraints and the coupling of loop over-constraint. The quantity relationship of over-constraints between basic loops and whole mechanism was obtained and the concepts of all-loop over-constraint multi-loop over-constraint and single-loop over-constraint was provided. Finally, the effects of over-constraint on lower-mobility parallel robots were discussed, the application of structural characteristics was also introduced briefly.This provides a new point of view and approach to the structure synthesis and optimization.

    Modeling and Controller Design of Piezopositioning Stage for High Speed Dynamic Positioning
    Zhang Dong;Zhang Chengjin;Wei Qiang,
    2009, 20(06):  0-635. 
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    In order to realize piezopositioning stage’s dynamic positioning with high speed and high accuracy,dynamic positioning modeling and the controller
    design were studied. Through theoretical analysis the dynamic hysteresis model structure of piezopositioning stage and its parameter identification way were proposed. Furthermore, the dynamic hysteresis model composed of Prandtl-Ishlinskii (PI) hysteresis operator was given and an open loop controller was designed. Some experiments on the piezopositioning stage of a scanning electrochemistry microscope elaborated the building process of the dynamic hsyteresis model, then the hardware-in-the-loop simulation of the open loop controller was made. Experimental results indicate that the mean error of dynamic hysteresis model is 0.11μm and the mean tracking error of the open loop controller is 0.12μm, which satisfies the high accuracy requirements when the stage positioning at high speed. 

    Dynamics Modeling of Nipper Mechanism on Comber with Non-linear Finite Element Method
    Zhao Chunhua;Tang Wencheng;Wang Rong
    2009, 20(06):  0-673. 
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    To get a valid dynamics model of nipper mechanism on comber,which determined its dynamic response,the shear deformation,tension-compression deformation,and bending deformation were considered in strain energy.Non-linear factors were retained,including the quartic term of displacement gradient,the cubic term of coupled displacement gradient,and shear deformation,and their effects on dynamic response were studied closely.Comparing to linear approaches in the low-speed range,it is found that the dynamic responses predicted by all approaches make no significant difference,however,in the high-speed range,the approach neglecting the quartic term overestimates the vibration amplitude more than 8-fold and the approach ignoring shear strain underestimates the vibration amplitude almost 3-fold.Therefore,non-linear finite element formulation taking into account the quartic term and shear strain is needed in analyzing high-speed nipper mechanism on comber.

    System Model of Modern Job Shop Operation Information and Case Study
    Liu Fei ;Ren Fan;Wang Dongqiang
    2009, 20(06):  0-635. 
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    Based on the existing achievements and researches on operation information in job shop,a six-layer-structural system model of modern job shop operation information was proposed,including job shop operation objective layer,requirement information layer,information source main line layer,information content and category layer,information collecting layer and information processing layer.This model supports the optimal operation work,and is lined with multi-task process and multi-equipment process.Furthermore,the system characteristics of the system model including hierarchy structure,category and compound supporting were discussed.The case study shows that the system model is practical in improving the response ability and implementing green manufacturing.

    Numerical Simulation on the Movement of an Improved Amphibious Vehicle in Small Regular Waves
    Gao Fudong;Pan Cunyun;Jiang Lehua
    2009, 20(06):  0-673. 
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    The motion equations of the amphibious vehicles were established with considering the dynamic lift force and the pitch and the heave motion of an improved amphibious vehicle in small regular waves was computed according to the movement characteristics of the vehicle in the waves. Then the FLUENT software was used to simulate the amphibious vehicle’ ambient flow field through defining the unsteady boundary condition. The lift, resistance, velocity, pressure, and wave of the amphibious vehicle moving in the regular waves were obtained, which can avoid the errors resulted from neglecting the free surface and provides theoretic basis for the research on optimization design of high performance amphibious vehicle.

    Mesh Blending Approach Based on Bi-directional Zipper Method 
    Cheng Xiaosheng;Yuan Tianran;Dai Ning 
    2009, 20(06):  0-635. 
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    A novel mesh blending approach was proposed,which can blend different triangle meshes according to the boundary conditions flexibly and intuitively.It was mainly composed of the following steps:(1) triangulated boundaries of the triangle meshes to be blended as the way of bi-directional zipper working, and got a coarse blending mesh patch in which the triangle was simply the connections between vertices of boundaries;(2)refined the coarse blending mesh patch according to the meshes’ boundaries density,and also relaxed interior edges when refining to maintain a Delaunay-like triangulation,after refining and relaxing,we got an optimized blending mesh patch;
    (3)interpolated the boundaries constraints and their corresponding normal constraints by a smooth implicit surface based on radial basis functions.Using Newton’s iteration method, the optimized blending mesh patch’s vertices were mapped onto the corresponding points in the implicit surface, and the final blending mesh patches were obtained,which smoothly and continuously fitting across the boundaries.The effectiveness of the proposed method was tested and proved in many experiments of different kinds of boundaries conditions. 

    Research and Development of CAI System Based on Standard Solutions
    Yang Bojun;Tian Yumei;Tan Runhua;Ma Jianhong
    2009, 20(06):  0-673. 
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    The application process and the existing arithmetics of
    standard solutions in the innovation design were discussed, then the arithmetic and the flow of software that are suitable for the CAI system were constructed.With the support framework of knowledge database, the arithmetic integrated the substance-field(Su-F) analysis tool which was applied to model a technical or process problem with standard solutions tool, implemented to acquire a solution. During the development of CAI software product, static models built based on UML were used to construct the configuration of system, and dynamic models were used to describe the behaviors of system components, then achieved software system analysis. The standard solutions CAI software was coded with VC++ and XML+XSL,which have friendly interfaces and can be used convenientlly.Under the help of this software, the component of a roller in the Chinese traditional medicine dropping pill packing is improved.

    Product Disassembly Sequence Planning Based on Improved Genetic Algorithm
    Wu Hao;Zuo Hongfu
    2009, 20(06):  0-635. 
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    To solve product disassembly sequence planning problem efficiently,product disassembly hybrid graph model,which described the connection,non-connection and precedence relationships between the product parts,was established based on the characteristics of disassembly.All the feasible disassembly sequence was obtained through inference method.Further,the optimization model was provided to optimize disassembly sequence.And the solution methodology based on genetic algorithm with binary-tree algorithm was given out.Finally,an example was analyzed in detail,and the result shows that the model is correct and efficient.

    Systematic Analysis on Associated Factors between Product Innovation and Process Innovation Based on Manufacturing Industry
    Chen Shen,;Bi Kexin,;Gao Wei
    2009, 20(06):  0-673. 
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    In the view of a system, this paper studied on the synergetic development between product innovation and process innovation and its effect on activities of product innovation and process innovation in manufacturing enterprises.Then associated factors between product innovation and process innovation were found.On the basis of above, the system composed by associated factors between product innovation and process innovation was a grey system and was analyzed by the method of grey relating analysis based on grey system theory. A detailed analysis of the system was described.It is obtained that the result of the importance degree of associated factors between product innovation and process innovation of manufacturing enterprises by grey relating analysis.

    Particle Flow Simulation on the “Trap” Effect of Semi-fixed Abrasive Plate
    Yuan Julong,;Wang Zhiwei;Qian Miao;Hong Tao
    2009, 20(06):  0-635. 
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    A particle flow model of semi-fixed abrasive plate (SAP) was developed with PFC(particle flow code),in which the holding power of the bond to the abrasive grains was described by the parallel bond behavior.The parameters of the particle flow model were obtained by experimental tests of compression ratio of SAP samples.The
    “trap” effect of one large grain was simulated,and evaluated by tow dimensionless parameters of the falling depth of the large grain into the plate and the normal force of the large grain on the workpiece.The effects of bond strength,load,and the size of large grain were analyzed,and the results show that low bond strength,high load or small size of large grain tend to improve the “trap” effect.

    Study on 3-D Turbulence Numerical Simulation and Wear Characteristics of Slurry Pump
    Wu Bo;Yan Hongzhi1;Duan Yiqun2;
    2009, 20(06):  0-662. 
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    A 3D numerical simulation of solid-liquid two-phase flow in centrifugal pump was performed based on SIMPLEC algorithm.Relative velocity,concentration and wall shear stress of solid particle on wall of slurry pump were computed.The results show that relative velocity and concentration on blade and backboard increase along with solid particle diameter.For casing,concentration increases along with solid particle diameter,but relative velocity decreases.Pump wear characteristics are affected obviously by parameters of the impeller blade.

    Research on the Polishing of Silicon Wafer by Fixed Abrasive Pad
    Zhu Yongwei;Wang Jun;Li Jun;Lin Kui
    2009, 20(06):  0-635. 
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    Analytic scales and pencil hardness tester were employed to analyze the effect of the composition of pad on its swelling ration and hardness. The average surface roughness of wafers polished by fixed abrasive pad(FAP) and conventional pad was compared. Results show that the swelling ratio of FAP rises with the increase of the content of polyethylene glycol diacrylate(PEGDA) or ethoxylated trimethylopropane triacrrylate(EO15-TMAPTA). The dry pencil hardness of FAP increases with the increase of the content of EO15-TMAPTA, while it first increases, then decreases with the increase of the content of PEGDA. Its wet pencil hardness improves increasing the content of PEGDA or EO15-TMAPTA. The photo initiator is helpful to improve its wet and dry pencil hardness. The material removal rate polished with FAP is two or three times as much as that polished with conventional polishing, while the average surface roughness Ra of silicon wafer polished by FAP reaches 12.2nm, and is worse that the latter whose Ra is 4.32nm.

    Study on Combination Control of Deploy Process of Large Space Deployable Antenna
    Wang Juan;Liu Mingzhi;Zhao Yuejing
    2009, 20(06):  0-662. 
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    Aimming at the control problems of the deploy process for a
    large space deployable antenna, the system was separated into slow change sub-systems and fast change sub-system based on the singular perturbation method.The combined control method was present,which combined non-linear PID control and H∞ robust control.The non-linear PID controller was designed for the slow sub-system to control the rigid moment to track the expect track,while H∞ controller was designed for the fast sub-system to constrain the flexible vibration, which can guarantee the export of rigid and flexible state can satisfy the requirements simultaneity.Simulation results show that this method can minish the infection of elastic vabiration to the noumenon monment, the antenna can track the expect track to deploy, the elastic vibration is constraind simultaneity, the capability of track and stability of the system is improved markedly.

    Research on Microstructure of GH163 Super Alloy Part Directly Manufactured by PDM
    Xiong Xinhong;Zhang Hai’ou;Luo Jixiang;Wang Guilan;Xu Jipeng
    2009, 20(06):  0-635. 
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    A variety of analytical tools was used to analyze the microstructure and the phases of GH163 super-alloy parts directly made by plasma deposition manufacturing(PDM) herein. According to the crystal growth theory of metal solidification process,the GH163 super-alloy components fabricated and the segregation process were characterized in terms of PDM process and vacuum precision investment casting process.GH163 super-alloy parts formed by PDM possess a rapid solidification process and are of perfectly fine and dense microstructure with unique composition uniformity and minimal segregation compared with the casting process.

    Application of Solid Element in Ironing Simulation and Optimization of
    Processing Parameters 
    Xu Jiangping;Liu Yuqi ;Du Ting;Zhang Zhibing
    2009, 20(06):  0-662. 
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    Based on viscosity damping hourglass control method,a one-point integrational hexahedral finite element dynamic explicit algorithm was developed and ironing process simulation was also carried out. The thinning coefficient R,friction coefficient μ between molds and blank, cone angle of female die α,which affected
    the maximum forming force, were discussed in details. Simulation results show that the improvement and choice of the process parameters R,α and μ can obtain
    smaller maximum load force, thus effectively decrease molds wear and lengthen molds life.

    Structure Optimization Design for Pin Round Punch Based on FEA
    Wang Kesheng,;Liu Quankun;Sun Xianping; Wang Leigang
    2009, 20(06):  0-635. 
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    To solve the fracture problem of pin round punch when stamping small holes on stainless steel sheets, the structure optimization design of pin round punch was presented based on finite element analysis. First, four important factors were
    selected as the design variables, and the optimization mathematic model aiming to reduce the product of the stress concentration factor and the maximal von Misses stress
    was constructed. Then, the optimization process was carried out by ANSYS software. The results show that the B-type round punch is prior to A-type one in resisting fracture, and the resistant fracture of pin round punch is the best when the radius blend between guiding part and working part is R10mm. In addition, when the working part is free in stripper plate and its height is 2mm, the punch’s working life is the longest on stamping the stainless steel sheets with thickness is 1mm. There are little differences between the experimental results and the optimization ones.

    Research on Hydraulic System and Engine Power Matching for Heavy Transporter
    Li Kan;Zhao Jingyi
    2009, 20(06):  0-662. 
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    According to the power allocation characteristics of hydraulic system for heavy transporter, the principles of power matching between hydraulic system and engine for heavy transporter were analyzed from the engine and pump’s power matching, engine best operating point’s selection, and load and pump’s matching and so on. The plan and control rule of power matching was proposed in the full consideration of hydraulic system efficiency and the engine load. By means of TMZ100 heavy transporter’s experiment and practice, test results show that the power matching system satisfies the capability requirements of the heavy transporter and makes a great significance to improve performance and efficiency of the transporter; meanwhile it is useful for other huge driving construction machineries. 

    Vehicle State and Parameter Estimation Based on Dual Extended Adaptive Kalman Filter
    Lin Fen;Zhao Youqun
    2009, 20(06):  0-635. 
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    A critical component of vehicle dynamic control systems is the accurate and real time knowledge of vehicle key states when running on road. A new vehicle states estimator was proposed. First the nonlinear vehicle dynamics system was established in which contained inaccurate model parameters and unknown time varying noise. Then a dual extended adaptive Kalman filter (DEAKF) algorithm was proposed. In the algorithm two Kalman filters run in parallel, state estimation and parameter estimation update each other. In order to be robust to unknown time varying noise, the noise statistical estimator was inserted between state correction and parameter correction. The results of virtual experiment based on ADAMS and real vehicle experiment demonstrate that the DEAKF algorithm has higher state estimation accuracy than that of EKF and DEKF, also has good capability to revise model parameters. The conclusions can provide theoretic direction for design of estimator in vehicle stability control system.