Table of Content

10 September 2009, Volume 20 Issue 17

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Analysis of Performance Influenced by the Joints’ Distribution of a Novel Parallel Manipulator

Shi Yan;Lu Yi

2009, 20(17):  0-2021. 

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The influence of joints’ distribution on a novel parallel manipulator performance was studied. Firstly, a cube work region was defined, and the analytic relationship between workspace point Cartesian coordinates and some manipulator parameters which were important to application was derived. Secondly, when the revolute joint pose varied, the output velocity and the force varying laws within the prescribed work region were discussed. Meanwhile, limb-stroke varying law was solved through GA (genetic algorithm) tool of Matlab. Finally, joint distribution choice criteria meeting different requirements were listed according to study results.

Requirement Decomposition and Weights Allocation of 
Complex Mechanism Scheme Design Based on Basic Element

Jin Xiangyang,;Wang Tichun;Zhong Shisheng;Bu Liangfeng

2009, 20(17):  0-2112. 

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The customer requirements of complex mechanism scheme design were described formally by basic element. According to basic element implication, a requirement model of customer requirements based on the basic elements was presented. For the incomplete and the restricted information of requirement characteristics, a computing method of multi-attribute weights allocation based on grey relational analysis was proposed. Firstly, the importance rating of the requirement characteristics was got, then by regarding each requirement characteristic as judgement code, the relational coefficients and a corresponding relational matrix was obtained.Based on these, the weights of each design attribute were achieved. Finally, an example of large-scale hydraulic turbine scheme design was provided to validate and prove its efficiency and feasibility.

Tool-wear Monitoring Based on LPCC of Cutting Sound

Ai Changsheng;He Guangwei;Dong Quancheng;Ze Xiangbo

2009, 20(17):  0-2021. 

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A new tool-wear monitoring method was presented, which was based on LPCC of cutting sound. Firstly, audible cutting sound was characterized by LPCC, then the relationship among the components of LPCC and tool wear was analyzed, tool-wear state was reflected by the weighted sum of relative LPCC components, and finally proved by experiments. The research results indicate that the weighted sum of relative LPCC components abstracted from audible cutting sound can reflect effectively tool-wear states. 

Kinematics Characteristics of Vibration Drilling and Its Influence on Processing Quality

Ma Lijie,;Wang Xibin;Liu Guanjun;Fu Sufang

2009, 20(17):  0-2112. 

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Based on the basic principle of vibration drilling, its kinematics characteristics was analyzed and the cutting conditions of twist drill were studied. Then, by the aid of the self-made piezoelectric vibration table, experiments of vibration drilling were done on duralumin (2A12) and stainless steel (0Cr18Ni9), and the aperture size, surface topography and surface roughness were tested. The results show that, contract with common drilling, vibration drilling has some kinematics characteristics, such as variable-thickness cutting, variable-speed cutting and variable-angle cutting, which can improve chip-breaking condition, working condition of chisel edge and operating angle of main cutting edge. So vibration drilling has higher dimensional accuracy and better surface quality than that of common drilling.

Principle and Method of Relativity Rest Test for Measurement of Spindle Rotation Error

Tang Jinyuan;Chen Haifeng

2009, 20(17):  0-2021. 

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In the process of the spindle error measurement,it gets low level of accuracy with present methods,since there is relative motion between the testing device and the object under test. A new measurement method for radial rotation error was
presented herein.Through the introduction to multi-body dynamics coordinate transformation theory,in the process of measurement testing devices and the objects under test
remained relatively static,then the changing conditions of transformation device were
derived.Combining the changing conditions with laser triangulation measurement,the new method was obtained.

Effects of Meshing Phase on Natural Characteristics of Planetary Gears

Duan Fuhai

2009, 20(17):  0-2112. 

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The method for calculating the meshing phase and a torsional dynamics model of planetary gear were developed to study the effects of meshing phase on natural characteristics of planetary gears. The effects of meshing phase on natural frequency and vibration mode of planetary gears were analyzed. The results show that the meshing phase influences the natural characteristics of planetary gears significantly, and there are various compound modes for mesh stiffness in planetary gears because of these meshing phase, which leads to closed frequencies of occurrences in the system. There are difference vibration modes for planets because of closed frequencies of occurrences, which makes non-uniform load on each planet resulting in the reliability of planetary gears reduce.

Uncertainty Analysis on Swing-arm Profilometer for Optical Aspherics

Jia Lide,；Wang Jiawu；Zheng Ziwen；Li Shengyi

2009, 20(17):  0-2021. 

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With the experimental set-up of swing-arm profilometry,all kinds of errors which will affect the accuracy were analyzed.The mathematical models of the posture errors,the axial and radial run outs,the radius of the probe,and the flexure of the measurement arm were built.Several environmental factors,such as temperature and
vibration,were analyzed and tested practically.Finally,a concave paraboloid (R=1400mm,D=200mm) was tested.The experiments indicate that the uncertainty of the set-up
is better than 0.5μm.

Numerical Calculation and Experiments of Micro Nozzle’s Impinging Force

Tong Junjie, ;Xu Jinliang;Cen Jiwen

2009, 20(17):  0-2112. 

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The software FLUENT6.3 was applied to simulate the micro nozzle by using the RNG k-ε model with the enhanced wall treatment. The simulation was employed to study the effects of the distance from thruster exit to the probe on velocity contours nearby the probe, pressure contours in front of the probe and impinging force which the probe was impacted. Also experiments were carried out to testify the simulation thrust force results. The simulation results and experimental results indicate that when the thruster inlet pressure keeps consistent, the impinge force which the probe is impacted increases firstly and then decreases as the distance from the thruster exit to the probe increases, and the impinge force increases linear appropriately with thruster inlet pressure.

Temperature Compensation for MEMS Gyroscope Based on Hierarchical Genetic Algorithm and RBF Neural Network

Chen Diansheng;Shao Zhihao;Lei Xusheng;Wang Tianmiao

2009, 20(17):  0-2021. 

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The bias and scale factor of MEMS gyroscope are often influenced by temperature. To get the high precision attitude information, this paper proposed a temperature compensation scheme based on RBFNN. A new hierarchical genetic algorithm was also used to optimize the network construction and parameters. The effectiveness of the proposed scheme was shown by a series of tests. The error of the angular speed is controlled within ±0.5°/s under real conditions.

Study on Buckling of Composite Box Structure

Lu Binghe;Wan Xiaopeng;Zhao Meiying

2009, 20(17):  0-2112. 

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Finite element method was adopted to research the buckling problem of the composite box structure, which was composed by lots of different thin-panel members and was simplified. Linear and nonlinear methods were used for buckling calculation of the composite box structure, under the torsion and bending load separately. Compared with experimental data, both of the finite element methods have good calculating results in torsion condition. Nonlinear method still gets accurate outcome in bending condition, but linear method doesn’t. Hence, Using nonlinear method to calculate buckling problem of the complex model, such as composite box structure, can receive more precision than linear method.

Application of Improved ICA & HHT in Fault Diagnosis of Rotors

Chen Jianguo;Wang Fengtao;Zhu Hong;Zhang Zhixin;Li Hongkun

2009, 20(17):  0-2021. 

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In many cases, ICA is used to separate independent components from time-frequency images of different faults obtained by Hilbert Huang transform (HHT). However, because of the potential correlated components contained in most images, an improved ICA method based on sub-band mutual information, which can eliminate the correlated components of the original image, was proposed to obtain a group of standard fault time-frequency images. Second, projection coefficients, which were acquired by calculated time-frequency image projections of different fault signals on the standard fault images, were used to realize automatic classification of different faults. At last, three kinds of rotor faults (early rub, loose, misalignment) were investigated to testify the efficiency and feasibility of this improved method.

Architecture of Collaborative Simulation Environment for 
Complex Products Based on Petri Net and Multi-agent

Wang Haiwei;Liu Geng;Yang Xiaohui;He Zhaoxia

2009, 20(17):  0-2112. 

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In the process of complex product development, the simulation analysis for product performance was faced with the needs of collaborative simulation. Analyzing the basic PN models of the process management system in collaborative simulation environment (CSE), the CSE discrete event dynamic system(DEDS) model was presented based on Petri net. As the implementation unit of simulation tasks in the CSE PN process, simulation component model was built based on multi-agent technology. Through integrating the two models, the CSE system architecture model and its running mode were discussed, to achieve modeling and control of simulation process, and collaborative running of various simulation tasks. Finally, the proposed modeling approach was applied in the suspension system on the simulation platform developed and its feasibility was demonstrated.

Economic Analysis on the Extensive Quality Loss Model

Zhang Genbao;Liu Shuaishuai;Zhang Peng;Ren Xianxin

2009, 20(17):  0-2021. 

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In order to study quality failure in the aspect of economy,this paper improved quality failure function by using the theory of paragraph function,associating with the real situation of quality failure and based on the analysis of the limit of Taguchi quality failure function,and then the paragraph model of quality failure was obtained.We will control the quality failure function curve according to the shift of the quality characteristics curve and the change of the curve’s shape, the control method will be discussed. Also,the formula of calculating and improving the failure will be given for minimizing quality failure.The example in the end of the paper proves the value of the quality failure paragraph model.

Simulation of Automated Container Terminal Loading and Unloading Technology

Zhu Minghua,;Fan Xiumin,;Cheng Huanchong,; He Qichang,

2009, 20(17):  0-2112. 

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A new container terminal loading and unloading technology,
composed of double-40-foot quay cranes,a low bridge allocation system and rail-mounted gantry cranes(RMG),was analyzed in detail.The events of key equipment were defined.A loading and unloading process simulation system was developed based on event-driven and virtual reality technology.The analyses were focused on the characteristics of quay cranes and the low bridge allocation system under the new technology,and the equipment operating efficiency was calculated through the simulation.The simulation results show that comparing with traditional container terminal,the automated container terminal with the new technology has higher operation efficiency.

Affection of Assembly Temperature on Thermal Fatigue Life

Tian Fang;Yan Ming;Tao Ke;Jiang Zhanli

2009, 20(17):  0-2021. 

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Mechanics mechanism of thermal fatigue and the affection of assembly temperature on thermal fatigue life were studied by using finite element method in consideration of the multilinear kinematic hardening of a material. It is discovered that an appropriate assembly temperature of specimen(material is ZL702A) can make its thermal stress cycle in elastic range, which can prolong the thermal fatigue life. The appropriate assembly temperature is related to mechanics properties of material and operating temperature, so reiterative computations are necessary to find an appropriate assembly temperature by the method that makes the maximal tensile stress smallest under conditions that the maximal compressive stress is less than the compressive yield point of material.

Study on Description of 4D Product Information Model Based on Hypergraph

Wu Xiang;Li Gangyan

2009, 20(17):  0-2112. 

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Aiming at the complexity and dynamic property in product design process, product 4D information model was established based on interconnection hypergraph. The method of describing the relationships among different stages in product design process by making use of hypergraph was advanced, which can be applied to record product design process evolution history, and realize the dynamic information traceability, providing a new approach and research method to product design and the process management of it.

Experimental Research on Boundary Slip of Confined Liquids at 
Micro/nano Scale and Effect of Shear Rate

Wang Xin,;Zhang Xiangjun;Meng Yonggang;Wen Shizhu

2009, 20(17):  0-2021. 

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In order to research the flow property of liquids between solid and liquid at micro/nano scale, a commercial atomic force microscope was modified by attaching a glass ball to the end of cantilever at micro/nano scale, which was used to investigate influence of approach velocity on boundary slip. Solid surface specimen was Si（100）verse deionized water. Results indicate that, when the distance between the glass ball and solid surface is below critical value, boundary slip will not affect the hydrodynamic force. The critical distance will decrease with the reducing of the velocity and it means boundary slip is dependent with velocity. The relationship between shear rate and boundary slip was discussed. It shows that boundary slip will occur only when the shear rate reaches some value.

Application Research on Entire Vehicle Virtual Assembly Technology Based on Grid Environment

Dai Yi;Qu Xiaobin 

2009, 20(17):  0-2112. 

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An entire vehicle virtual assembly platform based on grid environment was constructed herein,where the domestic self-developed grid-middleware grid operation system(GOS) was used, the interconnection and resource sharing were achieved successfully among several testing master nodes. Based on this work, the platform was verified in the real industrial environment of the car manufacturer and its suppliers. The results indicate that by the use of the presented virtual assembly platform, the limitation of region and single computer ability will be broken to a great extent, so the collaborative assembly can be achieved effectively and steadily. 

Research on Differential Geometry of Stranded Wire Helical Springs

Wang Shilong;Xiao Hong;Zhou Jie;Lei Song

2009, 20(17):  0-2021. 

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The geometric equations were put forward on a single-wire in the stranded wire helical springs based on the winding relationship between the center curve of the wire and of the springs, the differential equations of curvature and torsion etc. were derived as well. Taking the compression springs and extension springs as instances to analyze the changes of curvature and torsion of the single-wire both in the same and different values of twisting angle of the strand by software MATLAB. The results show that the difference of curvature effects on the stress-strain ability of the stranded wire helical springs, and the value of the twisting angle of the stranded effects on the stiffness of the stranded wire springs. The results can give more thought and basis on elastic-plastic and performance of the stranded wire helical springs.

Research on Single-chain Spiral Interventional Micro Robot

Chen Bai;Jiang Surong;Chen Sun; Wu Hongtao

2009, 20(17):  0-2112. 

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Based on analysis of the driving principle of dual-chain spiral-type interventional micro robot, a single-chain spiral micro robot was presented. The numerical model of the single-chain interventional micro robot was made. A dual-chain type micro robot and a single-chain type interventional micro robot whose diameters were 5mm respectively were produced. The moving speeds of the two interventional robots were studied comparatively in isolated intestinal canals. The results show that the single-chain interventional micro robot has similar properties to that of the dual-chain structure micro robot. The operating experiments of single-chain micro robot under the simulated aorta environment show that the spiral-type micro robot can move stably in forward flow and counter flow.

Real Time Prediction of BHF Control Law in Intelligent Deep Drawing for Rectangular Box

Ma Rui;Zhao Jun;Qu Xiaoyang

2009, 20(17):  0-2021. 

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The real time prediction of BHF control law in intelligent deep drawing is a key technology.A non-axisymmetrical workpiece such as rectangular box was studied and as a result the topological structure of BHF prediction model in real time was showed by introducing ANN. In this way preparion of sample, accuracy of model convergence and accuracy of model generalization were studied. It is indicated when input samples are normalized, training method is regularized and the right numbers of samples and hidden nodes are set, the accuracy of generalized results can be within 10%. This measure will meet to the engineering applications.

Modelling and Analysis of a Pneumatic Force Control System with an Asymmetric Servovalve

Yin Yaobao;Araki Kenji

2009, 20(17):  0-2115. 

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The mathematical model of a pneumatic force control system with an asymmetric servovalve and a single-acting cylinder were described. From the experimental results of an asymmetric servovalve, the typical three coefficients of flow gain, flow-pressure coefficient and pressure gain are obtained. The dynamic models were derived and simplified to be as a transfer function of the third order. The relations among mechanical parameters and frequency bandwidth, steady-state error of the system were also discussed. The calculation results are in good agreement with the experimental ones.

A Two-fluid Large-eddy Simulation of Axi-symmetric Sudden Expansion
Dilute Gas-particle Flows

Liu Yang,;Li Guohui

2009, 20(17):  0-2021. 

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A two-fluid large-eddy simulation (TWF-LES), based on the Smagorinsky SGS stress model with particle kinetic theory was used to study axi-symmetric sudden expansion dilute gas-particle flows. The instantaneous results give the evolution of anisotropic two-phase turbulence structures and particle dispersion processes.The TWF-LES statistical results of particle averaged velocity and RMS particle fluctuation velocity are in good quantitative agreement with the experimental ones. But, in the shear flow region，the value of particle phase fluctuation velocity and in the axial direction of particle fluctuation velocity correlation of particle-gas phase predicted by TWF-LES are difference with those experiments a little. It implies that the TWF-LES modeling remains to be further validated and improved.

Study on Mechanism of Electrode Wear in Micro-EDM

Wang Yuangang;Zhao Fuling;Liu Yu;Wang Jin

2009, 20(17):  0-2115. 

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Wear of electrodes in Micro EDM affects shape and dimension precision of workpieces. Situations and impacts of electrode wear were analyzed by experiments, and the mechanism of electrode wear was discussed based on finite element analysis and electromagnetic theory. From the results it is shown that electric field concentration is the basic reason of edge wear, shape keeps steady when wear develops to certain stage and that the current density is not unvarying in a cross-section of the electrode but increases powerfully towards the periphery in the electrode at high frequency caused by discharge, which is the main sources of secondary discharge in micro- EDM. 

Warm Compaction of Tungsten-Copper Powder

Cheng Jigui;Cai Yanbo;Song Peng;Wan Lei

2009, 20(17):  0-2131. 

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W-20wt%Cu powder was warm compacted with a new binder. Effects of compacting temperature, pressure and particle size of the starting powder on green density of the warm pressed W-Cu compacts were investigated,and compared with those of cold compaction. The results show that warm compaction effectively increases green density of the W-Cu compacts. A maximum green density of 10.68g/cm3 is obtained for W-Cu compacts pressed at 170℃ and 400MPa, which is 0.55g/cm3 higher than that of cold compaction. The particle size of the starting Cu powder also has an obvious influence on the green density of W-Cu compacts. The warm pressed W-Cu compacts show higher sintered density than the cold pressed compacts. Furthermore, sintered W-Cu materials from the warm pressed W-Cu compacts have improved microstructure and good physical and mechanical properties. 

Study on Reduced Methods in Solving Complex and Multi-parameterized 
Large Scale Problem in Automotive Body Design

Lei Fei;Han Xu;Huang Yonghui

2009, 20(17):  0-2131. 

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A hybrid algorithm was suggested to reduce the complex and multi-parameterized large scale problem to a small one in automotive body design based on reduced-basis methods and finite element methods. Approximate solution space was created by computing responses of large scale problem at some selected points. Design variables were separated from matrices by decomposing the stiffness matrix in finite element procedures. The separated matrices were projected to the approximate solution space to create reduced system. The solution of large scale problem is obtained by solving the reduced system, and it is much more efficient with new variables. By using hybrid algorithm, the application of reduced methods in solving large scale problem is possible.

Development of a Test Bench for Automobile Seating Comfort Evaluation

Jin Zhe,;Cheng Bo;Jin Xiaoping;Shen Bin;Javier Alcazar

2009, 20(17):  0-2021. 

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A 2007 SGM Buick Park Avenue was modified to satisfy adjustability requirements for automobile seating comfort studies. It was designed with multi-degrees of freedom to control each adjustable feature. Adjustable pedal mechanism was proposed and implemented. Algorithm to obtain seat height from absolute encoder revolutions was developed. Test data is presented to validate that the modified car test bench is a reliable platform for seating comfort studies with high precision, stable performance and abundant adjustable parameters.

Computational Simulation and Test Study of an Extendable and 
Retractable Automobile Crash Energy Absorbing Device

Cao Libo;Ding Haijian;Li Ke;Cui Chongzhen

2009, 20(17):  0-2137. 

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The operation principle of an extendable and retractable crash energy absorbing device was introduced. A sample of the device was designed and manufactured according to a production SUV’s frontal structure. It had been installed in the SUV, and its control system had also been developed. Finite element model was developed to study the frontal impact performance of the device. Meanwhile, low and high velocity sled impact tests were used to study the device’s performance in its extended status and retracted status respectively. The simulation and test results show that the device can effectively increase the SUV’s crush space and improve the energy-absorption performance during the impact when the device is extended, and better protection effect can be achieved for the occupant. When the device is retracted, no bad influence will bring to the SUV.