Table of Content

10 April 2012, Volume 23 Issue 7

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Influences of Particle Size and Size Dispersion on Tribopairs Lubricated by Particulate Media

WANG Wei, LIU Xiao-Jun, LIU Kun

2012, 23(7):  757-761. 

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The experimental methods and continuum mechanics, which well be used in hydrodynamic lubrication, is no longer effective in studying the particulate media tribopairs. The discrete element method (DEM) was adopted to simulate the influence of particle size and size dispersion on the force, energy and friction characteristics in macro and micro scale. Benefit from the discontinuous mechanics, which was the theoretical basis of DEM, the discontinuity and inhomogeneity were exhibited well in mechanics and tribology. The randomicity and structural break of the movement and force were concluded. The media with bigger particles takes on a heavier load capacity and higher friction coefficient, and tends to form line-like strong force chain which leads to random behaviours and structural breaks in tribological characteristics. Under the circumstances of uniform dispersion and gauss dispersion, the distribution of load capacity and friction force are more continuous and smooth. Meahwhile, the motion of tribopairs is more stable, and the friction coefficient is lower.

Experimental Study on Abrasive Distribution of Electroplating Single-layer CBN Thin-grinding-wheel

LIANG Guo-Xing-1, LV Meng-1, LIU Ku-Chen-2, LI Wen-Bin-1, MA Lin-1

2012, 23(7):  762-766. 

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A new method for evaluating the density and uniformity on electroplating single layer CBN thin-grinding-wheel was mentioned herein. The maximum area-percentage-concentration of CBN abrasive was derived by means of establishing mathematical model under the condition of single layer distribution. Combining the experimental results, the relationships among the space-factor, planting-grit time and grinding-wheel density and among the space-factor, planting-grit time and uniformity were analyzed. Then the changing regular of grinding-wheel density and uniformity were obtained at the different space-factor and planting time. It is shown in the experimental results that the nonuniformity of the grit distribution mainly presents the specific surface difference of crowded grit and the amount difference of non-crowded grit in each observation area when the average current density value is 0.6A/dm2 and the duty factor is from 0.4 to 0.6. When the average cathode current density value is 0.2A/dm2, and the duty factor is from 0.1 to 0.3, the nonuniformity of the grit distribution mainly presents the amount difference of non-crowded grit in each observation area. In addition, extending plant-grind-time can increase the density of grinding wheel effectively when the average value electric current is a constant, but the abrasive distribution level of uniformity will be reduced obviously.

A New Vertical Direct Drive Volume Control System Used on Crane Arm and Its Energy-saving Characteristics

HU Zhi-Dong, WANG Li-Hai

2012, 23(7):  767-771. 

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A new vertical direct drive volume control electro-hydraulic servo system used on crane arm and its unique energy-saving superiority in driving vertical load system were introduced.The system used twin pump to control non-asymmetric cylinder,made non-symmetrical cylinder behave the motion characteristics of symmetric cylinder,overcome some shortcomings of non-symmetrical cylinder.Related simulation and experiments were done to verify this conclusion.

Design of De-icing Mechanism of De-icing Robot for High Voltage Power Transmission Line

WEI Shu-Ning, WANG Yao-Na, YI Feng, YANG Yi-Min

2012, 23(7):  771-776. 

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This paper first reviewed the development of de-icing robot for high voltage power transmission line inspection at home and abroad. Considering structural characteristics of different de-icing robots, three de-icing mechanisms,such as impact de-icing mechanism, milling de-icing mechanism, rolling-cutting mechanism were presented. Theoretical analysis results of key parametes such as cutting force, power, etc. were discussed. Corresponding de-icing experiments were designed to validate validity of the de-icing mechanisms. 

Heat Balance Analysis of Planetary Gear Train of an Earth Pressure Balance Shield Machine

TUN Xiao-Ling-1, 2, CHEN Li-Feng-1, 3, QIN Da-Tong-1, CHEN Hui-Chao-1, YU Zheng-Beng-4

2012, 23(7):  777-782. 

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Heat balance analysis of planetary gear train has great influence on the reliabity of EPBM and the operation of the planetary gear train. Without regard to the effects on the heat transfer properties of the internal temperature difference, the nodes substitute for all of the parts. The thermal resistances were employed to simulate the coupling among the parts, and the thermal network model (TNM) of the PGT was constructed by integrating the nodes. With the TNM, the thermal balance of the PGT of the
EPBM was studied and the thermal equilibrium states were discussed. Based on the simulation results, it is shown that the meshing number has important influence on the temperature rise.  The temperature rises of lubrication oil were tested and comparised them with the simulations.It is shown that the test results are good agreement with the numerical results. The results have elaborated that the thermal balance model can be avialable to estimate the temperature rise of PGT.

Simulation of Centroid Deviation for Warhead Based on Monte Carlo Method

GE Lin-Wei, OU Yang-Yong, LI Jia

2012, 23(7):  782-785. 

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The techniques of missile is developing to a long-distance and shoot straight trend, the reasons of the centroid deviation were discussed by considering the dimension errors of modules at the step of design. Take one missile as an example, a warhead module was calculated by using the Worst Case method and Monte Carlo method. The results show that the results obtained by Worst Case method always have a small probability, and the results obtained by Monte Carlo method are more reliable, and are of normaldistribution in its tolerance based on the errors of most mechanical accessory.

Study on Singularity and Workspace of a Novel Parallel Manipulator

LIU Wei, CHANG Sai-Qi

2012, 23(7):  786-790. 

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To solve the path planning problem of a six pyramid parallel manipulator, singularity and workspace of the manipulator were studied based on inverse kinematics equations with selecting criterion. A singular criterion equation was proposed by Jacobian matrix, and manipulability degree was introduced to analyze the singularity performance. Considering the limit of the joint and interference of linkages, a 3D workspace of the manipulator was presented by 3D boundary search method. Edge sampling experiments were done to show the simulation correctness and to provide theoretical basis for non singular path planning.

Damage Identification of a Beam-type Based on Grey Relation Modal Flexibility Curvature Difference(GMFCD)

WANG Tian-Hui-1, MA Li-Yuan-1, GU Ji-Wen-2, LI Shi-Long-1

2012, 23(7):  790-793. 

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The damages of a substructure were identificated by the proposed identification method. Numerical simulation examples indicate that the damage location and severity in structures, with single damage or multiple ones, can be detected efficiently by GMFCD through only a few of the lower order modal parameters. Compared to the aforementioned flexibility indicators, such as the change in flexibility, flexibility differential curvature method, the effectiveness and advantages of GMFCD are shown.

Modeling and Simulation on Heave Compensation System of Ship-mounted Crane

ZHANG Da-Bing-1, 2, WU Jian-Zhong-1, ZHENG Fu-Lai-1, LAI Xin-1

2012, 23(7):  794-797,809. 

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In order to reduce the impacts of wave on the hoisting in ship-mounted crane during offshore operation under rough weather conditions, a set of heave compensation systems was proposed for ship-mounted crane. A dynamic state space model of the system was built by selecting ship heave motion as input and different state variables as feedback, the payload displacement with passive and active-passive heave compensation modes were achieved respectively under suspensory state. At the end, dynamic performances of these two modes were analyzed according to the simulation results, then a cascade control was adopted as a control strategy in active-passive heave compensation mode.

Research on Development Mode of Modern Manufacturing Services and Its Development Strategy in China

LI Gao-1, 2, GU Xin-Jian-1, QI Guo-Ning-1, JI Yang-Jian-1, CHEN Ji-Xi-1

2012, 23(7):  798-809. 

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According to the analysis of modern manufacturing services business model at home and abroad,this paper gave the difference on manufacturing
services development level between China and developed countries,and pointed out the
deficiencies of the development model and strategy put forward by the scholars.Then,
 every stage's services of the whole life cycle of the product were given,and the classifications of the manufacturing service were sum up according to the service providing object and service phase respectively.Thirdly,this paper mainly summarized the
basic mode of modern manufacturing services.The business model of producer service
oriented manufacturing included regional cluster model,product service provider model,decentralized small and medium-sized enterprise dynamic alliance service mode and large enterprise service model,and the corresponding system structure and typical cases
were given respectively.The business model of product service oriented manufacturing included manufacturers extension service mode,user self-service mode,product service provider mode and integrated operation service mode,and the corresponding system structure and typical cases were given respectively.Finally,based on the current research,analysis and model investigation,the development strategies of China's manufacturing services were put forward,which will help to speed up the development of China's manufacturing services.

A Method in Matching Collaborative Product Development and Design Resource under Generalized Design Resource Mode

LI Guang-Dui-1, GUO Gang-1, DENG Xiao-Gang-2

2012, 23(7):  810-814,834. 

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According to collaborative product development in which the suppliers took part in product design process,all of design resources of the main plants and suppliers were integrated as design resource unit,aiming at a optimum distribution of the resources.The collaborative product development under generalized design resource mode was founded,and the model of scheduled task respect to design resource unit
was also established.Moreover,with the application of queuing theory,a new method was
proposed in matching design task and design resource.Finally,a method for solving the
problem caused by insufficiencies of resources was given.

Product Configuration Design Oriented to Satisfaction for Diversity and Green Requirements

BAO Hong, LIU Guang-Bi, ZHANG Lei, WANG Jin-Jing

2012, 23(7):  815-822. 

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On the basis of customer satisfaction model and configuration process model for green products,a design method of product configuration,which was oriented to satisfaction for diversity and green requirements,was proposed with a target on optimizing customer's satisfaction for green products.The model of green product structure was built by the application of modularization and generic bill-of-materials(GBOM).And  quality function deployment for environment(QFDE) was applied to the mapping among requirements of customer,characteristics of green products and module class.By analyzing green characteristics of each stage of cases of module class by adopting LCA theory and then on the basis of revising analysis results,an optimized configuration model was
established which was oriented to the best satisfaction for diversity and green requirements.Finally a case study of food milling machine was done to illustrate the feasibility and applicability of this method.

Research on Key Technologies of Services Planning for Collaborative Design Resources

MO Nai, DIAO Jie, YANG Yang

2012, 23(7):  822-828. 

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To achieve the target of combination and reusing for distributed resources during complex product collaborative design, a collaborative reusing structure based on services was built up. For realizing interoperation among heterogeneous collaborative services, a share ontology was constructed for design domain and a private ontology was established for tool resources. The invoking performance depends on ontology conversion. Collaborative service planning was divided into issue, search and planning phases. Service planning algorithm was proposed to get feasible combination schemes. At last, an ontology description of atom service was listed. Based on a serial of calculation services, an aero-engine compressor design instance was used to validate the service planning algorithm.

Modeling and Characteristics of Manufacturing Information System Based on Dynamic Controll Cell Structure

ZHANG Xiao-Hua-1, CHEN Wei-2

2012, 23(7):  829-834. 

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Fractal theory was introduced to the modeling course of manufacturing information system herein, a dynamic control cell structure was put forward as the generating cell, and the composition rules of  producing  fractal structure were found out. A fractal structural model was produced by fractal iteration. And the function characteristics, control charateristics and re-constrcuture were investigated. The model can express the operation of manufacturing information system clearly, reveal the inherent law of system, and describe system's dynamic operation characteristics, which reveal nonlinear coupling relationship among each function structures of the manufacturing information system. Finally, the model were compared with other models.

Early Fault Diagnosis of Rolling Element Bearings Based on Wavelet Transform and Independent Component Analysis

TUN Jiang, KONG Fan-Rang, HE Qing-Bei, LIU Yong-Bin, LI Feng

2012, 23(7):  835-840. 

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The key to fault diagnosis of rolling element bearings is how to find typical characteristic frequencies of rolling element bearings from low SNR mixed signals. A method was presented to combine continuous wavelet transform (CWT) with ICA for diagnosing early faults of rolling element bearings and a method to select wavelet scales with iso-interval frequency was proposed for the first time.Envelope spectrum was analyzed to diagnose the faults of rolling element bearings. Finally, the method has been verified by practical signal analyses of rolling element bearings.

Research on Vibration Signals of Internal Thread Formed by Cold Extrusion under Different Extrusion Speeds

LIANG Yu-Han, LI Xiang-Feng, ZUO Dui-Wen, ZHANG Min

2012, 23(7):  840-843. 

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The vibration signals of internal thread formed by cold extrusion under different extrusion speeds were researched.So the impacts of torque of internal thread formed by cold extrusion under different extrusion speeds can be explained by vibration signals. The results show that, as the extrusion speed increases, the frequencies of vibration signals move from low frequency to high frequency. The energy of vibration signals are mainly in the range of 625~1250Hz, and the more energy of this freguency range have, the more extrusion torque decrease.

Mathematical Model of Tolerance Based on Small Displacement Torsor

WANG Chi-Feng-1, CAO Yan-Long-2, XU Xu-Song-3, YANG Jiang-Xin-2

2012, 23(7):  844-846,880. 

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A new method based on SDT for tolerance modeling was studied herein. Based on the conception of the improved geometrical product specification, the deviation of feature was divided into intrinsic deviation and situation deviation. Then the SDT method was studied and the method for representation of 3D tolerance zone was given. Finally, mathematical tolerance model for different planes was established based on the proposed method.

#br# Dynamic Characteristic Analysis of Elastic Linkage Mechanisms with Interval Parameters

WEI Yong-Xiang-1, 2, CHEN Jian-Jun-1, JING Jun-Qing-2, MA Hong-Bei-1

2012, 23(7):  847-851. 

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Based on interval factor method, system dynamic characteristic analysis for interval  elastic linkage mechanisms was presented. Its stiffness matrix and mass matrix were discomposed into a sum of matrixes with same interval factors, respectively. By using interval factor method, the interval parameters can be all expressed as the products of two parts corresponding to the interval factors and deterministic value. Based on the Rayleigh's quotient formula, the computational expressions for the lower, upper bonds and mean value of system dynamic characteristic were developed using the interval operations. The effects of the uncertainty of the bar length and radius, mass density and elastic modulus on mechanism dynamic characteristics were studied through an example.

Markov Game Based 3D Path Planning for Palletizing Robot

LIU Jiu-Fu, CHEN Kuai, SU Jing-Qin, LIANG Juan-Juan, WANG Zhi-Qing

2012, 23(7):  851-855. 

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On account of complex application environments and large number of uncertain conditions for a palletizing robot, a path-planning method for multiple joints robot was presented by the algorithm based on Markov game. At first, according to the actual working environment, the range of the robot's motion was set and the conventional movement combination was selected as the basic set of the robot's behaviors. The possible reward of various situations would be obtained. Then the reward of each joint can be updated by multi-agent Q-learning algorithm and inverse the movement combination corresponding with the best reward. Selection of the movement combination parts can reduce the coordination among each joints and the complexity of the algorithm. The best motion trail will be shown, including the 3D motion trail when it's barrier-free and there was a spherical obstacle, and determination of the trail errors. At last, after experimental verification, the algorithm has been proved to control the compatible movements of each joint effectively and keep the errors within the allowed ranges. The experiments meet the requirements well.

Structure Analysis and Optimization of Product Design Process

RONG Zhi-Jun, CHEN Kui-Sheng, YING Bao-Qing, LIU Yue

2012, 23(7):  856-859. 

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The hierarchical structure of design process was first analyzed herein. The design components were hierarchicalized with the design modeling and a planning and control model of design process was established. The definitions of node, hierarchicalization and hierarchical structure in design process were presented. A hydraulic system design was used as an example to illustrate the structure model,and an optimization algorithm was proposed based on the structure model.

Multi-objective Topological Optimum Design of Compliant Mechanisms Using Hybrid Cellular Automata Method

NI Yun-1, TIE Jin-Jing-2, SHU Da-Chang-3

2012, 23(7):  860-864. 

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A multi-objective topology optimization method for compliant mechanisms was proposed using hybrid cellular automata method. The multi-objective function was developed by the minimum strain energy and maximum mutual strain energy to design the mechanism which met both stiffness and flexibility requirements, respectively. The objective function was normalized to eliminate magnitude difference of the objectives. The structure volume was used as the constraints. The hybrid cellular automata method was adopted as solving strategy for the multi-objective topology optimization problem. The local changes in the design variables were determined by local rules based on the proportional control law. A numerical example was presented to show the feasibility of the approach. The iteration number of optimization is relatively fewer, and the final topologies have less one node hinges.

Research on Three-dimensional Contact Model and Stress Distribution between Wires of Steel Strand

MA Jun-1, GE Shi-Rong-2, ZHANG De-Kun-2

2012, 23(7):  864-868. 

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A three-dimensional contact model of 1×19IWS steel strand was established. Contact point was searched by Splitting-pinball algorithm, Augmented-Lagrangian algorithm was applied for analysis of contact loads.  The exerted tensile loads to the model was analyzed using FEM. After analysis of calculation results, the laws of steel wire stress distribution in axis direction and in its cross section were found. Friction coefficients were set as 0.10, 0.11 and 0.12 respectively to obtain the influence law of friction coefficient on steel wire stresses.   Research result show that friction coefficient has significant influence on the shear stress of steel wire. The calculation results of steel strand with five different lay pitch multiples were analyzed and the influence law of lay pitch multiple on the stresses of steel wire in steel strand was obtained. The Von Mises stress of steel wire increases following with lay pitch multiples, but the increment value is not very prominent. The shear stress of steel wire decreases following with the increase of lay pitch multiple, the changing amplitude is large when lay pitch multiple is small. Finally, a steel strand tensile deformation test was carried out and the consistency of test results with the calculation results shows that the selected model is reasonable.

Development of Control Strategy for a Series-Parallel Hybrid Electric City Bus Based on Roadway Type Recognition

LIN Xin-You, SUN Dong-Shu

2012, 23(7):  869-874. 

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To improve fuel economy of a novel series-parallel hybrid electric bus(SPHEB) further,and four types of roadway were selected to present the characteristics of city driving cycle,a learning vector quantization neural network was adopted to learn and identify the driving cycle,and integrated with the power balancing strategy which was derived from the results of global optimization based on dynamic programming.
So a driving cycle adaption control strategy was proposed.To validate the proposed
strategy to be effective and reasonable,a forward model was built based on MATLAB Simulink,and the results were compared to that of normal strategy.The simulation results demonstrate that the proposed strategy can be more efficient and the improvement of fuel economy is up to 7%.

#br# Study on Ride Comfort of a Rhombic Bus Based on MATLAB

ZHANG Xi, MO Xu-Hui, ZHONG Zhi-Hua

2012, 23(7):  875-880. 

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An eleven DOF model of a rhombic bus was built, and the effects of each design factors on ride comfort was analyzed. With weighted vertical root mean square values of each passenger's acceleration as optimization objective, and with dynamic displacement of each suspension and relative dynamic load of each tire as constraint conditions on random road, the parameters of suspension were optimized by NSGA-Ⅱ. The ride comfort of the rhombic bus is improved after optimization, and the change rule of the rhombic bus's ride comfort on pulse road was analyzed based on the optimized parameters of suspension.