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Table of Content

    10 January 2012, Volume 23 Issue 1
    Strategic Significance and Technical Route of “NC Generation” Mechanical Product Innovation Project
    ZHOU Ji-1, 2, SHAO Xin-Yu-2, ZHOU Yan-Gong-2
    2012, 23(1):  1-6. 
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    To accelerate the transformation of economic growth pattern, efforts should be centered on adjustment and optimization of industrial structure with the key being upgrading of products. Numerical control is an effective approach to the innovation of mechanical products. The technique route is to replace power unit and gear of traditional machinery with servo motor driving system and to control mechanical movement and working process with CNC system, thus fundamentally improving product function and performance, and enhancing product market competitiveness. The “NC Generation” mechanical product innovation project, involving NC technology applications and innovation of mechanical products, is one that is driven by huge demands from development of machinery industry and boosted by mature NC technology. The execution of this project should fully harness the nation's superiority in system by carrying organized innovation. Following an integrated, collaborate innovation technology route with “enterprise as the dominant force, market as the guidance, and featured by combination of governments, producers, schools, research institutes and users”, the project should be planned comprehensively, implemented step by step and with focuses, and advanced in an all-around way. The objective is to popularize and apply NC technology, to realize the overall innovation and upgrading of China's mechanical products in ten years and ultimately to contribute to China shifting from a giant manufacturing force to a powerful nation.
    Research on Quality Monitoring and Diagnosis Technology for Thrust Washer Processes
    JIAN Xiao-Yao-1, JIAN Jia-Wei-2, HONG Wei-1, SUN Chang-Jing-1, XU Xin-Qing-1
    2012, 23(1):  7-11. 
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    On the basis of analysis of the limitation of existing research on SPC control of the thrust washer of transport vehicle, an expert system theory was introduced to quality control of the thrust washer. Analyzing at the requests of the testing and quality control of the thrust washers in transport vehicle, the structure, knowledge acquisition and inference engine of the SPC expert system in total system design were discussed, and the whole framework of quality monitoring and diagnosis were built. An automatic detection device of the thrust washer was developed,and such functions as automatical data acquisition, storage and analysis, drawing of control chart, expert diagnosis analysis were realized. The development and applications of this system demonstrate its realistic effect of quality diagnosis and control in thrust washer processes.
    Multi-objective Optimization of Multi-stage Planetary Gear Train Used in Shield Machine Cutter Driver
    QIN Da-Tong, DIAO Yong
    2012, 23(1):  12-17. 
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    Multi-stage planetary gear train used in shield machine cutter driver requires high reliability, low vibration and high power density. Based on the reliability model and the dynamics model, a multi-objective optimization model of multi-stage planetary gear train used in shield machine cutter driver was developed to improve the reliability, minimize the vibration and the overall volume of the system. The optimization of a practical example using mixed discrete combined programming was carried out. The results demonstrate that the optimization model and method can effectively increase the reliability, reduce the vibration level and overall volume of the multi-stage planetary gear trains used in shield machine cutter driver.
    Dynamics Analysis on a 3-DOF Rotational Platform with Serial-Parallel Structure
    GAO Zheng-1, XIAO Jin-Zhuang-1, WANG Hong-Rui-1, JIN Zhen-Lin-2
    2012, 23(1):  18-21,38. 
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    Dynamics of a 3-DOF (degree of freedom) rotational platform was analyzed. This rotational platform, which consists of a 2-DOF spherical parallel mechanism and a rotational degree connecting in series to the platform of the 2-DOF mechanism, has only 3 rotation freedoms. System's input-and-output velocity functions were established according to rotational platform's geometry and motion characteristics, and then the velocity Jacobian metrics and energy functions were obtained. System's dynamics model was established by Lagrange method and virtual work principle, and then the drive torque was solved when given the external load, velocities and accelerations. The
    examples of dynamics simulation were given. The drive torques' changing curves of the 2-DOF spherical mechanism was discussed under the situation of uniform speed and acceleration. Finally, according to the dynamics functions, a third degree's kinematics equation was obtained respecting to its torque and output angle. 
    Investigation of Cavitation Phenomena in Valve Port of a High Frequency Electro-hydraulic Digital Rotary Valve
    BAI Ji-Beng-1, 2, RUAN Jian-1
    2012, 23(1):  22-28. 
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    With the FLUENT software, by studying the flow field in the chambers of 2D digital valve, this paper explored the cavitation variation rule in extreme situations with an attempt to find the effects on valve port flow by bubble precipitating, developing and collapsing during the periodical and high-speed on-offs. The results show that cavitation causes flow rate congestion, and that the pressure fluctuation caused by the bubble collapse brings significant nonlinear impact on the valve controlled cylinder, which reduces accuracy of the valve ports' output waveform and output stability of the valve controlled cylinder vibrator.
    SKO Structural Topology Optimization Method Based on a Continuous Step-up Reference Stress Criterion
    HOU Jian-Yun, DING Xiao-Gong
    2012, 23(1):  28-33. 
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    In order to avoid the local minimum during the optimization iterative process based on the SKO technique, a continuous step-up reference stress criterion was proposed. The reference stress was defined that the average stress multiplied a weighted parameter which can be changed by the current iterative state automatically. When the optimal iteration achieved a local minimum, the weighted parameter was increased automatically by a certain specified value, hence the reference stress was increased and the optimal iteration can be continued. The proposed method included two iterative cycles, in which the inner one was the local optimal iteration, while the outer one was the global optimal iteration. When the volume change between two iterations is smaller than a specified tolerance, the optimal structure is obtained. The design parameters of the proposed method were studied, and the validity of the proposed method was given by several typical design examples.

    Bearing Fault Diagnosis Based on Multi-scale Hermitian Wavelet Envelope Spectrum
    AI Shu-Feng
    2012, 23(1):  34-38. 
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    A new method of bearing fault detection and diagnosis was proposed based on multi scale Hermitian wavelet envelope spectrum. The multi scale Hermitian wavelet envelope spectrum technique combined the advantages of Hermitian wavelet transform, envelope spectrum and three dimensions color map into one integrated technique. The bearing fault vibration signals were decomposed using Hermitian continuous wavelet transform firstly. Then the real and imaginary parts were obtained. In the end, the multi scale Hermitian wavelet envelope spectrum was obtained and the characteristics of the bearing faults can be recognized according to the multi scale Hermitian wavelet envelope spectrum. The proposed method has been proved by vibration signals obtained from rolling bearing with inner or outer race faults. 
    Ultrasonic Elliptical Vibration Precision Machining for Aircraft Intersection Holes
    ZHANG De-Yuan, ZHANG Cheng-Mao
    2012, 23(1):  39-41. 
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    The machining processes of aircraft intersection holes for more than 30mm existed many problems by ordinary cutting method, such as shortage of power,
    low precision of the diameter and poor surface quality. Ultrasonic elliptical vibration boring was used herein and the components of ultrasonic elliptical vibration boring were explained.The aircraft intersection holes more than 30mm were bored. Subsequently, the practical machining effects of ultrasonic elliptical vibration cutting were clarified. Finally, the characteristics of ultrasonic elliptical vibration cutting were summarized.
    Numerical Simulation on Dynamic Characteristics of a Extra-high Pressure Pneumatic Blowing Valve
    YANG Gang, SUN You-Bin, LI Bao-Ren
    2012, 23(1):  41-45. 
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    An extra-high pressure pneumatic blowing valve was analyzed and a mathematical model for the valve was established based on real gas equation of state. The effects of structural parameters and boundary conditions on dynamic characteristics of the valve was studied by simulation. The results of the paper is very helpful for the optimization design of the valve.
    Design and Implementation in Integration of Form System and Workflow Engine
    WU Shao-Long-1, 2, FANG Xiao-Fen-1, 2, DONG Jian-Feng-1, 3
    2012, 23(1):  46-50. 
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    To solve product design workflow form design problem, a form system integrated with workflow engine was designed and implemented. In product design process, for form system needs to integrate with workflow engine to do task transfer functions, and there are much needs such as the nodes of workflow need to control the display permissions of the form elements, the parameter mappings between the workflow variables and form elements existing in the integration, this paper proposed a new design and implementation solution, including configuring the control permissions dynamically and parameter mapping. This solution has successfully integrated system workflow engine and form system in HTC project management,the results show that this solution can solve the issues mentioned before.
    Forming Quality Forecast for Internal Threads Formed by Cold Extrusion Based on Principal Component Analysis and Neural Networks
    ZHANG Min, LI Xiang-Feng, ZUO Dui-Wen, JIU Hong
    2012, 23(1):  51-54. 
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    Forming quality grade of internal threads formed by cold extrusion was rated synthetically by BP neural network based on pitch diameter, thread pitch, half of thread angle and threads height ratio. For eliminating linear relevance in inter-influencing factors while the data pre-processing, major factors that affected the forming quality of internal threads formed by cold extrusion were extracted by principal component analysis. The experimental results show that the neural networks input by the processed data by this method become simple, with improved convergence rate and forecast accuracy. This method realizes the forecast for quality grade of internal threads formed by cold extrusion precisely. Also it provides a new solution for detection of internal thread quality.
    Linear Servo System Control Based on Improved Elman Neural Network with Sparse Memory
    ZUO Jian-Min-1, 2, BO Chao-1, 3, HONG Mu-Lan-4
    2012, 23(1):  55-58. 
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    In order to improve the dynamic performance and disturbance resistance abilities of CNC machine tool direct-drive linear servo system with complexities of dynamics and nonlinear, taking advantages of historical control information of repeated motion, an improved Elman neural network with spares memory was proposed and rapid associate theory based on table-look up was introduced to enhance learning speed and generalization capability of neural network. The information of neural network was classified, stored and selected to use. The mathematical model of improved Elman neural network and the weight adjustment algorithm were derived in detail and applied to a linear feed servo system.The results show that the controller based on improved Elman neural network with spares memory exhibits satisfactory performance in tracking precision and disturbance resistance.
    Optimization of Process Selection and Sequencing Based on Genetic Algorithm
    ZHENG Yong-Jian, WANG Yang
    2012, 23(1):  59-65. 
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    An optimization model was built for the process sequencing of housing parts by taking the total machining time as the optimization objective. In this model, the machining center was assumed to has multiple clamping and each part feature has multiple processing methods, and the feature constraint matrix and the processing priority factor were introduced to ensure the reasonable constraints in the processes. The methods of generating the initial population, the selection, crossover and mutation of the chromosome were designed, and then the processing program was selected and sorted by using the genetic algorithm. Finally, sample parts were selected and tested,and the experiments show that this method can improve the process sequencing optimization ability effectively.
    Research and Application of Intelligent Grinding Cloud Platform Based on Cloud Computing
    DENG Chao-Hui-1, 2, LIU Wei-2, TUN Ti-Xin-3, CENG Yu-4, 5, XIE Zhi-Meng-2
    2012, 23(1):  65-68,84. 
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    Industry and manufacture need the support from information technology, cloud computing is a direction of new generation internet technology, which creates a new service platform to use the resources of industry and manufacture. According to the characteristics of industrial cloud and cloud manufacturing,an intelligent grinding cloud platform was put forward and set up by applying cloud computing into grinding. The principles, structure and key technologies of intelligent grinding cloud platform are introduced. Furthermore some software products about grinding cloud were listed for the applications of cloud computing technologies. At last, the future of intelligent grinding cloud platform was made.
    Research and Practice of Industrial Cloud Computing Platform
    CENG Yu-1, 2, WANG Ji-3, TUN Ti-Xin-4, DENG Chao-Hui-5
    2012, 23(1):  69-74. 
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    Cloud computing platform and cloud computing services have become the mainstream service carrier and service model of post-supercomputing era. The changes in its technologies and innovation in its service models will profoundly affect the industrial technological innovation and the development of industrial competition, and will strong promote the regional science and technology innovation and speed the pace of regional economic restructuring. This paper analyzed the necessity of building cloud computing platform to promote the innovation and development of the manufacturing sector, analyzed the architecture and key technologies of industrial cloud platform, and introduced the platform development, implementation, and typical application examples. The platform has already serviced nearly more than 100 users in Beijing, and effectively promoted the development of regional economies and innovation.
    Research on Laser Measuring Instrument for Tunnel Surfaces
    LI De-Shen, HU Chao-Xu
    2012, 23(1):  74-78. 
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    A laser instrument was designed to measure tunnel surfaces, which used a laser distance measurement component as measuring sensor. The tunnel surface shape and the outline of the object can be measured by the instrument, which can rotate around two mutually perpendicular axes. The measured data was processed and the graphic of the surface shape was generated. The hardware structure and composition of the instrument were analyzed, the hardware circuit was designed and components were chosen. Hardware control software and data processing procedure were designed. An actual surface can be measured to draw out the 3D graphics. The advantages of this instrument were verified that has stable performance, quick measurement and convenient to use in practices.
    Research on High Precision Surface Grinding System for Large Scale Optical Lens
    WANG Zhen-Zhong-1, GUO Yin-Biao-1, LI Ji-2, LEI Xiang-Yang-2, ZHANG Dong-Xu-1
    2012, 23(1):  78-84. 
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    Ultra precision grinding with diamond wheel is widely used for manufacture of large scale optical lens, especially for deterministic batch processing. This paper presented a surface grinding system based on large-scale NC precision surface grinder(MGK7160) to obtain the high machining accuracy, efficiency and automatic level. Then some key technologies, such as diamond wheel truing, dynamic balance, on-machine measurement, CAM software were detailedly realized. The experiments for 400mm*400mm optical lens using 400# grinding wheel were carried out, and the results well reflect that the developed grinding system based on surface grinding machine can perform precision machining of large-scale advanced optical elements with fine reliability.
    Crashworthiness Robust Design for Mobile Hard Disk Based on FEM and Taguchi Method
    YANG Shu-Yi-1, LIU De-Shun-1, DIAO Ji-Yun-2, WEN Ze-Jun-1
    2012, 23(1):  85-89. 
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    Drop impact crashworthiness robust design method was presented based on Taguchi method. A 2.5 inch mobile hard disk finite element modal was built using FEM. The key parameters affecting the crashworthiness robustness were analyzed. The Taguchi method was used to make robust design. Optimal parameters with reducing influence of floor rigidity were acquired. The simulation results show that the crashworthiness of mobile hard disk has been obviously improved comparing with former general parameters. This research work provides theoretic evidence for improving crashworthiness of mobile hard disk.
    Continuous Power Shift Control Strategy of Continuously Variable Transmission System with Reflux Power
    SUN Dong-Shu, YIN Yan-Chi, HAO Yuan-Zhi, LIN Xin-You, LIU Yong-Gang
    2012, 23(1):  89-93. 
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    In order to avoid power loss of continuously variable transmission system with reflux power and reduce vehicle jerk,a continuous power shift control strategy of continuously variable transmission system with reflux power was put forward.Aimed at shifting process,transmission efficiency and the opposite direction of continuously variable unit had impact on transmission output torque,a dynamics model of clutch engagement and disengagement course was established, and the range of clutch torque change ratio was calculated. Taking MATLAB/Simulink as the platform,simulation study of shifting process was carried out, the results indicate that jerk is less than 5m/s3 by adopting continuous power shift control strategy of continuously variable transmission system with reflux power.
    Research on Mechanism and Control Method of Tufted Carpet Stop Mark
    XU Xiang, SUN Zhi-Jun, MENG Chuo, TUN Hai-Chao, SHU Zi-Na
    2012, 23(1):  94-98. 
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    Focusing on tufting machine type of DHGN801D-200, the forming reason of the tufted carpet stop marks were studied and a reasonable approach to eliminate tufted carpet stop marks was put forward. Firstly, the tufting equipment system components and yarn path were introduced. Then, the relationship between yarn path and the flexing of total path was analyzed. According to mechanical property and creep property of yarn, yarn tension change in a typical tufting carpet was analyzed. According to theoretic analysis results, the method of eliminating stop marks was developed,which stopped and restarted machine in the highest positions. Finally, the technology experimental results prove that the method is effective and feasible.
    Predicting Model for Fatigue Life of Mechanical Structures under Random Cyclic Loads
    WANG Zheng, WANG Ceng-Quan, HE Hong
    2012, 23(1):  98-101. 
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    Based on the nominal stress method for fatigue life prediction, a predicting model for the fatigue life of mechanical structures under random cyclic loads was developed herein. The uncertainty of the cyclic loads applied on the mechanical structures was analyzed. With the number of load application as the life index, the fatigue life prediction models of mechanical structures under random cyclic loads were developed with the probability weighted method and the Miner linear cumulated damage rule, when the relationships between fatigue life and stress can be expressed as the exponential function and the power function, respectively. Finally, the models proposed were used to predict the fatigue life of a rotating shaft.
    Research on Key Technologies of Mould Process Collaborative Design over Sharing 3D Transformation Matrix
    WANG Cheng-Yong, JIAN Ling-Yun, CHEN Cong-Sheng, LI Heng, HAN Shu, LIU Quan-Kun
    2012, 23(1):  102-105. 
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    Key technologies of the mould process collaborative design(MPCD) were analyzed under the network environment. Three kinds of process collaborative browse method and its development technologies were comparatively studied. The browse solution of sharing 3 dimensional transformation matrix was put forward. The principles of the mould model network browsing over sharing transformation matrix were discussed. A heterogeneous CAD data lightweight neutral exchange model in the collaborative process consultation system was suggested and the calling and controlling method was researched. The function diagram of the MPCD system based on the new solution was drawn and the prototype experimental system using Java 3D was developed. The three-dimensional transformation matrix, process whiteboard, process command stream multicast and information extraction were detailed. The theory and technology presented herein can provide key support for the collaborative design on the molding and forming process for complex parts.
    Study and Trial Production of Battery Grid Continuous Casting Machine
    LI Mo-Quan-1, GAO Chang-Yin-2, LIU Jiang-1, TAN Ze-Fu-1
    2012, 23(1):  106-108. 
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    A continuous casting machine was designed herein, which had been used successfully for continuous casting battery grids. According to the characteristics of rapid solidification of molten lead in the mold during continuous casting of the grid, battery grid cave in the outer peripheral surface, molten lead passageway in the shoe, temperature control system of mold, gas shielded during the casting were designed. Trial production of continuous casting machine and test of continuous casting were carried out. The sample of grid was obtained successfully.
    Defect Prediction in Coining Process for Au-Ag Commemorative Coins
    ZHONG Wen-1, LIU Yu-Qi-1, HU Jiang-Beng-1, HU Yun-Meng-2, LI Qing-Jiang-2, LAI Mao-Meng-2, SUN Zhi-Guo-2
    2012, 23(1):  109-112. 
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    Flash line, light band and insufficient filling are the main defects in coining process for Au-Ag commemorative coins. Based on a special-purpose FEM software-COINFORM, numerical simulations for coinages were carried out. A radial friction power model was built for the prediction of light band defects. With the analysis of metal flow, the mechanism of flash line was studied on the basis of the experimental results. The former algorithm was improved that the simulation would stop only when the blank was fully contacted with the forming tools in all direction. The reaction force of blank at the stop time predicts the forming force in coining. Experimental results show that the predicted force is valid for eliminating insufficient filling.
    Research on Movement Regularity of Granules during Sheet's Granule Flexible Cavity Forming
    HUANG Qian-Ying, JIA Dun-Ting, FAN Cun-Jie, ZHANG Chun-Xiang
    2012, 23(1):  113-116,125. 
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    The technology of granules or powder soft cavity die forming of sheet was analyzed herein, and the characteristics of forming process were introduced. A basic finite element model of granules soft cavity die forming was established taking wide bending as an example. The physical simulation of granule movement regularity for movement regularity of granules was implied for powder flexible cavity deep drawing technology of cup shell.On the basis of simulation and experimental investigation, basic regularity of granule movement was acquired, and movement zone model was also established. The analysis of granule movement regularity and the establish of movement zone model can present theoretical support for applications of granules or powder flexible cavity forming technology.
    Study on Low-speed Regenerative Braking of Electric Vehicle as ABS Based on Fuzzy Control
    DIAO Guo-Zhu-1, TENG Jian-Hui-2, WEI Min-Xiang-2, YANG Zheng-Lin-2
    2012, 23(1):  117-122. 
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    To make electric car have the function of regenerative ABS during regenerative braking on a road of a low tire-road friction coefficient such as the ice-snow covered road,a novel method was proposed that motor regenerative braking and reversal braking torque were controlled to prevent wheels from locking. The working principle of the low-speed regenerative braking as ABS was described,A single-wheel electric car dynamics model in a braking event was built; regenerative ABS controller was designed based on the circuit steady-state conditions of the low-speed regenerative electric motor and fuzzy control theory. Simulation results indicate that this system is of a satisfactory robustness, a much shorter response time and a superior control accuracy. The braking procedure is composed of a regenerative braking action, being of the main part, and an reversal braking action at the end of the braking procedure. Within motor peak working capacity, the greater the road adhesion coefficient ,the more regenerative ABS's amount of recovering braking energy.
    Road Feel Optimization of Differential Steering of Electric Vehicle with Motorized Wheels
    WANG Chun-Yan-1, 2, DIAO Mo-Zhong-1, 2, DIAO Ting-1, ZHOU Xie-1
    2012, 23(1):  123-125. 
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    Based on the mechanism of a differential steering system for electric vehicle with motorized wheels, the concepts and quantitative expressions of the road feel, sensitivity, and operation stability of the steering were proposed. Then, based on the traditional simulated annealing algorithm, an ASA algorithm was designed. With the road feel of the steering be optimization objectives, and operation stability and sensitivity of the steering be constraint, the system parameters were optimized. The simulation results show that the system optimized with ASA algorithm can improve the steering road feel, and guarantee the operation stability, steering sensibility; thus providing a theoretical basis for the design and optimization of the electric vehicle with motorized wheels system. 