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    Cooperative Control Strategy  of  Power  Following-speed Switching in  a  Range  Extender  Electric  Vehicle APU
    Shen Yongpeng1;Wang Yaonan1;Meng Bumin1;Yi Dihua2
    China Mechanical Engineering    2015, 26 (12): 1690-1696.  
    Abstract1003)      PDF (750KB)(223147)       Save

    To  solve  the  cooperative control problem of the engine and generator in APU system,the speed switching-power  following  APU  cooperative control strategy was proposed  herein.Firstly,the power-speed  switching table  of  the engine was designed  according to  the optimal brake specific fuel consumption(BSFC)  curve.Then,a  second order sliding mode controller of the engine speed was designed,which was based on the engine mean value model.Meanwhile,the PWM rectifier output power  controller  was  designed,which was based  on  the  direct  power  control  algorithm.Through the closed-loop control of the engine speed and PWM rectifier power,the proposed control strategy forced the engine to  run along the optimal BSFC curve.Finally,the joint simulation model   was  developed based on AVL Cruise and MATLAB/Simulink.The simulation results show that the proposed APU cooperative control strategy is excellent  in  aspects of power following and speed controlling accuracy,battery voltage,current  and state of charge(SOC) fluctuations,as well as the operating points distributions.

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    Economic Shift Rule for Medium HEV with AMT
    Qing Datong1;Long Haiwei1;Hu Minghui1;Ye Xin2
    China Mechanical Engineering    2013, 24 (20): 2820-2825.  
    Abstract698)      PDF (761KB)(69905)       Save

    Based on a medium HEV with an AMT, the work area was gained with maximizing systematic efficiency as objective, by comprehensively considering the efficiency of the engine, motor/generator, battery and transmission system. And then the economic shift rule under driving conditions was obtained after analyzing the economic shift rule of each working mode. The simulation of the proposed economic shift rule was carried out on the platform of MATLAB/Simulink under cycle condition of ECE+EUDC. The results indicate that it can improve the fuel economy of medium HEV compared to the traditional shift rule of ADVISOR.

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    Analysis and Optimization of Steering Mechanism for Rhombic Vehicle
    CHA Yun-Fei, ZHONG Zhi-Hua, YAN Xiao-Lei
    China Mechanical Engineering    2010, 21 (8): 935-939.  
    Abstract1402)      PDF (3519KB)(22094)       Save
    A space kinematics equation of the front wheel’s steering rod mechanism was built through the steering rod mechanism of the rhombic vehicle that was symmetrical about front and rear.The virtual prototyping model was built by utilizing the dynamics analytical software ADAMS of mechanical system.It validated the kinematics equations’ correctness.Considering the length and initial location of the wheel links, the relation of steering angles when the wheel turned left and right was optimized as well as the variation of steering angle during the wheel bounded based on the genetic algorithm.According to the requirements of the rhombic vehicle,the length and initial location of the corresponding links were optimized,which provides a theoretic basis to the design of steering mechanism.
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    Intelligent  Manufacturing——Main Direction  of "Made  in  China 2025"
    Zhou Ji
    China Mechanical Engineering    2015, 26 (17): 2273-2284.  
    Abstract3024)      PDF (1586KB)(18016)       Save

    How to transform from a big nation in manufacturing  to  a  powerful one is a great subject of China's  economic development in the new era.This paper discussed  the guiding ideology,strategic deployment,basic policy and strategic measure of “made in China 2025” based on detailed analyses of current manufacturing situations  of China,and indicated  that “Internet+advanced manufacturing+modern service industry” will become a new engine of China's economic development.It  is pointed  out that digitization,networking and  intellectualization of manufacturing industries  are the core technologies of  a new round industrial revolution, and should be used as commanding point,breakthrough and main direction of  “made in China 2025”.An overall thorough interpretation of above points was put forward.

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    Finite Element Mesh Generation and Decision Criteria of Mesh Quality
    LI Hai-Feng-1, TUN Ji-Chuan-2, LIU Jian-Bei-1, LIANG Yu-Bing-1
    China Mechanical Engineering    2012, 23 (3): 368-377.  
    Abstract1107)      PDF (684KB)(10344)       Save
    Some general problems in mesh generation were discussed, the demands of mesh generation were expounded, the mesh generation methods were introduced, the mesh generation algorithms in last ten years were retrospected and their advantages and disadvantages were compared. Based on the requirements of practical engineering calculation,the authors brought up the mesh quality demands and decision index, explored the mesh quality optimization, introduced the preprocessors and their applications of the commercial softwares,then gave out several practical examples of the mesh generation. At last, the trends of mesh generation were also presented.
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    Mammalian Legged Robot:a Review
    QIN Xian-Sheng-1, 2, ZHANG Xue-Feng-1, TAN Xiao-Qun-1, FENG Hua-Shan-1, ZHANG Pei-Pei-1
    China Mechanical Engineering    2013, 24 (6): 841-851.  
    Abstract806)      PDF (825KB)(10037)       Save

    For discrete ground contact,there were high adaptability and extensive application prospect for mammalian legged robot when encountering special topographical and unpredictable environment such
    as obstacles,ditch and so on.This paper surveyed the development process of mammalian legged robots,and mainly introduced overseas and domestic research status in terms of two legged and four legged robots.The related theory and method on legged structure,joint drive,navigation,stability criterion and control algorithm  were analyzed and discussed,Meanwhile,the difficulties to be solved under development were analyzed and the future of legged robots was forecasted.

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    Current Status and Development Trends of Vibration-based Piezoelectric Generator
    SHU Chi-Ya, CHEN Ren-Wen, LEI Xian
    China Mechanical Engineering    2011, 22 (24): 3016-3022.  
    Abstract1128)      PDF (609KB)(8068)       Save
    The current status of piezoelectric generator was reviewed,including the working principles and the species of piezoelectric elements.The energy scavenging circuits and the strategies for increasing the operating frequency range were focused.
    Some application examples were illustrated and the trends were pointed
    out according to the problems in current researches.With the development of microelectronic and micromachining technology,the piezoelectric generators will be widely used in powering MEMS,wireless sensor networks and low dissipation electronic devices.
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    Numerical Simulation of Hydrodynamic Coefficients of Crane Ship Based on CFD
    HUANG Chang-Jing, WANG Hua-Lin, HU Xu-Jin
    China Mechanical Engineering    2011, 22 (17): 2076-2079.  
    Abstract1114)      PDF (524KB)(7668)       Save
    In order to estimate the added mass and damping of a crane ship, the numerical simulation of the heave, sway and roll motion of the ship was performed based on CFD theory. The sliding faces and the mixed grid approach were used herein. A hydrostatic roll experiment of ship model was carried out. Comparing the experimental measurement with numerical results, the feasibility of CFD simulation used to predict the hydrodynamic coefficients of the crane ship is demonstrated.
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    Neural Network-based Robust Tracking Control for Nonholonomic Mobile Robot
    Peng Jinzhu;Wang Yaonan;Yu Hongshan
    J4    2008, 19 (7): 0-761.  
    Abstract2179)      PDF (3866KB)(7532)       Save

    To deal with the unknown factors of nonholonomic mobile robot, such as model uncertainties and external disturbances, a robust controller with bounded estimation based on neural network was proposed. The knowledge of dynamics parameters and external disturbances of the mobile robot were assumed to be unknown. The proposed controller can overcome the uncertainties and the disturbances. And the stability of the proposed controller was proven by using Lyapunov function. The simulation results demonstrate that the proposed method has good robustness and adaptation.

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    Design for Basic Rack of Harmonic Drive with Double-circular-arc Tooth Profile
    XIN Hong-Bing
    China Mechanical Engineering    2011, 22 (6): 656-662.  
    Abstract1131)      PDF (643KB)(7060)       Save
    On the basis of research on engagement principle of harmonic drive with circular-arc tooth profile, a design method was presented for double circular-arc tooth profile of basic rack for flexspline and rigid spline of harmonic drive. The double circular-arc tooth profiles of basic rack ensured the tooth profiles of flexspline and rigid spline to keep on conjugating with each other during the meshing period, especially there existed so-called dual-conjugated meshing zones, in which the convex and concave profiles of flexspline conjugated with the concave and convex profiles of rigid spline simutaneously, this characteristics played important roles in improving the torsional stiffness and transmission accuracy of the harmonic drive. The double-circular-arc tooth profiles of basic rack of harmonic drive with elliptical wave generator were developed and applied in design and manufacture of the hobs with double-circular-arc tooth profile for flexspline, the shaping cutters with double-circular-arc tooth profile for rigid spline and the sample device for experimentation. Compared with the involute profile, the flexible strength, transmission accuracy, and torsional stiffness of the harmonic drive with double-circular-arc tooth profiles are markedly improved. 
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    Modeling and Simulation of a Piezoelectric Stacked Generator
    Wang Guangqing
    J4    2009, 20 (19): 0-2274.  
    Abstract1209)      PDF (5568KB)(7002)       Save

    A piezoelectric generator based on the piezoelectric stack electro-mechanical energy conversion was proposed. The electro-mechanical coupling model of the generator and the relationship between the deduced voltage and the exciting force of the stack were deduced based on the piezoelectric vibration theory and one-dimensional wave theory. The effects on the power performance of piezoelectric stack physical parameters, such as the amplitude and frequency of the force, the mass and the stiffness of the mechanical system were studied. The research results show that the bigger the force, the larger the power ability, and when the frequency of the exciting force is according with the resonant frequency of the generator, the power ability of the generator is maximum. And if the length and area of the piezoelectric stack is suitable for the resonant frequency of the generator, the power ability is maximum. Moreover, if the load impedance matches the equivalent impedance of the generator, the electro-mechanical energy conversion efficiency of the generator is maximum.

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    A Revised Solution for Moment-deflection Relation of Torsion Spring
    LI Bao-Fu, LIU Beng-Fang, FAN Dun-Wei
    China Mechanical Engineering    2010, 21 (19): 2318-2321.  
    Abstract1881)      PDF (3033KB)(6613)       Save
    The interaction between a helical torsion spring and its accessories (spring seats and spindle) was investigated with finite element contact analysis. The result of simulation shows that the twist deformation of the spring can be divided approximately into several stages by the variety of contact regions between the spring parts. Accordingly, a piecewise linear relation of moment-deflection was established based on elementary theory of beam. It has been proved that the equations present herein are more precise than the classical algorithms which take no account of the effect of spring accessories.
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    Brief Analysis of a BigDog Quadruped Robot
    DING Liang-Hong, WANG Run-Xiao, FENG Hua-Shan, LI Jun
    China Mechanical Engineering    2012, 23 (5): 505-514.  
    Abstract1618)      PDF (681KB)(6489)       Save
    Based on the current technical information of a BigDog quadruped robot which was released, the overall profile and the core technology of the BigDog robot were analyzed herein. Structural characteristics, motion characteristics and high power density issues arising from these were analyzed emphatically in the mechanical system. The basic components of the BigDog's hydraulic drive system were analyzed briefly. Biomimetic structure defects restricted the BigDog's maneuverability to further promotion. In rough terrain, the motion control of BigDog firstly depends on the detection of body posture and perception of the terrain. Security posture is the prerequisite for BgDog's continuous longitudinal motion. The basic walking control algorithm was analyzed briefly. The output characteristics of the hydraulic system just meet BigDog's dynamic requirements. Control implementation process was known by analyzing several typical states of motion. Navigation system of BigDog, in particular fully autonomous navigation part is the emphasis. In unstructured environments, the intelligence of mobile robot mainly depends on the design of navigation system. At last, based on author's research experience on quadruped robot, some suggestions of the research and development on the quadruped robot were proposed.
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    Hydraulic Power Systems for Trunk Line Aircrafts
    Yang Huayong;Ding Fei;Ouyang Xiaoping; Lu Qing
    J4    2009, 20 (18): 0-2148.  
    Abstract1670)      PDF (7837KB)(6195)       Save

    The background of developing large commercial aircraft was given.The hydraulic power systems of popular and new type commercial aircrafts from Airbus and Boeing Company were introduced. The future trends of hydraulic system for civil aircraft were outlined, namely high pressure, distributed system,DPHM(diagnostics,prognostics and health management),boostrap reservoir and intelligent pumping source system. The hydraulic power systems of A320
    and B737 were compared and the two proposals of hydraulic power system for China commercial aircraft were brought forward. The key techniques of developing commercial
    crafts, namely high reliability, pressure pulsation control, temperature control and contamination control were indicated.

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    Comparison between ISO and AGMA Gear Strength Rating Methods for Involute Cylindrical Gears
    TUN Chang-Lin, LV Yun-Fei
    China Mechanical Engineering    2011, 22 (12): 1418-1423,1465.  
    Abstract1098)      PDF (549KB)(5513)       Save
    Comparative analysis of involute cylindrical gear strength rating methods used by ISO standard and AGMA standard was conducted.Gear parameters and derating factors were classified.Differences between the meaning and selection of gear parameters and derating factors,as well as their effects on gear rating results,were analyzed through calculations.The study indicates that neither of the two standards is more conservative than the other one, and the bending strength rating results of AGMA standard are more sensitive to the change of gear geometry parameters.The study also indicates that different values of parameters and derating factors cause the differences in gear rating results of the two standards.The allowable stress number,load,geometry parameters and life have the most significant effects on pitting resistance rating results; while the stress correction factor relevant to the test gears, load and geometry parameters have the most significant effect on bending strength rating results.
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    Digitization and Intellectualization for Manufacturing Industries
    ZHOU Ji
    J4    2012, 23 (20): 2395-2400.  
    Abstract969)      PDF (608KB)(5504)       Save

    This paper holds that,first of all,as the world economic competition framework is undergoing profound changes,major developed countries have proposed the strategy of “reindustrialization”,putting forward significant measures to revitalize manufacturing industries dependent on scientific and technological innovations.A new round of industrial revolution is deepening.The author continues to argue that,the digitalization and intellectualization of manufacturing industries can be viewed as key technologies for the new round of industrial revolution.On the one hand, they are the generic enabling technologies for the realization of mechanical products innovation,developing mechanical products towards “NC generation” and “intelligent generation”,boosting the functions,overall performance as well as market competitiveness of them fundamentally.On the other hand,they are the generic enabling technologies for the manufacturing technology innovation,developing manufacturing industries towards integrated manufacturing system featuring digitization and intellectualization, promoting the products design,manufacturing as well as management levels comprehensively,with the manufacturing service industry being developed at the same time,thus reforming the production mode and industrial pattern & structure of manufacturing industries greatly.Last but not least,the author believes that,the next twenty years can be regarded as a period characterized by precious opportunities of strategic importance,for China to transform from being a “big nation in manufacturing” to a “powerful nation in manufacturing”.China's manufacturing industries should and are most likely to make leaping progress during this time span,especially to make strategic breakthroughs in “digitization and intellectualization of manufacturing industries”,thus making historical contributions for the modernization of China.

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    A Trajectory Planning Method for Cubic Uniform B-spline Curve
    MAO Zheng-Yu, LIU Zhong-Jian
    China Mechanical Engineering    2010, 21 (21): 2569-2572,2577.  
    Abstract1801)      PDF (3826KB)(5464)       Save
     A new interpolation method was presented to satisfy the requirements of CNC machining for complicated curves. Firstly, the proposed method used cubic uniform B-spline segments based on a real-time overlapping combination algorithm to fit complicated curves, and then an adaptive algorithm was provided to calculate the interpolation step size through taking the chord error, velocity and acceleration into consideration, which can provide a good performance for improving the contour accuracy and reducing the impact on machine.At last, a trajectory planning strategy was put forward to guarantee the trajectory in the interpolation process meeting the smoothed constraints of velocity, acceleration and jerk. The simulation results of interpolation experiments show that the presented method can ensure high-speed and high-accuracy of machining complex curves, and has a good smooth feature of velocity, acceleration and jerk. This method feasibility has already been proved in real CNC system.
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    Current Actuality and Development Tendency of Military Camouflage Technology
    YA Yun-Hui, WANG Zhan, DONG De-Wei
    China Mechanical Engineering    2012, 23 (17): 2136-2141.  
    Abstract1076)      PDF (509KB)(5455)       Save

    Through introducing meaning of camouflage technology, the importance and significance could be understood in the modern war. Several technology of military camouflage areas and its principles and applications were illustrated in detail,including screen camouflage technology,decoy camouflage technology,color camouflage technology, etc. The current situation was discussed on the development of world military camouflage. With the development of technology, it is expounded that camouflage technology is developing towards multiband, pluralism, intelligence. With the applications of more discipline theory, camouflage technology will blend in new methods and new ideas. 

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    Real-time Solution of Inverse Kinematics Problem of Multi-joint Robots
    YI Feng, WANG Yao-Na, JIA Han-Min
    China Mechanical Engineering    2010, 21 (10): 1143-1148.  
    Abstract1474)      PDF (4081KB)(5390)       Save
    Due to the highly nonlinear and complex nature of the manipulator kinematic equations, the solution of the inverse problem is difficult to achieve and it
    is difficult to guarantee in real-time.A new method for computing solutions to the inverse kinematics of robotic manipulators was developed herein.The proposed method was
    based on an EM algorithm,by randomly sampling points from the feasible region, similar to attraction-repulsion mechanism of the electromagnetism theory,the particles rapidly converge to optimal solution.Moreover,approximate optimal solution derived by EM was used for the initial guesses value of variable metric method to search the exact solution. Nevertheless, the exact optimal step size in search is usually difficult to achieve.For this problem, approximate formulas for calculating were derived based on motion differential equation of robot when step size was sufficiently small.Finally,some examples were taken to verify the effectiveness of the algorithm.
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    Research Progresses of ELID Mirror Grinding Technology
    YIN Shao-Hui, CENG Xian-Liang, FAN Yu-Feng, SHU Yong-Jian, TANG Hun
    China Mechanical Engineering    2010, 21 (06): 750-755.  
    Abstract1534)      PDF (4754KB)(5335)       Save
    As a low cost and high efficiency ultra-precision mirror processing technology-ELID mirror grinding technology, is widely used in the field of modern ultra-precision machining.This paper summaried the historical development and the present research situation of ELID mirror grinding technology, introduced to the processing mechanism of the technology and the formation of mirror surface,as well as focused on several different forms of the ELID mirror grinding under different conditions. Lastly a prospect of the in-depth research of the technology and some problems of the industrialization promotion were proposed.
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    Research on a Novel Piezoelectric Type Electro-pneumatic PWM Proportional Valve
    Xu Youxiong;Li Xiaoning
    J4    2009, 20 (14): 0-1703.  
    Abstract1302)      PDF (6636KB)(5185)       Save

    The traditional electro-pneumatic PWM(pulse width
    modulation) proportional valve driven by electro-mechanical converter of electromagnet has the disadvantages of slow response and poor control precision etc.To solve this
    problem,a novel piezoelectric electro-pneumatic PWM proportional valve driven by the electro-mechanical converter of piezoelectric stack was presented,where its displacement
    was amplified by the amplification mechanism based on flexure hinges.Then the
    mathematical model of PWM proportional valve was set up.On this basis,a prototype was fabricated and its related test was researched.The effect of PWM carrier frequency,proportional control coefficient and flow load on the valve performance was analyzed. And the compound control method combined with pressure feedback,P control and PWM was applied to enhance the steady precision of valve.The experiments indicate that the valve has fast response and high steady precision,with good industrial application prospect.

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    Cargo Pendulation Analysis of Moored Crane Ship under Regular Waves
    WANG Hua-Lin, YOU Xin-Yi, HU Xu-Jin
    China Mechanical Engineering    2010, 21 (9): 1077-1082.  
    Abstract1554)      PDF (3993KB)(4676)       Save
    An eight-degree-of-freedom time domain mathematical model was used to simulate moored crane ship dynamics numerically. This model considered large-amplitude load swing of the hull, hydrodynamic memory effects, nonlinear drag forces acting on the hull, wave forces, and nonlinear restoring force characteristics of a mooring system. The dynamics of a crane ship was investigated for two different external excitations: the idealized case of purely harmonics pitching motion of the ship and force acting on the hull due to incoming regular waves. The results indicate that the large resonant oscillations may occur if the wave frequency approaches one of the system’s eigenfrequencies. The load swing angle range is obviously affected by nonlinearity of the restoring force of the mooring system.
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    Adaptive Piecewise NURBS Curve Interpolator Algorithm for Entireness Process S-curve ACC/DEC Control 
    BO Hai-Hong, YANG Wei, CHEN Lin, TAN Hua-Qing, SUN Gong-Chao
    China Mechanical Engineering    2010, 21 (02): 190-195.  
    Abstract1442)      PDF (4863KB)(4283)       Save
    Adaptive Piecewise NURBS Curve Interpolator Algorithm for Entireness Process S-curve ACC/DEC Control 
    An adaptive piecewise NURBS curve interpolation algorithm based on 7-segment S-curve ACC/DEC control along the entire curve was present to meet the requirements of the modern CNC high-speed and high-precision machining.The algorithm adaptively divided a NURBS curve into small segments according to the information of the
    curve geometry, and calculated the value of the parameters of the curve segments.This algorithm adaptively adjusted the ACC/DEC time of the velocity curve,which was corresponding with the 17 kind of types of the S-curve ACC/DEC conditions.At a fixed interpolation cycle, compared the proposed algorithm with alone adaptive algorithm and 5-segment S-curve ACC/DEC control method, the simulation and analysis results show that the interpolation precision of the proposed algorithm is higher than that of the alone adaptive interpolation method, and is approximate to the 5- segment S-curve ACC/DEC control method under the limitations of acceleration and jerk and the maximum chord height error being less than 0.5μm. Furthermore, the average feed rate along the full curve of the proposed algorithm is increased by 21.7%,compared with that of the 5-segment S-curve ACC/DEC control method,and which can reach 594mm/s.
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    Ultra-precision Grinding Technology and Grinder of Silicon Wafers
    SHU Xiang-Long, KANG Ren-Ke, DONG Zhi-Gang, GUO Dong-Meng
    China Mechanical Engineering    2010, 21 (18): 2156-2164.  
    Abstract1323)      PDF (5779KB)(4235)       Save
    The advances of surface grinding technology and grinder of silicon wafers were introduced based on the development of silicon wafers. The grinding principles and the characteristics of representative grinders widely using for silicon wafer grinding technologies, i.e., rotary table grinding, wafer rotation grinding, and double-side grinding, were comparatively analyzed. The latest advances of low-damage grinding technologies for silicon wafers back thinning and planarization were discussed and the trend of the wafer grinding technology was prospected.
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    Auto-body NVH Structure Sensitivity Analysis Based on Modal Analysis Method
    Yang Bo;Zhu Ping;Yu Haidong;Han Xu
    J4    2008, 19 (3): 361-364.  
    Abstract3192)      PDF (4190KB)(4026)       Save

    A SUV auto-body noise,vibration,and harshness(NVH) structure sensitivity was analysed,considering the structure-acoustic coupling based on the modal analysis method.The structure and acoustic vibration mode were gained from coupling analysis while inner noise level from frequency analysis.The given methods reduce noise by identifying the main source to the noise through structure sensitivity analysis.

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    Research on Multi-objective Topology Optimization on Bus Chassis Frame
    Fan Wenjie;Fan Zijie;Su Ruiyi
    J4    2008, 19 (12): 0-1392.  
    Abstract1805)      PDF (3376KB)(3916)       Save

    This paper presented a multi-objective topology optimization method for bus chassis frame, in which both the compliance and eigenfrequencies were regarded as static and dynamic optimization objectives.Based on the SIMP(solid isotropic material with penalization) method,compromise programming method was adopted to define objectives of multi-objective topology optimization and multi-stiffness topology optimization,mean frequency method was adopted to settle eigenfrequencies of free vibration optimization.This approach overcomes the shortcoming of single-objective optimization methods which can not simultaneously consider other objectives and suits to multi-objective topology optimization of continuum.

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    Proportional Electromagnetic Valve Driven by Frequency-varying PWM
    Kang Jian, Shang Shasha, Jiao Wenxue, Wang Xing, Pu Dingchao, Niu Zhen, Ye Qituan, Wang
    China Mechanical Engineering    2015, 26 (8): 1024-1028.  
    Abstract593)      PDF (551KB)(3870)       Save

    In applications of  excavator or other industrial machines, proportional electromagnetic valve was usually driven by PWM signals of embedded control system. However, due to pulse output characteristics of electromagnet, the performance of proportional electromagnetic valve was limited, even impacted stability of the system. A frequency-varying method of PWM driving was proposed. According to different duty ratio of PWM, the embedded control system output PWM with different frequencies. Through this method, the output oil pressure of proportional electromagnetic valve maintains within a determinated range, the valve-core's zero-average oscillations is reserved and power consumption of proportional electromagnetic valve is relatively low.

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    Stability Analysis of Hydrodynamic Journal Bearing System Based on Sommerfeld Number
    XU Wu-Ban, WANG Tian-Jiang, CHEN Ji-Bing, LI Bing, ZHANG Hong-Xian
    J4    2009, 20 (23): 2875-2879.  
    Abstract3422)      PDF (4437KB)(3804)       Save
    The stability analysis method of hydrodynamic journal bearing system based on non-linear oil film force was presented, in which the approach to determine the stability of the system and the mathematical calculating method were introduced. A dimensionless Sommerfeld number was utilized to express the system synthetical parameters. By the Sommerfeld number, the stability and the dynamic characteristics of hydrodynamic journal bearing system can be easily calculated, and a dimensionless stability map of a rigid and symmetrical journal bearing system was presented as an example.
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    Research on Operation Smoothness and Noise of Stepping Motor Based on New Type Acceleration/Deceleration Curve and Real-time Control Scheme
    LI Xiao-Hu, WANG He, HU Jia-Lin
    China Mechanical Engineering    2012, 23 (16): 1907-1911.  
    Abstract713)      PDF (531KB)(3616)       Save

    Based on acceleration/deceleration curves and control scheme,the operation smoothness and noise of stepping motor were analyzed and studied.According to the relation between angular acceleration and angular velocity (a-ω equation),the S-type,e/e-type and Cos-type acceleration/deceleration curves were constructed respectively,in which the flexible impact can be avoided.Then,the control scheme of stepping motor was optimized, including that the smoothness of stepping motor's speed transition was improved,that the controller's calculation speed was enhanced because of calculation's simplification by iterative algorithm,and that storage resources were saved through real-time calculation.The noise experimental results show that compared with the traditional drive scheme,the stepping motor system,which adopts Cos-type acceleration/deceleration curve and real-time control scheme,operates smoothly and has lesser noise during startup process.

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    #br# A Customer Needs Importance Rating Method Based on Fuzzy Kano Model
    BAI Chao, LI Zhong-Kai
    China Mechanical Engineering    2012, 23 (8): 975-980.  
    Abstract825)      PDF (489KB)(3546)       Save

    Aiming at the problems of lacking classification capability in customer needs rating calculation,a customer needs classification and importance rating method based on fuzzy Kano model was proposed.The customer survey data were counted and analyzed with the fuzzy Kano model the customer needs were divided into three types such as must-be,one-dimensional and attractive.At the same time,
    the adjustment functions of customer needs importance were introduced,the customer needs category could be combined with the related importance calculation to guide enterprises getting the maximum customer satisfaction with the minimum cost input.The effectiveness of the proposed method was illustrated by the customer satisfaction evaluation of an enterprise's combine harvesters.

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    Uncertainty Analysis of Flexible Multibody Systems Using Polynomial Chaos Methods
    PI Ting, ZHANG Yun-Qing, TUN Jing-Lai
    China Mechanical Engineering    2011, 22 (19): 2341-2343,2348.  
    Abstract1629)      PDF (469KB)(3489)       Save
    A parametrical uncertainty analysis of flexible multibody systems was presented. The deformations of flexible parts were modeled using ANCF. Polynomial chaos methods were employed to solve ANCF-based flexible multibody systems with random variables. Theoretical analysis and numerical examples were made to compare the accuracy and efficiency of polynomial chaos methods and Monte Carlo simulation method. Results show that polynomial chaos methods are more effective than Monte Carlo simulation to achieve the same accuracy in solving complex flexible multibody systems. 
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    Study on Ultrasonic Vibration Precision Machining Technology of Aircraft Fastener Holes
    ZHANG De-Yuan, LIU Jing
    China Mechanical Engineering    2012, 23 (4): 421-424.  
    Abstract971)      PDF (529KB)(3438)       Save
    A kind of ultrasonic drill-reaming-countersink machining method and rotary ultrasonic vibration drilling tool system were proposed and developed,in order to solve a series of problems,such as long machining process route,low machining quality and low tool life for traditional manual multi-step drilling fastener
    holes on CFRP and titanium alloy stacks of aircraft skin.Experiments show that ultrasonic machining tools and method can obviously improve the quality and the processing efficiency of fastener big holes on CFRP and titanium alloy stacks and lower the production cost to satisfy the aircraft assembly industry requirements. 
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    Joining Strength Comparison among Self-piercing Riveting,Clinching and Resistance Spot Welding
    HUANG Zhi-Chao, LIU Xiao-Kun, JIA Lian-Jun, TIE Jin-Jing
    China Mechanical Engineering    2012, 23 (20): 2487-2491.  
    Abstract618)      PDF (523KB)(3425)       Save

    Self-piercing riveting,clinching and resistance spot welding were described by joining Q195 steel sheets and 5A05-O aluminum sheets respectively.The tensile tests and failure modes were also analyzed.The results show that the joint of resistance spot welding have higher static strength than the other two joints when steel sheets are joined;while the joint by self-piercing riveting have the best strength when aluminum sheets are joined.The joining strength of steel sheets is about 2~4 times larger than that of aluminum sheets for the same jointing technology. 

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    Research on PCB Collision Based on ABAQUS/Explicit Dynamic
    LIU Zhi-Feng, ZHANG Jing-Dong, CHENG Huan-Bei
    China Mechanical Engineering    2012, 23 (12): 1456-1461.  
    Abstract728)      PDF (626KB)(3296)       Save

    The theories of central difference arithmetic,stable time'slimit and the theory of energy balance were analyzed systematically,the impact of stable time's limit and energy balance due to
    mechanical parameters of materials such as stiffness,density and mesh
    density was researched.Then a finite element model was built and the method of
    Wheatstone bridge was used to validate model's accuracy.Finally,a detail research on PCB collision was made based on the experiments and simulation,it indicates
    that ABAQUS/Explicit can deal with the impact load precisely.The calculation cost will be reduced and the precision will be satisfied as well by applying the theory of energy balance,the strength of the packaging meets the reliability requirements of PCB.

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    Establishment of Jacobian Matrix and Singularity Analysis of a 6-DOF Installing-calibrating Robot
    LI Cheng-1, XIE Zhi-Jiang-1, NI Wei-2, LIU Nan-2
    China Mechanical Engineering    2012, 23 (10): 1165-1169,1174.  
    Abstract683)      PDF (581KB)(3269)       Save

    Aimed at a 6-DOF installing-calibrating robot,coordinate systems of joints were set up and D-H parameters were obtained by using D-H methods.Then the positions of its moving elements and end-effectors with their relationship were presented and the forward kinematic solution were derived.A Jacobian matrix of  the installing-calibrating robot was established based on differential methods.And singular values of the Jacobian matrix and the condition numbers of installing-calibrating robot were analyzed.It provides the theoretical basis and important data for the robot trajectory planning and online real-time calculation under actually working environments.

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    Research on Active Heave Compensation Control of Remotely Operated Vehicle
    YANG Wen-Lin, ZHANG Ai-Qun, ZHANG Du-Yang, WEI Su-Fen
    J4    2009, 20 (23): 2777-2781.  
    Abstract3383)      PDF (3849KB)(3264)       Save
    The heave motion of supporting ship affects the launching
    and recovering of remotely operated vehicle(ROV).Active compensation control of hydraulic winch was used to improve the launching and recovering safety of ROV by reducing the heave speed of tether management system (TMS). The model of hydraulic winch was built and active heave compensation feedforward control was set up. Active heave compensation tests of ROV indicate that non-linearity of hydraulic winch decreases the efficiency of active heave compensation. Hydraulic winch active heave compensation predictive control was designed. Simulation test shows that hydraulic winch active compensation predictive control with parameters identification of hydraulic system improves the efficiency of heave compensation.
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    Fault Diagnosis for Rotor System Based on Volterra Series
    Tang Hao; Qu Liangsheng;Wen Guangrui
    J4    2009, 20 (04): 0-388.  
    Abstract1332)      PDF (1517KB)(3229)       Save
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    Study and Development of Mobile Robot’s Control Framework
    Li Wenfeng, Zhang Fan, Yan Xinqing, Yang Xiaozhu, Du Juan, Han Rui
    China Mechanical Engineering    2008, 19 (1): 114-119.  
    Abstract3107)      PDF (4460KB)(3223)       Save

    Based on the discussion of features and applications of mobile robots, a survey of their researches was made from the viewpoint of the technologies of their control framework and autonomy. Then control modes and popular systems of mobile robots were discussed and the relative advantages and disadvantages were summarized. The characteristics of the control frameworks of mobile robots were concluded and a few of existing control frameworks were analyzed. According to the development of sensor networks, the combination and cooperation of mobile robots and sensor networks was predicted and the challenges that control frameworks of mobile robots must face to work with sensor networks were pointed out, and a new and reasonable one was put forward at the end.

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    Compound Method of Rotor Speed Self-sensing for a Bearingless Permanent Magnet Synchronous Motor
    HU Bei, SHU Huang-Qiu, JI Wei
    China Mechanical Engineering    2013, 24 (14): 1927-1932.  
    Abstract501)      PDF (608KB)(3202)       Save

    Because one method cannot obtain precise estimation of rotor speed and position in full speed, a compound method using high frequency signal injection and SMFEKF was proposed to estimate the rotor speed and position for a BPMSM herein. When the motor worked at state of zero and ultra-low speed, high frequency signal injection was used, which was based on motor space-saliency effect; at the high speed of the drive, SMFEKF was used. SMFEKF has strong robustness of the model mismatch and unique strong tracking ability, which can improve the tracking performance effectively to steady-state and mutation status. By designing speed switch, smooth switching was achieved. The sensorless vector control system of BPMSM was set up based on this estimation approach. Simulation study demonstrates that the proposed method is capable of precisely estimating rotor speed and position in full speed, high robustness is achieved under the conditions of step response or load disturbance.

     

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    An Algorithm of Sampled-data Linear and S shape Acceleration and Deceleration for CNC Controller
    CHEN You-Dong, WEI Hong-Xin, WANG Qi-Kuai
    China Mechanical Engineering    2010, 21 (05): 567-570.  
    Abstract1184)      PDF (2895KB)(3169)       Save
    A new method of sampled-data linear and S-shape acceleration/deceleration for industrial robots and CNC machine tools were put forward, which eliminated the running stage at low speed for a long time after deceleration because the actual deceleration point did not overlap the theoretical deceleration point. The velocity of iterative formula for acceleration/deceleration was proposed. The velocity was recalculated based on the acceleration so that the distance was exactly the integral times of the velocity. The acceleration and jerk was recalculated based on the velocity. It avoided the prediction of the deceleration point by every sampled time. The simulation and experimental results demonstrate that the proposed method can eliminate the running stage at low speed for a long time and significantly improve the productivity by avoiding the prediction of decelerating point.
     
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