Table of Content

25 April 2015, Volume 26 Issue 8

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Optimization Design  of  Notches in Spool Valve Based  on PSO Algorithm

Li Weijia, Lan Qiuhua, Peng Yong, Yi Disheng

2015, 26(8):  995-999. 

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Optimization design of three basic notches including single-U-shaped, ramp-U-shaped and V-shaped was investigated thoroughly. Fluent, the flow field simulation software, was used to calculate the flow of different notches at different displacements in the constant pressure, and the experiments were done to make sure the reliability of the simulation results  from Fluent by the comparison of simulation results with experimental ones. And it is found that the flow gradient of single-U-shaped notch decreases with its displacement increases, the flow gradient of V-shaped notch basically unchanges with its displacement increases, and the flow gradient of single-U-shaped notch increases with its displacement increases. Using the PSO algorithm and combining some notch simulation calculation results, the optimal sizes of notches were obtained, which could meet the required displacement flow characteristics good effectiveness. And one case that the required displacement flow characteristics verified that the optimization algorithm has high precision, compared with simulation results from optimal sizes.

Analysis of HSK Toolholder-spindle Interface Contact Characteristics and Its Effects

Liu Xuemei, Li Aiping, Tan Shunli

2015, 26(8):  1000-1005. 

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This  paper was  undertaken to analytically investigate the performance of the HSK toolholder-spindle connection and spindle system with FEM.The analysis results show that spindle speed has become the major influence factor on the contact area at high rotational speed, and that the contact area decreases with increasing spindle speed. The results also show that the contact stress is significantly affected by clamping force, and that increasing clamping force causes the contact stress to increase and the contact stress distribution to change in case of constant spindle rotational speed and interference magnitude. It is also observed that spindle-holder interface dynamics mainly affects the vibration mode and harmonic response. The inherent frequency decreases and the amplitude increases after considering the effects of the toolholder-spindle interface on spindle system.

Study on Mechanics Characteristics of 3-DOF Same-stiffness Permanent Magnetic Spring

Sun Feng, Zhang Ming, Sun Xingwei, Jin Junjie, Li Qing, Li Dianqi, Wang Ke

2015, 26(8):  1005-1009. 

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This paper presented a 3-DOF same stiffness permanent magnetic spring. According  to the structure, the mathematical model  of permanent magnetic spring was set by virtual displacement method. The model of the spring's radial magnetic force was calculated by the mathematical model and FEM software, the calculated results are basically in agreement with the simulation results. The results show that the radial magnetic force of the permanent magnet spring increases with increasing the radial displacement, decreases with increasing the axial displacement. In translational plane, the stiffness coefficients of two moving directions and the rotational direction are equal. When the radial displacement is small, the relationship between the radial displacement and spring stiffness coefficient is approximately linear.

Research on Design and Experiment of a Biomimetic Undulating Fin Propeller Actuated by SMA Wires

Wang Yangwei, Yu Kai, Wang Zhenlong

2015, 26(8):  1010-1014. 

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A study about a biomimetic undulating fin propeller actuated by SMA wires was presented. Firstly, the structure and function of muscular hydrostats of cuttlefish fin were analyzed, and the kinematic model of the cuttlefish's fin undulatory motion was  built. Secondly, a biomimetic undulating fin propeller actuated by SMA wires was developed. Finally, the hydrodynamic performance of the biomimetic propeller was tested. The results show that the flexible fin undulatory motion of biomimetic propeller is similar to fin of cuttlefish. The undulatory amplitude and thrust increases with increasing the actuating pulse width. The instantaneous  maximum thrust is 180mN at actuating pulse width 80ms.

Dynamics Modeling and Simulation of Three-link Flexible Manipulator on Vertical Plane

2015, 26(8):  1014-1018. 

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For solving problem of lower accuracy induced by common methods in flexible manipulator dynamics modeling, such as FEM  etc., flexible manipulator was considered as a continuous whole and its dynamics model was built by vector method. Simulation results of dynamics model of flexible manipulator under vector method and FEM, and dynamic model of ideal rigid manipulators were compared to prove that vector method is effective and more accurate.

Modeling of Anisotropic Fractal Surface

Zhou Chao, Huang Jianmeng, Gao Chenghui

2015, 26(8):  1019-1023,1061. 

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In order to model anisotropy surface geometry of components in computer, the algorithm of anisotropy fractal surface synthesis was studied, where any single or multi anisotropy direction fractal surface with specified fractal parameters could be synthesized based on the projection and rotation property of 2D discrete Fourier transform. And the relationship among fractal  parameters, power spectrum and surface geometry appearance was discussed. It is found that anisotropy fractal surfaces can be modeled precisely, intuitively and conveniently with respect to the power spectrum of surfaces.

Proportional Electromagnetic Valve Driven by Frequency-varying PWM

Kang Jian, Shang Shasha, Jiao Wenxue, Wang Xing, Pu Dingchao, Niu Zhen, Ye Qituan, Wang

2015, 26(8):  1024-1028. 

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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.

A Change Point Detection Method Based on Modified Hausdorff Distance in Nonparametric Profiles

Nie Bin, Sun Huidong, Li Pei, Du Wenchao

2015, 26(8):  1029-1034. 

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Change point identification in profile monitoring is an important research topic  in  statistical process control. Herein, the profile had nonparametric characteristics. The proposed method was based on Hausdorff distance,and could be used to measure difference between profiles. A modified Hausdorff distance algorithm was proposed to identify nonparametric profile change point. The comparison results of simulation study show that when there exists local changes in nonparametric profile, the modified algorithem has advantages in locating change points and performance stability.

Intelligent Flexible Distributed Electric Vehicle Platform

Luo Jian, Luo Yugong, Zhang Shuwei, Li Keqiang

2015, 26(8):  1035-1039. 

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In order to improve the scalable performance and the level of integration of the existing intelligent electric vehicle platforms, this paper proposed the overall structure of an electric drive flexible vehicle platform. Because of the open structure and modular part configuration, it was easy to change system parameters, to add new components and to upgrade parts, so fast realization and verification was possible. Simulation and experiments show that, the platform can be configured into many types to fulfill related experiments.

An Algorithm for Tolerance Cutter-location Surface Generation of Measured Data Based on MLS Method

Li Xiangjia, Dai Ning, Liao Wenhe, Guo Baosu, Wang Yongbo

2015, 26(8):  1040-1047,1057. 

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Traditional offset method can not directly generate the cutter-location surface of measured data with defects. Thus, a tolerance  method of cutter-location surface generation was proposed based on MLS fitness. Firstly, the measured data were transformed to a swelling ball model by the length of ball-end cutter's radius. Secondly, according to the geometric principle of convex hull, outer envelope data of this swelling ball model were acquired. Finally, local MLS projection fitting method was used to eliminate possible defects, and generated the final cutter location mesh surface. It is shown that this algorithm is able to generate cutter-location surface of measured data even they have defects, and also is suitable for the practical engineering applications for its high efficiency and accuracy.

Framework of Complex Task Oriented Service Composition and Optimization in Cloud Manufacturing Systems

Liu Bo, Zhang Zili

2015, 26(8):  1048-1057. 

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To circumvent the problems of SCO in the typical scenarios of complex multi-task requests, severe QoS constraints on tasks, and services shortage relative to tasks in cloud manufacturing systems, a framework of global optimal strategy for complex task oriented services composition(GOS-CTOSC) was presented. In this framework, the principles of multi-task oriented holistic optimization and the ideas of composite services binding and sharing were proposed to eliminate the drawbacks of traditional SCO approaches. Based on the principle, the composition patterns of  “each composition for each task”, “multi-composition for each task” and  “multi-composition for multi-task”  were designed in the framework, and the related problem models were also formulated. The implementation and evaluation of the framework were conducted in a prototype system, by means of the hybrid-operator based matrix coded genetic algorithm. The experimental results indicate the presented framework is sound performance-wise.

Conceptual Design and Simulation of a Novel Speed Self-stabilizing Mechanism

Su Rui, Rui Xiaoming, Wu Xin

2015, 26(8):  1058-1061. 

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A speed stabilizing mechanism was introduced for outputing constant frequency current of wind turbine. The traditional feedback adjusting speed stabilizing mechanism and the novel speed self-stabilizing mechanism were contrasted and analyzed from the angle of the kinematics principle. The Simulink models of wind power system with different speed stabilizing mechanisms were built. The time varing speed of wind rotor simulated by FAST software served as the inputs of the model. Two kinds of speed stabilizing mechanisms worked under the same input conditions. The simulation results show that the quality of steady speed from novel speed self-stabilizing mechanism is better than that from traditional feedback adjusting speed stabilizing mechanism.

BSS Method of Gearbox Multi-fault Based on LCD

Yang Yu, Li Yongguo, He Zhiyi, Cheng Junsheng

2015, 26(8):  1062-1066. 

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BSS is an effective multi-fault diagnosis method, and LCD is an effective tool of analyzing and processing non-stationary signals. Combining the advantages of LCD and BSS, a BSS of gearbox multi-fault was proposed based on LCD. The source signals were  decomposed by LCD to constitute new multidimensional signals, then estimating blind source number by Bayesian information criterion(BIC) to restructure the multidimensional signals, finally, using joint approximate diagonalization to separate the blind source signals. Simulation and experiments show that the method can effectively separate the blind source of the gearbox multi-faults, and provide a new method for fault diagnosis of the gearbox.

Temperature Characteristics of PP of Axial Piston Pump

Yin Yaobao, Chen Hao, Li Jing

2015, 26(8):  1073-1077,1084. 

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A  mathematical model was built,and the flow status of film in piston pair was researched, based on an axial piston pump of Rexroth Company, Germany. It focused on affects to film temperature against different pressure, speed, entrance oil  temperature and wall temperature and combined with software control variably. It shows that the film temperature is in direct ratio to the pressure, speed, and while in inverse ratio to entrance oil temperature and wall temperature. The peak of oil temperature maybe exists in piston pair.

Thermal Error Characteristics Analysis of CNC Machine Tools

Miao Enming, Gao Zenghan, Dang Lianchun, Miao Jichao

2015, 26(8):  1078-1084. 

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Thermal errors of CNC machines were different under actual cutting and spindle idling. The methods of fuzzy clustering and F statistics were used to classify temperature variables,as well as to confirm the best threshold. Then the temperature sensitive points were selected according to grey correlation among temperature variables and thermal errors. At last, a model among  temperature sensitive points and thermal errors was built. The results show that temperature sensitive points will be changed under two situations, the model under different situations can not be used mutually-interchanging. The model under actual cutting should be used.

Research on Influences of Nonlinear Hydraulic Spring Force on Nonlinear Dynamic Behaviors of Electro-hydraulic Servo System

Zhu Yong, Jiang Wanlu, Liu Siyuan, Zheng Zhi,

2015, 26(8):  1085-1091,1104. 

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With electro-hydraulic servo system as the research object, the influences of nonlinear HSF on system dynamic characteristics were explored. Based on the principles of the nonlinear dynamics, a dynamical model of the system was established. Then, a conclusion is indicated: the effects of nonlinear HSF can be described by Duffing equation. The bifurcation phenomenon and typical nonlinear dynamical behaviors which implied within system were revealed through numerical analyses. The measured dynamic data were thoroughly analyzed. The “jump phenomenon” caused by soft or hard spring property was revealed. The results indicate that the nonlinear effects of HSF can cause nonlinear vibration, and it should be taken into account in system modeling and dynamic characteristics research.

Research on Reliability of Multi-state System Based on Interval Triangular Fuzzy Bayesian Networks

Zhang Ruijun, Zhang Lulu, Wang Xiaowei, Wang Nannan

2015, 26(8):  1092-1097. 

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In order to overcome the shortages of dealing with fuzzy information in traditional system  reliability analysis methods, this paper proposed a new method of reliability analysis method based on interval triangular fuzzy multi-state Bayesian network. An  interval triangular fuzzy subset was built to describe fault rate of root nodes. A model of the interval triangular fuzzy multi-states Bayesian networks was built based on the interval triangular fuzzy subset. The calculation methods of leaf node fault probability were proposed, and the deblured posterior probability was researched by the reliability analysis algorithms of interval triangular fuzzy multi-state Bayesian network. At last, the method was applied in the reliability analysis of tower crane overturning accident, which shows that the proposed method is feasibility.

SCE Modeling and Influencing Trend Analysis of Cutting Parameters

Zhang Hongchao, Kong Lulu, Li Tao, Chen Junchao

2015, 26(8):  1098-1104. 

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This paper analyzed the energy consumption phenomenon with respect to the material removal mechanism and gave an empirical formula. An index formula was worked out based on the experimental data related to the facing processes performed on a turning machine. The influencing trends of cutting speed, feed rate and cutting depth on SCE were analyzed, which provides the basic indication for energy-saving machining parameters' selection and low-carbon manufacturing assessment inventory requirements.

Pole Placement for Single Input Linear Time-invariant Discrete Systems by Acceleration Feedback

Liang Qing, Wang Zhen, Pan Jinwen, Peng Cheng

2015, 26(8):  1105-1111. 

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The feasibility of pole placement by acceleration signal for single input time-invariant linear discrete systems was discussed. Firstly, the theorems and algorithms of pole placement by state-difference were provided. Secondly, the effectiveness of the proposed method was validated by three simulation examples. Finally, an experimental platform was setup to validate the feasibility of the proposed method.

Robustness Design for Crimping of Large Diameter Straight Welded Pipe

Fan Lifeng, Gao Ying, Yun Jianbin, Bai Yujie

2015, 26(8):  1112-1116. 

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To improve crimping forming quality, this paper investigated crimping which was simulated using the FE code ABAQUS and the FE model was validated experimentally. Based on this analysis, robustness design method based on stochastic model was used to obtain optimization design scheme, which considered the effects of uncertain factors such as material performance parameters on the forming quality. The research results show that the optimization design scheme can improve the product performance, and increase the reliability from 4.2% to 97.7% and ensure the product quality. Thus, the results herein provide an effective approach for crimping parameter design.

Three-dimensional FEA of Manufacturing Process of Small-diameter Split Sleeve by Two-axle Bending

Gong Jingping, Li Xiangfeng, Zuo Dunwen, Kang Xiaojun, Qiu Jiabin

2015, 26(8):  1117-1124. 

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Based on the two-axle bending technique, a three-dimensional FEA was developed for the manufacturing process of small-diameter split sleeve of 0Cr15Ni7Mo2Al, in order to guide the actual manufacture of the small-diameter split sleeve. The model  was verified with two-axle bending experiments. Stress strain distribution, deformation of rigid axle, the relationship among rigid axle diameter, workpiece size and curvature radius were analyzed. The simulation results show that workpiece deforms more equally with the increases of feed. The force of rigid axle becomes smaller with the increase of diameter, while deformation of rigid axle becomes lager with the decrease of diameter. The curvature radius increases with the increase of rigid axle diameter. The curvature radius increases with larger width and thickness of workpiece.

Optimal Allocation of Redundant Actuator and Active Safety Control for Wheel-motored Electric Vehicle

Ding Xiying, Wang Yanan, Li Lin, Zhang Zeyu, Wang Chunqiang

2015, 26(8):  1124-1128. 

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Contraposing the new chassis structure, a hierarchical vehicle stability control strategy was used and combined the gesture tracking and chassis manipulated variable optimized allocation. The high level of the control strategy conquered the system nonlinear by adopting precise linearization control strategy, which proposed the required torque for the improved steer structure. Quadratic programming was used in the low level, which aimed at optimizing the redundant actuator,minimizing the output of the tracking errors and tire force posture parameters, and decreasing energy consumption of the vehicle. The simulation results indicate that the proposed method can enhance the vehicle handling stability,the control efficiency is also improved.

Multi-objective Optimization of Powertrain Mount System Concurrently Considering Energy Decoupling and Vehicle Vibration

Chen Jian, Shi Weiyi, Jiang Fengxin, Zeng Weijun, Shen Zhongliang, Wang Yifeng

2015, 26(8):  1129-1135. 

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Simplified vehicle vibration TPA model was established based on the actual transfer path test datum. On the basis of that, multi-objective optimization model of powertrain mount system was established based on GPSO algorithm with considering energy decoupling and vehicle vibration, mounting stiffness parameters were taken as design variables. Taking a truck for example, a multi-objective optimization solution was conducted. The test and optimization results show that the optimization method can get better energy decoupling and lower vehicle vibration, while achieving the optimal matching of energy decoupling and cars and low vibration.