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Table of Content

    10 August 2016, Volume 27 Issue 15
    Design and Analysis of Active Heave Compensation System for Offshore Cranes
    Wu Jinbo, Song Yuchen
    2016, 27(15):  1989-1996. 
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    To compensate the heave motion of the ship's crane during marine operation, the crane's hydraulic driving system was constructed based on the secondary regulated hydrostatic drive technology. Firstly, a full mathematic model of the heave compensation system was presented. A triple closed-loop control structure was proposed, which included the position closed-loop of the stroke cylinder fixed in the secondary unit, the speed closed-loop of the secondary regulated hydraulic motor and the position closed-loop of the secondary regulated hydraulic motor. Afterwards, a simple design method was proposed to ascertain the three controllers' parameters. In order to obtain the position of the crane's cargo, an observer was designed to estimate this state by using the wire rope tension. Lastly, a design example for the active heave compensation was provided. The dynamic characteristics of the heave compensation system were analyzed from the frequency domain standpoint by numerical simulations, which helpes lay a foundation for control strategy research.
    Free Vibration Analysis of Driving Mechanisms of a Rotary Inchworm Piezoelectric Motor
    Xing Jichun, Zhang Nan, Li Chong
    2016, 27(15):  1996-2002. 
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    A novel rotary inchworm piezoelectric  motor was proposed herein. Considering the driving mechanism of the rotary inchworm piezoelectric motor was a continuous system, the dynamics model of the driving system was presented. The natural frequencies and mode function of the drive mechanism of a prototype were solved by using the dynamics model. The influences of system parameters on the natural frequency of the driving mechanism were analyzed. All the conclusions lay a theoretical foundation for the design of the rotary inchworm piezoelectric motors.
    Tooth Contact Analysis of Profile-shifted Non-orthogonal Face Gear Drive with Longitudinal Modified Pinion
    Zhou Zhenyu, Tang Jinyuan, Ding Han
    2016, 27(15):  2003-2009. 
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    The coordinate systems for the processing and meshing of the non-orthogonal face gear drive with longitudinal modified pinion use were established. The tooth surface equations of the profile-shifted pinion and the profile-shifted non-orthogonal face gear were deduced; simultaneously the numerical tooth surface of the face gear was calculated. The impacts of profile-shifting on tooth width of the non-orthogonal face gear were analyzed. A kind of modification mode of the face gear drive is studied,where the pinion is longitudinal modified based on considering profile-shifting, while the tooth surface of the face gear is not modified. The tooth contact analysis considering the misalignment errors is conducted for the ordinary non-orthogonal face gear drive, the profile-shifted non-orthogonal face gear drive and the profile-shifted non-orthogonal face gear drive with longitudinal modified pinion respectively. The results show that: the minimum inner radius of the non-orthogonal face gear reduces, the maximum outer radius of the non-orthogonal face gear reduces, and the limit tooth width decreases along with the increasing of the profile-shifting coefficient; profile-shifting has no impact on the contact law of the non-orthogonal face gear drive; a longitudinal modified pinion can reduce the sensitivity of contact path to the misalignment errors and will induce a type of linear transmission errors with low amplitude.
    Control Strategy of Multipoint Jacking System Based on Generalized Predictive Adjacent Coupling Theory
    Huang Kang, Gong Miao, Zhong Huayong, Wang Kailai
    2016, 27(15):  2009-2014. 
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    A control strategy combined generalized predictive control and adjacent coupling synchronization control was proposed for synchronization control of multipoint jacking system. A CARIMA model of multi cylinder electro-hydraulic servo system was established based on multivariable generalized predictive theory, then combining adjacent coupling synchronization control theory, a synchronization error observer was constructed for forecasting synchronization errors. In order to guarantee that the tracking errors and synchronization errors converged to zero asymptomatically in the global range, both of the errors and their corresponding differential components were embedded into the performance index. Experimental results show that this strategy has better performance of tracking and synchronization comparing to master-slave PID control strategy.
    Damping Coefficient Identification and Analysis for Squeeze Film Dampers
    Zhou Hailun, Feng Guoquan, Zhang Ming, Ai Yanting
    2016, 27(15):  2015-2020. 
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    In order to identify damping coefficients of SFD, the experimental tests were researched. Firstly, the bidirection excitation rig was excited by signal generator and power amplifier. Then the excitation and response data were obtained by impedance head. Lastly, damping coefficients of SFD were obtained by the least squares fit based on the principles of mechanical impedance. The influence of SFD parameters on damping coefficients was researched by changing oil width and clearance. The experimental tests show that the oil damping presents a trend of nonlinear increase with the increase of oil width. Oil damping can be increased by increasing the oil width, then the damping performance of the damper is improved. With the increase of the oil film gap, oil damping presents a trend of nonlinear decrease, and damping performance is declined.
    TS Fuzzy Trajectory Tracking and Doubleflexible Parallel Control of Flexiblelink Flexiblejoint Space Manipulator
    Hong Zhaobin, Chen Li, Li Wenwang
    2016, 27(15):  2020-2026. 
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    Aimed at the problems of flexiblelink flexiblejoint space manipulator with parameter uncertainties and external disturbances to track the desired motion, the TS fuzzy control and doubleflexible vibration parallel control were proposed. Firstly, a joint flexibility compensation controller was introduced to improve the equivalent stiffness of each joint. Secondly, the error dynamic equations were obtained based on feedback linearization in the trajectory tracking procedure, and control parameters of fuzzy control was selected by Lyapunov stability theory.Subsequently, the fuzzy sliding mode control was improved with simple TS fuzzy rules. The great advantage of proposed control is free of undesirable chattering phenomenon in sliding mode control and light burden of computations. Then, the doubleflexible parallel control was presented to suppress the vibration of flexible links. Finally, the simulation results on a space manipulator demonstrate the validity of the proposed control scheme.
    Multifloor Reconfigurable Facility Layout Method Based on Improved Plant Growth Simulation Algorithm
    Ding Xianghai
    2016, 27(15):  2027-2034. 
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    A method of multifloor reconfigurable facility layout was presented based on improved plant growth simulation algorithm. According to the features of multifloor reconfigurable facility layout problem, spacefilling curves were used to describe the facility locations, making it possible to exchange any two facilities. Flexible area requirements, shape constraints and elevator utilization were used to keep the layout solution's feasibility. Considering the material handle costs and facility reconfigurable costs together, a performance evaluation model was constructed. Based on the improved plant growth simulation algorithm, the performance improvement algorithm was developed. At last, two examples were presented to show the accuracy and generalization of this method.
    Gyratory Crusher Productivity Analysis Based on Kinematic Characteristics of Materials
    Li Qiang, Gong Yadong, Song Weigang
    2016, 27(15):  2034-2039. 
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    For investigating the bulk material breakage performance of gyratory crusher under the low speed of mantle and improving the structure of crushing chamber, combining with the kinematic and dynamic characteristics of materials,a calculation method of productivity was proposed. On the basis of Layered breakage theory and the structure of crushing chamber, the bulk material motion forms of discharge and compressive half cycle were researched and the trajectories were draw. Productivity was solved based on the materials velocity of upward and downward in the choke layer. Numerical results of PXF6089 gyratory crusher were presented. The data of actual production and discrete element  method were adopted to verify the results accuracy. Simulation results and physical experimental  results show the calculation method is accurate.
    ARTIS Tool Monitoring System Using in Milling of Aerospace Structural Components
    Zhu Shaowei, Li Weidong, Tang Limin, Du Li
    2016, 27(15):  2040-2043. 
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    In order to figure out the problems when ARTIS was used in milling of aerospace structure components, the variation rules of monitoring signals relative to representative part features were analyzed. Consequently, a few of application solutions was proposed to reduce the false alarms. Application cases show that the false alarm is reduced obviously, and the monitoring accuracy is improved.
    Researches and Applications of Mesh Transition Algorithm for Full-coverage Crown Dentures
    Yan Guodong, Jia Binghui, Lin Xiaohua, Jia Wenhua, Ke Guangyun
    2016, 27(15):  2044-2047. 
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    For the transition fusion problem of the inner and outer crown in the digital design of full-coverage crown dentures, a new mesh transition algorithm was proposed. First, mesh boundaries of the inner and outer crowns were extracted to form closed holes by bridging. Then holes were filled by triangular facets according to the definition of inserting rules, and the initial transition meshes were structured. Finally, the initial transition meshes were projected onto the implicit surface obtained by the boundary interpolation, and new transition meshes were structured by projection points, which fused the outer and inner crown topology to form a complete full-coverage crown denture restoration. Meshes obtained by mesh transition algorithm distributed equally, and the quality of triangular facets is good. What's more, transition boundary is smooth, and it has good continuity.
    Composite Hierarchical Fuzzy Entropy and Its Applications to Rolling Bearing Fault Diagnosis
    Zheng Jinde, Pan Haiyang, Qi Xiaoli, Pan Ziwei
    2016, 27(15):  2048-2055. 
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    Since the similarity measure in sample entropy and MSE changed abruptly and MSE might not capture high-frequency informations, a new method for measuring complexity of time series called CHFE was proposed. Meanwhile, in order to extract the early fault features of rolling bearings, a new fault diagnosis method was proposed  based on CHFE, Laplace score for feature selection and support vector machine(SVM). First, the CHFEs were extracted from vibration signals of rolling bearing and then the Laplacian score was used to reduce dimension of features. Next, the SVM based multi-fault classifier was founded to fulfill the fault diagnosis. Finally, the proposed method was applied to experimental data analysis and the results indicate the validity.
    Clustering Optimization Fusion Method for Fault Diagnosis and Its Applications
    Jiang Lingli, Mo Zhijun, Chen Anhua, Li Xuejun
    2016, 27(15):  2055-2059. 
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    Single community diagnosis clustering methods were difficult to identify different fault states, in order to improve diagnostic accuracy, a fusion clustering method was proposed herein based on genetic optimization algorithm. Three clustering methods, the community clustering, the Kmeans clustering and the particle swarm clustering, were used to identify the fault states respectively. The diagnostic accuracies were used to construct an initial weight matrix. The genetic optimization algorithm was used to optimize the weight matrix. The examples of bearing fault diagnosis show that the clustering optimization fusion method may improve diagnostic accuracy.
    Pumpcylinder Composite Structure New Dynamic Flowmeter
    Liu Tao, Song Tao, Yao Hui,
    2016, 27(15):  2060-2063,2068. 
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    Aiming at the problems of accurate measurement of the complex type of high frequency dynamic flow, a new type of dynamic and static flow meter was designed based on the composite structure of pump and cylinder. The noload cylinder portion of flow meter had good dynamic performance, which was responsible for the measurements of high frequency flow components. The metering pump portion might measure continuously and reciprocating, which was responsible for the measurements of lowfrequency and steady components. The metering pump was driven by a servo motor, and the angular velocity of metering pump was controlled to lead the equilibrium position of noload cylinder to zero. Through the measurements of the velocities of noload cylinder and the angular velocities of the pump, the complex dynamic flow might be obtained. Based on threedimensional design of flowmeter, utilizing AMESim to build the flowmeter physical model, using MATLAB to complete the flowmeter control system modular design, the cosimulation of pumpcylinder composite structure flowmeter was done to verify the dynamic performance of composite structure dynamic flowmeter and the rationality of design parameters.
    Optimum Design of Accelerated Life Test Plan on non-rectangle Test Region Based on Uniform Design Theory
    Chen Wenhua, Zhu Zhipeng, Gao Liang, Pan Jun, Kong Xiangze
    2016, 27(15):  2064-2068. 
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    Aiming at the problems of hardly finding out the points of the maximum probability of failure on the complicated boundary curves when designed the optimal multiple stress accelerated life test plan on the non-rectangle test region based on Escobar-Meeker method, minimum variance of product life estimated value at normal working stresses was taken as design object for constant stress accelerated life test method. After selecting two stress level points as the highest level point and the lowest level point on the non-rectangle test region , the highest stress level , the lowest stress level of each accelerated factor and allocation proportion of test samples were adopted as design variables; the optimum design method of multiple stress accelerated life test on the non-rectangle test region was built based on uniform design theory. The computer simulation results show that the optimized test plan has the same estimation precision of test data compared to the optimized test plan based on the Escobar-Meeker method. The research fruits  provide a simple method for the test plan design of multiple stress accelerated life test on the non-rectangle test region.
    Selflubricating Ceramic Cutting Tool with Solid Lubricantbased and a Doublesitu Reaction Mechanism
    Liu Jingwen, Zhou Houming, Zhou Wen, Deng Jianxin, Zhang Gaofeng, Zhou Youhang
    2016, 27(15):  2069-2074. 
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    A selflubricating ceramic cutting tool was produced by the hot pressing vacuum sintering process, with the substrate of Al2O3/TiB2 and the addition of CaF2. Meanwhile the dry cutting tests were carried out. In the process of friction and wear test, there were four Al2O3/TiB2/CaF2(ABF) materials with different contents of CaF2. The results show that the friction coefficient of the material decreases with the increase of its contents of CaF2.The formation of CaF2 in the wear layer of a solid lubricating film during the antifriction lubricant film played a role, in the cutting tests which were carried out with respect to 45 steel at the speed of 120 m/min, the average friction coefficient of the ABF tools is much lower than that of the normal ceramic knives tool (AG2). And the main reason was the lubricating film which generated by the solid lubricant CaF2 and the situ reaction of TiB2,when the ABF selflubricating ceramic tool was cutting under the high speed. Meanwhile, with the increase of temperature and the cutting speed, its lubricating effect is improved significantly.
    Imaging Method of Monocrystalline Silicon Internal Defects Based on SAFT Time-domain Detection
    Wu Wei, Qiu Zongming, Huang Qiuhong
    2016, 27(15):  2075-2079,2084. 
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    A direct time-domain reconstruction and sizing method of SAFT was developed to improve the spatial resolution and sizing accuracy of monocrystalline silicon internal defects. The basic idea of the reconstruction algorithm was to coherently superimpose multiple A-scan measurements, incorporating the phase information of the sampling points. The algorithm involved data mapping and in-phase summation according to time-of-flight (TOF). A sizing method was proposed to characterize the flaw boundary based on the concept of 6 dB-drop. The extents, orientation and the shape of the flaw might then be inferred to provide more informations for monocrystalline silicon slicing process technology. The developed method was used to process the experimental data to characterize the flaws. Using the developed method, the improvement of spatial resolution was observed. Results indicate that two closely spaced 0.8mm-diameter holes are clearly identified, and the quantification of size and orientation of the natural flaw are very close to the actual measurements after cutting the testing piece apart.
    Interfacial Microstructure of Diamond Vacuum Brazing with CuSnNiCr
    Lu Jinbin, He Yaxun, Zhang Wangxi, Mu Yunchao, Ding Wenfeng, Zhong Sujuan, Ma Jia
    2016, 27(15):  2080-2084. 
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    In order to reduce the heat damage of diamond and manufacturing cost, using CuSnNiCr metal powder as filler and the experiments of brazing diamond abrasive grain were carried out. SEM, EDS and XRD were used to analyze the microstructure of diamond and brazing filler. The results show that the active component of the brazing diamond is Cu75Sn15Ni5Cr5, the melting point of the brazing filler is suitable for brazing diamond, and it can realize the chemical metallurgical bonding with diamond. The morphology of diamond is complete, the surface is smooth, and the surface of the diamond is as (Cr,Fe)7C3. The brazing filler solidification process of crystallized αCu dendrite, peritectic transformation and eutectoid transformation, the formation of dendrite, Cu5.6Sn, αCu and eutectoid αCu, the microhardness of the brazing filler is about 200~250HV0.2.
    Numerical Simulation and Experimental Verification of Asymmetrical Three-roll Bending Process
    Wang Yan, Hu Jiefei, Xu Guanghui, Li Shusheng, Xiong Wei
    2016, 27(15):  2085-2090. 
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    The stress field of deformation zone, the stain field of upper plate surface and the changes of roll bending forces were analyzed during the asymmetrical and symmetrical roll bending process by the finite element(FE) simulation method. The simulation results show that the bending force during the asymmetrical roll bending process is larger than that during symmetrical roll bending under the same feed distance of the side roll. Compared to the asymmetrical roll bending process, the longitudinal and radial stress in deformation zone in the symmetrical roll bending process are smaller. The forming accuracy of the asymmetrical roll bending process of the pre-bending section  is higher than that of symmetrical roll bending process.The experimental verification of a typical plates for the asymmetrical roll bending process was conducted, the result show that the forming error of FEA model is 6.8%.The FEA model has a higher forming accuracy.
    Gas-liquid Two-phase Flow Numerical Simulation of a Hydro-pneumatic Suspension by VOF Model and Dynamic Mesh Method
    Zhang Sha, Gu Zhengqi, Zhao Jingkai, Xu Ya, Wu Wenguang
    2016, 27(15):  2091-2099,2016. 
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    Considering that the hydro-pneumatic suspension of a large-scale mining dump truck was a type of oil and gas contact suspension, the multiphase flow numerical simulation method was considered to be used to analysis the nonlinear characteristics. At first, a gas-liquid two-phase flow model was set up in Fluent software by VOF  method, on the basis of discussing the applicability of existing multiphase flows modeling methods and the applicability of turbulence model. During the simulation, VOF model was able to track and locate the oil-gas interface and transfer the pressures between them. Dynamic grid technique was introduced and the movement of the two-phase flow model boundary was defined by UDF technique. In order to obtain the velocity and pressure contours of the suspension in different times, the time-dependent numerical simulation of the tension and compression processes of the hydro-pneumatic suspension was conducted, combining the VOF model and dynamic mesh method. The pressure changes in the air chamber and the pressure differences in the oil chamber due to the valve system structure was extracted, and then the stiffness and damping characteristics were calculated. Finally, the two-phase flow simulation results was validated with the help of a vehicle field measurements.
    Evaluation Method of Handling Force Feedback Comfort of Vehicle Gear Lever
    Liu Mingzhou, Zhang Miao, Hu Jing, Liu Zhengqiong, Chen Ziang
    2016, 27(15):  2100-2106. 
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    A method for evaluating handling comfort of vehicle gear laver was proposed based on its force feedback characteristics. The method combined the objective test with the subjective evaluation, to compensate for the inadequacy of subjective evaluation only. The variation of handling force feedback with the displacement of the gear lever and the driver's individual differences were analyzed. The relative force feedback maxima and relative handling stiffness were extracted as objective indicators for the processes of gear selection, in-gear and out-of-gear. In addition, back propagation (BP) neural network was improved by particle swarm optimization (PSO), thereby an evaluation model was established, which described the mapping relationships between objective indicators and subjective scores. Finally, the model was trained and tested by 48 groups of sample data obtained from the handling experiments, which took the manual transmission used widely in normal car for examples. The results show that the evaluation with proposed  method is accurate and stable, so that it can provide guidance for optimization design of vehicle transmissions.
    Hanger Point Location Optimization to Improve Automobile Exhaust System
    Huang Zehao, Zheng Fengyun, Jiang Guangzhi, Yuan Guangliang
    2016, 27(15):  2107-2111. 
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    In order to get a better location for the hanger of a exhaust system, this paper was focused on numerical analysis and theoretical research on the simplified model. Firstly, the hanger position was analyzed theoretically and a finite element model was established based on a passenger car. Secondly, the hanger position was determined with the methods of average driver DOF and improved method. Finally, the conclusion was obtained through force response of the two methods'results. It takes less time to calculate and establish a model with improved method, which is proved to be more efficient. Moreover, the location determined by improved method is more accurate, which has a less force response, less shock and less structural noise.
    Time Delay Compensation Control of Semi-active Suspension with Vehicle Electro-hydrostatic Actuator
    Kou Farong, Fan Yangqiang, Zhang Chuanwei, Du Jiafeng, Wang Zhe
    2016, 27(15):  2111-2117. 
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    To improve the ride comfort and stability of vehicles,a kind of the semi-active suspension with EHA was designed and the mechanical property tests of the electro-hydrostatic actuator were completed. The bond graph models of the time delay fuzzy control for EHA semi-active suspension were established. The critical time delay of the EHA semi-active suspension was calculated.The time delay impacts on the amplitude-frequency characteristics and vibration isolation properties were analyzed. The time delay fuzzy Smith predictive compensation controller was designed. The simulation analyses of the time delay compensation fuzzy control for the EHA semi-active suspension were done. The results show that the EHA semi-active suspension has good damping controllability. However, with the increase of time delay, the “jump vibration” phenomenon happens to the suspension system. Under the time delay compensation fuzzy control of the EHA semi-active suspension, the sprung mass acceleration drops by about 30% and the tire dynamic load drops by about 20%.
    Advances in Researches of Dynamics Problems for Free-floating Manipulator
    Gu Yongxia, Zhang Yuling, Zhao Jieliang, Yan Shaoze
    2016, 27(15):  2118-2129. 
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    The base of space manipulator kept in a free-floating state, which caused the kinematics and dynamics coupling between the base and manipulator and made that it was more complicated than the ground manipulator for the analyses of kinematics and dynamics as well as control, and it was a difficult and hot spot to establish accurate dynamics model and control strategies for space manipulator. The dynamics modeling methods as well as fine dynamics modeling were reviewed in detail herein, and the path planning methods such as attitude adjustment, nonholonomic path planning, singularities avoidance were summarized. Then the impact dynamics modeling as well as control in capturing a target for space manipulator were summarized. Based on the studies mentioned above, the problems of present dynamics modeling were pointed out, and some topics to be further studied were predicted.