Table of Content

25 March 2016, Volume 27 Issue 06

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Internal Force Analysis  and Coordination  of  a 5-UPS/PRPU Redundantly Actuated Parallel Mechanism

Zhou Xin, Xu Yundou, , Yao Jiantao, Zheng Kuijing, Zhao Yongsheng,

2016, 27(06):  711-717. 

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By  combining the overall Jacobin  matrix and pseudo-inverse matrix method, the internal forces of each driving limb of a 5-UPS/PRPU redundantly actuated parallel mechanism were derived,and a novel internal force  coordination method was presented.By using compatibility equation of deformation, the pseudo-inverse of the overall  Jacobian of the mechanism could be obtained.The internal forces  of the 5-UPS/PRPU parallel mechanism were solved as well,which was  verified by finite element method.To investigate the influences of stiffness of the redundant actuator on the internal forces of each driving limb,the 5-UPS/PRPU redundantly actuated parallel machine tool(PMT)  was  used to illustrate the method mentioned above,and a method to coordinate internal forces was proposed.The analyses show that the actuation wrench of the non-redundant limb and the constraint wrench of the redundant limb can be reduced by increasing the stiffness of the redundant actuator to some extent. The method may be used by mechanism designer and programmer to improve the systems precision and reduce the internal forces of the mechanisms.

Research  on High Pressure  Water Jet Cleaning Technology with Underwater Gas Injection System

Jin Chengzhu, Miao Yao, Pan Huachen

2016, 27(06):  717-720. 

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A  high pressure water jet cleaning technology with  underwater gas injection system was proposed herein. A testing device was designed based on this technology, and could inhibite internal pressure fluctuation effectively under the mass flow water jet experimental conditions by control of water surface elevations and pressures.The influences of gas-liquid ratio on flow field under 10 meters of water depth were analyzed in order to effectively expand the distance of underwater high pressure water jet . The analysis results show that the jet velocity can be increased by increasing gas-liquid ratio of external jet flow and provide theoretical basis for underwater cleaning.

Molecular Dynamics Simulation of Single Crystal Copper Material Surface Cutting Properties in Nano-scale

Li Yong, Yang Xiaojing

2016, 27(06):  721-726. 

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The surface cutting properties of single crystal copper material were researched by using molecular dynamics simulation. Through molecular dynamics modeling, calculation and analysis, the influences of different cutting speeds or  cutting thicknesses on single crystal copper surface nano-cutting process microscopic atomic states and the change rule of contact area cutting force were studied.The results show that the accumulated volume of chips increases with the cutting speed increases in nano-cutting process of single crystal copper surface,at the same time the atoms in the chip stack are tighter and the distribution of dislocation defects is wider.The accumulated volume of chips in front of tool and the dislocation defects increase with the cutting thickness increases in a same cutting speed. In different cutting speeds or cutting thicknesses,the cutting force will rise at first, and float around a stable value after reaching a steady stage. During initial stage of cutting, the higher the cutting speed or cutting thickness, the larger rise range of cutting force. After reaching the steady stage of cutting, the higher the cutting speed or cutting thickness, the larger cutting force.

Research  on  Single-wheel Self-balancing  Robot Based on Horizontal Gyro  Structure

Li Zhihong, Chen Run'en, Cheng Xiaodong, Wang Weichao

2016, 27(06):  726-731. 

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A new type of single-wheel robot was presented herein.This single-wheel  self-balancing robot had a single horizontal gyro structure.First,using the inertia and stability of gyro to turn a two dimensional unstable inverted pendulum system into a two dimensional quasi-stable inverted pendulum system.And then according to the  principle of precession, using the method of rotating counterweight on the system to recover the unbalanced attitude,thus this single-wheel robot had a strong ability to resist disturbances.The research focused on attitude unbalance and recovery of the single-wheel robot. Test prototype of single-wheel robot realized attitude stable on fixed point, unbalanced attitude recovering and walking, steering.

Motion Characteristic Analysis  of Bearings in Hooke Joint Based on Perspective Geometry

Chen Ke, Yin Lei, Guo Wei, Zhang Jianzhong,

2016, 27(06):  732-736. 

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The formulas of bearing rotation angle in Hooke's joint were established based on  the coordinate transformation  method and space perspective geometry according to the analysis of kinetics' behaviors of the Hooke's  joint. A numerical method  for calculating bearing  rotation speed  in  Hooke's  joint was set up. By adaption of above mentioned formulas and numerical method, the relations  among  instantaneous rotation angle, rotational speed and true joint angle were  analyzed, and the  results were validated by kinematics simulation. The results indicate that the bearing rotation speed in driving fork is higher than that in driven fork and the bearing rotation speed wave in  driving fork is higher than that  in  driven fork. The conclusions obtained give basis for analysis of friction, abrasion and lubrication state of bearings in Hooke's joint.

Shape Optimal Design of Leaf End for Multileaf Grating

Zhou Dong, Zhang Hui, Ye Peiqing

2016, 27(06):  737-742. 

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In order to improve dose delivery accuracy and reduce the dose error caused by penumbra, an analytical penumbra model was presented based on tangent secant theory. With penumbra width mean across radiation field set as objective function, leaf end shape optimization was proposed, which was applied for leaves in the shape of circular arc with center offset from the axis of leaf mean height. Furthermore, shape optimal design of leaf ends for on-axis and off-axis leaves was introduced. Results show that penumbra width mean is reduced by 1.6% for the optimized leaf end, compared with the method of maximum arc intersection radius.

Configuration  of Aerial Self-lubricating  Spherical Plain Bearing Testers

Li Wei, Hu Zhanqi, Yang Yulin, Fan Bingli, Qi Xiaowen

2016, 27(06):  742-747. 

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Based  on  oscillation  and  wear  forms of the spherical plain bearings,the motion-characteristic matrices of spherical plain bearings were built.On the basis of moving and loading features of the spherical plain bearings, 49 theoretical configurations of spherical plain bearing tester were obtained. Meanwhile,the existing life testers were divided into four categories, and the typical testers of 4 categories were analyzed.Finally,according to actual working conditions,two improvable configurations of spherical plain bearing testers were indicated,and then the design schemes of two life testers were presented.

Flour Field  Simulation of  Small  Holes  Machined by the  RUECM

Liu Zexiang, Kang Min, Li Shusheng

2016, 27(06):  748-753. 

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In  order to solve the difficulties to update the electrolyte and discharge the products in  the electrochemical machining(ECM)  for deep-small holes,  the internal rotary ultrasonic electrolytic composite machining device  was  constructed,and  the comparative experiments of  ECM,rotary electrochemical machining(RECM) and RUECM were carried out.The results show that the roundness of holes is improved by the rotation of cathode and the average current  is the largest in the RUECM,thus the diameter and the depth of the holes machined by  RUECM are the  largest, which indicates that the material removal rate (MRR) is  the greatest, too. Based on those, the effects of the rotation and vibration of cathode on the flow field and electric field  were  analyzed by ANSYS CFX with the three-dimensional two-phase flow cavitation model. The simulation results show that when cathode rotates,the air bubbles are gathered on the cathode surfaced,which is not conducive to the discharge of air bubbles; when   cathode vibrates,the motion  of electrolyte is accelerated,which is conducive to the discharge of air bubbles, therefore,it has the greatest MRR in RUECM,which provides a  basis for future researches.

Multi-objective  Optimization  for  Turbocharger  Housing  Considering Thermo-fluid-solid Interaction

Li Fazong, Tong Shuiguang, Yuan Minghong

2016, 27(06):  754-760,766. 

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A  thermo-fluid-solid  interaction  method of  turbocharger housing was  proposed  and  a  finite element model was established.The thermal structure of turbocharger housing was analyzed.The distribution   of  thermo plasticity strain and the location of thermal structure destruction of turbine housing were found by thermo-fluid-solid  interaction  analyses.Analysis results were  compared  with the thermal  cycling  test results of  the turbine housing and the correctness of the thermo-fluid-solid  interaction  model was proved.The thermo plasticity strain of three risk regions in turbine housing were selected as optimization objectives,a structure optimization approximation model was established by response surface method,  which took size parameters of dangerous parts as design variables and the thermo plasticity strain of turbine housing as optimization objectives.The optimal structural parameter combination of the turbine housing was obtained by multi-objective optimization method based on response surface method and genetic algorithm,and the optimization model was verified by thermo-fluid-solid  interaction experiments.The  results show that the thermo plasticity strains of three risk regions in turbine housing decrease from 3.3%,3.2%,2.6% to 0.66%,0.8%,1.03% respectively.The  optimization method  can improve thermal structure intensity,reduce  the risk of hot cracking formation and improve the stability and  reliability of heat structure of turbine housing.

Process Parameter  Optimization Based  on  PSO-BP Neural Network in Point Grinding Fluorophlogopite

Ma Lianjie, Chen Jie, Gong Yadong, Wang Jia

2016, 27(06):  761-766. 

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Through  a high speed point grinding experiment,the surface hardness and roughness of the finished surface was tested, and the variations of the surface hardness and roughness with the process parameters were analyzed.Single factor experimental values were predicted with PSO-BP.A series of one-dimensional models of  surface hardness and roughness process parameters of fluorophlogopite were built by least-squares fitting. Correlation coefficient test was used to verify the models' high reliability.Multivariate models about surface hardness and roughness process parameters were proposed by analyzing one-dimensional models.The multivariate numerical  models  were optimized according  to the results of orthogonal experiments and PSO and  were proved  to have high reliability by  experiment.A  dual objective optimization  of  two  multivariate models was carried out by PSO algorithm, and a set of reasonable process parameters was obtained.

Study on Sensorless Control Strategy of PMSM for Compressor at Full Speed Range

Deng Jianguo, Cai Yahui , Huang Shoudao, Li Yaxiong

2016, 27(06):  767-771,777. 

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A method applyed for compressor with PMSM sensorless and full speed range  operation  conditions  was presented. An I/F control strategy with speed open-loop and current closed-loop  was used at start-up and low speed stage of the motor.Sensorless control strategy which was based on an improved model reference adaptive system was used at middle or  high-speed stages,and realized no impact switch of  two control strategies. The analysis results of simulations and experiments prove the validity of this method.

Multi-software Co-simulation for a Large Robotic Automatic Stamping Production Line

Qiu Xuesong, Xiao Chao, Tan Houjin, Hou Yulei, Zhou Yulin

2016, 27(06):  772-777. 

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For the rapid design of large robotic automatic stamping production line, based on interface technology and multi-software co-simulation， a method was proposed to meet design requirements, such as kinematics, dynamics, stiffness and so on. By Dynaform software, sheet metal forming process was simulated, and dynamic load curve was captured and loaded into virtual prototype to approximate real load. Key components were changed into flexible bodies by ANSYS and were imported into ADAMS to replace corresponding rigid bodies and a rigid-flexible coupling virtual stamping production line was established. Processing vehicle side panels were taken as an example, and the mathematical models of kinematics and dynamics of main press in the stamping production line were established. The energy consumption index and safety- efficiency balance index were proposed to evaluate the comprehensive performance of the system. The rigid-flexible coupling virtual prototype simulation results were compared with theoretical calculations and multi-body virtual prototype simulation results. The analysis results show that rigid-flexible model can improve the simulation accuracy, may be closer to the real process and possess theoretical direction significance for overall design of stamping production line, the key parameter selection, on-site installation and commissioning.

An Adaptive Adjustment Method of Composition Exception for Manufacturing Cloud Service

Ma Wenlong, Zhao Yanwei, Wang Wanliang

2016, 27(06):  778-784. 

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In order to solve the problems of service composition exception in cloud manufacturing environment,an  adaptive adjustment method of  composition exception for manufacturing cloud service was presented herein.The service exception handling model was established to capture, classify and abstract the exception information. Based on this model, a series of adjustment strategies were proposed to handle corresponding exceptions.By  using exception evaluation mechanism and adaptive adjustment algorithm, the adaptation of service composition was realized.The experimental results show that the method can solve exception problems effectively and improve the flexibility of cloud service composition.

Review  on  Fund Management of Mechanical Engineering Discipline of  NSFC  in  2015

Lai Yinan, Song Jianli, He Baiyan, Liu lei

2016, 27(06):  785-790. 

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The applications, evaluations and funding of programs in the Division of Mechanical Engineering of NSFC in 2015 were reviewed herein.The research progresses of undertaking programs and the  achievements of finished programs in 2014 were summarized, problems should pay attention to in program implementation were indicated. The management measures on major project approving demonstration, academic exchange and cooperation, cultivating of young talents, construction of the innovation teams, and encouragement of innovations were introduced. The latest progresses and typical achievements obtained in the fields of mechanical engineering supported by NSFC in 2015 were reviewed, and the planned work and prospects in 2016 were also proposed.

Integrated Optimization Design of Cab Suspension and Suspension Parameters for Heavy Tractor

Zhao Linfeng, Hu Jinfang, Zhang Rongyun

2016, 27(06):  791-795,808. 

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In view of the automotive multivariate integration optimization problem of riding comfort and handling stability, taking the heavy tractor as a research object, the vehicle model with the cab suspension and air suspension was established. The tractor cab suspension and suspension parameters etc.11 parameters were chosen as variables to design experiments, then the mathematic model of multi-objective collaborative optimization was established. The six variables were identified as optimization parameters based on the ideal parameter modification method, by using the RSM fit four regression models which were weighted to get the optimal solution and the size of the weighting factors. Compared with the simulation results where only suspension parameters were completed optimization design, it is shown that the cab suspension and the suspension parameters integrated optimization are more ideal, ride comfort and handling stability are improved obviously.

Study on Single Cavitation Bubble Collapse Temperature in Ultrasonic Vibration Honing

Zhang Xiaoqiang, Zhu Xijing, Wang Jianqing

2016, 27(06):  796-800. 

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In order to investigate the cavitation impacts under ultrasonic vibration honing, the single-cavitation bubble thermodynamics equation was established based on ultrasonic cavitation dynamics and fundamental laws of thermodynamics. Numerical simulation was carried out, and the different influences were performed to the bubbles moving radius, when the honing parameters changed. The effects on the bubbles collapse temperature were analyzed indirectly. The results demonstrate that the change of parameters is non-significant to the bubbles collapse temperature, and it is about 300～1400K. The process was tried out on ultrasonic drilling machine, with aluminium foil as test material. The test results are agree basically with the theoretical analyses.

Experimental Study on Surface Roughness in Micro-milling of Single Crystal Ni3Al-based Superalloy

Gao Qi, Gong Yadong, Zhou Yunguang

2016, 27(06):  801-804. 

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Two-edged carbide alloy micro-milling tool with 0.8mm diameter was used to study micro-milling surface roughness of Ni3Al-based superalloy. An orthogonal experiment of three factors and five levels was implemented to microscope milling of typical single crystal Ni3Al-based superalloy IC10. The influences of  primary and secondary factors of spindle speed，feed rate，feed depth on micro-milling surface quality were found according to the range analysis.  The ideal cutting process parameter combination was optimized and obtained, the surface roughness is as 801nm. Its cutting mechanism and the reasons  affecting the surface quality were analyzed. The test results have certain guiding significance to the microscope milling mechanism of single crystal superalloy.

Load Feedforward and Feedback Compounded Compensation Controlfor Variable Speed Hydraulic Power Supply

Li Zhao, Gu Lichen, Ma Yu

2016, 27(06):  805-809,832. 

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The principles and characteristics of feedforward control and feedback control were studied，a method called the load feedforward and feedback compounded compensation control strategy was proposed herein to realize the constant flow control of hydraulic power supply under typical operating conditions. Based on the experimental platform of mechanical-electrical-hydraulic system, a Simulink model of variable speed hydraulic power supply was established. The simulations and experiments were carried out respectively under a simple PID feedback control and a compounded compensation control strategy. The results verify the compounded compensation control strategy is efficient and feasible in constant flow control of hydraulic power supply,and the resistance to load disturbance of the compounded  compensation control strategy is superior to the simple PID control .

Model Identification  and Parameter Forecasting  of   Rubber Conveyor Belt Restoring Force

Chen Hongyue, Bai Yangxi, Zhang Yu, Deng Wenhao

2016, 27(06):  810-814. 

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Model identification and parameter identification of a  rubber conveyor belt restoring force were the key problems for  researching on hysteresis energy of conveyor belt. The Gaussian function was used to describe restoring force model, its feasibility and accuracy were analyzed and verified by using the method of  theory  combined  with tests.The test and fitting data were treated as training sample. The restoring force model coefficient under different excitations   was forecasted by using radical basis function neural network which was optimized by the drosophila algorithm. The prediction accuracy was verified by experiments.

Micro Segment Gear Surface Engineering Process Modeling Based on Polychromatic Sets

Yang Qin, Xu Xiang, Chen Liyun, Huang Kang

2016, 27(06):  815-821. 

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According to the complex problems of surface engineering process modeling of product components,polychromatic sets theory was proposed to assist  the  research of  surface engineering process modeling. Firstly, polychromatic set theory was used to in process planning of surface engineering technology and to built mathematical model of the selected method. Surface functional requirement mapping matrix and surface engineering technology requirements contour matrix were established. Secondly, surface treatment technology process requirements were divided into cycle requirements and linear requirements, evolutionary algorithms and polychromatic graph were used to find the solutions of the process routes for two kinds of requirements respectively. Finally, process of surface treatment technology of micro segment gear was used as a verification, and a reasonable surface treatment process route was obtained.

Powertrain in Loop Test System of  Hybrid Electric Vehicles Combined Lithium Battery and Super Capacitor

Zheng Yue, Xie Changjun, Huang Liang, Quan Shuhai , Tan Baohua,

2016, 27(06):  821-826. 

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A hybrid power system combined lithium battery and super capacitor was proposed and designed by using super capacitor's advantages, such as high power density and better charge and discharge properties. A powertrain in a loop test bench was established based on the AC electrical dynamometer. Secondly, the test station powered by a 70.4V/40A·h lithium battery pack and two 48.6V/165F super capacitor bank was designed and constructed on the basis of stand-alone module. The backward test method was designed for the powertrain test bench. Finally, a fuzzy-PID controller was devised for the energy management of hybrid powertrain and an UDDS driving cycle was carried out. The test results show that the charge and discharge currents of lithium battery pack are restricted below 1C, and the most current fluctuation is undertook by super capacitor bank, which can protect the lithium battery pack.

Crashworthiness Design of Automotive Front Rail Using  Topology Optimization Method

Cao Libo, Song Huibin, Wu Hequan, Liu Yafei

2016, 27(06):  827-832. 

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Based on static and dynamic topology optimization. the crashworthiness of automotive front rail was designed.A maximum axial stiffness and a maximum side stiffness of front rail structure form were obtainted through static topology optimization. A maximum energy absorption of front rail structure form was obtained through dynamic topology optimization. Through analyzing the topology optimization results and comprehensively considering  the axial stiffness, the lateral stiffness and energy absorption characteristics, the optimal cross section form and the induced-structure,s size and location of front rail was obtained. The results obtained by constrastive analyses show that the frontal rail crashworthiness is improved.

Key Technologies and Future Development of Hydraulic Free Piston Engine

Ren Haoling, Lin Tianliang, Xie Haibo, Yang Huayong

2016, 27(06):  833-838. 

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Three basic configurations of HFPE, their working principles and merits were introduced. Special characteristics of HFPE due to the unique structure, key technologies and challenges in developing, and research situation of HFPE were discussed in detail. The bottleneck techniques which restricted the industrialization of HFPE were pointed out. The exploration and tries to solve these bottleneck techniques were introduced. Development of HFPE might be carried out through the improved structure, the breakthrough of combustion and fuel technology, and the multidisciplinary integration.

Research Status and Its Perspective of Key Techniques for Cable Harness Virtual Assembly

Wang Falin, Liao Wenhe, Guo Yu, Wang Xiaofei, Gao Yang

2016, 27(06):  839-851. 

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Cable harness wiring and installation were the universal problems in the design of complex mechatronic products. The wiring quality of cable harness became an important indicator to measure the product performance and reliability. Firstly, the connotation and main research contents of cable harness virtual assembly were introduced herein. Then the key technologies and its characteristics involved to cable harness virtual assembly were analyzed especially, and a comparative analysis of research status at home and abroad was also given. The existing problems and future development trends were also presented and analyzed. Finally, the applications of augmented reality in the field of cable harness assembly were discussed.