Table of Content

10 February 2015, Volume 26 Issue 3

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An Improved Tool Point Frequency Response Function Prediction Method Based on RCSA

Zhu Jianmin, Wang Jian, Zhang Tongchao, Li Xiaoru

2015, 26(3):  285-292. 

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The present predicting methods of tool point frequency response function (FRF) based on RCSA needed to identify the joint parameters of the spindle-holder and holder-tool joints and to manufacture the artificial tool-holder model, which will result in predicting errors and complexity, aiming at these problems, this paper presented an improved tool point FRF predicting method based on the RCSA. This method firstly improved the present substructure separating methods, and separated the machine-spindle-holder-tool structure into three parts: the machine-spindle-holder-partial tool bar, the remaining toolbar and the tool tooth; then improved the method for calculating the rotating FRFs of the machine-spindle-holder-partial tool bar through inverse RCSA and finite difference method by applying modal impact test on the toolbar, and calculated the FRFs of the remaining toolbar and tool tooth using Euler beam theory;finally the tool point FRF was predicted by coupling the three parts' FRFs. Experiments conducted on a machining center show that the predicted and measured tool point FRFs are in good agreement, the error between the first three order natural frequencies of the predicted and measured FRFs are within 6.9%, the proposed method is feasible, effective and easy to carry out, it can compute the spindle-holder's rotating FRFs directly based on the tool modal experiments, avoiding the identification of the joint parameters and the manufacturing of the holder model.

Theoretical Analysis and Experiments of Ram Gap Compensation's Characteristics

Gu Daqiang, Zheng Yuantai, Gu Weihao

2015, 26(3):  293-298. 

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This paper proposed one solution using elastic deformation of thin-plate actuated by hydraulic pressure in order to compensate the gap between ram and saddle of gantry type milling machine Z axis which might lead to bad stability and consistency during machining. Compensators with different materials or dimensions were designed according to one certain CNC machine. Performance of these compensators was researched both in theory and experiments, the outcome of which shows a linear correlation between deformation and pressure as well as negligible hysteresis for each specific compensator while varies among ones with different materials or dimensions.

Fluid-solid Coupling Analysis of Cantilever Valve in GMM-based Hydraulic Pump

Zhu Yuchuan, Chen Long, Yang Xulei

2015, 26(3):  298-304. 

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A novel structure of giant magnetostrictive pump (GMP) for the hybrid solid fluid actuator was designed. Aiming to fluid-solid coupling characteristics of cantilever valve in GMM-based pump, based on single degree of freedom vibration theory and equivalent calculation principle to parameters of cantilever valve, a linear model describing kinetic characteristic of cantilever valve was established and simulated. Further, aimimg to the nonlinear characteristic of fluid-solid coupling of cantilever valve, a numerical model with Comsol-CFD was built, accordingly numerical investigation for cantilever valve was performed, thus, the interaction relationship among main parameters of cantilever valve and performance of GMM-based pump was obtained, which provides a reference for parameter design and optimization of cantilever valve in GMM-based pump. Finally, the validity of above-mentioned numerical results was validated by comparing the simulation results with the theoretical one.

High Precision Machining Technology Based on Analytical Method for Integral Impeller with Flank Milling

Yu Daoyang, Han Jiang, Zhao Han

2015, 26(3):  304-307. 

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This paper proposed machining non-developable ruled surface cutter axis vector's analytical method, provided the  analytical method's machining error and compared with the “R offset” flank milling method's error. The results prove  that the prposed melhod can reduce the theoretical errors. Then the blade tool path trajectory was drew by the algorithm with MATLAB software. Finally, NC machining experiments verified the proposed algorithm, the machining results show that the machining errors are within the allowable machining error range and the machining surface quality of impeller is good.

A New Method for Workspace Boundary Extraction for Jointed Serial Robot

Hou Yulei, Wang Changmei, Hu Xinzhe, Zeng Daxing, Zhao Yongsheng

2015, 26(3):  308-312,318. 

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Based on the principles of bar limit combined with fixed joint variable, a new method for the workspace boundary extraction——“limit fixed interval angle” was proposed. The ideas and implementation steps was illuminated. Taking the ABB robot as an example, the link parameters and joint variables were set with D-H method. In addition, the transformation relation between the robot coordinate system and D-H coordinate system was established, from which the key point of workspace was obtained. Using MATLAB software, the three dimensional perspective workspace of the robot in the wrist was drew. A comparative analyses reveal that the accuracy of the boundary keypoint satisfies the standard of the commercial robots completely. The method presented herein is simple, effective, easy to calculate and manipulate. The research fruit of workspace of the serial robot possesses important theoretical guiding significance and practical application value.

Body Motion Planning for a Hexapod Robot Based on Relative Motion

Li Manhong, Zhang Minglu, Zhang Jianhua, Zhang Xiaojun

2015, 26(3):  313-318. 

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A hexapod robot in support phase was regarded as a time-varying parallel mechanism to make the kinematics analysis. The determination methods and boundary equations of the workspace were described herein for the hexapod robot whose body posture was given. Based on the relative motion theory, a method to transform body motion planning into foot trajectory planning was presented to simplify the issue of body motion planning. Simulation and experimental results show that the workspace for the hexapod robot in support phase is the intersection of the hollow spheres whose number is up to the number of the support legs and using the principles of relative motion to transform the issue of body motion planning in support phase it is simple and feasible.

Research on Multi-stage Cylinder Lifting System Based on Subsection Control

Zhang Chunhui, Zhao Jingyi, Rong Xiaoyu, Bu Dan,

2015, 26(3):  319-323. 

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Aimed at the lifting tipper impact problems of changing stage of multistage cylinder in mining dump truck, the parameter relationship was studied in the lifting process. A subsection control scheme of load sensitive lifting system was proposed based on electric-hydraulic proportional control. The fuzzy control algorithm was analyzed during changing stage of the cylinder. Simulation analysis shows that the subsection control can improve changing stage impact problem of the multistage cylinder compared with electric-hydraulic proportional control. Through the field test, it is proved that the lifting system solves the control stability of the variable load and parameter time-varying systems effectively，providing reference to analyze the same problem.

Research on Intelligent Three-dimensional Auxiliary Measuring Technique for Large Aircraft Components

Han Feng, Tian Wei, Yuan Zhengmao, Li Mingyang

2015, 26(3):  324-329. 

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A set of intelligent three-dimensional auxiliary measurement system for large aircraft components was developed to realize 3D measurement for profile of large aircraft components with high accuracy,high efficiency and automation.In the system,a guided vehicle was taken as platform and orthogonal three-coordinate servo mechanism which clamped target was taken as carrier and proceeded closed-loop control by real-time feedback target positions of laser tracker to realize error compensation. The off-line programming was adopted to guided vehicle and orthogonal three-coordinate servo mechanism for mission planning.The measurement accuracy and measurement range were ensured,and the automatic measurement of the products was realized.The experimental results show that the measuring system is simple and effective,and has extensive avaliable ranges and good promotional values.

Minimax model and Two Space Co-evolutionary Genetic Algorithm for Job Shop Scheduling Problem

Yang Hongan, Xi Zhicheng, Xia Changkai, Wang Jinguo

2015, 26(3):  330-338. 

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For the job shop scheduling problem with processing time variability, a conservative and robust Minimax analysis method was proposed to estimate the worst scenario and its corresponding bound of scheduling performance indicator. A Minimax model was formulated based on the earli E/T penalty cost of each job. To solve the huge search space problem of traditional traversal or enumeration methods, a convex function theorem was proposed and proved, which can constrict and filter the processing time ranges effectively for a given scheduling sequence, and a kind of job processing times filtering mechanism was proposed based on this convex function theorem. Based on the feature of two space optimization in solving Minimax problem, a two space co-evolutionary genetic algorithm was designed with the consideration of the alternate evolutions between scheduling sequence population and processing time population. Finally, the test results demonstrate that both of the proposed filtering mechanism and two space co-evolutionary algorithm perform effectively.

Research on Manufacturing Resources Allocation and Information Integrated Technology Based on IoT

Liu Mingzhou, Ma Jing, Wang Qiang, Yang Qing

2015, 26(3):  339-347. 

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Research on IoT technology has a significant effect on the development of the manufacturing system. In order to build a manufacturing resource allocation model under the IoT-enabled manufacturing environments, this paper studied the application methods of IoT technology in the mechanical product assembly system, and took the IoT-enabled manufacturing resources as the research object. Then, based on analyzing the manufacturing processes and resource features for mechanical products, and combining the characteristics of the IoT-enabled manufacturing system, a resource classification method of the IoT-enabled manufacturing system was proposed. Accordingly, several mapping mechanism was used for building resource ontology model, mapping model and configuration model under the IoT-enabled manufacturing environments, such as object-oriented resource modeling, resource and task matching mechanism. For realizing the resource sensing and information integration, a framework was put forward to cope with this objective. Finally, a prototype system was developed to verify the feasibility and effectiveness of this method. It is hopeful that the insights and lessons gained from the proposed methods will provide an important reference value for configuring IoT-enabled manufacturing resources.

Improved Food Chain Algorithm for Multi-objective Permutation Flow Shop Scheduling

Chen Kejia, Zhou Xiaomin

2015, 26(3):  348-353,360. 

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An improved food chain algorithm was proposed for permutation flow shop scheduling with multiple objectives of minimizing makespan and total tardiness. Fast non-dominated sorting and crowded distance estimation were introduced into the food chain algorithm to improve the optimization ability based on Pareto optimal solutions. Three typical OR-Library examples were selected to conduct comparison. Numerical results show that the designed algorithm can obtain much better solutions than NSGA-Ⅱ.

Configuration and Workspace Analysis of a Novel Bionic Passive Spherical Hinge with Large Workspace

Qiu Xuesong, Yang Long, Hou Yulei, Zhou Yulin

2015, 26(3):  354-360. 

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The passive spherical hinge is one of the basic units of mechanisms, but the small workspace limits its applications in the design of general mechanical structure. The traditional passive spherical hinge was chosen herein as the prototype and its structure, workspace were analyzed. And then, the binaural bracket fixed type passive spherical hinge and the ball and socket interchanged type passive spherical hinge were proposed by the method of decomposing motion and constraint separately and staggered matching, and the workspaces of the two passive spherical hinges were large. The design idea of offset output was proposed according to the theory of bionic design and the structure of human humerus. Based on this design idea, the ball socket laterally split type passive spherical hinge with offset output and the ball and socket interchanged type passive spherical hinge with offset output were proposed, and the workspaces of the two passive spherical hinges were super large. It is shown that the workspaces increase and their appearance changes correspondingly in pace with the increase of the offset angle of the output rod.The proposed passive spherical hinge expands its application range in the field of the mechanical structure and it has theoretical significance for the development of novel passive spherical hinge.

On-line Compensation Model Based on Real-time Feedback Thermal Errors of Machine Tools

Zhang Chengxin, Gao Feng, Li Yan

2015, 26(3):  361-365. 

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In order to compensate the thermal errors with accurate prediction under various working conditions of machine tools, a novel thermal error prediction modeling method with RFMLS method was presented. As variations in working condition of machine tools, according to real-time online feedback data of temperature and thermal deformation of key measuring points, thermal error model could trace the thermal characteristics by using recursive algorithm to update the model's parameters timely, so the thermal compensation would be carried out successfully. The method was verified by an axial thermal error compensation experiment of spindle conducted on a CNC lathe. The experimental results show that predictive model with RFMLS is more accurate than that with least squares method, the maximum residual error and standard deviation of the former decrease by 52.3% and 67% than those of the latter respectively. Hence the thermal error of machine tools compensated by the presented method can improve accuracy and reduce the model predictive errors effectively.

Preliminary Study of Quantitative Evaluation for Spectrum Load Sequence Effect

Chu Jun, Zheng Songlin

2015, 26(3):  365-368,378. 

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According to the three level program load fatigue test on the 40Cr material smooth specimens with different loading sequences, the influences of load sequence on cumulative fatigue strengthening effect were verified and analyzed. The test results show that, in accordance with the sequence from small to large loads, the exercise loads caused the maximum cumulative fatigue strengthening effect, which approached to the added value of three exercise load's strengthening effects independently. Whereas in other load sequences, the cumulative strengthening effect were decreased in different degrees. Finally, based on the statistical analysis of fatigue test data, a correction factor η was proposed, which expressed the influences of spectrum load sequence on overall cumulative strengthening effect. Moreover, the previous fatigue cumulative strengthening effect model under the random load was modified, which made a deep study of fatigue cumulative theory considering load strengthening effect.

A MFPSO Algorithm for Solving Hydraulic Manifold Processing Shop Scheduling

Chen Dongning, Zhang Ruixing, Yao Chengyu, Qian Yanhui,

2015, 26(3):  369-378. 

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Considering the constraints between processes and machines, an optimization model with the objective of minimizing the maximum completion time or makespan was put forward to solve manifold processing shop scheduling problem effectively.To balance the ability of global and local search of the algorithm,a  MFPSO algorithm was proposed, which used staged search strategy of multi forces. The search process was divided into three stages: earlier-stage, medium-stage and later-stage, and  three kinds of force rules, were correspondingly constructed, which were single repulsion force rule, balanced attraction and repulsion force rule and single attraction force rule. Different force rules were adopted in different search stages so as to improve the search mechanism and search performance of the algorithm. The MFPSO algorithm was applied in solving manifold processing shop scheduling problem. A particle encoding and decoding method was presented based on matrix, which made use of matrix variables to deal with the constraints of the problem. Finally, the MFPSO algorithm presented herein shows better performance compared with PSO  algorithm, median-oriented PSO algorithm, extended PSO algorithm and ant colony optimization algorithm in optimizing manifold processing shop scheduling problem, thus its effectiveness was verified.

Theoretical Calculation and FE Analysis of Springback for 21-6-9 High Strength Stainless Steel Tube during NC Bending

Fang Jun, Lu Shiqiang, Wang Kelu, Xu Xiaomei, Xu Jianmei, Yao Zhengjun

2015, 26(3):  379-384. 

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In order to study the effects of geometric parameters and material parameters on springback of bent tube, the formulas of the final bending radius and springback angle were derived using the elastic plastic theory, then combined with theoretical and FE analysis, the effects of geometric parameters and material parameters on springback law of 21-6-9 high strength stainless steel tube during NC bending were analyzed, then the theoretical analysis, FE simulation and experimental results were compared. The results show that the final bending radius increases with the increase of bending radius, strength coefficient, or the decrease of elastic modulus and hardening exponent, and it is independent of bending angle. The springback angle increases with the increase of bending angle, relative bending radius, strength coefficient or the decrease of elastic modulus, hardening exponent. The simulation results and experimental ones agree with each other well, which can predict springback more accurately. Comparing theoretical analysis with experimental results, the error is bigger, but it can reflect the change trend of springback angle.

Discussion of Plastic Forming for Roller in PRSs

Zhang Dawei, Zhao Shengdun

2015, 26(3):  385-389. 

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The existing production process of roller parts in PRS was analyzed, and the possibility of existing plastic forming processes using to manufacture roller was discussed. A new plastic forming process for mass manufacture of rollers was introduced, where the thread and spline shapes of the roller were formed by simultaneously rolling. The feasibility of the new plastic forming process was investigated by numerical simulation, and this process was also suitable for high efficiency precision manufacture of shaft part with similar features.

Ergonomic Seat Design Based on High-speed Rail Random Vibration Environment Effects on Human Lumbar

Guo Yunpeng, Song Guiqiu

2015, 26(3):  389-393. 

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In order to design a better high-speed train seat and improve the passengers' ride comfort, aiming at the problem that the design standards for the domestic high-speed trains in biomechanics issues was not clearly defined, a human lumbar L1~L5 finite element model was established, and verified by the experiments and theory. The model was analyzed in static state and 350km/h high-speed train running dynamics environment. The static state and structure response of spine were calculated under the action of an external stimulus in order to provide the basis of the high-speed train seat ergonomic design and improve the passenger comfort.

SOC Estimation for Li-Ion Battery Based on Extended Kalman Particle Filter

Zhao Youqun, Zhou Xiaofeng, Liu Yingjie

2015, 26(3):  394-397. 

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As the key parameter for power battery management, the SOC of Li-ion battery described the residual capacity, and indicated the remainder driving range of electric vehicles. The cycles, instantaneous high current, abnormal temperatures and other factors would change cell characteristics, which might introduce larger errors even divergence  over time if the extended Kalman filter algorithm were applied to the SOC estimation. To suppress the divergence and noise, this paper proposed a method based on EKPF algorithm to realize accurate SOC and the current drift estimation on the Li-ion battery mixed noise model. Finally, the superiority of this method was validated by simulation results.

Performance Analysis of Variable Clamping Force Actuator of EMCVT

Ye Ming, Li Xin, Luo Yong

2015, 26(3):  398-402,413. 

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EMCVT was driven by direct current motor. It was more efficient, had less parts and better control performance than that driven by electric-hydraulic system. So far the clamping force of EMCVT could not be varied with input torque. A new type of actuator where the control clamping force was put forward. Mathematical model of clamping force control actuator was built and a dual closed loop controller with fuzzy logic control and PI control was designed. Simulation results show that control performance of clamping force actuator and control strategies are good and meet the requirements of clamping force while system running.

Mechanical Machining Strengthening Mechanism and Material Processing Technology——a Review

Liu Zhanqiang, He Meng, Zhao Jian

2015, 26(3):  403-413. 

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Mechanical machining processes involved micro-structure strengthening mechanism and stress strengthening mechanism were reviewed herein. Material microstructure evolution caused by mechanical machining could improve material performance due to the flow stress increases of the machined workpiece based on the dislocation theory. Theoretical models were applied to explain the mechanism of dislocation strengthening, grain boundary strengthening, strain strengthening and preferred orientation strengthening. The effects of these strengthening mechanism on mechanical machining processes were then introduced and the formations of residual stress in stress strengthening process were presented. The principles of mechanical machining processes and the development status of processing equipment were summarized. The relationship between strengthening mechanism and strengthening process was discussed. In the end, the development perspectives of strengthening process were pointed out.

Present Situation and Development Tendency of Snake-like Robots

Su Zhong, Zhang Shuangbiao, Li Xingcheng

2015, 26(3):  414-425. 

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A literature survey of researches on snake-likes was provided regarding morphology, modeling of kinematics and dynamics, locomotion control and stability. The analyses and summary were made according to the two-dimensional and three-dimensional locomotions. Classifications of snake-like robots were presented due to the differences of structures and movement types. Finally, the development of snake-like robots in future was predicted.