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Table of Content

    10 September 2016, Volume 27 Issue 17
    Design and Analysis of Five DOF 3D Printing Parallel Robot
    Pan Ying, Fang Yuefa, Wang Congzhe
    2016, 27(17):  2273-2279. 
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    The design of a novel parallel mechanism for multi-directional 3D printing with five DOF including three translational DOF and two rotational DOF was presented. Its characteristic was that the machine adopted a articulated moving platform to achieve larger workspace. According to the established kinematics model, the inverse kinematics was calculated, the position workspace and the orientation workspace were analyzed, and the velocity Jacobian matrix was established based on screw theory. Kinematic performances, such as singularity and dexterity were analyzed based on the computed Jacobian, the motion simulation was also analyzed. The results show that the 3D printing parallel robot has larger position workspace and the orientation workspace. Although singular location existed, it might be eliminated by means of actuation redundancy and the results prove that the mechanism has better dexterity and is suitable for multi-directional 3D printing.
    Modeling and Analysis for Sampling System of Deep-sea Gravity Piston Sampler Based on Wave Mechanics
    Wen Zejun, Liu Zhan, Jin Yongping, Tian Xuling, Huang Liangpei
    2016, 27(17):  2280-2286. 
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    The working principles and structure characteristics of gravity piston sampler were deeply analyzed herein, the mechanics characteristics of seabed sediments was considered, based on the theory of wave mechanics, the sampling system involving a single rod wave mechanics model was established. Then, the sampling system was carried out the discrete treatments, and the numerical calculation method of the impact sampling process of impact sampling system was researched. Finally, based on the numerical simulation program, the influences of sampler weight stand, impact height, and sampler pipe diameter on the impact sampling performance for gravity piston sampler were analysed, and the impact parts internal stress was also analyzed. The conclusions has important guiding significance to the design and optimization of gravity piston samplers.
    Construction of SLD in Gear Hobbing Process Based on FEA
    Li Guolong, Zhao Jun, Liu Xiaoxu, Yang Yong
    2016, 27(17):  2286-2292,2297. 
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    Aiming at the problems of predicting gear hobbing chatters by SLD where the dynamics parameters were hard to get and the cutting depth was hard to determine, a 3D gear hobbing system dynamics model was established considering cutters arbor flexibility of hob. Hobbing system dynamics parameters was calculated with the relationship between limit chip thickness of hob and axial feed. And the SLD of gear hobbing was drawn based on the model. A hobbing chatter experiment plan was designed, features of steady state cutting and chatter cutting was analyzed via experimental data collected, and chatter frequency and chatter subject was determined, the validity of dynamics model established and SLD was verified. It provides a new method to predict hobbing chatter and to choose cutting parameters.
    Research on Positioning Accuracy Retentivity of Machining Center Based on Residual Stress
    Ma Wenshuo, Mi Jie, Yang Qingdong
    2016, 27(17):  2293-2297. 
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    The relationship between residual stress and the positioning accuracy retentivity of machining center was conducted. Then a new method for quantitative analysis of positioning errors caused by residual stress was proposed. Following the analyses of the processes which produced residual stress, residual stress analyses were carried out on a domestic cartridge receiver machining center bed by using finite element method. Thus the distribution of the residual stress of the bed after casting process and machining process was obtained. Then the deformation of the joint surface between the bed and guide was predicted, which was verified by being compared with the actual measurement. Finally, positioning errors caused by residual stress were calculated.
    Research on Wideband Emissivity of End-face Sliding Friction Pair Interfaces
    Wei Wei, Yu Jianwei, Wang Lifei, Gao Genghu, Yu Xiaofen
    2016, 27(17):  2298-2303. 
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    In order to investigate the wideband emissivity changing rules of the sliding contact interfaces during the friction, a set of experiments were conducted. Taking the end-face sliding interface as the study object, its wideband emissivity after different friction times was measured using thermal imager and self-made device under constant load, constant velocity and molybdenum disulfide grease lubrication. The change regulation of the emissivity was used to correct the brightness temperature obtained by infrared thermometer. The measurement results of the wideband emissivity show a comparatively accurate ones of the self-made devices. The emissivity of the friction contact interface(with lubricating grease and abrasive dust) fluctuates within a certain range in general, and decreases firstly and then increases during the friction processes. The correction of the brightness temperature shows a high precision in the stable friction stage.
    Analysis of Motion Stability of a Mobile Humanoid Nursing Robot
    Yun Jintian, Deng Lihao, Sang Hongqiang,
    2016, 27(17):  2304-2309. 
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    When a nursing robot assisted medical staff to take good care of the patients, the motion stability of the robot was the most concern, which was directly related to the success or failure of the nursing tasks. When the nursing robot lifted the patients with arm and waist, tilting and sliding would most likely to occur. Herein, an omni-directional mobile humanoid nursing robot was taken as the research object, and the motion stability was analyzed from two aspects of static and dynamic. Under the conditions of no load and low speed motion, centre of gravity projection method was used to analyze the static stability; under the load conditions, the theory of ZMP combined with the theory of recursive Newton Euler algorithm was used to analyze the dynamic stability. ADAMS was used to simulate the robot's movement process, which provides the theoretical and simulation basis for the  nursing robot stability.
    Topological Multi-objective Dynamics Optimization of Constrained Damping Structure Based on Evolutionary Structural Optimization
    He Honglin, Tao Jie, Liu Yaodi, Ling Pu
    2016, 27(17):  2310-2315,2321. 
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    Aimed to realize vibration reduction  of damping structure,constrained damping plate vibration optimization was studied. From the constitutive relations of damping materials, the dynamics equation of constrained damping plate was deduced by principle of virtual work, modal loss factor mathematical calculation formula was  deduced based on the energy dissipation. A modal was built, which took maximum the modal loss factor and minimum modal frequency changes as the objective function, damping materials consumption as constraint conditions, the modal loss factor and frequency sensitivity formula was deduced, normalized composite sensitivity formula was constructed. Evolutionary structural optimization was introduced to solve the topological optimization mathematical model, A program of damping structure topological optimization process was given in order to realize simulation calculation of damping plates. The simulations show that multi-objective of the evolutionary structural optimization may significantly improve the vibration reduction effectiveness of the damping material, guarantee the stability of frequency characteristics of the damping plates and greatly reduce the dosage of damping materials. The harmonic response analysis was carried out on the damping plates to verify the effectiveness of the optimization results. The optimization method may be widely used in the design of vibration reduction which have strict requirements in structure dynamics characteristics.
    Research on Fuzzy Adjacent Coupling Synchronization Control in Multi-cylinder Leveling System
    Liu Ruijia, Chen Kai
    2016, 27(17):  2316-2321. 
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    A control method was studied based on fuzzy adjacent coupling for multi cylinder synchronous control of leveling system. Firstly, the leveling force system and multi cylinder control system were analyzed, a nonlinear mathematical model of the controlled objects was built. On the adjacent coupling controller design, a compensator was used to fuse the two adjacent hydraulic cylinder position synchronization error controller of hydraulic cylinder, and fuzzy PID control algorithm was used to get the exact compensation coefficient which was difficult to obtain by conventional method. Through the MATLAB simulation and experiments, the synchronous control method of fuzzy adjacent coupling was tested, and the control of the master slave coupling was used to compare and analyze the results. The results show that the error fluctuation of the four hydraulic cylinders is small, and the errors may be reduced quickly in the hydraulic cylinder plus deceleration phase, which has good synchronization control performance.
    Mechanism Design and Optimization of Self-centering Steady Rest Used in Grinding Machine
    Zhao Yongqiang, Wang Yaofeng, Hou Hongling
    2016, 27(17):  2322-2326,2333. 
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    A prototype of self-centering steady rest for grinding machine was designed; the parameter combinations of steady rest and parametric model of translational cam were established. Optimization design goal and optimization function were presented by combining screening of design parameters. The optimization calculation program in MATLAB was accomplished. Two parameters of the translational cam were optimized based on guaranteeing transmission performance, clamping stability and especially clamping accuracy. So, a complete solution for high accuracy-centering steady rest design was provided.
    Mine Hoist Speed Controller Design Based on L1 Adaptive Control Theory
    Luo Qingshun, Li Jinglan, Liu Hui, Yang Qinmin
    2016, 27(17):  2327-2333. 
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    A mine hoist system dynamic model was firstly analyzed. According to the characteristics of time-variation, nonlinearity, strong coupling, great inertia, unknown load within the system dynamics, a new L1 adaptive controller was adopted to  online learn the operating conditions,to adjust the controller parameters in real time, and well control effectiveness in the global environment was obtained.L1 controller was proved to  have arbitrary steady states and transient tracking precision when the adaptive gain was chosen large enough through strict mathematical verification. Then the feasibility of L1 controller was validated in MATLAB simulation environment and a test was conducted in real mechanical platform. The results show that the mine hoist control system may still track the given speed curve along with satisfactory tracking accuracy and robustness when the load is unknown.
    Failure Diagnosis of Shearer Picks Based on Information Fusion from Multi Sensors
    Zhang Qiang, Wang Haijian, Li Liying , Wen Xuezhen , Nguyen Viet Tuyen,
    2016, 27(17):  2334-2340. 
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    For the problems that the picks failure states for a shearer's cutting head were not easy to identify in the cutting processes,  a method was proposed based on multi sensor feature information fusion. By testing the vibration signals and acoustic emission signals of the picks in different abrasion degrees of a shearer, the signal feature databases of the picks' abrasion and failure were established by using the method of multi sensor feature information fusion of minimum fuzzy membership optimization model to diagnose shearer picks abrasion and failure states. The experimental results show that the accuracy rate of the diagnosis results of picks is more than 95%, which indicates that the method can realize the accurate diagnosis to the states of the shearer's picks .The research results make a great contribution to discover and replace the failure picks, and to improve the service life and work efficiency of the shearer cutting head.
    Flatness Pattern Recognition via GA-T-S Cloud Inference Network Implemented by DSP
    Li Haibin, Gao Wuyang, Lai Yongjin, Zhang Xiuling,
    2016, 27(17):  2341-2347. 
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    The existing neural networks we are mostly software simulation and the training time was long, thus that would not conducive to engineering applications. In view of the above problems, flatness pattern recognition via GA-T-S cloud inference network implemented by DSP was presented herein. Firstly, the DSP's design of T-S cloud inference network was implemented by using TI TMS320F2812 on the basis of flatness pattern recognition via GA-T-S cloud inference network. Then T-S cloud inference network parameters were optimized through genetic algorithm toolbox of MATLAB in off-line manner and these parameters were transmitted to DSP later. The network was run on MATLAB and DSP separately. Finally, the two results of T-S cloud inference network, which was run on MATLAB and DSP respectively, were compared and analyzed. Experimental results confirm that GA-T-S cloud inference network have high accuracy in terms of flatness pattern recognition, it can identify the defect types of flatness correctly. At the same time, the experimental results verify that the T-S cloud inference network can run on the hardware TI TMS320F2812 in a fast speed and it provides a basis for neural networks applied to practical engineering.
    Optimization of Product Functional Requirements Based on Fuzzy Information Axiom
    Geng Xiuli, Dong Xueqi
    2016, 27(17):  2348-2355. 
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    QFD was employed to translate the customer requirements (CRs) and their importance degrees into product functional requirements and their importance degrees. Based on the information axiom, the function requirement configuration concept with the least amount of information was selected. Triangular fuzzy number was used to deal with the fuzzy QFD information. The relative preference relation analysis was provided to process the QFD calculation, and fuzzy information was used to calculate the imformation of qualitative functional requirements. Considering the compensation relationships among the function requirements. a 0-1 non-linear programming model was established with the objective of minimizing the amount of information of function requirements. Finally, an example of product functional requirements optimization for loader was given out to demonstrate the effectiveness of the proposed approach.
    Etching Micromachining of Micro-structure Arrays on Injection Mold Cavity Surface
    Huang Hongguang, Guo Zhongning, Yang Quan
    2016, 27(17):  2356-2360. 
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    A simple mask was designed,and smooth rally micro-structure was researched.It is found that spray pressure is of significant influences on the micro-structure feature,the etching depth and undercut will increase per unit time when spay pressure is growing.Different processing method with controlled spay pressure was integrated to machine rally micro-structure,such as smooth rally micro salient and gradual depth rally micro-structure. Finally,a large rally smooth micro-structure with diameter of 200μm, depth of 60μm was machined.
    Experimental Research and Flow Field Analysis of Impeller Wheel with Inner Spray Lubricant
    Huo Wenguo, Ding Yuanfa, Zhang Xiangyu, Dong Qingyun, Cai Lanrong
    2016, 27(17):  2361-2366. 
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    An impeller wheel structure of inner spray lubrication and grinding method were described herein. The inner cavity solids flow field of the inner spray lubrication wheel was analysed by FLUENT software, the wheel structure with impeller was designed, and grinding experiments were finished through the inner spray lubrication wheel, lubrication grinding performance was analyzed during grinding TC4 alloy. The results show that: solid lubrication of inner spray wheel with impeller precipitated directly to the wheel surface under centrifugal force,throught grinding wheel peripheral pores to suppress titanium adhesion, and the grinding zone temperature and friction coefficient were reduced.
    Analysis of Structure Vibration Based on Out-of-plane Monocular Vision
    Yu Qibing, Yin Aijun, Xue Lei, Zhang Quan
    2016, 27(17):  2367-2371,2378. 
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    Conventional vision measurement had problems of complex system or large amount of calculations. The measurement principles of out-of-plane vision were researched. And combining the theory of modal analysis, the structural vibration parameters were identified by a CCD camera under the normal light conditions. And compared the experimental results and ANSYS shows the method can measure the structure vibration parameters (natural frequency, damping and vibration mode) accurately. The future researches of this method were given in the end of the paper.
    Study on Extraction of Key Functional Components in CNC Machine Tools' Reliability Tests
    Zhang Genbao, She Lin, Ran Yan, Luo Dongmei
    2016, 27(17):  2372-2378. 
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    In the reliability tests, due to the limitations of human resources and other factors, it was not able to test all components, but only to test the machine and its key components usually. Aiming at the problems of lacking theoretical basis and method for key functional components' extraction in CNC machine tools' reliability test, this paper proposes a comprehensive extraction method based on three-parameter interval gray number. This method consider six factors including failure frequently, hazardous, maintainability, complexity, technical level, cost-effective, and their relationship comprehensively, combine the field data with expert experience, conduct a comprehensive assessment for each component with projection index function method, and then extract the key functional components in CNC machine tools' reliability test through Pareto Principle. At last, a domestic horizontal machining center is analyzed for an example to prove this method's effectiveness.
    A Novel Quantitive Calculation Method of Dynamic Misalignment in Rotor Systems
    Chen Hong, Lei Wenping, Chen Lei, Han Jie
    2016, 27(17):  2379-2383. 
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    The kinetic characteristics and motion forms of a twin-rotor system were analyzed from the kinetic point of view, and a novel quantitive calculation method of dynamic misalignment was proposed. The average shaft centerline positions were collected by eddy current transducers mounted on the rotor system, and translation displacements and angular displacements of shaft centerlines were calculated based on similar triangle theorem. Then according to vector synthesis principle, the amounts of the parallel misalignment and angular misalignment of the two rotors at the coupling were obtained. Engineering practices show that the calculation results are consistent with the typical features of the misalignment faults in time wave, spectrum and shaft centerline orbit. The forms and amounts of the misalignment faults might be obtained directly by this method. The novel method benefits the treatment of misalignment faults and shafting alignment in engineering practices.
    Product Disassembly Sequence Planning Based on Improved Artificial Bee Colony Algorithm
    Song Shouxu, Zhang Wensheng, Zhang Lei
    2016, 27(17):  2384-2390. 
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    To improve the disassembly sequence planning rate of complex products, an improved artificial bee colony algorithm was proposed, which was used to find the answers in the process of disassembly sequence planning. Based on the disassembly hybrid graph model, the connection relationships and disassembly priority relationships were expressed, and the constraint expression of disassembly sequence was obtained. The mathematical model and fitness equation of the disassembly sequence planning were constructed. The initial population was given the priority of constraint algorithm. A feasible algorithm for searching and selecting source nectar was put forward. In order to quickly get the disassembly sequence planning of complex products, an adaptive selection parameter was defined to balance the feasibility and fitness algorithm.;Finally, compared with a typical artificial bee colony algorithm, an internal gear pump was studied as an instance to demonstrate the feasibly and efficiency of the method presented.
    Effects of Heat Treatmant on Formation and Mechanical Properties Quality of TC11 and LF6 Dissimilar Metal Friction Welding Seam
    Zhang Changming, Xu Linqing, Zhang Hui, Hou Juncai, Yu Shaojun
    2016, 27(17):  2391-2395. 
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    The continuous drive friction welding and post-weld heat treatment process of TC11 titanium alloy and LF6 stain resistant aluminum alloy were studied. The microstructures of welding zone before and after heat treatment were observed, and the mechanical properties were tested. The conclusions are as follows: before heat treatment, the grain size of weld zone is coarsened; intermetallic compounds may be observed clearly and the micro Vickers hardness increases. A discontinuous thin diffusion layer forms in the TC11/LF6 welding interface after heat treatment at 280℃. After heat treatment, the grain size of weld zone is fine, the bending strength increases by 10.7%, and the micro Vickers hardness decreases by 38%. The optimal friction wilding parameters were determined applying the bending tests and microstructure analysis.
    Effects of Humidity on Ultrasonic Fatigue Crack Growth Rate  of a Cast Aluminum Alloy
    Li Wenkai, Cui Haitao, Wen Weidong, Su Xuming, C C Engler-Pinto Jr
    2016, 27(17):  2396-2401. 
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    Several fatigue crack growth tests on a cast aluminum alloy (A356-T6) were performed herein under different frequencies and humidity levels. The experimented results show that ultrasonic fatigue in dry air and in distilled water have lowest and highest crack growth rate respectively. Conventional fatigue in lab air has almost same crack growth rate as ultrasonic fatigue in distilled water. Wei's fatigue crack growth rate prediction model was modified, which could be used to predict the fatigue crack growth rate for peak aged cast aluminum alloy under different frequencies and humidity levels.
    Evaluation Method for Handling Comfort of Vehicle Gear Shift Lever Based on Fuzzy Neural Network
    Liu Mingzhou, Adilanmu Sitahong, Hu Jing, Zhang Miao, Qian Peilun
    2016, 27(17):  2402-2407. 
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    Aiming at the drawbacks of methods in the comfort evaluation of vehicle gear shift lever, an evaluation method was proposed herein based on fuzzy neural network. The objective evaluation index measured by instrument and the subjective ratings of comfort form subjects during the process of gear shift lever were studied and trained, and finally the evaluation system of gear shift lever handling comfort were established. Computational and experimental results demonstrate the feasibility and applicability of the method.
    Research on Brake-force Distribution Strategies for Brake-by-wire System Based on Slip Ratio
    Peng Xiaoyan, Lü Yibin, He Lei
    2016, 27(17):  2407-2412. 
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    To improve braking safety and stability, an optimal braking force distribution strategy for brake-by-wire system of four-wheel independent break based on slip ratio and a real time optimization calculation method for the constrained optimization problem were proposed, and a co-simulation model of Simulink and CarSim was established to simulate and test.The simulation results show that the optimal braking force distribution strategy based on slip ratio may always ensure the front wheel slip ratio greater than the rear wheels' and the rear wheel slip ratio is optimal under different braking conditions,which improves vehicle braking stability and obtains shorter braking distance. At last, the optimal braking force distribution strategy algorithm is verified and it meets the requirements in real-time.