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Table of Content

    25 July 2016, Volume 27 Issue 14
    Analysis for Influences of Thermal Deformation on Kinematic Accuracy of Slider on Multi-link Punch Press
    Hu Fengfeng, Sun Yu, Peng Binbin, Li Yejian
    2016, 27(14):  1847-1851. 
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    Temperature distribution of cooling oil and the key moving components of a multi-link punch press under different operating conditions were calculated in Fluent. The thermal deformation of moving components was solved by Workbench. And then, trajectory of the slider was analyzed with different thermal deformations. With the increase of thermal deformations, the drift amount of bottom dead is as 0.11mm. Temperature sensor was used to measure the temperature of bearing in real time to verify the results of temperature field simulation. Drift amount of bottom dead center caused by thermal deformation is as 0.098mm by the tests with a displacement sensor. The analytical results and the experimental data coincide with each other.
    Dynamics Modeling and Stability Analysis of a Ducted Fan Unmanned Aerial Vehicle
    Liu Yunping, Chen Cheng, Zhang Yonghong, Li Xianying, Mei Ping
    2016, 27(14):  1852-1856. 
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    The problems of dynamic stability of the ducted fan unmanned aerial vehicles, such as cornering, shake, loss of accuracy of command tracking and loss of control, were very easy to arise during take-off and landing due to the disturbances from the complex airflow. Analyzing the dynamic stability of this system based on solving the dynamics equation or the direct method of Lyapunov was very difficult due to being difficult to solve the equations and to derivate Lyapunov function and so on. Hence, a Lyapunov exponent approach was used to establish the quantitative relationship among the structural parameters of a unmanned aerial vehicle and its dynamic stability for guiding the design of the vehicle's mechanical structure and the optimization of its stability control by using the relationship, which provided important basis for promoting the dynamic stability and reliability of this system. Compared with the direct method of Lyapunov for analyzing of the stability, the method of Lyapunov exponents is easier to build and the calculation process is simpler.
    Research on Robot Control Technology for Finishing Cut Process of Aluminum Alloy Hubs
    Yang Zhongsheng, Huang Yun, , Zou Lai, Ren Xu
    2016, 27(14):  1857-1862. 
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    A robot control technology that integrated teaching programming method with off-line programming method was proposed to complete the finishing cut of hubs by comparing the merits and demerits of these two methods, based on analyzing the structure of aluminum alloy wheel hubs and the requirements of finishing cut. The off-line programing was achieved by using Pieper method to complete robot inverse kinematics solution, according to the points informations of hub surface tool path and robot kinematic equations. The research shows that the robot control technology integrated teaching and off-line programming method satisfies the finishing cut requirements, and greatly enhance the efficiency of hub finishing cut.
    Analysis of Gas Flow Mechanism and Pressure Characteristics between Plates in Micro Scale
    Ning Fangwei, Long Wei, Liu Yan
    2016, 27(14):  1862-1865. 
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    Stratification theory of the gas film was proposed herein, which was based on molecular motion and collision law of the gas in the film between plates. The film was divided into near wall layer, thin layer, continuous flow layer. And the basis for dividing thin layer and continuous flow layer was also given, in addition, physical model and its corresponding equations were proposed. Flow patterns and pressure distribution in the height direction were simulated and calculated by LAMMPS(large-scale atomic/molecular massively parallel simulator). It is concluded that with increasing gas flow rate, the pressure of gas film is decreased, continuous flow layer thickness is increased, the thickness of the thin layer is decreased. There is no layered pressure in the gas film anymore, velocity slippage may be ignored.
    Interference-avoiding Methods between Cutters Back of Disc Cutter with Concave End and CNC Machined Spiral Bevel Gear Teeth
    Li Genggeng, Li Jubo, Chen Meili, Wang Bin, Li Tianxing, Xu Aijun
    2016, 27(14):  1866-1869,1876. 
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    In order to avoid interference between the back of disc cutter with a concave end and gear teeth when spiral bevel gears are machined by a 5-axis CNC machine, the interference-avoiding methods were presented, based on structure of the cutter and gear respectively. According to the position relation between the cutter back cone and the opposite tooth surface,and the normal curvature values of cutter back cone should be higher than the values of the opposite tooth surface,the edge thickness and back cone angle of the cutter were determined, and the interference might be avoided. With a spiral bevel pinion as an example, through comparing the virtual machining tooth surface with the theoretical one, the feasibility of the interference-avoiding methods were verified.
    Research on Floating Sheave Active Adjusting Rope Performance in Multi Rope Winding Hoist Using Electro-hydraulic Servo System
    Ma Wei, Jing Yueshuai, Li Jishun, Zou Shengyong, Xue Yujun, Yang Fang
    2016, 27(14):  1870-1876. 
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    In the working processes of ultra deep mine hoist with multi rope winding, floating sheave active adjusting rope used electro-hydraulic servo system to adjust wire rope tension. According to the floating sheave adjusting the ropes structures and principles the electro-hydraulic servo system mathematical model was constructed,a fuzzy adaptive PID controller of electro-hydraulic servo system was designed, a control method of floating sheave active rope was proposed based on a fuzzy adaptive PID control of electro-hydraulic servo system.The corresponding digital model was built, the vibration of wire rope was simulated with the sinusoidal function of different frequencies, and the dynamic characteristics of hydraulic cylinder was analyzed. Simulation results prove the effectiveness of floating sheave active adjusting rope device based on electro-hydraulic servo system by a fuzzy adaptive PID control method.
    Study on Tool Wear Characteristics during Turning Titanium Matrix Composite Using PCD and Carbide Tools
    Huan Haixiang, , Xu Jiuhua, Su Honghua, Fu Yucan, Liang Xinghui, Ge Yingfei
    2016, 27(14):  1877-1883. 
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    The cutting performance comparison of polycrystalline diamond(PCD) and carbide tools was carried out when turning in-suit TiBw/TiCp reinforced titanium matrix composites at the cutting speed of 60~120m/min. Research results show that three-dimensional cutting force of PCD tools is of approximate 77% to 88% of carbide tools, cutting temperature of PCD tools is of approximate 65% to 82% of carbide tools. PCD tools experienced initial severe wear and stable wear stage, while carbide tools only experienced severe wear stage. Furthermore, abrasive wear and adhesive wear are the predominant wear forms of PCD tools. However, crater wears obviously arised on the rake face of carbide tools are adhesive wear and diffusive wear are the main wear forms.
    Analysis of Free Vibration of Cycloid Ball Planetary Transmission
    Yang Ronggang, An Zijun, Duan Liying
    2016, 27(14):  1883-1891. 
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    In order to reveal the inherent characteristics of cycloid ball planetary transmission accurately, a translational-torsional coupling dynamics model of precision ball transmission was proposed. The relative displacement amount of each component was solved with load. Dynamics of differential equations were deduced, free vibration characteristic equation was given, and the natural frequency and principal modes were obtained. The impacts on the natural frequency of structure parameters was analyzed. Theoretical research was carried out to prove the experiments. The results show that: the mechanism has system-wide vibration mode, the output shaft stationary vibration mode and the output shaft torsional vibration mode; the influence of transmission ratio on natural frequency is uncertain; the output shaft bearing stiffness is a very important parameter of natural frequency that affects the natural frequency; and the correctness of theoretical deduction is verified by experiments.
    Failure Mode and Effect Analysis Based on Rough Set Theory and Taguchi's View of Quality
    Zhang Yanru, Wang Fangxiang, Wang Xiaoqiao, Ge Maogen
    2016, 27(14):  1892-1898,1987. 
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    Aiming at the problems in assessing the risk of failure modes contained actual greater risk in current FMEA effectively, a new FMEA method was proposed based on rough set theory and quality loss function. First, on the basis of potential failure mode analysis, the matrix model of failure modes risk assessment was constructed by expert system. Second, in order to reduce the subjectivity and vagueness of the data itself, the matrix model of risk assessment was converted into rough domain matrix model based on the rough set theory. Third, combined with the solved rough domain matrix, potential loss of each failure mode was solved by applying multivariate quality loss function model. Risk level of failure mode could be sorted according to the potential loss. Finally, an engine assembly process was used as an example to analyze the failure modes and influences. Reasonableness and effectiveness of the proposed method were validated by comparing the results with the current FMEA method.
    Timing Decision-making Analysis Method for Proactive Remanufacturing Based on Performance Parameters
    Ke Qingdi, Wang Hui, Liu Guangfu, Song Shouxu
    2016, 27(14):  1899-1904. 
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    Since the uncertainty in quantity and quality of blanks was the main obstacle in traditional remanufacturing, timing decision-making analysis method for proactive remanufacturing was presented herein based on performance parameters. Informed by the life cycle theory, the variation of production performance in life cycle was shown, and several parameters were analyzed. Moreover, the energy consuming, which was carried as the main variable in this method, was identified in three phases: manufacturing, using and remanufacturing. With establishing the functional model of product's energy consuming, the optimal timing in proactive remanufacturing might be obtained. Finally, one 6-cylinder diesel engine was given as an instance to validate the proposed timing decision-making methods.
    Early Fault Diagnosis for Wind Turbine Gearbox Based on Improved Multivariate Outlier Detection
    Gu Yujiong, Jia Ziwen, Wang Rui, Ren Yuting
    2016, 27(14):  1905-1910,1916. 
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    An improved method of multivariate outlier detection was used in early fault diagnosis for wind turbine gearboxes, which might extract the early fault features under fluctuation working conditions. First, the primitive vibration signals were preprocessed by order resampling, and the processed results were analyzed by dimensionless parameter analysis. Second, a model of early fault diagnosis was created based on Mahalanobis distance, which was used for turbine gearboxes. Finally, the actual data was analyzed by the method of multivariate outlier detection, which was improved by multiple linear regression. The results show that the new method may detect the gearbox faults earlier than original one.
    Fault Diagnosis Based on Semi-supervised Laplacian Eigenmaps
    Jiang Li, Guo Shunsheng
    2016, 27(14):  1911-1916. 
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    Aiming at solving the problems of insufficient labeled fault samples and high-dimensional nonlinear fault data, a fault diagnosis model was proposed based on semi-supervised LE algorithm. The model directly extracted the low-dimensional manifold features from the raw high-dimensional vibration signals, by implementing LE algorithm. The features were fed into semi-supervised classifier based on LE algorithm. Thereby, the operating conditions of mechanical equipment were recognized. Compared with the traditional methods, the model is able to obviously improve fault recognition performance of rolling bearings and gears.
    Flank Milling Cutter Path Optimization Method in Spatial Cam Machining Based on Reconstruction of NURBS Ruled Surface Driven by Sensitive Points
    Hu Dongfang, Zhang Wenbo
    2016, 27(14):  1917-1924. 
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    A new method to improve the tool path accuracy of frank milling was proposed based on the sensitive points affecting the NURBS ruled surface reconstruction for cam machining. The approach for the surface reconstruction was analyzed, and the curvature extreme points and the points with the maximum path error were defined as the sensitive points. The original data points was obtained by the adaptive sampling mesh planned by the curvature extreme points. Based on the least square method, the shape of the ruled surface reconstructed was modified by the constraint curve defined by the error sensitive points. At last, the numeral calculation and simulation experiments of the theoretical machining error model show the effectiveness of the algorithm.
    Method for Surface Crack Detection of Welded Structure in Pulsed Eddy Current Thermography
    Liu Xingle, Liu Zhiping, Li Xuan, Jiang Lei
    2016, 27(14):  1925-1931. 
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    The physical properties and surface of weld led to the infrared complex thermal image signals and the lack of surface crack detection method of welded structure in pulsed eddy current thermography. It was difficult to apply pulsed eddy current thermography technology in metal welded structure of crack detection. A method for surface crack detection was studied herein based on similarity of 3D temperature surface and evaluation index system. The experimental results show that this method may identify the surface crack effectively and realize quantitative analysis, as well as dispense with the prior information and reduces testing complication and cost, thus it owns a high engineering application values.
    Parameter Optimization of Support Vector Regression and Its Applications to Pressure Prediction of Intelligent Pressure Reduce Valves
    Tong Chengbiao, , Zhou Zhixiong, Zhou Yuan
    2016, 27(14):  1931-1935. 
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    Intelligent pressure reduce valve might regulate the downstream pressure by controlling the diaphragm cylinder pressure. Diaphragm cylinder pressure was the control goal of pressure reduce valve intelligent controller, so it was necessary to forecast the diaphragm cylinder pressure according to upstream pressure and downstream pressure. Thus, the parameter optimization method for SVR was proposed based on artificial chemical reaetion optimization algorithm(ACROA-SVR). Furthermore, the ACROA-SVR was applied to the pressure prediction of the diaphragm cylinder pressure herein. By analyzing the experimental data, ACROA-SVR was compared with SVR based on genetic algorithm and traditional SVR. The efficiency and superiority of ACROA-SVR was shown by the analyzed results.
    Reliability Allocation of Key Subsystems of CNC Lathes Based on FMECA Modified Criticality
    Wang Hao, Zhang Yimin, Yang Zhou, Zhou Yanxun
    2016, 27(14):  1936-1941. 
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    Based on FMECA theory, taking the modified criticality values of key subsystems of CNC lathes as allocation criteria, the reliability allocation was conducted. By making severity nonlinear, considering the cost of reducing failure rate, an expression of modified criticality was obtained through combining them, and the importance of failure mode effect level through design process could be vividly reflected. Criticality analysis theory was explained, and then reliability allocation methods were pointed out based on traditional and modified criticality respectively. Finally, a real case of reliability allocation of key subsystems of a CNC lathe was presented applying the methods illustrated before and the comparison between traditional method and modified criticality method was conducted. Results show that the reliability allocation method based on modified criticality herein gives full consideration to effects of subsystems with high severity and difficulty level of reducing failure rates, which can guide reliability design based on results of reliability allocation effectively. More attention must be paid to subsystems with high criticality values and low reliability in aspects such as outsourcing, design, processing and assembling so as to ensure that mean time between failures(MTBF) of CNC lathes can meet the requirements.
    An Energy-saving Partition Control Method Drive System for Hydraulic Presses
    Liu Zhifeng, Li Lei, Huang Haihong, Gao Mengdi, Li Xinyu
    2016, 27(14):  1942-1948. 
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    To reduce the energy consumption of hydraulic press, an energy-saving partition control method was proposed. Several hydraulic presses were grouped to share the only drive system which was partitioned into several regions corresponding to hydraulic press operations named drive zone. The same operations of different hydraulic presses were carried out with the drive of the same drive zone. The output power of each drive unit matched the consumed power of the operations corresponding to the drive unit after energy efficiency optimization. The scheduling method of hydraulic press group was analyzed to ensure that different hydraulic presses in a group shared a drive zone in different time after the adjustment of working beat. The working processes of hydraulic press group were tested and analyzed. The results show that the energy consumption reduces by 40%, and the efficiency of a single hydraulic press increases by 13.3%.
    Friction Regularity of Screwdrills Stator Lining in Different Hot Muds
    Han Chuanjun, Zheng Jipeng, Zhang Jie, Chen Fei
    2016, 27(14):  1948-1952. 
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    The abrasion of the stator rubber lining easily led to the premature failure of the screw drill and lower efficiency. The tribological experiments of the stator rubber lining were carried out in dry mill state and different muds to study the friction and wear characteristics of rubber lining in drilling conditions, and the rubber wear was measured by using electronic measuring scales . The results show that: under low load and speed conditions, the friction coefficient of the rubber decreases with the increase of the load and the speed in each slurry and dry grinding medium. The amount of wear of the rubber increases with the increase of load and speed; in mud medium, the amount of wear rubber also increases with the increase of mud density. The wear mechanism was mainly affected by lagged wear, oxidation degradation and micro-cutting action wear.
    Hydraulic Loading Test Bench for Cutting Part of Shearer Based on Secondary Regulation
    Wang Jie, Wang Hui
    2016, 27(14):  1953-1959. 
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    Based on secondary regulation technology, an enclosed hydraulic loading system scheme with energy harvesting capabilities was put forward to solve the difficulties such as large energy consumption, energy recovering and utilization. This system realized the driving and simulated loading function to the test part, and achieving the energy recovering and utilization by using the symmetric structure with two secondary regulation elements connected in the constant pressure network parallelly. The overall structures of the system, the working principles and control system of the simulated loading system were presented in detail. At last, under 350kW installed power, based on the simulation and the experimental research, the results show that the energy recovery loading system may be loaded with good static characteristics and dynamic characteristics, the speed and torque regulation function may work efficiently. The power recovery rate may come to more than 40% at high load, thus the new system's energy-saving effect is remarkable than usual.
    Finite Element Simulation of Metal Rubber Damper Random Vibration
    Zou Guangping, Liu Ze, Liu Song, Cheng Hezhang
    2016, 27(14):  1960-1963,1981. 
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    A finite element simulation method of random vibration for metal rubber damper was put forward. The orthotropic anisotropy damping material was used to simulate metal rubber, and the related simulation parameters were determined through the sine sweep experiments of the metal rubber damper. The finite element simulation of metal rubber damper random vibration was done via ANSYS Workbench. Simulation results was compared with the experimental ones. Results show that the proposed finite element simulation method can well simulate metal rubber damper random vibration and the calculation results with high accuracy.
    A New Method for Judging Criticat Speed of Nonlinear Bearing Rotor System
    Wang Jianghui, Xu Wubin, Li Bing, Li Xiaolei
    2016, 27(14):  1964-1968. 
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    The theory of computation on discriminating the whirling speed and some shortcomings existing inside the nonlinear sliding bearing rotor system were introduced herein. The scope of the logarithmic decrement was pointed out,which was suitable for the stability critical curve dimensionless eccentricity between 0.2 and 0.6. A new method for judging the critical speed by MATLAB graphical programming was proposed, which was compared with the logarithmic decrement method.The results show that the graphic method to determine the critical speed is correct and the deficiency of the logarithmic decrement method is corrected.
    Optimization Design of a Micro Gripper Based on Kriging Model
    Hu Junfeng, Cai Jianyang, Zheng Changhu
    2016, 27(14):  1968-1975. 
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    In order to tradeoff the opening distance, gripping force sensitivity and rapid response of a novel micro gripper, a optimization method was proposed based on Kriging model. Latin hypercube sampling method was used to select test points, and the response values corresponding to each test point were calculated by using ANSYS. The correlation analysis was carried out to determine the structural parameters affecting performance greatly, and the parameters were selected as the optimization design variables. The nonlinear model reflecting the relationship between the performance index and the design variables was built by using Kriging theory, and the multi-objective optimization model was established. The comparative analyses of the performance indexes before and after optimization show that the magnification ratio increases 7.4%, the natural frequency increases 16.46%, the output stiffness increases 9.84%, the maximum stress decreases by 5.75%. It illustrates that the proposed performance optimization method is effective.
    Modeling and Control of Vehicle Active Stabilizer Bar System with Hydraulic Motor
    Zhao Han, Zhao Fumin, Huang Kang, Shao Ke, Sun Hao
    2016, 27(14):  1976-1981. 
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    Taking active stabilizer bar system with hydraulic motor as the object, a nonlinear dynamics model of active stabilizer bar system with hydraulic motor was established. The controller was designed with the control method for the feedback linearization sliding mode. And the stability of the control system was analyzed by Lyapunov stability theory. On the basis of the CarSim-MATLAB/Simulink co-simulation of the active stabilizer bar system, the response curves on the double-lane-change conditions were achieved. A real vehicle test was also worked out for the verification of the desired control method. The results show that the active stabilizer bar system has the preferable characteristics of anti-roll and ride comfort compared with the passive stabilizer bar.
    Lightweight Design of Vehicle Based on Multiple Hybrid Meta-model Method
    Gu Jichao, Xu Dongyang, Li Guangyao, Gan Nianfei, Fan Tao
    2016, 27(14):  1982-1987. 
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    Aiming at the complex and expensive black-box problems in engineering, a multiple hybrid meta-model based global optimization method was proposed. In the proposed method, three sets of meta-models were employed in the search of the design space simultaneously, each of which included the well-known Kriging, quadratic function and radial basis functions. After the proposed method was applied to the rear frame of a vehide, the mass of the rear frame is reduced by 7.2kg, and subsystem stiffness is also improved. The study shows that both of the search efficiency and accuracy are noticeably improved compared with hybrid and adaptive meta-modeling method.