Table of Content

10 March 2015, Volume 26 Issue 5

Previous Issue    Next Issue

Tool Life for Milling Ti40 Burn Resistant Titanium Alloy with CPMJIC Method

Lü Dongsheng, Xu Jiuhua, Fu Yucan, Ding Wenfeng, Yan Kai

2015, 26(5):  569-574. 

Asbtract ( )   PDF (614KB) ( )  

References | Related Articles | Metrics

 In order to investigate the improvement effects of the CPMJIC in milling Ti40 burn resistant titanium alloy, a comparative investigation on the performance of oil cooling and CPMJIC was conducted. The wear pattern and the tool life of the coated carbide tool were presented. The effects of CPMJIC parameters(target distance, oil flow, gas pressure, oil pressure) on milling temperature were analyzed. Based on the response surface methodology, a milling temperature model was built and experimentally verified in order to determine the best CPMJIC parameters. The experimental results show that CPMJC provides some advantages in terms of tool wear reduction and tool life greatly enhancement. The tool milling temperature model has good reliability and practical value. CPMJIC with gas pressure 0.5MPa, oil pressure 0.5MPa, target distance 5mm, oil flow 83mL/min provides the highest tool life during milling Ti40 burn resistant titanium alloy.

Research on Grinding Parameters in Machining Helical Groove of Cutting Tools with a Dishing Wheel

Zeng Tao, Zhou Zhixiong, Tang Aimin, Xiao Silai, Zuo Xiaochen

2015, 26(5):  575-580. 

Asbtract ( )   PDF (611KB) ( )  

References | Related Articles | Metrics

Based on the theory of non-instantaneous center enveloping, a mathematical model of helical groove was established, and the function of grinding parameters and design parameters were deduced. According to the mathematical model, a human-computer interactive interface used to calculate the grinding parameters and simulate the groove section was developed, and then the section profile of the simulative groove and actual groove were compared. The results show a good agreement and verify the validity of the mathematical model. In addition, variations of grinding parameters and groove influenced by design parameters were simply discussed.

Optimal Design of Flat Spring Used in Thermostat Based on Geometrically Nonlinear Finite Element Method

Chen Wenhua, Li Xiaohui, Pan Jun, He Qingchuan, Chen Xiaoying, Wang Meng

2015, 26(5):  581-586. 

Asbtract ( )   PDF (577KB) ( )  

References | Related Articles | Metrics

A geometrically nonlinear finite element method was applied herein to the numerical calculation of the flat spring used in a thermostat. The calculation results were verified by comparison with experiments. Then the optimal design of the flat spring's construction parameters were completed by using the MATLAB optimization toolbox. At last, the contact bounce of the thermostat was simulated by ADAMS. The results show that the flat spring which is designed optimally based on the geometrical nonlinear finite element method can prevent the contact bounce effectively.

Research on Mobile Robot FastSLAM Based on Chaos Optimization of MPSO Algorithm

Zhu Qiguang, Xia Cuiping, Chen Weidong, Chen Ying

2015, 26(5):  587-591,597. 

Asbtract ( )   PDF (565KB) ( )  

References | Related Articles | Metrics

Aiming at the particle degradation problem of an mobile robot FastSLAM  a chaos optimization MPSO based algorithm was proposed. The algorithm incorporated the newest observation information into the prediction of particle, adjusted the proposal distribution of the particles, and the accuracy of prediction of a robot's position was enhanced. The MPSO was solved by a sequential two-step optimization strategy. Firstly, the speed of evolution of particle was improved by the median-oriented acceleration, the particle degradation effectively was overcome, the convergence of the algorithm was improved. Then, focusing on the depletion of the particle, the chaos search algorithm optimization algorithms was introduced to MPSO global optimal position to disperse gathered at local optimum particle swarm to the global optimum location close to broaden the scope of the solution space, thus maintaining the population the diversity of simulation. The experimental results prove that the improved method is correct and feasible.

Analysis on Non-continuous Constraints and Dynamics Modeling of Quadruped Robot Dynamically Stable Walking with Trot Gait

Lei Jingtao, Yu Huangying, Wang Feng

2015, 26(5):  592-597. 

Asbtract ( )   PDF (505KB) ( )  

References | Related Articles | Metrics

The trot gait cycle was divided into swing phase and supporting phase. The D-H coordinate method was adopted to analyze the kinematics modeling for the robot. When the legs were in supporting phase, the non-continuous constraint force between feet and environment was analyzed based on the principles of centroid movement, and the mapping relationship between the constraint force and the joints generalized driving force can be determined by the force Jacques matrix. The non-continuous constraint force was considered to analyze the nonlinear dynamical equation of quadruped robot, which had the characteristic of variable topology mechanism and non-continuous constraint. The theoretical analysis results were verified by virtual prototype simulation. The study will provide theoretical basis for improving the mobility and dynamic stability of quadruped robots adapting to unstructured environment.

Simulation and Experiments of WEDM-LS Based on Truncated Cone-shaped Thermal Conduction Model

Wang Yan, Yang Lin, Ding Chengcai, Ding Chengye

2015, 26(5):  598-605. 

Asbtract ( )   PDF (740KB) ( )  

References | Related Articles | Metrics

On the basis of formation mechanism of plasma channel in WEDM, a novel heat conduction model with a circular truncated cone shape was put forward for the first time by studying the velocity difference of electrons and ions in plasma channel. Based on this heat conduction model a finite element analysis was conducted considering the typical machining conditions of aeronautical material-Inconel 718 in WEDM to research its the machining mechanism. The influences of discharge energy on maximum temperature of plasma channel and depth of discharge crater were studied systematically. A verification experiment was carried out,which firstly employed acoustic emission testing technology to monitor the machined surface roughness. It shows that the simulation results are in good agreement with measured Rt values of surface roughness. The analysis results of acoustic emission signals collected during the machining process of WEDM reveal that the intensity of acoustic emission signals get stronger with the increase of discharge energy and get weaker as the changing rate of maximum temperature of discharge channel becomes slower. A regression analysis of value of surface roughness and root-mean-square (RMS) value yields a mathematical prediction model with high precision, the error is less than 4.40%.

Load Anti-sway Control of Luffing Motion for Cranes

Cao Xuyang, Yuan Jing, Li Wanli, Ding Chong

2015, 26(5):  606-611,619. 

Asbtract ( )   PDF (658KB) ( )  

References | Related Articles | Metrics

Aiming at the problems of poor precision, low operation efficiency and low security due to the load oscillation of luffing motion for crane,an error asymptotic compensation control method was proposed to minimize the sway angle of load. Based on the analysis of error asymptotic compensation control theory, the error asymptotic compensation controller was designed. Through appropriate adjustments to the two stage compensation coefficients, the sway angle of the lifted load was gradually decreased, meanwhile, the requirements of the acceleration and the pump displacement were met. The MATLAB simulation results show that error asymptotic compensation controller has good robustness and control precision for different ropes and jib lengths. After the crane began to brake, the sway angle is reduced to below 0.003rad in 10 seconds.

Class Ⅱ Synthesis of Cam Mechanism with Floating Flat Faced Pushrod

Li Yanping, Lin Rongfu, Chang Yong

2015, 26(5):  611-619. 

Asbtract ( )   PDF (769KB) ( )  

References | Related Articles | Metrics

Based on the configuration of high-speed printing machine mechanism with flat faced pushrod imported from German which was the evolution of the one with roller pushrod, the conceptions of “skew floating coordinate system”, “support function” and the ideas of “instantaneous one dimensional linear section” and its projection (the instantaneous interval set) were developed. Then, the important concepts of interval set on the rise,interval set on the return and the whole interval set, and the basic principles of solving the allowable selection area of instantaneous/whole flat axis and allowable range of the cam radius r0 were proposed. Furthermore, the whole common analytical formulas were derived and the analytical criterion of the solution existence and its existing form were obtained. The solution scope of the flat angle were searched and presented. Lastly, the problem of class Ⅱ synthesis of cam mechanism with floating flat faced pushrod were solved successfully and satisfactory.

Discrete Free Search Based on Pareto-optimality for Multi-objective Flexible Job-shop Scheduling Problem

Peng Jiangang, Liu Mingzhou, Zhang Xi, Zhang Mingxin, Ge Maogen

2015, 26(5):  620-626. 

Asbtract ( )   PDF (591KB) ( )  

References | Related Articles | Metrics

A discrete free search algorithm based on Pareto-optimality was proposed for solving multi-objective flexible job-shop scheduling problem. The convergence with probability one of the proposed algorithm was demonstrated based on Markov chain and the convergence rate was analyzed based on expected first hitting time. The computational complexity of algorithm was also analyzed. Individuals of algorithm were represented based on job operation and machine assignment, and updated either with small precise steps for local search or with large steps for global exploration in discrete domain. The individuals were compared through adaptive sensibility and Pareto-optimality concept. The proposed algorithm was to retain the optimization individuals, and to guide individuals taking exploration walks towards Pareto-optimality front of multi-objective flexible job-shop scheduling problem. The feasibility and effectiveness of the proposed algorithm were verified by both 10×10FJSP and 8×8FJSP instance.

Robust Scheduling on Flexible Job Shop with Uncertain Processing Time

Wang Junliang, Zhang Jie, Qin Wei, Yin Li, Chen Dingfang

2015, 26(5):  627-632. 

Asbtract ( )   PDF (610KB) ( )  

References | Related Articles | Metrics

This paper investigated the flexible job-shop scheduling problem (FJSP) with uncertain processing time in a multi-type and low-volume environment. A minimax regret based robust scheduling model was built to minimize the makespan. A novel sequential search rule was put forward to reduce the calculation amount of the algorithm and a two stage genetic algorithm was designed to figure out the redundant and optimal solutions. Orthogonal test was designed to optimize significant parameters, and then, a simulation model was established to evaluate the robustness and objective performance of the algorithm. The results show the proposed algorithm has a better performance than genetic algorithm on flexible job-shop scheduling problem under uncertain and dynamic environment.

Assembly Path Panning and Optimization under Complex Environments

Jiang Kang, Hu Long

2015, 26(5):  632-636. 

Asbtract ( )   PDF (542KB) ( )  

References | Related Articles | Metrics

In order to solve the problem of assembly path planning in three-dimensional complex environments, a model of planning space was established by using grid method and the ant colony algorithm was applied to obtain the initial path to avoid obstacles. The dichotomy interpolation optimization was proposed to reduce the original assembly path length. The obstacle avoidance was achieved by using the axis-aligned bounding boxes between target part and obstacles in the planning process. Some example tests were carried out on the assembly path planning and optimization to verify the effectiveness and feasibility of the proposed algorithm by achieving a shortest smooth collision-free path.

Construction of a Planning and Dispatching Model Based on Cellular Manufacturing and Time Task Bus

Wang Xianhong, Shi Guoquan

2015, 26(5):  637-640. 

Asbtract ( )   PDF (510KB) ( )  

References | Related Articles | Metrics

Nowadays, a large amount of problems existing in most of the discrete manufacturers cannot be solved, such as redundant multiple planning and dispatching in each levels, pyramid production management structure, even more complex production management, weak capacity of reaction to the market demands and difficulty in meeting the market demands, etc. In order to resolve the problems existing in the typical manufacturing process above, a new planning and dispatching model and an integration and optimization model based on the concept of time task bus were creatively presented herein. The statistics data analyzed from the applications in the enterprises validated the feasibility of the method.

Wear Trend Prediction of Crane Gearbox Based on OSVR Method with Combined Kernel Functions

Cao Jinran, Feng Yi, Lu Baochun, Zhang Dengfeng, Wu Jian, Shi Shengzheng, Guan D

2015, 26(5):  641-646. 

Asbtract ( )   PDF (569KB) ( )  

References | Related Articles | Metrics

For the nonlinear and nonstationary crane gearbox wear process, prediction precision and efficiency cannot be effectively balanced by using traditional prediction methods. An OSVR prediction method based on combined kernel functions was proposed. The OSVR algorithm can be adapted to time-varying time series and the efficiency can be improved. Simultaneously, the kernel-combined model would be able to improve the prediction accuracy. Experimental results show that the trend of the crane gearbox wear process can be predicted effectively by using the new method, and the prediction is more accurate than the results of the OSVR method with single kernel function and the gray-neural network method.

Wear Recognition on Guide Surface Based on Feature of Radar Graph

Zhou Youhang, Yu Siliang, Zhang Qiao, Zhou Jian

2015, 26(5):  647-652. 

Asbtract ( )   PDF (598KB) ( )  

References | Related Articles | Metrics

To solve the wear recognition problem of machine tool guide surfaces, a new machine tool guide surface recognition method was presented herein based on the radar-graph barycentre feature. Firstly, the gray mean value, skewness, kurtosis, flat degrees and projection variance features of the guide surface image data were defined as primary characteristics. Secondly, data visualization technology based on radar graph was used. The visual barycentre graphical feature was demonstrated based on the radar plot of multi-dimensional data. Thirdly, a classifier based on the support vector machine technology was used, the radar-graph barycentre feature and wear original feature were put into the classifier separately for classification and comparative analysis of classification and experimental results. The calculation and experimental outcomes show that the method based on the radar-graph barycentre feature can detect the guide surface effectively. 

Assembly Sequences Evaluation Modeling and Application Based on Human Factor Simulation Analysis

Ma Hongzhan, Chu Xuening, Liu Zhenhua, Li Yupeng

2015, 26(5):  652-657. 

Asbtract ( )   PDF (613KB) ( )  

References | Related Articles | Metrics

In order to reduce the assembly work fatigue, reduce the intensity of action and improve the assembly quality and efficiency, a comprehensive evaluation model was proposed to evaluate feasible assembly sequences objectively based on human factor simulation analysis. Taking human factor performance of assembly sequences as the goal, a comprehensive evaluation index system including quantitative and qualitative indicators was created as well as human factor engineering simulation analysis model for assembly sequences was proposed, on the basis of it, the attribute value of basic index could be obtained by virtual simulation technology and human factor analysis method.The weights of quantitative index and qualitative index were determined by adopting objective and adaptive entropy method and fuzzy analytic hierarchical process respectively, qualitative evaluation value was quantified using triangular fuzzy number, then based on Topsis framework, the optimal assembly sequence can be drawn. Finally, the evaluation model was applied to a aerospace product reducer feasible assembly sequence optimization combined with Tecnomatix digital simulation platform, verifying its validity.

Fixture Layout Optimization in Multi-station Assembly Processes Using GAAA

Xie Weisong, Deng Zheng, Ding Bohui

2015, 26(5):  658-663. 

Asbtract ( )   PDF (604KB) ( )  

References | Related Articles | Metrics

GAAA (genetic algorithm-ant colony algorithm) was augmented to solve fixture layout optimization problems of 2D rigid parts in multi-station assembly processes, and the coordinates of two locating pins were properly selected to minimize the sensitivity index. The stability and convergence of GAAA were improved by changing the mutation operator, mutation length of genetic algorithm and the position where crossover and mutation occured in ant colony algorithm. A case about automotive side aperture assembly processes was studied to verify the effectiveness of the augmented GAAA. The results show that the augmented GAAA can generate more accurate results with a faster rate of convergence and a better stability than the basic GAAA and ant colony algorithm.

Stability Analysis for Electromechanical Integrated Electromagnetic Worm Drive under Parameter Excitation

Guan Xuemei, Hao Xiuhong

2015, 26(5):  663-667. 

Asbtract ( )   PDF (493KB) ( )  

References | Related Articles | Metrics

The parametric vibration of electromechanical integrated electromagnetic worm drive was caused by external excitation,and indirectly realized through the system internal parameters of periodic changes. The mathematical model describing parameter vibration was an ordinary differential equation of periodic variable coefficient. The system was stable through the rotational inertia fluctuation analysis.The system differential equation was derived by using system parameters of stiffness matrix and a small parameter,and the general solution was obtained by regularization,the determine factors were obtained, the dynamic stability status of the system was confirmed and verified by an example.

SVM α Order Inverse System Decoupling Time-varying Sliding Mode Control of Double Suspension Systems of Machining Center

Liu Chunfang, Rong Gang

2015, 26(5):  668-674. 

Asbtract ( )   PDF (700KB) ( )  

References | Related Articles | Metrics

In order to eliminate the friction between moving beam and guide rail in gantry CNC machine, two suspension systems were adopted to suspend the moving beam jointly, so there were coupling relation between two suspension systems. When the beam suffering unbalance force or external disturbance as the CNC machine working, the existing coupling relationship would influence the two suspension system's air gap, so the machining accuracy of compent was reduced. This paper analysed and concluded the coupling quantitative relationship when beam rolling around the center of mass and moving up and down.In order to eliminate the influence of coupling this paper adopted SVM to approach the two coupling suspension systems's α order inverse system. The obtained α order inverse system in series to coupling systems will be decoupled to two SISO pseudo linear systems.The decoupled SISO system adopted time-varying sliding mode control method. The method can make the system reach to the sliding mode surface directly at any original state, eliminating the process of original state reach to the sliding mode surface. So the sliding control can be achieved using shortest time and can realize global robustness of parameter perturbation and external disturbance. The simulation results show that the proposed method can decouple the coupling system effectively and can approach to the controlled object's α order inverse system without precise mathematical model. The time-varying sliding mode control method has fast response speed and strong robustness ability.

Reconstruction of B-spline Surfaces from Finite Element Deformed Meshes with Consistent Parametric Distribution

Li Tao, Liu Hao, He Gang

2015, 26(5):  675-681. 

Asbtract ( )   PDF (628KB) ( )  

References | Related Articles | Metrics

According to the information of original surfaces, original meshes and deformed meshes, a method for reconstructing B-spline surfaces with consistent parametric distribution was presented. In trimmed regions, initial fitting surfaces were constructed by some operations on original surfaces such as translation, extension, segment and reparametrization, etc. In untrimmed regions, bidirectional skinning method was adopted for the production of initial surfaces after inserting section lines across the highly curved boundaries and revising their parameterization. Then a loop of reparameterizing the nodes and refitting the surfaces proceeded until some ending rules were satisfied. During the process of iteration, a more precise method was presented for determining under-constrained regions by calculating extreme points of basis functions; fairness of the fitting surfaces was improved evidently by splitting coarse meshes to provide enough constraints with interpolatory quad/triangle subdivision scheme. Fitting precision is improved for trimmed surfaces by dint of boundaries and internal nodes interpolation constraints together with shape preservation constraints of under-constrained regions. Test results indicate effectivity of the proposed method.

An Algorithm of Dynamic Vehicle Scheduling Problem Based on Approximate Dynamic Programming

Li Xue, Nie Lanshun, Qi Wenyan, Zhan Dechen

2015, 26(5):  682-688. 

Asbtract ( )   PDF (640KB) ( )  

References | Related Articles | Metrics

Vehicle scheduling in service industry of logistics distribution was presenting features including the tasks tended to be of large scale, vehicles were multi-type and had multiple attributes as well as high demands for real-time scheduling. To solve these problems, this paper proposed a dynamic vehicle scheduling algorithm based on the approximate dynamic programming. An approximate value function was obtained through training of some samples, and according to mission requirements, vehicle state and conditions, and quick scheduling decisions could be made with the value function. The simulation test has proved the correctness and effectiveness of the algorithm.

Mechanical Properties of Micro Plastic Forming Based on Strain Gradient Theory

Guo Youdan, Cheng Xiaonong

2015, 26(5):  689-693. 

Asbtract ( )   PDF (530KB) ( )  

References | Related Articles | Metrics

The unilateral stretching, microhardness, and microbending tests of T2 copper samples with different thicknesses show that the mechanical behavior of material is relevant to the intrinsic characteristics of material: the tensile strength of sheet material with thickness of 30μm is increased by 28% compared with that of the sheet material with thickness of 150μm, the tensile strength of the fine grain with average grain size D of 50μm is improved by 33% compared with that of the coarse grain with average grain size D of 120μm, with the “the finer, the stronger” characteristic displayed. When the ratio of the indentation depth to the sheet thickness is more than 0.2, the deeper the indentation is, the harder the indentation is, with the “the deeper, the harder” characteristic displayed. The springback angle decreases as the thickness of the sheet increases. When the thickness of sheet is less than a certain value (0.06mm), the strain gradient hardening effect of the material makes the change of springback angle with the change of sheet thickness stronger. This change is substantially consistent with the results predicted by using the strain gradient plastic theory.

Research on Relationship  of AZ31B Magnesium Alloy Fracture Strain  and Stress Triaxiality

Zhou Mengcheng, Feng Fei, Hu Jianhua, Lei Yu, He Peng, Huang Shangyu, Zou Fangli

2015, 26(5):  694-698. 

Asbtract ( )   PDF (533KB) ( )  

References | Related Articles | Metrics

Series of quasi-static tensile tests were conducted on smooth and notched round rod made of AZ31B magnesium alloy. ABAQUS software was used to simulate the tensile process of each sample. Part material constants of Johnson-Cook fracture failure model were fitted out, and the relational model between fracture strain and stress triaxiality of AZ31B magnesium alloy were established. Inputing the fracture failure model into ABAQUS for simulation, the simulation results and experimental results are basically consistent, thus the correctness of the fracture failure model was verified.

Transmission Ratio Interval Optimization for Electric Vehicle

Zhao Han, Feng Yongkai, Huang Kang

2015, 26(5):  698-703,709. 

Asbtract ( )   PDF (734KB) ( )  

References | Related Articles | Metrics

In connection with the problem that the transmission ratio optimized by traditional optimization method was often different from the real value decided by gear teeth matching, according to a typical running cycle and in the case of parameters of electric vehicle were set, the drive motor was matched. Taking the transmission ratio as a variable, combining with the two parameters shift schedule, an interval optimization method was established finally. The results show that the maximum feasible interval of the transmission ratio obtained from proposed method can solve the matching problem of gear teeth and make the motor drive system working in the high efficiency areas.

Experimental Study on Effects of DLC Coating on Improvement of Tappet Tribology Characteristics

Li Weijun, Li Zhouyu, Wang Yuanhui

2015, 26(5):  704-709. 

Asbtract ( )   PDF (698KB) ( )  

References | Related Articles | Metrics

In order to analyze the effects of DLC coating on tribology characteristics of valve tappet, tappets with three different kinds of surface treatment were prepared and valvetrain mechanism test bench was built. Then friction loss of valve tappets with different valve tappet top surface treatment was tested under different oil temperature. Surface profiles of valve tappets and cams were tested before and after the experiments to study the surface characteristic and anti-wear ability of DLC coating. The results show that DLC coating can reduce surface roughness of tappet and DLC coating with Si has extremely small roughness. Friction torque between tappet and cam decreases as the rotation speed of camshaft gets bigger and increases when the oil temperature is higher. DLC coating can effectively improve friction loss. Compared with traditional tappet with carbonitriding, DLC coating with Si can cut down friction loss by as large as 20%. Tappets with no coating and with coating without Si have bad anti-wear ability, while DLC coating with Si has prefect wear resistance ability.