Table of Content

10 March 2014, Volume 25 Issue 5

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Model-based Definition Assembly Process Information Modeling for Aircrafts

Jin Jiangyan, Huang Xiang, Liu Xiping, Li Shuanggao

2014, 25(5):  569-576. 

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To realize the comprehensive application of MBD and get rid of the coexistence of digital quantity and analog quantity in aircraft assembly process planning, a MBD model oriented to assembly process planning was constructed. Through analysis of the aircraft assembly process planning, process informations were divided into four classes: assembly process structure, process features, added process features and supporting information. According to process constitution, the relative mapping operators were customized for all types of information to realize mapping from design model to process model. By multi-view method, all types of process information were represented and managed. And that the process model was divided into three layers: core layer, process extension layer and application layer. Finally, process information MBD model for cabin door was constructed.

Deformation and Compatibility Design of Involute Planetary Gear Drive with Small Teeth Difference

Li Junyang, Wang Jiaxu, Zhou Guangwu, Xiao Ke

2014, 25(5):  576-580. 

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Aiming at involute planetary gear drive with small teeth difference, a design method of deformation and compatibility was proposed, including design of composite gear with multilayer material, material selection and structure design of the elastic layer, and the design formulas for center distance of gear with backlash-free where the deformation of elastic material was considered. On the basis of this method, a filter transmission device was designed and manufactured. The comparative analyses and experiments with the normal planetary transmission driver which had the same structure and specifications was also conducted. The results suggest that filtering gear driver's backlash, lubrication and kinetic characteristics are improved obviously.

Identification of Articulated Robots' Dynamics Parameters Based on Linkage-assemblies Method

Geng Lingbo, Chen Bai, Wu Hongtao

2014, 25(5):  581-587. 

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Based on the linkage-assemblies method, a novel dynamics parameters identification method was presented aiming at obtaining the dynamics parameter values indepent of the suffering loads. All the indepent values of paramaters can be obtained during the identification process of keeping several joints actuated while the rests were locked in a certain method and sequence. Robot dynamics parameter identification program were compiled to calculate the dynamics parameters of a certain industrial robot. The results indicate that all the independent values of parameters can be obtained by this method, and most of them has an ideal accuracy. The low accuracy of few parameters is due to their small contribution to the torque, and when the data is affected by the noise, their information will be submerged. The torque values computed by this novel method are highly close to the the ideal robot controlling values, which indicates the feasibility of this method.

Study on Reliability Evaluation Based on Shock Loads and Performance Degradation

Kang Le, Li Jianlan, Yan Ye, Liu Nian

2014, 25(5):  587-591. 

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A new reliability evaluation method was presented based on the analysis of performance degradation and environmental shock loads. Firstly, according to the performance degradation data, a statistic model based on random coefficient multivariate distribution was given for the analysis of continuous degradation process. A model of shock loads based on Poisson process was used to analyze discrete degradation process. Then the distribution function of actual degradation was obtained by the accumulation of degradation to improve the accuracy of reliability evaluation. Finally, the results of reliability evaluation of metal material performance degradation verify the correctness of this method.

Analysis on Performance of Thermophotovoltaic Devices with Cogeneration

Pan Jianfeng, Hu Song, Tang Aikun, Shao Xia, Liu Yangxian

2014, 25(5):  592-596. 

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By using the TPV technology, thermal radiation can be converted into electricity through a semiconductor PN junction. The advantages of TPV included high power density outputs and theoretical efficiency. A traditional TPV system only output electric energy, but a CHP device which combined heat and power generation recycled energy of exhaust gases and energy of water which can cool photovoltaic cell. By using numerical simulation, the mean temperature of external wall of burner is 1679K; the exhaust gas temperature is 1560K. By mathematical calculation, the electrical efficiency and the thermal efficiency of TPV is 14.07% and 51.70% respectively, the overall efficiency of CHP is 65.77%.

Study on Micro-gripper Based on MEMS Mechanism Assembly

Hao Yongping, Dong Fulu, Zhang Jiayi, Bao Liya

2014, 25(5):  596-601. 

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Micro-gripper as end devices, directly determined the efficiency of the micro-assembly. MEMS mechanism contained many tiny moving parts and functional elements, so as to achieve the stabally gripping and automatic assembly of these tiny devices. A micro-gripper with two grade displacement amplification was designed, which was actuated by piezoelectric ceramics and based on flexible hinges. The micro-gripper node stress, stiffness and maximum deformation, etc. were analyzed and calculated, and the micro-gripper prototype was produced. The experimental results show that the maximum deformation levels of the gripper is as 245μm, the magnification is about 12.3 times, that meets the requirements of MEMS micro-assembly. On this basis of above, the deformation and gripping force were focused on, and a formula of 99.99% reliability drive voltage was derived by nonlinear regression of the test data, and the precise control of the micro-gripper is achieved.

Research on Road Header Gyration Platform's Reliability Based on VPANNs

Zhao Lijuan, Liu Xunan, Sun Qiang

2014, 25(5):  602-607. 

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Taking the project of a type of road header's reliability research as support, based on rock cutting mechanism, a program of road header cutting different consistent coefficient rocks at different horizontal swing velocities with different cutting position angles were generated and the load files were produced by MATLAB. A virtual prototype model of road header cutting rocks was built and dynamics simulations under different working load conditions were done in dynamics simulation software ADAMS. Using fuzzy method, the reliability degree membership function of road header's gyration platform was fitted. Taking different working conditions and relative reliability degree membership function as training samples, a new method combined ANNs and virtual prototype technology was proposed to analyse the reliability. Refer to the reason of ANNs, gyration platform's reliability degree can be forecasted when the road header is working in new conditions, the prediction mean squared errors reach 6.92×10^-6, this method also has instructive significance to practical productions.

Structure Configuration Synthesis of Machine Tools Based on Process Planning of Multi-parts

Huang Hua, Jin Lan, Rui Zhiyuan, Gou Weidong

2014, 25(5):  608-613. 

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A process family of multi-parts was clustered based on the process units to set up the mapping relation between process and structure of the custom machine tool. A kinematic model was established, the moving range was computed and moving style was selected by constraint conditions to make the machining ability satisfy the process requirements of multi-parts, and the flexibility of the machine tool was obtained. The cluster and arrangement of the process lay the foundation for the machine tools customization design and a case was used to illustrate the method.

Stress Design of High Temperature Pneumatic Duct System of Aircraft Using Finite Element Method

Shi Hong, Jiang Yanlong, Liu Juan, Cai Yufei, Liu Chao

2014, 25(5):  614-618. 

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Based on analysis of loads, constraints and its mechanisms applied to the air duct system of an anti-ice system, a strength safety design method of the air duct system was proposed, that is,the beam element model was introduced to analyse the air duct system. According to the simulation results, the duct system was compensated by the compensator and constraint devices in order to meet the design demands of stress and displacement. Then shell element model was used to check out the stress. And the process will be repeated again if the three dimensional calculation results surpassed the demands of designed capacity. The results show that the design method mentioned above can be applied to the safety design of the air duct system of aircraft. Meanwhile, the performance of the ball joint and flight state influencing on stress result should be considered in the design process.

Dimensional Synthesis of a Novel 3-DOF Hybrid Manipulator Based on Stiffness

Hong Zhenyu, Zhang Zhixu, Xu Zhihua

2014, 25(5):  619-623,629. 

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The conceptual design and dimensional synthesis of a novel 3-DOF hybrid manipulator were presented. The manipulator was composed of a parallel mechanism and a rotating platform. The parallel mechanism had two degrees of rotational freedom and was connected with the rotating platform through a turntable bearing serially. It had many advantages such as high stiffness,simple structure. Stiffness was taken as evaluation index and dimensional optimization of parallel part of the mechanism was studied, which was based on velocity mapping model of the 2-DOF parallel mechanism and the singular value theory of Jacobin matrix. Constraint method of coordinate alternation was adopted to seek the optimal solution of the evaluation function. The influence law of scale parameters on stiffness of the mechanism was discussed. A conclusion is that two shifting pairs are parallel and the distance of shifting pairs is equal to the distance of the two ball joint on the moving platform in the optimal solution place. So the effectiveness of the method is proved.

Job Shop Scheduling for Due-time Bottleneck Based on HPSO Algorithm

Lu Jiansha, Deng Wei, Dong Qiaoying

2014, 25(5):  624-629. 

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To solve a kind of job shop scheduling problem for due-time bottleneck, taking the tardiness weighted sum as the optimization objective, a model based on due-time degree of satisfaction and bottleneck resources was presented. According to the characteristics of job shop, a hybrid algorithm with particle swarm optimization and simulated annealing algorithm was proposed to solve the model. In the hybrid algorithm, a random process expression method for encoding was taken. And a dynamic temperature parameter was introduced to the simulated annealing algorithm to increase the algorithm's efficiency. The simulation was given to test the model and algorithms presented herein. And the testing results prove the method is effective.

Estimation of Mean Shift Size in Manufacturing Process with Optimized Multi-kernel Support Vector Regression

Zhu Bo, Liu Fei

2014, 25(5):  630-635,641. 

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In order to estimate the mean shift size in manufacturing process more accurately, a multi-kernel SVR was proposed. The multiple kernel function was convex combination of three basic single kernel functions, i.e. the linear kernel, the polynomial kernel and the radial basis kernel. For constructing the multi-kernel function, PSO algorithm was adopted to optimize the kernel parameters, the weight coefficient and the punishment coefficient C of SVR jointly. And the five-fold cross validation method was applied to compute the fitness value of each particle, which was the average of determination coefficient values of SVR on each of the five groups of samples. As a result, the final multi-kernel SVR obtains good generalization ability. This multi-kernel SVR was integrated with CUSUM chart to monitor and quantify mean shifts in process. The simulation results indicate that it improves a lot on estimating mean shift size compared with the ANN method, and also is superior to SVR with single radial basis kernel. An application examination on actual gear machining process further verified its validity and practicability.

Research on Quartic Polynomial Velocity Planning Algorithm for High-Quality Machining

Wang Yunsen, Gai Rongli, Sun Yilan, Yang Dongsheng

2014, 25(5):  636-341. 

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Through analyzing commonly used velocity planning algorithm in CNC machining, aiming at the CNC machine tool vibration due to unsmoothed velocity，acceleration and jerk during acceleration/deceleration stage, an quartic polynomial acceleration and deceleration control model was proposed. The derived steps of the quartic polynomial velocity equation were also given in detail. Then a parametric curve interpolation algorithm based on quartic polynomial velocity equation was proposed. The algorithm can provide smooth velocity curve, acceleration curve and jerk curve and relieves intense vibration in high speed CNC machining. Simulation experimental results show that the quartic polynomial velocity planning algorithm can realize flexible acceleration/deceleration control and implement high-quality CNC processing.

Turbulence Numerical Simulation and Particle Track Analysis in a Slurry Pump Impeller

Zhang Heng, Yin Yanchao

2014, 25(5):  642-646. 

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In order to improve the pump wear performance and optimize pump design, the flow fields under some work conditions were calculated by solving the N-S equation group with RNG κ-ε model. The algorithm of SIMPLEC was used to correct the compression. Computing about four work conditions of slurry pump, the relative velocity was obtained, and the reflex and peripheral phenomenon were also analyzed; based on the results of flow fields, particle tracks in varied conditions were achieved by using Lagrange method, and the results were visualized. Some particle motion patterns were given involving the effects of particle diameters and work conditions. The results show that the reflex appears in the blade inlet of pressure sides in high flow conditions, but appears in the blade inlet of suction sides in low flow conditions, which possibly induce the cavitation erosion. In low flow conditions, reflex and eddies appear in the blade outlet of both the pressure sides and the suction sides, and the reflex areas even extend to the middle of blades. Particles and heads of blades impact more possibly in low work conditions. With the particle diameter increasing, particles collide with pressure sides more possibly. From the analysis results, this impeller is not suitable for particles whose diameters are more than 1mm and particles of 0.5~1mm are appropriate in the design condition.

Research on Machining Precision Prediction System for Five-axis Milling

Peng Lian, Ding Guofu, Zhu Shaowei, Peng Yu, Ma Shuwen

2014, 25(5):  647-651. 

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Machining process is complicated for five-axis CNC machine, and the machining precision is influenced by many factors. In view of the machining precision prediction method was single for five-axis CNC milling, this paper proposed a view point of several main error combined integrated forecasting, and the computer mapping way was researched in detail; Based on MBS and homogenous transformation matrix (HTM), an error synthesis model was established; then, a prototype system was developed based on VS2010 and OpenGL to predict and display the machining errors intuitively before machining. Finally, a cutting test confirmed that the proposed method is effective and feasible.

Simulation and Experimental Research of SAW Tag

Huang Xin, Chen Zhijun, Chen Tao, Ruan Peng, Xu Hailin

2014, 25(5):  651-656. 

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The SAW tags were simulated using FEM software COMSOL, the SAW tags were produced and tested accordingly. The simulation of the SAW tag included the characteristic frequency simulation, the inter-digital transducer excitation efficiency simulation and the echo characteristics simulation. Three groups of SAW tags were experimentally tested by the network analyzer, the test conclusions are as follows: the characteristic frequency is consistent with the design requirements; the excitation efficiency can be improved by increasing inter-digital transducers aperture; the tag code can be read out by analyzing the amplitude of the echo pulse. The test results are in accordance with the simulation analyses, validating the correctness of the simulation study. Finally, the SAW tag was welded on the printed dipole antenna board to form a SAW tag system and the system was wireless tested, showing the practicability of the SAW tag.

Design and Experimental Investigation on High Efficient Horizontal Micro Electrical Discharge Machine

Shu Xiayun, Zhang Honghai

2014, 25(5):  657-660,668. 

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To improve the efficiency of microelectrode fabrication, this paper proposed a high efficient horizontal micro electric discharge machine, in which ultra-precision diamond wheel grinding method and WEDG method were combined for microelectrode fabrication. The machine consisted of a CCD online dimensional examination system, precision motion and feeding system, nanosecond-pulse independent discharged power supply and gap state-detection system. Experimental study on microelectrode, micro nozzle fabrication and microstructure milling were conducted by the machine. Microelectrode with 15 micrometers in diameter and micro hole with 50 micrometers in diameter were done in experiments.

Conduction Cooperation Method for Product Performance Conflicts Based on Extension Transformation

Zhou Jianqiang, Zhao Yanwei, Hong Huanhuan, Wang Huan, He Lu

2014, 25(5):  661-668. 

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In order to deal with conflict problem of performance optimization in product performance design process, a conduction cooperation method for product performance conflicts was put forward based on extension transformation. Product performance requirements were quantitated and formalized by using the method of extension design, and retrieval mechanism of performance was built for determining the optimal performance. The quantitative mapping mechanism between activity performance and its related product structure was given based on the process. The meeting plan of activity performance was output. Combining the conducting coordination method, the dynamic conduction relationship among the product performance was established. The innovation scheme of product performance design was formated. Finally, screw compressor was taken as an example to verify the feasibility and effectiveness for the method.

General Class Ⅱ Synthesis of Disc Cam Mechanism with Roller Follower Moving in Planar General Motion

Chang Yong, Lin Rongfu, Li Yanping

2014, 25(5):  669-678. 

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The concepts of special and general class Ⅱ synthesis were put forward. By establishing a coordinate system, introducing the concept of “rotation floating axis”, the general class Ⅱ synthesis of the cam mechanism was derived. For the one dimensional case, the solution of instantaneous and whole nested interval and its existing forms were developed. For the two dimensional case, the solution of “nested interval having solution”, “whole nested region”, “whole mechanism solution” and its exiting forms were  developed. And the solution theory of “inferior/non-inferior solution nested region” and “the optimal solution of interval” were presented. Based on Visual Basic 6.0, the visual common software CALRFCY was developed. Lastly, two synthesis examples demonstrate that the offset mechanism is greatly superior to the non-offset mechanism.

Research on Hopf Bifurcation and Chaos of the Single-stage Gear Transmission System

Gou Xiangfeng, Lü Xiaohong, Chen Dailin

2014, 25(5):  679-683,691. 

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In order to investigate the influences of the backlash and other nonlinear factors on the system, a nonlinear dynamics model for a single-stage spur gear pair system with three degree-of-freedom was established wherein the backlash, the time-varying stiffness, the torsion motion and the transmission error were considered. The nonlinear three-degree-of-freedom equations were solved by employing variable step size Runge-Kutta integration method and the bifurcation diagrams were obtained. The nonlinear dynamics characteristics of the system were discussed for the varying of the exciting frequency and classified based on bifurcation diagrams, phase portraits, Poincaré maps and FFT spectrum. The Hopf bifurcation, torus doubling bifurcation, grazing bifurcation and doubling bifurcation are found in the different values of the exciting frequency and their bifurcation points are given. There are two routes from periodic motion to chaos motion.

Automatic Generation of Assembly Tolerance Types Based on Ontology

Zhong Yanru, Gao Wenxiang, Huang Meifa

2014, 25(5):  684-691. 

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To reduce the uncertainty in assembly tolerance design and to satisfy the requirements of tolerance information passing through heterogeneous systems in collaborative environment, ontology technology was introduced to the research of automatic generation of assembly tolerance types. First of all, an assembly tolerance representation model based on spatial relations was constructed. The constraint relations in each layer of the model were represented by OWL (Web ontology language) assertions. Next, by extracting the concepts and relations in the constructed model, an ontology for assembly tolerance representation was constructed and implemented. Based on the implemented ontology and mapping relations among spatial relations and assembly tolerance types, the rules for generating assembly tolerance types were defined by using SWRL (semantic Web rule language). Furthermore, a knowledge base system for generating optional assembly tolerance types was constructed based on the implemented ontology and defined rules. Based on this, an algorithm for automatic generating assembly tolerance types was designed. Finally, the effectiveness of the generation algorithm was demonstrated by a practical example.

Body Assembly Quality Control Based on MEWMA Control Chart

Zeng Chao, Liu Jian, Li Rong

2014, 25(5):  692-697. 

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Considering the characteristics of body assembly size where multi-parameters were involved and the dimensional shift was slow and small, a MEWMA control chart was proposed for monitoring. Based on its performance analysis, MEWMA control chart's deviation  parameter δ,the relation model of upper control limit H and weight parameter r were clarified, and the relational expression of δ and optimum r was obtained as well. In an application example, the value of r resulted from the proposed method is extremely approaching to the statistical optimum value of r, and its MEWMA control chart enjoys better sensibility to small procedure shift, compared with Hotelling's T2 control chart and MEWMA control chart with other values of r.

Adaptive Preview Control of Vision Guided Intelligent Vehicle Lateral Movement

Chen Wuwei, Wang Jiaen, Wang Minglei, Wang Jinbo

2014, 25(5):  698-704. 

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Lateral control of vehicle for lane keeping system should simulate human driver direction control behavior, driver adaptively tuned look-ahead distance according to longitudinal velocity and road curve to obtain desired path following performance. First, a vehicle-road lateral dynamics model was established based on two-degree-of-freedom vehicle model and vehicle-road kinematics. Then a PD controller was designed to track the desired lateral acceleration based on “single point preview optimal curvature model”, a lateral closed loop control system was established, which included vehicle-road lateral dynamics and PD controller, the effects of look-ahead distance, longitudinal velocity and road curve on closed loop control system responses were discussed. Finally, a fuzzy logic controller was designed to choose look-ahead distance based on fuzzy rules so as to make good lane keeping performance and small lateral acceleration. At the same time a way of optimizing fuzzy rules by using GA(genetic algorithm) was proposed to obtain optimal lateral control system performance. Experimental studies show the lateral acceleration is reduced compared with fixed point preview control method and the lane tracking deviation of direction and position decrease respectively by using adaptive preview control.

Experimental Study on Thermoelectric Modules Used in Automobile Exhaust Thermoelectric Generator

Quan Rui, Tan Baohua, Tang Xinfeng, Quan Shuhai, Huang Liang

2014, 25(5):  705-709. 

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To recover the automobile exhaust waste heat with thermoelectric modules, a test setup for Bi2Te3 based thermoelectric modules designed and fabricated by the authors can simulate the automobile exhaust thermoelectric generator (AETEG), the performance of single thermoelectric module with different hot source temperature, cold source temperature, installed pressure, the same temperature difference but different cold source and hot source temperature were tested, respectively. The results indicate that the performance of single thermoelectric module is proportional to the installed pressure and temperature difference between its hot source and cold source, it can be maximized by lowering the cold source temperature appropriately with the same temperature difference, the output current corresponding to the peak power increases as the temperature difference between its hot source and cold source is enlarged. As to AETEG using the about 90℃ water of internal combustion engine as the coolant, the maximum power of single thermoelectric module is above 3W when the hot side temperature is close to the endurance value (350℃) and the installer pressure is above 57kPa. Finally, the optimization design strategy and operation condition of AETEG based on the thermoelectric modules stated above are provided.