Table of Content

10 April 2014, Volume 25 Issue 7

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Research on Identification Approach for Key Geometric Errors of Machine Tools

Zhang Genbao, Fan Xiujun

2014, 25(7):  853-856. 

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The definitions of key geometric errors and impact factors were given and a new method of identifying the key geometric errors was proposed. Taking a precision horizontal machining center as example, the mapping relation model of the machine tool geometric errors and comprehensive errors was built up with the multi-body system theory, by calculating and comparing the impact factors, 16 key geometric errors which affected the accuracy of the machine tools were identified finally. The demonstration shows that geometric error factors that have relatively significant influence on comprehensive spatial errors of the machine tools can be identified effectively, thus an important theoretical basis is provided for improving precision of machine tools reasonably and economically.

Error Model of Machine Tool and Cumulative Error Forecasting Based on Three-dimensional Vector Chain

Huang Qiang, Gao Chanjun

2014, 25(7):  857-862. 

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Error modeling and analysis can provide some important directions to the machining precision design control and error compensation on machine tools. According to the characteristics of topology structure on machine tool, a space error model of machine tool based on three-dimensional vector chain was presented. Based on analyzing action rules of cell errors, the cumulative rules of errors and calculation methods were introduced detailedly, and an application demonstration was given.

Identification of Temperature Measuring Points for Machine Tools with Kohonen Self-organizing Competitive Network

Gao Feng, Liu Jiang, Li Yan, Yang Xingang

2014, 25(7):  862-866. 

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A novel optimization algorithm based on Kohonen neural network for identifying temperature measuring points was presented, where temperature variables and positioning errors at the feeding system in the machine tools served as input sample to train the network. The winners resulted from self-organizing competition were transferred into the corresponding classified modes, so the thermal critical points were determined according to the correlation coefficients among temperature variables and thermal errors in each class. Finally, a thermal error model was established with multi variable linear regression analysis method using optimized thermal critical points, whose results are more feasible and practicable in comparison with the thermal error model based on grouping optimization.

Entity Modeling of Toroidal Drive Based on Tooth Surface Grid

Hong Mei, Yao Ligang

2014, 25(7):  867-872. 

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As the key parts of a toroidal drive the tooth surfaces of the sun-worm and the stationary internal toroidal gear were complex space curved surfaces. The accurate entity model of the sun-worm and the stationary internal toroidal gear had direct influences on the precision of the NC machining. Aiming at the sun-worm digital modeling problems, according to the mathematical model of the sun-worm, the grid division method of the helical tooth surface was given, the method of the toroidal drive accurate entity modeling based on tooth surface grid was put forward and was verified by NC machining. 

Vibration Analysis of Large Scale Process Reciprocating Compressor System

Tang Bin, Liu Guangbin, Xu Haiping, Yang Qichao Wang Le, Zhao Yuanyang, Li Lian

2014, 25(7):  873-877. 

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Vibration faults of a large process reciprocating compressor system were analyzed. The unbalanced forces/moments were firstly calculated, and the vibration amplitude of compressor foundation was checked. Finite element models of shafting of compressor-motor and fluid structure interaction of pipeline systems were constructed, respectively. The first six orders vibration mode and frequency of shafting were obtained by the FEM, and the natural frequency of pipeline system was also calculated by FEM. The results show that the vibration amplitude generated by unbalanced moments is acceptable. The main causes of compressor system vibration faults are from fluid structure interaction vibration of pipeline system. Operating speed of compressor has to be changed to avoid the resonance region of shafting vibration. An improvement program of pipeline system was proposed, by which the natural frequency was increased obviously, and the vibration amplitude decreases to 165μm that meets the demands of standard API618 well.

Rapid Smart Welding Planning System Design for Multi-specification and Small-batch Products

Wang Zhaoqian, Yang Jianyu, Guan Zhenhua, Zhao Haifeng, David Alan Bourne, Wang

2014, 25(7):  878-881,887. 

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The rapid and smart manufacturing is the key technology in the current customizing manufacture, especially on multispecies but small amount. A rapidly welding design method was developed using an advanced RRT algorithm. This new method could be divided into task composer and motion planer. The task composer was built to finish more welding lines without moving the frame. And the motion planer was built to calculate the best route without collision from the origin point to the target using less time. This method is verified about five times faster than the current best practices allowed in the task composing and in the route design speed.

Combination Resonances of Axially Moving Current-conducting Strip Plate in Transverse Magnetic Field

Hu Yuda, Hu Shoupeng, Zhang Yiying

2014, 25(7):  882-887. 

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Based on expressions of total kinetic energy, potential energy and electromagnetic force, the nonlinear magneto-elastic vibration equations of an axially moving current-conducting thin plate in magnetic field were deduced by using Hamilton principle. According to displacement mode hypothesis, by using the Galerkin method, a duffing magneto-elastic vibration equation of axially moving strip plate with two opposite edges simply supported in transverse magnetic field was obtained. Combination resonance amplitude-frequency equation was derived by means of  the multiple-scale method, and the critical condition of stability of steady-state solution was also given. By several numerical examples, the variation curves of the amplitude for different axial speeds, magnetic induction intensities, external excitations and axial tensions were obtained respectively, then time history plot and phase plot were also obtained. The influences of different parameters on the resonance amplitudes and nonlinear characteristic behaviors were investigated, and the quasi-periodic, chaotic motion of axially moving system were further discussed.

Layout Selection and Stability Analysis of a Mobile Robot Based on Single Row Alternate Wheel

Zhou Weihua, Wang Ban, Huang Shanjun, Guo Jifeng

2014, 25(7):  888-894. 

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This paper introduced layout selection and stability analysis of a mobile robot based on the single row alternate wheel. The structure of a single row alternate wheel was presented, the kinematic model was established, the conditions of the system moving in omni-direction through analyzing the system speed inverse Jacobi rank of matrix were achieved, and the arrangement of the three and four wheels which satisfied the conditions was given. Dynamics equations of the system were obtained according to the nonholonomic system of Rolls equations. The rollover and backward conditions of the system moving on the slope were calculated, and the model was simulated by using ADAMS software. This paper provides theoretical basis for system practical applications.

Study on Verification and Compensation of Indexing Errors for Turntable

Guo Jingbin, Cao Hongyan, Wang Kexin, Qi Yongyue

2014, 25(7):  895-899. 

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A multi-tooth indexing table with 0.3″ precision and plane mirror were selected as the angular standard, to check the indexing errors of turntable. With regard to the impact of the installation tilt of multi-tooth indexing table on the test results, a compensation method was proposed. According to the characteristics that the indexing errors of turntable were superimposed by the multiple harmonic waves, the harmonic analysis method was used to fit the measured data. The fitting curve was applied to compensate index errors. After testing and compensating, the indexing precision of the turntable is improved from 17.82″ to 2″, which verifies the validity and feasibility of measurement methods and the compensation model.

Study on Elastically Actuated Joints of Robot for Mimicking Musculo-tendinous Functions Based on SEAs

He Fuben, Liang Yande, Sun Jiefu, Guo Chao

2014, 25(7):  900-905. 

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In order to implement the capabilities of anthropomorphic locomotion and the compliances of contacting external environment in robot system, according to the SEA concept, this paper presented a type of elastically actuated robot revolution joint mimicking musculo-tendinous functions. It aimed at the compliant locomotion under the forced vibrations or the impacts. The joint mechanism refered to the Hill-type model of musculo-tendinous unit in human, untilizing the agonist-antangonist form of actively elastic drive and passively elastic constraint. The elastic actuation mainly imitateed the movements and functions of muscle contraction, which produced pulling force to drive the robot joint. Regarding the equations derived from dynamics analysis and the characteristic curves of joint movements in multiple simulations, the motion laws could be mastered, and the dynamics performances could be evaluated. In addition, for the joint characteristics of strong elasticity and low stiffness, the paper also proposed a virtual stiffness control method. This control approach was implemented in a 2 DOF articular robot arm applied with the elastically actuated joints, whose applicability and effectiveness were demonstrated by the experimental results.

Analysis and Optimization of Configuration Path for Customized Manufacturing System Based on Dynamic Cloud Manufacturing

Shang Xin, Yin Guofu

2014, 25(7):  906-910. 

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Aimed at rapid built cloud-based manufacturing system on engineering spot, configuration path of cloud manufacturng which satisfied demands of customized production was analyzed. This configuration path was a circle that started leading leaguer and ended leading leaguer. Factors which cloud manufacturing leaguers were selected were analyzed, factors were turned into dimensionless numbers. Configuration path was altered in order to adapt dynamic planning and factors were weighted functions in dynamic planning, so optimization mode of cloud manufacturng configuration path was gained and it could use dynamic planning and LINDO to optimize.Finally,an example was discussed.

Equipment Manufacturing Industry-oriented Respond Model of Cloud Manufacturing Service Requirements and Resources

Shen Lei, Guo Gang, Dong Yuanfa, Luo Yu

2014, 25(7):  911-917. 

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For the characteristics of diversity, dynamic, discrete in the process of search, obtaining, matching, trading, using manufacturing service resources by manufacturer, a cloud manufacturing service resource agglomeration mechanism and new business model were presented herein. Equipment manufacturing industry-oriented respond model of cloud manufacturing service requirements and resources was established and solved by intuition trapezoidal fuzzy set algorithm. Feasibility of this model was validated by an example of wind power equipment manufacturing process on cloud manufacturing service platform software application, which provides an advanced and practical method and key technology for promoting the development of the equipment manufacturing services.

Research on Manufacturing Resource Cloud Integration Meta Modeling and Cloud-Agent Service Scheduling

Ma Jun, Luo Guofu, Lu Di, Guo Yanqiang

2014, 25(7):  917-923,930. 

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The manufacturing resource virtualization is the foundation and core of cloud manufacturing services mode. Firstly, the constitution and properties of manufacturing resources were analyzed, and the logic architecture of manufacturing resource perception and track was present by combining of RFID and object name service. Then a virtual manufacturing resource static-dynamic property integration meta-model was built, which provided a unified description mechanism to heterogeneous and virtual manufacturing resources restruction and integration. In this foundation, by combing agent technology with cloud computing technology, a new concept of cloud agent was promoted, and cloud manufacturing service adaptive management and scheduling were realized by means of an improved contract net mechanism based on the resource management agency. At last, a manufacturing resource cloud service platform prototype system oriented to complex product collaboration manufacturing was given, the validity and practicability were illustrated with an example of steam turbine cloud manufacturing service.

Application of Single-channel Blind Source Separation Based on EEMD in Bearing Fault Diagnosis

Li Xiaohui, Fu Pan

2014, 25(7):  924-930. 

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For the problem of extremely underdetermined BSS, which had only one dimensional observing matrix, an algorithm which combining the advantages of EEMD and BSS was used. First, the single-channel was decomposed into intrinsic mode matrix by EEMD, then observing matrix was rebuilt and the estimated sources by joint approximate diagonalization of eigenmatrix was obtained finally. The simulation results show that this method can extract the bearing fault information under low SNR. In experiments, two bearings with different faults were diagnosed, and further confirmed the effectivity of this method.

Bifurcation and Chaos Characteristics of Two-stage Planetary Gear Train Sets

Li Sheng, Wu Qingming, Zhang Zhiqiang, Chen Chongming

2014, 25(7):  931-937. 

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A nonlinear, torsional dynamics model of a two-stage planetary gear train with time varying meshing stiffness, errors of transmission and backlashes was established. The dimensionless equations in generalized coordinates of the system were derived and solved by using the method of numerical integration. The influences of excitation frequency and damping coefficient on the bifurcation and chaos properties of the system were analyzed by using bifurcation diagram, phase trajectory and Poincáre section. The paper shows that the multi-stage planetary gear train system running at high speed and under light load has various nonlinear dynamics behaviors because of the coupling of gear backlashes and time varying meshing stiffness. The periodic response, quasi-periodic response and chaotic response of the system are acquired as excitation frequency increases, and the response of the system will change into chaos in many ways like Hopf bifurcation, etc. Increase of the damping coefficient can make the system narrow the area of complex motion state and expand the area of stable periodic motion state. 

Parallel Disassembly Modeling and Planning Method of Complex Products

Zhang Lei, Peng Hongwei, Bian Benyang, Bao Hong

2014, 25(7):  937-943. 

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To improve the efficiency of complex product disassembly sequence planning, this paper presented a component disassembly sequence programming method of complex products. Structure relationship among components was established based on disassembly constraint graph, then a transitive closure algorithm was applied to cluster all the components, and the product could be decomposed into several parts. Disassembly sequence planning was applied to the connecting components and the clustered parts based on the artificial bee colony algorithm, then the parallel disassembly sequence of complex products could be reached. The generation of the parallel disassembly sequence of a motorcycle engine's components was taken as an example to validate and analyze the above-mentioned method. The results show that the proposed planning method is effective in improving parallel disassembly sequence planning.

Process Improvement and Experiments of Spiral Bevel Gear Forgings Based on Preform Design and Divided Flow Cavity Technology

Gao Zhenshan, Deng Xiaozhong, Chen Fuxiao, Xia Songtao

2014, 25(7):  944-948. 

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Difficult gear tooth corner filling and excessive forming load are the main limitations of spiral bevel gear near net shape forging. Based on the elastroplastic finite element method, the spiral bevel gear forging process using semi-closed die was simulated, and an optimized arc surface cone was proposed for improving the unfilled tooth corner. The influence rules of the processing factors including preforrn height, arc chord height, chord angle and the distance between arc peak and the tooth toe, on the tooth corner filling situation and the forming load were revealed. The best combination of processing factors was chosen by orthogonal experimental design. For decreasing the forming load, the die structure with divided flow cavity was designed, from the simulation results, the forming load decreases more than 22.4%. The experiments were carried out using 25MN electric drive screw press. The numerical simulations and experimental results show that the optimized process mentioned herein is effective.

Reliability Sensitivity Estimation for Implicit Limit State Function Using Fourth-moment Method

Niu Xuming, Sun Zhigang, Kong Chunyuan, Song Yingdong

2014, 25(7):  949-953. 

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The reliability sensitivity estimation for implicit limit state function was proposed by using fourth-moment method and response surface method. The reliability sensitivity of complex structures with arbitrary distribution parameters could be calculated accurately and quickly by combining reliability sensitivity estimation method and finite element method. The reliability sensitivity of two numerical examples such as slider-crank mechanism and pipe joints of pressure vessel were calculated using proposed method, and Monte Carlo method was used to validate the results. The results show that the reliability has little difference between two methods, and the proposed method is more efficient than Monte Carlo method.

Microstructure and Properties of Al Gradient Composites Prepared by Centrifugal Casting

Zhai Yanbo, Ma Xiuteng, Chen Hongbing

2014, 25(7):  954-958,964. 

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The traditional iron cylinder was characterized by poor matching with aluminium alloy cylinder block, and the long-term use might lead to oil and gas spilling. To solve these problems, a new type of cylinder liner made of aluminium gradient composites reinforced by complementary primary Si and Mg2Si particles was prepared by centrifugal casting and using the Al-19Si-5Mg-1Cu-1Ni-1Ti-1Mn alloy as raw material. Structurally, the composites were divided into two zones: a reinforced zone with high volume fraction of primary Si and Mg2Si particles and an unreinforced zone without or few particles. Through a preliminary test of some performance indicators of inner zone and outer zone under normal temperature, the reinforced zone is found to be characterized by the high hardness, high wear resistance and fine thermal stability. 

An Effective Extraction Method of Aviation Engine Blade's Mean Camber Line Based on MLS Method

Zhang Hongying, Li Qidong, Li Wenlong, Wang Xiaobing

2014, 25(7):  959-964. 

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The aviation engine blade is the core component of high performance aero engine, the shape and the machining precision have great impact on its characteristics. Because of its working environment and functional requirements, the geometry shape of the blade was designed to be of variable cross-sections and high twist surfaces. One of the most important parameters to measure the blade geometry was the mean camber line. How to extract the mean camber line of blade accurately and efficiently was one of the problems to be solved urgently. Thus this paper combined MLS method and piecewise isometric curve principle to extract the mean line. This method first divided the engine blade section points into segments, and then the MLS method was applied to make the data of the blade much more intensive. Then, the piecewise isometric curve principal was used to extract the blade mean camber line. Besides, the algorithm accuracy was also evaluated, and the MLS algorithm was worked out when there were noises in the point cloud.

Centroid Location Algorithms of Infrared Target in Computer-vision-based Assembly Pose Detection System

Yang Bowen, Zhang Liyan, Ye Nan, Feng Xinxing, Li Tielin

2014, 25(7):  965-971. 

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For the development of computer-vision-based assembly pose detection system, in order to improve the precision and stability of centroid location of infrared LED target, a gray distribution model of target image was researched, and a new method for estimating the sub-pixel location of infrared LED target based on free surface fitting algorithm was presented, and by bi-cubic spline interpolation according to the gray distribution of target image, the proposed method generated target gray surface and evaluated the sub-pixel location which was the vertex of target gray surface by Quasi-Newton method. Real-data experimental results indicate that in high precision measurement with low noise, the free surface is close to real target gray distribution, the centroid detection has higher precision and stability in high precision measurement,comparing with Gaussian centroid method and weighted gray centroid method, when the targets are at about 5m and 12m distance from the camera.

Research on Electro-hydraulic Synchronization Driving Control for Self-Propelled Transporter Suspension Lifting

Zhao Jingyi, Cheng Fei, Guo Rui, Dai Jianjun

2014, 25(7):  972-978. 

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A multi-domain physical model and a mathematical model were established based on analysis of the mechanical and hydraulic working mechanism of four suspensions synchronous driving system with self-propelled transporter. According to the coupling, nonlinear, model parameter uncertainty characteristics in the leveling system, a self-tuning PID-type fuzzy control based on multi-point output coupling synchronous driving algorithm was proposed, with the four suspensions cylinder actual displacement coupling value as a ideal output, by four independent fuzzy PID controller valve control cylinder was realized respectively to ideal dynamic and static real-time tracking control; The results of the test of synchronous lifting for rated load 1MN self-propelled transporter show that four cylinder dynamic synchronization errors are within range of ±3mm, steady synchronization errors range of ±1mm, with the application of the new control strategy. The new control system has the higher control precision of synchronous driving and better adaptability and robustness from the contrast test.

Research on Vehicle Suspension NVH Performance Based on Flexible-rigid Coupling Model

Li Xinran, Chen Wuwei, Chen Xiaoxin

2014, 25(7):  978-983. 

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The suspension NVH performances under different road excitations were researched herein,and the work conditions could be divided into two types, the road random and pulse excitations. According to the road geometrical shape, the road pulse excitations could be divided into two kinds, the triangular convex block and sine pothole excitations(with brake). Rubber bushings have great effects on the suspension NVH performance. The bushing properties were analyzed, and some other suspension parts were flexiblized by one FEM software. The vehicle flexible-rigid coupling models were established herein. By the method of DOE,the sensitivities of the suspension bushing stiffness in different directions towards the vehicle sprung mass vertical acceleration response were analyzed. Then, some rather sensitive parameters were selected for optimization, and by comparing the simulation results of those models before and after optimization, it can be seen that the suspension NVH performance is improved in the middle and higher frequency band. Finally, the simulation results of the flexible-rigid coupling models were compared with the road excitation machine for verifying the correctness of the simulation models. 

Residual Life Predictions for Bearings Based on PCA and MELM

He Qun, Li Lei, Jiang Guoqian, Xie Ping

2014, 25(7):  984-989. 

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A predictive model of the residual life for bearings based on PCA and MELM was proposed herein. To eliminate the redundancy and relevance within features, PCA was applied to fuse multiple characteristic indexes in both of time and frequency domains which could reflect the running states and degradation trends of bearings. Further, on the basis of univariate ELM, a new MELM model was constructed to predict the remaining life of bearings. Unlike traditional univariate ELM, the proposed method overcomes the problems of the simple structure and the lack of information and can improve the prediction precision of residual life for bearings effectively. The bearing run-to-failure tests were carried out to verify the prediction model, and the experimental results demonstrate that the proposed model based on PCA and MELM has the better prediction precision and stability than that of single ELM model or MELM model.

Research on Crashworthiness Optimal Design of Thin-walled Curved Beam Based on New Type Beam Element Model

Qi Wei, Zhang Weigang, Chen Lina, Guan Xiaojie

2014, 25(7):  989-993. 

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A new type simplified beam model was created for thin-walled curved beam with box cross section. The bending stiffness curve of the thin-walled beam was derived and applied to generate the simplified beam model. Same crashworthiness analyses were performed on both detailed and simplified beam model to verify the accuracy and efficiency of the developed beam model. On the basis of that, response surface method was utilized to establish relationship among design variables and parameters of the bending resistance，and sequential quadratic programming method was applied to optimize the crashworthiness of the simplified model. Judged from the analysis and optimization results, the detail shell model can be replaced by the simplified beam model.