Table of Content

25 July 2014, Volume 25 Issue 14

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Design and Experiments of Slip Seal Structure Cathode in ECM of Blisk

Liu Jia, Zhu Dong, Wan Longkai, Zhu Di

2014, 25(14):  1847-1851. 

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On the area of blade tip, it is easy to have processing accident in ECM blisk. By using finite element method, the flow field of processing areas was analyzed. The results reveal that the change of sectional area in blade tip is significant.
In order to improve the flow field stability in blade tip area, a new slip seal structure cathode was proposed. The flow field with slip seal structure cathode was analyzed by finite element method. The results reveal that flow field stability in blade tip area is enhanced obviously. The continuous processing experiments about blades was carried out to evaluate  the processing stability of slip seal structure cathode. The results show that the processing stability is improved significantly. The test specimens have batter processing repeatability and surface quality.

Analysis on Output Characteristics of Threedimensional Parallell Kinematics Vibrating Screen Based on Input Optimization

Li Ju, Zhao Dean, Shen Huiping, Deng Jiaming, Huang Tao, Xiong Kun

2014, 25(14):  1852-1857. 

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To study the influences of input change of vibrating screen on output characteristics of mechanism, this paper analyzed the output characteristics of three kinds of parallel kinematics vibrating screens with three, two and one degree of freedom. First of all,the output curves of screen surface motion of three vibrating screens were analyzed. Then the process of grain screening was simulated and analysed based on the discrete element method(DEM). Finally, grain screening experiments were made on the prototype of optimization model. The results show that one degree of  freedom parallel vibrating screen with three dimensional outputs satisfies the requirements of grain screening and features simple, reliable, low cost, low energy consumption and easy operation.

A Forming Method of Grinding Wheel Based on Magnetic Field Control

You Yongfeng, Chen Fengjun, Gong Sheng, Yin Shaohui,

2014, 25(14):  1857-1860. 

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A forming method of grinding wheel was introduced based on ringmagnetic field control to make abrasive particle arrange regularly. A forming device of micro diamond powder wheel was designed. Its magnetic circuit and ringmagnetic field distribution were simulated. After observing the magnetic field distribution, the grinding wheels were produced in the forming device and tungsten carbide test specimens were ground. The surface roughness value of test specimens is  as 29nm. Compared with grinding wheels non magnetic field control forming, the surface quality is improved obviously.

Ontology Driven Modeling of Diagnosis and Maintenance Knowledge for Mechanical Equipment

Qin Dali, Yu Dejie, Liu Jian

2014, 25(14):  1861-1866. 

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In order to improve the accuracy and reliability of mechanical fault diagnosis, a semantic representation for diagnostic maintenance knowledge was introduced. By building the model of equipment structure, empirical maintenance knowledge and diagnostic process, an ontology driven inference model of fault diagnosis was established. An ontology mapping algorithm was proposed for the mapping between the devices' operating status and fault symptoms, and a diagnostic instance matching algorithm was proposed to map the symptom space into the fault case space. As a result, the static maintenance knowledge and the dynamic diagnostic process were consolidated, furthermore, the automation and intellectualization of fault diagnosis and maintenance decisions were achieved. The proposed reasoning model was applied to a rotor fault diagnosis, which demonstrates that the proposed reasoning model can get more accurate realtime diagnostic results.

Gradient Residual Stress Induced Elastic Deformation of Multilayer Structures

Dong Jian, Jiang Heng

2014, 25(14):  1867-1871. 

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A kind of Stoney extended formula was proposed to characterize the relation among the deformation of the multilayer structures and the gradient residual stress in each layers. The Stoney extended formula of trilayer structures was deduced herein, which was used to arrive at the solutions for a trilayer cantilever with gradient residual stress distributions throughout the thickness. A Si3N4/p+ Si/Si multilayer cantilever structure was fabricated and the measurement of its bending curvature was also conducted. Analytical calculation and finite element simulation were carried out considering a p+Si layer with gradient residual stress and mean residual stress,respectively. The presented results herein show that this approach is a precise way to characterize the relation between the elastic deformation of multilayer MEMS structures and arbitrary residual stress distributions throughout the thickness in each layer. The results also show that there will be a larger deviation of displacement if the gradient residual stress is replaced by mean residual stress.

Design Parameter Optimization of Air Cushion Belt Conveyor Based on Comprehensive Energy Consumption

Liu Jian, Guo Sheng, Qu Haibo

2014, 25(14):  1872-1877. 

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The design parameters of air cushion belt conveyor were studied based on system comprehensive energy consumption. An intelligent experimental platform was developed. The data of the air chamber pressure and flow rate were collected, and the relationship between the air flow rate and the length of conveyor was obtained with the same air chamber pressure and load. Some experiments of different pore arrangements were completed, and a comprehensive energy consumption model of air cushion belt conveyor was put forward. The optimal running state and working point with full load were obtained. Further, the fan selection guide of the air cushion belt conveyor with arbitrary length was proposed.

Numerical and Experimental Analysis of Rough Surface Based on NCGM

Tang Jinyuan, Liao Dongri, Zhou Wei

2014, 25(14):  1878-1882. 

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This paper used the time series model, linear transformation method and Johnson transform system to generate rough surface. In order to reduce the memory requirements and for easy convergence, the NCGM was used to solve the  autocorrelation matrix. To illustrate the numerical procedure, some rough surfaces having Gaussian and nonGaussian height distribution and an exponential autocorrelation function(ACF) were generated. The results show that the method can generate the prescribed height distribution and autocorrelation function based on actual processing the surface effectively.

An Optimization Method for Hob Relief Grinding

Chen Jiu, Liu Fenglin, Kang Quan

2014, 25(14):  1883-1887. 

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Highprecision hob relief grinding is the important guarantee of hob accuracy, and hob regrinding is used to prolong hob life. Traditionally, hob relief grinding took the cutting edge on hob rake surface as reference cutting edge, and the regrinding errors increased with the increase of regrinding angle. Herein, an optimization method about hob relief grinding was presented. By taking theoretical cuttingedge with a certain regrinding angle as reference cutting  edge, within the permitted regrinding error, the regrinding error will decreases firstly and  then increases with the increase of regrinding angle. Finally, an instance was calculated, the results verify that the proposed method is feasible and effective.

Forcefight Problem in Control of Aileron's Plane

Zhang Ying, Yuan Zhaohui, Wang Wenshan

2014, 25(14):  1893-1900. 

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To reduce or eliminate the forcefight phenomenon of single feedback loop of redundantchannels, the mechanical transmission structure, plate valves, parallel actuating cylinders, spindle and pipelines of the whole control system were modeled and simulated to obtain the bandwidth frequency of the system and the fightingforce caused by the internal asymmetry of the steeringgear.Then the influences of the system's input ratio,the size of valve's dead zone and the gradient of the valve's open area on the system's fightingforce and response speed were studied. Simulation results show that setting the dead zone of the valve which controls the feedback loop smaller is conducive to the decrease of system's fightingforce, and with the increase of the input ratio the fightingforce will be reduced greatly and the bandwidth will be increased and with the reduce of the valve's dead zone, and the increase of the gradient of the valve's open area, the bandwidth frequency increases, but have no influence on the fightingforce. Therefore, increase the input ratio and reduce the valve's dead zone or appropriate increase the gradient of the valve's open area can improve the dynamic and static performance of the system. Finally, a method of setting a variable orifice put forward  to reduce system's fightingforce when these structural parameters cannot be changed, and simulation results prove its feasibility.

Evaluation Criterions for Movement Scheme of Large Robotic Automatic Press Lines

Zhou Yulin, Zhang Zhiqiang, Hou Yulei, Wang Jianxin, Yu Baolin

2014, 25(14):  1900-1904. 

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Taking the motion performance of robots in a large press line and the minimum distance to adjacent robots as assessment factors, two evaluation criterions were proposed for the movement schemes of large robotic press linesutilization ratio and overlapping rate. Further, “the equal division of time & the matching of movements” method was applied to the movement scheme design for a large robotic press line, and the proposed evaluation criterions were used to evaluate the schemes of movements. Finally, based on the design of the action program, motion simulation was carried out on the production line to verify the correctness and conveniency of the evaluation criterions. The proposed evaluation criterions can provide theoretical reference for the movement scheme development, assessment and control of large robotic press lines.

Selfcalibration of One Dimensional Positioning Accuracy Based on Least Square Method

Guo Tiantai, Wang Xiaoxiao, Hong Bo, Zhao Jun, Kong Ming

2014, 25(14):  1905-1909. 

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In order to improve the positioning accuracy of measuring instruments, a self calibration method to separate the system errors of instruments was presented, which used a measurement scale whose accuracy was less than or equal to the instrument to be calibrated as an intermediary. Several different poses were obtained through translation of the measurement scale, then measurement data of every mark point was acquired, and finally the system errors of the instrument were separated using the proposed self-calibration algorithm. The simulation results show that regardless of existing random measurement noise, the algorithm can separate the system errors of the instrument effectively. Experimental research also confirms the effectiveness of the proposed algorithm.

Dynamic Prediction Method of Multibottleneck in Manufacturing Shop Based on Two Bottleneck Degrees

Liu Zhi, Jiang Zengqiang, Gong Bengang

2014, 25(14):  1910-1915,1921. 

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Aiming at the prediction problem of multi-bottleneck in complex manufacturing shop, a dynamic prediction method of multibottleneck was proposed based on two bottleneck degrees, which can forecast bottleneck accurately under conditions that bottleneck responsibility was verified reasonably. Firstly, conceptual models about general bottleneck degree and independent bottleneck degree were built, and then taking time, quality and cost as parameters, their mathematical models were established. Secondly, one dynamic prediction method of multibottleneck was come up with, which contained duallayer multibottleneck prediction mechanism, bottleneck polymorphism analysis and the iterative prediction of bottleneck index. Finally, it is  proved to be superior and credible by comparison to the method of single bottleneck degree and the method of PBM for production bottleneck prediction problem of one vehicle assembly line.

Research on Manufacturing Service Unit Modeling and Its Quantitative Assessment Method Based on Information Entropy

Ma Jun, Luo Guofu, Geng Junxiao, Lu Di

2014, 25(14):  1916-1921. 

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In order to assess the rationality of manufacturing service unit in the manufacturing service collaboration, a manufacturing service unit modeling and its quantitative assessment method were established based on information entropy theory. At first the process of manufacturing service collaboration was explained, a manufacturing service unit model was promoted. And then, based on Shannon information entropy theory, considering the correlation between information capacity of manufacturing service unit and manufacturing feature identification code, a quantitative assessment method for manufacturing service unit was established. An instance shows that the method can reduce information redundancy effectively in manufacturing services chain and optimize the manufacturing services collaboration process.

Dynamics Characteristic Analysis of Complex Rigid Frame Structure Considering Shear Deformation

E Linzhongyang, Liu Chunchuan, Li Fengming,

2014, 25(14):  1922-1925. 

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A spectral element method was used to analyze dynamics response characteristics of the complex rigid frame structure. The local dynamic stiffness matrices of straight bar and Timoshenko beam could be established, and the global dynamic stiffness matrix of the frame structures could be obtained. Comparing frame harmonic response based on spectral element method and finite element method, and calculating the natural frequencies and frequency domain results under impact load further, it shows that the spectral element method can be used effectively and accurately to analyze the dynamic response characteristics of complex frame structures, especially for the high frequency responses, and the precision and efficiency are high compared with the finite element method.

Research on Force Deformation of Microball in Contact Measurement

Li Zhibo, Huang Qiangxian, Zhao Jian, You Huanjie, Cheng Zhenying

2014, 25(14):  1926-1929. 

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As the size of microball used for micronano measurement system decreased continuously and the uncertainty of measurement in nanometer measurement should be improves constantly, the influence of deformation caused by measurement force on the uncertainty of the measurement system was becoming an issue gradually that could not be ignored. Herein, the contact model between the microball and the workpiece, and the force deformation model of microball and workpiece were built based on Hertz theory, and then the estimation method of maximum allowable measurement force and the force deformation were given. Microballs made of three kinds of material, which were used for micronano CMM were selected as reference, the maximum allowable measurement force and the deformation were  estimated. The results show that the errors of force deformation should not to be ignored and needs to be paid more attention in contact nanomeasurement.

Dynamic Modeling of MSI Based on a Hybrid Approach and Experimental Verification

Song Chunsheng, Zhang Jinguang, Zhang Jianguo

2014, 25(14):  1929-1934. 

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MSI, as an active isolation actuator, had advantages including noncontact,high response frequency, high reliability and long lifespan. However, its potential was not fully explored due to the nonlinear and hysteretic behavior in dynamic environments, and there was limited research work in the area. This paper proposed a new ANNbased approach to model the dynamics of MSI. A HA was developed to train the ANN to improve the model accuracy. Results clearly show that the ANN model with the HA approach outperforms the back propagation(BP) approach and modified genetic algorithm(MGA) approach. An experimental platform was developed to test the performance of the magnetic suspension vibration isolation system and the proposed modeling approach. The output force response of the active and passive system under the same excitation are measured. The results show that the active with proposed model control system has much better performance in vibration isolation.

Rapid Reverse Modeling of Batched Complex Blanks

Wang Haizhou, Zhang Liyan, Zhou Liangming, Liu Shenglan

2014, 25(14):  1935-1940. 

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The batched complex blanks with same structure and certain deviations in geometry often needed to be reconstructed. The repeated process wasted a lot of labors and extended the production cycle. An efficient reconstruction method was proposed based on the structural template and the reverse design table. Firstly, the feature of the blank's structure was analyzed. A template representing the structure features, as well as a reverse design table based on open knowledge representation, was established. Secondly, the elements in the template and the steps in the design table were utilized to segment the cloud points automatically. Thirdly, different types of surface were reversely reconstructed and post processed orderly. The experimental results validate the method's high efficiency.

Optimization Approach of Cutting Parameters in Parallel NC Turnings with Two Cutters

Xie Shutong, Guo Yinbiao

2014, 25(14):  1941-1946. 

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To optimize cutting parameters in parallel turnings so as to reduce unit production cost(UC), a hybrid optimization approach(ACOEAS) was proposed, which combined ACO with EAS.Taking minimization of the UC as objective function, the cutting parameters in both rough and finish machining as decision variables, the mathematical model of cutting parameters in parallel turnings was established. And then according to the characteristics of turning operations, the optimization problem of cutting parameters was dived into several subproblems. The corresponding theoretical lower bounds on UC were derived, which were effective to decrease the complexity of the problem. Simulation results show that the proposed ACOEAS can achieve optimal cutting parameters with high efficiency in order to save UC.

Position/Pressure Switching Control Based on Velocity Damping

Long Zhili, Yu Xinlu, Zhu Chao

2014, 25(14):  1946-1950,1955. 

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Stable and fast switching between displacement and pressure will directly ect precision and velocity of automated equipment. To solve the shortage of direct switching between displacement and pressure, switching control between displacement and pressure was proposed for motion switching of automated equipment, which was based on the velocity damping. The damping was changed with the parameters of velocity ring. So this control can realize stable switching between displacement and pressure. This control can suppress vibration in the process of pressure
loading. Compared to direct switching control, the proposed switching control becomes more accurate and faster. The measurement data shows that the mplitude of forces of fluctuations are within the range of ±0.3N.

An Identifying Structural Parameter Technique Based on Galerkin Mappingreduced Basis Method

Zhang Zheng, Liu Jie

2014, 25(14):  1951-1955. 

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An effective parameter identification technique  which was based on the Galerkin mappingreduced basis method was proposed for dealing with parameterized structural problems. The investigated structure was firstly discretized by the finite element method. And then using the angle of vector subspace, the nonsingular monitoring basis matrix and corresponding whole basis matrix were constructed in the positions of monitoring points. Subsequently, the identification model of structural parameters in the reduced basis model was constructed by minimizing discrete L2 norm of vector. Finally, the parameters of original problem were identified using the corresponding trust region optimization technique. An example herein demonstrates the presented method has higher computational accuracy and total efficiency than that of the existing classical methods.

Mechanism Analysis and Experimental Validation of Dissimilarity of Mechanical Thermal Deformation

Miao Enming, Xu Zhishang, Zhou Xiaoshuai, Ni Yang

2014, 25(14):  1956-1959,1966. 

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Building a nanoatomic model of cube aluminum materials at microscopic level and solving it by using the molecular statics theory and algorithms with the modified Morse potential, the paper demonstrated thermal deformation mechanism of part scientifically and gave the results of macroscopic thermal deformation experiments. The microscopic analysis and macroscopic experiments prove the existence of dissimilarity of mechanical part thermal deformation, making up defects of demonstrating them only by macroscopic experiments and improving the mechanical part thermal deformation theory. Meanwhile, the molecular statics theory was introduced into research on the mechanism of thermal expansion, which expands a new research way of mechanical thermal deformation theory.

Study on Surface Undercut of Laser Welding of Thick Plate with 10kW Class Fiber Laser

Chen Genyu, Zhou Yu, Zhang Mingjun, Li Shichun

2014, 25(14):  1960-1966. 

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Due to surface undercut in the process of welding of SUS 304 stainless steel plate with 12mm thickness using high power fiber laser, the flow of molten pool was captured by a highspeed camera based on “sandwich” method. The influences of the welding orientations, welding speed and the root hump on the surface undercut were discussed, and the formation causes of the surface undercut were investigated. The results show that the average depth decreases gradually with varying the welding orientations from horizontal orientation welding to the vertical orientation welding. Moreover, as the welding speed becoming smaller, the size of the “shelf” on the keyhole front wall increases and the undercut becomes deeper. With generation of the root hump, the top molten pool lacks the liquid metal resulting in surface undercut.

Numerical Analysis of Hydroforming Assembly of Stator and Can with Empty Groove

Liu Huahan, Jiang Wei

2014, 25(14):  1967-1972. 

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Numerical simulations were conducted to study the hydro forming assembly of the AP1000 stator components. Firstly, five different loading paths were suggested to study the assembly effects. A suitable loading path was obtained based on the analyses of  the formability. Then the relationships between the bulge ability and the internal pressure with the change of the initial clearance were analyzed. Finally, the effects of the coefficient of friction on the assembly process were examined. The results show that the simulation method benefits the determination of assembly process and the prediction of assembly effects, and a better assembly result can be obtained by a proper coefficient of friction.

Construction Machinery Adaptive Electronic Differential Control Based on Field Weakening Control

Bian Yongming, Jiang Jia, Yang Libin

2014, 25(14):  1972-1977. 

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The traditional wheel construction machinery used mechanical differential to realize differential, while the differential function of wheel electric driving system mainly realized by the electronic differential control technology. Common electronic differential control strategies were analyzed and the adaptive electronic differential technology based on field weakening control algorithm was proposed. After modeling the wheel electric driving loader, working condition of turning and going straight with different rolling radius were simulated. The steering experiments of wheel electric driving loader were taken under the conditions of light loading and heavy loading. It is shown that the left and right electric wheels can realize adaptive differential and smooth steering by using field weakening control algorithm.

Integrated Control of Active Suspension System and Active Roll Stabilizer

Zhou Bing, Lü Xuning, Fan Lu, Zhang Wenchao

2014, 25(14):  1978-1983. 

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A dynamics model of a full vehicle which equipped the active suspension system and active roll stabilizer was set up to improve ride performance and handling stability of the vehicle. Also active suspension and active roll stabilizer controllers were designed based on the coupling relationship between the two systems. The PID integrated control strategy was designed based on PID control and linear control. The vehicle in the steering working situation was simulated with MATLAB/Simulink. The simulation results show the effectiveness of proposed integrated control strategy to improve handling stability and ride comfort.

Intelligent Steering Control Strategy of EV Based on Improved Preview Following Algorithm

Huang Xichang, Zong Zhijian

2014, 25(14):  1984-1987. 

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An intelligent steering control strategy of EV was described based on an improved preview following algorithm driver model. A new previewpoint searching algorithm was proposed to ensure that the previewpoint fell on the expected track and availed on the large curvature road. The steering control strategies considered the impact of the steadystate response to improve the dynamics performance of the EV. Combined with power model and track model of EV, the steering control strategy was stimulated by Dymola that is a multidomain modeling and simulating software. The results indicate that the EV with application of the strategy performs a high level of accuracy on the target tracking following.