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Table of Content

    26 August 2014, Volume 25 Issue 16
    Applications of KVPMCD Based on Kriging Function in Rolling Bearing Fault Diagnosis
    Yang Yu, Pan Haiyang, Li Jie, Cheng Junsheng
    2014, 25(16):  2131-2136. 
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    The fault diagnosis of rolling bearings was a pattern recognition problem essentially, variable predictive model-based class discriminate(VPMCD) was a new pattern recognition method, in essence, through the inner relations among these features, a mathematic predication model that could be established and used to predict the features of those diagnosed bearings and thus to achieve the goal of pattern recognition. But the VPMCD classification method could only use the regression model to predict, so it would reduce the prediction accuracy when the relation of features was complicated. Aiming at this defect, a KVPMCD pattern recognition method was presented. Kriging model was composed of regression model and correlation model, and the latter was local deviation which was created on the basis of global model, and it could reveal the spatial correlation with features exactly, so as to make up for the shortcomings of simple regression model in the original VPMCD.The analysis results of the UCI standard data and the experimental data of rolling bearing show that compared to the original VPMCD, KVPMCD pattern recognition method can identify the working states and fault types of rolling bearings effectively.

    Research on Control Method of Low Voltage Ride Through for Hydraulic Wind Turbine
    Kong Xiangdong, Ai Chao, Yan Guishan, Lou Xiaoxiang
    2014, 25(16):  2137-2143. 
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    Taking a hydraulic wind turbine as the research object,a LVRT control method was proposed based on the direct control of the swing angle of the variable motor aiming at rapid adjustment of the hydraulic system power requirements. The control target was that the power frequency speed of generator was stabile and the hydraulic system transient adjustment time was short. Using 30kV·A hydraulic wind turbine simulation platform as the simulation and experimental platform, the control method presented for LVRT was researched. Simulation analysis and experimental results show that the LVRT control method based on the direct control of the swing angle of the variable motor has better low voltage ride control.

    Experimental  Study  on Tribological Properties of Textured Cemented Carbide Made  by  Diamond Scratching
    Zhang Gaofeng, Long Shishan, Tang Aimin, Zhang Xu, Zhang Bowen
    2014, 25(16):  2143-2148. 
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    Surface micro-textured cemented carbide's(YG6) with scratch width 10~50μm was prepared by using a diamond indenter that had  tip radius 10μm and tip angle  120°, and the tribological properties of the textured surface was tested by ball-on disk method,and  friction force and coefficient of friction were measured on line. After friction test, the surface morphologies of the samples were observed by using ultra-depth field optical microscopy and scanning electron microscope(SEM). Results show that diamond scratching method is suitable for fabricating micro-texture on cemented carbide, and surface texturing is helpful for reducing friction coefficient, especially when the mico-texture direction is perpendicular to the friction direction.

    General Class Ⅱ Synthesis of Disc Cam Mechanism with Roller Follower Moving in Planar General Motion
    Chang Yong, Lin Rongfu, Li Yanping
    2014, 25(16):  2149-2158. 
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    A problem of the deep general class Ⅱ synthesis was proposed,which expanded the  “object space”  and  “solution  space” of the mechanical synthesis.By introducing the offset e,a set of solving analytical formulas and a series of analytical criterion of the solution existence were obtained.The existence and physical meanings of a couple of ridge points and a new ridge were revealed, and the solving method of the “bottom feature point” was presented. The new concepts and analytic expressions of “sub inferior solution/sub non-inferior solution” were put forward. By selecting the mechanical figure and coordinate system as the background,the family of discrete curves facing “super two-dimensional class Ⅱ synthesis  problem”—{C#2}em,{C#1}em,{C**}em,r0min-e,r0max-e,r0opt-e  and  [α]**-e  were constructed. The existence and solving method of the “global optimal solution” were proposed. Lastly, it is demonstrated that the offset mechanism has solutions while the non-offset mechanism does not have, the offset mechanism has the superior solutions while the non-offset mechanism has average solutions by presented two synthesis examples.

    Applications of Quantum BP Neural Network in Engine Fault Diagnosis
    Li Sheng, Zhang Peilin, Li Bing, Li Chen
    2014, 25(16):  2159-2163. 
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    In order to solve the problem of slow convergence speed and low classification accuracy in common BP neural network(CBPN), a model of quantum BP neural network(QBPN) was proposed. Quantum computation was introduced into CBPN. The structure of QBPN contained input layer, hidden layer and output layer, where input and transfer function were represented by quantum bit, and the output was real value. Firstly, the real-valued training samples were transformed into quantum training samples, which was as the input. Then, with transfer function, the quantum weights were calculated, and the network parameters were updated to achieve the required result. Finally, the trained network  was used for fault diagnosis, and the result was output in real value. The proposed method was applied in fault diagnosis of engine. The results indicate that, compared with CBPN, QBPN has great advantages of convergence speed, classification accuracy and executing time.

    Control Strategy and Implemention of a Quick Pressure Device for Underwater Escape
    Liu Jianguo, Li Weijia, Cao Heyun
    2014, 25(16):  2163-2166. 
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    A fast compression experimental system by water injection was proposed by means of analyzing the working characteristics of the fast floating escape from deep sea, where fuzzy control was applied. The fuzzy control strategy was chosen by analyzing the influences of pneumatic control valve with serious hysteresis and nonlinearity of the control system based on AMEsim  simulation platform. A precise control of the fast compression was process by water injection was achieved by building onshore debugging platform, and the feasibility of fast compression was proved by  water injection to achieve fast floating escape from deep sea.

    Research on Fatigue Life Prediction Methodof for Arm Structure of Hydraulic Excavator
    Tong Shuiguang, Wang Xiangbing, We Chao, Zhang Shuai
    2014, 25(16):  2167-2172. 
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    The fatigue life for arm structure of hydraulic excavator was influenced by many uncertain factors because of the complex impact loads were applied to it. Firstly, the Miner's rule was used, and the fatigue life of work device of hydraulic excavator was predicted based on experimental load spectrum and the finite element method. Then the internal consistency of the changing process of structure fatigue life and the grey theory prediction model was researched, the grey GM model of fatigue life prediction of hydraulic excavator's work device was established, the fatigue life of  hydraulic excavator's arm structure was predicted by using two forms of GM model, the linear model of GM(1,1) and the power model of GM(1,1) respectively. Three kinds of prediction methods, the Miner's rule, the linear model of  GM(1,1) and the power model of GM(1,1) were analyzed and compared, it is shown that the predicted results of three methods are basically identical, the error of gray system model is decreased obviously compared with the model of Miner's rule, and the nonlinear power model has higher predictionprecision. Because the nonlinear factors were considered in gray power model of GM(1,1), the gray power model of GM(1,1) is more suitable for the structure fatigue life prediction of hydraulic excavator's work device.

    Damping Characteristics of Thin Cantilever Plate Structure Identified by Frequency Bandwidth Method of Base Excitation
    Li Hui, Sun Wei, Xu Kai, Han Qingkai
    2014, 25(16):  2173-2177,2183. 
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    For some small size structures required to obtain the damping parameters precisely, damping identification method of half-power bandwidth by the dynamic ping method was often unsatisfactory. Herein, on the basis of confirming the principal formulas of the damping identification, a new test method was proposed to identify damping parameters in the frequency domain by sweep excitation through vibration shaker exciter, which was on the improvement of classic half-power bandwidth method and was named as FBM. Moreover, this new method was subdivided into the following two damping identification methods, i.e. direct response method and response with a reference signal(RSFBM)  in frequency domain. And their test and identification process were illustrated respectively by practical damping measurement which was carried out on the research object of small size and thin cantilever plate. At last,the detailed influences on damping results were discussed and analyzed in the aspects of the sweep rate, sweep direction and the two different identification methods. This study can provide an important reference to experimental damping test in engineering field.

    Rotation Angle Solution for Post-processing of Five-axis Machine Tools with Infinite Rotating C-axis Worktable
    Jiang Lei, Li Zhuang, Li Xiangbiao, Zhou Liangming, Duan Changde, Ding Guofu
    2014, 25(16):  2178-2183. 
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    The stroke of C-axis rotary worktable for five-axis machine tool could be extended from limited angle range to n×360°, however the performance of machine tools could be restricted due to the limited rotation angles solution of common post-processing calculation methods. Herein,a kinematics equation of rotation axes was established based on multi-body system theory firstly. And the calculation method of rotation angle was improved by defining “the minimum movement circle”. Moreover, the calculation flow was determined, by which the rotating continuity of C-axis worktable was improved effectively. Finally, the feasibility and effectiveness of the proposed method were verified by some simulation experiment,about the post-processing calculation method.

    Analysis of Carbon Emission in Gear Dry Machining Process for Green Manufacturing
    Li Xianguang, Yang Yong, Li Congbo, Chen Peng, Cao Huajun
    2014, 25(16):  2184-2190. 
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    To study the characteristics of carbon emission of gear dry machining process for green manufacturing, the materials, energy consumption, waste treatment and carbon emission were analyzed. The boundary conditions of carbon emission were proposed for the gear machining process, and a calculation model for carbon emission was constructed. According to the data of a manufacturing enterprise, the carbon emission of gear dry and wet machining process were calculated. The contrast analyses show that the carbon emission of gear dry machining process is 55.69% and lower than wet cutting, and the carbon emission value of waste treatment process in dry cutting is 15.57% and lower than wet cutting. The analyses validate that the energy consumption and cost of dry machining are relatively lower, and the high-speed dry-cutting gear technology will become the main trend of future development of gear manufacturing industries.

    A Hybrid Sequential Heuristic Procedure to One-dimensional CSP
    Cheng Hao, Liu Xinbao, Fang Chang
    2014, 25(16):  2191-2195,2203. 
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    This paper proposed an improved hybrid sequential heuristic procedure for one-dimension CSP.The algorithm modified the subset selection strategy of original sequential heuristic procedure and avoided the ending condition in the limited time with width search algorithm,and could change the parameters according to the users' maximum time patience dynamically.Finally C# was used to realize the algorithm.the results show the algorithm is effective.This algorithm were used in Ma'anshan Steel Corp,wheel company official for more than two years,and increases  the cutting rate 4%.

    Modeling and Optimization of Process-assembly-type Flow-shop Scheduling Problem with Energy Saving
    Zhao Yanwei, Zhang Liping, Zhang Jingling, Wang Wanliang, Wang Haiyan
    2014, 25(16):  2196-2203. 
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    To solve the process-assembly-type flow-shop scheduling problem with energy saving, a flow-shop scheduling model of energy saving was established. The assembly line was as a special process line with special restraint in this model. Then the workpiece process,assemble process, assemble component process, process set-up time all were considered. This paper researched about the simple and complex scheduling problem with assembly constraint, adopted hybrid evolution algorithm to solve the scheduling plan with lowest energy consumption, and  then contrasted to adaptive differential algorithms. It proves that the hybrid difference evolution algorithm is more effective for solving the problems.

    A Surface Feature-Preserving Point Cloud Simplification Method for Aviation Blades
    Li Qidong, Li Wenlong, Zhou Liping
    2014, 25(16):  2204-2212. 
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    A novel point cloud simplification method was proposed to avoid insufficient sampling in aviation thin-walled blades' edge regions with high curvature feature and sparse regions with fewer points based on re-clustering strategy. To establish the geometric deviation between the original and simplified point cloud, point-surface distance function was  defined to distinguish curvature information based on moving least-square method. The distance function was used to re-cluster the regions with high curvature feature to realize adaptive feature-preserving process. Moreover, the regions with sparse points was distinguished and subdivided to ensure sufficient points in sparse regions. Comparing with uniform sampling method and hierarchical clustering method, the method presented above has higher geometric precision for point-sampled blade surfaces or other complex surface point cloud, such as fan disk.

    Research on Easy Disassembly and Recycling Design System for Household Electrical Appliances
    Liu Zhifeng, Cheng Huanbo, Yuan He
    2014, 25(16):  2213-2218. 
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    TRIZ conflict resolution principle, material-field analysis principle and recycling conflict analysis principle were used to carry out easy disassembly and recycling design system for household electrical appliances.Design process was proposed for easy disassembly and recycling.The mapping relationships between easy disassembly and recycling design proposal  were  established.Aiming at the physical conflict and technology conflict of easy disassembly and recycling design, the invention principle or standard solution for this conflict could be searched, or search for the typical easy disassembly and recycling design proposal through keywords would guide the designer to develop green household electrical appliances rapidly. Finally, evaluation of easy disassembly and recycling design was obtained. VB. NET was used to realize software compiling,and friendly interface, user-convenient easy disassembly and recycling design software system were developed. The software was used in refrigerator and air conditioning and other refrigeration products design process, which provides technical support for the enterprises to realize the green household electrical appliances product development.

    Rotor Fault Diagnosis Method Based on Orthogonal Locality Preserving Projection
    Sun Bin, Liu Liyuan, Lei Wei
    2014, 25(16):  2219-2224. 
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    In order to improve the classification performance of fault pattern recognition,this paper proposes a local orthogonal locality preserving projection(OLPP) algorithm based on orthogonal manifold feature extraction method. For high dimensional nonlinear data, it can effectively extract the low dimensional manifold feature vector, and will not change the intrinsic attributes of data. Construct a high-dimensional symptom matrix with the vibration signal of the rotor, the orthogonal locality preserving projection was used to reduce the dimension of this high dimension matrix, extract the low dimensional feature vector matrix, mapping in the visual space, this can achieve the result of fault classification effectively, enhance the accuracy in  fault  diagnose. Finally, through experiment and data dimension reduction simulation process shows that the orthogonal locality preserving projection is effective and feasible.

    Thermal Error Modeling of NC Machine Tool Using Neural Fuzzy Control Theory
    Yu Zhimin, Liu Zijian, Ai Yandi, Xiong Min
    2014, 25(16):  2225-2231. 
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    A modeling method of fuzzy neural network based on neural fuzzy control theory was applied in thermal error  modeling of NC machine tool and the structure and modeling principle of fuzzy neural network on thermal errors was discussed. The experiment on spindle head of large NC gantry guide grinder was conducted and two independent sets of  experimental data were obtained by measuring the temperature of spindle head and the thermal error of spindle with non-contact infrared thermometer and dial gauge, one was used to establish thermal error fuzzy neural network prediction model of  spindle head  and the other was used to validate the model. The test results show that fuzzy neural network model has high prediction accuracy and good generalization. Compared with radial basis gunction(RBF) neural network modeling method, fuzzy neural network modeling method has better modeling efficiency, robustness and predict performance.

    Research on Hot Embossing Process of Microfluidic Substrates with Both Convex and Concave Microstructures
    Zhang Zongbo, Wu Baogui, He Qingqiang, Luo Yi, Wang Xiaodong, Wang Liding
    2014, 25(16):  2231-2234,2239. 
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    Hot embossing process of the devices with both concave microchannel and convex micro energy director for ultrasonic bonding was researched. Based on the constitutive relation and temperature-depending mechanical properties of the material, commercial software was redeveloped. FEM was employed to simulate the embossing processes with different embossing temperatures. The influences of temperature and holding time on replication accuracy was analyzed with strictly defined embossing force. And the processing parameters were optimized. A silicon mold fabricated by multi-step lithography technology and two times of wet-etching processes was used in the hot embossing experiment. The experiments agree well with the simulation results.

    A Global-Parameter Optimal Design Method for Serial Manipulators
    Xiao Yongfei, Wang Xuelin, Zhang Fuhai, Chen Tie, Fu Yili
    2014, 25(16):  2235-2239. 
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    To the problems that nonlinear physical-parameter function of serial manipulators led to local optimization, a global optimal method based on linear matrix inequality was proposed. Acording to the ideas of co-work of mechanism and control system, the dynamic characteristics of prescript action were analyzed using minimum energy law by transfering  the solution of nonlinear dynamic function to optimization problems of linear matrix inequality. Further, the gloal optimal physical parameters, such as the mass, the geometirc dimenstion, the moment of inertia, were achieved. A 4-DOF heavy-load robot was designed by this method, and the operating results verify the effectiveness of the proposed method.

    Grinding Performance of a New Diamond Grinding Wheels in Machining Al2O3  Ceramic
    Wu Qiaoping, Deng Zhaohui, Zhao Qiancheng, Pan Zhan, Kang Huimin, Wan Linl
    2014, 25(16):  2240-2246. 
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    A new diamond grinding wheel was prepared by powder injection molding and vacuum brazing, the new diamond wheel had a larger number of cutting edges which were artificially ordered so as to have big chip storage space, and it realized strong adhesion between diamonds and brazing alloy due to vacuum brazing. The paper discussed the grinding performance of the new diamond wheel in machining Al2O3 ceramic. The experimental results indicate that the quality of the machined work-piece surface is better than that machined by the conventional resin bond diamond wheel, the  surface roughness is as 0.68μm when the feed speed is as 40mm/s and the depth of grinding is as 40μm, and the forces decreases by 12%~17% in compassion with conventional resin bond diamond wheel, and grinding temperature is reduced 80~120℃.

    Transient Data Acquisition and Diagnosis System of SCR for Diesel Engine
    Hu Mingjiang, Luo Congshuang, Wang Zhong
    2014, 25(16):  2247-2252. 
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    Based on the transient characteristic of urea-SCR system, it was developed on the test and diagnostic system on transient parameters of SCR system for diesel engine. The programs on the interface, demarcate and diagnosis could be conveniently compiled by DASYLab software, it could be carried out on the measured and diagnostic functions by the tracking and diagnostic procedure, such as, the transient parameters were collected, storaged, diagnosed and displayed at the same time in SCR system. According to the cycle regulations of the diesel engine transient test, these measured and diagnostic tests were carried out on the NOx conversion efficiency, the amount of the urea dosing and the NH3  leakage of SCR system. The testing results show that compared with standard AVL testing system, the dynamic maximal error of the designed system is as 2.05%, the dynamic average error is as 0.82%, and the diagnostic accuracy rate can also reach 98.6%, which can meet the needs of the dynamic data acquisition and diagnosis of SCR system for diesel engine greatly.

    Research on Parametric Modeling and Mechanical Properties of Lightweight Lattice Structures
    Zhong Liangwei, Li Xiaowei, Hu Shougen
    2014, 25(16):  2253-2261. 
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    To address the difficulty of designing lattice material structures, this paper established cellular structure mathematical model derived from the cuboid space, and built the unit cell and system on specimen's parametric modeling and its mechanical properties. The FEA method was introduced to analyze the mechanical properties of these five typical unit cells when stressed, bended,twisted or modal with the same shape, size, mass and loading force by changing their cellular sizes and quantity or pillar section. The findings of the comparative study data of the mechanics performance obtained for various unit cells provide the support for the lattice material design under disparate loading conditions. The way is demonstrated to be correctness and reliability with the results.

    Research on Ideal Steering Wheel Effort Characteristics of Driver
    Ren Xianan, Deng Zhaoxiang,
    2014, 25(16):  2261-2265. 
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    The ideal steering wheel effort characteristics of driver were analyzed and a model was put forward to describe the characteristics in the working conditions of steady state steering. The ideal steering wheel effort model for drivers in southwest China was established based on the road test results of three different vehicles. The results show: ideal steering wheel effort of driver is an increasing function of steering wheel angle or vehicle lateral acceleration when driving at a certain speed, but the increasing rate is become slower as steering wheel angle or vehicle lateral acceleration become larger. Under the condition of the same steering wheel angle or lateral acceleration, ideal steering wheel effort of driver is almost linearly proportional to the vehicle speed. When driving on the same road, driver's ideal steering wheel effort is barely related to the vehicle type if these vehicles' volume and weight are close.

    Design and Study on Sled Collision Test of Children Occupant Restraint System
    Bai Zhonghao, Wang Yulong, Lu Jing
    2014, 25(16):  2266-2271. 
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    In order to satisfy the acceleration interval requirements when a dynamic performance test of CRS was conducted, a method of reproducing crash acceleration using thin-walled circular tubes with different lengths, diameters and wall thicknesses was introduced. A finite element model of sled and energy absorption tube was established by LS-DYNA. The combination of parameters of tubes satisfying frontal or rear crash acceleration interval requirements were abtained by simulation analysis based on the established model and sled collision test were conducted to verify effectiveness and accuracy of the model. Then the head and chest injury mechanism of Q6 children dummy was analyzed and the head center trajectory was got through the pixel analysis. Finally, the improvement suggestions were introduced.