Table of Content

10 June 2014, Volume 25 Issue 11

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Kinematic Analysis of an Inverted Planetary Roller Screw Considering Roller Pitch Circle Mismatch

Ma Shangjun, Liu Geng, Tong Ruiting, Zhang Wenjie

2014, 25(11):  1421-1426. 

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Taking an inverted planetary roller screw as the research object, the kinematic models were developed to investigate axial displacement and slip velocity of the roller relative to the screw, which was caused by a pitch circle mismatch between the roller thread and the roller gear. First, the calculation formulas of the angle of slip, axial displacement and slip velocity of the roller relative to the screw were presented, and the effects of roller displacement on the overall lead and slip velocity of the mechanism were analyzed. Then, an inverted planetary roller screw was selected as an example, and the pitch circle mismatch values due to contact deformation were derived. Furthermore, the axial displacement and slip velocity of the roller relative to the screw were calculated by using the formulas respectively. The results show that the roller displacement does not affect the lead of the overall system, the slip must occur at the nut-roller interface, and slip velocity is decreased by decreasing the pitch mismatch values at the screw-roller interface effectively.

Effects of Thermal Boundary Conditions on Thermohydrodynamic Lubrication Analysis of Plain Journal Bearing

Zhang Zhenshan, Yang Yumin, Dai Xudong, Xie Youbai

2014, 25(11):  1427-1432. 

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A THD model of plain journal bearings was proposed herein. This model involved the synthetic solution of the generalized Reynolds equation, three-dimensional energy equation, and heat conduction equations of the solids. On the basis of that, series of results were provided to examine the effects of thermal boundary conditions. The results show the thermal boundary conditions have considerable effects on the THD analysis of plain journal bearings. Therefore, it is necessary to choose the thermal boundary conditions according to the actual operating conditions, so as to obtain reliable calculating results.

Condition Monitoring of Aero-engine Based on PCA and LDA

Zhou Yuan, Zuo Hongfu

2014, 25(11):  1433-1437. 

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This paper proposed an approach for aero-engine condition monitoring by sensors data based on PCA and LDA. The failure features of sensors data were re-extracted via PCA and LDA, and the engine conditions were classified by the nearest neighbor algorithm. The experiments were conducted on the 2008 IEEE PHM challenge data, and the proposed approach was compared with a PCA based classification method and a DBN based  classification method. The results show that the proposed method exhibits a higher recognition accuracy with simpler structure which is practicable and efficient to engineering apllications.

Research on Fingertip Output Force Characteristics of 3-DOF Finger Based on FPA

Qian Shaoming, Wang zhiheng, Yang Qinghua

2014, 25(11):  1438-1442. 

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A 3-DOF finger consisted of three flexible pneumatic bending joints, the bending joint was driven directly by a FPA, the joint torque was decided by the value of the compressed air in the FPA. The kinematics and Jacobin matrix of the finger were educed herein. The statics of the finger was analyzed, and then static model about fingertip force and the value of the pressured air in FPA was built. Experiments were carried out to verify the statics model. It is concluded from theoretical and experimental results that the experimental force value matches with the simulation force value basically.

Hybrid Excavator Shafting Torsional Vibration Characteristics

Huang Zhonghua, Xie Ya, Deng Yi

2014, 25(11):  1443-1446. 

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Hybrid excavator shafting finite element analysis model was established and shafting first 5 order modals were calculated. Modal calculation results show that hybrid excavator shafting 1 order modal frequency is decreased by 270Hz compared with traditional excavator shafting. Modal shapes of first 2 order modal are torsional vibration. Hybrid excavator shafting dynamic simulation model was established to obtain shafting torsional vibration characteristics. Simulation results show that shafting torsional vibration is periodic. Torsional angle amplitude is about ±0.003°. There is a peak in torsional angle frequency spectrum. The peak frequency is about 48.9Hz. Hybrid excavator shafting torsional vibration test table was established and torsional vibration testing with different rotate speeds were carried out. Experimental results show that shafting maximum torsional angle is about 0.003° when shafting speed is greater than 1100r/min. Shafting maximum torsional angle is decreased with rotate speed increasing when shafting speed is less than 1100r/min. Shafting maximum torsional angle is about 0.007° when shafting speed is 896r/min.

Mode Analysis and Design of Maglev Flexible Rotor with ANSYS

Li Hongwei, Yu Wentao, Liu Shuqin

2014, 25(11):  1447-1452,1459. 

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Based on an experimental maglev flexible rotor, a rotor modal design method was discussed by employing ANSYS software. The influence of the bearing stiffness on the rotor modal frequency and modal shape was analyzed. Upon the above work, the setting principle of the bearing stiffness was studied for the maglev flexible rotor, which will pass across its critical speeds. And the proper range of the bearing stiffness for the experimental maglev flexible rotor was obtained. The study results include that one influence factor on the controllability and observability of rotor mode is the ratio of the length sum of the radial magnetic bearing rotor and rotor displacement detection ring to the total length of the rotor; the bearing stiffness influences the rotor modal frequencies and the rotor modal shapes. And the very high bearing stiffness can worsen the controllability and observability of modes severely, and even can cause the maglev rotor unstable when passing across critical speeds.

Study on Applications of Secondary Regulation Technology in Test Bench Loading System

Ma Dengcheng, Yang Shimin, Ma Denghui, Jiang Xiaoming

2014, 25(11):  1453-1459. 

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A mathematical model of the loading system secondary element control system was established through theoretical analysis, and the dynamic simulation analysis was conducted by using MATLAB and SIMULINK software. The simulation result shows that: the adjusting time is as 0.068s, rise time is as 0.026s, and tracking frequency is as 6Hz the input signal has high response accuracy. The experimental results show that: when the step load with load torque 360N·m and 222N·m, the rise time of system response is equal (about 0.18s), adjusting time is equal (about 0.4s). When sinusoidal load with frequency of 1~6Hz is loaded, the maximum error of average is less than 1.24%, the amplitude error is excess 6% when 3Hz sine wave load is loaded, and is less than 6% under other frequencies.When the actual impact load with low frequency is loaded, better tracking performance and fast response are obtained. It shows that, the loading system performance is stability, and has good dynamic performance and control characteristics, can meet the dynamic performance of hydraulic chassis needs.

Reliability Modeling and Analysis of Assembly Process of Products Based on GGSPN

Zhang Genbao, Qian Baoming, Liu Jian, Li Dongying, Peng Lu

2014, 25(11):  1460-1465. 

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Aiming at the assembly step of products, the paper put forward a modeling method based on GGSPN focusing on the assembly reliability of products. First of all, the GGSPN model during the assembly process of products was set up before which the assembly relation analysis among various assembly steps was done. Secondly, the simplication of the GGSPN model was realized based on the basic stochastic Petri net model and the equivalenced-performance equation. Thirdly, according to the uncertain lack-of-information problems of failure information during the assembly process, the paper employed grey numbers into the generalized stochastic Petri net model to optimize the vicissitude stimulating rate. Moreover, the stable-state probability represented by grey numbers and the whitenization were worked out directing at the set-up reliability model of the assembly process of products. After the reliability analysis during the assembly process, the improved measures of reliability control were carried out. In the end, the feasibility of the mentioned method was proved by the assembly process of a gear oil pump as example.

Research on Implementation Postponement Strategy Production System Simulation Based on HTCPN

Luo Jianqiang, Xuan Juanli, Ma Hanwu

2014, 25(11):  1466-1472. 

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Combined the advantages of HTCPN in modeling for production system, the postponement and non postponement production system model were constructed, then postponement production system was investigated relative to the non postponement production system, which had advantages in inventory, meeting customers' individual requirements and so on. For getting customization information accurately and timely, information interaction platforms among manufacturers and their customers were embedded into postponement production system model, and simulated the models by using CPN Tools.The results prove that customers' real-time participation can improve the customized product process, shorten the average customer waiting time, improve the capacity of customization production in enterprises, and finally realize ascension of customer value.

Remanufacturing Quality Optimization Method of Complex Mechanical Products Based on Assembly Deviation Degree

Liu Mingzhou, Sun Zhijun, Ge Maogen, Wang Xiaoqiao, Wang Qiang

2014, 25(11):  1473-1477,1497. 

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In order to improve reliability and stability of remanufacturing quality for complex mechanical products, a remanufacturing quality optimization method of complex mechanical products was presented based on the assembly deviation degree. Considering the reassembly process variation and transmission mechanism, a reassembly process deviation function was set up. By dividing the relevant quality control domain, the conditions and methods of remanufacturing quality were described based on the assembly deviation degree, and the simulated annealing genetic algorithm was used to solve the assembly deviation degree on-line optimization model. Finally, the reassembly process of main gear demonstrates the feasibility and effectiveness.

An Investigation on Quantitative Analysis of Carbon Footprint in Centreless Grinding Process and Its Key Factors

Guo Dengyue, Cheng Kai, Ding Hui, Yan Jihong, Ma Yunhui

2014, 25(11):  1478-1485. 

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To accurately quantify carbon dioxide emission in manufacturing process is a prerequisite for low-carbon manufacturing. Grinding is a widely used as precision machining method, however, it is also a less energy-efficient and environment unfriendly processing method consuming large amount of cutting fluid and generating high cutting heat compared with others. The paper identified key factors influencing carbon dioxide emission during grinding process using axiomatic design method. Considering resource utilization, energy consumption and waste generation impacting on carbon dioxide emission, the ERWC(energy,resource,waste,carbon) carbon dioxide emission quantitative analysis model of the entire grinding process with roughing, finishing and spark-out stages was developed. Mearsurement experiments were done to collect data needed and computational analysis on both ERWC model and its key factors was done with MATLAB.

Model for Engineering Change Information and Control for Change Process

Lü Shengping, Qiao Lihong

2014, 25(11):  1486-1492. 

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A unified model for the description and storage of engineering change information was established. Then, the extraction method for change information view and correlation manipulation algorithm were proposed. In order to ensure the consistency and accuracy of engineering change information between different systems, the object document of change information view was built based on XML Schema; meanwhile, the service-oriented object mapping mechanism for change information view was established. The combined push-pull mechanism based on workflow and service-request was constructed. Finally, the unified model and control mechanism was verified with an instance. This research provides an alternative method for the management of engineering change information.

Rolling Bearing Fault Diagnosis Method Based on OC-VPMCD and ITD

Cheng Junsheng, Ma Xingwei, Li Xuejun, Yang Yu

2014, 25(11):  1492-1497. 

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Variable predictive model based class discriminate (VPMCD) is a way to pattern recognitions. It made full use of the inner relations among characteristic values extracted from those original data to recognize models and classified the faults by minimum prediction error sum of squares value. Based on that, the paper proposed a new one-class classification method—OC-VPMCD and combined OC-VPMCD with ITD and applied into the rolling bear fault diagnosis. Firstly, rolling bearing vibration signals would be adaptively decomposed by ITD and the permutation entropy of proper rotations (PR) which contain the main fault information would be extracted as characteristic values. Secondly, OC-VPMCD classifier would be trained and determined the prediction error sum of squares threshold value. Finally, the OC-VPMCD classifier would be used to complete pattern recognitions; according to the pattern recognitions results the working states of the rolling bearing were judged. The experimental results show that this method can be applied to rolling bearing fault diagnosis effectively.

A Feature-preserving Algorithm of Point Cloud Smoothing

Song Dahu, Li Zhongke, Wang Zhong, Sun Yuchun

2014, 25(11):  1498-1501. 

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This paper presented a feature-preserving algorithm to smooth 3D point cloud model. It began with constructing kd tree(k-dimensional tree) of the model, then computed the k-nearest neighbor of sampling point. Local geometry information was defined as the feature parameters, which considered the average distance, the normal angle among the point and its neighboring points, point curvature parameters. Then the sampling point was moved according to its characteristics and normal direction. Experimental results show that this method is effective to remove the noise point and preserve the feature of the original point cloud model.

Optimal Design of Monitoring Point of Multi-load-sensing Hydraulic System Based on the Maximum Fault Diagnosis Information Criterion

Guo Haoliang, Mu Xihui, Du Fengpo, Chen Jianhua

2014, 25(11):  1502-1506. 

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The monitoring points of the forklift multi-load-sensing hydraulic system were analyzed herein,and the test signals digraph and the relational model of “components-monitoring points” were built. Then, maximum fault diagnosis information criterion could be established by means of the concept of entropy in information theory, to confirm the optimal fault diagnosis strategy that comprehensively evaluated the most fault diagnosis information entropy with smaller cost and test time. Based on this criterion, the monitoring points of the multi-load-sensing hydraulic system were optimized, and the fault diagnosis isolated was drawn tree by step-test method finally.

Research on Improved Sensitivity Modification Method of Continuum Topology Optimization

Zhu Jianfeng, Lin Yi, Chen Xiaokai, Shi Guobiao

2014, 25(11):  1506-1510. 

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In order to solve checkerboard pattern problem, a new sensitivity modification technique was deduced to overcome instability phenomena of topology optimization based on the research of common sensitivity filter method. This method was to control filter factor of central element, which will influence the results of topology optimization. The classical compliance minimal numerical example was carried out by the new sensitivity modification method though different functions, the results demonstrate that this method can eliminate checkerboard pattern, mesh dependent and avoid over-averaging in domain.

Impacts of Operating and Health Conditions on Civil Aircraft Engine Turbine Blade Creep Life

Sun Jianzhong, Zuo Hongfu

2014, 25(11):  1511-1516. 

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The operating and health conditions of a gas turbine have a significant impacts on the in-service life of the turbine blade. Aiming at civil aircraft engine, using the engine performance model and the Larson-Miller creep life prediction model, this paper studied the impacts of the degradation of the engine, the atmospheric temperature and the reduced thrust takeoff on the turbine blade creep life. The simulation studies show that the degradation of the engine can accelerate the consumption of the blade creep life. 3% loss in the efficiency of the compressor will cause 80% decrease of the creep life of the blade. As the increase of the atmospheric temperature, the creep life of the blade will decrease exponentially. Reduced thrust takeoff can extend the life of the blade effectively, however as the takeoff thrust is further reduced, it has little effect on the extention of the blade life.  

Optimization Design Method of Automobile Styling Based on Evolution Strategy

Jing Chunhui, Zhao Jianghong

2014, 25(11):  1517-1523. 

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This paper combined the engineering methods like genetic algorithm as well as  the design methods like interactive evaluation, a set of optimization design methods for automobile styling was proposed by integrating engineering and design methods. The method was instructed by evolution theory, mapping automobile styling problems to mathematical model and using genetic algorithm to generate new design proposals. A multi-objective design space was quantized to restrain the generated design proposals. With the output of the proposal that correspond with the multi-objective design space, the interactive evaluation was utilized to evaluate the generated design proposal. Then the evaluation results as fitness were plugged into genetic algorithm until corresponding the design proposal. Finally, an optimization design method of vehicle styling was formed, which can solve problems of different aspects in anintergrated perspective. The  rationality and feasibility of this method was proven with an example of a small hatchback. This method can be extended to the field of multi-objective optimization concept generation and the evaluation of automobile styling and so on.

A Hierarchical and Fast Algorithm of Constrained Registration for Complex Blanks with Small Machining Allowance

Li Huan, Zhang Liyan, Zhou Liangming, Liu Shenglan

2014, 25(11):  1524-1529,1561. 

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For complex structure blanks with small machining allowance, small deviations may result in a shortage of allowance during the machining operation. In order to achieve optimal allocation of machining allowance, a hierarchical and fast algorithm of constrained registration between the dense scanned data of blank parts and the nominal finished part was presented. Firstly, with the aid of an elaborately built segmentation guide, each surface to be machined was separated from the point cloud by using points' local differential information. The minimal allowance constraint and an initial data set, which will be involved in the following registration process, were then assigned to each segmented surface respectively. The initial registration datasets were aligned to the design model by using multiplier methods, and then the measured data points that violate the allowance constraint were added iteratively into the current registration dataset until all the scanned points satisfied the allowance constraints. Experiments show that the proposed algorithm can achieve allowance-constrained registration with great efficiency.

Research on Hysteresis Characteristics of Vibratory Drum with Consideration on Jump Vibration

Zheng Shuhe, Lin Shuwen

2014, 25(11):  1530-1534. 

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The resilience against displacement revealed asymmetrical hysteresis during the vibratory compaction. As the soil compactness was high enough, the jump vibration of vibration roller was produced. An asymmetric hysteresis model was established in terms of segmental line according to soil property parameters. According to the first order approximation, the equivalent damping coefficient and equivalent stiffness coefficient were deduced through the harmonic linearization method. By means of numerical simulation, the hysteresis response characteristics of the drum were analyzed. During the beginning of vibration compaction, soil presents elastic-plastic characteristics and super-harmonics occur. With the increase of soil density during the ending of vibratory compaction, sub-harmonics may occur, which marks the occurrence of jump vibration.Under some conditions, chaos can be induced. Adjustment of excitation amplitude and excitation frequency can availably restrain jump vibration and chaos motion of the drum.

Bandelet Sparsity Based Compressive Sensing and Reconstruction of Texture Images for Mobile Robot Environmental Visions

Ma Ruyuan, Liu Jizhong, Jin Mingliang, Chai Guozhong, Wang Guanghui

2014, 25(11):  1535-1540. 

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The occurrence of compressed sampling provided a novel efficient, real-time processing methodology for robot environmental vision mass informations. Combined with the Bandelet transform's advantage of adaptive tracking regularization direction of image, the research of the compressed sampling and reconstruction of environmental texture images was carried out herein, which was based on the Bandelet transform and orthogonal matching pursuit (OMP) algorithm. The experimental results show: the reconstruction results with Bandelet sparsity (BS) and wavelet sparsity (WS) are similar with a bigger measurement value; however, with a smaller measurement value, the reconstruction based on WS takes on an unstable state and sometimes the image can not be reconstructed effectively; with the same given measurement value, the reconstruction ability of edge details in the image based on BS is better than that of WS. The results illustrate that under higher compressive sensing compression ratio, the BS based environmental texture image reconstruction has a better effectiveness and stability than that of WS based reconstruction.

Research on Non-linear Equivalent Elastic Modulus of Negative Poisson's Ratio Honeycomb Core-layer

Lu Chao, Li Yongxin, Wu Jinxi, Liu Ming, Li Tianqi

2014, 25(11):  1540-1544. 

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A negative Poisson's ratio honeycomb structure was designed and fabricated herein, a flexible cantilever model was used to analyze the bending deformation of the honeycomb panel under the situation of large deformation, then deduced a theoretical formula used to calculate the equivalent elastic modulus. Through the experimental comparison of finite element simulation and mechanical analysis, the paper verified the correctness of the non-linear theory formula, obtained nonlinear characteristics of the equivalent elastic modulus and the variation characteristic of the modulus of elasticity of the same direction and in different directions.It provides reference for flexible honeycomb core-layer structure of the engineering practices.

Quadric Surface Geometry Measurement Method for Point Clouds

Zheng Hongbo, Zhang Jiangwen, Tan Xiaojun, Qin Xujia, Chen Songhui

2014, 25(11):  1545-1549. 

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Geometry measurement based on point cloud is an important non-contact measurement method. A quadratic surface geometry measurement method was proposed based on undetermined coefficients for point cloud data. A unified framework for solving quadratic surface (including spherical, cylindrical and conical surface) was established. According to the quadratic surface equation and the different types geometric parameters of quadratic surface, the solving methods for the specific geometric parameters of the spherical, cylindrical and conical surface were implemented. Experimental results show that the method can measure the desired geometric parameters from point cloud data quickly and accurately, and it is a practical and feasible method.

Dynamic Energy Management Strategy of HEV Based on Driving Pattern Recognition

Qin Datong, Peng Zhiyuan, Liu Yonggang, Duan Zhihui, Yang Yang

2014, 25(11):  1550-1555. 

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Energy management strategy of HEV which was built in invariable cycle condition existed some limitations. 20 typical cycle conditions which standed for vehicle real driving conditions were chosen from ADVISOR software and key control parameters of each driving cycle were optimized by using particle swarm algorithm as the comprehensive goal of vehicle total fuel consumption and power battery life, relevant optimized results were saved in database, an energy management strategy of HEV based on driving pattern recognition was proposed. Finally, simulation for the energy management strategy was carried out under a random driving condition, simulation results show that vehicle fuel consumption is cut down 10.70%, temperature rise and average operation current are cut down 2.46℃ and 1.63A respectively by using dynamic energy management strategy compared with energy management strategy without driving pattern recognition.

High-dimensional Objective Optimization of Driver Side Restraint System Based on Reduction of Dimension

Bai Zhonghao, Lu Jing, Wang Yunlong, Fei Jing

2014, 25(11):  1556-1561. 

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To solve the problems that each sub-goal cannot reach optimum at the same time when multiple objectives were integrated into a single objective optimization, and using multi-objective genetic algorithm for high-dimensional objective optimization it was hard to find a representative non-inferiority Pareto solution, an optimization method coordinated occupant injury criteria with multi-objective evolutionary algorithm was proposed for optimizing the driver side restraint system of a passenger car. Based on the existed injury criterion and the latest version of FMVSS 208 and ECE R94, a new injury criterion (IC) was proposed for the problems mentioned above. The IC was used to reduce a high-dimensional objective optimization problem to a low-dimensional objective optimization problem. Sensitivity analysis and experimental design were conducted to get an approximate model, and NSGA-Ⅱ evolutionary algorithm was used to calculate non-inferiority Pareto solution. Then every non-inferiority Pareto solution was put into the injufy formula, which ordered in ascending order, to obtain an optimization solution that each sub goal can reach optimum at the same time, meanwhile, the injury value was minimum. The optimized results show that high-dimensional optimization problems of occupant restraint system are solved, and the effect of optimization is significant.