Table of Content

10 April 2010, Volume 21 Issue 7

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Dynamics Design of Aerostatic Bearings in Dual Gas-lubricated Stages

XIE Yi-Xi, CHEN Hua-Dong, LUO Xin

2010, 21(7):  757-761. 

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The problem how to design the dynamics parameters of aerostatic bearings was investigated. The general dynamics characteristics of aerostatic bearings were analyzed, and the dynamical design principles of aerostatic bearings for reducing the synchronization error of dual-stages were proposed. Then, two dynamics designs of aerostatic bearings of dual-stages were given to describe these principles. It is concluded that many factors need to be considered in the design of aerostatic bearings, including load-capacity, stiffness and damping etc, and the design principles that the aerostatic bearings nature frequency should be away from working frequencies and structure frequencies so as to avoid resonance. When the dual-stages require the synchronization, the natural frequencies of aerostatic bearings should be equal to each other, so that the stages have the same dynamics performance and the same response characteristics for driving instructions and interference to ensure the synchronization accuracy of dual-stages.

Multi-objective Topological Optimization Design of Ultra-precision Mechanical Structure

DONG Li-Li, SHU Yu, NIU Xiao-Tie, DUAN An-Hong, LIANG Lin-Quan

2010, 21(7):  761-765. 

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Based on the topological optimization and layered decision-making theory of multi-objective optimization, a new methodology of multi-objective topological optimization design (MOTOD) was proposed, and the method was applied in the optimization design of structures in the key unit of ultra-precision stages. The simulation results based on ANSYS prove that MOTOD significantly improve the static characteristics, dynamic characteristics and the design efficiency of multi-objective structure optimization design, satisfies the rigorous requirements in performance of ultra-precision structures, and provides a theoretical guide and method for modern structure design and improvement.

 

Research and Development on Intelligent Inspection System for Wine Based on Machine Vision

ZHOU Bo-Wen, WANG Yao-Na, ZHANG Hui, GE Ji

2010, 21(7):  766-772,821. 

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A machine-vision-based intelligent inspection system was presented.The linear convection mechanical structure and electric control system based on industrial computer and programmable logical controller were illustrated in detail.A method using high-speed cameras was applied for obtaining the image sequences.The sub-pixel edge location method was used for confirming the inspection region.The methods of cumulative difference and the minimum space of the cross-entropy threshold segmentation were used to acquire the moving targets.The foreign substances were judged by the moving trajectory.Finally,according to the metrical data of foreign substances,a robot gave an judgment that the product was qualified or unqualified. A great deal of experiments demonstrate that the detection algorithm is effective and the device is feasible.

Functional Assessment and Manufacturing Control of Multi-scale Surfaces

HU Zhao-Wen, LIU Xiao-Jun, WANG Jing, LIU Kun

2010, 21(7):  773-777. 

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Due to the fact that different components of texture generated by different manufacturing processes has different scales and tribological properties,the key to functional assessment of multi-scale surfaces is to identify roughness components and to describe their functional properties.A method of assessing the functional properties of multi-scale surface was presented based on material probability curve and material ratio curve,and manufacturing control to meet the functional requirements for surface was investigated.Application to plateau honed cylinder liner suggests that the method is effective,and manufacturing quality control can be achieved providing that an empirical model relating surface performance and manufacturing process is developed by means of roughness parameters defined in ISO13565-3.

Knowledge Representation and Modeling Oriented to Reusable Complex Product Design

TU Li, ZHANG Shu-Wei

2010, 21(7):  777-781. 

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The function-behavior-structure(FBS) mapping model and organization model were built.The functional and geometric information were encapsulated.The structural scheme was stored in knowledge base by the function decomposition algorithm to develop knowledge representing and handling capability.The method is an efficient way to respond design requirements rapidly and is applied in mass customization of forklift products. 

Whole Machine Dynamic Characteristic Analysis of High Speed Grinder 

CUI Zhong, WEN Gui-Lin, CHEN Gui-Beng, XU Hong-Wei, BANG Ke-Li

2010, 21(7):  782-787. 

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A 3D finite element model of high-speed camshaft grinder was set up, and the fundamental parameters of joint surface were identified by inverse solution. By modal analysis for the whole grinder, the weak points of machine dynamic performance were found. Then, the investigation of the low modes for the whole machine revealed the effect of the stiffness parameters at unit joint surface, and the suggestions of structural improvement were proposed. The radial basis function(RBF) model was used to express the implicit function relation, which was about the joint stiffness of bed-base plate system and the frequency of the system. The stiffness parameters of joint surface were determined, by means of mode test for the system and optimization. The results show that this method is simple and available for the whole grinder modeling and the dynamic performance analysis, and the method of increasing the number of bolt on the base plate can improve a dynamic characteristics of the high-speed grinder.

A New Blind Source Separation Algorithm Based on Cumulants and Its Applications

LEI Yan-Bin, LI Shun-Ming, HAO Jing-Jing

2010, 21(7):  787-792. 

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Combing the advantages of second- and fourth-order, a new algorithm based on second- and fourth-order cumulants simultaneous diagonallization was proposed, which was based on joint approximate diagonallization. A robust whitening method was introduced, which can effectively reduce the influence on the separation precision. Compared this algorithm's performance to JADE algorithm's and second-order algorithm's, the results show that the algorithm has the advantages of fast convergence speed and high separation precision. Through two simulation experiments, the results show that the proposed algorithm can separate speech signals and extract the independent sources from the hybrid mixture of any super-Gaussian and sub-Gaussian signals effectively. At last, this algorithm was applied to separate the practical rotor's vibration signals, the rotors' complex vibration signals are separated successfully. It provides a new method for separation of complex vibration signals in fault diagnosis processes.

Active Vibration Robust Control of Flexible Plate with Malfunction Piezoelectric Actuators

LI Dong-Wei, HE Zhong-Bei, TANG Wei, ZHANG Lei, MAO Zhi-Dun

2010, 21(7):  793-799. 

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Firstly, a state space experimental model of flexible plate vibration system with some malfunction connection piezoelectric actuator pairs were identified by the multivariable identification theory. Based on the identified results, the canonical uncertain block diagonal matrix extraction method of malfunction actuators was designed by means of singular value decomposition of the input matrix and linear fraction transformation.At the same time, the residual modal was expressed by the low band filter, then considered the disturbance suppression and control gain constraint performance of the close-loop system, the virtual uncertainty was introduced to establish the μ-synthesis solution procedure. The test results show that when there is connection malfunction on the piezoelectric actuators, compared to the μ-synthesis control without considering the malfunction, the initial perturbation log attenuation ratio will be increased 3 times, so the performance robustness of the mixed uncertainty model of the flexible plate is solved effectively.

Sensitivity Temperature Coefficient Compensation Based on Pressure Sensor Integrated Constant Current

ZHENG Bei-Rong, XUE Wei, ZHOU Chen, ZHANG Miao

2010, 21(7):  800-803. 

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For high accuracy and wide temperature range applications,

this paper presented a novel pressure sensitivity temperature coefficient(TCS) compensation

method,using integrated constant current network.A quantitative compensation

formula was introduced in mathematics.During experiments,the absolute value of the compensated

TCS is easy to be 10×10-6/℃~100 ×10-6/℃ by individual adjustment and calibration of each device's temperature compensation.Therefore the feasibility and practicability of this technology were tested.Again,the disadvantages

were discussed after the research of the experimental data and the improvement methods were also given in the designing period.This technology exhibits the great potential practical value. These applications were promoted in the volume production.The operating performances of these pressure sensors using this technology were proved to be reliable. 

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LI Hao-Lin, YING Xing-Juan

2010, 21(7):  804-808. 

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Friction Compensation of Aircraft Actuator Based on Soliding Model Control

WANG Yong-Bin, LIN Hui

2010, 21(7):  809-914. 

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A nonlinear SMC scheme was proposed against the harmful effects with nonlinear friction on aircraft EHA servo systems. Based on the analysis of EHA and the nonlinear friction,the models of EHA servo system were established. With comparison between SMC and typical PID control,it is remarkable that the trajectory oscillation of step signals is restrained and the deadband of sine signals is avoided with SMC. The simulation results indicate that the Stribeck model of nonlinear friction established is reasonable and the well control of SMC is took on with the nonlinear objectives.

An Immune Co-evolution Algorithm for Balancing and Sequencing on Mixed-Model U-Lines

LIU Dan, LOU Pei-Huang, TANG Dui-Bing, YANG Lei

2010, 21(7):  815-821. 

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The multi-objective optimization problem of balancing and scheduling on mixed-model U-lines had been studied.An immune co-evolutionary algorithm based on Pareto front had been proposed.Two monoclonal antibody populations,which were coded differently and co-evolve with each

other,had been designed according to the sub problems of balancing and scheduling.A polyclonal antibody population was used to save the optimal complete solutions and the elitism was executed so that the sub populations compete

as they co-evolve.The antibody affinity was evaluated from the phenotype as well as the genotype and the collaboration formation mechanism had been ameliorated to enhance the performance of the algorithm.The algorithm has been proved to have a better performance of convergence and be more suitable

for the proposed problem by comparison of the results of three series of experiments from different aspects.

Reasearch on Prediction of Cutting Surface Roughness Based on Wavelet Packet Analysis and Elman Network

CHI Jun, CHEN Lian-Qing, YANG Chao-Zhen

2010, 21(7):  822-826. 

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 A forecast method based on relax-type wavelet network for cutting surface toughness was indicated. The forecasting network structure was established by considering the influence of cutting parameters and vibration. The noise in cutting vibration signals was filtered with the reformed wavelet pack algorithm to avoid aliasing in frequency domain. The real-time forecast was achieved by the nonlinear mapping and learning mechanism in Elman network according to the vibration acceleration and cutting parameters. The weights in network were optimized with genetic algorithm in advance to reduce learning time. The forecasting error of this method is less than 3% in experiments.

Aero-engine Wear State Recognition Based on Image Analysis and Novelty Detection

TAN Zhen-Zhen, CHEN Guan, CHEN Li-Bei, LI Yuan

2010, 21(7):  827-831. 

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An automatic identification technology based on engine oil filter debris image was investigated. Firstly, characteristic quantities of oil filter images which can reflect wear state were extracted with the maximum entropy method and mathematical morphology method. Then, oil filter images that can reflect normal state were collected, and the normal training sample sets were constructed through image analysis and feature extraction. Finally, the normal domain of oil filter image was obtained through normal training samples using novelty detection, and to identify the severity of the wear state of aero-engine according to the normal domain. Besides, the self-adaptive parameter of novelty detection was obtained by genetic algorithm. Engine oil filter monitoring system (EOFMS) was developed, and the recognition function of wear debris images based on novelty detection was realized. Besides, the experiments using actual aero-engine oil filter debris images were carried out, and the results show the effectiveness of the method.

Research and Application on Diffuse Axonal Injury Experimental Device

DIAO Zhi-Qiu, XIE Le, MA Yan-Bin, WANG Hong-Cai, PENG Xiao-Long

2010, 21(7):  832-835. 

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Diffuse axonal injury (DAI), which is the most important types of brain injury, is the main cause of death, serious disability and vegetative being. In order to study the DAI, a experimental device with high stability and good reproducibility was designed, which can simulate the clinical process of the DAI injury. This paper described the design process in detail, such as the choosing of the driving force, the design of the linked structure, the design of limited block and the choice of sensors. Finally, the verification of feasibility and superiority of the device by rat experiments was done.

 

Research on Adaptive Control for a Planar Parallel Mechanism

AO Yin-Hui

2010, 21(7):  835-838. 

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The dynamics of PM is nonlinear and the parameters are not certain.Control methods based on kinematics or PID algorithm are not adaptive and can not obtain high performance. This paper presented an adaptive algorithm based on the compute torque structure. The inverse dynamics was computed with ideal actuator values and the feedback torque was calculated in actuator space. With a planar PM platform, the experimental results show that the adaptive algorithm can get much better performance than that of PID or fuzzy PID algorithm.

Research and Design on a Device to Apply Down-force in Chemical Mechanical Polishing Process

WANG Cai-Ling, KANG Ren-Ke, JIN Zhu-Ji

2010, 21(7):  839-842,864. 

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With the use of low-k material, low down-force CMP has been a crucial technology for the equipment design. The technology of elastic compound elements was promoted to meet the needs of the low down-force. The assembly of the elastic element applied down-force in mechanical model. And down-force on the wafer was controlled by deformation of the pressure element. Requirements and the accuracy of pressure element were analyzed in theory, and the experimental results tallies basically with it. Also the down-force was in linear to the deformation of it. The pressure element can be regulated from zero in high precision under the low down force.

Effect of Temperature on Friction and Wear Behaviors of Carbon/Copper with and without Electric Current

DING Chao, WANG Xin, CHEN Guang-Xiong, SHU Min-Hao

2010, 21(7):  843-847. 

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 Through a series of experimental tests on a pin-on-disc tester, the tribology behavior of carbon/copper pair with and without electric current was verified. The results indicate that the temperature of frictional couple rises continuously in the process of friction and wear, and the wear valume of sliding strip increases with increasing of temperature. And the temperature of the frictional couple with electric current is higher than that without electric current. Without electric current, the friction coefficient firstly increases and then decreases with increasing of the temperature. With electric current, the friction coefficient decreases gradually with increasing of the temperature. Through observing the surface topography of the carbon sliding strip before and after wear, it is found that the wear surface becomes smoother and smoother with increasing of the temperature. Abrasive and adhesive wear dominate during no electric current. Oxidation wear and arc erosion dominate under electric current. By the EDS(energy dispersive spectrometer) analysis on worn carbon sliding strip, it can be found that element transfer and oxidation occur irregularly in the process of the friction and wear.

Study and FEM Analysis on Discharge Erosion Mechanism of Monocrystalline Silicon

LI Jian, LIU Zhi-Dong, QIU Meng-Bei, TIAN Zong-Jun, HONG Wei

2010, 21(7):  847-851. 

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Assumption of erosion mechanism of EDM on monocrystalline silicon was proposed. It was considered that thermal stress played the leading role during the erosion process. Discharge model of single pulse was established on WEDM, the temperature field and the thermal stress field of single-pulse discharge condition was analyzed based on finite element method. Theoretical amount of erosion of the silicon was calculated under the temperature field and thermal stress field, and was compared with the actual amount of erosion in tests. Results show that erosion process of the monocrystalline silicon EDM can be described by this assumption of erosion mechanism.

TRIZ Based Design for Disassembly of Joint Structure

LIU Zhi-Feng, YANG Meng, ZHANG Lei

2010, 21(7):  852-859. 

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For solving the problems of DFD in green design,TRIZ methods

 were used to provide innovative ideas to improve the disassembly properties of joint structure between product parts.Two DFD methods were proposed through constructing an associated table between 48 engineering parameters in new TRIZ conflict matrix and

disassembly attributes of joint structure,and through establishing TRIZ substance-field

 model of joint structure,the disassembly property of product can be improved by the combination of TRIZ principle of conflict resolution and substance-field analysis.At last,a design case proves the feasibility of the proposed methods.

Study and Application of Crown Feedback Control System in Hot Tandem Rolling

LIU Tian-Wu, HE An-Rui, YANG Chuo, CHEN Bai-Gong

2010, 21(7):  860-864. 

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It is still a problem to choose the strategy of crown feedback. According to the configuration of Angang 1580HSM, a method of choosing strategy was studied, the strategy that all stands took part in control was gained and the formula of crown deviation distribution was established. And then, the control model for crown feedback was built, meanwhile, on-line programming and debugging were proceeded. The statistical data shows that crown control precision is improved with crown feedback control system.

 

Study on Optimization of Pressure Center for Progressive Die Based on Torque Equilibrium and Simulated Annealing

CHEN Wei, ZHOU Zhi-Fu, JIANG Bing-Yun, SUN Zhi-Gao, DAI Feng-Ze

2010, 21(7):  865-867,871. 

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The principle of torque equilibrium was adopted to construct the solving model of pressure center for progressive die. The formula was derived from solving model to calculate the offset value between the die center and the slide center, and the torque deviation varied with time was also given out. Based on this method, an optimization method was proposed and the objective function and constrained functions were established to decrease the deviation of the torque. Each stamping punch force was obtained and the value of center deviation was optimized, by using simulated annealing (SA) algorithm method combined with finite element technology. Take the progressive die of shell sheet as an example, the method was validated accuracy and efficiency to the optimization of the pressure center progressive die through comparison with theory.

Effect of New Vermicular Agent on Microstucture and Properties of Compacted Graphite Iron for Diesel Engine Cylinder Block

CA An-Ke, TUN He-Bao, FAN Sui-Chang, ZHANG Dun-Xiang, JIA Zhi-Quan, FAN Zi-Tian

2010, 21(7):  868-871. 

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This paper researched the graphite morphology, the chemical component and mechanical properties of compacted graphite irons by crushing new vermicular agent into the special ladle. The results indicate that 0.015%～0.022%Mg and 0.068%～0.098%Re are the optimal choice to obtaining 50%～80% vermicular graphite for the compacted graphite irons, which will provide theoretical principle to the steady product of compacted graphite irons.

Control Strategy for a Full Hybrid Vehicle with Single Motor

DAI Yi-Fan, LUO Yu-Gong, BIAN Meng-Yuan, LI Ke-Jiang

2010, 21(7):  872-876. 

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A layered control system was established based

on a newly developed full hybrid vehicle with the structure of single motor and double clutches, energy management strategy was instituted and the concerted control strategy for dynamic process of engine start while driving was studied.The energy management strategy was validated by a developed forward simulation model, a fuel consumption reduction of 34% in the NEDC driving cycle is achieved.A dynamic test bench was built to confirm the concerted control strategy for dynamic process of engine start while driving.

Dynamic Loading of Vehicle Testing Bed Based on Model Reference Control

MO Zhi-Yong, ZHANG Wei-Gong, JI Tong-Zhou

2010, 21(7):  877-881. 

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Dynamic loading is an important technology of vehicle testing device.In order to overcome the difficulty of torque control in traditional loading method,DTC was adopted.Model parameters varied greatly according to different types of vehicle,so model reference control was taken to improve the model's adaptability.Aimed at reducing dynamic errors further,an expert PID control was selected to design the torque controller.A simulation model was set up. Simulation outcome shows that compensating torque can be rapidly regulated according to demands of dynamic loading.Stable-state error is less than one percent,and dynamic error is much more less than that of traditional PID.In the

end,a conclusion is drawn from comparison study that dynamic loading with electrical simulation proposed meets the demands of vehicle testing,and its synthetic performance is superior to traditional static loading.