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APPROACH TO IMPROVEMENT OF ROBOT TRAJECTORY ACCURACY BY DYNAMIC COMPENSATION

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Chinese Journal of Mechanical Engineering 2004年第3期17卷 446-449页

作者： WangGang RenGuoli YanXiang＇an WangGuodong departmentofmechanicalengineenng TianjinUniversityTianjin300072China

Some dynamic factors, such as inertial forces and friction, may affect therobot trajectory accuracy. But these effects are not taken into account in robot motion controlschemes. Dynamic control methods, on the other hand, require the dynamic model of robot and theimplementation of new type controller. A method to improve robot trajectory accuracy by dynamiccompensation in robot motion control system is proposed. The dynamic compensation is applied as anadditional velocity feedforward and a multilayer neural network is employed to realize the robotinverse dynamics. The complicated dynamic parameter identification problem becomes a learningprocess of neural network connecting weights under supervision. The finite Fourier series is used toactivate each actuator of robot joints for obtaining training samples. Robot control system,consisting of an industrial computer and a digital motion controller, is implemented. The system isof open architecture with velocity feedforward function. The proposed method is not model-based andcombines the advantages of close-loop position control and computed torque control. Experimentalresults have shown that the method is validatities to improve the robot trajectory accuracy.

关键词： Robot Dynamic compensation Trajectory accuracy Identification

ADAPTIVE CONTROL OF FLEXIBLE BEAM WITH UNKNOWN DEAD-ZONE IN THE DRIVING MOTOR

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Chinese Journal of Mechanical Engineering 2004年第3期17卷 327-331页

作者： WangXingsong HongHenry SuChunyi departmentofmechanicalengineenng SoutheastUniversityNanjing210096China departmentofmechanicalengineenng ConcordiaUniversityMontrealQuebecH3G1M8Canada

Adaptive control of a flexible beam system preceded by an unknown dead-zonein the driving motor is investigated in state space form. By introducing an important lemma forsimplifying error equation between the flexible beam model and the matching reference model, arobust adaptive control scheme is developed by involving the dead-zone inverse terms. The newadaptive control law ensures global stability of the entire system and achieves desired trackingprecision even when the slopes of the dead-zone are not equal. Simulations performed on a typicalflexible beam system illustrate and clarify the validity of this approach.

关键词： Adaptive control Flexible beam Dead-zone

DESIGN REUSE METHOD FOR ASSEMBLIES IN CONCEPT DESIGN

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Chinese Journal of Mechanical Engineering 2005年第1期18卷 132-138页

作者： DongYan TanJianrong XuJing StateKeyLaboratoryofCAD＆CG ZhejiangUniversityHangzhou310027China departmentofmechanicalengineenng ZhejiangOceanUniversityZhoushan316004China

Aiming at difficult sorting and retrieving complicated structure assembliesin assembly lib, a method for compartmentalizing assembly design resource by conceptual productstructure model is presented. The similar assembly retrieval mechanisms of symbol assembly relationgraph matching and symbol assembly relation graph similarity are discussed. The method is validatedby taking valve rod assemblies as example.

关键词： Design reuse Similar assembly retrieval Assembly design lib

EFFICIENCY ANALYSIS OF DOUBLE CRANK RING-PLATE-TYPE PIN-CYCLOIDAL GEAR PLANETARY DRIVE

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Chinese Journal of Mechanical Engineering 2003年第3期16卷 252-255页

作者： LiXin HeWeidong LindaSchmidt LiLixing departmentofmechanicalengineenng UniversityofMarylandMarylandU.S.A. DepartmentofMechanicalEngineering DalianRailwayInstituteDalian116028China DeparlmentofMechanicalEngineering UniversityofMarylandMarylandU.S.A.

From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental study has been conducted. The tested value of theefficiency of a sample set of the new-type drive in the experiment agrees with the calculated *** shows that the new-type drive is of not merely high bearing capacity, but also quite highefficiency.

关键词： Double crank ring-plate-type Pin-cycloidal gear planetary drive Meshefficiency

IDENTIFICATION OF TIME-VARYING MODAL PARAMETERS USING LINEAR TIME-FREQUENCY REPRESENTATION

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 445-448页

作者： XuXiuzhong ZhangZhiyi HuaHongxing ChenZhaoneng departmentofmechanicalengineenng ShanghaiMantimeUniversityShanghai200135China NationalKeyLaboratoryofVibrationShock＆Noise ShanghaiJiaoton9UniversityShanghai200030China SchoolofMechanicalEngineering ShanghaiJiaotongUniversityShanghai200030China

A new method of parameter identification based on linear time-frequencyrepresentation and Hubert transform is proposed to identity modal parameters of linear time-varyingsystems from measured vibration responses. Using Gabor expansion and synthesis theory, measuredresponses are represented in the time-frequency domain and modal components are reconstructed bytime-frequency filtering. The Hilbert transform is applied to obtain time histories of the amplitudeand phase angle of each modal component, from which time-varying frequencies and damping ratios areidentified. The proposed method has been demonstrated with a numerical example in which a lineartime-varying system of two degrees of freedom is used to validate the identification scheme based ontime-frequency representation. Simulation results have indicated that time-frequency representationpresents an effective tool for modal parameter identification of time-varying systems.

关键词： Linear time-varying system Modal parameter identification Hilberttransform Gabor expansion

PHOTOCATALYTIC ACTIVITY OF TiO_2 NANOPARTICLE FLUID PREPARED BY COMBINED ASNSS

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China Particuology 2004年第4期2卷 171-173页

作者： HoChang Tsing-TshinTsung Hong-MingLin Chung-KweiLin departmentofmechanicalengineenng TaipeiUniversityofTechnologyTaipei106China Authortowhomcorrespondenceshouldbeaddressed DepartmentofMaterialsScience Feng-Chia-UniversityTaichung407China

In this article, low-pressure control methods for a combined arc submerged nanoparticle synthesis system (ASNSS) was proposed and developed for TiO2 nanoparticle fabrication. The photocatalytic reaction is carried out in a photochemical reactor. The UV light is obtained from UV-lamps with wavelength of (253.7±0.8) nm. The UV-Vis spectrometry is used to monitor the absorbance spectra of methylene blue as a function of illumination time. Experimental results show that the rate constant of photocatalytic reaction of TiO2 nanoparticles for methylene blue is 0.0365 min?1. The surface adsorption plays an important role in the decomposition of methylene blue. Experimental results indicate that the TiO2 nanoparticle fluid possesses excellent photocatalytic activity in photodegradation of methylene blue.

关键词： ASNSS nanoparticle fluid photocatalytic properties

OPTIMIZATION STUDY IN MANUFACTURING PROCESS FOR PC/ABS BLENDS

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Chinese Journal of Mechanical Engineering 2003年第3期16卷 233-236页

作者： HuangChenghung FungChinping ChangShihhsing HwangJiunren DoongJiliang DepartmentofMechanicalEngneering NationalCentralUniversityChungliTaiwan320China DepartmentofSystemEngineering ChungChengInstituteofTechnologyTaoyuanTaiwan335China DepartmentofIndustrialManagement VanNungInstituteofTechnologyChungliTaiwan320China departmentofmechanicalengineenng NationalCentralUniversityChungliTaiwan320China

The optimization of injection molding process for polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blends is studied using Taguchi method and principalcomponent analysis (PCA). Four controllable process factors are studied at three levels each in themanufacturing process. The L_9 orthogonal array is conducted to determine the optimum processfactor/level combination for single quality of mechanical properties. In addition, the principalcomponent analysis is employed to trans-form the correlated mechanical properties to a set ofuncorrelated components and to evaluate a comprehensive index for multi-response cases. Then theoptimum process factor/level combination for multiple qualities can be determined. Finally, theanalysis of variance is used to find out the most influential injection molding parameter for singleand multiple qualities problems.

关键词： PC/ABS Injection molding Optimization Taguchi method Principal componentanalysis Mechanical properties