液压动力系统中英文对照外文翻译文献.docx

液压动力系统中英文对照外文翻译文献.docx

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液压动力系统中英文对照外文翻译文献

中英文对照外文翻译文献

（文档含英文原文和中文翻译）

原文：

Feature-BasedComponentModelsforVirtualPrototypingofHydraulicSysterm

Abstract:

Thispaperproposesafeature-basedapproachforthevirtualprototypingofhydraulicsystems.Itpresentsaframeworkwhichallowsthedesignertodevelopavirtualhydraulicsystemprototypeinamoreintuitivemanner,i.e.throughassemblyofvirtualcomponentswithengineeringdata.Theapproachisbasedonidentifyingthedatarequiredforthedevelopmentofthevirtualprototypes,andseparatingtheinformationintobehaviour,structural,andproductattributes.Suitablerepresentationsoftheseattributesarepresented,andtheframeworkforthefeature-basedvirtualprototypingapproachisestablished,basedonthehierarchicalstructureofcomponentsinahydraulicsystem.Theproposedframeworknotonlyprovidesaprecisemodelofthehydraulicprototypebutalsooffersthepossibilityofdesigningvariationclassesofprototypeswhosemembersarederivedbychangingcertainvirtualcomponentswithdifferentfeatures.

Keywords:

Computer-aidedengineering;Fluidpowersystems;Virtualprototyping

1.Introduction

Hydraulicsystemdesigncanbeviewedasafunction-to-formtransformationprocessthatmapsanexplicitsetofrequirementsintoaphysicalrealisablefluidpowersystem.Theprocessinvolvesthreemainstages:

thefunctionalspecificationstage,theconfigurationdesignstage,andtheprototypingstage.Theformatforthedescriptionofthedesignineachstageisdifferent.

Thefunctionalspecificationstageconstitutestheinitialdesignwork.Theobjectiveistomapthedesignrequirements.Toachievethis,thedesignproblemsarespecifiedCorrespondenceandoffprintrequeststo:

DrS.C.Fok,SchooolofMechanicalandProductionEngineering,NanyangTechnologicalUniversity,NanyangAvenue,Singapore639798.Thedesignermustidentifytheperformanceattributes,whichcanincludepressure,force,speed,andflowrate,withtherequiredpropertiessuchassize,cost,safetyandoperatingsequence.performancerequirementsforeachattribute.Inthisstage,thedesignisabstractedintermsoftheperformanceattributeswithassociatedvalues.

Theobjectiveoftheconfigurationdesignstageistosynthesiseahydrauliccircuitthatperformstherequiredfunctionsconformingtotheperformancestandardswithindefinedconstraints.Atypicalhydraulicsystemismadeupofmanysubsystems.Thesmallestbuildingblockinasubsystemisthestandardhydrauliccomponent（suchasvalves,cylinders,pumps,etc.）.Eachtypeofstandardcomponentservesaspecificelementalfunction.Thedesigneffortintheconfigurationdesignstageisfundamentallyasearchforasetofoptimalarrangementsofstandardcomponents（i.e.hydrauliccircuit）tofulfilthefunctionalrequirementsofthesystem.Basedonthisframework,thedesignerswouldnormallydecomposetheoverallsystemfunctionsintermsofsubfunctions.Thiswillpartitionthesearchspaceandconfinethesearchforsmallerhydraulicsubcircuitstoperformthesubfunctions.

Computersareoftenusedtosupporttheconfigurationdesignprocess.Forexample,KotaandLeedevisedagraph-basedstrategytoautomatetheconfigurationofhydrauliccircuits.Afterthedevelopmentofthehydrauliccircuits,digitalsimulationtoolsareoftenusedtostudyandevaluatetheseconfigurations.Withthesetools,designerscancomparethebehaviourofdifferentcircuitsandalsoanalysetheeffectswhensubcircuitsarecombined.Intheconfigurationdesignstage,thedesignistraditionallyrepresentedasacircuitdrawingusingstandardiconstosymbolisethetypeofstandardcomponent.ThisisaformofdirectedgraphS（C,E）wherethecircuitScontainscomponentsCintheformofnodeswithrelationsbetweencomponentsdenotedbyedgesE.

Theprototypingstageistheverificationphaseofthesystemdesignprocesswheretheproposedhydrauliccircuitfromtheconfigurationdesignstageisdevelopedandevaluated.Physicalprototypingaimstobuildaphysicalprototypeofthehydraulicsystem666S.C.Foketal.usingindustrialavailablecomponents.Theprocessofphysicalprototypinginvolvesthefollowing:

Searchforappropriatestandardcomponentsfromdifferentmanufacturers.Pre-evaluationandselectionofcomponentsbasedonindividualcomponentcost,size,andspecification,andcompatibilityfactorsbetweencomponents.Procurementandassemblyoftheselectedcomponents.Testandevaluatethephysicalprototypebasedontheoverallsystemrequirements.Useothercomponentsorredesignthecircuit（orsubcircuits）

ifnecessary.Besidesdynamics,thedevelopmentofthephysicalprototypemusttakeintoconsiderationotherfactorsincludingstructure,cost,andweight.Thedynamicsdataareusedtoconfirmthefluidpowersystembehaviourwhereasthegeometricinformationisusedtoexaminetheassemblyproperties.Thedevelopmentofthephysicalprototypewillprovidetheactualperformance,structure,andcostofthedesign.

Themaindisadvantageofphysicalprototypingisthatitisverytediousandtimeconsumingtolookforasetofsuitablecombinationsofstandardcomponentsfromamongsomanymanufacturers.Althoughthebasicfunctionsofthesametypesofstandardcomponentfromdifferentmanufacturersdonotdiffer,theirdynamics,structuralandcostcharacteristicsmaynotbesimilar,becauseofdesignvariation.Hence,foragivenhydrauliccircuit,differentcombinationsofpartsfromdifferent

manufacturerscanhaveimplicationsontheresultingsystem,intermsofdynamics,structure,andcost.Valueengineeringcanbeusedatthisstagetoimprovethesystemdesignbyimprovingtheattributesatthecomponentlevel.Thisincludesmaximizingtheperformance-to-costratioandminimisingthe

size-to-performanceratio.Virtualprototypingcanbeviewedasacomputer-aideddesignprocess,whichemploysmodellingandsimulatingtoolstoaddressthebroadissuesofphysicallayout,operationalconcept,functionalspecifications,anddynamicsanalysisundervariousoperatingenvironments.Themainadvantageofvirtualprototypingisthatahydraulicsystemprototypecanbeassembled,analysed,andmodifiedusingdigitalcomputerswithouttheneedforphysicalcomponents,thussavingleadtimeandcost.

Themainrequirementofavirtualhydraulicsystemprototypeistoprovidethesameinformationasaphysicalprototypeforthedesignertomakedecisions.Toachievethis,thevirtualprototypemustprovidesuitableandcomprehensiverepresentationsofdifferentdata.Furthermore,transformationfromonerepresentationtoanothershouldproceedformally.Xiangetal.havereviewedthepastandcurrentcomputer-aideddesignandprototypingtoolsforfluidpowersystems.Theworkrevealedthatthecurrenttoolscouldnotprovideacompleterepresentationofthedesignabstractionsattheprototypingstagefordesignjudgement.Mostofthetoolsconcentrateonthedynamicsbehaviour.Vitalgeometricalandproductinformationthatrelatestothesystemprototypeconsiderationandevaluationisfrequentlymissing.Toadvancethedevelopmentofcomputer-aidedvirtualprototypingtoolsforfluidpowersystems,thereisaneedtoaddresstheformalrepresentationsofdifferentabstractionsofbehaviour,structural,andproductdataalongwiththeirintegration.Thispaperfocusesontheseissuesandproposestheformalismofaunifiedcomponentmodelandthetaxonomybasedonthefeature-basedapproach.InSection2,wediscussthefeature-basedapproachfocusingonthekeyinformationandtheirrepresentationsrequiredforhydraulicsystemprototyping.Section3presentsaformalismofthefeature-basedmodelandstructureforthedevelopmentofvirtualhydraulicsystemprototypes.Thestructureisillustratedwithanexample.FutureworkandconclusionsaregiveninSection4.

2.Feature-BasedApproach

Featurescanbedefinedasinformationsetsthatrefertoaspectsofattributesthatcanbeusedinreasoningaboutthedesign,engineeringormanufacturingprocesses.TheconceptofusingfeaturestointegrateCAD/CAPP/CAMisnotnewandtherearemanypapersontheapplicationofthisapproachinCIM.Inalltheseapplications,thefeaturemodelisregardedasthebasiswhereasdesignbyfeaturesisthekeyfortheintegration.Todevelopafeaturemodel,therelevantinformationconcerningthedesignmustbeidentifiedandgroupedintosetsbasedonthenatureoftheinformation.Therelevantinformationshouldcontainsufficientknowledgeforactivitiessuchasdesign,analysis,test,documentation,inspection,andassembly,aswellassupportvariousadministrativeandlogisticfunctions.Designbyfeaturesistheprocessofbuildingamodelofthedesignusingfeaturesasprimitiveentities.Thefeaturemodelprovidesthestandardisationofrelevantdata.Throughthedesignbyfeaturesapproach,vitalknowledgeofthedesignwillbegeneratedandstored.Together,thefeaturemodelandthedesignbyfeaturesapproachwillprovidetheessentialinformation,whichcanbeused,notonlyforthesimultaneousconsiderationofmanydifferentconcernswiththedesign,butalsotointerfacethemanyactivitiesinthedesignrealisationprocess,includingthelifecyclesupportoperations.Themaindrawbackofthefeature-baseddesignapproachisthatthefeaturemodelshouldbeproperlydefined.Thiscanbedifficult,asfeaturesaresetsofknowledgethatareapplicationdependent.Theorganisationofthefeaturescanalsobeapplicationspecific.Non-trivialdata-managementproblemscouldariseifthefeaturemodelisnotproperlydefined.Toavoidtheseproblems,thetype,representationandstructureofthefeaturesshouldberesolvedpriortousingthefeature-baseddesignmethodology.Themainconce