机械外文文献及翻译

内蒙古工业大学本科毕业设计外文翻译1与机械相关的外文及翻译MultidisciplinaryDesignOptimizationofModularIndustrialRobotsbyUtilizingHighLevelCADTemplates1、IntroductionInthedesignofcomplexandtightlyintegratedengineeringproducts,itisessentialtobeabletohandleinteractionsbetweendifferentsubsystemsofmultidisciplinarynature[1].Toachieveanoptimaldesign,aproductmustbetreatedasacompletesysteminsteadofdevelopingsubsystemsindependently[2].MDOhasbeenestablishedasaconvincingconcurrentdesignoptimizationtechniqueindevelopmentofsuchcomplexproducts[3,4].Furthermore,ithasbeenpointedoutthat,regardlessofdiscipline,basicallyallanalysesrequireinformationthathastobeextractedfromageometrymodel[5].Hence,accordingtoBow-cutt[1],inordertoenableintegrateddesignanalysisandoptimizationitisofvitalimportancetobeabletointegrateanautomatedparametricgeometrygenerationsystemintothedesignframework.Theautomatedgeometrygenerationisakeyenablerforso-calledgeometry-in-the-loop[6]multidisciplinarydesignframeworks,wheretheCADgeometriescanserveasframeworkintegratorsforotherengineeringtools.Toeliminatenoncreativework,methodsforcreationandautomaticgenerationofHLCthavebeensuggestedbyTarkian[7].TheprincipleofhighHLCtsissimilartohighlevelprimitives(HLP)suggestedbyLaRoccaandvanTooren[8],withtheexceptionthatHLCtsarecreatedandutilizedinaCADenvironment.Otherwise,thebasicsofbothHLPandHLCtcan,assuggestedbyLaRocca,becomparedtoparametricLEGOVRblockscontainingasetofdesignandanalysisparameters.Theseareproducedandstoredinlibraries,givingengineersoracomputeragentthepossibilitytofirsttopologicallyselectthetemplatesandthenmodifythemorphology,meaningthe内蒙古工业大学本科毕业设计外文翻译2shape,ofeachtemplateparametrically.2、MultidisciplinaryDesignFrameworkMDOisa“systematicapproachtodesignspaceexploration”[17],theimplementationofwhichallowsthedesignertomaptheinterdisciplinaryrelationsthatexistinasystem.Inthiswork,theMDOframeworkconsistsofageometrymodel,afiniteelement(FE)model,adynamicmodelandabasiccostmodel.Thegeometrymodelprovidestheanalysistoolswithgeometricinput.Thedynamicmodelrequiresmasspropertiessuchasmass,centerofgravity,andinertia.TheFEmodelneedsthemeshedgeometryoftherobotaswellastheforceandtorqueinteractionsbasedonresultsofdynamicsimulations.Highfidelitymodelsrequireanextensiveevaluationtimewhichhasbetakenintoaccount.ThisshortcomingisaddressedbyapplyingsurrogatemodelsfortheFEandtheCADmodels.Themodelsarebrieflypresentedbelow.2.1HighLevelCADTemplate—GeometryModelTraditionally,parametricCADismainlyfocusedonmorphologicalmodificationsofthegeometry.However,thereisalimittomorphologicalparameterizationasfollows:•Thegeometriescannotberadicallymodified.•Increasedgeometriccomplexitygreatlyincreasesparameterizationcomplexity.ThegeometrymodeloftherobotisgeneratedwithpresavedHLCts,createdinCATIAV5.Thesearetopologicallyinstantiatedwithuniqueinternaldesignvariables.Topologicalparameterizationallowsdeletion,modification,andadditionofgeometricelementswhichleadstoamuchgreaterdesignspacecaptured.ThreetypesofHLCtsareusedtodefinetheindustrialrobottopologically;DatumHLCtwhichincludeswireframereferencesrequiredforplacementfortheActuatorHLCTsandStructureHLCts,asseenFig.2.内蒙古工业大学本科毕业设计外文翻译3Fig.2Anindustrialrobot(left)andamodularindustrialrobot(right)ThenamesofthereferencesthatmustbeprovidedforeachHLCtinstantiationarestoredintheknowledgebase(seeAppen-dixA.4),whichissearchedthroughbytheinferenceengine.InAppendixA,pseudocodeexamplesdescribeshowthereferencesareretrievedandhowtheyarestoredintheknowledgebase.Theprocessstartsbytheuserdefiningthenumberofdegreesoffreedom(DOF)oftherobot(seeFig.3)andisrepeateduntilthenumberofaxis(i)isequaltotheuserdefinedDOF.InordertoinstantiatethefirstStructureHLCt,twoDatumandtwoactuatorinstancesareneeded.ReferencesfromthetwoDatuminstanceshelporientingthestructureinspace,whilethegeometriesoftheactuatorinstances,atbothendsofthelink,areusedtoconstructtheactuatorattachments,asseeninFigs.2and3.Fortheremaininglinks,onlyonenewinstanceofbothdatumandactuatorHLCtsarerequired,sincethedatumandactuatorinstancesfromadjacentlinksarealreadyavailable.AppendixA.2showsapseudocodeexampleofaninstantiationfunction.ThefirstinstantiateddatumHLCtisdefinedwithreferencetotheabsolutecoordinatesystem.TheremainingdatumHLCtinstancesareplacedinasequentialorder,wherethecoordinatesystemofpreviousinstancesisusedasreferencefordefiningthepositioninspaceaccordingtouserinputs(seealsoAppendixA.3).Furthermore,thetypeofeachactuatorandstructureinstanceisuserdefined.内蒙古工业大学本科毕业设计外文翻译4Fig.3ThehighlevelCADtemplateinstantiationprocessSinceitispossibletocreatenewHLCtsintheutilizedCADtool,theusersarenotforcedtomerelychoosefromthetemplatesavailable.NewHLCtscanbecreated,placedinthedatabaseandparametricallyinsertedintothemodels.2.2DynamicModelTheobjectiveofperformingdynamicsimulationofarobotistoevaluatesystemperformance,suchaspredictingaccelerationandtimeperformance,butitalsoyieldsloadsoneachactuatedaxis,neededforactuatorlifetimecalculationsandsubsequentstressanalysisbasedonFEcalculations.The内蒙古工业大学本科毕业设计外文翻译5dynamicmodelintheoutlinedframeworkisdevelopedinModelicau