与机械有关的外文及翻译MultidisciplinaryDesignOptimizationofModularIndustrialRobotsbyUtilizingHighLevelCADTemplates1、IntroductionInthedesignofcomplexandtightlyintegratedengineeringproducts,itisessentialtobeabletohandleinteractionsbetweendifferentsubsystemsofmultidisciplinarynature1.Toachieveanoptimaldesign,aproductmustbetreatedasacompletesysteminsteadofdevelopingsubsystemsindependently2.MDOhasbeenestablishedasaconvincingconcurrentdesignoptimizationtechniqueindevelopmentofsuchcomplexproducts3,4.Furthermore,ithasbeenpointedoutthat,regardlessofdiscipline,basicallyallanalysesrequireinformationthathastobeextractedfromageometrymodel5. Hence,accordingtoBow-cutt1,inordertoenableintegrateddesignanalysisandoptimizationitisofvitalimportancetobeabletointegrateanautomatedparametricgeometrygenerationsystemintothedesignframework.Theautomatedgeometrygenerationisakeyenablerforso-calledgeometry-in-the-loop6multidisciplinarydesignframeworks,wheretheCADgeometriescanserveasframeworkintegratorsforotherengineeringtools.Toeliminatenoncreativework,methodsforcreationandautomaticgenerationofHLCthavebeensuggestedbyTarkian7.TheprincipleofhighHLCtsissimilartohighlevelprimitives(HLP)suggestedbyLaRoccaandvanTooren8,withtheexceptionthatHLCtsarecreatedandutilizedinaCADenvironment.Otherwise,thebasicsofbothHLPandHLCtcan,assuggestedbyLaRocca,becomparedtoparametricLEGOVRblockscontainingasetofdesignandanalysisparameters.Theseareproducedandstoredinlibraries,givingengineersoracomputeragentthepossibilitytofirsttopologicallyselectthetemplatesandthenmodifythemorphology,meaningtheshape,ofeachtemplateparametrically.2、MultidisciplinaryDesignFrameworkMDOisa“systematicapproachtodesignspaceexploration”17,theimplementationofwhichallowsthedesignertomaptheinterdisciplinaryrelationsthatexistinasystem.Inthiswork,theMDOframeworkconsistsofageometrymodel,afiniteelement(FE)model,adynamicmodelandabasiccostmodel.Thegeometrymodelprovidestheanalysistoolswithgeometricinput.Thedynamicmodelrequiresmasspropertiessuchasmass,centerofgravity,andinertia.TheFEmodelneedsthemeshedgeometryoftherobotaswellastheforceandtorqueinteractionsbasedonresultsofdynamicsimulations.Highfidelitymodelsrequireanextensiveevaluationtimewhichhasbetakenintoaccount.ThisshortcomingisaddressedbyapplyingsurrogatemodelsfortheFEandtheCADmodels.Themodelsarebrieflypresentedbelow.2.1HighLevelCADTemplateGeometryModelTraditionally,parametricCADismainlyfocusedonmorphologicalmodificationsofthegeometry.However,thereisalimittomorphologicalparameterizationasfollows:?Thegeometriescannotberadicallymodified.?Increasedgeometriccomplexitygreatlyincreasesparameterizationcomplexity.ThegeometrymodeloftherobotisgeneratedwithpresavedHLCts,createdinCATIAV5.Thesearetopologicallyinstantiatedwithuniqueinternaldesignvariables.Topologicalparameterizationallowsdeletion,modification,andadditionofgeometricelementswhichleadstoamuchgreaterdesignspacecaptured.ThreetypesofHLCtsareusedtodefinetheindustrialrobottopologically;DatumHLCtwhichincludeswireframereferencesrequiredforplacementfortheActuatorHLCTsandStructureHLCts,asseenFig.2.Fig.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.Fig.3ThehighlevelCADtemplateinstantiationprocessSinceitispossibletocreatenewHLCtsintheutilizedCADtool,theusersarenotforcedtome