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1、与机械有关的外文及翻译MultidisciplinaryDesignOptimizationofModularIndustrialRobotsbyUtilizingHighLevelCADTemplates1、IntroductionInthedesignofcomplexandtightlyintegratedengineeringproducts,itisessentialtobeabletohandleinteractionsbetweendifferentsubsystemsofmultidisciplinarynature1.Toachieveanoptimaldesign,apro
2、ductmustbetreatedasacompletesysteminsteadofdevelopingsubsystemsindependently2.MDOhasbeenestablishedasaconvincingconcurrentdesignoptimizationtechniqueindevelopmentofsuchcomplexproducts3,4.Furthermore,ithasbeenpointedoutthat,regardlessofdiscipline,basicallyallanalysesrequireinformationthathastobeextra
3、ctedfromageometrymodel5. Hence,accordingtoBow-cutt1,inordertoenableintegrateddesignanalysisandoptimizationitisofvitalimportancetobeabletointegrateanautomatedparametricgeometrygenerationsystemintothedesignframework.Theautomatedgeometrygenerationisakeyenablerforso-calledgeometry-in-the-loop6multidisci
4、plinarydesignframeworks,wheretheCADgeometriescanserveasframeworkintegratorsforotherengineeringtools.Toeliminatenoncreativework,methodsforcreationandautomaticgenerationofHLCthavebeensuggestedbyTarkian7.TheprincipleofhighHLCtsissimilartohighlevelprimitives(HLP)suggestedbyLaRoccaandvanTooren8,withtheex
5、ceptionthatHLCtsarecreatedandutilizedinaCADenvironment.Otherwise,thebasicsofbothHLPandHLCtcan,assuggestedbyLaRocca,becomparedtoparametricLEGOVRblockscontainingasetofdesignandanalysisparameters.Theseareproducedandstoredinlibraries,givingengineersoracomputeragentthepossibilitytofirsttopologicallyselec
6、tthetemplatesandthenmodifythemorphology,meaningtheshape,ofeachtemplateparametrically.2、MultidisciplinaryDesignFrameworkMDOisa“systematicapproachtodesignspaceexploration”17,theimplementationofwhichallowsthedesignertomaptheinterdisciplinaryrelationsthatexistinasystem.Inthiswork,theMDOframeworkconsists
7、ofageometrymodel,afiniteelement(FE)model,adynamicmodelandabasiccostmodel.Thegeometrymodelprovidestheanalysistoolswithgeometricinput.Thedynamicmodelrequiresmasspropertiessuchasmass,centerofgravity,andinertia.TheFEmodelneedsthemeshedgeometryoftherobotaswellastheforceandtorqueinteractionsbasedonresults
8、ofdynamicsimulations.Highfidelitymodelsrequireanextensiveevaluationtimewhichhasbetakenintoaccount.ThisshortcomingisaddressedbyapplyingsurrogatemodelsfortheFEandtheCADmodels.Themodelsarebrieflypresentedbelow.2.1HighLevelCADTemplateGeometryModelTraditionally,parametricCADismainlyfocusedonmorphological
9、modificationsofthegeometry.However,thereisalimittomorphologicalparameterizationasfollows:?Thegeometriescannotberadicallymodified.?Increasedgeometriccomplexitygreatlyincreasesparameterizationcomplexity.ThegeometrymodeloftherobotisgeneratedwithpresavedHLCts,createdinCATIAV5.Thesearetopologicallyinstan
10、tiatedwithuniqueinternaldesignvariables.Topologicalparameterizationallowsdeletion,modification,andadditionofgeometricelementswhichleadstoamuchgreaterdesignspacecaptured.ThreetypesofHLCtsareusedtodefinetheindustrialrobottopologically;DatumHLCtwhichincludeswireframereferencesrequiredforplacementforthe
11、ActuatorHLCTsandStructureHLCts,asseenFig.2.Fig.2Anindustrialrobot(left)andamodularindustrialrobot(right)ThenamesofthereferencesthatmustbeprovidedforeachHLCtinstantiationarestoredintheknowledgebase(seeAppen-dixA.4),whichissearchedthroughbytheinferenceengine.InAppendixA,pseudocodeexamplesdescribeshowt
12、hereferencesareretrievedandhowtheyarestoredintheknowledgebase.Theprocessstartsbytheuserdefiningthenumberofdegreesoffreedom(DOF)oftherobot(seeFig.3)andisrepeateduntilthenumberofaxis(i)isequaltotheuserdefinedDOF.InordertoinstantiatethefirstStructureHLCt,twoDatumandtwoactuatorinstancesareneeded.Referen
13、cesfromthetwoDatuminstanceshelporientingthestructureinspace,whilethegeometriesoftheactuatorinstances,atbothendsofthelink,areusedtoconstructtheactuatorattachments,asseeninFigs.2and3.Fortheremaininglinks,onlyonenewinstanceofbothdatumandactuatorHLCtsarerequired,sincethedatumandactuatorinstancesfromadja
14、centlinksarealreadyavailable.AppendixA.2showsapseudocodeexampleofaninstantiationfunction.ThefirstinstantiateddatumHLCtisdefinedwithreferencetotheabsolutecoordinatesystem.TheremainingdatumHLCtinstancesareplacedinasequentialorder,wherethecoordinatesystemofpreviousinstancesisusedasreferencefordefiningthepositioninspaceaccordingtouserinputs(seealsoAppendixA.3).Furthermore,thetypeofeachactuatorandstructureinstanceisuserdefined.Fig.3ThehighlevelCADtemplateinstantiationprocessSinceitispossibletocreatenewHLCtsintheutilizedCADtool,theusersarenotforcedtome
