制造专业毕业设计外文翻译柔性制造系统的发展运用在实际制造中的范例.docx

制造专业毕业设计外文翻译柔性制造系统的发展运用在实际制造中的范例.docx

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制造专业毕业设计外文翻译柔性制造系统的发展运用在实际制造中的范例

DevelopmentofFlexibleManufacturingSystemusingVirtualManufacturingParadigm

Sung-ChungKim*andKyung-HyunChoi

Schoolofmechanicalengineering,ChungbukNationalUniversity,Cheongju,SouthKorea,

Schoolofmechanicalengineering,ChejuNationalUniversity,Cheju,SouthKorea

ABSTRACT

TheimportanceofVirtualManufacturingSystemisincreasingintheareaofdevelopingnewmanufacturingprocesses,implementingautomatedworkcells,designingplantfacilitylayoutsandworkplaceergonomics.Virtualmanufacturingsystemisacomputersystemthatcangeneratethesameinformationaboutmanufacturingsystemstructure,states,andbehaviorsasisobservedinarealmanufacturing.Inthisresearch,avirtualmanufacturingsystemforflexiblemanufacturingcells（VFMC）,（whichisausefultoolforbuildingComputerIntegratedManufacturing（CIM）,）hasbeendevelopedusingobject-orientedparadigm,andimplementedwithsoftwareQUEST/IGRIP.Threeobjectmodelsusedinthesystemaretheproductmodel,thefacilitymodel,andtheprocessmodel.Theconcretebehaviorsofaflexiblemanufacturingcellarerepresentedbythetask-orienteddescriptiondiagram,TID.Anexamplesimulationisexecutedtoevaluateapplicabilityofthedevelopedmodels,andtoprovethepotentialvalueofvirtualmanufacturingparadigm.

KeyWords:

FMS,virtualmanufacturingsystem,CIM,object-orientedparadigm,TID

Recenttrendsinmanufacturingsystems,suchastheneedforcustomizedproductsbysmallbatchesandforfastproductrenewalrates,havebeendemandingnewparadigmsinmanufacturing.Therefore,themodernmanufacturingsystemsareneededtobeadaptable,andhavethecapabilitytoreconfigureorselfconfiguretheirownstructure.FlexibleManufacturingCells（FMCs）aregenerallyrecognizedasthebestproductivitytoolforsmalltomediumbatchmanufacturing,andarealsobasicunittoconstructashopfloorwhichisanimportantlevefordevelopingcomputerintegratedmanufacturing（CIM）.However,duetoitscomplexity,themodelingandoperationmethodologyrelatedtoFMCshouldbeverifiedbeforeimplementation.

Asoneofapproachestotheserequirements,VirtualManufacturing（VM）approachhasbeenintroduced,andknownasaeffectiveparadigmforgeneratingamodelofmanufacturingsystemsandsimulatingmanufacturingprocessesinsteadoftheiroperationsintherealworld.VMpursuestheinformationalequivalencewithrealmanufacturingsystems.Therefore,theconceptofVirtualManufacturingSystemisexpectedtoprovidedramaticbenefitsinreducingcycletimes,manufacturingandproductioncosts,andimprovingcommunicationsacrossglobalfacilitiestolaunchnewproductsfaster,improveproductivityandreduceoperationscostsforexistingproductshop[1,2].

Withanobject-orientedparadigm,computer-basedtechnologiessuchasvirtualprototypingandvirtualfactoryareemployedasabasicconceptfordevelopingthemanufacturingprocesses,includingthelayoutoftheoptimalfacility,toproduceproducts.Virtualprototypingisaprocessbywhichadvancedcomputersimulationenablesearlyevaluationofnewproductsormachinesconceptwithoutactuallyfabricatingphysicalmachinesorproducts.Bodner,etal.,[3]concentratedonthedecisionproblemsassociatedwithindividualmachinesthatassembleelectroniccomponentsontoprintedcircuitboards（PCBs）.Virtualfactoryisarealistic,highlyvisual,3Dgraphicalrepresentationofanactualfactoryfloorwiththerealworldcomplexitylinkedtotheproductioncontrollingsystemandtherealfactory.Virtualfactoriesareincreasinglyusedwithinmanufacturingindustriesasrepresentationsofphysicalplants,forexample,VirtualWorksystemforrepresentationofshopfloorfactory[4].

Despiteitsbenefitsandapplicability,VMsystemsshoulddealwithanumberofmodelsofvarioustypesandrequirealargeamountofcomputationforsimulatingbehaviorofequipmentonashopfloor.Tocopewiththiscomplexityinmanufacturing,itisnecessarytointroduceopensystemarchitectureofmodelingandsimulationforVMsystems.

Inthispaper,threemodels,whichareproduct,device,andprocessmodelswillbeaddressed.EspeciallyprocessmodelforFMCwillbeemphasizedusingQUEST/IGRIPasanimplementationissue.Theopensystemarchitectureconsistsofwell-formalizedmodulesformodelingandsimulationthathavecarefullydecomposedfunctionsandwell-definedinterfacewithothermodules.

2.Conceptofvirtualmanufacturing

VirtualManufacturingSystemisacomputermodelthatrepresentsthepreciseandwholestructureofmanufacturingsystemsandsimulatestheirphysicalandlogicalbehaviorinoperation,aswellasinteractingwiththerealmanufacturingsystem.Itsconceptisspecifiedasthemodelofpresentorfuturemanufacturingsystemswithallproducts,processes,andcontroldata.Beforeinformationandcontroldataareusedintherealsystem,theirverificationisperformedwithinvirtualmanufacturingenvironment.Inaddition,itsstatusandinformationisfedbacktothevirtualsystemfromtherealsystem.

Virtualenvironmentswillprovidevisualizationtechnologyforvirtualmanufacturing.Thevirtualprototypeisanessentialcomponentinthevirtualproductlifecycle,whilethevirtualfactorycatersforoperationsneededforfabricatingproducts.Therefore,thedevelopmentsintheareaofvirtualprototypingandvirtualfactorywillenhancethecapabilitiesofvirtualmanufacturing.

Themajorbenefitofavirtualmanufacturingisthatphysicalsystemcomponents（suchasequipmentandmaterials）aswellasconceptualsystemcompvonents（e.g.,processplansandequipmentschedules）canbeeasilyrepresentedthroughthecreationofvirtualmanufacturingentitiesthatemulatetheirstructureandfunction.Theseentitiescanbeaddedtoorremovedfromthevirtualplantasnecessarywithminimalimpactonothersystemdata.Thesoftwareentitiesofthevirtualfactoryhaveahighcorrespondencewithrealsystemcomponents,therebylendingvaliditytosimulationscarriedoutinthevirtualsystemmeanttoaiddecision-makersintherealsystem.

Forvirtualmanufacturing,threemajorparadigmshavebeenproposed,suchasDesign-centeredVM,Production-centeredVM,andControl-centeredVM.Thedesign-centeredVMprovidesanenvironmentfordesignerstodesignproductsandtoevaluatethemanufacturabilityandaffordabilityofproducts.Theresultsofdesign-centeredVMincludetheproductmodel,costestimate,andsoforth.Thus,potentialproblemswiththedesigncanbeidentifiedanditsmeritcanbeestimated.Inordertomaintainthemanufacturingproficiencywithoutactualbuildingproducts,production-centeredVMprovidesanenvironmentforgeneratingprocessplansandproductionplans,forplanningresourcerequirements（newequipmentpurchase,etc.）,andforevaluatingtheseplans.Thiscanprovidemoreaccuratecostinformationandschedulesforproductdelivery.Byprovidingthecapabilitytosimulateactualproduction,control-centeredVMofferstheenvironmentforengineerstoevaluateneworrevisedproductdesignswithrespecttoshopfloorrelatedactivities.Control-centeredVMprovidesinformationforoptimizingmanufacturingprocessesandimprovingmanufacturingsystems.

ThevirtualmanufacturingapproachinthispaperisclosetoControl-centeredVM.Fig.1illustratestheviewpointofthefunctionalmodelofthevirtualflexiblemanufacturingcell.SincetheactivityExecuterealmanufacturingsystemsdepictsamodelofrealfactory,itpossiblyreplacesrealfactory.Allmanufacturingprocessesexceptphysicalelementsofvirtualmanufacturing,suchasdesign,processplanning,scheduling,areincludedintheactivityOperationofVirtualfactory.TheactivityExecutesimulationforvirtualfactoryisaseparatesimulationmodelofVMsystem.Withthisvirtualfactory,parameters（e.g,utilization,operationtime,etc.,）associatedwithoperatingaflexiblemanufacturingcellaresimulated.Andtheseresultscanprovidethepossibilityofcontrollingmanufacturingprocessesandpredictingpotentialproblemsintherealmanufacturing.

3.Objectmodelingforvirtualflexiblemanufacturingcells

Object-orientedtechnologymayprovideapowerfulrepresentationandclassificationtoolsforavirtualflexiblemanufacturingcell.Itmayalsoprovideacommonplatformfortheinformationsharingbetweensub-modules,andprovidearicherwaytostore/retrieve/modifyinformation,knowledgeandmodelsandreusethem.Inthecontextofanobjectorientedapproach,amodelissimplyanabstraction,orarepresentationofanobjectsorprocess.

VFMCrequiresarobustinformationinfrastructurethatcomprisesrichinformationmodelsforproducts,processesandproductionsystems.AsshowninFig.2,threemodels,thatisproductmodel,facilitymodel,andprocessmodel,aredevelopedforvirtualflexiblemanufacturingcells.Aproductmodelisagenericmodelusedforrepresentingalltypesofartifacts,whichappearintheprocessofmanufacturing.Itrepresentstargetproducts,whichincludeconceptualshapeinformationaswellasanalysismoduleforaspecification,productivity,andstrength.Afacilitymodelcontainsinformationaboutmachinesconsistedofavirtualflexiblemanufacturingcell.Byusingthemodel,innovativetoolingandmethodscanbeevaluatedwithoutthecostofphysicalmachineprototypesandfixturemock-ups.Aprocessmodelisusedforrepresentingallthephysicalprocessesthatarerequiredforrepresentingproductbehaviorand

manufacturingprocesses.

3.1Productmodel

Aproductmodelholdstheprocessandproductknowledgetoensurethecorrectfabricationoftheproductwithsufficientquality.Itactsasaninformationservertotheo