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KBE-basedstampingprocesspathsgeneratedforautomobilepanelsJinqiaoZheng.YilinWang.ZhigangLiAbstract:Asautomobilebodypanelsareonekindofsheetmetalpartwithgroupsoffreeformsurfaces,theprocessplanningismorecomplicatedthancommonsheetmetalstampingtoimplodeeffectivelyandpractically.BasedonKBE,newframeworkshavebeenpresentedasintelligentmastermodelatthesystemlevelandasproceduremodelattheactivitylevel.Inaccordancewiththeseframeworks,anintelligentCAPPsystemhasbeenspecificallydeveloped.Basedonfeaturetechnology,featureshavebeenextractedandrepresentedbytheobject-orientedmethod.Stampingfeaturesandtheirparametershavebeendefinedandextractedbasedonfeaturetechnologyandstampingprocessrules.Thewholeproductknowledgehasbeenrepresentedbyframeswhichdirectlymaptoobjects(orfeatures)intheobject-orientedsense.Relevantappropriateoperationsfeatureshavebeenassignedtostampingfeaturesofaproductbasedonfeature-operationcriteria,parametersofthestampingfeatureandtheircorrelativity.Thisassignmentisadecision-makingactivityusingasetofruleswithadecision-makingtreeandmodel-basedreasoningmethods.Withknowledgebetweenoperations,suchasoperationsorderconstraint(do-after)andoperationscombinationconstraint,processpathshavebeenimprovedbasedonrelevantintelligentreasoningmethods.Basedontherelationships(preferred-to)betweenprocessesandmachines/dies,thestructureofdieandmachineforeachprocesscanbeidentified,sincetheprocessroutehasbeendetermined.Inthisstampingprocessplanning,theprocedureandinformationhavebeencontrolledbyaprocesscontrolstructurethatisassociativeandintegrated.1IntroductionRecently,researchonthecomputer-aidedprocessplanning(CAPP)systemforsheetmetalhasbeenwidelyreported.Parketal.[1]constructedanautomatedprocessplanningsystemforaxsymmetricdeepdrawingproducts.Tessa[2]andKangandPark[3]presentedagrouptechnologyandmodularitytoconstructaCAPPsystemforprocesssequencedesigninanexpertsystemfornon-axsymmetricdeepdrawingproductswithellipticalshape.Gaoetal.[4]developedanadvancedsoftwaretoolsetusedfortheautomationofsheetmetalfabricationplanningforaircraftcomponents.ZussmanandHorsch[5]proposedamotionplanningapproachforrobot-assistedmultiple-bentpartsbasedonC-spaceandapotentialfield.WangandBourne[6]proposedanautomaticprocessplanningsystemwiththefeatureswellinvestigatedandtheproductionplansresearchedwithnear-minimummanufacturingcosts.DeVinetal.[7,8]developedasheet-metalCAPPsystemcalledPART-S,whichintegratescutting,nesting,bendingandweldingprocessesforbendingsequences.Streppeletal.[9]showedtheambiguityofconventionaltolerancesandpresentedamethodwhichreplacesconventionaltoleranceswithgeometricaltolerancesforprocessplanninginsmallbatchsheetmetalpartmanufacturing.Amoraletal.[10]proposedamethodwhichgeneratedfeasiblebendingsequencesofasheetmetalparthandledbyarobot,anddiscussedthedeterminationofthebestgraspingpositionsandrepositions.AomuraandKoguchi[11]pro-posedamethodtogeneratebendingsequencesofasheetmetalparthandledbyarobot.LiaoandWang[12]proposedanevolutionarypath-planningapproachforrobot-assistedhandlingofsheetmetalpartsinbending.Luttersetal.[13]developedagenericarchitectureforcomputeraidedprocessplanningbasedoninformationmanagementforsheetmetalmanufacturinginasmallbatchpartenvironment.KumarandRajotia[14]hadproposedamethodofschedulinganditsintegrationwithCAPP,sothaton-lineprocessplanscanbegeneratedtakingintoaccounttheavailabilityofmachinesandalternativeroutes.Thecontentsabovearemainlyforprocessparametercalculating,path-planningandsomesketchmapofwork-piecesforspecifictypesofsheetmetal,suchasaxis-metricandnon-axsymmetricdeepdrawings,complexbandingsandsheerings,andsoon.Theautomobilebodypanelisonekindofsheetmetalpart,whichiscomplicatedinshape,withgroupsoffreeformsurfaces,alargefigureinsizeandisalwaysmanufacturedbystampingprocesses.Automobilepanelscanbeconsideredasacombinationofsomecommonstamping,suchasirregulardrawing,flanging/bending,trimmingandpiercing,etc.Theprocessplanningofthesepanelsismorecomplicatedthancommonsheetmetalstamping,whichisgenerallydependentonengineersexperiencetocomplete.Itisbelievedthattheprocesspathplanforautomobilepanelsisrequisiteandacquirable.Inessence,thestampingprocesspathforautomobilepanelsistodeterminethenecessaryformingprocessesandtheirsequencesinordertoproduceaparticularparteconomicallyandcompetitively.Processpathsgenerationisadecision-makingprocess.Decisionsonstampingoperationsforaparticularfeaturehavetobeformedonvariousindependentconditionssuchaswhichoperationshouldbeperformedwithwhichdieandtoolsandunderwhatformingparameters.ACAPPsystemfortheseshouldbeanintegratedenvironmenttodealwithknowledgetoreducethedependenceonengineersorexperts,andrealizetheprocessplanningwithscientism.Thus,knowledgebasedengineering(KBE)isappliedtoadvancethestampingCAPPsystemforautomobilepanels,andeventoimprovethecompetitivenessfortheautomobileindustry.ThispaperisparticularlyconcernedwiththeconstructioninvolvedwithdevelopingaCAPPsystembasedonKBE.2KBEinCAPPsystemforstamping2.1KBEKnowledgebasedengineering(KBE)isoneinnovativemethodofartificialintelligenceforengineeringdesigndev