翻译—基于事例推理的夹具设计研究与应用.pdf

1APPLICATIONANDDEVELOPMENTOFOOOCASEBASEDREASONINGINFIXTUREDESIGNABSTRACTBASEDONTHECASEBASEDDESIGNINGCBDMETHODOLOGY,THEFIXTURESIMILARITYISINTWORESPECTSTHEFUNCTIONANDTHESTRUCTUREINFORMATIONTHEN,THECOMPUTERAIDEDFIXTUREDESIGNSYSTEMISCREATEDONCASEBASEDREASONINGCBR,INWHICHTHEATTRIBUTESOFTHEMAINFEATURESOFWORKPIECEANDSTRUCTUREOFFIXTUREASCASEINDEXCODEAREDESIGNEDFORTHERETRIEVEOFTHESIMILARCASES,ANDTHESTRUCTUREANDHIERARCHICALRELATIONOFCASELIBRARYARESETUPFORSTOREMEANWHILE,THEALGORITHMBASEDONTHEKNOWLEDGEGUIDEDINTHERETRIEVEOFTHESIMILARCASES,THESTRATEGYOFCASEADAPTATIONANDCASESTORAGEINWHICHTHECASEIDENTIFCATIONNUMBERISUSEDTODISTINGUISHFROMSIMILARCASESAREPRESENTEDTHEAPPLICATIONOFTHESYSTEMINSOMEPROJECTSIMPROVESTHEDESIGNEFFICIENCYANDGETSAGOODRESULTKEYWORDSKKKCASEBASEDREASONINGFIXTUREDESIGNCOMPUTERAIDEDDESIGNCADFIXTURESAREDEVICESTHATSERVEASTHEPURPOSEOFHOLDINGTHEWORKPIECESECURELYANDACCURATELY,ANDMAINTAININGACONSISTENTRELATIONSHIPWITHRESPECTTOTHETOOLSWHILEMACHININGBECAUSETHEFIXTURESTRUCTUREDEPENDSONTHEFEATUREOFTHEPRODUCTANDTHESTATUSOFTHEPROCESSPLANNINGINTHEENTERPRISE,ITSDESIGNISTHEBOTTLENECKDURINGMANUFACTURING,WHICHRESTRAINSTOIMPROVETHEEFFICIENCYANDLEADTIMEANDFIXTURE2DESIGNISACOMPLICATEDPROCESS,BASEDONEXPERIENCETHATNEEDSCOMPREHENSIVEQUALITATIVEKNOWLEDGEABOUTANUMBEROFDESIGNISSUESINCLUDINGWORKPIECECONFIGURATION,MANUFACTURINGPROCESSESINVOLVED,ANDMACHININGENVIRONMENTTHISISALSOAVERYTIMECONSUMINGWORKWHENUSINGTRADITIONALCADTOOLSSUCHASUNIGRAPHICS,CATIAORPRO/E,WHICHAREGOODATPERFORMINGDETAILEDDESIGNTASKS,BUTPROVIDEFEWBENEFITSFORTAKINGADVANTAGEOFTHEPREVIOUSDESIGNEXPERIENCEANDRESOURCES,WHICHAREPRECISELYTHEKEYFACTORSINIMPROVINGTHEEFFICIENCYTHEMETHODOLOGYOFCASEBASEDREASONINGCBRADAPTSTHESOLUTIONOFAPREVIOUSLYSOLVEDCASETOBUILDASOLUTIONFORANEWPROBLEMWITHTHEFOLLOWINGFOURSTEPSRETRIEVE,REUSE,REVISE,ANDRETAIN1THISISAMOREUSEFULMETHODTHANTHEUSEOFANEXPERTSYSTEMTOSIMULATEHUMANTHOUGHTBECAUSEPROPOSINGASIMILARCASEANDAPPLYINGAFEWMODIFICATIONSSEEMSTOBESELFEXPLANATORYANDMOREINTUITIVETOHUMANSSOVARIOUSCASEBASEDDESIGNSUPPORTTOOLSHAVEBEENDEVELOPEDFORNUMEROUSAREAS24,SUCHASININJECTIONMOLDINGANDDESIGN,ARCHITECTURALDESIGN,DIECASTINGDIEDESIGN,PROCESSPLANNING,ANDALSOINFIXTUREDESIGNSUNUSEDSIXDIGITALSTOCOMPOSETHEINDEXCODETHATINCLUDEDWORKPIECESHAPE,MACHINEPORTION,BUSHING,THE1STLOCATINGDEVICE,THE2NDLOCATINGDEVICEANDCLAMPINGDEVICE5BUTTHESYSTEMCANNOTBEUSEDFOROTHERFIXTURETYPESEXCEPTFORDRILLFIXTURES,ANDCANNOTSOLVETHEPROBLEMOFSTORAGEOFTHESAMEINDEXCODETHATNEEDSTOBERETAINED,WHICHISVERYIMPORTANTINCBR61CONSTRUCTIONOFACASEINDEXAND3CASELIBRARY11CASEINDEXTHECASEINDEXSHOULDBECOMPOSEDOFALLFEATURESOFTHEWORKPIECE,WHICHAREDISTINGUISHEDFROMDIFFERENTFIXTURESUSINGALLOFTHEMWOULDMAKETHEOPERATIONINCONVENIENTBECAUSETHEFORMSOFTHEPARTSAREDIVERSE,ANDTHETECHNOLOGYREQUIREMENTSOFMANUFACTUREINTHEENTERPRISEALSODEVELOPCONTINUOUSLY,LOTSOFFEATURESUSEDASTHECASEINDEXWILLMAKETHESEARCHRATESLOW,ANDTHEMAINFEATUREUNIMPORTANT,FORTHEREASONTHATTHERELATIVEWEIGHTWHICHISALLOTTEDTOEVERYFEATUREMUSTDIMINISHANDONTHEOTHERHAND,ITISHARDTOINCLUDEALLTHEFEATURESINTHECASEINDEXTHEREFORE,CONSIDERINGTHEPRACTICALITYANDTHEDEMANDOFRAPIDDESIGN,THECASEINDEXINCLUDESBOTHTHEMAJORFEATUREOFTHEWORKPIECEANDTHESTRUCTUREOFFIXTURETHECASEINDEXCODEISMADEUPOF16DIGITS13DIGITSFORCASEFEATURESAND3DIGITSFORCASEIDENTIFICATIONNUMBERTHEFIRST13DIGITSREPRESENT13FEATURESEACHDIGITISCORRESPONDINGTOANATTRIBUTEOFTHEFEATURE,WHICHMAYBEONEOF“”,“”,“1”,“2”,“A”,“B”,“Z”,ETCINWHICH,“”MEANSANYONE,“”UNCERTAIN,“0”NOTHINGTHESYSTEMRULESFIXTURETYPE,WORKPIECESHAPE,LOCATINGMODELCANNOTBE“”OR“”WHENTHESYSTEMISDESIGNED,THEATTRIBUTEINFORMATIONOFTHETHREEITEMSDOESNOTHAVETHESEOPTIONS,WHICHMEANSTHECERTAINATTRIBUTEMUSTBESELECTEDTHELASTTHREEDIGITSARETHECASEIDENTIFICATIONNUMBER,WHICHMEANSTHE13DIGITSOFTHECASEFEATUREARETHE4SAME,ANDTHENUMBEROFTHESETHREEDIGITSISUSEDFORDISTINGUISHINGTHEMTHESYSTEMALSORULES“000”ISAPROTOTYPECASE,WHICHISUSEDFORRETRIEVAL,ANDOTHERCASESARE“001”,“002”,WHICHAREUSEDFORREFERENCECASESTOBESEARCHEDBYDESIGNERSIFOCCASIONALLYONEOFTHEMNEEDSTOBECHANGEDASTHEPROTOTYPECASE,FIRSTITMUSTBEREQUIREDTOAPPLYTOCHANGETHEONETO“000”,ANDTHEFORMERISCHANGEDTOREFERENTIALCASEAUTOMATICALLYTHECONSTRUCTIONOFTHECASEINDEXCODEISSHOWNINFIG112CASELIBRARYTHECASELIBRARYCONSISTSOFLOTSOFPREDEFINEDCASESCASEREPRESENTATIONISONEOFTHEMOSTIMPORTANTISSUESINCASEBASEDREASONINGSOCOMPOUNDINGWITHTHEINDEXCODE,13HIERARCHICALFORMOFCASETHESTRUCTURESIMILARITYOFTHEFIXTUREISREPRESENTEDASTHEWHOLEFIXTURESIMILARITY,COMPONENTSSIMILARITYANDCOMPONENTSIMILARITYSOTHEWHOLEFIXTURECASELIBRARY,COMPONENTSCASELIBRARY,COMPONENTCASELIBRARYOFFIXTUREAREFORMEDCORRESPONDINGLYUSUALLYDESIGNINFORMATIONOFTHEWHOLEFIXTUREISCOMPOSEDOFWORKPIECEINFORMATIONANDWORKPIECEPROCEDUREINFORMATION,WHICHREPRESENTTHEFIXTURESATISFYINGTHESPECIFICALLYDESIGNINGFUNCTIONDEMANDTHEWHOLEFIXTURECASEISMADEUPOFFUNCTIONCOMPONENTS,WHICHAREDESCRIBEDBYTHEFUNCTIONCOMPONENTSNAMESANDNUMBERSTHECOMPONENTSCASEREPRESENTSTHEMEMBERSFUNCTIONCOMPONENTAND5OTHERSTRUCTURECOMPONENTS，MAINDRIVENPARAMETER,THENUMBER,ANDTHEIRCONSTRAINRELATIONSTHECOMPONENTCASETHELOWESTLAYEROFTHEFIXTUREISTHESTRUCTUREOFFUNCTIONCOMPONENTANDOTHERCOMPONENTSINTHEMODERNFIXTUREDESIGNTHEREARELOTSOFPARAMETRICSTANDARDPARTSANDCOMMONNONSTANDARDPARTSSOTHECOMPONENTCASELIBRARYSHOULDRECORDTHESPECIFICATIONPARAMETERANDTHEWAYINWHICHITKEEPSTHEM2STRATEGYOFCASERETRIEVALINTHECASEBASEDDESIGNOFFIXTURES,THEMOSTIMPORTANTTHINGISTHERETRIEVALOFTHESIMILARITY,WHICHCANHELPTOOBTAINTHEMOSTSIMILARCASE,ANDTOCUTDOWNTHETIMEOFADAPTATIONACCORDINGTOTHEREQUIREMENTOFFIXTUREDESIGN,THESTRATEGYOFCASERETRIEVALCOMBINESTHEWAYOFTHENEARESTNEIGHBORANDKNOWLEDGEGUIDEDTHATIS,FIRSTSEARCHONDEPTH,THENONBREADTHTHEKNOWLEDGEGUIDEDSTRATEGYMEANSTOSEARCHONTHEKNOWLEDGERULEFROMROOTTOTHEOBJECT,WHICHISFIRSTLYSEARCHEDBYTHEFIXTURETYPE,THENBYTHESHAPEOFTHEWORKPIECE,THIRDLYBYTHELOCATINGMETHODFOREXAMPLE,IFTHECASEINDEXCODEINCLUDESTHEMILLINGFIXTUREOFFIXTURETYPE,THESEARCHISJUSTFORALLMILLINGFIXTURES,THENFORBOXOFWORKPIECESHAPE,THETHIRDFOR1PLANE2PINEOFLOCATINGMETHODIFTHEREISNOMATCHOFIT,THENTHESEARCHSTOPSONDEPTH,ANDRETURNSTOTHEUPPERLAYER,ANDRETRIEVESALLTHERELATIVECASESONBREADTHRETRIEVALALGORITHMS1ACCORDINGTOTHECASEINDEXINFORMATIONOFFIXTURECASELIBRARY,SEARCHTHERELEVANTCASELIBRARY2MATCHTHECASEINDEXCODEWITHTHECODEOFEACHCASEOFTHECASELIBRARY,6ANDCALCULATETHEVALUEOFTHESIMILARITYMEASURE3SORTTHEORDEROFSIMILARITYMEASURE,THEBIGGESTVALUE,WHICHISTHEMOSTANALOGICALCASESIMILARITYBETWEENTWOCASESISBASEDONTHESIMILARITYBETWEENTHETWOCASESFEATURESTHECALCULATIONOFSIMILARITYMEASUREDEPENDSONTHETYPEOFTHEFEATURETHEVALUEOFSIMILARITYCANBECALCULATEDFORNUMERICALVALUES,FOREXAMPLE,COMPAREWORKPIECEWITHTHEWEIGHTOF50KGAND20KGTHEVALUECANALSOBECALCULATEDBETWEENNONNUMERICALVALUES,FOREXAMPLE,NOWTHEFIRST13DIGITSINDEXCODEISALLNONNUMERICALVALUESTHESIMILARITYMEASUREOFAFIXTUREISCALCULATEDASFOLLOWSWHERESISTHESIMILARITYMEASUREOFCURRENTFIXTURE,NISTHENUMBEROFTHEINDEXFEATURE,ISTHEWEIGHTOFEACHFEATURE,ISTHESIMILARITYMEASUREOFTHEATTRIBUTEOFTHEI2THFEATUREWITHTHEATTRIBUTEOFRELATIVEFEATUREOFTHEJTHCASEINTHECASELIBRARYATTHESAMETIME,THEVALUECOUNTSASFOLLOWSWHEREISTHEVALUEOFTHEINDEXATTRIBUTEOFTHEITHFEATURE,ANDIS7THEVALUEOFATTRIBUTEOFTHERELATIVEITHFEATUREOFTHEJTHCASEINCASELIBRARYSOTHEREARETWOMETHODSTOSELECTTHEANALOGICALFIXTUREONEISTOSETTHEVALUEIFTHEVALUESOFSIMILARITYMEASUREOFCURRENTCASESWERELESSTHANAGIVENVALUE,THOSECASESWOULDNOTBESELECTEDASANALOGICALCASESWHENTHECASELIBRARYISINITIALLYSETUP,ANDTHEREAREONLYAFEWCASES,THEVALUECANBESETSMALLERIFTHEREARELOTSOFANALOGICALCASES,THEVALUESHOULDGETLARGERTHEOTHERISJUSTTOSETTHENUMBEROFTHEANALOGICALCASESSUCHAS10,WHICHISTHELARGESTVALUEOFSIMILARITYMEASUREFROMTHESORTEDORDER3CASEADAPTATIONANDCASESTORAGE31CASEADAPTATIONTHEMODIFICATIONOFTHEANALOGICALCASEINTHEFIXTUREDESIGNINCLUDESTHEFOLLOWINGTHREECASES1THESUBSTITUTIONOFCOMPONENTSANDTHECOMPONENT2ADJUSTINGTHEDIMENSIONOFCOMPONENTSANDTHECOMPONENTWHILETHEFORMREMAINS3THEREDESIGNOFTHEMODELIFTHECOMPONENTSANDCOMPONENTOFTHEFIXTUREARECOMMONOBJECTS,THEYCANBEEDITED,SUBSTITUTEDANDDELETEDWITHTOOLS,WHICHHAVEBEENDESIGNED32CASESTORAGEBEFORESAVINGANEWFIXTURECASEINTHECASELIBRARY,THEDESIGNERMUSTCONSIDERWHETHERTHESAVINGISVALUABLEIFTHECASEDOESNOTINCREASETHEKNOWLEDGEOFTHESYSTEM,ITISNOTNECESSARYTOSTOREITINTHECASELIBRARYIFITISVALUABLE,THENTHEDESIGNERMUSTANALYZEITBEFORESAVINGITTOSEEWHETHERTHECASEISSTOREDASAPROTOTYPECASEORASREFERENCECASEA8PROTOTYPECASEISAREPRESENTATIONTHATCANDESCRIBETHEMAINFEATURESOFACASEFAMILYACASEFAMILYCONSISTSOFTHOSECASESWHOSEINDEXCODESHAVETHESAMEFIRST13DIGITSANDDIFFERENTLASTTHREEDIGITSINTHECASELIBRARYTHELASTTHREEDIGITSOFAPROTOTYPECASEAREALWAYS“000”AREFERENCECASEBELONGSTOTHESAMEFAMILYASTHEPROTOTYPECASEANDISDISTINGUISHEDBYTHEDIFFERENTLASTTHREEDIGITSFROMTHECONCEPTTHATHASBEENEXPLAINED,THEFOLLOWINGSTRATEGIESAREADOPTED1IFANEWCASEMATCHESANYEXISTINGCASEFAMILY,ITHASTHESAMEFIRST13DIGITSASANEXISTINGPROTOTYPECASE,SOTHECASEISNOTSAVEDBECAUSEITISREPRESENTEDWELLBYTHEPROTOTYPECASEORISJUSTSAVEDASAREFERENCECASETHELAST3DIGITSARENOT“000”,ANDNOTTHESAMEWITHOTHERSINTHECASELIBRARY2IFANEWCASEMATCHESANYEXISTINGCASEFAMILYANDISTHOUGHTTOBEBETTERATREPRESENTINGTHISCASEFAMILYTHANTHEPREVIOUSPROTOTYPECASE,THENTHEPROTOTYPECASEISSUBSTITUTEDBYTHISNEWCASE,ANDTHEPREVIOUSPROTOTYPECASEISSAVEDASAREFERENCECASE3IFANEWCASEDOESNOTMATCHANYEXISTINGCASEFAMILY,ANEWCASEFAMILYWILLBEGENERATEDAUTOMATICALLYANDTHECASEISSTOREDASTHEPROTOTYPECASEINTHECASELIBRARY4PROCESSOFCBRINFIXTUREDESIGNACCORDINGTOTHECHARACTERISTICSOFFIXTUREDESIGN,THEBASICINFORMATIONOFTHEFIXTUREDESIGNSUCHASTHENAMEOFFIXTURE,PART,PRODUCTANDTHEDESIGNER,ETCMUSTBEINPUTFIRSTTHENTHEFIXTUREFILEISSETUPAUTOMATICALLY,INWHICHALL9COMPONENTSOFTHEFIXTUREAREPUTTOGETHERTHENTHEMODELOFTHEWORKPIECEISINPUTORDESIGNEDTHEDETAILEDINFORMATIONABOUTTHEWORKPIECEISINPUT,THECASEINDEXCODEISSETUP,ANDTHENTHECBRBEGINSTOSEARCHTHEANALOGICALCASES,RELYINGONTHESIMILARITYMEASURE,ANDTHEMOSTANALOGICALCASEISSELECTEDOUTIFNEEDED,THECASEISADAPTEDTOSATISFYTHECURRENTDESIGN,ANDRESTOREDINTOTHECASELIBRARYTHEFLOWCHARTOFTHEPROCESSISSHOWNINFIG35ILLUSTRATINGFORFIXTUREDESIGNBYCBRTHISISAWORKPIECESEEFIG4ITSMATERIALIS45STEELITSNAMEISSEATITSSHAPEISBLOCK,ANDTHEPRODUCTBATCHSIZEISMIDDLE,ETCAFIXTUREISTURNINGFIXTURETHATSERVESTOTURNTHEHOLE,WHICHNEEDSTOBEDESIGNEDTHEVALUEOFFEATURE,ATTRIBUTE,CASEINDEXCODEANDWEIGHTOFTHEWORKPIECEISSHOWNINTAB210THROUGHSEARCHING,ANDCALCULATINGTHESIMILARITY,THECASEINDEXCODEOFTHEMOSTSIMILARCASEIS19325513321402000,ANDTHEDETAILEDINFORMATIONISSHOWNINTAB3THESIMILARITYISCALCULATEDASFOLLOWSSOTHEVALUEOFSIMILARITYMEASUREOFTHEFIXTUREWHICHNEEDSTOBEDESIGNEDWITHTHEMOSTANALOGICALCASEINCASELIBRARYIS0806,ANDTHESTRUCTU