自動夾具中英文對照外文翻譯文獻

中英文對照外文翻譯文獻(文檔含英文原文和中文翻譯)AUTOMATICFIXTURESYNTHESISIN3DKamenPenevProgrammableAutomationLaboratoryComputerScienceDepartmentandInstituteforRoboticsandIntelligentSystemsUniversityofSouthernCaliforniaLosAngeles,CA90089-0781 AristidesA.G.RequichaProgrammableAutomationLaboratoryComputerScienceDepartmentandInstituteforRoboticsandIntelligentSystemsUniversityofSouthernCaliforniaLosAngeles,CA90089-0781AbstractAfixtureisanarrangementoffixturingmodulesthatlocateandholdaworkpartduringamanufacturingoperation.Inthisworkwe.considerfixtureswithfrictionlesspointcontactsandpresentamethodforplacementofcontactpointsonanon-prismatic3Dworkpart.Itisanon-deterministic,potentialfieldalgorithmforcontactpointplacement.Themethodprovidesabasicframeworkfortheintegrationofheterogeneoushigh-levelfixturingagentsthroughaninterfacebasedonzonesofattractionandrepulsionontheworkpartboundary.Thealgorithmmayproduceredundantfixtures,andcanaugmentpartialsolutionstocompleteformclosurefixtures.1.IntroductionAfixtureisanarrangementoffixturingmodulesthatlocateandholdaworkpartduringamanufacturingoperation,suchasmachining,assemblyandinspection.Fixturingisofessentialimportancetoindustrialmanufacturingandconstitutesasignificantpartofallmanufacturingcosts.Therefore,fixturedesignautomationisveryimportant.Fixturedesigninvolvesagreatvarietyofconsiderations,suchasrestraint,deterministiclocation,loadability,andtoolaccessibility.Efficientalgorithmsthataddressthewholerangeoffixturingissuesforacomprehensivedomainofworkpartsdonotyetexist.Recently,BrostandPeterspublishedanalgorithm[Brost&Peters1996]thatextendstheearlierclassicworkofBrostandGoldberg[Brost&Goldberg,1994]tothe3Ddomain.Thisalgorithm,however,requiresverticalandhorizontalplanarsurfacestoconstituteasubstantialpartoftheworkpartboundary.Itgeneratesallpossiblefixturesandthenratesthemaccordinglytocertainmetrics.Thisiscomputationallyexpensive.Wagneretalpresentedanalgorithmthatusessevenmodularstrutsmountedinaboxtofixturepolyhedra[Wagneretal1995].Thisalgorithmisnotcompleteinthesensethatitcannoteffectivelyhandlecertaincases,suchasacubewithfacesparalleltothebox.Italsosuffersfromhighcomputationalcomplexity.WallackandCannysuggestedanothermethodwithan“enumerate-and-rate”flavor[Wallack&Canny1996].Itcanfixtureprismaticworkpartswithplanarandcylindricalverticalsurfaces.Ponceproposedanalgorithmthatutilizescurvatureeffectstocomputefixtureswithfourfingersforpolyhedralparts[Ponce96].Thereducednumberofcontactsshouldprovideforbettercomplexityofthisalgorithm,butthequalityoftheproducedfixturesseemstobeinferiortotheonesthatutilizemorecontactsandprovideclassicalformclosure.Inthispaperwepresentanewpotential-fieldalgorithmthatefficientlyproducesqualityfixturedesigns.Ouralgorithmworksforarbitraryworkpartsandprovidesconvenientuniversalmeansforrepresentingvariousfixturingrequirements.Thisalgorithmisadirectgeneralizationofthe2DpotentialfieldfixturingalgorithmofPenevandRequicha[Penev&Requicha1996].Weconsiderfixtureswithfrictionlesspointcontacts.Ithasbeenproventhatsevencontactsarenecessary.[Somoff,1900]andsufficient[Markenscoffetal,1990]toimmobilizeanyworkpartin3DFollowingaleast-commitmentstrategy,theprocessoffixturesynthesismaybeseparatedintothreestages–fixturingtaskanalysis,contactpointplacement,andfixturelayoutdesign.Inthefixturingtaskanalysisphasetheworkpartgeometryandmanufacturingprocessareanalyzedtoidentifyvariousparametersofthefixturingproblem,suchascuttingforces,inaccessibleorforbiddenareas,andalsotofindfeaturesthatmaybeusefulforapplyingfixturingdevices,suchasmachinedflatsurfaces,horizontalandverticalsurfaces,pairsofparallelsurfaces,pairsofperpendicularsurfaces,etc.FigureSEQFigure\*ARABIC1:ContactpointplacementInthecontactpointplacementphaseanumberofcontactpointsareplacedontheworkpartboundary(REF_Ref346884946Figure1),sothattheresultingconfigurationofcontactssatisfiestheconstraintsidentifiedintheanalysisphaseaswellascertainkinematicrequirementsthatmustbesatisfiedbyanyfixture,suchastotalrestraint.FigureSEQFigure\*ARABIC2:FromcontactpointconfigurationtofixturelayoutdesignInthelayoutdesignphase“towers”offixturingcomponentsarebuiltandplacedaroundtheworkpartsoastocontactthepartatthepointlocationscomputedinthecontactpointplacementphase.Forexample,acontactpointonahorizontalworkpartsurface(REF_Ref346884976Figure2a)mayleadtotheinstantiationofanoverheadclampthatcontactstheworkpartatthatparticularpoint(REF_Ref346884976Figure2b).Thisisadesign-for-functionproblemconstrainedbythesetofavailablefixturingmodulesandtheirparameters.Thesetofcontactpointsarethefunctionalspecificationandthefixturelayoutisaconfigurationofcomponentsthatachievesit.Inthisresearchwefocusoncontactpointplacementanditsintegrationwithpartandtaskanalysis.Anarrangementofcontactpointsmustsatisfycertainkinematicconditionsinordertobeabasisforagoodfixture.Inparticular,itmustprovideformclosure,deterministiclocation,clampingstability,detachabilityandloadability[Asada&By].Thealgorithmusesadiscretizationoftheworkpartboundary,similartothemeshesusedinFEA.However,unlikeFEA,ourattentionisonthemeshnodes,ratherthanonthemeshelements.Discretizationwaschosenforthefollowingreasons:First,wecanhandleworkpartswitharbitrarygeometry,aslongasthepart’sboundaryisacollectionofsmoothsurfaceswhichweknowhowtomesh.ThisrequirementissatisfiedbyallsurfacesusedinmodernCADsystems.Second,discretizationisnecessaryinordertoavoidanexpensivecomputationofgeodesiccurves.Third,discretizationshouldnotsignificantlyaffecttheresults,aslongasthenumberofdiscretecandidatelocationsontheboundaryismuchlargerthanthenumberofsurfaces.Inourimplementationthediscretizedboundaryconsistsofseveralhundredpointsonly.Experimentalevidenceindicatesthatthisissufficientforrealisticworkparts.Weintroduceapotentialfieldontheworkpartboundarydefinedbyzonesofattractionandrepulsion,whichwecallP-zones.Thecontactsaremodeledaschargedparticlesthatmoveontheboundarydrivenbythispotentialfield.Thecontactsarealsosubjecttomutualrepulsionbasedonthedistancebetweeneachtwocontactsinthewrenchvectorspace.Thealgorithmexecutesaseriesofsimulationepochs.Eachepochstartswitharandomconfiguration,proceedsthroughacertainnumberofstepstowardlowerpotentialenergyandendswithatestforkinematicconditions(formclosure).Thealgorithmterminateswhenanepochproducessatisfactoryconfiguration.Tospreadthecontactpointsontheboundarywesimulaterepulsionbetweeneachpairofthem.Theintensityofrepulsionbetweentwocontactpointsdependsonthedistancebetweentheircorrespondingwrenchesinthewrenchvectorspace.Oursimulationproceedsinalimitednumberofstepsoruntilequilibriumisreached.Theresultingplacementshouldhaveagoodchanceofleadingtoagoodfixture.Sucharandomizedmethodassumesthatthesetofn-tuplesofcontactpoints(forngreaterthanthree)thatsatisfythekinematicrequirementshasmeasuregreaterthanzeroandisrelativelylarge.Thatis,thesolutionspaceislarge.Althoughwehavenotbeenabletoprovethishypothesismathematically,ourexperimentshaveconfirmedit.Moreover,themeasureincreaseswiththenumberofcontactpoints,e.g.itiseasiertofindaformclosurearrangementwitheightpointsthanwithseven.Thenotionofrepulsionisessentialinourmethodasitallowsotherconsiderationstobeaccommodatedeasily.Wecanputadditionalrepulsionspotsontheworkpartboundarytorepresentforbiddenregions.Wecanalsointroducecentersofattraction.Thesecorrespondtoareasthatwererecommendedbytheanalysisphaseasdesirableforplacingcontactpoints,e.g.datumsurfaces.Thus,weproposeapotentialfieldforuniformlyrepresentingheterogeneousfixturinginformation.Regionsofrepulsioncorrespondtoareaswithpositivepotential.Negativepotentialisassociatedwithattraction.Zeropotentialcorrespondstoneutralareas.Theinitialrandomlyselectedcontactpointsareregardedasparticlesthatarebeingattractedorrepelledbyapotentialfieldthatincludesapairwiserepulsion.Thegoalofthesystemofcontactpointsistominimizeitstotalpotentialenergy.2TheInputTheinputtoouralgorithmconsistsofCADmodelsoftheworkpartboundaryandasetofsolidP-zones.EachP-zonedefinesapotential-fieldinfluencingregionwithnon-zerocharge.3DiscretizingtheWorkpartBoundaryThefirststepinourmethodistodiscretizetheboundaryoftheworkpart,thuscreatingthecandidatecontactpointlocationswhichwecallnodes.Discretizationisdonebyinvokingastandardfaceterembeddedinthegeometricmodelerweuse.Thediscretizationisstoredinanorientedgraphdatastructure.Eachnodeofthegraphcorrespondstoanodeonthemesh.Theedgesofthegraphcorrespondtoedgesofthemeshconnectingneighboringnodes.Ateachnodethescrewrepresentingthepointcontactiscomputedandstored.Ascrewisaconciseandconvenientrepresentationofthesurfacenormalandthelocationofthenode.Itisusedinallkinematictestsbasedonscrewtheory.4ComputingthePotentialFieldThecontactpointsinouralgorithmaresubjecttothecombinedactionoftwocomponentsformingthepotentialfield.Thebackgroundpotentialfieldisoneofthesecomponents.ItisgeneratedbytheP-zonesanddoesnotdependonthelocationofthecontactpoints.Thebackgroundpotentialfieldiscomputedonlyonce,inthebeginningofthealgorithm.Theothercomponentisdynamicandisduetotherepulsionbetweenthecontacts.Thedynamiccomponentiscomputedateachepoch.Thecomputationofthebackgroundpotentialfieldproceedsasfollows:First,wefindallnodesthatlieinsideP-zones.WeperformmembershipclassificationofeachnodeagainsteachP-zone[Tilove1980].IfthenodeisinsideacertainP-zone,thechargeoftheP-zonecontributestothenode’scharge.Thecontributionmaybepositiveornegative,dependingonthesignofthezone’scharge.AfterthisprocedurethenodesthatclassifyoutsideallP-zonesremainwithzerocharge.IfanodemclassifiesinsideP-zonesz1,z2...zkitschargeCmequalsthesumofthechargesofthoseP-zones:AfterthechargeofthenodesinsideP-zonesisevaluatedweproceedbycomputingthepotentialofallnodes.WedefinethepotentialatachargednodetobeinitiallyequaltoitschargePm=Cm.ForeachchargednodemwithchargeCmweperformabreadth-firsttraversalofitsneighborsupdatingtheirpotentialaccordingtotheformula：Hered(m,n)isthedistancebetweennodesm(thechargednode)andn,andd0isaconstantcalleddistanceofinfluence.Thedistancebetweentwonodesisdefinedasthenumberofedgesontheshortestpathbetweenthemonthemeshboundaryapproximation(REF_Ref347639717Figure3).FigureSEQFigure\*ARABIC3:DistancebetweentwonodesonthemeshAssumingthemeshsatisfiescertaincommonqualityrequirements,thisdistanceapproximatesquitewelltheactualgeodesicdistancebetweentwopointsontheobject’sboundary.Thebreadth-firsttraversalgoesonlyd0nodesdeep.Thusachargednodecausesupdatesofthepotentialonlyinitsd0-neighborhood.Forexample,ifthethreedarknodesinREF_Ref347639655Figure4havecharge100andd0=3thepotentialinthispartofthemeshwillbeasshownbythenumbersnexttoeachnode.FigureSEQFigure\*ARABIC4:PotentialfieldgeneratedbythreechargednodesThedynamicpotentialrepresentsrepulsionbetweenthecontactpoints.Therepulsionbetweentwocontactsdependsonhowdistanttheircorrespondingscrewsareas6-dimensionalvectors:Hereisasmallnumbertoavoiddivisionbyzero,isascalingfactorthatmakesthedynamicpotentialcompatiblewiththebackgroundcomponent,and(m,n)istheEuclideandistancebetweenthescrewsatnodesmandn.Therationalebehindrepulsionbasedonscrew-distanceisthefollowing:AnecessaryandsufficientconditionforformclosureisthatthesetofcontactscrewspositivelyspanstheentireR6[Wagneretal.1995].Asthecontactscrewsrepeleachother,theywilltendtodistributeregularlyinthespace,thusincreasingthepossibilityofformclosure.5EpochsEachepochstartswitharandominitialplacementofcontactpoints.Thenthesecontactpointsaresubjectedtothecombinedforcesduetothebackgroundpotentialfieldandtherepulsionbetweenthecontactpointsthemselves.Thealgorithmproceedsinaniterativefashion.First,thedynamiccomponentoftheaggregatedpotentialfieldiscomputedaccordinglyto(3).Thedynamicpotentialiscomputedonlyatthecontactsandtheirimmediateneighbors.Afterthecombinedpotentialiscomputed,eachcontactismovedtotheneighbornodewiththelowestpotential.Thusastepiscompleted.Ifthenumberofstepshasreachedacertainlimit,ornocontactwasmoved(i.e.equilibriumhasbeenreached),theepochiscompleted.Throughoutthisprocessspecialattentionispaidtonodesthatlieonedgesandverticesoftheworkpart.Thesenodesdonothaveascrewassociatedwiththemasthereisnonormaldefinedthere.Therefore,theycannotbeapossiblecontactlocation.Instead,theyservemerelyastransitnodesinthesimulation.Thisisachievedbyalwaysconsideringtheneighborsofsuchanodewheneverthenodeitselfisaddressed.Thenetresultofanepochisthattheinitiallyrandomconfigurationtransformsintoonethathasmoreregulardistributionofcontactscrewsinthescrewvectorspace,whileatthesametimekeepingawayfromrepulsionzonesandprovidingcontactsinsideattractionzones.6TestInthetestphasewecheckwhethertheplacementofcontactpointsprovidesformclosure.ThisisdoneusingthemethodofChouetal.[Chouetal.19??]Ittestswhetherthereexistsanon-zeromotionscrewthatcomplieswiththeconstraintsimposedbythecontactwrenches:Theexistenceofsistestedusinglinearprogrammingtechniques.Ifnosuchmotionexiststhearrangementofcontactsprovidesformclosure.Ifthetestsucceedsthealgorithmterminates.Otherwiseanewepochisinitiated.IfthetestfailsandacertainnumberofgenerationshavebeentriedweincreasethenumberofcontactpointsC.IncreasingCimprovestheprobabilityofendingupwithaformclosureconfigurationaswellashavingmorecontactsinP-zonesofattraction.Thealgorithmensuresthatnotwocontactpointsareplacedonthesamemeshnode.Therefore,intheextremecasetherearethreecontactsoneachface.Suchaplacementobviouslyimmobilizesanypolyhedralpart.Hencethecompletenessofthealgorithm(atleastforpolyhedralparts).Afteraredundantform-closureconfigurationiscomputed,thealgorithmcanremovetheextracontactsintheorderofdecreasingbackgroundpotential,i.e.startingwiththeonesinP-zonesofhighestrepulsion.Redundantfixturesaresometimespreferred,astheyminimizepartdeflectionandvibration.Thesystemcanoperatewithorwithoutredundancyreduction.Thedecisionmightbeguidedbytheanalysisphasebasedonthegeometricshapeofthepartandthemagnitudeoftheexternalforces,orahumanoperatormayallowredundancymanuallyandevenforceitbysettingtheinitialnumberofcontactstobemorethanthetheoreticalminimum(7in3D).Itispossibleforthekinematictesttosucceed,butthepotentialatsomecontactstobehigh.Thiscanhappenifacontactistrappedinalocalminimumofthepotentialfieldwherethepotentialishigh.Tohandlesuchsituationsweintroduceathresholdparametercalledmaximumallowablepotential.Arrangementswithpotentialatanycontacthigherthanthethresholdarediscarded.Thisnewtestmayleadtosituationsinwhichthealgorithmdoesnotterminatebecausenofixtureexistswithsufficientlysmallpotential.(Imaginetheextremeexamplethattheentireworkpartboundaryisaforbiddenregion.)Therefore,welimitthenumberofepochstoensuretermination.Inthecaseofsuchterminationthealgorithmoutputsthesolutionwiththelowestmaximumpotential.7.DiscussionTheproposedalgorithmsolvestheessentialprobleminfixturedesign–placingcontactpointsontheworkpartthatprovideformclosure.Itcanbeincorporatedinacompletefixturedesignsystemthatprovidesmodulesforfixturingtaskanalysisandlayoutdesign.Thealgorithmprovidesasimple,butpowerfulinterfacetothefixturingtaskanalysismodulesbasedonzonesofattractionandrepulsion.Admittedly,noteverycontactconfigurationcanbeimplementedbyacertainfixturingtoolkitinthelayoutdesignphase.Itmaybenecessarytoinvokethecontactplacementalgorithmseveraltimesuntilafeasibleconfigurationisproduced.7.1FixturingTaskAnalysisVariousfixturingheuristicsandrequirementscanbeexpressedintermsofzonesofhigherattractionorrepulsion.Forexample,attractionzonesmaybeusedtorepresent:datumsurfacesmachinedsurfacessurfaceswith“good”orientationareaswithgoodaccessibilityareasthatneedadditionalsupporttopreventdeflectionanddeformationRepulsionzonescanrepresent:inaccessibleareasforbiddenareasduetotoolaccessibilityrequirementssurfaceswithpoororientationcastsurfacessensitivesurfacesthatarevulnerabletoscratchingetc.AnimportantopenproblemishowtoassignnumericalvaluestotheP-zonepotential.Onepossibilityistoclassifytheconstraintsintoasmallnumberofcategories,e.g.“strongrepulsion”,“repulsion”,“neutral”,“attraction”,“strongattraction”.Allconstraintswithinthesamecategoryareassignedthesamepotential.Whilesuchaschemedoesnotreflectsubtledifferencesinprioritiesofthefixturingconstraints,itwillprobablycapturethemostimportantones.7.2FixtureCompletionAnimportantpropertyofthealgorithmisthatitallowspartialfixturestobeinput.Partialfixturesmaybeproducedbyotherfixturingagents,humansorcomputerprograms,whoplacecertainfixelstheyknowarenecessaryandhandtheworkovertoouralgorithmforcompletion.Thealgorithmthenplacesadditionalcontactssothatformclosureisachieved.Werepresentthepartialfixtureasfixedcontactswhichparticipateinthemutualrepulsionwiththefreecontacts,butarenotallowedtomove.Inthislight,thealgorithmmaybeviewedasafixturecompletionengine7.3Non-determinismandRedundancy.Duetotherandomnessoftheinitialplacementineachgeneration,thealgorithmisnon-deterministic,i.e.itcanproducedifferentsolutionsgiventhesameinput.Thisisdesirableasacontactpointconfigurationmayberejectedbythelayoutdesignmoduleandthealgorithmwillhavetoproduceanothersolution.Thealgorithmmayproduceredundantfixturesincertaincases.Redundantfixtureshavedrawbacksaswellasadvantagesovertheminimalones.Certainly,theyimpairloadabilityandwastecomponents.However,theymayalsominimizepartdeflectionanddeformation.Inpractice,humandesignersoftenproduceredundantfixtures.7.4EfficiencyTherunningtimeofthealgorithmdoesnotdependdirectlyonthecomplexityoftheworkpartboundary.Asimplecuboidandacomplexcurvedworkpartwillbediscretizedwithacomparablenumberofmeshnodes.Thisdecisionisbasedontheintuitiveassumptionthatafewhundredevenlydistributednodesontheboundaryprovideasufficientbasisforfixturabilityofanysolidobject.自動夾具在三維中的合成摘要夾具是一個安排在裝夾模塊中的位置，并進行工件在一個以制造業(yè)為主的運作。我們在這項工作中,考慮固定裝置與無摩擦點接觸，并給出了一個方案，為安置的接觸點上的非棱柱體三維工件。它是一個非確定性，勢場算法的接觸點安置。該方法提供了一個基本框架，為整合異構高層次裝夾代理商通過一個界面基于區(qū)的吸引力和斥力就工件邊界。該算法可能會產生多余的固定裝置，并能增加部分的解決辦法，以形成完整的封閉裝置。導言夾具是一個安排的裝夾模塊中的位置，并舉行工件在一個以制造業(yè)為主的操作，如加工，裝配和檢驗。裝夾是最重要的，以工業(yè)制造，并構成的一個重要部分，所有的制造成本。因此，夾具設計自動化是非常重要的。夾具設計涉及多種因素，例如，克制，決定性的位置，裝載和工具無障礙環(huán)境。高效的算法處理整個一系列的裝夾問題，為全面域工件尚不存在。最近，brost和彼得斯出版了一種算法[brost＆彼得斯1996]延伸早前經典的工作brost和戈德堡[brost＆戈德堡，1994]，以三維域。這種算法，但需要縱向和橫向平面構成相當大一部分的工件邊界。它產生的所有可能的固定裝置，然后在利率，他們因此對某些衡量標準。這是在計算上昂貴的。Wagner等提出了一種算法，使用7個模塊的Struts安裝在一個盒子里，以夾具多面體[Wagner等，1995年]。這個算法是不全面的，在這個意義上講，它并不能有效地處理某些情況下，例如一個立方體的臉平行包裝盒。它也經歷著從高計算復雜度。wallack和精明提出另一種方法，并有"列舉與匯率"的味道[wallack＆Canny，1996年]。它可以夾具棱柱工件與平面和圓柱垂直表面。龐塞提出了一種算法，利用曲率的影響，計算出固定裝置與四指為多面體零件[龐塞96]。在數(shù)量減少的接觸應提供更好的復雜算法，但質量的生產設備，似乎不亞于那些利用更多的接觸，并提供古典形式封閉。在這篇文章中我們提出了一種新的潛在場算法，有效地生產優(yōu)質夾具設計。我們的算法工程任意工件，并提供便捷的普遍手段，代表不同的裝夾要求。這種算法是一種直接泛化的二維勢場裝夾算法penev和requicha[penev＆requicha1996]。我們認為，固定裝置與無摩擦點接觸。它已證明七名接觸是必要的。[somoff，1900]，并有足夠的[markenscoff等人，1990年]固定任何工件在三維繼至少承諾的策略，過程夾具合成可分為三個階段-裝夾任務分析，接觸點安置以及夾具布局設計。在裝夾任務分析階段工件幾何和制造過程中分析，以確定各種參數(shù)的裝夾問題，如切削力，交通不便或禁止的領域，并找出特點，可用于申請裝夾裝置，例如機械平面，橫向和縱向表面，對平行表面，對垂直于表面，等等。圖1：接觸點安置在接觸點安置階段的一些聯(lián)絡點，是擺在工件邊界（圖1），因此由此產生的配置接觸滿足確定的限制因素，在分析階段，以及一些運動學要求必須得到滿足，任何夾具如完全克制。圖2：從接觸點配置，以夾具布局設計

在布局設計階段"水塔"的裝夾元件是建立并置于周圍工件等，以接觸的部分，在點位置計算，在接觸點安置階段。舉例來說，一個接觸點上，橫向工件表面（圖甲），可導致以實例化的額外開銷鉗說，接觸了工件在那個特定點（圖2B）條。這是一個以設計為功能的問題，制約了一套可裝夾單元及其參數(shù)。這實現(xiàn)了套聯(lián)絡點的功能規(guī)格及夾具布局是一個配置的部件。在本研究中，我們的重點聯(lián)系點安置，并把它納入其中部分和任務的分析。安排的接觸點必須滿足某些運動學條件，以一個基礎，有一個良好的夾具。特別是，它必須提供的封閉形式，確定位置，夾緊穩(wěn)定，脫離能力和裝載[Asada&By]。該算法采用離散化的工件邊界，類似的網(wǎng)格所使用的有限元分析。但是，不同于有限元分析，我們注意的是，對網(wǎng)格節(jié)點上，而不是放在網(wǎng)格元素。離散選擇為以下幾個原因：首先，我們可以處理工件任意幾何，只要把部分的邊界是一家集表面光滑，而我們知道如何主題詞。這項規(guī)定是滿意的所有表面用在現(xiàn)代CAD系統(tǒng)。其次，離散化是必要的，以避免昂貴的計算測曲線。第三，離散應該不會大大影響結果，只要有多少離散候選地點就邊界要遠遠大于人數(shù)表面上。在我國實施離散邊界構成的幾百點。實驗證據(jù)表明，這是不夠現(xiàn)實的工件。我們引進一個潛在場對工件邊界界定區(qū)的吸引與排斥，我們稱之為個P-區(qū)。接觸是仿照由于帶電粒子的這一舉動對邊界驅動這個潛在的領域。接觸也受到相互排斥的基礎上，之間的距離每兩個接觸，在扳手向量空間。該算法執(zhí)行了一系列的模擬時代。每一個劃時代的開始，以隨機配置，收益是通過一定數(shù)量的步驟，向低勢能和結束一場考驗運動學條件（形成封閉）。該算法終止時，一個劃時代的產生令人滿意的配置。傳播接觸點上的邊界，我們模擬斥力之間相互對他們。強度斥力之間的兩個接觸點，取決于它們之間的距離及其相應的扳手在扳手向量空間。我們的模擬收益，在有限的幾個步驟，或直至平衡是達成共識。由此產生的就業(yè)，應該有很好的機會，導致一個好的夾具。這種隨機方法假定一套正元組的聯(lián)系點（對N大于3）表示，滿足運動學要求，有措施，都大于零，是比較大。這就是說，解空間非常大。雖然我們尚未能證明這一假設的數(shù)學，我們的實驗已經證實了它。此外，這項措施增加多少接觸點，例如，這是比較容易找到一個封閉的形式安排多于8分之7。概念斥力是必不可少的方法，因為這可以容易容納其他因素。我們可以把更多的斥力點就工件邊界，以代表故宮地區(qū)。我們還可以介紹中心的吸引力。這些對應的地方被推薦人的分析階段可取配售聯(lián)系點，例如，基準面表面。因此，我們提出一個勢場為代表一致異構裝夾信息。地區(qū)斥力對應地區(qū)的積極潛力。負電位，是與魅力。零電位對應于中立地區(qū)。初始隨機抽選的聯(lián)系點，被視為微粒，正在吸引或擊退一個勢場，其中包括成對斥力。目標體系的聯(lián)系點是為了最大限度地減少其總勢能。輸入輸入我們的算法包括CAD模型的工件邊界，以及一套堅實的P-區(qū)。每個人P-區(qū)界定一個潛在場的影響區(qū)域與非零收費。三離散工件邊界，第一步，我們的做法是把離散邊界的工件，因而創(chuàng)造候選人接觸點的位置，我們稱之為節(jié)點。離散化是做了引用標準工作面嵌入在幾何造型。離散是儲存在一個面向圖形數(shù)據(jù)結構。每個節(jié)點的圖形對應的一個節(jié)點上的網(wǎng)格。邊緣的圖形對應邊的網(wǎng)格連接相鄰節(jié)點。在每個節(jié)點螺絲代表聯(lián)系點，是計算和儲存。螺絲釘是一個簡潔和方便的代表性表面正常位置的節(jié)點。它是用來在所有運動測試基于螺旋理論。離散工件邊界第一步，我們的做法是把離散邊界的工件，因而創(chuàng)造候選人接觸點的位置，我們稱之為節(jié)點。離散化，是做了，引用標準表面嵌入在幾何造型，我們使用。離散是儲存在一個面向圖形數(shù)據(jù)結構。每個節(jié)點的圖形對應的一個節(jié)點上的網(wǎng)格。邊緣的圖形對應邊的網(wǎng)格連接相鄰節(jié)點。在每個節(jié)點螺絲代表聯(lián)系點，是計算和儲存。螺絲釘是一個簡潔和方便的代表性表面正常位置的節(jié)點。它是用來在所有運動測試基于螺旋理論。計算勢場聯(lián)系點，在我們的算法是受聯(lián)合行動，由兩部分組成，形成了潛在的領域。背景勢場是其中的組成部分。這是產生由P區(qū)和不依賴于地理位置的聯(lián)系點。背景勢場的計算方法是只計算一次，在一開始的算法。另一部分是動態(tài)的和，這是由于該斥力之間的接觸。動態(tài)部分是計算機在每一個劃時代的。計算的背景勢場的收益如下：首先，我們找到所有的節(jié)點所在內的P-區(qū)。我們履行會員分類每個節(jié)點對每個人P-區(qū)[tilove1980年]。如果節(jié)點內一定的P-區(qū)，負責為P區(qū)，有助于節(jié)點的電荷。貢獻，可以是正面的還是負面的，這取決于該標志區(qū)的電荷。經過這個程序的節(jié)點進行分類外，所有的P-區(qū)仍具有零收費。如果一個節(jié)點米制內的P-區(qū)Z1的，z2的...專用料ZK其負責厘米等于一筆收費的那些人P-區(qū)：之后，負責該節(jié)點內的P-特區(qū)，是我們評價我們開始通過計算潛在的所有節(jié)點。我們界定的潛在處于被控節(jié)點，初步等于它的電荷時=厘米。每個被控節(jié)點m的范圍內負責厘米，我們演出廣度優(yōu)