机械毕业设计英文外文翻译493五轴数控铣床翻译

英文翻译1【附】英文原文翻译文献：Five-axismillingmachinetoolkinematicchaindesignandanalysis作者：E.L.J.Bohez文献出处：InternationalJournalofMachineTools&Manufacture42(2002)505–520翻译页数：Five-axismillingmachinetoolkinematicchaindesignandanalysis1.IntroductionThemaindesignspecificationsofamachinetoolcanbededucedfromthefollowingprinciples:●Thekinematicsshouldprovidesufficientflexibilityinorientationandpositionoftoolandpart.●Orientationandpositioningwiththehighestpossiblespeed.●Orientationandpositioningwiththehighestpossibleaccuracy.●Fastchangeoftoolandworkpiece.●Savefortheenvironment.●Highestpossiblematerialremovalrate.Thenumberofaxesofamachinetoolnormallyreferstothenumberofdegreesoffreedomorthenumberofindependentcontrollablemotionsonthemachineslides.TheISOaxesnomenclaturerecommendstheuseofaright-handedcoordinatesystem,withthetoolaxiscorrespondingtotheZ-axis.Athree-axismillingmachinehasthreelinearslidesX,YandZwhichcanbepositionedeverywherewithinthetravellimitofeachslide.Thetoolaxisdirectionstaysfixedduringmachining.Thislimitstheflexibilityofthetoolorientationrelativetotheworkpieceandresultsinanumberofdifferentsetups.Toincreasetheflexibilityinpossibletoolworkpieceorientations,withoutneedofre-setup,moredegreesoffreedommustbeadded.Foraconventionalthreelinearaxesmachinethiscanbeachievedbyprovidingrotationalslides.Fig.1givesanexampleofafive-axismillingmachine.英文翻译22.KinematicchaindiagramToanalyzethemachineitisveryusefultomakeakinematicdiagramofthemachine.Fromthiskinematic(chain)diagramtwogroupsofaxescanimmediatelybedistinguished:theworkpiececarryingaxesandthetoolcarryingaxes.Fig.2givesthekinematicdiagramofthefive-axismachineinFig.1.Ascanbeseentheworkpieceiscarriedbyfouraxesandthetoolonlybyoneaxis.Thefive-axismachineissimilartotwocooperatingrobots,onerobotcarryingtheworkpieceandonerobotcarryingthetool.Fivedegreesoffreedomaretheminimumrequiredtoobtainmaximumflexibilityintoolworkpieceorientation,thismeansthatthetoolandworkpiececanbeorientedrelativetoeachotherunderanyangle.Theminimumrequirednumberofaxescanalsobeunderstoodfromarigidbodykinematicspointofview.Toorienttworigidbodiesinspacerelativetoeachother6degreesoffreedomareneededforeachbody(toolandworkpiece)or12degrees.Howeveranycommontranslationandrotationwhichdoesnotchangetherelativeorientationispermittedreducingthenumberofdegreesby6.Thedistancebetweenthebodiesisprescribedbythetoolpathandallowseliminationofanadditionaldegreeoffreedom,resultinginaminimumrequirementof5degrees.英文翻译33.LiteraturereviewOneoftheearliest(1970)andstillveryusefulintroductionstofive-axismillingwasgivenbyBaughman[1]clearlystatingtheapplications.TheAPTlanguagewasthentheonlytooltoprogramfive-axiscontouringapplications.TheproblemsinpostprocessingwerealsoclearlystatedbySim[2]inthoseearlierdaysofnumericalcontrolandmostissuesarestillvalid.BoydinRef.[3]wasalsooneoftheearlyintroductions.Beziers’book[4]isalsostillaveryusefulintroduction.Held[5]givesaverybriefbutenlighteningdefinitionofmulti-axismachininginhisbookonpocketmilling.Arecentpaperapplicabletotheproblemoffive-axismachineworkspacecomputationisthemultiplesweepingusingtheDenawit-HartenbergrepresentationmethoddevelopedbyAbdel-MalekandOthman[6].Manytypesanddesignconceptsofmachinetoolswhichcanbeappliedtofive-axismachinesarediscussedinRef.[7]butnotspecificallyforthefive-axismachine.henumberofsetupsandtheoptimalorientationofthepartonthemachinetableisdiscussedinRef.[8].AreviewaboutthestateoftheartandnewrequirementsfortoolpathgenerationisgivenbyB.K.Choietal.[9].GraphicsimulationoftheinteractionofthetoolandworkpieceisalsoaveryactiveareaofresearchandagoodintroductioncanbefoundinRef.[10].英文翻译44.Classificationoffive-axismachines’kinematicstructureStartingfromRotary(R)andTranslatory(T)axesfourmaingroupscanbedistinguished:(i)threeTaxesandtwoRaxes;(ii)twoTaxesandthreeRaxes;(iii)oneTaxisandfourRaxesand(iv)fiveRaxes.Nearlyallexistingfive-axismachinetoolsareingroup(i).Alsoanumberofweldingrobots,filamentwindingmachinesandlasermachiningcentersfallinthisgroup.Onlylimitedinstancesoffive-axismachinetoolsingroup(ii)existforthemachiningofshippropellers.Groups(iii)and(iv)areusedinthedesignofrobotsusuallywithmoredegreesoffreedomadded.Thefiveaxescanbedistributedbetweentheworkpieceortoolinseveralcombinations.Afirstclassificationcanbemadebasedonthenumberofworkpieceandtoolcarryingaxesandthesequenceofeachaxisinthekinematicchain.Anotherclassificationcanbebasedonwheretherotaryaxesarelocated,ontheworkpiecesideortoolside.ThefivedegreesoffreedominaCartesiancoordinatesbasedmachineare:threetranslatorymovementsX,Y,Z(ingeneralrepresentedasTTT)andtworotationalmovementsAB,ACorBC(ingeneralrepresentedasRR).Combinationsofthreerotaryaxes(RRR)andtwolinearaxes(TT)arerare.Ifanaxisisbearingtheworkpieceitisthehabitofnotingitwithanadditionalaccent.Thefive-axismachineinFig.1canbecharacterizedbyXYABZ.TheXYABaxescarrytheworkpieceandtheZ-axiscarriesthetool.Fig.3showsamachineofthetypeXYZAB
,thethreelinearaxescarrythetoolandthetworotaryaxescarrytheworkpiece.英文翻译55.Workspaceofafive-axismachineBeforedefiningtheworkspaceofthefive-axi