雙層柔性鉸鏈微小夾持器英文版

TheDesignofTwoJayerFlexibleHingeMilli-gripperHuibaoChenPingSunDeptofPrecisionMech.Eng.ShanghaiUnivei'sityJiading.shanghai201800,P.R.CAbstractThepaperintroducesthedesign,manufactureandexperimentofthetwo-layerflexiblelungemilli-gripperindetails.Afterthestmetureandthecharactersofpiezoelectricelementandtwo-layerflexiblehingeareanalyzed,theamplificationofdisplacementiscalculated.Thegripperhashighsensitivity,simplestructure,awiderangofusageandagreatfuturesuchasmilli-robotformedicaltreatment,inspectingandminitubeaswellasmilitaryusage.Itisanewtypeofmillimachine.1.INTRODUCTIONEversincemici'o-clectyonicteclinologyfounditsvzayinvanousfieldsofmechanicalenguiecnng.Mechafa'onichasbecometliemostnnpoitantfeatureofmodemmechanicalscienceandteclinology.This,atthesametime,greatlystnnulatedtlieprecisionmachinetodeveloptowardsmici'oandnitelligent.Iinitiatedberweenmidandlate80's,tliestudyofmicromachnieintensivelyhasreflected.MicromachinecanbedividedintomicromachineandmillimachineMillnnachinevzhichhasthecharacterofmillimetersizeandmicromachinevzhichhasthecharacterofmicronsizehavebecomethefocusofup-to-dateresearchinmteinationalscienceandtechnologysocietyThesatusinmedicaltreatment,mecro?electronicprecisionmantfacture,microassemblyandacmauticcannotbereplacedbyotliersizelimitedmachines,henceitreasonablyfastisdeveloped.Milli-gnppei'isaveiynnpoitantpartbothintliedevelopmentofmicro-robotandinthepracticeofmillimachine.Therefore,weisnovzheadingforthestudyandthedevelopmentofmollogripper.Themilli-gnppei'ismadeupoftwopartsdnvingpartandoperatingpartTherearetwolindsofcommondrivingparts.OneiscalledPZT(piezoelectric)actuator,vzhichhasthecharactersofsunplepinciple,steadyactionandhighresponseInpresent,tlierearemanytypesofOperatingmechanism,butmainlytlierearethreefomisinourresearchandusegearandrackmechanism,obliquevzedgemechanismandflexiblehingemechansmTheflexiblehingemechanismwhichcanamplifythemici'odisplacementintnnesisbettertliantheothertwoUtilizingtinsadvantage,itismadeupthemilli-gtippei'usingPZTactuatorwithPZTelementtogetlierFiguregivesamodelwemadeFigurelaisasinglestageflexiblehingegripperandfigurelbistwo-stageflexiblehingegripper.卜singleKtruclure卜singleKtruclureb?(uo-jeta□nictuneFig1:Flexiblelungemilli-grippersHowever,thedefonnationofthePZTclementisquitelimited(about6.5/mi/lOOv[Althoughwehavesucceededinamplify!ngtomechanism:theoutputofgreppersisstillnotlarge.(normallyabout90/mi/10(X^)」ftheamplificationofmechanismisincreased,thegripper*ssizewillbebiggerandit'stsingfieldwillbelimited.Inorsertoincreasetheamplificationandnottoenlargethegripperssize.anothertypeogmilli-gripperisdesigned」tistheweo-layerflexiblehingemilligripperusingPZTactuator.2.STRUCTUREANDACTIONPRINCIPLEThetvzo-layerflexilehingemilligi'ipperisanintegratedmodulewhichtuenselectricpowerintomechanicpowertorealizethegnppingfunction.ItsdrivingsourceistliePZTelementwhichisembeddedintliecentei'ofthefirstlayerflexiblehinge,WlientherelevantvoltageappliedtotliePZTelement,thePZTelementproductsdefonnation,tlierebymakingthefirstlayerflexiblehingerealizethefirststageamplificationofdisplacementandthen,itwillmakethesecondlayei'realizethesecondstageamplification,atthesametime,realizethegnppingfunction,figure2sitliesimplegraphoftliegnppei'Fig.2:Two-layerflexiblehingemilli-gnpperTheactuatoristhestackedPZTelement,whichismadeupofmanylayersofPZTelementlamellae(figure3showsthis)Thei'eareelecti'odesalongtliepolarizationdirectionofthebothsodesoftheelement,thepolarizationdirectionofadjacentlamellaeisoppositedirectionsofelechicfield.sotheyhacetliesamedirectionsofdisplacement.WhenmanyPZTelementlamellaeareconnectedeceiyoneisunderthesamevoltage,andtliewholedisplaecmentisthesumofallthelamellae'sdiplacement.Fig.3ThestmcturegraphofstackedPZTelementThehingeofflexiblehingemechanismisatypeofelasticdeformationatoundaxis,v/hichisrecei'sibleTherearetwokindsofhinges,tliesingleaxisandthedoubleaxis,andv/echoosetliesingleaxisone.(figure4)Fig.4:HingedunensionsandvariousforcesandmomentswhichcausedeflectionsIndesignnig,theinputandoutputaxismustbennnble,andhingesshouldhaverigidityenough.Inpractice,tliegnppingendsofthegrippershouldhavegreateroutput,soweusethetvzosingle-stageflexiblehingemechanisms,aseachonecanamplifyonestage,Thetwomechanismsareconnectedtogetherwithhinge,inthisway,tlieyformtheoperatingpartofthetwoJayerflexiblehingemilli-gi'ippei'ThisdesigncannotonlydecreasetliestructuresizeofgripperinXandYdirectionsbutcanalsoincreasetlieamplificationofthedisplacement.Inworkingcondition,tlierearerelativerotationattheconnectionofthelointtodsSo,tlieconnectionstyleshouldkeeptherelativepositionbetvzeentlietwojointeods,andbeabletorotatefreelyatthesametime.Anditalsoshouldpreventtheclearancefitbetweentlieshaftandtheholefbomlosingtoomuchdisplacement,soweusetherotationfitwithsmallclearanceec.o.5H8/f7.3?CALCULATINGANDANALYZINGOFTHEGRIPPERSSTRUCTURETheoperatingmechanismoftwo-layerflexiblehingemille-gripperismadeupoftwoparts,andalsomadeupoftvzoparts,figure5showstlieloadnigconditionofthetvzosingle-stageflexiblehingemechanism

Fig5TheloadingconditionofflexiblehingesFigure5aisthefirstlayersingle-gradeflexiblehingemechanism,andstmctureissymmetric.TomakebriefmerelyonesideoftheoutputiscalculatedThesimpleloadinggraphisshownasfigure6.Accordingtothetheoryoftheequilibriumofstaticforceandmomentthefollowingequationsiscalculated:lblbFig6:Thesimpledrawingofstructure口AL.A.nAz-AX]-AXrFx」一FlhFx=M?kci=Ax2.kc3,0= ——-=-——-—⑴1 心+心IfA=殺]+雄円=心+心Thentherewillbe△zl—A?F-L8=—5 1+A?Becausey=lb?&Then1?+AThen1?+A?k&12+Ak,Furthermore,ifagivenobjectisgripped,thefollowingrelationswillexist.Ay=B?Az-C(4)Where1 +A-Kq13Where1 +A-Kq13+Ak,WhenBisaconstant,expresstheamplificationoftheaboveflexiblelunge,CisfunctionofFy,butifgripsagivenobject,FywillbeaconstantandCwillbeaconstanttoo.AzissubjecttothestnictureofthestackedPZTelement.AforceFzonlychargesonthestackedPZTelementinZ&rectionwhenworking,thesimplegraphofforceisshownasfigure7.Fig7TheloadingconditionofthesrackedPZTelementThethicknessofalamellaofthePZTelementist,andthedisplacementoftheelementlamellaisAt.AtcanbecalculatedwithfollowingequationAt=(f^?E?t+ ?Ez?t (5)島,d33aretliepei'fonnanceparameteroftliePZTelementelasticconstant,2.52x10"elasticconstant,2.52x10"11d33 piczoclecti'icconstant,9.95xl0-1IfthesectionareaoftheelementisS,thechargingvoltageisV,tlienThetotaldisplacementifnlayersofPZTelementisAzAz=n?At=—為Fzn七+d33Vn (6)sAsthedisplacementofthePZTelementisdifferentfromeachother,theelasticcounterforcefromthelungeisdifferenteither,Aziscalculatedbyfollowingequations,andthesimplegraphoflondingconditionisshownasfigure6.(replacingFzbyFA)Az=2<A^+d33.v.n,Forthisreason

Az=d33V-n?此iAz=d33V-n?此i】tk&(1?+A?k』?S(12+A?k』?s+城?k&?n?t1IfD= . li為i】tk&(1，+Ak』SThentherewillbe

此片入ntl

(P+A?k&)?s+務(wù)監(jiān)?n?tAz=D??V?n-P(9)Fromtheaboveformula(9)weknowtliatthePZTelementthatdrivestheflexiblehingemechainsmcannotworkunderthemaximumdeformationbecauseofthecounterforces.SubstituteAzintoequation(4).Thefollowingequationcanbegot:△y=M?d33Vn-N(10)IntheaboveequationM=ED=—1~+A?k&1M=ED=—1~+A?k&爲(wèi)mtk。Q?+A?k』?sN=P?B+C二1% |A.%."N=P?B+C二1% |A.%."F+A?k°l2+4?k&(1，+A?k&)?s+醴?k&?ii?tWhenworking,theoutputAyisalinearfunctionoftheexertedvoltage.ThroughthevoltagechargedonthePZTelement,theoutputofthegripperiscontrolledandadjusted.Mistheamplificationofthemechainsmwithoutcharge/Theamplificationofthefirstlayeroftheflexiblehingecanbegot:(Fy=0,D=1)11b仁(ID1+A?k&Theloadingconditionofthesecondlayerofflexiblehingeisshownasfigure5b.Itisaamplifyingmechainsmthatmakesuseofthechangeofarms'length,solargeramplificatuioncanbegot,andtheamplificationcanbecalculatedasbelow:K3=^-(12)Inourdesign,thestrucluresizeoftheflexiblehingeisdecidedonthebasisoftensilerigidity.shearingrigidityandtorsionalrigidityenough,theparametertobedesignedispresentedinthetablebelowTable1HingeN210

RadiusR(mm)0.300.30Hingewidtht(mm)0300.30Linkwidthh(mm)1701.30Hingethicknessb(mm)2002.00Distancebetweenhinges1(mm)2352.35=14911%mY-P=-2tail'1=14911%mY-P=-2tail'1/ ' ' =+ Jl-(l+0-汙J20+0Y-P[ypJl-(l+0fInwhich^th0==2R2RE elasticmodulusY-PInwhichY-P0=-2tan'1 7i-(i+z?-z)2G shearingelasticmodulusTorsionalrigidity:k廠?！?484%^z1+0 3+20+0，7(1+0 3+20+0，7(20+內(nèi)6(1+0)_(20+儼於_?tan'10Jl—(1+0一汀'Thentheamplificationofthetwo-layerflexiblehingenulli-gripperis:1212+小I3=35.11Figure8showsthesizeofthestructureformainparts.Figure9showsthemodeloftwo-layerflexiblehingenulli-gripperwemade.Fig.8「ThestructuresizeofmainpartsFig9Two-layerflexiblehingemilli-grippermodelWhentheinputofdrivingelementisAz.theoutputofthegripper(Fy=0)iscalculatedasfollowingrelation2Ay=k-Az-2^(13)Inwhich themostfitclearance,0030mmWhen0.5So,theoutputofthegripperis2Ay=35.11Az-0.060(14)1.EXPERIMENTANDANALYZINGMaterialThegripperconsistoftwomechanisms,butthestnictureformsareallflexiblelungeObviously,

theflexiblehingetakeadvantageofthecharactersofoneself'elastic.So,whenselectingmaterial,the

elasticfunction,thesensitivenessaswellashighdiamagneticshouldbeprefered.SuchasQBc2,QS116.5—0.1asthematerialofflexiblehingeAssemblingWegetthestackedPZTelementfromTOKINcompany.Ithasthecharactersofsmallsize,highresponseandlowdrivingvoltage.TheparameterofNLA-2x3x9stackedPZTelementusedduringtheexperimentarelistedasthefollowingfrom:Table2Sizeaxbxc(mm)2x3x9MaximumvoltageV100Maximumloadkg/lOOV21±20%Deformation/Z1I1/10(V6.5±10%Stacks65Distancebetweenpoles/fill115InsulationresistanceMG500Capacitance11F197Themanufactureoftheflexiblehingeusetheelectricmachiningtechnology.Themachiningaccueacyofthetechnologycanbe/Zillgrade.Theneedofdesigncanbesatisfiedbasically.Assemblysequenceare:Twoflexiblelungemechanismsaredrilledholetogether ■一connectingtwpmechanisms■一assemblingthedrivingelement.Inwhich.assemblingPZTelementisextremelydifficult.AsaresultoftheoutputofPZTelementisverysmall/Allandtheoutputof(ZTelementcanbereducedinassemblingprocess.TheassemblingaccuracymustbehighForthisreason,wedesognedfollowingstructure:SizeofmountingPZTelementlengthsize1=ofPZTelementThroughgrindingthesize1ofthemechanism,wecanachieveamicrointerferencetolz,that'sthefitbetweengrippingmechanismandPZTelementissmallinterferencefit.4.1MeasuringADWY-2typevibratingdisplacementinstrumentwasusedtodetectedthedisplacementofthe{ZTelement.Measuringrangeis0.05?100/ZillThemeasuingvalueofthePZTelement:whenlOOvisappliedtheoutputofPZTelementis6.4“11

Hencethen，&omformula(14),themostoutputofthegrippercanbecalculated:『T=2Ay=35.11x0.0064-0.060=0.1647nniThemeasurementofactualoutputgoontheexperimentalfacilityinfigure10.andtheoutputofthegripperwedetectedisintable3.MeasuringnumberN1o345Outputofdisplacement2Ay0.1210.1190.1350.1240.130MeasuringnumberN678910Outputofdisplacement2Ay0.1180.1310.1220.1260.131Theactualoutputofthegrippercanbegotyieal=2Ay=0.125^nmOverallsizeoftwo-layerflexiblelungenulli-gnpperis15.2x9.8x3.Totalweightis3gAftertheexperimentresultbecomparedtotheorycalculatingvalue,wecangot:yreal<ytfeoiy,and&sparityis23.6%5.CONCLUSIONTwo-layerflexiblehingenulli-gripperisanewintegra