下载

5下载券

加入VIP
  • 专属下载特权
  • 现金文档折扣购买
  • VIP免费专区
  • 千万文档免费下载

上传资料

关闭

关闭

关闭

封号提示

内容

首页 伺服电机原理与应用

伺服电机原理与应用.pdf

伺服电机原理与应用

公共广播台
2009-08-29 0人阅读 举报 0 0 暂无简介

简介:本文档为《伺服电机原理与应用pdf》,可适用于工程科技领域

中国工控信息网wwwcom收录伺服电机原理和应用ServomotorsareavailableasACorDCmotorsEarlyservomotorsweregenerallyDCmotorsbecausetheonlytypeofcontrolforlargecurrentswasthroughSCRsformanyyearsAstransistorsbecamecapableofcontrollinglargercurrentsandswitchingthelargecurrentsathigherfrequencies,theACservomotorbecameusedmoreoftenEarlyservomotorswerespecificallydesignedforservoamplifiersTodayaclassofmotorsisdesignedforapplicationsthatmayuseaservoamplifieroravariablefrequencycontroller,whichmeansthatamotormaybeusedinaservosysteminoneapplication,andusedinavariablefrequencydriveinanotherapplicationSomecompaniesalsocallanyclosedloopsystemthatdoesnotuseasteppermotoraservosystem,soitispossibleforasimpleACinductionmotorthatisconnectedtoavelocitycontrollertobecalledaservomotorSomechangesthatmustbemadetoanymotorthatisdesignedasaservomotorincludestheabilitytooperateatarangeofspeedswithoutoverheating,theabilitytooperateatzerospeedandretainsufficienttorquetoholdaloadinposition,andtheabilitytooperateatverylowspeedsforlongperiodsoftimewithoutoverheatingOldertypemotorshavecoolingfansthatareconnecteddirectlytothemotorshaftWhenthemotorrunsatslowspeed,thefandoesnotmoveenoughairtocoolthemotorNewermotorshaveaseparatefanmountedsoitwillprovideoptimumcoolingairThisfanispoweredbyaconstantvoltagesourcesothatitwillturnatmaximumRPMatalltimesregardlessofthespeedoftheservomotorOneofthemostusabletypesofmotorsinservosystemsisthepermanentmagnet(PM)typemotorThevoltageforthefieldwindingofthepermanentmagnettypemotorcanbeACvoltageorDCvoltageThepermanentmagnettypemotorissimilartootherPMtypemotorspresentedpreviouslyFigureshowsacutawaypictureofaPMmotorandFigshowsacutawaydiagramofaPMmotorFromthepictureanddiagramyoucanseethehousing,rotorandstatoralllookverysimilartotheprevioustypePMmotorsThemajordifferencewiththistypeofmotoristhatitmayhavegearreductiontobeabletomovelargerloadsquicklyfromastandstillpositionThistypeofPMmotoralsohasanencoderorresolverbuiltintothemotorhousingThisensuresthatthedevicewillaccuratelyindicatethepositionorvelocityofthemotorshaft中国工控信息网wwwcom收录FIGURETypicalPMservomotorsFIGURECutawaypictureofapermanentmagnetservomotorBrushlessServomotorsThebrushlessservomotorisdesignedtooperatewithoutbrushesThismeansthatthecommutationthatthebrushesprovidedmustnowbeprovidedelectronicallyElectroniccommutationisprovidedbyswitchingtransistorsonandoffatappropriatetimesFigureshowsthreeexamplesofthevoltageandcurrentwaveformsthataresenttothebrushlessservomotorFigureshowsanexampleofthethreewindingsofthebrushlessservomotorThemainpointaboutthebrushlessservomotoristhatitcanbepoweredbyeitheracvoltageordcvoltageFigureshowsthreetypesofvoltagewaveformsthatcanbeusedtopowerthebrushlessservomotorFigurellashowsatrapezoidalEMF(voltage)inputandasquarewavecurrentinputFigurellbshowsasinusoidalwaveformfortheinputvoltageandasquarewavecurrentwaveformFigurellcshowsasinusoidalinputwaveformandasinusoidalcurrentwaveformThesinusoidalinputandsinusoidalcurrentwaveformarethemostpopularvoltagesuppliesforthebrushlessservomotorFigureshowsthreesetsoftransistorsthataresimilartothetransistorsintheoutputstageofthevariablefrequencydriveInFigllathetransistorsareconnectedtothethreewindingsofthemotorinasimilarmannerasinthevariablefrequencydriveInFiglbthediagramofthewaveformsfortheoutputofthetransistorsisshownasthreeseparatesinusoidalwavesThewaveformsforthecontrolcircuitforthebaseofeachtransistorareshowninFigllcFigurelldshowsthebackEMFforthedrivewaveforms中国工控信息网wwwcom收录FIGURE(a)Trapezoidalinputvoltageandsquarewavecurrentwaveforms(b)Sinusoidalinputvoltageandsinusoidalvoltageandsquarewaveoutputvoltagewaveforms(c)SinusoidalinputvoltageandsinusoidalcurrentwaveformsThishasbecomethemostpopulartypeofbrushlessservomotorcontrolServomotorControllersServomotorcontrollershavebecomemorethanjustamplifiersforaservomotorTodayservomotorcontrollersmustbeabletomakeanumberofdecisionsandprovideameanstoreceivesignalsfromexternalsensorsandcontrolsinthesystem,andsendsignalstohostcontrollersandPLCsthatmayinterfacewiththeservosystemFigureshowsapictureofseveralservomotorsandtheiramplifiersThecomponentsinthispicturelooksimilartoavarietyofothertypesofmotorsandcontrollersFigureshowsadiagramoftheservomotorcontrollersothatyoucanseesomeofthedifferencesfromothertypesofmotorcontrollersThecontrollerinthisdiagramisforaDCservomotorThecontrollerhasthreeportsthatbringsignalsinorsendsignalsoutofthecontrollerThepowersupply,中国工控信息网wwwcom收录servomotor,andtachometerareconnectedtoportPatthebottomofthecontrollerYoucanseethatthesupplyvoltageisvoltACsinglephaseAmaindisconnectisconnectedinserieswiththeLIwireTheLIandNlinessupplypowertoanisolationstepdowntransformerThesecondaryvoltageofthetransformercanbeanyvoltagebetweenandvoltsThecontrollerisgroundedatterminalYoushouldrememberthatthegroundatthispointisonlyusedtoprovideprotectionagainstshortcircuitsforallmetalpartsinthesystemTheservomotorisconnectedtothecontrolleratterminalsandTerminalisandterminalisTerminalprovidesagroundfortheshieldofthewiresthatconnectthemotorandthecontrollerThetachometerisconnectedtoterminalsandTerminalisandterminalisTheshieldforthiscableisgroundedtothemotorcaseThewiresconnectedtothisportwillbelargerthanwiresconnectedtotheotherports,sincetheymustbecapableofcarryingthelargermotorcurrentIfthemotorusesanexternalcoolingfan,itwillbeconnectedthroughthisportInmostcasesthecoolingfanwillbepoweredbysinglephaseorthreephaseACvoltagethatremainsataconstantlevel,suchasvoltsACorvoltsACFIGURE(a)Transistorsconnectedtothethreewindingsofthebrushlessservomotor(b)Waveformsofthethreeseparatevoltagesthatareusedtopowerthethreemotorwindings(c)Waveformsofthesignalsusedtocontrolthetransistorsequencethatprovides中国工控信息网wwwcom收录thewaveformsforthepreviousdiagram,(d)WaveformoftheoverallbackEMFFIGUREExampleservomotorsandamplifiers中国工控信息网wwwcom收录FIGUREDiagramofaservocontrollerThisdiagramshowsthedigital(onoff)signalsandtheanalogsignalsthataresenttothecontroller,andthesignalsthecontrollersendsbacktothehostcontrollerorPLCThecommandsignalissenttothecontrollerthroughportPITheterminalsforthecommandsignalareandTerminalisandterminalisThissignalisatypesignal,whichmeansthatitisnotgroundedordoesnotshareagroundpotentialwithanyotherpartofthecircuitSeveraladditionalauxiliarysignalsarealsoconnectedthroughportThesesignalsincludeinhibit(INH),whichisusedtodisablethedrivefromanexternalcontroller,andforwardandreversecommands(FACandRAC),whichtellthecontrollertosendthevoltagetothemotorsothatitwillrotateintheforwardorreversedirectionInsomeapplications,theforwardmaximumtravellimitswitchandreversemaximumtravellimitswitchareconnectedsothatifthemachinetravelmovestotheextremepositionsothatittouchestheovertravellimitswitch,itwillautomaticallyenergizethedrivetobegintravelintheoppositedirectionPortPIalsoprovidesseveraldigitaloutputsignalsthatcanbeusedtosendfaultsignalsorother中国工控信息网wwwcom收录informationsuchas"driverunning"backtoahostcontrollerorPLCPortPIbasicallyistheinterfaceforalldigital(onoff)signalsPortPistheinterfaceforanalog(max)signalsTypicalsignalsonthisbusincludemotorcurrentandmotorvelocitysignalsthataresentfromtheservocontrollerbacktothehostorPLCwheretheycanbeusedinverificationlogictoensurethecontrollerissendingthecorrectinformationtothemotorInputsignalsfromthehostorPLCcanalsobesenttothecontrollertosetmaximumcurrentandvelocityforthedriveInnewerdigitaldrives,thesevaluesarecontrolledbydriveparametersthatareprogrammedintothedrivePWMServoAmplifierThePWMservoamplifierisusedonsmallsizeservoapplicationsthatuseDCbrushtypeservomotorsFigureshowsadiagramforthistypeofamplifierFromthediagramyoucanseethatsinglephaseACpowerisprovidedtotheamplifierasthesupplyatthelowerleftpartofthediagramTheACvoltageisrectifiedandsenttotheoutputsectionofthedrivethatisshowninthetoprightcomerofthediagramTheoutputsectionofthedriveusesfourIGBTstocreatethepulsewidthmodulationwaveformTheIGBTsareconnectedsothattheyprovidevoltsDCanduptoAtothebrushtypeDCservomotorThepolarityofthemotorisindicatedinthediagramTheremainingcircuitsshowavarietyoffaultcircuitsinthemiddleofthediagramthatoriginatefromthefaultlogicboardandprovideanoutputsignalatthebottomofthediagramYoushouldnoticethatthefaultoutputsignalsincludeovervoltage,overtemperature,andovercurrentAfourthsignalisidentifiedasSSO(systemstatusoutput),whichindicatesthestatusofthesystemasfaultedanytimeafaulthasoccurredAjumperisusedtosettheSSOsignalasanopencollectoroutputwithalogiclevel""indicatingthedriveisready,orasanormallyclosedrelayindicatingthedriveisreadyTheinputterminalsatthebottomrightpartofthediagramareusedtoenableorinhibitthedrive,andtoselectforwardamplifierclamp(FAC)orreverseamplifierclamp(RAC)Theinhibitsignalisusedasacontrolsignal,sinceitinhibitstheoutputstageoftheamplifierifitishighTheFACandRACsignalslimitthecurrentintheoppositedirectiontoTheinputsignalsareshowninthediagramattheupperleftsideTheVCS(velocitycommandsignal)requiresaVCSandaVCSsignaltoprovidethedifferentialsignalApplicationsforServoAmplifiersandMotorsYouwillgetabetterideaofhowservomotorsandamplifiersoperateifyouseesometypicalapplicationsFigureshowsanexampleofaservomotorusedtocontrolapressfeedInthisapplicationsheetmaterialisfedintoapresswhereitiscutofftolengthwithaknifebladeorsheerThesheetmaterialmayhavealogoorotheradvertisementthatmustlineupregistrationmarkswiththecutoffpointInthisapplicationthespeedandpositionofthesheetmaterialmustbesynchronizedwiththecorrectcutoffpointThefeedbacksensorcouldbeanencoderorresolverthatiscoupledwithaphotoelectricsensortodeterminethelocationoftheregistrationmarkAnoperatorpanelisprovidedsothattheoperatorcanjogthesystemformaintenancetotheblades,orwhenloadinganewrollofmaterialTheoperatorpanelcouldalsobeusedtocallupparametersforthedrivethatcorrespondtoeachtypeofmaterialthatisusedThesystemcouldalsobeintegratedwitha中国工控信息网wwwcom收录programmablecontrollerorothertypeofcontrollerandtheoperatorpanelcouldbeusedtoselectthecorrectcutoffpointsforeachtypeofmaterialorproductthatisrunFIGUREDiagramofapulsewidthmodulator(PWM)amplifierwithabrushtypeDCservomotor中国工控信息网wwwcom收录FIGUREApplicationofaservomotorcontrollingthespeedofmaterialasitentersapressforcuttingpiecestosizeAnExampleofaServoControlledInLineBottleFillingApplicationAsecondapplicationisshowninFigInthisapplicationmultiplefillingheadslineupwithbottlesastheymovealongacontinuouslineEachofthefillingheadsmustmatchupwithabottleandtrackthebottlewhileitismovingProductisdispensedasthenozzlesmovewiththebottlesInthisapplicationnozzlesaremountedonacarriagethatisdrivenbyaballscrewmechanismTheballscrewmechanismisalsocalledaleadscrewWhenthemotorturnstheshaftoftheballscrew,thecarriagewillmovehorizontallyalongthelengthoftheballscrewshaftThismovementwillbesmoothsothateachofthenozzlescandispenseproductintothebottleswithlittlespillageTheservodrivesystemutilizesapositioningdrivecontrollerwithsoftwarethatallowsthepositionandvelocitytobetrackedastheconveyorlinemovesthebottlesAmasterencodertracksthebottlesastheymovealongtheconveyorlineAnaugerfeedsystemisalsousedjustpriortothepointwherethebottlesenterthefillingstationTheaugercausesaspecificamountofspacetobesetbetweeneachbottleasitentersthefillingstationThebottlesmaybepackedtightlyastheyapproachtheauger,butastheypassthroughtheaugertheirspaceissetexactlysothatthenecksofthebottleswillmatchthespacingofthefillingnozzlesAdetectorisalsoinconjunctionwiththedispensingsystemtoensurethatnoproductisdispensedfromanozzleifabottleismissingorlargespacesappearbetweenbottles中国工控信息网wwwcom收录FIGUREApplicationofabeveragefillingstationcontrolledbyaservomotorTheservodrivesystemcomparesthepositionofthebottlesfromthemasterencodertothefeedbacksignalthatindicatesthepositionofthefillingcarriagethatismountedtotheballscrewTheservodriveamplifierwillincreaseordecreasethespeedoftheballscrewmechanismsothatthenozzleswillmatchthespeedofthebottlesexactlyAnExampleofaServoControlledPrecisionAugerFillingSystemAthirdapplicationforaservosystemisprovidedinFigInthisapplicationalargefillingtankisusedtofillcontainersastheypassalongaconveyorlineThematerialthatisdispensedintothecontainerscanbeasinglematerialfilloritcanbeoneofseveralmaterialsaddedtoacontainerthatisdumpedintoamixerforablendingoperationSincetheamountofmaterialthatisdispensedintothecontainermustbeaccuratelyweighedandmeteredintothebox,anaugerthatiscontrolledbyaservosystemisusedThefeedbacksensorforthissystemcanbeaweighingsystemsuchastheloadcelldiscussedinearlierchaptersThecommandsignalcancomefromaprogrammablecontrollerortheoperatorcanenteritmanuallybyselectingarecipefromtheoperator'sterminalTheamountofmaterialcanbedifferentfromrecipetorecipe中国工控信息网wwwcom收录FIGUREApplicationofaprecisionaugerfillingstationcontrolledbyaservomotorThespeedoftheaugercanbeadjustedsothatitrunsathighspeedwhenthecontainerisfirstbeingfilled,andthespeedcanbeslowedtoapointwherethefinalgramsofmaterialcanbemeteredpreciselyasthecontainerisfilledtotheproperpointAsthepriceofmaterialincreases,precisionfillingequipmentcanprovidesavingsaswellasqualityintheamountofproductusedintherecipeAnExampleofaLabelApplicationUsingServomotorsThefourthapplicationhasaservomotorcontrollingthespeedofalabelfeedmechanismthatpullspreprintedlabelsfromarollandappliesthemtopackagesastheymoveonacontinuousconveyorsystempastthelabelingmechanismThefeedbacksignalsareprovidedbyanencoderthatindicatesthelocationoftheconveyor,tachgeneratorthatindicatesthespeedoftheconveyor,andasensorthatindicatestheregistrationmarkoneachlabelTheservopositioningsystemiscontrolledbyamicroprocessorthatsetstheerrorsignal,andtheservoamplifierthatprovidespowersignalstotheservomotorThisapplicationisshowninFigAnExampleofaRandomTimingInfeedSystemControlledbyaServomotorThefifthapplicationispresentedinFig,anditshowsaseriesofpackagingequipmentthatoperatesasthreeseparatemachinesThetimingcycleofeachstationofthepackagingsystemisindependentfromtheothersThepackagingsystemconsistsofaninfeedconveyor,apositioningconveyor,andawrappingstationTheinfeedconveyorandthewrappingstationaremechanicallyconnectedsothattheyrunatthesamespeedThepositionofthepackagesonthewrappingstationmustbestrictlycontrolledsothatthepackagesdonotbecometooclosetoeachotherApieceofmetalcalledaflightisconnectedtothewrappingstationconveyoratspecificpointstoensureeachpackage中国工控信息网wwwcom收录staysinpositionAsensorismountedatthebeginningofthepositioningconveyortodeterminethefrontedgeofthepackagewhenitstartstomoveontothepositioningconveyorAsecondsensorispositionedatthebottomofthepackagingconveyortodetecttheflightsBothofthesesignalsfromthesensorsaresenttotheservomotortoprovideinformationsotheservocanadjustthespeedofthepositioningconveyorsothateachpackagealignswithoneoftheflightsasitmovesontothepackagingconveyorThisapplicationshowsthattheservopositioningcontrollercanhandleavarietyofdifferentsignalsfrommorethanonesensorbecausethecontrollerusesamicroprocessorFIGUREExampleofalabelingapplicationcontrolledbyaservomotorFIGUREExampleofapackagingsystemwithrandomtimingfunctionscontrolledbyaservomotor

用户评价(0)

关闭

新课改视野下建构高中语文教学实验成果报告(32KB)

抱歉,积分不足下载失败,请稍后再试!

提示

试读已结束,如需要继续阅读或者下载,敬请购买!

文档小程序码

使用微信“扫一扫”扫码寻找文档

1

打开微信

2

扫描小程序码

3

发布寻找信息

4

等待寻找结果

我知道了
评分:

/12

伺服电机原理与应用

VIP

在线
客服

免费
邮箱

爱问共享资料服务号

扫描关注领取更多福利