已阅读5页,还剩1页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
ANoise-FreeServo-SpindleforHigh-speedNCGearGrindingMachinesTakashiEmura,LeiWang,HisashiNakamura,MasashiYamanakaandYasushiTeshigawaraDepartmentofMechatronicsandPrecisionEngineering,TohokuUniversityAoba,Aramaki,Aobaks,Sendai,980-77JapanAbstract-TheauthorsdevelopedaproductivetypeNC(NumericallyControlled)geargrindingmachineforautomobileplants,ThisNCma-chinerequireshigh-accuracysynchronizationbetweenthegrindingspin-dleandworkspindle.Wemustusehigh-powerservomotorsandservo-amplifierstosatisfythespecificationrequiredforhigh-speedgrinding.However,sincethehigh-powerservo-amplifiercausesverylargerippleofmotorcurrentatPWM(Pulse-WidthModulation)frequencyandin-ducesstrongnoise,itbecomesdifficulttogetthestablesynchronousrota-tionamongspindles.Therefore,theauthorstriedtousetwo-phasetypePUtoachievenoise-freehigh-speedsynchronousspindlesandtoreducethenoisecausedbythecurrentripplewithakindofcurrentfilter.Inthispaper,anapproachforsuppressingthenoiseandexperimentalresultsaredescrlbed.I.INTRODUCTIONGeargrindingtakesextremelylonggrindingtimeanditpre-ventsincreasingtheproductivityinmassproductionofgears.Thus,theauthorsdevelopedaproductivetypeNCgeargrind-ingmachineforautomobileplants,whicharethemostproduc-tiveplantsofgears.Thismachinerequirestwolarge-powerservo-spindlesforitsgrinding-spindleandworkspindle.heseservo-spindlesalsohavetobesynchronouslycontrolledwithhighprecisionevenrotatingatahighspeed.Theauthorsusedhigh-powerandhigh-speedservomotorstodrivethespindles.Forexample,theservomotorforgrinding-spindlehasaratedpowerof22kW,ratedoutputtorqueof22N-mandmaximumrotaryspeedof10000r/min.Theservomotorforworkspindlehasaratedpowerof16kW,ratedoutputtorqueof82N.mandmaximumrotaryspeedof2000r/min.TheseservomotorsaredrivenbyPWM(Pulse-WidthMod-ulation)typeservo-amplifiers,andthePWMtypeamplifieroflargepowercausesaverylargerippleinmotorcurrentwhichappearsatPWMfrequency.Sincethislargecurrentripplein-ducesastrongnoisewhichcausestroubletocontrolsystems,itisdifficulttorealizesynchronouscontrolofhighaccuracy.Therefore,theauthorstriedtousetwo-phasetypePLL(Phase-LockedLoop)togetnoise-freehigh-speedsynchronousspin-dlesandtriedtouseakindofcurrentfiltertoreducetherippleofmotorcurrent.Experimentswerecarriedouttoconfirmtheef-fectivenessofthenoise-freesystems.Inthispaper,anapproachforsuppressingthenoiseandgettingthehigh-speedandhigh-precisionsynchronousspindlesisdescribedwithexperimentalresults.11.NOISECAUSEDBYPWMProblemsofnoiseofthegrinding-spindleismoreseverethanthatoftheworkspindlebecausetheratedpowerofthegrinding-spindleislargerthanthatoftheworkspindle.Thuswemainly0-7803-3026-9195$4.0001995IEEEdescribeaboutthecaseofgrinding-spindleinthefollowings.Thegrinding-spindleisdrivenbyahigh-powerbrushlessser-vomotor.Sincethemaximumoutputvoltageoftheservo-amplifierislimitedto200Vandtheratedpoweroftheser-vomotoris22kW,thecurrentoffieldcoilhastobemorethan200Aatapeakload.Forthislargecurrent,awirediameteroffieldcoilbecamelarge,andthenumberofturnsbecameafewbecauseofthelimitationofwindingspace.Thusinductanceofthefieldcoilwasconstrainedtoaverysmallvalue.Themea-suredinductanceofonephaseisabout30pHatlkHzanditisreducedtoverysmallvalueoflessthan1.5pHat25kHzofPWMfrequency.Sincethecoilinductanceisextremelysmalllikethis,itselectricaltimeconstantisverysmall.Thismeansthatwecangetagoodcontrolcharacteristics.However,theextremelyshorttimeconstantcausesverylargecurrentrippleatPWMfrequency,andthiscurrentrippleinducesthestrongnoise.Thestrongnoisegivesseriousproblemstocontrolsys-tems.Inordertoanalyzetheripplecurrent,numericalsimulationofmotorcurrentwascarriedout.Fig.l(a)issimplifiedmodelofsynchronousmotorforsimulation,wherecoilinductanceLis1.44pH,coilresistanceRis0.15SZandvoltageofDClineEis200V.PWMoutputvoltageEu,EvandEwofservo-amplifieraresuppliedonterminalofthreephasesU,V,W.PWMpatternshowninFig.l(b)aregeneratedbycompar-ingreferencevoltageeu,eVandewwithtrianglewaveegofwhichfrequencyis25kHz.Fig.2(a)isanexampleofsimulatedresults,wheretheout-putfrequencyoftheservo-amplifieris300Hz.AsshowninFig.2(a),motorcurrentisoverlappedbylargenoise.Fig.2(b)givesthedetailsituationbyconiparingsimulatedandmeasuredresultsofcoilcurrent,wheresimulatedresultsagreedwiththemeasuredresults.Thusthesimulatedresultsshowsthatthemo-torcurrenthasverylargecurrentrippleatPWMfrequency.Thissimulationshowsclearlythattheservomotorandpoweramplifiergenerateverystrongnoisesforthesakeofsmallnessofcoilinductance.Thecoilinductancedecreasessharplyathighswitchingfrequencyinsuchlargepowermotorbecauseofthemagneticcharacteristicoffieldcore.ThenoisescausedbyswitchingisaverysevereprobleminthisNCmachineandhastobeovercomeinordertoachievethehighprecisionsyn-chronouscontrol.Therefore,thefollowingsectionsdescribetwodifferentap-proachesforovercomingswitchingnoiseproblem.SectionHIpresentsasynchronouscontrolmethodoftwo-phasetypePLLwhichenablesthesystemengageahigh-precisionandhigh-692UEvWEUEVEW(b)Fig.1.Vu,V,V,arebackEMF(electromotiveforce)Motormodelfornumericalsimulation.I,I,I,arelinecurrentandn3EsUEV.I,I-1001I.I.I.I.II0123Time(ms)(a)Simulatedmotorcurrent.InITime(2Opddiv)(b)Comparisonofsimulatedandmeasuredresults.Fig.2.Rippleofmotorcurrent.speedsynchronouscontrolunderstrongnoisesituation.Sec-tionIVgivesdiscussionofusinglargepowerfiltertosuppressswitchingnoiseandtheexperimentalresults.111.SYNCHRONOUSSYSTEMBYTWO-PHASETYPEPLLThedevelopedgeargrindingmachinerequireshigh-speedsyn-chronouscontrolwithhighaccuracy.Thehigh-speedandhigh-precisionsynchronouscontrolsystemsarerealizedusuallybyusingahigh-resolutionandhigh-speedencoderwhoseoutputistwo-phasesinusoidalwave.However,thevoltageofthesinusoidalwavesisusuallyverysmall,anditisdifficulttodetectthissmallvoltagewithoutproblemsofthenoiseunderthestrongnoisesurroundings.Thismeansthatwecannotusetheconventionalcontrolmethodofhigh-precisionsynchroniza-tion.Therefore,theauthorsusedtwo-phasetypePLLinthissynchronoussystem.Thetwo-phasetypePLLwasfirstpro-posedbyEmuralanditsnoiserejectionabilitywasalreadyverified2-4.Fig.3isblockdiagramofthehigh-speedsynchronoussys-tembetweengrindingspindleandworkspindleoftheNCgeargrindingmachine.Bothoftheservo-spindleswerecontrolledbytwo-phasetypePLL.Acommandpulsegeneratorgeneratestwopulsetrainswhosefrequencyratioisthevelocityratioofgrinding-spindletoworkspindle.Positioncontrollersoftwo-phasetypePLLcontrolthespindlessoasforthemtofolloweachcommandpulseaccurately.Byusingtwo-phasetypePLL,high-speedandhigh-precisionsynchronouscontrolwasreal-ized.Twointerpolatorsoftwo-phasetypePLLinterpolateen-codersignalwithhighresolutionandtheinterpolatedoutputpulsesofrotationalanglearesenttoservo-amplifiers.A.High-resolutiondetectionofrotaryanglewithinterpolatoroftwo-phasetypePLLTheservo-amplifierswhichweusedthistimerequireatwo-phaserectangularsignalforgeneratingthethree-phasefieldcurrentthatsynchronizeswithrotorangle.However,wecouldnotusetheconventionalinterpolatorsofcomparatortypebe-causeofthenoiseinducedbytheripplecurrent.Therefore,theauthorsdesignedspecialinterpolatorswhichusetwo-phasetypePLLasshowninFig.4todetectrotaryanglesofspindles.Circuitsofthisinterpolatorwasdesignedmainlyaccordingtothedescriptionin3,andsotheyareonlybrieflydescribedinthefollowing.Inputsignalisatwo-phasesinusoidalwave(sin&,cosBi)obtainedfromencoder.Atrackingsignaloftwo-phasesinu-soidalwave(sine,cos0,)isgeneratedbyavoltagecontrolledoscillator(VCO).ThisVCOiscontrolledsoastotrackthein-putsignal.Phasedifferenceofinputsignalandtrackingsig-naliscalculatedbyphasedetector(PD).Loopfilter(LF)re-moveshigh-frequencycomponentsofoutputofPDandoutputtoVCO.V/FconvertercontainedinVCOgeneratespulsetrain693Commandpulsegenerator&pulsedistributorr1IcontrollerWorkoieceOpticalencoder/.Fig.3.Ahigh-spxdsynchoussystemforNCgeagrindingmachines.InputFig.4.Blockdiagramofinterpolatorusingtw-phasetype.PLL.withthefrequencyproportionaltoinputvoltage.Thepulsetrainsiscountedwithabinarycounter,andtheoutputofcounterisfedtoaROM.Two-phasesinusoidalwaveindigitalvalueiswrittenintheROManditisoutputwhenaddressed.D/Acon-vertersconverttheROMoutputtoanalogvoltage.Thesinu-soidalwaveiscontrolledsoastotrackinputoftwophasesinu-soidalsignalbycontrollingthephasedifferenceto0,thismeansthatPLLisinlockedstate.Underthelockedstate,pulsefromV/Fbecomestotheinterpolatedpulseofinputsignalwhichistherotaryangleofencoder.Themostsignificantdifferenceoftwo-phasetypePLLfromconventionalPLListhatwecanalwaysobtainthetrue2-phasesinusoidalwavewhichtracksinputsignal.Thismeansthatithasexcellentnoisesuppressioncharacteristicsandwiderangeofinputfrequency.Thiscircuitcanalsolockwhenmotorchangesitsrotarydirection.Opticalencodersofveryhighprecisionareusedtodetectro-taryangleofshaft.Numberofopticalslitsis1800forgrinding-spindleand9000forworkspindle.Wecanget2-phasesinu-soidalwavesfromtheencoders.Thedevelopedinterpolatordividesthemby128timesandoutput2-phaserectangularpulsesignal.Hencetheresolutionis5.6and1.1respectively,andthemaximumfrequencybecomesupto38.4MHz.Thepulsesarefedtopoweramplifiersandaswellusedtomonitorsyn-chronouscontrol.In3,amagneticscalewithinductiontypeheadwasusedastherotarysensor.Becauseinductiontypeheadcannotworkatlowspeed,theinterpolatorcouldnotworkatrotaryspeedbelow300r/min.However,thenewlydevelopedsystemcanworkatanyspeedbelow10000r/mforgrindingspindleandbelow2000r/minforworkspindle.Ofcourse,wecangivereversiblerotationstothespindles.Ingeneral,detectionwithsohighaccuracyandhighfre-quencyiscriticallyaffectedbynoisesanditisverydifficulttorealizestablecontrol.However,thenewinterpolatorscande-tecttherotorangleswithoutmisoperation.Fig.5illustratesanexampleofexperimentalresults.InFig.5,inputsignalmeanssignalobtainedfromencoderandtrackingsignalmeansthesinusoidalwaveofVCO.AsshowninFig.5,signalfromencoderisdistortedbystrongnoise.However,thesinusoidalwavewhichispreciselytrackingtheinputsignalhasnodistor-tion,becauseitisgeneratedbyVCOwhoseoutputwaveformistruesinusoidalwave.WecangettheinterpolatedpulsesfromtheoutputpulsesofV/Fconverter,bywhichthetrackingsinu-soidalwaveswereconstructed.B.Servo-ControllerwithTwo-PhaseTypePLLServo-controllerusesthetwo-phasetypePLLmethodaswell.TheschematicisshowninFig.6.Aservo-errorde-694Time)Fig.5.Experimentalresultsofinterpolatoroftwo-phasetypePLL.(Workspindle,500rhnin)sine,Asine,ServoServo+f1amplifierIMotor6sine,Fig.6.Schematicofservomechanismoftwo-phasetypePLL.tectoroftwo-phasetypePLLisusedtodetectservo-errorwithveryhighprecision.PIDcontrollercontrolsthemotortorquetomaketheservo-errorto0.Referencesignalofthisloopisapairoftwo-phasesinusoidalwaves(sin8;,cose;),andtheirphaseiscomparedwiththetwo-phasesinusoidalwavesobtainedfromencoderbythefollowingvectorphaseoperation.cos8icos8,-sin8;sin0,=cos8d-cos8;sin8,+sin8;cos8,=sin8d(1)*Hencewecangetapairoftwo-phasesinusoidalwavesofwhichargumentisphasedifferenceBd=8;-8,.Sincewecandetectthephasedifference8dwiththesameprincipleastheinterpola-tormentionedpreviously,theservo-errordetectoroftwo-phasetypePLLdetectstheservo-errorwithhighresolutionandhighaccuracy.Anotherfeatureofthisloopisthattheservo-errordetectorisabletodetectangularvelocityerrorwithhighaccuracy.ThisisbasedontheexcellentcapabilityofPLLinfrequencydetectionasknown.Byfeedbackoftheangularvelocityerro
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 2024年02月福建省漳平市中小学幼儿园2024年公开招聘41名新任教师工作笔试参考题库后附答案详解
- 2024年02月泉州市公办学校2024年公开招聘1924名编制内新任教师410笔试参考题库后附答案详解
- 2024年02月江苏省常熟市事业单位2024年公开招聘126名工作人员304笔试参考题库后附答案详解
- 2024年02月广西来宾市总工会2024年招考2名工作人员笔试参考题库后附答案详解
- 2024年02月国家统计局来宾调查队(广西)2024年公开招考2名编外工作人员笔试参考题库后附答案详解
- 2024年02月上海市第一社会福利院2024年公开招聘工作人员笔试参考题库后附答案详解
- 湖北省黄石市阳新县2022-2023学年六年级下学期期中语文试卷
- 《文王有声》原文与鉴赏
- 全国自考00230《合同法》全真模拟演练(二)
- 2024年4月江苏苏州宿迁工业园区校园招考聘用事业编制教师12人笔试参考题库附带答案详解
- 血生化血常规的意义课件
- 《青蛙写诗》课件
- 小学民族团结校本教材教案(低年级)
- IEC国内技术对口单位
- 金碟ERPK3系统实验指导书
- 门头施工方案
- 医院绩效考核指标库
- 加州65法案:1986安全饮用水及毒性物质禁用准则
- GB∕T 37452-2019 海洋平台起重机钢丝绳选型方法
- 小学数学奥数举一反三3年级(全)
- 18 小猴子下山 生字讲解 (10张PPT)
评论
0/150
提交评论