外文翻译新型直动式压电电液伺服阀复合控制方法.docx

外文翻译新型直动式压电电液伺服阀复合控制方法.docx

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外文翻译新型直动式压电电液伺服阀复合控制方法

中文3450字

附二:

外文翻译

HighPreciseControlMethodforaNewTypeof

PiezoelectricElectro—hydraulicServoValve

Abstract：

Anewtypeofpiezoelectricelectro-hydraulicservovalvesystemwasproposed．Andthenmultilayerpiezoelectricactuatorbasedonnewpiezoelectricceramicmaterialwasusedastheelectricity-machineconverteroftheproposedpiezoelectricelectro-hydraulicservovalve.Theproposedpiezoelectricelectro-hydraulicservovalvehasascendantperformancecomparedwithconventionalones.Butthesystemisofhighnonlinearityanduncertainty,itcannotachievefavorablecontrolperformancebyconventionalcontrolmethod．Todevelopanefficientwaytocontrolpiezoelectricelectro—hydraulicservovalvesystem．Ahigh—precisefuzzycontrolmethodwithhysteresisnonlinearmodelinfeedforwardloopwasproposed.Thecontrolmethodisseparatedintotwoparts：

afeedforwardloopwithPreisachhysteresisnonlinearmodelandafeedbackloopwithhigh-precisefuzzycontro1.ExperimentalresultsshowthatthehysteresisloopandthemaximumoutputhysteresisbythePIDcontrolmethodare4.22％and2．11pm,respectively；thehysteresisloopandthemaximumoutputhysteresisbytheproposedcontrolmethodrespectivelyare0．74％and0．37μm，respectively；themaximumtrackingerrorbythePIDcontrolmethodforsinewavereferencesignalisabout5．02％,themaximumtrackingerrorbytheproposedcontrolmethodforsinewavereferencesignalisabout0．85％．contro1．

Keywords：

piezoelectricelectro—hydraulicservovalve；hysteresisnonlinearity；Preisachmodel；fuzzycontrol

1Introduction

Electro—hydraulicservosystemiswidelyappliedinindustrialdomainnowadays．forexample．robotdrive，machinebuilding,architecturalengineering．Theelectro-hydraulicservovalveisthekerneloftheelectro-hydraulicservosystem,anditsperformancehasdecisiveeffectOfthewholesystem．Theconventionaldrivemodeofelectro．hydraulicservovalvehaslowerresolutionandnarrowerworkbandwidth，whichrestrictstheapplicationsoftheelectro-hydraulicservovalve．Theproposedpiezoelectricelectro-hydraulicservovalveadoptsmultilayerpiezoelectricactuatoraselectricity-machineconverter.ThisHewtypeofpiezoelectricelectro-hydraulicservovalvehasbetterdynamicperformancethanthatofconventionalones．

Atpresent，withtheresearchandthedevelopmentofnew-typeactuatorbasedonnewtypematerials,itispossibletomakethenewelectricity-machineconverterwithhighfrequency.Newmaterialsincludepiezoelectricceramicmaterials,magnetostrjctivematerials,shapememoryalloys．Thereinto,multilayerpiezoelectricactuatorsbasedonnewpiezoelectricceramicmaterialshavemanymeritssuchassmallcubage，highresolution，highfrequencyandlargedriveforce．Hence，theyarewidelyusedinthemicro-positiondeviceofmachinetoolsandotherprecisionmachines[1-6]．However,theyalsohavemanyshortcomings，forexample，hysteresisnonlinearitymodelinfeedforwardloopwasproposed．

2Workprincipleandcharacteristicofnew-typeofpiezoelectricelectro-hydraulicValve

Becausethepullingforcecapacityofmultilayerpiezoelectricactuatorisverypoor,itcannotmaketheslidevalveoftheelectro,hydraulicservovalvebidirectionallvmove.Twomultilayerpiezoelectricactuatorswereadoptedtosolvethisproblem[7-8].Theshortcomingofthismethodishighcostandsystemisdifficulttocontro1.Utilizingtherestoringforceofaleafspring，onemultilayerpiezoelectricactuatorcanrealizebidirectionalmovementoftheslidevalveinthispaper.Whenthevoltageimposedonmultilayerpiezoelectricactuator1sincreased，multilayerpiezoelectricactuatorwillelongateanddrivetheslidevalvetomovetowardstheleft，whichmakestheleafspringdeform．Onthecontrary,whenthevoltageimposedonmultilayerpiezoelectricactuatorisreduced，multilayerpiezoelectricactuatorwillbeshortenedandthendrivetheslidevalvemovetowardstherightbytheactionoftherestoringforceoftheleafspring.

Thestructureofnewtypeofpiezoelectricelectro—hydraulicservovalveisshowninFig．1．

Theinput-outputcharacteristicofthenewtypeofpiezoelectricelectro-hydraulicservovalvesystemindicatesthatithashysteresisnonlinearitywithnonloca1memory（seeFig．2）.AtanyreachablepointL（Ua，Ya）ininput-outputdiagram，thenumberofalternativecurvethatdescribesthefuturepathofhysteresisnonlinearitywithnonloca1memoryisinfinite.Namely,thefutureoutputofthesystemdependsnotonlyonthecurrentoutputYaandfutureinput，butalsoonthepasthistoryofinputvalue’sextremum.Hence,theoutputresponseofnewtypeofpiezoelectricelectro-hydraulicservovalvetoanappliedinputvoltagebecomesunpredictable.

Inthesystem，thereexistothernonlinearitiessuchasforceoffrictionandworkdeadzoneofvalve,furthermore，dampingcoefficientandoiltemperaturearealsochangedwithtime．Thenonlinearityanduncertaintyhaveseriouslyeffectsonthepositionprecision.Toimprovetheperformanceofthenewtypeofpiezoelectricelectro-hydraulicservovalvesystem,avalidcontrolmethodisneeded

3Controlalgorithm

Atpresent,conventionalPIDcontrolleriswidelyappliedinindustrialcontroldomainbecauseofitssimplecontrolstructure,easydesignandinexpensivecost．However,conventionalPIDcontrollerisdifficulttoachievegoodcontrolperformanceinthenewtypeofpiezoelectricelectro,hydraulicservovalvesystembecausethecontrolobjecthashighnonlinearityanduncertainty．Fuzzycontrollershowsgoodresultsinthecaseofcontrollinghighnonlinearsystems.However,conventionalfuzzycontrollerisessentiallyakindofnonlinearPDcontroller,thereexistssteadystateerror,whichcannotmeetthedemandofhighpreciseofthesystem．Inthispaper,ahigh-precisefuzzycontrolalgorithmwithPreisachhysteresisnonlinearmodelinfeedforwardloopwasproposed．TheblockdiagramofthecombinedcontrolisshowninFig．3．

ThecontrolsystemiscomposedofafeedforwardloopbasedonPreisachmodelandafeedbackloopofhighprecisefuzzycontroller．Ul（istheoutputoffeedforwardloopbasedonPreisachmode1．Asalinearterm,itisselectedfromaPreisachfunctiontablebasedonthegivenpositionvalue．U2（istheoutputofthehighprecisefuzzycontroller．ThesumU（t）offeedforwardcontrolvoltagefandfeedbackcontrolvoltageU2（t），asultimatecontrolvoltage，isactedonnewtypepiezoelectricelectro-hydraulicservovalve.

3．1FeedforwardloopbasedonPreisachmodel

Theopenloopresponseofthenewtypepiezoelectricelectro-hydraulicservovalvesystemunderanarbitraryandnon-cyclicinputsignalisshowninFig．2．Thisphenomenonappearsashysteresisnonlinearitywithnonlocalmemory,whichcanbepredictedbyPreisachmode1．ThenumericalformofPreisachmodelcanbe

writtenasfoliows：

（1）

Eqn.

（1）canbeusedtocalculatetheresponseofthenewtypeofpiezoelectricelectro-hydraulicservovalvesubjecttoaknownarbitraryinputvoltagesequence．Aseriesoffirstorderfunctions

ofthenewtypeofpiezoelectricelectro-hydraulicservovalveareexperimentallydetermined．Theprocedureisasfollows．

ThespacebetweenzeroandsaturationvoltageUsisdividedintonequipartitions,andthevoltageofeveryequantpointiskUs／n，wherek=-0，1，2，⋯n．

VoltageisappliedfromzerotoeveryequantpointkUs／n，andthendecreasedtozero．Inthisprocess，thepositionoutputvaluesofthenewtypeofpiezoelectricelectro-hydraulicservovalvearerecordedateveryequantpointbetweenzeroandsaturationvoltageUs，therewith，

andthePreisachfunctiontableareobtained（seeFig．4），

（2）

Basedonthedrivervoltagerangeofthenewtypeofpiezoelectricelectro．hydraulicservovalve，thecoordinatespaceisselectedas0≤

≤l50Vand0≤

<150VFromFig．4，thelimittriangleisdividedintoseveralsquaresandtriangles．Decreasingthesizeofthesquaresandtrianglesisexpectedtoincreasetheaccuracyofthemode1,however,itwillspendmassivecomputationaltime．Basedontheexperiments,nisselectedas5，namely,thesizeofeachofsidesofthesquaresandtrianglesisselectedas30V.

BasedonthegivenpositionvalueandthenumericalformofthePreisachmodel，

or

canbeobtained．Thereby,basedonPreisachfunctiontable，thecontrolvoltageUl（t）isobtainedwhen

liesontheverticallineor

liesonthehorizontalline．FortheinexistencevoltageinthePreisachfunctiontable．itcanbeobtainedbythelinearinterpolation．

Incomparisontoaconventionalfeedbackcontroller,themainadvantageofthismode1-basedfeedforwardcontrolleristhatitcancompensatethehysteresisnonlinearityofthesystemandachievehighlydynamicoperationatthesametime,andnoadditionalsensorisneeded．Thisleadstoaverysimpleandinexpensivecontrolsystem．Themaindrawbackofthefeedforward

controllerissensitivetounmodeldataandunconsideredexternaldisturbancessuchastemperaturedrift．Foranewtypeofpiezoelectricelectro—hydraulicservovalvesystemthatneedshighcontrolprecision．mode1．basedfeedforwardcontrollercannotobtaingoodcontroleffect．Thenacompoundcontrolmethodwithfeedforwardandfeedbackcontrolprojectwasproposedinthispape.Inthefeedbackcontrolloop，ahigh—precisefuzzycontrolalgorithmwasadopted．Themethodcanobtaingoodperformance．

3．2Highprecisefuzzycontrol

Conventionalfuzzycontrollerhastwoinputvariables，eandΔe，andoneoutputvariable（U），theyareerror,changeoferrorandoutputcontroloffuzzycontroller．Inthenewtypeofpiezoelectricelectro-hydraulicservovalvesystem，thephysicalrangeoftheslidevalvepositionerror（andchangeoferror（△e）are[-x，x]and[-Δx，Δx]，respectively．Thecorr