基于plc的张力控制系统的发展英文翻译.doc

基于plc的张力控制系统的发展英文翻译.doc

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DevelopmentofPLC-basedTensionControlSystem

Abstract

Fiberwindingtensionisanimportantfactorinthemoldingtechniquesofcompositematerialwhichinfluencesthequalityofwindingproductdirectly,andthetensioncontrolisakeytechniqueinfiberwindingtechniques.Thispaperintroducesaclosed-looptensioncontrolsystemwiththeprogrammablelogiccontroller（PLC）withfunctionmodulesasitscontrolkernel,thealternatingcurrent（AC）servomotorasexecuteelementandtheradius-followingdevicetoaccomplishthereal-timeradiuscompensation.Themechanismofthetensioncontrolsystemisanalyzedandthenumericalmodelissetup.Thecompensationtechniqueoftheradiusofthescrollisanalyzed.Experimentalresultsshowthatthesystemiswellqualifiedwithhighcontrolprecisionandhighreactionspeed.

*Thecomponentsofcompositematerialfiberwindingpossesssuchadvantagesaslowweight,highstrength,andhighcorrosionresistance,andtheyarewidelyappliedinaviationandaerospaceindustry.Manyresearcheshaveshownthatimproperorunstabletensionleadstoastrengthlossof20%-30%ofthefiberwoundcomponents.Anidealtensioncontrolsystemshouldprovidestableandadjustabletensionduringthewindingprocess[1-3].

Withthedevelopmentofthewindingmachine,tensioncontrollershave,sofar,undergonethreestagesofdevelopment,i.e.,mechanicaltensioncontroller,electricaltensioncontrollerandcomputerizedtensioncontroller[4-5].Withthedevelopmentofelectronictechnologyandtheappearanceofthemicroprocessorofhighercostperformance,computerizedtensioncontrollercameintouse.Microprocessorbecomesthekernelofthecontrolsystemandthuscutsdownthenumberofcircuitsoftheelectroniccontrolsystem,whichgreatlysimplifiesthesystem,improvesitsreliabilityandmakespossibletheapplicationofadvancedcontrolmethods.Therefore,thistypeofcontrollersiswidelyused[6-7].

Thetensioncontroltechniquesarebecomingmatureandthespecificationsarebeingimprovedinsomedevelopedcountries.However,thefiberwindingindustryofChinastarteduplateandstilldropsbehindcomparedwiththewesterncountries.

Mechanicaltensioners,withlowprecisionandslowresponse,accountforthemainpartofdomestically-appliedtensioners,andcannotmeetthetensionrequirements.Therefore,thispaperpresentsaPLC-basedtensioncontrolsystem.

1Set-upoftheSystemScheme

1.1Constructionofthesystem

Awindingtensioncontrolsystemgenerallyconsistsofthreemainparts,namelytheunwinder,theprocesserandthewinder,anditmayalsoincludethemeasuringandcontrolparts,ancillarytransportapparatus,andaloadcell.Thetypeofthewinderandthatoftheunwindermaybeoneofthetwodrivetypes,surfacedriveorcenterdrive.Thesurfacedrivemeansthatascrollorbeltissetonthesurfaceofthewindingmaterialandthedriveforceisgeneratedthroughfriction.Thecenterdriveistosetadrivemechanismonthecentershaftofthescroll,wherethelinearspeedandthetensionforceofthewindingfibervarywiththeradiusofthescroll,leadingtotheso-called“scrollthick”[8].Thephenomenonof“scrollthick”makesthetensioncontrolverycomplex,butthecenterdrivemodeiswidelyappliedduetoitswideapplicability.

1.2Designoftensioncontrolscheme

Thissystemadoptsaschemewithacenterdriveandoutward-drawfiberconfiguration.SincetheoutputtorqueoftheACdigitalservomotorisindirectproportiontothefibertensionforceandthescrollradius,theoutputtorqueshoulddecreaseasthescrollradiusdecreasestoacquireaconstantfibertension.ThechangeofthescrollradiuscanbemeasuredbyaradiusfollowingdeviceandthesampledradiuschangethenpassesthroughananalogdigitalconverterandissenttothePLC.Byreadingthedesiredvalueofthetensionforce,theradiusandtensionforcearecalculatedwiththepresetcalculatingalgorithm.Thespeedinstructionandtorquelimitinstructionareissuedanddigital-to-analogconvertedtooutputtheanalogvoltagesignaltocontroltheservodriver.Theservodrivercontrolstherotatingspeedandoutputtorquetocontrolthefibertension.Theservomotor’sspeedandtorquearemeasuredbythepulseencoderandtheHallelementandfedbacktothePLCsystemtocomposeaclosedloopsystem.ThemechanismofthesystemisshowninFig.1.

Themaincomponentsinthesysteminclude

（1）APanasonicprogrammablecontroller（FP0-C10RS）,a12-bitFP0-A80andanFP0-A04V

ancilliaryconversionmodule.

（2）APanasonicACdigitalservodriverandservomotor.

（3）Aradius-followingdeviceincludingaradiusfollowingarmandarotarypotentiometer.

2MathematicalMode

Effectivecontrolofthefibertensionisrequiredinfiberwinding.Duetotheversatilityofthecoremoldshapeandwindingshape,thelinearspeedofthefiberisdifficulttobekeptconstantandthevariationprincipleisextremelycomplex.Therefore,theinfluenceofthespeedonthetensionforceshouldbetakenintoconsiderationinthemechanicalanalysisofthecontrolledobject.ThePLCwithfunctionmodulesasthecontrolsystem’scontrolkernel,andtheneededtensioncanbeenactedfromman-machineinterfacethroughtheserialcommunicationbetweenPLCanduppercomputer.Theinputoftheradiusvalue,thetorquefeedbackandthevelocityfeedback,therunningofthepresetcalculatingalgorithmandtheoutputofthesystemaredonebythePLCwithfunctionmodules.

Whentheunwinderisconsidered,thedynamictorqueequilibriumequationcanbeexpressedasfollows

M（t）=J（t）ω􀀅（t）+J􀀅（t）ω（t）+TR（t）+Mf+M0

（1）

whereTistheyarntension,R（t）isthereal-timescrollradius,M（t）istheresistantmomentoftheACservomotor,Mfistheviscousfrictionalmoment,ω（t）istheangularvelocityofthescroll,J（t）istherotatinginertiaofthescrollandtheyarnroll,andM0isthedryfrictionalmoment.

AsshowninEq.

（1）,thescrollradius,theresistantmoment,theangularvelocityoftheunwinderandtherotatinginertiaofthescrollareallfunctionsoftime,andthesystemisthusacomplexmultivariabletime-varyingsystem.

Propersimplificationofthetorqueequilibriumequationiscarriedoutwithclassicalcontroltheorybasedonthefollowingrules:

（1）Thedryfrictionalmomentandtheviscousfrictionalmomentareverylittleandmaybeignored.

（2）TheinfluenceofJ􀀅（t）ω（t）onthetensionforcemaybeignoredsincetheinstantaneousinertiachangesveryslightly.

（3）Thescrollradiusisreal-timemeasuredandfedbackbytheradiusfollowingdevice.Eq.

（1）isthensimplifiedas

TR（t）=M（t）+J（t）ω􀀅（t）

（2）

Therefore,thevariationsofscrolldiameterandscrollangularvelocityarethemaininfluencingfactorsoftheyarntension.

3CompensationoftheRadiusoftheScroll

Theradiuschangeofthescrollcausesthechangeofthescrollmoment,i.e.,thechangeoftheTR（t）inEq.

（2）.Oneendoftheradiusfollowingarmtouchesthescroll,andtheotherendisconnectedtotherotarypotentiometerviagearmagnifyingstructure,thustransformingachangeinthespindleradiustoachangeofvoltage,asshowninFig.2

whereListhelengthofradiusfollowingarm,Rmaxisthemaximumradiusofscroll,andR（t）istheinstantaneousscrollradius.

Supposethetransmissionratioofthegearisi,thentheangleofthesmallgearisgivenasφ=iθ

Forthepotentiometer,

whereUistheoutputvoltageofrotarypotentiometer,USisthepowersupplyvoltageofrotarypotentiometer,andφsisthetotalangleofrotarypotentiometer.

Trimmedas

4SoftwareDevelopmentoftheSystem

ThesoftwaredevelopmentmakesfulluseofthecapabilitiesofFP0-C10RS,thedigital-analogyI/Omodules,thehardwareandsoftwareresourcesofthePCcomputer.Theprecisionoftheanalog-digitalordigitalanalogconversiondependsonthenumberofbitsoftheanalog-digitalconverteranddigital-analogconverter.FP0-A80andFP0-A04Vbothare12bits,andtheresolutionis1/4000whentheoutputandinputrange–10V-+10V,whiletheFP0is16bits,sothecontrolresolutionofthesystemcanbeassured.Theoperationspeedofeachbasicinstructionis0.9μs/step,thus500stepsprogramneedsonly0.5ms,andtheconversionspeedsofFP0-A80andtheFP0-A40Vbothare1ms/channel,sothecontrolspeedofthesystemisassured.ThePLCladderdiagramisappliedtodevelopthewholecontrolprogram.However,theinputoftheparametersisnotintuitionistic,neitheristhedisplayofthereal-timetensionandthescrollradius.Inordertosolvethisproblem,acontrolprogramisdevelopedforthehostcomputerontheinterfaceofwhichtheoperatorcanperformtheinputoftheparameterandthedisplayofthereal-timetension,thespeedandthescrollradius.TheprogrammingportofalltheFPPLC’ssupportOPENMEWTOCOLPROTOCOL.UppercomputersendsaCOMMANDtoPLCasanASCLLstring.ThenthePLCautomaticallyreturnstheRESPONSEbasedontheCOMMAND.

Theinputsofthesystemarethevoltagefeedbackbyradiusfollowingdevice,thetorquefeedbackofalternatingnumericservo-electromotorandthevelocityfeedback.Theoutputofthesystemarealternatingnumericservo-electromotortorqueandvelocityvoltage.ThesoftwarecontrolflowofthetensioncontrolsystemisshowninFig.3.

5SimulationandExperimentalResults

Experimentalresearchofthetensioncontrolinrealwindingstateswascarriedoutthroughsimulatingtherealworkingcircumstancestotestthefeasibilityandcontrolprecision.Whenthetensionwassetto10N,theconstant-tensioncurveundersimulationandexperimentalconditionscanbeacquiredwithanearconstanttension,asshowninFig.4andFig.5,res