基于PLC的张力控制系统的发展

ChineseJournalofAeronauticsChineseJournalofAeronautics20(2007)266-271*,LUHua,WANGYong-zhang,FUHong-yaDepartmentofMechanicalEngineering,HarbinInstituteofTechnology,Harbin150001,ChinaReceived22May2006;accepted22November2006AbstractFiberwindingtensionisanimportantfactorinthemoldingtechniquesofcompositematerialwhichinfluencesthequalityofwindingproductdirectly,andthetensioncontrolisakeytechniqueinfiberwindingtechniques.Thispaperintroducesaclosed-looptensioncontrolsystemwiththeprogrammablelogiccontroller(PLC)withfunctionmodulesasitscontrolkernel,thealternatingcurrent(AC)servomotorasexecuteelementandtheradius-followingdevicetoaccomplishthereal-timeradiuscompensation.Themechanismofthetensioncontrolsystemisanalyzedandthenumericalmodelissetup.Thecompensationtechniqueoftheradiusofthescrollisanalyzed.Experimentalresultsshowthatthesystemiswellqualifiedwithhighcontrolprecisionandhighreactionspeed.Keywords:tensioncontrol;PLC;numericalcontrolwindingmachine;ACdigitalservomotor*Thecomponentsofcompositematerialfiberwindingpossesssuchadvantagesaslowweight,highstrength,andhighcorrosionresistance,andtheyarewidelyappliedinaviationandaerospaceindustry.Manyresearcheshaveshownthatim-properorunstabletensionleadstoastrengthlossof20%-30%ofthefiberwoundcomponents.Anidealtensioncontrolsystemshouldprovidestableandadjustabletensionduringthewindingprocess[1-3].Withthedevelopmentofthewindingmachine,tensioncontrollershave,sofar,undergonethreestagesofdevelopment,i.e.,mechanicaltensioncon-troller,electricaltensioncontrollerandcomputer-izedtensioncontroller[4-5].Withthedevelopmentofelectronictechnologyandtheappearanceofthemicroprocessorofhighercostperformance,com-puterizedtensioncontrollercameintouse.Micro-processorbecomesthekernelofthecontrolsystemandthuscutsdownthenumberofcircuitsoftheelectroniccontrolsystem,whichgreatlysimplifies*Correspondingauthor.Tel.:[phone].E-mailaddress:[e-mail]:NationalNaturalScienceFoundationofChina(50175020)thesystem,improvesitsreliabilityandmakespos-sibletheapplicationofadvancedcontrolmethods.Therefore,thistypeofcontrollersiswidelyused[6-7].Thetensioncontroltechniquesarebecomingmatureandthespecificationsarebeingimprovedinsomedevelopedcountries.However,thefiberwind-ingindustryofChinastarteduplateandstilldropsbehindcomparedwiththewesterncountries.Mechanicaltensioners,withlowprecisionandslowresponse,accountforthemainpartofdomes-tically-appliedtensioners,andcannotmeettheten-sionrequirements.Therefore,thispaperpresentsaPLC-basedtensioncontrolsystem.1Set-upoftheSystemScheme1.1ConstructionofthesystemAwindingtensioncontrolsystemgenerallyconsistsofthreemainparts,namelytheunwinder,theprocesserandthewinder,anditmayalsoin-cludethemeasuringandcontrolparts,ancillarytransportapparatus,andaloadcell.ThetypeofthewinderandthatoftheunwindermaybeoneoftheRENSheng-leetal./ChineseJournalofAeronautics20(2007)266-271·267·twodrivetypes,surfacedriveorcenterdrive.Thesurfacedrivemeansthatascrollorbeltissetonthesurfaceofthewindingmaterialandthedriveforceisgeneratedthroughfriction.Thecenterdriveistosetadrivemechanismonthecentershaftofthescroll,wherethelinearspeedandthetensionforceofthewindingfibervarywiththeradiusofthescroll,leadingtotheso-called“scrollthick”[8].Thephenomenonof“scrollthick”makesthetensioncontrolverycomplex,butthecenterdrivemodeiswidelyappliedduetoitswideapplicability.1.2DesignoftensioncontrolschemeThissystemadoptsaschemewithacenterdriveandoutward-drawfiberconfiguration.SincetheoutputtorqueoftheACdigitalservomotorisindirectproportiontothefibertensionforceandthescrollradius,theoutputtorqueshoulddecreaseasthescrollradiusdecreasestoacquireaconstantfi-bertension.Thechangeofthescrollradiuscanbemeasuredbyaradiusfollowingdeviceandthesam-pledradiuschangethenpassesthroughanana-log-digitalconverterandissenttothePLC.Byreadingthedesiredvalueofthetensionforce,theradiusandtensionforcearecalculatedwiththepre-setcalculatingalgorithm.Thespeedinstructionandtorquelimitinstructionareissuedanddigi-tal-to-analogconvertedtooutputtheanalogvoltagesignaltocontroltheservodriver.Theservodrivercontrolstherotatingspeedandoutputtorquetocon-trolthefibertension.Theservomotor’sspeedandtorquearemeasuredbythepulseencoderandtheHallelementandfedbacktothePLCsystemtocomposeaclosedloopsystem.ThemechanismofthesystemisshowninFig.1.Fig.1Principleoftensioncontrolsystem.Themaincomponentsinthesysteminclude(1)APanasonicprogrammablecontroller(FP0-C10RS),a12-bitFP0-A80andanFP0-A04Vancilliaryconversionmodule.(2)APanasonicACdigitalservodriverandservomotor.(3)Aradius-followingdeviceincludingara-diusfollowingarmandarotarypotentiometer.2MathematicalModelEffectivecontrolofthefibertensionisre-quiredinfiberwinding.Duetotheversatilityofthecoremoldshapeandwindingshape,thelinearspeedofthefiberisdifficulttobekeptconstantandthevariationprincipleisextremelycomplex.There-fore,theinfluenceofthespeedonthetensionforceshouldbetakenintoconsiderationinthemechanicalanalysisofthecontrolled