plc外文文献

DevelopmentofPLC-basedTensionControlSystemRENSheng-le*,LUHua,WANGYong-zhang,FUHong-yaDepartmentofMechanicalEngineering,HarbinInstituteofTechnology,Harbin150001,ChinaReceived22May2006;accepted22November2006AbstractFiberwindingtensionisanimportantfactorinthemoldingtechniquesofcompositematerialwhichinfluencesthequalityofwindingproductdirectly,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-upoftheSystemScheme1.1ConstructionofthesystemAwindingtensioncontrolsystemgenerallyconsistsofthreemainparts,namelytheunwinder,theprocesserandthewinder,anditmayalsoincludethemeasuringandcontrolparts,ancillarytransportapparatus,andaloadcell.Thetypeofthewinderandthatoftheunwindermaybeoneofthetwodrivetypes,surfacedriveorcenterdrive.Thesurfacedrivemeansthatascrollorbeltissetonthesurfaceofthewindingmaterialandthedriveforceisgeneratedthroughfriction.Thecenterdriveistosetadrivemechanismonthecentershaftofthescroll,wherethelinearspeedandthetensionforceofthewindingfibervarywiththeradiusofthescroll,leadingtotheso-called“scrollthick”[8].Thephenomenonof“scrollthick”makesthetensioncontrolverycomplex,butthecenterdrivemodeiswidelyappliedduetoitswideapplicability.1.2DesignoftensioncontrolschemeThissystemadoptsaschemewithacenterdriveandoutward-drawfiberconfiguration.SincetheoutputtorqueoftheACdigitalservomotorisindirectproportiontothefibertensionforceandthescrollradius,theoutputtorqueshoulddecreaseasthescrollradiusdecreasestoacquireaconstantfibertension.ThechangeofthescrollradiuscanbemeasuredbyaradiusfollowingdeviceandthesampledradiuschangethenpassesthroughananalogdigitalconverterandissenttothePLC.Byreadingthedesiredvalueofthetensionforce,theradiusandtensionforcearecalculatedwiththepresetcalculatingalgorithm.Thespeedinstructionandtorquelimitinstructionareissuedanddigital-to-analogconvertedtooutputtheanalogvoltagesignaltocontroltheservodriver.Theservodrivercontrolstherotatingspeedandoutputtorquetocontrolthefibertension.Theservomotor’sspeedandtorquearemeasuredbythepulseencoderandtheHallelementandfedbacktothePLCsystemtocomposeaclosedloopsystem.ThemechanismofthesystemisshowninFig.1.Themaincomponentsinthesysteminclude(1)APanasonicprogrammablecontroller(FP0-C10RS),a12-bitFP0-A80andanFP0-A04Vancilliaryconversionmodule.(2)APanasonicACdigitalservodriverandservomotor.(3)Aradius-followingdeviceincludingaradiusfollowingarmandarotarypotentiometer.2MathematicalModeEffectivecontrolofthefibertensionisrequiredinfiberwinding.Duetotheversatilityofthecoremoldshapeandwindingshape,thelinearspeedofthefiberisdifficulttobekeptconstantandthevariationprincipleisextremelycomplex.Therefore,theinfluenceofthespeedonthetensionforceshouldbetakenintoconsiderationinthemechanicalanalysisofthecontrolledobject.ThePLCwithfunctionmodulesasthecontrolsystem’scontrolkernel,andtheneededtensioncanbeenactedfromman-machineinterfacethroughtheserialcommunicationbetweenPLCanduppercomputer.Theinputoftheradiusvalue,thetorquefeedbackandthevelocityfeedback,therunningofthepresetcalculatingalgorithmandtheoutputofthesystemaredonebythePLCwithfunctionmodules.Whentheunwinderisconsidered,thedynamictorqueequilibriumequationcanbeexpressedasfollowsM(t)=J(t)ω�