基于plc的张力控制系统的发展(英文翻译)

DevelopmentofPLC-basedTensionControlSystemAbstractFiberwindingtensionisanimportantfactorinthemoldingtechniquesofcompositematerialwhichinfluencesthequalityofwindingproductdirectly,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-upoftheSystemSchemeConstructionofthesystemAwindingtensioncontrolsystemgenerallyconsistsofthreemainparts,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(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)isthensimplifiedasTR(t)=M(t)+J(t)ω(t)(2)Therefore,thevariationsofscrolldiameterandscrollangularvelocityarethemaininfluencingfactorsoftheyarntension.3CompensationoftheRadiusoftheScrollTheradiuschangeofthescrollcausesthechangeofthescrollmoment,i.e.,thechangeoftheTR(t)inEq.(2).Oneendoftheradiusfollowingarmtouchesthescroll,andtheotherendisconnectedtotherotarypotentiometerviagearmagnifyingstructure,thustransformingachangeinthespindleradiustoachangeofvoltage,asshowninFig.2whereListhelengthofradiusfollowingarm,Rmaxisthemaximumradiusofscroll,andR(t)istheinstantaneousscrollradius.Supposethetransmissionratioofthegearisi,thentheangleofthesmallgearisgivenasφ=iθForthepotentiometer,whereUistheoutputvoltageofrotarypotentiometer,USisthepowersupplyvoltageofrotarypotentiometer,andφsisthetotalangleofrotarypotentiometer.Trimmedas4SoftwareDevelopmentoftheSystemThesoftwaredevelopmentmakesfulluseofthecapabilitiesofFP0-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.3.5SimulationandExperimentalResultsExperimentalresearchofthetensioncontrolinrealwindingstateswascarriedoutthroughsimulatingtherealworkingcircumstancestotestthefeasibilityandcontrolprecision.Whenthetensionwassetto10N,theconstant-tensioncurveundersimulationandexperimentalconditionscanbeacquiredwithanearconstanttension,asshowninFig.4andFig.5,respectively.InordertoknowtheworkstateoftheACservomotorwhenthetensionchanges,thetensionforcewaschangedfrom5Nto10NandthevariationcurvesofwhichareshowninFig.6andFig.7undersimulationandexperimentalconditions,wheretheovershootingandfluctuationarerathersmallandtheresponsetimeislessthan0.3s.5.1AnalysisofstaticdifferencerateStaticdifferencerateisaveryimportantindexforevaluatingtheperformanceofthesystem.ItcanbeexpressedasfollowswhereΔT=Tmax−Tmin,Tmaxisthemaximumtension,Tministheminimumtension,andTmistheaveragetension.TheanalysisofstaticdifferencerateoftensionisshowninTable1.Table1Theanalysisofstaticdifferencerateoftension5.2AnalysisoffluctuationrateWhetherthetensionfluctuatingratemeetstherequirementsisakeyindexforevaluatingtheperformanceofthedesignedtensioncontrolsystem.Enactedainitializedyarntension,aftercompensationcalculation,outputit.Then,testtheactualtensionandfindoutthemaximumandminimumtensions.6ConclusionsSimulationandexperimentalresultsshowthatthesystemisfeasiblewiththePLCasthekernel,theACdigitalservomotorastheexecuteelementandaradiusfollowingdevicetoperformtheradiuscompensation.Thecharacteristicsofthesysteminclude(1)APanasonicFP-seriesPLCandfunctionalmodulesserveasthecontrolkernels.Thesmallvolume,highintegrity,highreliability,excellentcontrolcapabilityandthelowcostallmakethesystemconvenientandcompactwithhighenoughreliabilityandprecision.(2)Theyarn-retakingdevicecanbeleftout,becausetheservomotorcanperformthesamefunction.(3)Themodularizedsoftwaredesignfacilitatestheconstructionexpansionandthesecondarydevelopmentofthecustomers.(4)ThefriendlyprogrammingenvironmentofthePanasonicFPWIN_GRsoftwareencapsulatesthecapabilityofon-lineprogramming.Parameterscanbechangedonlineandthecontroleffectscanbeseeninstantaneously.基于plc的张力限制系统的发展摘要光纤弯曲力是复合材料影响成型工艺质量的一个重要因素弯曲的产品干脆张力器是纤维缠绕工艺的关键技术技巧。本文介绍了闭环张力限制系统与可编程逻辑限制器(PLC)和功能模块为限制核心,沟通电(AC)伺服电机为执行要件、radius-following装置,实现实时半径补偿。机理的张力限制系统进行了分析,并对其数值模型。补偿技术的半径滚动进行了分析。试验结果表明,在较高的限制精度和很高的反应速度下，系统是合格的。复合材料纤维缠的成分绕具有重量轻、强度高,抗腐蚀性等优点,广泛应用于航空、航天工业。很多探讨表明,不正确或不稳定的张力导致纤维损伤的部件有20%-30%的强度损失。缠绕过程中一个志向的张力限制系统将供应固定和可调的张力[1-3]。在绕线机的发展下,到目前为止,张力限制器经验了三个发展阶段,即:机械张力限制器、电气张力限制器和计算机化的张力限制器[4-5]。随着电子技术的发展，微处理器拥有了更高的性能价格比,计算机化的张力限制器也起先运用了。微处理器成为限制系统的内核,从而降低了电路的数量的电子限制系统,大大简化了系统,有可能应用先进的限制方法改善了其牢靠性。因此,这种类型的限制器得到了广泛的应用[6-7]。张力限制技术正在走向成熟，在一些发达国家其规格也正在提高。然而，中国的弯曲光纤产业起步较晚，仍旧落后于西方国家。精度低、反应慢机械张力器件，主要面对国内的运用张力器的市场，不能满意张力要求。因此，本文反映了基于plc的张力限制系统。1、该系统的结构方案1.1系统架构一个弯曲张力限制系统大体上由三部分组成，即放卷机、处理器和卷取机，也包括测量与限制部分，协助运输装置和测力传感器。放卷机和卷取机是两种驱动类型之一，表面驱动模式或者中心驱动模式。表面驱动模式指一个卷轴或者带子起先于弯曲材料的表面，驱动力通过摩擦产生。中间驱动模式是卷轴杆上的中心轴的滚动，缠绕纤维的线速度和张力随着卷轴的半径变更而变更，这导致了所谓的“滚动厚”。这种现象使张力限制特别困难，但是中间驱动模式因其广泛应用性而被广泛应用。1.2设计张力限制方案这个系统采纳中心驱动的方案和外拉纤维配置。因为沟通数字伺服电动机的输出转矩和纤维张力以与卷轴半径成比例，所以输出转矩应当随着卷轴半径减小到要求的恒定纤维张力。一种测量半径的装置和取样的半径变更可以测量卷轴半径的变更，通过模拟数字整流器，卷轴半径变更被发送给PLC。通过读取张力的期望值，预算法则可以计算出半径和张力。系统发布了速度指令和转矩限制指令，并把它们转换成能限制伺服驱动的输出模拟电压信号。伺服驱动限制系统限制着转速和限制纤维张力的输出转矩。脉冲编码器和霍尔开关可以测量伺服电动机的速度和转矩，并把速度和转矩反馈给构成闭环循环系统的PLC系统。这种系统的原理如图1所示。系统中的主要成分包括（1）一个日本松下可编程限制器（2）一个日本松下空调沟通数字伺服驱动和伺服电动机（3）一个测量半径的装置和旋转电位计2、数学模型在纤维缠绕中对张力的有效限制是必要的。由于模型和弯曲形态的多样性，张力线速度难以保持不变，变分原理也相当困难。因此，在机械分析被控对象时，我们应当考虑张力速度的影响。通过PLC和计算机的串行通信，在人机接口处，可以制定PLC的功能模块如限制系统的限制核心以与所需的张力。PLC的功能模块可以计算出输出半径、转矩和速率反馈、预算法则的规律和系统的输出。考虑退绕机时，动态扭矩的平衡方程式可以表示如下M(t)=J(t)ω(t)+J(t)ω(t)+TR(t)+Mf+M0（1）此处T是纱线张力，R(t)是实时滚动半径，M(t)是沟通伺服电动机的粘滞摩擦力矩，J(t)是卷轴的旋转惯性，以与M0是干摩擦力矩。如公式（1）所示，实时滚动半径、力矩、角速度和卷