外文翻译--矫正扁轧制品现代化设备的自动化 英文版.pdf

ThecompanySeverstalcompletedthesuccessfulintroductionofnewinlineplatestraighteningmachinesPSMsonits2800and5000millsinAugust20031,2,3.ThemaindesignfeaturesofthemachinesareasfollowseachmachineisequippedwithhydraulicholddownmechanismstoimprovethedynamicsandaccuracyofthemachineadjustmentsandmorereliablymaintainaconstantgapthemachineshavemechanismstoindividuallyadjusteachworkrollerwiththeaidofhydrauliccylindersthisbroadenstherangeofstraighteningregimesthatcanberealizedbyprovidingameasureofcontroloverthechangeinthecurvatureoftheplateeachworkrollerisprovidedwithitsownadjustabledrivetoeliminaterigidkinematicconstraintsbetweenthespindlesthesystemofrollersofthePSMisenclosedincassettestofacilitaterepairsandreducerollerreplacementcoststhePSMhasasystemthatcanbeusedtoadjustthemachinefromaninerollerstraighteningschemetoafiverollerschemeinwhichthedistancebetweentherollersisdoubledthisisdonetowidentherangeofplatethicknessesthatthemachinecanaccomodate.Thus,thenewstraighteningmachineisasophisticatedmultifunctionsystemofmechanismsthatincludesawiderangeofhydraulicallyandelectricallydrivencomponentscontrolledbydigitalandanalogsignals.TheentirecomplexofPSMmechanismscanbedividedintotwofunctionalgroupsthemaingroup,whichincludesthemechanismsthatparticipatedirectlyinthestraighteningoperationtheholddownmechanisms,themechanismsthatindividuallyadjusttherollers,themechanismsthatadjustthecomponentsfordifferentstraighteningregimes,themechanismthatmovesthetoprollerofthefeeder,andthemaindrivetheauxiliarygroupwhichincludesthecassettereplacementmechanism,thespindlelockingmechanism,andtheequipmentthatcoolsthesystemofrollers.AlthoughthePSMhasalargenumberofmechanisms,theuseofmodernhydraulicandelectricdriveshasmadeitpossibletoalmostcompletelyautomatethemainandauxiliaryoperationsperformedonthePSMandtheunitsthatoperatewithit.Describedbelowarethefeaturesandtheautomaticcontrolsystemsforthemostimportantmechanismsoftheplatestraighteningmachine.Theoperatingregimesofthosemechanismsarealsodiscussed.ThehydraulicholddownmechanismsHHMsofthesheetstraighteningmachinefunctionintwomainregimestheadjustmentregimetheregimeinwhichthespecifiedpositionsaremaintained.Therearecertainrequirementsforthecontrolsystemandcertainefficiencycriteriaforeachregime.Intheadjustmentregime,thecontrolsystemforthehydraulicholddownmechanismsmustdothefollowingsynchronizethemovementsofthehydrauliccylindersandkeeptheangulardeeflectionwithinprescribedlimitsmaximizespeedinadjustingthemachineforanewplatesizemaintainahighdegreeofaccuracyinpositioningthemechanismsMetallurgist,Vol.48,Nos.7–8,2004AUTOMATINGTHECONTROLOFMODERNEQUIPMENTFORSTRAIGHTENINGFLATROLLEDPRODUCTSYu.N.Belobrov,V.G.Smirnov,A.I.Titarenko,V.A.Perekhodchenko,andI.L.SinelnikovUDC621.982NovokramatorskMachinePlantAO.TranslatedfromMetallurg,No.8,pp.51–56,August,2004.406Thecontrolsystemhasthefollowingrequirementswhenoperatinginthemaintenanceregimestabilizethecoordinatesofthetopcassetteandthetoprollerofthefeederwithahighdegreeofaccuracyminimizethetimeneededtoreturntheequipmenttotheprescribedcoordinateswhendeviationsoccursuchasduetotheforceexertedbyaplatebeingstraightened.Needforsynchronization.ExperienceinoperatingtheplatestraighteningmachineinplateshopNo.3atSeverstalhasshownthatthemostproblematicfactorinadjustingthemachineisthenonuniformityoftheforcesappliedtothehydrauliccylinders.ThisnonuniformityisduetotheasymmetricdistributionofthemassesofthemovingpartsofthePSMinparticular,theeffectoftheweightofthespindleassembly.Displacementofthehydrauliczeropointrelativetotheelectricalzeropointintheservovalvesisalsoacontributingfactor.Thelatterreasonismoresignificant,thesmallerthevolumeofthehydrauliccylinder.Thus,theHHMofthetoprollerofthefeederisthemostsensitivetodriftofthezeropoint.Therearealsootherfactorsthataffectthedynamism,simultaneousness,andsynchronismoftheoperationoftheholddownmechanismsdifferentiationofthefrictionalforcesonpartsofthehydrauliccylindersduetodifferentcombinationsofdeviationsinthedimensionsofthematedparts,despitethenarrowtolerancesdifferencesinthespringingcharacteristicsandtheindicescharacterizingtheinertiaofthehydraulicsupplychannelsduetodifferencesinthelengthsofthepipesleadingfromtheservovalvestothehydrauliccylinders.Thus,sincethePSMisnotequippedwithdevicestomechanicallysynchronizetheoperationofthecylinders,thetransmissionofsignalsofthesameamplitudetotheinputsoftheservovalvesinevitablyresultsinaspeeddifferencethatcanseriouslydamagethemechanisms.Tominimizeandeliminatetheeffectsoftheabovementionedfactors,wedevelopedanalgorithmforelectricalsynchronizationoftheholddownmechanisms.TheHHMofthetopcassette,composedoffourholddowncylindersandfourbalancingcylinders,isdesignedtoensuremobileadjustmentofthemachinetosettherequiredsizeofstraighteninggapinaccordancewiththethicknessoftheplateandmaintainthatgapwithaspecifiedaccuracyinthepresenceandabsenceofaloadonthehousingsfromthestraighteningforce.Thehydraulicsystemoftheholddownmechanismisdesignedinsuchawaythatonlyonechamberofthehydrauliccylindersisusedastheworkingchamber.Thesecondchamberisalwaysconnectedtothedischargechannel.Thetopcassetteisloweredwhenthebalancingforcesareovercomebytheholddowncylinders.Thecassetteisraisedonlybytheactionofthebalancingcylinders.Thisarrangementhasmadeitpossibletoeliminategapsinthepositioningoftheequipment.407Fig.1.Blockdiagramofthecontrolsystemofthehydrauliccylinder.Thehydrauliczeropointisthepositionthattheslidevalveoccupieswhenitcoversthedeliveryanddischargemains.Theelectricalzeropointisthecontrolsignalthatshouldmovethevalvetothehydrauliczeropoint.Thesepointsshouldideallycoincide,butinactualservovalveswithzerooverlapthereisalwaysacertainamountofdisplacementthatresultsinleakageofthehydraulicfluid.TheHHMofthetoprollerofthefeederconsistsoftwohydrauliccylinders.Hydraulicfluidisfedintotheplungerchamberwhentherolleristobeloweredandisfedintotherodchamberwhenitistoberaised.ControlPrinciples.IndividualcircuitshavebeenprovidedFig.1tocontrolthehydrauliccylindersoftheholddownmechanisms.ThecontrolsignalXctlsenttotheinputoftheservovalveisformedbyaproportionalintegralPIcontrollertoimprovethesensitivityofthesystem,wechosetousevalveswithzerooverlap.ThesignalsenttotheinputofthecontrollertheerrorsignalXerrisformedasthedifferencebetweenthecontrolpointsignalforpositionXcptandthefeedbacksignalXf.b.ThelattersignalisreceivedfromthelineardisplacementgageGofthegivenhydrauliccylinder.ThegagesoftheHHMforthetopcassettearebuiltintothebalancinghydrauliccylindersHCs.Thecylindersareinstalledinsuchawaythattheirmovementscanbeconsideredtobeequaltothedisplacementsofthecorrespondingcylinderrods,withallowanceforcertaincoefficients.ThegagesintheHHMforthetoprollerofthefeederareincorporateddirectlyintotheholddowncylinders.Theintegralpartofthecontrollerisactivatedonlyduringthefinaladjustmentstageandduringstabilizationoftheprescribedcoordinate.Whenthedisplacementsexceedacertainthresholdvalue,thefunctionsofthePIcontrolleraretakenoverbyaproportionalPcontrollerwiththetransferfunctionWsk.Thus,XctltkXerrt.Whentherearesignificantdifferencesbetweenthedisplacementsoftheworkingrollers,thedifferenceerrorbetweenthecontrolpointandthefeedbacksignalfromthelineardisplacementgagereachesvaluesgreatenoughsothattheoutputsignalwhichcontrolstheoperationoftheservovalvereachesthesaturationzone.Inthiscase,furtherregulationofthedisplacementrateand,thussynchronizationofthemovementsofthecylindersbecomesimpossibleaslongastheerrorexceedsthevalueatwhichXctlisgreaterthantheboundaryvalueforthesaturationzoneXsat.Thelimitingerror–thelargesterrorforwhichXctldoesnotreachsaturation–isinverselyproportionaltothegainofthecontrollerkXerrXsat/k.SolvingthegivenproblembydecreasingkleadstoalossofspeedintheadjustmentofthePSMandadecreaseincontrolaccuracyduringthestraighteningoperation.Thus,tokeepthecontrolsignalfromreachingthesaturationzonewhentherearesubstantialdisplacements,thesystemwasdesignedsothattheinputofthecontrollerisfednottheactualrequiredvalueXrqbutanincrementDXofamagnitudesuchthattheconditionkDXXsatissatisfied.ThecontrolpointisincreasedbytheamountDXafterthepositionofthecylinderhasbeenchangedbytheamountcorrespondingtotheincrementhavingthelargestlagrelativetothecylindersdirectionofmotion.TheadjustmentofthecontrolpointiscontinueduntilthedifferencebetweentherequiredvalueandtheactualpositionofthemechanismbecomeslessthantheincrementXrq–Xf.bDX.ThentheinputofthecontrollerisfedthevalueXcpt,whichisequaltotherequiredadjustmentXcptXrq.Theadjustmentisthuscompleted.Useoftheprincipleofasteppedincreaseinthecontrolpointmakesitpossiblesynchronizethemovementsofthecylindersandsetthecontrolpointwithahighdegreeofaccuracyforalmostanyidealrepetitionfactor.MechanismsforIndividualAdjustmentoftheWorkingRollers.Theplatestraighteningmachineisdesignedsothateachworkingrollercanbemovedvertically,whichisdonebymeansofahydrauliccylinderactinginconcertwithaVbeltdrive.Thecylindersaresuppliedwithpowerfromservovalvesoperatedwithproportionalcontrol.Alineardisplacementgageisbuiltintoeachcylindertoobtainafeedbacksignalonthepositionoftheroller.Sincethesegagesareactuallytransmitinginformationonthepositionofthecylinderrodsratherthantheworkingrollersthemselves,thefollowingconversionisperformedtoobtaintherollerscoordinatesXrolkredXf.b,wherekredisthegearratioofthedriveXf.bisthepositionofthecylinderrodmeasuredbythelineardisplacementtransducers.Thus,apositionfeedbackcircuitisprovidedtocontrolthepositionofeachworkingroller.Figure1presentsadiagramofoneofthecircuits.ThecontrolsignalsaregeneratedbymeansofthePIcontrollere,whichhasmadeitpossibletoachieveahighdegreeofaccuracyinadjustingthesystemwithoutsacrificingspeed.408Theindividualdriveoftherollers.Theabovedescribeddesignisbasedontheuseofindividualacdriveswithmotorsofdifferentpowersfedfromfrequencyconverters.Eachindividualdriveoffersthefollowingadvantagesoveragroupdrivegreaterreliabilitythankstotheabsenceofadditionalloadsonthecomponentsofthemechanismsduetodifferencesbetweenthelinearvelocitiesoftheworkingrollersandthespeedoftheplatethepossibilitythatthemachinecouldcontinuetooperateifoneorevenseveraldrivesmalfunctioninthiscase,thecorrespondingrollerswouldberemovedfromthestraighteningzonethepossibilitythatthelinearvelocitiesoftherollerscouldbeindividuallycorrectedinaccordancewiththeactualspeedoftheplatesuchacorrectioncouldbemadeeitherasapreliminarymeasureonthebasisofmeasuredandcalculatedvaluesorduringthestraighteningoperationonthebasisofthedataobtainedfromthefrequencyconverters,whichemployartificialintelligence.Themaindriveofthestraighteningmachinerotatesninestraighteningrollersandtwohousingrollers.Thisdrivemustbehighlyreliableinoperation,sincethefactthatthePSMisinstalledinthemilllinemeansthatsizableproductionlossescanbeincurredifthedrivefailstoworkproperlyevenforashortperiodoftime.Therequirementsthatmustbesatisfiedbythedrivearedeterminedbytheoperationalanddesignfeaturesofthemachineasawholetheplatebeingstraightenedmustcreatearigidkinematiccouplingbetweenthestraighteningrollers,therollersofthehousing,andtheadjacentsectionsoftherollerconveyorstheplateshouldundergoelongationduringthestraighteningoperationasaresultofplasticdeformation,withtheincrementsinlengthbeingdifferentoneachworkingrollerduetothedifferentiationofthebendingradiithissituationleadstoanonuniformincreaseinthespeedoftheplateasitmovestowardtheendofthePSMitmustbepossibletouseworkingrollersofdifferentdiametersthisbeingdone,forexample,duetononuniformwearorregrindingtheloadsontherollersshouldbedifferentiatedinaccordancewiththechosenstraighteningregimereversestraighteningshouldbepossible.Inlightoftheabovefactorsandtheactualoperatingregimesoftheplatestraighteningmachinebeingdiscussedhere,thefollowingrequirementscanbeestablishedfortheelectricdriveregulationofspeedwithinbroadlimits,includingstartupofthemotorsunderloadoperationinthereverseregimearigidcharacteristicwƒMhighdegreeofaccuracyinmaintainingtheprescribedspeedfullysynchronousoperation.Theelementbase.Thedriveoftherollerswasbuiltwiththeuseofasynchronousthreephasemotorshavingashortcircuitrotor.ThemotorsweredesignedbytheGermancompanyVEM.Theycancontinuetofunctionundersevereoverloadsandarereliableinoperation.ThemotorsarecontrolledbySIMOVERTfrequencyconvertersmadebytheGermanfirmSiemens.Theirmodulardesignfacilitatesmaintenanceandrepair,andthepresenceofabuiltinmicroprocessorblockmakesitpossibletoexecutemostofthefunctionsinvolvedincontrollingtheoperationofthedrivemaintaintheprescribedspeedwithahighdegreeofstability,recalculatethefrequencyofrotationinaccordancewiththeactualdiametersoftherollers,diagnosetheconditionofthedrive,controlthedrivesoperation,andexchangeinformationonthePROFIBUSnetwork.Motorsofdifferentpowersareusedinthesystembecauseofthedifferentiateddistributionofthemomentsbetweentheworkingrollers.Usingdifferentmotorshasmadeitpossibletosignificantlyreducethecostoftheelectricalequipmentandimprovetheperformancecharacteristicsofthemachineasawhole.Themachinehasthreemainoperatingregimestheworkingregimesemiautomaticandautomatic,thetransportregime,andthecassettereplacementregime.Figure2showsablockdiagramoftheoperationsconnectedwithrealizationoftheworkingregime.Inthesemiautomaticvariantofthisregime,theoperatorcontrolsthePSMfromacontrolpanel.Inthiscase,theoperatorcandothefollowingchoosethestraighteningregimefromadatabasecorrectthechosenregimeadjusttheregimemanually,which409