矫直机中英文对照外文翻译文献.docx
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矫直机中英文对照外文翻译文献.docx
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矫直机中英文对照外文翻译文献
中英文资料翻译
原文:
AUTOMATINGTHECONTROLOFMODERNEQUIPMENTFORSTRAIGHTENINGFLAT-ROLLEDPRODUCTS
ThecompanySeverstal’completedthesuccessfulintroductionofnewin-lineplate-straighteningmachines(PSMs)onits2800and5000millsinAugust2003[1,2,3].Themaindesignfeaturesofthemachinesareasfollows:
●eachmachineisequippedwithhydraulichold-downmechanisms(toimprovethedynamicsandaccuracyofthemachineadjustmentsandmorereliablymaintainaconstantgap);
●themachineshavemechanismstoindividuallyadjusteachworkrollerwiththeaidofhydrauliccylinders(thisbroadenstherangeofstraighteningregimesthatcanberealizedbyprovidingameasureofcontroloverthechangeinthecurvatureoftheplate);
●eachworkrollerisprovidedwithitsownadjustabledrive(toeliminaterigidkinematicconstraintsbetweenthespindles);
●thesystemofrollersofthePSMisenclosedincassettes(tofacilitaterepairsandreducerollerreplacementcosts);
●thePSMhasasystemthatcanbeusedtoadjustthemachinefromanine-rollerstraighteningschemetoafive-
●rollerschemeinwhichthedistancebetweentherollersisdoubled(thisisdonetowidentherangeofplatethick-nessesthatthemachinecanaccomodate).
Thus,thenewstraighteningmachineisasophisticatedmulti-functionsystemofmechanismsthatincludesawiderangeofhydraulicallyandelectricallydrivencomponentscontrolledbydigitalandanalogsignals.TheentirecomplexofPSMmechanismscanbedividedintotwofunctionalgroups:
themaingroup,whichincludesthemechanismsthatpartici-patedirectlyinthestraighteningoperation(thehold-downmechanisms,themechanismsthatindividuallyadjusttherollers,themechanismsthatadjustthecomponentsfordifferentstraighteningregimes,themechanismthatmovesthetoprollerofthefeeder,andthemaindrive);theauxiliarygroup(whichincludesthecassettereplacementmechanism,thespindle-lock-ingmechanism,andtheequipmentthatcoolsthesystemofrollers).AlthoughthePSMhasalargenumberofmechanisms,theuseofmodernhydraulicandelectricdriveshasmadeitpossibletoalmostcompletelyautomatethemainandauxiliaryoperationsperformedonthePSMandtheunitsthatoperatewithit.
Describedbelowarethefeaturesandtheautomaticcontrolsystemsforthemostimportantmechanismsoftheplate-straighteningmachine.Theoperatingregimesofthosemechanismsarealsodiscussed.Thehydraulichold-downmechanisms(HHMs)ofthesheet-straighteningmachinefunctionintwomainregimes:
theadjustmentregime;theregimeinwhichthespecifiedpositionsaremaintained.Therearecertainrequirementsforthecontrolsystemandcertainefficiencycriteriaforeachregime.
Intheadjustmentregime,thecontrolsystemforthehydraulichold-downmechanismsmustdothefollowing:
●synchronizethemovementsofthehydrauliccylindersandkeeptheangulardeeflectionwithinprescribedlimits;
●maximizespeedinadjustingthemachineforanewplatesize;
●maintainahighdegreeofaccuracyinpositioningthemechanisms;
Fig.1.Blockdiagramofthecontrolsystemofthehydrauliccylinder.
Thecontrolsystemhasthefollowingrequirementswhenoperatinginthemaintenanceregime:
●stabilizethecoordinatesofthetopcassetteandthetoprollerofthefeederwithahighdegreeofaccuracy;
●minimizethetimeneededtoreturntheequipmenttotheprescribedcoordinateswhendeviationsoccur(suchasduetotheforceexertedbyaplatebeingstraightened).
Needforsynchronization.Experienceinoperatingtheplate-straighteningmachineinplateshopNo.3atSeverstal’hasshownthatthemostproblematicfactorinadjustingthemachineisthenonuniformityoftheforcesappliedtothehydrauliccylinders.ThisnonuniformityisduetotheasymmetricdistributionofthemassesofthemovingpartsofthePSM(inparticular,theeffectoftheweightofthespindleassembly).Displacementofthe“hydrauliczeropoint”relativetothe“electricalzeropoint”intheservovalvesisalsoacontributingfactor.Thelatterreasonismoresignificant,thesmallerthevolumeofthehydrauliccylinder.Thus,theHHMofthetoprollerofthefeederisthemostsensitivetodriftofthezeropoint.
Therearealsootherfactorsthataffectthedynamism,simultaneousness,andsynchronismoftheoperationofthehold-downmechanisms:
●differentiationofthefrictionalforcesonpartsofthehydrauliccylindersduetodifferentcombinationsofdeviationsinthedimensionsofthematedparts,despitethenarrowtolerances;
●differencesinthe“springing”characteristicsandtheindicescharacterizingtheinertiaofthehydraulicsupplychannels(duetodifferencesinthelengthsofthepipesleadingfromtheservovalvestothehydrauliccylinders).
Thus,sincethePSMisnotequippedwithdevicestomechanicallysynchronizetheoperationofthecylinders,theransmissionofsignalsofthesameamplitudetotheinputsoftheservovalvesinevitablyresultsinaspeeddifferencethatcanseriouslydamagethemechanisms.
Tominimizeandeliminatetheeffectsoftheabove-mentionedfactors,wedevelopedanalgorithmforelectricalsynchronizationofthehold-downmechanisms.
TheHHMofthetopcassette,composedoffourhold-downcylindersandfourbalancingcylinders,isdesignedtoensure
mobileadjustmentofthemachinetosettherequiredsizeofstraighteninggap(inaccordancewiththethicknessoftheplate)and
maintainthatgapwithaspecifiedaccuracyinthepresence.
andabsenceofaloadonthehousingsfromthestraighteningforce.
Thehydraulicsystemofthehold-downmechanismisdesignedinsuchawaythatonlyonechamberofthehydrauliccylindersisusedastheworkingchamber.Thesecondchamberisalwaysconnectedtothedischargechannel.Thetopcassetteisloweredwhenthebalancingforcesareovercomebythehold-downcylinders.Thecassetteisraisedonlybytheactionofthebalancingcylinders.Thisarrangementhasmadeitpossibletoeliminategapsinthepositioningoftheequipment.
TheHHMofthetoprollerofthefeederconsistsoftwohydrauliccylinders.Hydraulicfluidisfedintotheplungerchamberwhentherolleristobeloweredandisfedintotherodchamberwhenitistoberaised.
ControlPrinciples.Individualcircuitshavebeenprovided(Fig.1)tocontrolthehydrauliccylindersofthehold-downmechanisms.Thecontrolsignal(Xctl)senttotheinputoftheservovalveisformedbyaproportional-integral(PI)controller(toimprovethesensitivityofthesystem,wechosetousevalveswith“zero”overlap).Thesignalsenttotheinputofthecontroller(theerrorsignalXerr)isformedasthedifferencebetweenthecontrol-pointsignalforposition(Xcpt)andthefeedbacksignal(Xf.b).Thelattersignalisreceivedfromthelineardisplacementgage(G)ofthegivenhydrauliccylinder.
ThegagesoftheHHMforthetopcassettearebuiltintothebalancinghydrauliccylinders(HCs).Thecylindersareinstalledinsuchawaythattheirmovementscanbeconsideredtobeequaltothedisplacementsofthecorrespondingcylinderrods,withallowanceforcertaincoefficients.ThegagesintheHHMforthetoprollerofthefeederareincorporateddirectlyintothehold-downcylinders.
Theintegralpartofthecontrollerisactivatedonlyduringthefinaladjustmentstageandduringstabilizationoftheprescribedcoordinate.Whenthedisplacementsexceedacertainthresholdvalue,thefunctionsofthePIcontrolleraretakenoverbyaproportional(P)controllerwiththetransferfunctionW(s)=k.Thus,Xctl(t)=kXerr(t).
Whentherearesignificantdifferencesbetweenthedisplacementsoftheworkingrollers,thedifference(error)betweenthecontrolpointandthefeedbacksignalfromthelineardisplacementgagereachesvaluesgreatenoughsothattheoutputsignalwhichcontrolstheoperationoftheservovalvereachesthesaturationzone.Inthiscase,furtherregulationofthedisplacementrateand,thussynchronizationofthemovementsofthecylindersbecomesimpossibleaslongastheerrorexceedsthevalueatwhichXctlisgreaterthantheboundaryvalueforthesaturationzone(Xsat).Thelimitingerror–thelargesterrorforwhichXctldoesnotreachsaturation–isinverselyproportionaltothegainofthecontrollerk:
Xerr SolvingthegivenproblembydecreasingkleadstoalossofspeedintheadjustmentofthePSMandadecreaseincontrolaccuracyduringthestraighteningoperation.Thus,tokeepthecontrolsignalfromreachingthesaturationzonewhentherearesubstantialdisplacements,thesystemwasdesignedsothattheinputofthecontrollerisfednottheactualrequiredvalue(Xrq)butanincrement(∆X)ofamagnitudesuchthattheconditionk∆X Xrq–Xf.b<∆X. ThentheinputofthecontrollerisfedthevalueXcpt,whichisequaltotherequiredadjustment: Xcpt=Xrq.Theadjustmentisthuscompleted. Useoftheprincipleofasteppedincreaseinthecontrolpointmakesitpossiblesynchronizethemovementsofthecylindersandsetthecontrolpointwithahighdegreeofaccuracyforalmostanyidealrepetitionfactor. MechanismsforIndividualAdjustmentoftheWorkingRollers.Theplate-straighteningmachineisdesignedsothateachworkingrollercanbemovedvertically,whichisdonebymeansofahydrauliccylinderactinginconcertwithaV-beltdrive.Thecylindersare
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