外文翻译--数控机床开环控制伺服系统与数控生产设备.doc -- 5 元

www.88doc88.comwww.yanziedu.com附录译文TheopensystemmeritofComputerNumericalControlandNumericalcontrolofproductionequipmentsAbstractTheopensystemmeritisthesystemsimple,thecostlow,buttheshortcomingistheprecisionislow.Thereversegap,theguidescrewpitcherror,stopinferiorlycanaffectthepointingaccuracybymistake.Followingseveralkindofimprovementsmeasuremaycausethepointingaccuracydistinctimprovement.Thekeywordnumericalcontrol、NC、theopensysterm1）reversegaperrorcompensatesThenumericalcontrolenginebedprocessingcuttingtoolandtheworkpiecerelativemotionisdependsuponthedriveimpetusgear,theguidescrewrotation,thustheimpetusworkfloorandsoonmovestheparttoproducemovesrealizes.Astraditionalpartgear,guidescrewalthoughthemanufactureprecisionisveryhigh,butalwaysunavoidablyhasthegap.Asaresultofthiskindofgapexistence,whenmovementdirectionchange,startsthesectiontimetobeabletocauseinevitablyactuatesthepartwastingtime,appearstheinstructionpulsetopushthemotionlessfunctionalelementtheaspect.Thishasaffectedtheenginebedprocessingprecision,namelytheinstructionpulseandactualentersforthestepdoesnottally,hastheprocessingerrortherefore,thesplitringnumericalcontrolsystemallestablishesgenerallyhasthereversegaperrorcompensatoryfunction,withbymakesupwhichwastestimethestepreversegapdifferencecompensatesisfirstactualreverseentersfortheerror,convertsthepulseequivalentnumberit,compensatesthesubroutineasthegaptheoutput,whenthecomputerjudgmentappearswheninstructionforcountermotion,transfersthegaptocompensatethesubroutineimmediately,compensatesthepulseaftertheoutputtoeliminatethereversegaptocarryonagainnormallyinsertsmakesupthemovement.2）oftenthevaluesystematiccharacteristicpositionerrorcompensatesAkindofstorehousebytransfersforthedesigner.Likethisinthecomponentsdesignstage,thedesigneronlymustinputthecharacteristictheparameter,thesystemdirectproductioncharacteristicexamplemodelWemustsavetherelatedcharacteristicclassinthedatabasethestructureinformation,thedatabasetablecollectionareuseinsavingthispartofrelatedinformation.Accordingwww.88doc88.comwww.yanziedu.comtothecharacteristictypedefinitionneed,wedefinedthecharacteristicclasscodetable,thecharacteristicclasseditioninformationhaveoutstandingshownthecharacteristictypeDefinedthecharacteristicclassstructureoutstandingtoreachthecharacteristicclassthestructureAndrelatesthroughthecomponentscharacteristicdispositiontableandthecomponentscharacteristiclevelinformation.Thecharacteristicleveldatasheetcollectionisthiscomponentsmodeldatabasedesigncore,hasrecordedcharacteristicexampleinformationandsoonmodeldesign,craft.ThecharacteristicstructuretablehasrecordedthecharacteristicgeometrystructureThecharacteristicsizetable,thecharacteristicshapepositiontableoflimits,thecharacteristicsurfaceroughnesstablehasrecordedthecharacteristicprojectsemanticsquotationThesizetable,theshapepositiontableoflimits,thesurfaceroughnesstablesavedallcomponentscharacteristicdatamessage.Inthecharacteristiclevel,usingcharacteristicID,geometryprincipallinkageandsoonessentialfactorID,sizeID,commondifferenceID,roughnessIDcarriesonthedataretrieval.WeapplythiscomponentsinformationmodeldatabaseunderthefactoryenvironmentsomemoduleCADintheAMintegrativesystem,hasrealizedCADandtheCAPPcharacteristicinformationsharingwell.MainusereadymadeCAD/theCAMsoftwareUnigra□phics1IcarriesontheproductdesignandtheNCprogramminginthissystem,andthroughcarriesontwotimesofdevelopmentsgainscomponentstothissoftwarethesizeinformationAtthesametimeusesthedialoguewindowwhichdevelopsvoluntarily,letsdesignthepersonneltoinputothercharacteristicinformationalternately,realizesthissoftwareandthesystemsharingdatabaseconnection.Whenassistancetechnologicaldesign,thetechnologicaldesignpersonnelthroughtheprocedureinquiryfunction,inquiresthecomponentsinformationfromthesharingdatabasewhichneeds,carriesontheinteractivetechnologicaldesign.ThushasfacilitatedtheCAPPcomponentsinformationacquisition,enhancedthetechnologicaldesignefficiency.WhencarriesontheNCprogrammingusingUG,mayfromthesharingdatabasegainthecraftandthemanufactureinformationwhichneeds,carriesonvariousworkingprocedurestheknifeaxledesignandtheprocessingsimulationestablishesanabsolutezerospotonthenumericalcontrolenginebed,theactualvariouscoordinateaxessyzygycompletelypositionerror,makesthecurveinordertodeterminedcompensatesthespot.Attemptsltoshowisanactualpositionerrorcurve,errorcarriesonthiscurveycoordinatetakethepulseequivalentastheunitthedivision,makesthehorizontalline,eachhorizontallineandthecurvepointofintersectionnamelycompensatesthespotforthegoal.Chart1thecenter1to6oclockplacepositionerrorsfor,needstodoreducesthepulsetocompensateButneedstocarryon6to9addsthepulsetocompensateinthecharttheshadowpartiallyfortocompensatethearea.CompensatestherangeofpointsthesetobecometheerrorThecalibrationcorrectionsstoresthecomputer,whenworktablebyzerodisplacementinposition,www.88doc88.comwww.yanziedu.cominstallssendsouttheabsolutezeropointlocalizationsignalintheabsolutezeropointmicroswitch,latercomputerasnecessarywillsendoutthegoaltocompensatetocompensatethesignal,willcarryonthepositionerrortotheenginebedtocompensate.Thecosinegeneratorassignsslideguageinitiationsignalaelectricityandbystepoftransmission.3）feedbackscompensatestheopenloopcontrolChart2hasproducedthiskindofsystemschematicdiagram.Thissystemsurveystwopartsbytheopenloopcontrolandtheinductionsynchromeshdirectpositiontobecomposed.Herepositionexaminationdoesnotserveasthepositionthefeedback,butiscompensatesthefeedbackasthepositionerror.ItscardinalprincipleisInstallstheinstructionpulsebytheenginebednumericalcontrolwhichCNCsendsout,ontheonehandthesuppliesopensystem,thecontrolstepbystepstheelectricalmachineryaccordingtotheinstructionrevolution,andthedirectdriveplatenmoves,constitutestheopenloopcontrolOntheotherhandthisinstructionpulsesuppliestheinductionsynchromeshthemeasurementsystemnamelydigitally,cosinegenerator,aspositiondemandsignalaby.Theworkinthewarningwayinductionsynchromeshthistimenotonlyisthepositionsensor,alsoisthecomparator,itby,Thecosinegeneratorassignsslideguageinitiationsignalaelectricityandbystepoftransmission.4）conclusionsUndertheCIMSenvironmentthetechnologywhichdevelopsunceasinglybasedoncharacteristiccomponentsinformationmodeling,howenhancesthecomponentsorderofcomplexitywhichthecharacteristicdesigncancompleteHowcausesquestionandsoonrequestwhichthecharacteristicdesignadoptiontrickrecognition,thecharacteristicsemanticstransformsalsotowaitforthepeopletosolve.Thisarticleintroducedthecharacteristictechnologyinthecomponentsinformationmodelingapplication,describesthiscomponentsdatamodeldatabaserealizationwithemphasisEstablishesthecomponentsinformationdatabasesystemmaysatisfytheCIMSsystemwelltotheletter.NumericalcontrolNCisaformofprogrammableautomationinwhichtheprocessingequipmentiscontrolledbymeansofnumbers,letters,andothersymbols.Thenumbers,letters,andsymbolsarecodedinanappropriateformattodefineaprogramofinstructionsforaparticularworkpartorjob.Whenthejobchanges,theprogramofinstructionsischanged.ThecapabilitytochangetheprogramiswhatmakesNCsuitableforlowandmediumvolumeproduction.Itismucheasiertowritenewprogramsthantomakemajoralterationsoftheprocessingequipment.BasiccomponentsofNCAnumericalcontrolsystemconsistsofthefollowingthreebasiccomponentsProgramofinstructionsMachinecontrolunitwww.88doc88.comwww.yanziedu.comProcessingequipmentThegeneralrelationshipamongthethreecomponentsisillustratedinFig.2.1.Theprogramisfedintothecontrolunit,whichdirectstheprocessingequipmentaccordingly.Theprogramofinstructionsisthedetailedstepbystepcommandsthatdirecttheprocessingequipment.Initsmostcommonform,thecommandsrefertopositionsofamachinetoolspindlewithrespecttotheworktableonwhichthepartisfixtured.Moreadvancedinstructionsincludeselectionofspindlespeeds,cuttingtool,andotherfunction.Themostcommonmediuminuseoverthelastseveraldecadeshasbeen1in.widepunchedtape.Becauseofthewidespreaduseofthepunchedtape,NCissometimescalledtapecontrol.However,thisisamisnomerinmodernusageofnumericalcontrol.Comingintousemorerecentlyhavebeenmagnetictapecassettesandfloppydiskettes.ThemachinecontrolunitMCUconsistsoftheelectronicsandcontrolhardwarethatreadandinterprettheprogramofinstructionandconvertitintomechanicalactionsofthemachinetoolorotherprocessingequipment.TheprocessingequipmentisthethirdbasiccomponentofanNCsystem.Itisthecomponentthatperformsusefulwork.Inthemostcommonexampleofnumericalcontrol,onethatperformsmachiningoperations,theprocessingequipmentconsistsoftheworktableandspindleaswellasthemotorsandcontrolsneededtodrivethem.TYPESOFCONTROLSYSTEMSTherearetwobasictypesofcontrolsystemsinnumericalcontrolpointtopointandcontouring.Inthepointtopointsystem,alsocalledpositioning,eachaxisofthemachineisdrivenseparatelybyleadscrewsand,dependingonthetypeofoperation,atdifferentvelocities.Themachinemovesinitiallyatmaximumvelocityinordertoreducenonproductivetimebutdeceleratesasthetoolreachesitsnumericallydefinedposition.Thusinanpotationsuchasdrillingorpunching,thepositioningandcuttingtakeplacesequentially.Aftertheholeisdrilledorpunched,thetoolretracts,movesrapidlytoanotherposition,andrepeatstheoperation.ThepathfollowedfromonepositiontoanotherisimportantinonlyonerespectThetimerequiredshouldbeminimizedforefficiency.Pointtopointsystemsareusedmainlyindrilling,punching,andstraightmillingoperations.Inthecontouringsystem,alsoknownasthecontinuouspathsystem,positioningandcuttingoperationsarebothalongcontrolledpathsbutatdifferentvelocities.Becausethetoolcutsasittravelsalongaprescribedpath,accuratecontrolandsynchronizationofvelocitiesandmovementsareimportant.Thecontouringsystemisusedonlathes,millingmachines,grinders,weldingmachinery,andmachiningcenters.