外文翻译--数控机床开环控制伺服系统与数控生产设备.doc
www.88doc88.comwww.yanziedu.com附录译文:TheopensystemmeritofComputerNumericalControlandNumericalcontrolofproductionequipmentsAbstractTheopensystemmeritisthesystemsimple,thecostlow,buttheshortcomingistheprecisionislow.Thereversegap,theguidescrewpitcherror,stopinferiorlycanaffectthepointingaccuracybymistake.Followingseveralkindofimprovementsmeasuremaycausethepointingaccuracydistinctimprovement.Thekeyword:numericalcontrol、NC、theopensysterm1)reversegaperrorcompensatesThenumericalcontrolenginebedprocessingcuttingtoolandtheworkpiecerelativemotionisdependsuponthedriveimpetusgear,theguidescrewrotation,thustheimpetusworkfloorandsoonmovestheparttoproducemovesrealizes.Astraditionalpartgear,guidescrewalthoughthemanufactureprecisionisveryhigh,butalwaysunavoidablyhasthegap.Asaresultofthiskindofgapexistence,whenmovementdirectionchange,startsthesectiontimetobeabletocauseinevitablyactuatesthepartwastingtime,appearstheinstructionpulsetopushthemotionlessfunctionalelementtheaspect.Thishasaffectedtheenginebedprocessingprecision,namelytheinstructionpulseandactualentersforthestepdoesnottally,hastheprocessingerrortherefore,thesplit-ringnumericalcontrolsystemallestablishesgenerallyhasthereversegaperrorcompensatoryfunction,withbymakesupwhichwastestimethestepreversegapdifferencecompensatesisfirstactualreverseentersfortheerror,convertsthepulseequivalentnumberit,compensatesthesubroutineasthegaptheoutput,whenthecomputerjudgmentappearswheninstructionforcountermotion,transfersthegaptocompensatethesubroutineimmediately,compensatesthepulseaftertheoutputtoeliminatethereversegaptocarryonagainnormallyinsertsmakesupthemovement.2)oftenthevaluesystematiccharacteristicpositionerrorcompensatesAkindofstorehousebytransfersforthedesigner.Likethisinthecomponentsdesignstage,thedesigneronlymustinputthecharacteristictheparameter,thesystemdirectproductioncharacteristicexamplemodel:Wemustsavetherelatedcharacteristicclassinthedatabasethestructureinformation,thedatabasetablecollectionareuseinsavingthispartofrelatedinformation.Accordingwww.88doc88.comwww.yanziedu.comtothecharacteristictypedefinitionneed,wedefinedthecharacteristicclasscodetable,thecharacteristicclasseditioninformationhaveoutstandingshownthecharacteristictype;Definedthecharacteristicclassstructureoutstandingtoreachthecharacteristicclassthestructure;Andrelatesthroughthecomponentscharacteristicdispositiontableandthecomponentscharacteristiclevelinformation.Thecharacteristicleveldatasheetcollectionisthiscomponentsmodeldatabasedesigncore,hasrecordedcharacteristicexampleinformationandsoonmodeldesign,craft.Thecharacteristicstructuretablehasrecordedthecharacteristicgeometrystructure;Thecharacteristicsizetable,thecharacteristicshapepositiontableoflimits,thecharacteristicsurfaceroughnesstablehasrecordedthecharacteristicprojectsemanticsquotation;Thesizetable,theshapepositiontableoflimits,thesurfaceroughnesstablesavedallcomponentscharacteristicdatamessage.Inthecharacteristiclevel,usingcharacteristicID,geometryprincipallinkageandsoonessentialfactorID,sizeID,commondifferenceID,roughnessIDcarriesonthedataretrieval.WeapplythiscomponentsinformationmodeldatabaseunderthefactoryenvironmentsomemoduleCADintheAMintegrativesystem,hasrealizedCADandtheCAPPcharacteristicinformationsharingwell.Mainuseready-madeCAD/theCAMsoftware(Unigraphics1I)carriesontheproductdesignandtheNCprogramminginthissystem,andthroughcarriesontwotimesofdevelopmentsgainscomponentstothissoftwarethesizeinformation;Atthesametimeusesthedialoguewindowwhichdevelopsvoluntarily,letsdesignthepersonneltoinputothercharacteristicinformationalternately,realizesthissoftwareandthesystemsharingdatabaseconnection.Whenassistancetechnologicaldesign,thetechnologicaldesignpersonnelthroughtheprocedureinquiryfunction,inquiresthecomponentsinformationfromthesharingdatabasewhichneeds,carriesontheinteractivetechnologicaldesign.ThushasfacilitatedtheCAPPcomponentsinformationacquisition,enhancedthetechnologicaldesignefficiency.WhencarriesontheNCprogrammingusingUG,mayfromthesharingdatabasegainthecraftandthemanufactureinformationwhichneeds,carriesonvariousworkingprocedurestheknifeaxledesignandtheprocessingsimulationestablishesanabsolutezerospotonthenumericalcontrolenginebed,theactualvariouscoordinateaxessyzygycompletelypositionerror,makesthecurveinordertodeterminedcompensatesthespot.Attemptsltoshowisanactualpositionerrorcurve,(error)carriesonthiscurvey-coordinatetakethepulseequivalentastheunitthedivision,makesthehorizontalline,eachhorizontallineandthecurvepointofintersectionnamelycompensatesthespotforthegoal.Chart1thecenter1to6oclockplacepositionerrorsfor,needstodoreducesthepulsetocompensate;Butneedstocarryon6to9addsthepulsetocompensateinthecharttheshadowpartiallyfortocompensatethearea.CompensatestherangeofpointsthesetobecometheerrorThecalibrationcorrectionsstoresthecomputer,whenworktablebyzerodisplacementinposition,www.88doc88.comwww.yanziedu.cominstallssendsouttheabsolutezeropointlocalizationsignalintheabsolutezeropointmicroswitch,latercomputerasnecessarywillsendoutthegoaltocompensatetocompensatethesignal,willcarryonthepositionerrortotheenginebedtocompensate.Thecosinegeneratorassignsslideguageinitiationsignalaelectricityandbystepoftransmission.3)feedbackscompensatestheopen-loopcontrolChart2hasproducedthiskindofsystemschematicdiagram.Thissystemsurveystwopartsbytheopen-loopcontrolandtheinductionsynchromeshdirectpositiontobecomposed.Herepositionexaminationdoesnotserveasthepositionthefeedback,butiscompensatesthefeedbackasthepositionerror.Itscardinalprincipleis:InstallstheinstructionpulsebytheenginebednumericalcontrolwhichCNCsendsout,ontheonehandthesuppliesopensystem,thecontrolstep-by-stepstheelectricalmachineryaccordingtotheinstructionrevolution,andthedirectdriveplatenmoves,constitutestheopen-loopcontrol;Ontheotherhandthisinstructionpulsesuppliestheinductionsynchromeshthemeasurementsystem(namelydigitally,cosinegenerator),aspositiondemandsignalaby.Theworkinthewarningwayinductionsynchromeshthistimenotonlyisthepositionsensor,alsoisthecomparator,itby,Thecosinegeneratorassignsslideguageinitiationsignalaelectricityandbystepoftransmission.4)conclusionsUndertheCIMSenvironmentthetechnologywhichdevelopsunceasinglybasedoncharacteristiccomponentsinformationmodeling,howenhancesthecomponentsorderofcomplexitywhichthecharacteristicdesigncancomplete;Howcausesquestionandsoonrequestwhichthecharacteristicdesignadoptiontrickrecognition,thecharacteristicsemanticstransformsalsotowaitforthepeopletosolve.Thisarticleintroducedthecharacteristictechnologyinthecomponentsinformationmodelingapplication,describesthiscomponentsdatamodeldatabaserealizationwithemphasis;EstablishesthecomponentsinformationdatabasesystemmaysatisfytheCIMSsystemwelltotheletter.Numericalcontrol(NC)isaformofprogrammableautomationinwhichtheprocessingequipmentiscontrolledbymeansofnumbers,letters,andothersymbols.Thenumbers,letters,andsymbolsarecodedinanappropriateformattodefineaprogramofinstructionsforaparticularworkpartorjob.Whenthejobchanges,theprogramofinstructionsischanged.ThecapabilitytochangetheprogramiswhatmakesNCsuitableforlow-andmedium-volumeproduction.Itismucheasiertowritenewprogramsthantomakemajoralterationsoftheprocessingequipment.BasiccomponentsofNCAnumericalcontrolsystemconsistsofthefollowingthreebasiccomponents:·Programofinstructions·Machinecontrolunitwww.88doc88.comwww.yanziedu.com·ProcessingequipmentThegeneralrelationshipamongthethreecomponentsisillustratedinFig.2.1.Theprogramisfedintothecontrolunit,whichdirectstheprocessingequipmentaccordingly.Theprogramofinstructionsisthedetailedstep-by-stepcommandsthatdirecttheprocessingequipment.Initsmostcommonform,thecommandsrefertopositionsofamachinetoolspindlewithrespecttotheworktableonwhichthepartisfixtured.Moreadvancedinstructionsincludeselectionofspindlespeeds,cuttingtool,andotherfunction.Themostcommonmediuminuseoverthelastseveraldecadeshasbeen1-in.-widepunchedtape.Becauseofthewidespreaduseofthepunchedtape,NCissometimescalled“tapecontrol”.However,thisisamisnomerinmodernusageofnumericalcontrol.Comingintousemorerecentlyhavebeenmagnetictapecassettesandfloppydiskettes.Themachinecontrolunit(MCU)consistsoftheelectronicsandcontrolhardwarethatreadandinterprettheprogramofinstructionandconvertitintomechanicalactionsofthemachinetoolorotherprocessingequipment.TheprocessingequipmentisthethirdbasiccomponentofanNCsystem.Itisthecomponentthatperformsusefulwork.Inthemostcommonexampleofnumericalcontrol,onethatperformsmachiningoperations,theprocessingequipmentconsistsoftheworktableandspindleaswellasthemotorsandcontrolsneededtodrivethem.TYPESOFCONTROLSYSTEMSTherearetwobasictypesofcontrolsystemsinnumericalcontrol:point-to-pointandcontouring.Inthepoint-to-pointsystem,alsocalledpositioning,eachaxisofthemachineisdrivenseparatelybyleadscrewsand,dependingonthetypeofoperation,atdifferentvelocities.Themachinemovesinitiallyatmaximumvelocityinordertoreducenonproductivetimebutdeceleratesasthetoolreachesitsnumericallydefinedposition.Thusinanpotationsuchasdrillingorpunching,thepositioningandcuttingtakeplacesequentially.Aftertheholeisdrilledorpunched,thetoolretracts,movesrapidlytoanotherposition,andrepeatstheoperation.Thepathfollowedfromonepositiontoanotherisimportantinonlyonerespect:Thetimerequiredshouldbeminimizedforefficiency.Point-to-pointsystemsareusedmainlyindrilling,punching,andstraightmillingoperations.Inthecontouringsystem,alsoknownasthecontinuouspathsystem,positioningandcuttingoperationsarebothalongcontrolledpathsbutatdifferentvelocities.Becausethetoolcutsasittravelsalongaprescribedpath,accuratecontrolandsynchronizationofvelocitiesandmovementsareimportant.Thecontouringsystemisusedonlathes,millingmachines,grinders,weldingmachinery,andmachiningcenters.