文献翻译数控机床开环控制伺服系统与数控生产设备.docx
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文献翻译数控机床开环控制伺服系统与数控生产设备
附录
译文:
TheopensystemmeritofComputerNumericalControlandNumericalcontrolofproductionequipments
Abstract
Theopensystemmeritisthesystemsimple,thecostlow,buttheshortcomingistheprecisionislow.Thereversegap,theguidescrewpitcherror,stopinferiorlycanaffectthepointingaccuracybymistake.Followingseveralkindofimprovementsmeasuremaycausethepointingaccuracydistinctimprovement.
Thekeyword:
numericalcontrol、NC、theopensysterm
1)reversegaperrorcompensates
Thenumericalcontrolenginebedprocessingcuttingtoolandtheworkpiecerelativemotionisdependsuponthedriveimpetusgear,theguidescrewrotation,thustheimpetusworkfloorandsoonmovestheparttoproducemovesrealizes.Astraditionalpartgear,guidescrewalthoughthemanufactureprecisionisveryhigh,butalwaysunavoidablyhasthegap.Asaresultofthiskindofgapexistence,whenmovementdirectionchange,startsthesectiontimetobeableto
causeinevitablyactuatesthepartwastingtime,appearstheinstructionpulsetopushthemotionlessfunctionalelementtheaspect.Thishasaffectedtheenginebedprocessingprecision,namelytheinstructionpulseandactualentersforthestepdoesnottally,hastheprocessingerrortherefore,thesplit-ringnumericalcontrolsystemallestablishesgenerallyhasthereversegaperror
compensatoryfunction,withbymakesupwhichwastestimethestepreversegapdifferencecompensatesisfirstactualreverseentersfortheerror,convertsthepulseequivalentnumberit,compensatesthesubroutineasthegaptheoutput,whenthecomputerjudgmentappears
wheninstructionforcountermotion,transfersthegaptocompensatethesubroutineimmediately,compensatesthepulseaftertheoutputtoeliminatethereversegaptocarryonagainnormallyinsertsmakesupthemovement.
2)oftenthevaluesystematiccharacteristicpositionerrorcompensates
Akindofstorehousebytransfersforthedesigner.Likethisinthecomponentsdesignstage,thedesigneronlymustinputthecharacteristictheparameter,thesystemdirectproduction
characteristicexamplemodel:
Wemustsavetherelatedcharacteristicclassinthedatabasethestructureinformation,thedatabasetablecollectionareuseinsavingthispartofrelatedinformation.Accordingtothecharacteristictypedefinitionneed,wedefinedthecharacteristicclasscodetable,thecharacteristicclasseditioninformationhaveoutstandingshownthecharacteristictype;Definedthecharacteristicclassstructureoutstandingtoreachthecharacteristicclassthestructure;Andrelatesthroughthecomponentscharacteristicdispositiontableandthecomponentscharacteristiclevelinformation.Thecharacteristicleveldatasheetcollectionis
thiscomponentsmodeldatabasedesigncore,hasrecordedcharacteristicexampleinformationandsoonmodeldesign,craft.Thecharacteristicstructuretablehasrecordedthecharacteristic
geometrystructure;Thecharacteristicsizetable,thecharacteristicshapepositiontableoflimits,thecharacteristicsurfaceroughnesstablehasrecordedthecharacteristicprojectsemanticsquotation;Thesizetable,theshapepositiontableoflimits,thesurfaceroughness
tablesavedallcomponentscharacteristicdatamessage.Inthecharacteristiclevel,usingcharacteristicID,geometryprincipallinkageandsoonessentialfactorID,sizeID,commondifferenceID,roughnessIDcarriesonthedataretrieval.WeapplythiscomponentsinformationmodeldatabaseunderthefactoryenvironmentsomemoduleCADintheAMintegrativesystem,hasrealizedCADandtheCAPPcharacteristicinformationsharingwell.Mainuseready-madeCAD/theCAMsoftware(Unigra□phics1I)carriesontheproductdesignandtheNCprogramminginthissystem,andthroughcarriesontwotimesofdevelopmentsgainscomponentstothissoftwarethesizeinformation;Atthesametimeusesthedialoguewindowwhichdevelopsvoluntarily,letsdesignthepersonneltoinputothercharacteristicinformationalternately,realizesthissoftwareandthesystemsharingdatabaseconnection.Whenassistancetechnologicaldesign,thetechnologicaldesignpersonnelthroughtheprocedureinquiryfunction,inquiresthecomponentsinformationfromthesharingdatabasewhichneeds,carriesontheinteractivetechnologicaldesign.ThushasfacilitatedtheCAPPcomponentsinformationacquisition,enhancedthetechnologicaldesignefficiency.WhencarriesontheNCprogrammingusingUG,mayfromthesharingdatabasegainthecraftandthemanufactureinformationwhichneeds,carriesonvariousworkingprocedurestheknifeaxledesignandtheprocessingsimulationestablishesanabsolutezerospotonthenumericalcontrolenginebed,theactualvariouscoordinateaxessyzygycompletelypositionerror,makesthecurveinordertodeterminedcompensatesthespot.Attemptsltoshowisanactualpositionerrorcurve,(error)carriesonthiscurvey-coordinatetakethepulseequivalentastheunitthedivision,makesthehorizontalline,eachhorizontallineandthecurvepointofintersectionnamelycompensatesthespotforthegoal.Chart1thecenter1to6o'clockplacepositionerrorsfor,needstodoreducesthepulsetocompensate;Butneedstocarryon6to9addsthepulsetocompensateinthecharttheshadowpartiallyfortocompensatethearea.Compensatestherangeofpointsthesetobecometheerror
Thecalibrationcorrectionsstoresthecomputer,whenworktablebyzerodisplacementinposition,installssendsouttheabsolutezeropointlocalizationsignalintheabsolutezeropointmicroswitch,latercomputerasnecessarywillsendoutthegoaltocompensatetocompensatethesignal,willcarryonthepositionerrortotheenginebedtocompensate.Thecosinegeneratorassignsslideguageinitiationsignalaelectricityandbystepoftransmission.
3)feedbackscompensatestheopen-loopcontrol
Chart2hasproducedthiskindofsystemschematicdiagram.Thissystemsurveystwopartsbytheopen-loopcontrolandtheinductionsynchromeshdirectpositiontobecomposed.Herepositionexaminationdoesnotserveasthepositionthefeedback,butiscompensatesthefeedbackasthepositionerror.Itscardinalprincipleis:
InstallstheinstructionpulsebytheenginebednumericalcontrolwhichCNCsendsout,ontheonehandthesuppliesopensystem,the
controlstep-by-stepstheelectricalmachineryaccordingtotheinstructionrevolution,andthedirectdriveplatenmoves,constitutestheopen-loopcontrol;Ontheotherhandthisinstructionpulsesuppliestheinductionsynchromeshthemeasurementsystem(namelydigitally,cosinegenerator),aspositiondemandsignalaby.Theworkinthewarningwayinductionsynchromeshthistimenotonlyisthepositionsensor,alsoisthecomparator,itby,Thecosinegeneratorassignsslideguageinitiationsignalaelectricityandbystepoftransmission.
4)conclusions
UndertheCIMSenvironmentthetechnologywhichdevelopsunceasinglybasedoncharacteristiccomponentsinformationmodeling,howenhancesthecomponentsorderofcomplexitywhichthecharacteristicdesigncancomplete;Howcausesquestionandsoonrequestwhichthecharacteristicdesignadoptiontrickrecognition,thecharacteristicsemanticstransformsalsotowaitforthepeopletosolve.Thisarticleintroducedthecharacteristictechnologyinthecomponentsinformationmodelingapplication,describesthiscomponentsdatamodeldatabaserealizationwithemphasis;EstablishesthecomponentsinformationdatabasesystemmaysatisfytheCIMSsystemwelltotheletter.
Numericalcontrol(NC)isaformofprogrammableautomationinwhichtheprocessingequipmentiscontrolledbymeansofnumbers,letters,andothersymbols.Thenumbers,letters,andsymbolsarecodedinanappropriateformattodefineaprogramofinstructionsforaparticularworkpartorjob.Whenthejobchanges,theprogramofinstructionsischanged.ThecapabilitytochangetheprogramiswhatmakesNCsuitableforlow-andmedium-volumeproduction.Itismucheasiertowritenewprogramsthantomakemajoralterationsoftheprocessingequipment.
BasiccomponentsofNC
Anumericalcontrolsystemconsistsofthefollowingthreebasiccomponents:
·Programofinstructions
·Machinecontrolunit
·Processingequipment
ThegeneralrelationshipamongthethreecomponentsisillustratedinFig.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.
TYPESOFCONTROLSYSTEMS
Therearetwobasictypesofcontrolsystemsi