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-/外文文献：KnowledgeofthesteppermotorWhatisasteppermotor：Steppermotorisakindofelectricalpulsesintoangulardisplacementoftheimplementingagency.Popularlittlelesson:Whenthedriverreceivesasteppulsesignal,itwilldriveasteppermotortosetthedirectionofrotationatafixedangle(andthestepangle).Youcancontrolthenumberofpulsestocontroltheangulardisplacement,soastoachieveaccuratepositioningpurposes;thesametimeyoucancontrolthepulsefrequencytocontrolthemotorrotationspeedandacceleration,toachievespeedcontrolpurposes.Whatkindsofsteppermotorsub-：Inthreesteppermotors:permanentmagnet(PM),reactive(VR)andhybrid(HB)permanentmagnetstepperusuallytwo-phase,torque,andsmaller,stepangleof7.5degreesorthegeneral15degrees;reactionstepisgenerallythree-phase,canachievehightorqueoutput,stepangleof1.5degreesisgenerally,butthenoiseandvibrationarelarge.80countriesinEuropeandAmericahavebeeneliminated;hybridstepperisamixofpermanentmagnetandreactiveadvantages.Itconsistsoftwophasesandthefive-phase:two-phasestepangleof1.8degreeswhilethegeneralfive-phasestepangleof0.72degreesgenerally.ThemostwidelyusedStepperMotor.Whatistokeepthetorque(HOLDINGTORQUE)Howmuchprecisionsteppermotor?Whetherthecumulative：Thegeneralaccuracyofthesteppermotorstepangleof3-5%,andnotcumulative.-/SteppermotortoallowtheminimumamountofsurfacetemperatureSteppermotortoallowtheminimumamountofsurfacetemperature：Steppermotorcausesthemotortemperatureistoohighthefirstmagneticdemagnetization,resultinginlossoftorquedownevenfurther,sothemotorsurfacetemperatureshouldbethemaximumalloweddependingonthemotordemagnetizationofmagneticmaterialpoints;Generallyspeaking,themagneticdemagnetizationpointsareabove130degreesCelsius,andsomeevenashighas200degreesCelsius,sothesteppermotorsurfacetemperatureof80-90degreesCelsiusisnormal.HowtodeterminethesteppermotordriverDCpowersupply：A.DeterminationofthevoltageHybridsteppingmotordriverpowersupplyvoltageisgenerallyawiderange(suchastheIM483supplyvoltageof12~48VDC),thesupplyvoltageisusuallybasedontheworkofthemotorspeedandresponsetotherequesttochoose.Ifthemotoroperatingspeedhigherorfasterresponsetotherequest,thenthevoltagevalueishigh,butnotethattheripplevoltagecannotexceedthemaximuminputvoltageofthedrive,oritmaydamagethedrive.B.DeterminationofCurrentPowersupplycurrentisgenerallybasedontheoutputphasecurrentdriveItodetermine.Ifalinearpowersupply,powersupplycurrentisgenerallypreferable1.1to1.3timestheI;ifweadopttheswitchingpowersupply,powersupplycurrentisgenerallypreferabletoI,1.5to2.0times.Themaincharacteristicsofsteppingmotor：Asteppermotordrivecanbeaddedoperatepulsedrivesignalmustbeno-/pulsewhenthesteppermotoratrest,suchasIfaddingtheappropriatepulsesignal,itwilltoacertainangle(calledthestepangle)rotation.Rotationspeedandpulsefrequencyisproportionalto.2Dragonstepanglesteppermotorversionis7.5degrees,360degreesaround,takes48pulsestocomplete.3steppermotorhasinstantstartandrapidcessationofsuperiorcharacteristics.Changethepulseoftheorderof4,youcaneasilychangethedirectionofrotation.Therefore,thecurrentprinters,plotters,robotics,andsodevicesarethecoreofthesteppermotorasthedrivingforce.SteppermotorcontrolexampleWeusefour-phaseunipolarsteppermotorasanexample.ThestructureshowninFigure1:Fourfour-phasewindingleads(asopposedtophaseA1A2B1phasephaseB2)andtwopubliclines(tothepowerofpositive).Thewindingsofonephasetothepoweroftheground.Sothatthewindingswillbeinspired.Weusefour-phaseeight-beatcontrol,ie,1phase2phasealternatingturn,wouldenhanceresolution.0.9°perstepcanbetransferredtocontrolthemotorexcitationistransferredinorderasfollows:Iftherequirementsofmotorreversal,thetransmissionexcitationsignalcanbereversed.2controlschemeControlsystemblockdiagramisasfollowsTheprogramusesAT89S51asthemaincontroldevice.Itiscompatiblewith-/theAT89C51,butalsoincreasedtheSPIinterfaceandthewatchdogmodule,whichnotonlymakesthedebuggingprocessbecomeseasyandalsomorestable.Themicrocontrollerintheprogrammainlyforfieldsignalacquisitionandoperationofthesteppermotortocalculatethedirectionandspeedinformation.ThensenttotheCPLD.CPLDwithEPM7128SLC84-15,EPM7128programmablelogicdeviceoflarge-scale,fortheALTERAcompany'sMAX7000family.Highimpedance,electricallyerasableandothercharacteristics,canbeusedforthe2500unit,theworkingvoltageof+5V.CPLDreceivesinformationsentfromthemicrocontrollerafterconvertedtothecorrespondingcontrolsignaloutputtothesteppermotordrive.Putthecontrolsignaldrivesthemotorwindingsaftertheinput,toachieveeffectivecontrolofthemotor.2.1ThehardwarestructureofthemotordriveMotordriveusingthefollowingcircuit:R1-R8inwhichtheresistancevalueof320Ω.R9-R12resistancevalue2.2KΩ.Q1-Q4asDarlingtonD401A,Q5-Q8fortheS8550.J1,J2andthesteppermotorconnectedtothesix-lead。AdvantagesanddisadvantagesofsteppermotorAdvantages1.Themotorrotationangleisproportionaltothenumberofpulses;2.Whenthemotorstoppedwithamaximumtorque(whenthewindingexcitationtime);3.Sincetheaccuracyofeachstepinthethreepercenttofivepercent,andtheerrorwillnotaccumulatetothenextstepandthushasbetterpositional-/accuracyandrepeatabilityofmovement;4.Excellentresponsefromthestopa