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ID:37664827
大小:978.34 KB
页数:9页
时间:2019-05-28
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1、CycletoCycleManufacturingProcessControlDavidE.Hardt*andTsz-Sin-Siu*Abstract--Mostmanufacturingprocessesproduceparts·Highbandwidthcontrolofmachinestatevariablessuchthatcanonlybecorrectlymeasuredaftertheprocesscyclehasasdisplacement,force,pressureortemperature.(ma-beencompl
2、eted.Evenifin-processmeasurementandcontrolchinestatecontrol)ispossible,itisoftentooexpensiveorcomplextopractically·Outputsamplingwithprocessdiagnosticsbasedonimplement.Inthispaper,asimplecontrolschemebasedonmeasuredprocessstatistics.StatisticalProcessControloutputmeasurem
3、entandinputchangeaftereachprocessing(SPC)cycleisproposed.Itisshowntoreducetheprocessdynamicstoasimplegainwithadelay,andreducethecontrolproblemExamplesofintermediatelevelsofcontrolsuchastoaSISOdiscretetimeproblem.Thegoalofthecontrolleristobothreducemeanoutputerrorsandreduc
4、etheirvariance.materialstatecontrol(e.g.directfeedbackofmaterialInsodoingtheprocesscapability(e.g.Cpk)canbeincreasedstress,strainortemperature)areveryunusual.Evenlesswithoutadditionalinvestmentincontrolhardwareorin-commonareexamplesofdirectprocessoutputfeedback,processsen
5、sors.Thiscontrolsystemisanalyzedfortwotypessuchasin-processpartgeometryfeedback.ofdisturbanceprocesses:independent(uncorrelated)andde-Asimpleblockdiagramofaprocess(seeFig.1)em-pendent(correlated).Fortheformertheclosed-loopcontrolphasizesthesedistinctions.Italsoshowsclearl
6、ythatanyincreasedtheoutputvariance,whereasforthelatteritcancontrolotherthanoutputfeedbackneglectstheinfluenceofdecreaseitsignificantly.Inbothcases,propercontrollerde-ubiquitousprocessdisturbances.Themostcommonofsigncanreducethemeanerrortozerowithoutintroducingtheseisthehi
7、ghlikelihoodofmaterialpropertyvariations.poortransientperformance.Thesefindingweredemon-stratedbyimplementingCycletoCycle(CtC)controlonasimplebendingprocess(uncorrelateddisturbance)andonanCONTR.EQUIPMENTMATERIALinjectionmoldingprocess(correlateddisturbance).There-sultsfol
8、lowedcloselythosepredictedbytheanalysis.EquipmentloopIndexTerms--ManufacturingProcessControl,SPC
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