Performance assessment using a normalized gradient

《Performance assessment using a normalized gradient》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、JournalofProcessControl16(2006)1013–1020www.elsevier.com/locate/jprocontPerformanceassessmentusinganormalizedgradientAriIngimundarson*EdificiTR11(CampusTerrassa),RambladeSantNebridi,10,TechnicalUniversityofCatalonia(UPC),08222Terrassa,SpainReceived4March2006;

2、receivedinrevisedform24July2006;accepted24July2006AbstractThepaperpresentsaperformanceassessmentmethodwhosepurposeistomakecontrollermaintenancebasedonadjustingthecon-trollergain,moresystematic.Anormalizedgradientofaquadraticcostfunctioniscalculatedwithregard

3、totheloopgain.Itisshownthatthisstatisticisveryeasytocalculateandthattheinformationcanbeusefultoimproveperformance.Calculationsofthegradientfortwoloopsfromapulpandpapermillthathadperformanceproblemsshowthevalidityofthemethodinanindustrialsetting.Ó2006Elsevier

4、Ltd.Allrightsreserved.Keywords:Controlperformanceassessment;PIDcontrol;Loopmanagement1.IntroductionThegradientgivesinformationaboutthespectralcontentofthedisturbancesaffectingtheloopcomparedtotheControllertuninghasbeenreportedasanimportantdesireddisturbancere

5、jectionbandwidth.Thisinformationcauseofbadcontrollerperformanceintheprocessindus-iscompressedintoonenumberbycalculatingthegradient.try,see[1].Theadventofacademicperformanceassess-Decisionstoadjusttheloopgaincanbemadewithmorementmethodshasnotimprovedmuchthats

6、ituation,seeinformationifthegradientisavailable.Themethodis[2].Itiscommonthatloopsareeithertunedtooaggres-notrestrictedtoPIDcontrollersbutas97%ofcontrollerssivelyandthustendtooscillate(30%ofloopsaccordingintheprocessindustryareofthattype,themethodispre-to[1]

7、)ortheyaredetunedsothattheresponseissluggish,sentedwiththatstructureinmind.see[3].LoopsmightbecommissionedinanappropriateThedesireddisturbancerejectionbandwidthismannerbutastheperformancedecayswithtimetheexpressedwiththedesiredcomplementarysensitivityfunc-1

8、importanceofeffectivemaintenanceisclear.tionoftheclosedloop,denotedTd(q).MosttuningrulesOneofthemorefrequentactsofmaintenanceofPIDeitherexplicitlyorimplicitlydependonamodelofthepro-controllersist