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2025-07-16 19:00 本頁面
【文章內(nèi)容簡介】 freality,sincemodelingerrorsareinevitable.Moreover,onecanuseasimplifiedmodelonpurpose.Inthispaper,thestructuredandunstructureduncertaintiesareofprimaryinterest,.,themodelingerrorduetotheparametersvariationandunmodeledmodes,especiallythefrictionandsensordynamics,neglectedtimedelays,Theerroneousmodelandthedemandforhighperformancerequirethecontrollertoberobust.Theslidingmodecontrollers(SMC)basedonvariablestructurecontrolcanbeusediftheinaccuraciesinthemodelstructureareboundedwithknownbounds.However,anSMChassomedisadvantages,relatedtochatteringofthecontrolinputsignal.Oftenthisphenomenonisundesirable,sinceitcausesexcessivecontrolactionleadingtoincreasewearoftheactuatorsandtoexcitationofunmodeleddynamics.Theattemptstoattenuatethisundesirableeffectresultinthedeteriorationoftherobustnesscharacteristics.Thisisawellknownproblemandwidelytreatedintheliterature.Inordertoobtainsmoothinginthebangbangtypeddiscontinuitiesoftheslidingmodecontrollerdifferentschemeshavebeensuggested.AnotherimportantissuelimitingthepracticalapplicabilityofSMCistheoverconservativecontrollawduetotheupperboundsoftheuncertainties.Inpracticemostoftentheworstcaseimplementedincontrollawdoesnottakeplaceandtheresultinglargecontrolinputsbeeunnecessaryanduneconomical.Inthispaperwesuggestanapproachtothedesignofdecentralizedmotioncontrollersforelectromechanicalsystemsbesidestheslidingmodemotioncontrollerstructureanddisturbancetorqueestimation.Theaccuracyoftheestimationisthecriticalparameterforrobustnessinthisscheme,asopposedtotheupperboundsoftheperturbationsthemselves.Consequently,thedrivingtermsoftheerrordynamicsarereducedfromtheuncertainties(asintheconventionalSMC)totheaccuracyintheirestimates.Theresultisamuchbettertrackingaccuracywithoutbeingoverconservativeincontrol.Experimentalrobustnesspropertiesoffuzzycontrollersremaintheoreticallydifficulttoproveandtheirsynthesisisstillanopenproblem.Thenonlinearstructureofthefinalcontrollerisderivedfromallcontrollersatthedifferentstagesoffuzzycontrol,particularlyfrommondefuzzificationmethods(suchasCentreofArea).Ingeneral,fuzzycontrollershavearegionwisestructuregiventhepartitionofitsinputspacebythefuzzificationstage.Localcontrolsdesignedintheseregionsarethenbinedintosetstomakeupthefinalglobalcontrol.Apartitionofthestatespacecanbefoundforwhichthecontrollerhasregionwiseconstantparameters.Moreover,eachfuzzycontrollertuningparameter(.theshapesandthevaluesofinputoroutputvariablesmembershipfunctions)influencesthevaluesofparametersinseveralregionsatthesametime.Intheparticularcaseofaswitchinglineseparatingthephaseplaneintooneregionwherethecontrolispositivewhereasintheotheritisnegative,thefuzzycontrollermaybeseenasavariablestructurecontroller.Thiskindofafuzzycontrollercanbeassimilatedtoavariab
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