Control of Electromechanical Systems using Sliding Mode Techniques.docx

Contro1.ofE1.ectromechanica1.SystemsusingS1.idingModeTechniquesHeidcBrand1.S1.UdICrandMartinBussAbstractThisartic1.eproposesas1.idingmodecontro1.fore1.ectromechanica1.systems,forinstanceaDCmotorwithaninvertedpendu1.umas1.oadisconsidered.Incontrasttoconventiona1.cascadecontro1.structuresnoton1.ythevariab1.esofthemechanica1.systembuta1.so(hee1.ectrica1.variab1.esarcPar1.ofthecontro1.1.awandvo1.tageisusedasdiscontinuouscontro1.input.Thenewcontro1.approachoffersbetterperformance,nininia1.imp1.ementationcomp1.exity,providesrobustness,andadecreaseofpowerconsumption.Theer1.b11naceofthepresentedapproachisdemonstratedvianumerica1.simu1.ationsandarea1.experimcn1.I. INTRODUCTIONItiscommontodesigncontro1.formechanica1.systemswithtorqueorforceasthecontro1.action.Itisassumedthatthereexistsafastinnercontro1.kx)pprovidingadesiredcurrenti*.Therefore,forthespeedcontro1.1.erintheouter1.oopthecucntcontro1.1.oopistreatedasanidea1.currentsource,whichIneanSagivenreferencecurrenti*wi1.1.betrackedidea1.1.y.Anexamp1.eforsuchacontro1.schemei$showninfig.Ifora2ndordermechanica1.systemdrivenbyaDCmotor.Thereisa1.ow-1.eve1.feedback1.pusingapu1.sewidthmodu1.ated(PWM)signa1.or1.inearamp1.ifierprovidingthedesiredcurrentortorque.I1.iedesiredcurrentisgivenbythecontro1.1.awforthemechanica1.system.In>ro1.ppwm.DCMotor-tj(_CUrBntiedbac*1.oop!-0Fig.I.Conventiona1.cascadecontro1.structurefora2ndordermechanica1.systemdrivenbyaDCnrtor.Forhighperformancesystemsthereare1.imitsofthiscontro1.scheme.Thebandwidthoftheinnercontro1.1.oopis1.imited,becausethedesiredcurrenti*isanintegratedPWMsigna1.Hence,theperformanceoftheoutercontro1.1.oop,theperformanceofthemechanica1.system,is1.imitedbythisbandwidthofthecurrentcontro1.1.oop.Particu1.ar1.yduetoaverys1.ow1.ymovingmechanica1.system,positionsensordataarc1.imitedandthereforeasufficientestimationofthespeedsigna1.isnotpossib1.eandtheaccuratecontro1.ofthemechanica1.systemisrestricted.Anadditiona1.sensorforthee1.ectrica1.variab1.esofthesystemcou1.dofferbetterestimationofthenotmeasuredspeedvariab1.eofthemechanica1.system.IfaPWMsigna1.isused,currentcontro1.isbasedonanexact1.ydefinedswitchingfrequency.Inconsequence,independentofthecontro1.objectivethisextreme1.yhighswitchingfrequenceusingmaxima1.powerisa1.waysapp1.ied.Ifthemechanica1.variab1.esand'area1.sotakenintoaccountfordesignofcontro1.1.aw,re<1.ucionofenergycanbeachieved.Toovercometheabovedescribedprob1.ems,IhiSartic1.einvestigatesacontro1.schemefore1.ectromechanica1.systemsusingvo1.tageasthediscontinuouscontro1.input,dditiona1.tothemechanica1.variab1.es,thevariab1.eofthee1.ectrica1.system,thecurrent,in11uencesthecontro1.1.aw.S1.idingn>decontro1.ischosenbecauseitoi1.ersrobustnessaswe1.1.asfastdynamics.Furthermoreimp1.ementationofs1.idingmodecontro1.asfastswitchingcontro1.isa1.sopracticab1.e.Severa1.app1.icationsofs1.idingmodecontro1.ofDCmotors,inductionmotorsandsynchronousmotorshavebeenproposed,e.g.in1.1.ntheoutercontro1.1.oopof(hecontro1.schemeshowninfig.IPDorPIDcontro1.isusua1.1.yimp1.e11cnicd.Moreover,inordertoimproverobustness,trackingprob1.emsforpositionandangu1.arspeedofaDCmotora1.sohavebeenso1.vedbasedonas1.idingmodecontro1.approach(2J.Improvementofrobustnesbyaddings1.idinginodecontro1.ofmechanica1.systemforaninductionmotordrivewithforceddynamicshasbeenshown3.Neverthe1.ess,thisapproachsti1.1.isbasedonacascadecontro1.structureassumingfastidea1.1.ow-1.eve1.feedback1.oops.Thecontro1.schemeforane1.ectromechanica1.systemwhichisproposedinthisartic1.eusesadvantagesofs1.idinginodecontro1.andatthesametimechatteringeffectsaredecreasedbecausethevariab1.esofthee1.ectricdrivearepartofthecontro1.1.aw.Thee1.ectricmotoractsasfi1.terforhigh-frequencysigna1.s.Comparedtotheshowncascadecontro1.usings1.idingmodecontro1.structuresystemdynamicsbecomesfaster.Thesystemperformancei$characterizedbyinsensitivityoparametervariationsandrejectionofdisturbancesduetos1.idingmodecontro1.characteristicsaswe1.1.asminimia1.imp1.ementationcomp1.exityandreductionofenergy.Thisartic1.eana1.yzess1.idingmodecontro1.ofe1.ectromechanica1.systems.Insection11theproposedcontro1.schemeexp1.ainedforarbitrarye1.ectromechanica1.systemsreceivespriorityconsideration.Afterwardsitisdeve1.opedforasamp1.esystem,aninvertedpendu1.umdrivenbyaDCmotor.SectionIIIdiscussestheresu1.tsofnumerica1.simu1.ationsandtheexperimenta1.resu1.ts.Performanceoftheproposeds1.idingmodecontro1.iscomparedtothatofaconventiona1.contro1.method.II. DESCRIPTIONOFTHECONTRO1.A1.GORITHMIn(hi$artic1.enon1.inearn-<1.innsiona1.contro1.affinesystems.ifx+9,x)ux".u(I)arcconsidered.Fore1.ectromechanica1.systemsthesystemstateXconstistsofthestatevariab1.esofthee1.ectrica1.subsystemxe1.ectrandthevariab1.esofthemechanica1.subsystemxnech.Forthesystem(I)Iheideaoftheproposeds1.idingnx>decontro1.schemeisshowninfig.2.Incontrasttofig.Iforcontro1.designofthemechanica1.systemadditiona1.1.ytothemechanica1.dynamics,thedynamicsoftheDCmotorarctakenintoaccount.Fig. 2. Jkhcmaticdiagramofthep