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1、matlab白瞳ThisexampleshowsthecomparisonofthreeDCmotorcontroltechniquesfortrackingsetpointcommandsandreducingsensitivitytoloaddisturbances:§feedforwardcommand§integralfeedbackcontrol§LQRregulationSee"GettingStarted:BuildingModels"formoredetailsabouttheDCmotormod
2、el.ContentsProblemStatementInarmature-controlledDCmotors,theappliedvoltageVacontrolstheangularvelocitywoftheshaft.ThisexampleshowstwoDCmotorcontroltechniquesforreducingthesensitivityofwtoloadvariations(changesinthetorqueopposedbythemotorload).Asimplifiedmodel
3、oftheDCmotorisshownabove.ThetorqueTdmodelsloaddisturbances.Youmustminimizethespeedvariationsinducedbysuchdisturbances.Forthisexample,thephysicalconstantsare:R=2.0;%OhmsL=0.5;%HenrysKm=0.1;%torqueconstantKb=0.1;%backemfconstantKf=0.2;%NmsJ=0.02;%kg.m^2/s^2Firs
4、tconstructastate-spacemodeloftheDCmotorwithtwoinputs(Va,Td)andoneoutput(w):h1=tf(Km,[LR]);%armatureh2=tf(1,[JKf]);%eqnofmotiondcm=ss(h2)*[h1,1];%w=h2*(h1*Va+Td)dcm=feedback(dcm,Kb,1,1);%closebackemfloopNote:Computewiththestate-spaceformtominimizethemodelorder
5、.NowplottheangularvelocityresponsetoastepchangeinvoltageVa:stepplot(dcm(1));Right-clickontheplotandselect"Characteristics:SettlingTime"todisplaythesettlingtime.FeedforwardDCMotorControlDesignYoucanusethissimplefeedforwardcontrolstructuretocommandtheangularvel
6、ocitywtoagivenvaluew_ref.ThefeedforwardgainKffshouldbesettothereciprocaloftheDCgainfromVatow.Kff=1/dcgain(dcm(1))Kff=4.1000Toevaluatethefeedforwarddesigninthefaceofloaddisturbances,simulatetheresponsetoastepcommandw_ref=1withadisturbanceTd=-0.1Nmbetweent=5and
7、t=10seconds:t=0:0.1:15;Td=-0.1*(t>5&t<10);%loaddisturbanceu=[ones(size(t));Td];%w_ref=1andTdcl_ff=dcm*diag([Kff,1]);%addfeedforwardgaincl_ff.InputName={'w_ref','Td'};cl_ff.OutputName='w';h=lsimplot(cl_ff,u,t);title('Setpointtrackinganddisturbancerejection')le
8、gend('cl_ff')%Annotateplotline([5,5],[.2,.3]);line([10,10],[.2,.3]);text(7.5,.25,{'disturbance','T_d=-0.1Nm'},...'vertic','middle','horiz','center','color','r');Clearlyfeedforwardcontrol
