工程基础及控制 8

第二章控制系统的数学模型Lecture504August20262of21Whatwewilllearn？基于MatLab的系统仿真Example:磁盘驱动器读取系统04August20263of21ThesimulationofsystemsusingMatlab04August20264of21Matlabbasics04August20265of21Matlabbasics04August20266of21Matlabbasics04August20267of2104August20268of21MatlabbasicsObtainaplotofthepole-zerolocationsinthecomplexplane04August20269of21Matlabbasics04August202610of21Matlabbasics04August202611of21Matlabbasics04August202612of21MatlabbasicsRemovethecommonpole-zerofactorsofatransferfunction04August202613of21Matlabbasics04August202614of21Sequentialdesignexample:

DiskdrivereadsystemGoals:Identifytheactuator,thesensor,andthecontroller.Obtainamodeloftheplantandthesensor04August202615of21Sequentialdesignexample:

DiskdrivereadsystemActuatorPermanentmagnetdcmotor(voicecoilmotor)SensorThereadheadmountedonasliderdevice.Aflexureisusedtoenabletheheadtofloatabovethedisk.Thethin-filmheadreadsthemagneticfluxandprovidesasignaltoanamplifier.AssumptionsThereadheadisaccurate,i.e.,thesensorhasaTFH(s)=1.Theflexureisentirelyrigidanddoesnotsignificantlyflex.04August202616of21Sequentialdesignexample:

DiskdrivereadsystemTheerrorsignalisprovidedbyreadingtheerrorfromaprerecordedindextrack.04August202617of21Sequentialdesignexample:

DiskdrivereadsystemParameterSymbolTypicalvalueInertiaofarmandreadheadJ1N·m·s2/radFrictionb20kg/m/sAmplifierKa10-1000ArmatureresistanceR1ΩMotorconstantKm5N·m/AArmatureinductanceL1mHTypicalparametersfordiskdrivereader04August202618of21Sequentialdesignexample:

Diskdrivereadsystem04August202619of21Sequentialdesignexample:

DiskdrivereadsystemTheblockdiagramoftheclosed-loopsystemisTheclosed-looptransferfunctionis04August202620of21Sequentialdesignexample:

DiskdrivereadsystemStepresponseforR(s)=0.1/s,Ka=4004August202621of21WhatwehavelearnttodayT