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EE475Automa,cControl
Systems
Fall2017MWF11:00-11:50am
1012CooverHall
ClassWebpage• hDp://class.ece.iastate.edu/nelia/ee475/• Pleasecheckthepagefor
– Anyannouncements– Classnotes– HWassignments– Labassignments– Projectrequirements– Classpolicyandotherinforma,on
BasicInforma-on• InstructorContactInforma-on
– NicolaElia,3131CooverHall– [email protected];294-6277– OfficeHour:12-1MWF– Oranyother-memutuallyconvenient– Pleaseinclude"EE475"inthesubjectlineinallemailcommunica,ons
toavoidauto-dele,ngorjunk-filtering
• TATBA
FinalGradeWeigh-ngSchedule
• Homeworkaverage:15%(1Hwcanbelate.LowestHWscorediscarded)
• Midtermexam1:20%• Midtermexam2:20%• Finalexam:30%• Quizzes:15%(onelowestscoresdiscarded)• Discre,onarybonus:0-5%(classpar,cipa,on,improvementtrend)
• FixedGradingScale:q A:90–100% A–:85–89.9%q B+:80–84.9% B:75–79.9% B–:70–74.9%q C+:65–69.9% C:60–64.9% C–:50–55.9%q F:<50%
CatalogDescrip-on
• EE475.Automa-cControlSystems.(3-0)Cr.3.F.Prereq:324.Stabilityandperformanceanalysisofautoma,ccontrolsystems.Thestatespace,rootlocus,andfrequencyresponsemethodsforcontrolsystemsdesign.PIDcontrolandlead-lagcompensa,on.Computertoolsforcontrolsystemanalysisanddesign.Nonmajorgraduatecredit.
Prerequisitebytopics
• KnowledgeandproficiencyinMatlab• Conceptandsolu,onoflinearordinarydifferen,alequa,ons
• Laplacetransformanditsapplica,ons• Poles,zeros,transferfunc,ons,frequencyresponse,rootlocus,Bodeplots,Nyquistplot
• Vectorsandmatrices• Complexnumbers
MainOBJECTIVES• Oncomple,onofEE475,thestudentwillbeabletodothefollowingeitherbyhandorwith
thehelpofcomputa,ontoolssuchasMatlab:• Definethebasicterminologiesusedincontrolssystems• Explainadvantagesanddrawbacksofopen-loopandclosedloopcontrolsystems• Obtainmodelsofsimpledynamicsystemsinordinarydifferen,alequa,on,transferfunc,on,statespace,
orblockdiagramform• Obtainoveralltransferfunc,onofasystemusingeitherblockdiagramalgebra,orMatlabtools.• Computeandpresentingraphicalformtheoutputresponseofcontrolsystemstotypicaltestinputsignals• Explaintherela,onshipbetweensystemoutputresponseandtransferfunc,oncharacteris,csorpole/
zeroloca,ons• Determineproper,esoftheclosedloopsystemformtheopenloopstystem.• Determinethestabilityofaclosed-loopcontrolsystemsusingMatlabtools,theRouth-Hurwitzcriteria,
theroot-locusandtheNyquistcriterion.• Analyzetheclosedloopstabilityandperformanceofcontrolsystemsbasedonopen-looptransfer
func,onsusingthefrequencyresponsetechniques• DesignPIDorlead-lagcompensatortoimprovetheclosedloopsystemstabilityandperformanceusingthe
frequencyresponsetechniques
TopicsCovered• Reviewofsignalsystemsconceptsandtechniquesasappliedtocontrolsystems• Introduc,ontomodelingofdynamicalsystemsusingode’sandstatespace
methods.• LinearTimeInvariantsystems• ModelingofLTIcontrolsystemstransferfunc,onsandblockdiagrams.• Blockdiagramsmanipula,ons• Proper,esandlimita,onofLTIfeedbacksystems• BasicanalysisanddesignprinciplesofLTIfeedbacksystemsinthefrequency
domain.• Introduc,ontouncertaintyanalysisandrobustness• Analysisofdynamicresponseofcontrolsystems,includingtransientresponse,
steadystateresponse,andtrackingperformance.• Closed-loopstabilityanalysisusingtheRouth-Hurwitzcriterion,RootLocus,
Nyquistcriterion.• Stabilityandperformanceanalysisusingthefrequencyresponsetechniques• Controlsystemdesignusingthefrequencyresponsetechniques• Ifthereis,me,Controlsystemdesignusingthestatespacetechniques
Studentbehaviorexpecta,ons• FullaDendanceexpected,exceptwithprior-no,fiedexcuses
• On-,mearrival• Ac,vepar,cipa,on
– Askques,ons– Answerques,onsfrominstructororstudents
• BecordialandconsideratetostudentsandTA• Helpeachotherinreviewingnotes,HW,Matlab• Promptlyreport/shareproblems/issues,includingtyposonslides,ormisspokenwordsfrominstructor
Prohibitedbehaviors• Anyfoullanguageorgestures• Commentstootherstudentsthatarediscriminatoryinanyform
• Anyharassmentsasdefinedbytheuniversity• Academicdishonesty
• Noalcohol,drugs,oranyotherillegal/impropersubstances– Snacks/drinksOKaslongasyoudon’tspillandcleanup
Accommoda,on/Assistance• Pleaseletmeknowifyou
– Haveanyspecialneeds– Havedisabilityinanyform– Haveanymedical/mental/emergencycondi,ons– Havefieldtrip/interview– Havespecialrequests– Wantmetoadjustlecturecontents/pace
• Canalsoconsultmeifyou– Wouldliketoseekadviceonanyprofessionalorpersonalissues
– Wouldliketohavecertainconfiden,aldiscussions
Collabora-onAndHelpingEachOther
• Fortasksintendedforgroupwork,youareexpectedtofindapartnerandsharethetasksamongthegroupmembers.Inagroupproject,effec,veteamworkiscri,caltomaximizetheproduc,vityofthewholegroup.InthesubmiDedwork,iden,fycomponentsandindicatepercentagecontribu,onbyeachmembertoeachcomponent.
• Fortasksnotintendedforgroupwork,individualsubmissionisrequired.Inthiscase,youareencouragedtodiscussamongyourfriendsonhowtoaDackproblems.However,youshouldwriteyourownsolu,on.Copyingotherpeople’sworkisstrictlyprohibited.
Academicdishonesty• Chea,ngisaveryseriousoffense.Itwillbedealtwithinthe
mostseveremannerallowableunderUniversityregula,ons.Ifcaughtchea,ng,youcanexpectafailinggradeandini,a,onofachea,ngcaseintheUniversitysystem.
• Basically,it’saninsulttotheinstructor,thedepartmentandmajorprogram,andmostimportantly,tothepersondoingthechea,ng.Justdon't.
• Ifindoubtaboutwhatmightcons,tutechea,ng,sende-mailtoyourinstructordescribingthesitua,on.Ifyouno,ceanyonechea,ng,pleasereportittotheinstructorortheTA.Donotdealwithityourself.
Disabilityaccommoda-on
• Individualswithphysicalormentalimpairmentswhoareotherwisequalifiedtoperformtheirworkorpursuetheirstudiesmayrequestreasonableaccommoda,onstoenablethemtoworkorcon,nuetheirstudies.
• Ifyoubelieveyouhavelearningdisability,youmustcontactStudentDisabilityResourcesattheAcademicSuccessCentertoini,atetheaccommoda,onprocess.
Accommoda-onforreligionbasedconflicts
• IowaStateUniversitywelcomesdiversityofreligiousbeliefsandprac,ces,recognizingthecontribu,onsdifferingexperiencesandviewpointscanbringtothecommunity.Studentswithreligionbasedconflictshouldtalktotheinstructorandappropriateuniversityofficestorequestaccommoda,onsattheearliestpossible,me.
TypesofControlSystems
➸ Open-Loop– Simplecontrolsystemwhichperformsitsfunc,onwith-outconcernsforini,alcondi,onsorexternalinputs.
– Mustbecloselymonitored.
➸ Closed-Loop(feedback)– Usestheoutputoftheprocesstomodifytheprocesstoproducethedesiredresult.
– Con,nuallyadjuststheprocess.
System 2 System 1 Open Loop
System 2 System 1 Closed Loop
Feedback is ubiquitous in natural and engineered systems
Figure 1-1 Speed control system.
ControlSystemTerminology
• Input-Excita,onappliedtoacontrolsystemfromanexternalsource.
• Output-Theresponseobtainedfromasystem
• Feedback-Theoutputofasystemthatisreturnedtomodifytheinput.
• Error-Thedifferencebetweenthereferenceinputandtheoutput.
• FeedbackControl-sensing+computa,on+actua,on
Why do we use feedback?
Robustness to Uncertainty through Feedback Feedback allows high performance in the presence of uncertainty Example: repeatable performance of amplifiers with 5X component variation Key idea: accurate sensing to compare actual to desired, correction through computation and actuation
Design of Dynamics through Feedback Feedback allows the dynamics of a system to be modified Example: stability augmentation for highly agile, unstable aircraft Key idea: interconnection gives closed loop that modifies natural behavior
X-29 experimental aircraft
AdvantagesofaClosed-LoopFeedbackSystem
➸ ReducedSensi-vitytoDisturbanceByselfcorrec,ngitminimizeseffectsofsystemchanges.
➸ IncreasedAccuracyIncreasedabilitytoreproduceoutputwithvariedinput.
➸ SmoothingandFilteringSysteminducednoiseanddistor,onarereduced.
➸ IncreasedBandwidthProducessat.responsetoincreasedrangeofinputchanges.
Control = Sensing + Computation + Actuation
Sense Vehicle Speed
Compute Control “Law”
Actuate Gas Pedal
In Feedback “Loop”
Goals Stability: system maintains desired operating point (hold steady speed) Performance: system responds rapidly to changes (accelerate to 65 mph) Robustness: system tolerates perturbations in dynamics (mass, drag, etc)
FeedbackSystems
Sense
Compute
Actuate • Control=
Sensing+Computa,on+Actua,on
• FeedbackPrinciples– Robustnessto
Uncertainty– DesignofDynamics
• Manyexamplesoffeedbackandcontrolinnatural&engineeredsystems:
BIO
BIO ESE
ESE
CS
ModernEngineeringApplica,onsofControl• FlightControlSystems
– Moderncommercialandmilitaryaircrarare“flybywire”
– Autolandsystems,unmannedaerialvehicles(UAVs)arealreadyinplace
• Robo,cs– Highaccuracyposi,oningfor
flexiblemanufacturing– Remoteenvironments:space,
sea,non-invasivesurgery,etc.
• ChemicalProcessControl– Regula,onofflowrates,
temperature,concentra,ons,etc.
– Long,mescales,butonlycrudemodelsofprocess
• Communica,onsandNetworks– Amplifiersandrepeaters– Conges,oncontrolofthe
Internet– Powermanagementforwireless
communica,ons• Automo,ve
– Enginecontrol,transmissioncontrol,cruisecontrol,climatecontrol,etc
– Luxurysedans:12controldevicesin1976,42in1988,67in1991
• ANDMANYMORE...
AmodernFeedbackControlSystem
AGermanan,-aircrar88mmgunwithitsfire-controlcomputerfromWorldWarII.DisplayedintheCanadianWarMuseum.
Present Position
Future Position
Ship’s Heading Range Change
Bearing Change
Present Bearing
Fire Control Problem
SolvingtheFireControlProblem
Continuously Measure Present Target Position
Stabilize Measured Quantities
Compute Relative Target Velocity
Ballistic Calculations
Relative Motion Calculations
Time of Flight
Future Target Position
Prediction Procedure
Unstabilized Launch Angles
Environmental Inputs
Launch Angles (Stabilized)
Weapons Positioning orders
Temperature control system.
Block diagram of an engineering organizational system.
Conceptualmethodofefficientwaterextrac,onusingsolarpower.
a. system concept; b. detailed layout; c. schematic; d. functional block diagram
Antenna azimuth position control system:
Importantcomponentsofthesun-trackingcontrolsystem.
Limita,onsoffeedback
• Feedbackaffectsstability!• Itcanmakeasystemunstable
• Feedbacksystemsaremorecomplextounderstand,designandimplement.
• Therearesomethingsfeedbackcannotdo• Performancestabilitytradeoffs
Responseofaposi,oncontrolsystemshowingeffectofhighandlowcontrollergainonthe
outputresponse
High gain; fast but oscillating
Control goal; fast reaction, lower overshoot, less settling time
ControlSystemsHistory
• WaD,steamenginespeedcontrolgovernor• Black,feedbackamplifiers• Minorsky,shipsteeringstability• Nyquist,closed-loopstabilityfromopen-loop• Hazen,Servomechanisms• Bode,Bodeplot,andBPbasedcontroldesign• Evans,rootlocusplot,RLbaseddesign• Kalman,statespace,controllability,Kalmanfilter• Anderson…,linearop,malcontrol
• Bellman,dynamicprogramming• Pontryagin,maximumprinciple• Lyapunov,nonlinearsystems• Sastry…,adap,vecontrol• Arimoto,learningcontrol• Doyle…,robustcontrol• Byrnes/Isidori,nonlinearregula,on• Devasia/Chen/Paden,stableinversion• Kokotovic,backstepping
ControlSystemsHistory
Commonlanguageacrossdisciplines
Feedback control is everywhere In this course you will learn the basic analysis and design principles of
feedback systems