Embedded Model Predictive Control and Moving Horizon Estimation for Mechatronics Applications

222 Pages·2015·8.67 MB·English

by  Milan Vukov

ARENBERG DOCTORAL SCHOOL
Faculty of Engineering Science
Embedded Model Predictive Control
and Moving Horizon Estimation for
Mechatronics Applications
Milan Vukov
Dissertationpresentedinpartial
fulfillmentoftherequirementsforthe
degreeofDoctorinEngineeringScience
April 2015

Embedded Model Predictive Control and Moving
Horizon Estimation for Mechatronics Applications
MilanVUKOV
Examinationcommittee: Dissertationpresentedinpartial
Prof.dr.ir.D.Vandermeulen,chair fulfillmentoftherequirementsfor
Prof.dr.M.Diehl,supervisor thedegreeofDoctor
Prof.dr.ir.J.Swevers,co-supervisor inEngineeringScience
Dr.H.J.Ferreau,co-supervisor
(ABBCorporateResearch)
Prof.dr.ir.H.Bruyninckx
Prof.dr.ir.M.Moonen
Prof.dr.ir.F.Logist
Prof.dr.J.BagterpJørgensen
(TechnicalUniversityofDenmark)
April2015
©2015KULeuven–FacultyofEngineeringScience
Uitgegevenineigenbeheer,MilanVukov,KasteelparkArenberg10,B-3001Heverlee(Belgium)
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worden door middel van druk, fotokopie, microfilm, elektronisch of op welke andere wijze ook zonder
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Allrightsreserved.Nopartofthepublicationmaybereproducedinanyformbyprint,photoprint,microfilm,
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Acknowledgments
I still feel quite strange in this, new, situation. Almost four and a half years
ago,atthebeginningofmyPhDadventure,reachingtheendseemednearly
impossible.Yet,aftermanyhoursofwork,manyupsandabitmoredowns,
manycollaborationsandhelpfromanumberofveryfinepeopletheadventure
cametotheend.
MyfirstofficialmeetingwithmysupervisorMoritzDiehlwasinaparknear
NaamsepoortinLeuven.QuiteatypicalIwouldsay.LaterwhenIjoinedhis
groupIrealizedenvironmentinthegroupwasatypicalaswell,fullofflexibility.
Moritz, I would like to thank you for a given opportunity to pursue a PhD
degreeinyourgroupandsharingyourvastenthusiasmwithme.Moreover,I
amgratefulforyouralwayspositiveattitude,nomatterhowdifficultsituations
weencountered.
IwouldliketothankallthemembersofmyPhDjury,prof.JanSwevers,Hans
JoachimFerreau,prof.HermanBruyninckx,prof.MarcMoonen,prof.Filip
Logist and prof. John Bagterp Jørgensen, for their valuable comments and
remarksgivenonmyresearchandthePhDmanuscript.Inaddition,Ithank
Joachimforguidingmeintheearlystagesofmystudies,occasionallyreminding
meofthebiggerpicture.
FundingbytheEUprojectsFP7-EMBOCON,ERCHIGHWINDandEurostars
SMARTisgratefullyacknowledged.
Andrew Wagner and I spent countless hours in the kite lab. We used to
work hard, but sometimes just goofing off. Thanks for helping me out with
i
ii ACKNOWLEDGMENTS
myproblems,ideasandgivingsometimesnegativefeedbackthatmademe
thinkevenmore.Besidesworkingtogetheronresearchactivities,GregHorn
infectedmewithPythonandtaughtmetheAmericanslang.Thanksforthat!
Thanks to Sébastien Gros sometimes chaotic trains of thoughts in my mind
wereputontherighttracks.ItwasmypleasuretoworkwithGianlucaFrison.
IwishIhadmetyouearlier.BrainstormingsessionswithJoelAnderssonare
highlyappreciated.Ihavealwaysenjoyedthemverymuch.
Ihadachancetospendqualitytimeandcollaboratewithmanysmartpeople
ImetontheArenbergcampus.Here,Iwouldliketoexpressmygratitudeto
HammadAhmad,MaxBögli,JanickFrasch,KurtGeebelen,JorisGillis,Boris
Houska,TomKraus,AdelehMohammadi,ReinhartPaelinck,RienQuirynen,
MichalSalajandMarioZanon.
AbigthanksalsogoestoAlexanderDomahidiforprovidingexcellenttech
supportforhissolvers.Moreover,IamgratefultoTobiasGlückforsharinghis
pendulummodels.
Theincreasingamountofadministrativetaskswascarriedoutwiththeefficient
support from Veronique Cortens, Jacqueline De bruyn, Ida Tassens, Elsy
VermoesenandJohnVos.Thankyouverymuchforyourefforts!
DuringmyinternshipatAmpyxPowerin2013,Ihadachancetoexperiencelife
inastartup.Ithankeveryonethereformakingmefeelwelcomedandlikea
partoftheteam.Despitetheirbusyschedules,SörenandMatalwaysmanaged
tobehelpfulandenthusiastic.Thankyoualotguys!
Theex-YucrewmademystayinLeuvenevenmorememorable.Iamindebted
toIvanandBogdaninsomanyways,particularlyfortheperiodwhenIjust
movedtoLeuven.Moreover,Iowethanks,innoparticularorder,to:LićVu,
TićMa,Mire,Paja,Ilija,Marija&Topke,Ljilja,Jelena,Milica&Danilo,Dušan,
Anđelo,Gorana&Ivan,Ivana,Damjan,Marina&Bane.
MymotherDušanka,sisterJovanaandfatherRatomirhavealwaysencouraged
me,sharedtheirloveandsupport.Thankyouforbeingthereformeandmaking
thosehundredsofkilometersbetweenuslooksmall.Iwouldalsoliketothank
mymother-andfather-in-law,NadaandPetar,fortheirgeneroushelpinthe
finalstageofmyPhD.
I can hardly imagine finishing this adventure without my family, my wife
SnežanaandoursonNikola.Snežana,thankyouforjustlisteningtomystories
abouttechnical&researchrelatedsillystuff,thoughIknewmostofthemwere
ACKNOWLEDGMENTS iii
boring and uninteresting to you. Knowing how much hard for maintenance I
was,youdidareallygoodjobbeingmyvoiceofreason,patientandalways
encouraging.Thankyouforbelievinginme,thankyouforyourlimitlesslove.
Tisimojludikamenspoticanja.
MilanVukov
Leuven,April2015

Abstract
The concepts of Model Predictive Control (MPC) and Moving Horizon
Estimation (MHE) received widespread acceptance in both industry and
academia.Thisisduetotheabilitytoexplicitlydefineobjectivesandconstraints
intheframeworkofdynamicoptimization.Thosekeyfactseventuallyleadto
improvedcontrolperformance.Progressintheareaofoptimizationalgorithms
and computational hardware in the last two decades have extended the
applicability of numerical optimization to mechatronics applications. In
particular,theapplicabilitywasextendedforsmall-scalesystemswithtime
constants in micro- and millisecond range. Following the success convex
quadraticprogramming(QP)solversmadeinlinearMPC,theideashavebeen
extendedfornonlinearMPCandMHE.
This thesis aims to further reduce the gap between academia and industry.
WithoptimizedsoftwarefornonlinearMPCandMHEandextendedproblem
formulationswecanefficientlyhandlecomplexnonlinearsystems,possibly
working under nonlinear constraints. We present recent extensions to the
ACADOCodeGenerationTool(CGT).Oncespecified,theproblemstructure
isexploitedofflinebythetoolthatgeneratesthetailoredcodeoptimizedfor
executioninreal-timeenvironments.Wedemonstratethestrengthofthenewly
developedfeaturesofthetoolinnumericalsimulationsandtworeal-world
applications.
Ournumericalsimulationsshowreadinesstoeffectivelytreatproblemsonboth
shortandlonghorizons.Forthesystemswithafewstatesandfewcontrols
solution times in the microsecond range are observed. Our largest test case
involvesanMPCformulationcomprising33states,3controls,andaprediction
v
vi ABSTRACT
horizonof50steps.Thistestcasecomprises1800optimizationvariablesandis
possibletosolveonmodernhardwareinunder50milliseconds.Foranothertest
problemwherelongpredictionhorizonsarethenecessity,weobservesolution
timeslessthan4millisecondsinatestcasewiththehorizonof150steps.
ThefirstexperimentalstudyistheapplicationofnonlinearMPCandMHEtoa
laboratoryscaleoverheadcrane.Herewepresentcomputationalperformance
oftwogenerationsoftheACADOCGT.Usingtheoriginalimplementationof
thetoolandonlyanMPCcontrollerinthefirstcontrolscenario,weachieved
executiontimescloseto1millisecond.Withtherecentlyoptimizedcode,we
attainednearlythesameexecutiontimes,nowwithbothnonlinearMHEand
theMPCintheloop.Inaddition,withthemoreoptimizedcodewereached
averageruntimesforthenonlinearMPCthreetimesfasterthanwiththeoriginal
implementation.
Theaimofthesecondreal-worldapplicationistovalidatethecomputational
performanceoftheauto-generatedMHEandMPCsolversonanexperimental
setupforrotationalstart-upofanairbornewindenergysystem.Thesystem
modeldescribescomplexnonlineardynamicscomprising27differentialstates,
1 algebraic state and 4 controls. The results confirm that nonlinear MPC
formulationwithmorethan1500optimizationvariablesissolvedinjustless
than5millisecondsreducingthetotalfeedbacktimetobelow10milliseconds.