Methods and Tools for Co-Simulation of Dynamic Systems with the Functional Mock-up Interface PDF
Preview Methods and Tools for Co-Simulation of Dynamic Systems with the Functional Mock-up Interface
Methods and Tools for Co-Simulation of Dynamic Systems with the Functional Mock-up Interface byChristianAndersson ACADEMICTHESIS which, by due permission of the Faculty of Engineering at Lund University, will be publicly defended on Wednesday4thofMay,,at.inlecturehallMH:A,attheCentreforMathematicalSciences,Sölveg- atan,Lund,forthedegreeofDoctorofPhilosophyinEngineering. Facultyopponent:Dr.CarolWoodward,LawrenceLivermoreNationalLaboratory,USA Organization Documentname LUNDUNIVERSITY DOCTORALDISSERTATIONIN CentreforMathematicalSciences MATHEMATICALSCIENCES Box SE-Lund Dateofdisputation Sweden May Author(s) Sponsoringorganization ChristianAndersson Titleandsubtitle MethodsandToolsforCo-SimulationofDynamicSystemswiththeFunctionalMock-upInterface Abstract Simulationofcoupleddynamicalsystems,whereeachsubsystemisbundledwithaninternalsolver,isanimpor- tantindustrialmethodtosupportmodel-baseddesignworkflows.isisduetothatinmanycases,withcomplex systems,thisistheonlyviableoptioninheterogeneoussimulationlandscapeswheredifferentpartsofasystem aremodeledindifferentsimulationtools.Inthissetting,thedynamicsofeachsystemishiddenandinformation betweensubsystemsisexchangedthroughsampledinputsandoutputs.isisoftendenotedasaweaklycoupled system.Whileanewindustrialstandardforexchangingmodels,theFunctionalMock-upInterface(FMI),gains increasingacceptance,thenumericalconsequencesoftreatingcomplexsystemsinthiswayarenotcompletely understood. Inthisthesis,stabilityquestionsofweaklycoupledlinearsystemswithfeed-througharestudied.Newmethods, withinthescopeoftheFMI,areproposedwhichofferimprovedstabilitypropertiescomparedtotheclassical approaches. Asimulationofaweaklycoupledsystemintroducesdiscontinuitiesduetoinputchangesfortheinternalsolvers. Iftheinternalsolverisamultistepmethod, thesediscontinuitieswillresultinperformancedegradation. To avoidthedegradation,amodificationofthepredictorinamultistepmethodisproposedachievingincreased performance. Furthermore,twoPythonpackagesarepresented. epackagePyFMIisahigh-levelpackageforworking withmodelscompliantwiththeFMIstandard. PyFMIalsocontainsco-simulationmastersforsimulationof weaklycoupledsystems. epackageAssimulounifiesdifferentintegratorsunderacommoninterfacewhich, togetherwithPyFMI,providesanenvironmentforusingandevaluatingsolversonindustrialmodels.epackages aredemonstratedbyvariousexamplesrangingfromsimpletestcasestoamoreextensiveindustrialapplication. Additionally,theyhavebeenusedtoverifytheproposedmethodsandpredictormodification. Keywords FunctionalMock-upInterface,FMI,Co-Simulation,CoupledSystems,MasterAlgorithm,Stability,Assimulo, PyFMI Classificationsystemand/orindexterms(ifany) Supplementarybibliographicalinformation Language English ISSNandkeytitle ISBN - ----(print) ----(digital) Recipient'snotes Numberofpages Price Securityclassification I,theundersigned,beingthecopyrightowneroftheabstractoftheabove-mentioneddissertation,herebygrantto allreferencesourcesthepermissiontopublishanddisseminatetheabstractoftheabove-mentioneddissertation. Signature Date March Methods and Tools for Co-Simulation of Dynamic Systems with the Functional Mock-up Interface Christian Andersson Faculty of Engineering Centre for Mathematical Sciences Numerical Analysis Numerical Analysis Centre for Mathematical Sciences Lund University Box 118 SE-221 00 Lund Sweden http://www.maths.lth.se/ Doctoral Theses in Mathematical Sciences 2016:3 ISSN 1404-0034 ISBN 978-91-7623-697-0 (print) ISBN 978-91-7623-698-7 (digital) LUTFNA-1010-2016 ⃝c Christian Andersson, 2016 Printed in Sweden by Media-Tryck, Lund 2016 Abstract Simulationofcoupleddynamicalsystems,whereeachsubsystemisbundledwithaninter- nal solver, is an important industrial method to support model-based design workflows. is is due to that in many cases, with complex systems, this is the only viable option in heterogeneous simulation landscapes where different parts of a system are modeled in different simulation tools. In this setting, the dynamics of each system is hidden and in- formationbetweensubsystemsisexchangedthroughsampledinputsandoutputs. isis oftendenotedasaweaklycoupledsystem. Whileanewindustrialstandardforexchanging models,theFunctionalMock-upInterface(FMI),gainsincreasingacceptance,thenumer- icalconsequencesoftreatingcomplexsystemsinthiswayarenotcompletelyunderstood. Inthisthesis,stabilityquestionsofweaklycoupledlinearsystemswithfeed-throughare studied. New methods, within the scope of the FMI, are proposed which offer improved stabilitypropertiescomparedtotheclassicalapproaches. Asimulationofaweaklycoupledsystemintroducesdiscontinuitiesduetoinputchanges for the internal solvers. If the internal solver is a multistep method, these discontinuities will result in performance degradation. To avoid the degradation, a modification of the predictorinamultistepmethodisproposedachievingincreasedperformance. Furthermore, twoPythonpackagesarepresented. epackagePyFMIisahigh-level packageforworkingwithmodelscompliantwiththeFMIstandard. PyFMIalsocontains co-simulation masters for simulation of weakly coupled systems. e package Assimulo unifiesdifferentintegratorsunderacommoninterfacewhich, togetherwithPyFMI,pro- videsanenvironmentforusingandevaluatingsolversonindustrialmodels. epackages are demonstrated by various examples ranging from simple test cases to a more extensive industrial application. Additionally, they have been used to verify the proposed methods andpredictormodification. iv Populärvetenskaplig sammanfattning Utvecklingavnyaindustriellaprodukterskeralltoftaremedhjälpavdatormodeller. Dessa modellerbeskriverfysikenförrespektiveprodukt,vilketexempelviskanvaraenbilellerett kraftverk. Medhjälpavmodellernakanenstordelavanalysernapådeframtidaproduk- ternaskemedhjälpavdatorer,varförfärreprototyperbehöverkonstrueras,vilketmedför kortareutvecklingstidersamtkostnadsbesparingar. Envanliganalyssombehövergenom- föras på en bil är exempelvis att undersöka hur bilen kommer att bete sig på varierande underlag eller vid olika manövreringar, dvs. man måste simulerar dess beteende. Utveck- lingenmotattihögregradanvändadatormodellerharpågåttunderenlängretid,menhar accelereratdesenasteåren. Ienkomplexdatormodell, somavenbil, ärdetvanligtattolikafysikaliskadomäner, t.ex. mekanikenochelektroniken,modellerasseparat. Dessaseparatamodellerskapasvan- ligtvismedhjälpavolikaverktyg. Förattsedankunnaanalyseradenkomplexabilmodellen måstedeseparatamodellernakopplassamman, vilketledertillsvårighetereftersommod- ellernabehöverkunnautbytasmellanolikaverktygsomrepresenterarmodellernapåolika vis. Med hjälp av en ny standard har emellertid utbytet av modeller mellan olika verktyg blivit lättare - eller helt enkelt möjligt. Att koppla ihop dessa modeller har lett till att det behövs nya algoritmer och fördjupad kunskap i hur man på bästa sätt simulerar dem tillsammans. Risken är dock att resultatet man får inte går att lita på eller att algoritmen misslyckasmedsimuleringen. Tilldettabehövslättillgängligmjukvaramedtillgångtillalgoritmersomärfördelaktiga för olika typer av modeller. Det här är inte bara viktigt för forskning och industrin utan äveniundervisningssyfte. I denna avhandling behandlas simulering av sammankopplade modeller, där mod- ellerna följer den nya standarden. Fokus i avhandlingen har varit att analysera olika al- goritmer, föreslår nya algoritmer, samt utveckla en mjukvara för simulering. Mjukvaran somhartagitsframhargjortspublik. vi Acknowledgements¹ Duringthecourseofthisjourney,therehavebeenanumberofpeoplewhohaveassistedand supportedme,andwithouttheirhelpthisthesiswouldneverhavehappened. Iwouldlike toexpressmysinceregratitudetowardsmysupervisors,ClausFührerandJohanÅkesson, who have guided me during this journey. Without their guidance, I would never have reachedthispoint. Also,IwouldliketothankmycolleaguesandfellowPh.D.students,currentandpast,at NumericalAnalysis,whohavemadeourcorridorintoaplaceforopendiscussions. ank youforcreatingasharingandpleasantworkingatmosphere. To my colleagues at Modelon, thank you all for the many interesting discussions and forputtingthingsintoalargerperspective. ToJohanAndreassonforprovidingtheexample modelofaracecarwhichhasbeenusedextensivelythroughoutthisthesis. Further, I’d like to thank the Centre for Mathematical Sciences, the Department of AutomaticControlandModelonformakingajointpositionpossible. I would also like to thank Anders Holmqvist with colleagues, at the Department of ChemicalEngineering, forinterestingandfruitfulcollaborationsandforlettingamathe- maticianwalkaroundinthelaboratory. Furthermore, I would like to thank my family and friends for their support and for believinginmyabilitiesevenwhenImyselfhaddoubts. Tomyfather,StefanAndersson, who always hinted that pursuing a Ph.D. might be something to aim for. To my love, HelenaSjöblom,whohaveputupwithmeduringthistimewhenIhavenotalwaysbeen myhappyself. ankyouall. ChristianAndersson Lund,Sweden ¹is work was supported in part by the Lund Center for Control of Complex Engineering Systems (LCCC),fundedbytheSwedishResearchCouncil,whichisgratefullyacknowledged.Furthermore,thework wassupportedinpartbyModelon,whichisgratefullyacknowledged. viii
Description:The list of books you might like
