Simulation of dynamic systems with MATLAB and Simulink

786 Pages·2007·10.608 MB·English

by  Klee, Harold

KLEE: “44184_c000” — 2007/1/31 — 13:59 — page i — #1
KLEE: “44184_c000” — 2007/1/31 — 13:59 — page ii — #2
KLEE: “44184_c000” — 2007/1/31 — 13:59 — page iii — #3
KLEE: “44184_c000” — 2007/1/31 — 13:59 — page iv — #4
Dedication
WhoelsebutmywifeLaura, andkidsAndrewandCassiewhoenduredprolongedabsencesfrom
ahusbandandfatheroverthepast5years.
v
KLEE: “44184_c000” — 2007/1/31 — 13:59 — page v — #5
KLEE: “44184_c000” — 2007/1/31 — 13:59 — page vi — #6
Foreword
As the author points out in his preface, there is not yet extant a universally accepted definition
of the term simulation. Another approach to defining the field would be “the art of reproducing
thebehaviorofasystemforanalysiswithoutactuallyoperatingthatsystem.”Dr.Kleehaswritten
aseminaltextcoveringthesimulationdesignandanalysisofabroadvarietyofsystemsusingtwo
ofthemodernsoftwarepackagesavailabletoday. Thematerialispresentedinaparticularlyadept
fashionenablingstudentsnewtothefieldtogainathoroughunderstandingofthebasicsofcontinuous
simulationinasinglesemester,atthesametimeprovidingamoreadvancedtreatmentofthesubject
for researchers and simulation professionals. The author’s extensive treatment of continuous and
discrete linear system fundamentals opens the door to simulation for individuals without formal
educationinatraditionalengineeringcurriculum.
Howeverdefined,simulationisbecominganincreasinglyimportantcomponentofcurriculain
engineering,businessadministration,thesciences,appliedmathematics,andthelike.Thistextwill
beavaluableresourceforstudyincoursesusingsimulationasatoolforunderstandingprocesses
whicharenotamenabletostudyinotherways.
ChrisBauer,Ph.D.,P.E.,C.M.S.P.
Simulationhascomealongwaysincethedaysanalogcomputersfilledentirerooms.Yet,itismore
importantthaneverthatsimulationsbeconstructedwithcare,knowledge,andalittlewisdom,lest
theresultsbegibberish, orworse, reasonablebutmisleading. Usedproperly, simulationscangive
usextraordinaryinsightintotheprocessesandstatesofaphysicalsystem. Constructedwithcare,
simulationscansavetimeandmoneyintoday’scompetitivemarketplace.
Onemajorapplicationofsimulationisthesimulator,whichprovidesinteractionbetweenamodel
andapersonthroughsomeinterface.Theearliestsimulator,EdLink’s“PilotMaker”aircrafttrainer,
didn’tuseanyofthesimulationtechniquesdescribedinthisbook.Modernsimulatorshowever,such
astheNationalAdvancedDrivingSimulator(NADS),cannotbefullyunderstoodwithoutthem.
ThemissionoftheNADSisaloftyone:tosavelivesonU.S.highwaysthroughsafetyresearch
usingrealistichuman-in-the-loopsimulation.Thisisanexampleoftheimportancesimulationhas
attained in our generation. The pervasiveness of simulation tools in our society will only increase
over time; and it will be more important than ever that future scientists and engineers be familiar
withtheirtheoryandapplication.
The contents of Harold Klee’s text, “Simulation of Dynamic Systems with MATLAB and
Simulink,” are arranged to give the student a gradual and natural progression through the import-
ant topics in simulation. Advanced concepts are added only after complete examples have
been constructed using fundamental methods. The use of Matlab and Simulink provides exper-
ience with tools that are widely adopted in industry, and allow easy construction of simulation
models.
May your experience with simulation be enjoyable and fruitful, and extend throughout your
careers.
ChrisSchwarz
IowaCity
vii
KLEE: “44184_c000” — 2007/1/31 — 13:59 — page vii — #7
KLEE: “44184_c000” — 2007/1/31 — 13:59 — page viii — #8
Preface
InthefirstarticleofSimulationmagazineinthefallof1963, theeditorJohnMcLeodproclaimed
simulationtomean“theactofrepresentingsomeaspectsoftherealworldbynumbersorsymbols
whichmaybeeasilymanipulatedtofacilitatetheirstudy.”Twoyearslater,itwasmodifiedto“the
developmentanduseofmodelsforthestudyofthedynamicsofexistingorhypothesizedsystems.”
Morethan40yearslater,thesimulationcommunityhasyettoconvergeuponauniversallyaccepted
definition.Eitherofthetwociteddefinitionsorotherswhichfollowedconveyabasicnotion,namely,
thatsimulationisintendedtoreinforceorsupplementone’sunderstandingofasystem.Thedefinitions
varyintheirdescriptionoftoolsandmethodstoaccomplishthis.
Thefieldofsimulationisexperiencingexplosivegrowthinimportancebecauseofitsabilityto
improvethewaysystemsandpeopleperform,inasafeandcontrollableenvironment,atareduced
cost. Understanding the behavior of complex systems with the latest technological innovations in
fields such as transportation, communication, medicine, aerospace, meteorology, and so forth, is
adauntingtask. Itrequiresanassimilationoftheunderlyingnaturallawsandscientificprinciples
thatgoverntheindividualsubsystemsandcomponents.Amultifacetedapproachisrequired,onein
whichsimulationcanplayaprominentrole,bothinthevalidationofasystem’sdesignandtraining
ofpersonneltobecomeproficientinitsoperation.
Simulationisasubjectwhichcutsacrosstraditionalacademicdisciplines.Airplanecrewsspend
hours flying simulated missions in aircraft simulators to become proficient in the use of onboard
subsystemsduringnormalflightandpossibleemergencyconditions.Astronautsspendyearstraining
inshuttleandorbitersimulatorstoprepareforfuturemissionsinspace.Powerplantandpetrochemical
processoperatorsareexposedtosimulationtoobtainpeaksystemperformance.Economistsresortto
simulationmodelstopredicteconomicconditionsofmunicipalitiesandcountriesforpolicymakers.
Simulationsofnaturaldisastersaidinthepreparationandplanningofmitigatingthepossibilityof
catastrophiceffects.
Whilethemathematicalmodelscreatedbyaircraftdesigners,nuclearengineers,andeconomists
areapplicationspecific,manyoftheequationsareanalogousinformdespitethemarkedlydifferent
phenomenadescribedbyeachmodel. Simulationofferspractitionersfromeachofthesefieldsthe
toolstoexploresolutionsofthemodelsasanalternativetoexperimentingwiththerealsystem.
Thisbookismeanttoserveasanintroductiontothefundamentalconceptsofcontinuoussys-
tem simulation, a branch of simulation applied to dynamic systems whose signals change over a
continuum of points in time or space. Our concern is with mathematical models of continuous-
timesystems(electriccircuits,thermalprocesses,populationdynamics,vehiclesuspension,human
physiology,andsoforth),andthediscrete-timesystemmodelscreatedtosimulatethem.Thecon-
tinuoussystemmathematicalmodelsconsistofacombinationofalgebraicandordinarydifferential
equations.Thediscrete-timesystemmodelsareamixofalgebraicanddifferenceequations.
Systemswhichtransitionbetweenstatesatrandomlyoccurringtimesarecalleddiscrete-event
systems.Discrete-eventsimulationisacomplementarybranchofsimulation,separatefromcontinu-
ous system simulation, with a mathematical foundation rooted in probability theory. Examples of
discrete-eventsystemsarefacilitiessuchasabank,tollbooth,supermarket,orhospitalemergency
room,wherecustomersarriveandareservicedinsomeway.Amanufacturingplantinvolvingmul-
tipleproductionstagesofuncertaindurationtogenerateafinishedproductisanothercandidatefor
discrete-eventsimulation.
ix
KLEE: “44184_c000” — 2007/1/31 — 13:59 — page ix — #9