Table Of ContentTeam Cooperation in a Network of Multi-Vehicle
Unmanned Systems
Elham Semsar-Kazerooni • Khashayar Khorasani
Team Cooperation in a
Network of Multi-Vehicle
Unmanned Systems
Synthesis of Consensus Algorithms
123
ElhamSemsar-Kazerooni KhashayarKhorasani
UniversityofToronto DepartmentElectrical&Computer
Toronto,Canada Engineering
ConcordiaUniversity
MontrealQue´bec,Canada
ISBN978-1-4614-5072-6 ISBN978-1-4614-5073-3(eBook)
DOI10.1007/978-1-4614-5073-3
SpringerNewYorkHeidelbergDordrechtLondon
LibraryofCongressControlNumber:2012950316
©SpringerScience+BusinessMediaNewYork2013
Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof
thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,
broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation
storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology
nowknownorhereafterdeveloped.Exemptedfromthislegalreservationarebriefexcerptsinconnection
with reviews or scholarly analysis or material supplied specifically for the purpose of being entered
and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of
this publication or parts thereof is permitted only under the provisions of the Copyright Law of the
Publisher’slocation,initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer.
PermissionsforusemaybeobtainedthroughRightsLinkattheCopyrightClearanceCenter.Violations
areliabletoprosecutionundertherespectiveCopyrightLaw.
Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublication
doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant
protectivelawsandregulationsandthereforefreeforgeneraluse.
While the advice and information in this book are believed to be true and accurate at the date of
publication,neithertheauthorsnortheeditorsnorthepublishercanacceptanylegalresponsibilityfor
anyerrorsoromissionsthatmaybemade.Thepublishermakesnowarranty,expressorimplied,with
respecttothematerialcontainedherein.
Printedonacid-freepaper
SpringerispartofSpringerScience+BusinessMedia(www.springer.com)
To MyParents,and
MyHusband,Amin
ElhamSemsar-Kazerooni
To MyFamily
KhashayarKhorasani
Preface
Recently,therehasbeenagrowinginteresttowardsdevelopmentofsensornetwork
(SN)systems,ormorebroadlydefinedasnetworkofunmannedsystems(NUMS),
thatcanoperateautonomouslyforanextendedperiodoftimewithoutanextensive
involvementofhumanoperators.Thisareahasattractedasignificantlevelofinterest
in the past few years and is currently considered as one of the strategic areas of
researchinthefieldofsystemscontroltheory.Themotivationforthisinterestmay
betracedto applicationswheredirecthumaninterventionorinvolvementis either
notpossibleornotsafeduetoenvironmentalhazards,extraordinarycomplexityof
tasks involved, or other restrictions. On the other hand, observations made based
on natural behavior of animals operating as a team have inspired scientists in
differentdisciplinestoinvestigatethepossibilitiesofnetworkingagroupofsystems
(systemofsystems)toaccomplishagivensetoftaskswithoutrequiringanexplicit
supervisor.Someexamplesofsuchnaturalbehaviorscanbefoundinthemigration
ofbirds,motionoffish searchingforfood,andteamworkofotheranimalswhich
haveagrouplivingstyle.Inalltheseexamples,theanimalsworktogetherasateam
with an intergroup cooperation and with no supervision from outside the team in
ordertoperformtheircomplextasks.Furthermore,itshouldbenotedthatadvances
inwirelesscommunicationnetworkshavemadeitfeasibletoconnectanumberof
systemsdistributedoveralargegeographicarea.
These advances and observations, among other factors, have led the scientists
to concentrate and focus on the area of network of unmanned systems. The
advantagesof NUMS are numerousand applications in various fields of research
arebeingdeveloped.Someoftheadvantagesfordeployingautonomousnetworkof
unmannedsystemsareenhancedgrouprobustnesstoindividualfaults,increasedand
improvedinstrumentsensingandresolution,reducedcostofoperation,andadaptive
reconfigurabilitycapabilities [13]. These networks of dynamical systems are then
required and tasked to cooperate in order to accomplish complicated tasks which
arehighlynovelandchallengingandwhichotherwisewouldhavebeenimpossible
to accomplish by using only a single unit. These networks may be potentially
constructedfromintegratingalargenumberofdynamicalsystems(agents),suchas
unmannedaerialvehicles(UAVs),unmannedgroundvehicles(UGVs), unmanned
vii
viii Preface
underwater vehicles (UUVs), satellites [as in precision formation flight (PFF)],
or mobile robots. Any one of the above systems usually consists of a number of
sensors,actuators,anddecisionmakers,andthereforethenetworkofthesesystems
isanetworkofpotentiallylargenumberofsensorsandactuators,orasisknownin
the literature, a sensor–decider–actuatornetwork. In order to fully take advantage
of these large-scale networks, several prerequisites have to be satisfied. Some
of these prerequisites are developmentof reliable communication, optimal power
consumptionmanagement,security,optimalcooperation,andteamcollaborationas
discussedin[119].
Team cooperation and coordination for accomplishing predefined goals and
requirementsconstituteasoneofthemainprerequisitesforthesenetworkedmulti-
agent systems as they are intended to be deployed in challenging and complex
missions. Although,a large bodyof literaturehasfocused on team cooperationin
variouscontexts,mostoftheproposedstrategiesarenotbasedonrigoroussynthesis
approaches. This book seeks to propose and develop synthesis-based strategies
for team cooperation in a network by designing optimal consensus algorithms.
Towards this end, a frameworkfor modelling and controlof a network of mobile
robots in a cooperative manner is developed. Specifically, two control algorithms
are designedforconsensus-seekingproblemin sucha network.First, the problem
is solved by utilizing optimal control theory and by solving the corresponding
Hamilton–Jacobi–Bellman (HJB) equations. The consensus problem is formally
defined and solved for a team of dynamical systems having a linear dynamical
model.Stabilityoftheteamisguaranteedbyusingmodifiedconsensusalgorithms
that are derived by minimizing a set of individual cost functions. An alternative
approach for obtaining an optimal consensus algorithm is presented by invoking
a state decomposition methodology and by transforming the consensus-seeking
problemintoastabilizationproblem.
In the second methodology,the game theoryapproachis used to formulatethe
consensus-seeking problem in a strictly cooperative framework. For this purpose,
the team cost function is defined and the corresponding min–max problem is
solved in order to obtain a cooperative optimal solution. It is shown that the
resultsobtainedyield lowercost valueswhencomparedto those thatare obtained
by using the optimal control technique. In both approaches based on the game
theoryandthestatedecompositiontechnique,linearmatrixinequalitiesareusedto
simultaneouslyimpose:(a)thedecentralizedrequirementofthesolutionsoughtand
(b) the consensus constraints on the resulting designed controllers. Moreover,the
performanceandstabilitypropertiesofthedesignedcooperativeteamareanalyzed
inthepresenceofactuatoranomaliescorrespondingtothreetypesoffaults.Steady
state behavior of the team members is also analyzed under faulty scenarios. The
adaptability of the team members to unanticipated circumstances is demonstrated
and verified formally. Finally, the assumption of having a fixed and undirected
networktopologyisrelaxedinordertoaddressandsolvemorerealisticandpractical
scenarios.Specifically,itisshownthatstabilityandconsensusachievementofthe
networksubjecttobothrandomswitchingstructuresandleaderassignmentchanges
Preface ix
can still be achieved. Moreover, by introducing additional criteria, the desirable
performancespecificationsoftheteamcanstillbeensuredandguaranteed.
This book is mainly intended and targeted for researchers, scientists, and
graduate-level university students who are interested in becoming familiar with
designofconsensus-seekingalgorithmsinthegeneralareaofnetworkeddynamical
systems.Thefundingformuchoftheresearchreportedinthisbookwasprovided
bythesupportfromthenaturalsciencesandengineeringresearchcouncilofCanada
(NSERC).Thesecondauthorwouldalsoliketosincerelyacknowledgethefunding
support he has received as a Tier I Concordia University Research Chair and the
supportfromtheFacultyofEngineeringandComputerScience.
Toronto,Canada E.Semsar–Kazerooni
Montreal,Canada K.Khorasani
