Vehicle dynamics integrated control for four-wheel

PLEASESCROLLDOWNFORARTICLEThisarticlewasdownloadedby:[VirginiaTech]On:31May2009Accessdetails:AccessDetails:[subscriptionnumber907058917]PublisherTaylor&FrancisInformaLtdRegisteredinEnglandandWalesRegisteredNumber:1072954Registeredoffice:MortimerHouse,37-41MortimerStreet,LondonW1T3JH,UKVehicleSystemDynamicsPublicationdetails,includinginstructionsforauthorsandsubscriptioninformation:~content=t713659010Vehicledynamicsintegratedcontrolforfour-wheel-distributedsteeringandfour-wheel-distributedtraction/brakingsystemsE.Onoa;Y.Hattoria;Y.Muragishia;K.KoibuchibaVehicleDynamicsControlLaboratory,ToyotaCentralR&DLabs.,Inc.,Aichi,JapanbToyotaMotorCorporation,JapanOnlinePublicationDate:01February2006TocitethisArticleOno,E.,Hattori,Y.,Muragishi,Y.andKoibuchi,K.(2006)'Vehicledynamicsintegratedcontrolforfour-wheel-distributedsteeringandfour-wheel-distributedtraction/brakingsystems',VehicleSystemDynamics,44:2,139—151TolinktothisArticle:DOI:10.1080/00423110500385790URL::–151Vehicledynamicsintegratedcontrolforfour-wheel-distributedsteeringandfour-wheel-distributedtraction/brakingsystemsE.ONO*†,Y.HATTORI†,Y.MURAGISHI†andK.KOIBUCHI‡†VehicleDynamicsControlLaboratory,ToyotaCentralR&DLabs.,Inc.,Nagakute,Aichi480-1192,Japan‡ToyotaMotorCorporation,JapanInthisarticle,vehicledynamicsintegratedcontrolalgorithmusinganon-linenon-linearoptimizationmethodisproposedfor4-wheel-distributedsteeringand4-wheel-distributedtraction/brakingsystems.Theproposeddistributionalgorithmminimizesworkloadofeachtire,whichiscontrolledtobecomethesamevalue.Theglobaloptimalityoftheconvergentsolutionoftherecursivealgorithmcanbeprovedbyextensiontoconvexproblems.Thisimpliesthattheoreticallimitedperformanceofvehicledynamicsintegratedcontrolisclarified.Furthermore,theeffectofthisvehicledynamicscontrolforthe4-wheel-distributedsteeringand4-wheel-distributedtraction/brakingsystemsisdemonstratedbysimulationtocomparewiththecombinationofthevariousactuators.Keywords:Vehicleintegratedcontrol;Non-linearoptimization;4-wheel-distributedsteering;4-wheel-distributedtraction/braking1.IntroductionThepurposeofthisarticleistheclarificationofthetheoreticallimitedperformanceofvehi-cledynamicsintegratedcontrolforsteeringandtraction/brakingsystems.Itisimportantforimprovingvehiclelimitedperformancetoestimatetyrecharacteristics.SelfAligningTorque(SAT)hascharacteristicsthatsaturatemoreinlowerlateralaccelerationturningmotionsthanlateralforce.Accordingly,anestimationalgorithmofthetyrecharacteristics,i.e.thefric-tioncircleofeachwheel,usingtherelationbetweenSATandlateralforcewasdeveloped[1,2].Althoughthesemethodscanbeappliedtopurelateralslipmotions,wehaveclarifiedtherelationbetweentyregripmarginandSATwithcombinedlateralandlongitudinalslipbyusingbrushmodel[3,4].Further,anestimationmethodoftyregripmarginwithcom-binedlateralandlongitudinalsliphasbeenproposed[5].MokhiamarandAbe[6]proposeavehicledynamicsintegratedcontrolalgorithmfor4-wheel-distributedsteeringand4-wheel-distributedtraction/brakingsystems,whichminimizesthesquaresumofworkloadsoffourwheels.However,theconstraintconcerningfrictioncircleofeachtyreisnotconsideredinthealgorithm,sothatthealgorithmdoesnotassurethatthetyreforcesofallwheelsareinfrictioncircles.*Correspondingauthor.Email:[e-mail]SSN0042-3114print/ISSN1744-5159online©2006Taylor&Francis:10.1080/00423110500385790DownloadedBy:[VirginiaTech]At:21:2231May2009140E.Onoetal.Inthisarticle,thevehicledynamicsintegratedcontrolfor4-wheel-distributedsteeringand4-wheel-distributedtraction/brakingsystemsbasedonfrictioncircleofeachwheelisproposed.Ahierarchicalcontrolstructureisadoptedforvehicledynamicscontrol[7].Thefirstlayercalculatestargetforceandthemomentofthevehicletoachieveadesirablevehiclemotioncorrespondingtothedriver’spedalinputandsteeringwheelangle.Thetargetresultantforceandthemomentofthevehiclemotionaredistributedtothetargettyreforcesofeachwheelbasedonthefrictioncircleofeachwheelinthesecondlayer.Thelastlayercontrolseachwheelmotiontoachievethetargettyreforce.EachtyregripmarginisestimatedfromSAT,andthelongitudinalandlateralforceofeachtyreforindependence.Byusingeachtyregripmargin,theradiusof