Page - 62 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 1217 control systemssuchas tractioncontrol, cruisecontrol, anddifferentdrivingmodeshavebeenbeing applied inconventionalvehicles fora longtime.Applicationofsuchsystemsappearedmoreefficient inEVsas thedrivingforcesofEVscanbecontrolledwithmoreease,with lessconversionrequired in-between themechanical and the electrical domains. In anycondition, forces act onavehicle at different directions; for a driving control system, if is essential to perfectly perceive these forces, alongwith other sensory inputs, andprovide torques to thewheels tomaintain desired stability. InFigure65, the forces indifferentdirectionactingoneachwheelofacar is showninahorizontal plane. In [176],Magallan et al., proposedandsimulateda control system toutilize themaximum torque ina rear-wheel-driveEVwithout causing the tires to skid. Themodel theyworkedonhad independent driving systems for the two rearwheels. A slidingmode system, based on aLuGre dynamic frictionmodel,wasusedtoestimate thevehicle’svelocityandwheel sliponunknownroad surfaces. Utilizing thesedata, the control algorithmdetermined themaximumallowable traction force,whichwasappliedto theroadbytorquecontrollingof the tworearmotors. JuyongKangetal., presentedanalgorithmaimedatdriving control systems for four-wheel-driveEVs in [177]. Their vehiclemodelhadtwomotorsdrivingthe frontandtherearshafts. Thealgorithmhadthreeparts: a supervisory level fordetermine thedesirabledynamicsandcontrolmode,anupper levelcomputing theyawmoment and traction force inputs, anda lower level determining themotor andbraking commands. Thissystemproveduseful forenhancing lateral stability,maneuverability,andreducing rollover. Figure66showstheactingcomponentsof this systemonavehiclemodelwhileFigure67 showsadetaileddiagramof thesystemwith the inputs, controller levels, andactuators. Tahamietal., introducedastability systemfordrivingassistance for all-wheeldriveEVs in [25]. They traineda neuralnetworktoproduceareferenceyawrate.Afuzzy logiccontrollerdictated independentwheel torques;asimilarcontrollerwasusedforcontrollingwheel slip. ThissystemisshowninFigure68. In [178],Wanget al., showedasystemtoassist steeringusingdifferentialdrive for in-wheeldrive system.Aproportional integral (PI) closed loopcontrol systemwasusedhere tomonitor thereference steeringposition. Itwas achievedbydistributing torqueat the frontwheels. Direct yawmoment control and traction controlwerealso employed tomake thedifferentialdrive systembetter. This approachmaintainedthe lateral stabilityof thevehicle, andimprovedstabilityathighspeeds. The structureof this systemisshowninFigure69. Inaseparate studyconductedbyNametal., lateral stabilityofanin-wheeldriveEVwasattainedbyestimatingthesideslipangleof thevehicleemploying sensors tomeasure lateral tire forces [179]. In this study,a stateobserverwasproposedwhichwas derived fromextended-Kalman-filtering (EKF)methodandwasevaluatedby implementing inan experimentalEValongsideMatlab/Simulink-Carsimsimulations. Energymanagement isabig issue forEVs. Propermeasurementof theavailableenergy iscrucial forcalculatingtherangeandplans thedrivingstrategythereafter. Forvehicleswithmultipleenergy sources (e.g.,HEVs), efficient energymanagement algorithmsare required tomakeproperuseof the energy on-board. Zhou et al., proposed a battery state-of-charge (SOC)measuring algorithm for lithiumpolymerbatterieswhichmadeuseof a combinationofparticle filter andmulti-model data fusion technique toproduce results real timeand isnot affectedbymeasurementnoise [180]. Theyuseddifferentbatterymodelsandpresentedthe tuningstrategies foreachmodelaswell. Their multi-modelapproachprovedtobemoreeffective thansinglemodelmethods forprovidingreal time results.Workingprincipleof this systemisshowninFigure70.Mouraetal., exploredefficientways to split powerdemandamongdifferentpower sourcesofmid-sized sedanPHEVs in [175],which canbeusedforothervehicleconfigurationsaswell. Theirmethodmadeuseofdifferentdrivecycles, rather thanusing a single one; assessed thepotential of depleting charge in a controlledmanner; andconsideredrelativepricingof fuelandelectricity tooptimallymanagethepowerof thevehicle. In[181],Huietal.,presentedanovelhybridvehicleusingparallelhybridarchitecturewhichemployed ahydraulic/electric synergyconfigurationtomitigate thedrawbacks facedbyheavyhybridvehicles usingasingleenergysource. Transitionamong theoperatingmodesof suchavehicle is shownin Figure71. Theydevelopedanalgorithmtooptimize thekeyparametersandadopteda logic threshold 62