汽车论文翻译

NonlinearDynamics(2005)40:21–34c
Springer2005FuzzyLogicControlofSeatVibrationsofaNon-LinearFullVehicleModelRAHMIGUCLUFacultyofMechanicalEngineering,YildizTechnicalUniversity,Besiktas,Istanbul,Turkey(e-mail:[e-mail];fax:[phone])(Received:12January2003;accepted:9September2004)Abstract.Inthispaper,thedynamicbehaviorofanon-lineareightdegreesoffreedomvehiclemodelhavingactivesuspensionsandafuzzylogic(FL)controlledpassengerseatisexamined.Thenon-linearityoccursduetodryfrictiononthedampers.Threecasesofcontrolstrategiesaretakenintoaccount.Inthefirstcase,onlythepassengerseatiscontrolled.Inthesecondcase,onlythevehiclebodyiscontrolled.Inthethirdcase,boththevehiclebodyandthepassengerseatarefullycontrolledatthesametime.Thetimeresponsesofthenon-linearvehiclemodelduetoroaddisturbanceandthefrequencyresponsesareobtainedforeachcontrolstrategy.Attheend,theperformancesofthesestrategiesarecompared.Keywords:activesuspensions,FLcontrol,non-linearsystems,vehiclevibrationsNomenclaturea,b=distancesofaxletothecenterofgravityofthevehiclebodyc,d=distancesofunsprungmassestothecenterofgravityoftheaxlese,f=distancesofpassengerseattothecenterofgravityofthevehiclebodycsi=ithdampingcoefficientofsuspensioncs5=dampingcoefficientofpassengerseatf(Vri)=ithdryfrictionforceksi=ithspringconstantofsuspensionks5=springconstantofpassengerseatkti=ithstiffnesscoefficientoftiremi=ithmassofaxlem5=massofthepassengerxi=ithstatevariablezi(t)=ithroadexcitationIx7=massmomentofinertiaofthevehiclebodyforpitchmotionIx8=massmomentofinertiaofthevehiclebodyforrollmotionM=massofthevehiclebody1.IntroductionVehiclesuspensionservesthebasicfunctionofisolatingpassengersandthechassisfromtherough-nessoftheroadtoprovideamorecomfortableride.Duetodevelopmentsinthecontroltechnol-ogy,electronicallycontrolledsuspensionshavegainedmoreinterest.Thesesuspensionshaveactivecomponentscontrolledbyamicroprocessor.Byusingthisarrangement,significantachievementsinvehicleresponsecanbecarriedout.Selectionofthecontrolmethodisalsoimportantduringthedesignprocess.Inthisstudy,fuzzylogic(FL)controllersparalleltoMcPhersonstrut-typeinde-pendentsuspensionsareused.Themajoradvantagesofthiscontrolmethodareitssuccessandthe22R.Gucluabilityofusingthesetypesofcontrollersonvehicles.Tosimplifymodels,anumberofresearchersassumedvehiclemodelstobelinear.However,suchmodelscontainnon-linearitiesthatshouldbetakenintoaccount.Byincludingnon-linearitiessuchasdryfrictionondampers,theresultsbecomemorerealistic.Inthelastdecademanyresearchersappliedsomelinearandnon-linearcontrolmethodstovehiclemodels.Becauseofsimplicity,quartercarmodelsweremostlypreferred.RedfieldandKarnopp[1]examinedtheoptimalperformancecomparisonsofvariablecomponentsuspensionsonaquartercarmodel.Yueetal.[2]appliedlinearquadraticregulator(LQR)andlinearquadraticGaussian(LQG)controllertoaquartercarmodel.LQRisalinearoptimalfullstatefeedbackcontrolmethodwiththeobjectiveofminimizingthequadraticperformanceindex.Alinearquadraticregulatorproblemissolvedwhichassumesthatallstatesareavailableforfeedback.However,thisisnotalwaysapplicablebecauseeitheritisnotpossibletosenseallthestatesorthemeasurementisverynoisy.AKalmanfiltercanbedesignedtoestimatetheunmeasuredstates.ThecombinationoftheLQRcontrollerandKalmanfilteriscalledalinearquadraticGaussiancontroller.LQGislessrobustthanaLQR.Therefore,LQGhasnoguaranteedstabilitymargins,buthasabetternoisesuppression.SteinandBallo[3]designedadriver’sseatforoff-roadvehicleswithactivesuspensions.Hac[4]appliedoptimallinearpreviewcontrolontheactivesuspensionsofaquartercarmodel.Rakhejaetal.[5]addedapassengerseatintheiranalysis.Apassengerseatsuspensionsystemwasdescribedbyageneralizedtwodegreesoffreedommodelandwithnon-linearitiessuchasshockabsorberdamp-ing,linkagefrictionandbumpstops.Sincethequartercarmodelisinsufficienttogiveinformationabouttheangularmotionsofavehicle,someresearchersusedmorecomplexmodelslikehalfandfullcarmodels.Thesemodelsgiveinformationaboutthepitch,rollandbouncemotionsofavehiclebody.CrollaandAbdelHady[6]comparedsomeactivesuspensioncontrollawsonafullcarmodel.Integratedorfilteredwhitenoisewastakenastheroadinput.Thesameresearchersappliedlinearoptimalcontrollawtoasimilarmodelin1992.Hrovat[7]comparedtheperformancesofactiveandpassivesuspensionsystemsonquarter,halfandfullcarmodelsusinglinearquadraticoptimalcon-trol.Dryfrictionondampersisoneofthemainfactorsaffectingridecomfort.Ongoodroadsurfacesandatlowvehiclespeeds,theeffectofroadinputcannotovercomedryfrictionforceand,there-fore,thesuspensionsarealmostlocked,whichisknownasBoulevardJerk,andanuncomfortablevibrationmodebecomeseffectiveduetoreduceddegreesoffreedom[8].Someapplicationsusingnon-linearityonactivesuspensionswereachieved.Alleyneetal.[9]comparedslidingmodecon-trolledactivesuspensionswithPIDcontrolledactivesuspensionsforaquartercaractivesuspensionsystem.PIDcontrolisappliedasaconventionalmethod.Sincethiscontrolmethodcanbeappliedeasilyandwidelywellknown,ithasanimportantroleincontrolapplications.But,thismethodisnotinsensitivetoparameterchanges.Sincemodelsmighthaveuncertain