机械毕业设计英文外文翻译467四轮转向汽车的转向特性及控制技术副本.docx

机械毕业设计英文外文翻译467四轮转向汽车的转向特性及控制技术副本.docx

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机械毕业设计英文外文翻译467四轮转向汽车的转向特性及控制技术副本

附　　录

附录A

SteeringBehaviorandControlTechnology

0fFour—wheelSteeringAutomobiIe

ABSTRACT

Thispaperanalysesthecharacteristicsofcarfour-wheelsteeringcontrolto,summarizestheprincipleofconstructionfour-wheelsteeringcars.Introducedthefour-wheelsteeringsystemcontrolstrategy.Pointsoutthefour-wheelsteeringsystemcontroltechnologyfacesdifficulties,andprospectsthetrendofitsdevelopment.

Keywords:

four-wheelsteering;Steeringcharacteristics;Workingprinciple;Control;Development;

1.Introduction

Withmodernroadtrafficsystemandthedevelopmentofmodernautomobiletechnology,peopleonthecar'ssteeringcontrolperformanceanddrivingstabilityrequirementisincreasingdaybyday.Asthemosteffectiveimprovevehiclehandlingperformanceofakindofactivechassiscontroltechnology-four-wheelsteeringtechnology.Inthe1980sbeganincarsgetapplication,andasthemodernautomobileindustryandcontinuousdevelopment.Carfour-wheelsteeringmeansinturn,therearcarcanberelativetobodyactivesteering,thatthecarcanbeuptofourwheelsrole.Toimprovethecarturnedtomaneuverability,handlingstabilityanddrivingsafety.

2.Thecar'ssteeringfour-wheelsteering

2.14wscarsand2wssteeringprocessanalysis

Ordinarytwowheelsteeringcannotonlythefrontcararounditsownwheelrotationandrelativetobodydeflectionaroundtheprecision,thenwheelrotationandnotonlydeflection.Whenthedriverturnedthesteeringwheel,frontwheelsteering,changeddirectionsfacefronttyre,producedatransverseforce,throughthefrontwheeleffectonbody,makethebodyyawingandproducecentrifugalforce,therearwheelscornering,producedchangedirection,participateinthesportscarto.Andtherearandfrontcar4wsas,canrotationcanalsodeflection.Whenthedriverturnedthesteeringwheel,frontandrearwheels,thatcaralmostatthesametimetochangedirection,realizesteeringmovement.

Inturn,the2wscarbeforeactivesteeringwheelrotationjustmakespassivesteering.Obviously,2wscarsinsteeringprocessfromthesteeringwheelrotationtorearwheelsteeringmovementinbetweentheexistenceofcertainlagtime.Thisphaselag2wsautomobilesteeringcharacteristicsmaketheservosexbecomespoor,andthatthecarsteeringradiusincreased.Inaddition,2wscaratahighspeed,thesteeringwheelAnglerelativetocertainincremental,bodyyaw-rateandlateralaccelerationincrementalincreases,madethecaratahighspeedhandlingandstabilitybecomespoor.Andinturn,thecar4wshasdonebefore,rearwheelsteering,activeintheprocessofsteering,highsensitivity,fastresponse,effectivelyovercometheshortcomings.

2.24wsautomobilesteeringway

Accordingtothetheoryanalysisandroadtestshowedthatafour-wheelsteeringcanimprovethemaneuverabilityandsteeringcontrolstabilityofhighspeed,modern4wscarisdevelopedaccordingtotheguidingideology.Generallyspeaking,intheprocessofsteeringcarsin4ws,accordingtodifferentdrivingconditions,frontandrearwheelsteeringAngleshouldfollowcertainrulesbetween.Atpresent,thefront,reartypical4wsdeflectionrulesgenerallyaredescribedbelow:

（a）inversephasesteering

AsshowninfigureA1（a）shows,steeringwheelAngleatlowspeedsorlarger,frontandrearinversephaseshift,realizethattherearwheelswiththefrontdeflectdeflectinstead,andwiththesteeringwheelAngledeflectionAngleincreasesandincreasesinacertainrange.Thisredirectionspeedwaycanimprovethemanipulationofthecar,reduceautomobileportabilityturningradius,makingcarsmaneuverability.Easycarturnedturn,obstacleavoidanceanddriving,garageandparking.Asforcars,ifrearinversephase5°,thenturnedcanreduceminimumsteeringradiuswasabout0.5.

（b）phasewithsteering

AsshowninfigureA1（b）shows,inahigh-speedorsteeringwheelAngleislesser,frontandrearwheelswithphaseshift,realizethattherearwheelsdeflectthedeflectiondirectionwithfrontwheel.Makethecarbodyyaw-rategreatlyreduceautomobilebody,canreducethetendencyofcorneringundergodynamic,guaranteetheovertakingthehighway,elevatedhighway,inandout,intheapproachandflyoversinsufficientsteeringstate.Now,therearemany4wscarstakeimprovingvehiclehandlingperformancefocusesonmakingcarsonhigh-speedsteeringstability,withoutexcessivedemandsinlow-speeddrivingcarcourse-alteringmaneuversflexibility.Thefeaturesislowbyfrontwheelsteeringcaronlywhenonlyincarspeeds,afteruptoacertainvalue,rear,onlyparticipateinsteeringphasewithfour-wheelsteering.

（a）Reverseasteering（b）Coincidentalasteering

FigureA1four-wheelsteeringthefrontofthecar,reardeflectionrule

3.Four-wheelsteeringcarcomponentsandworkingcharacteristics

4wscarisinfrontwheelsteeringsystem,andonthebasisofsuspensionincarsoninstallasetofrearwheelsteeringsystem,boththroughcertainquestionsofcontact,makingcarsinfrontwheelsteeringalsoparticipateinthemeanwhile,rearwheelsteering.Afterdecadesofresearchanddevelopment,havemolding4wscartypehasavarietyof,composition,structureisdifferent,workingprincipleandcontrolmethodsvary.Thetypicalelectric4wssystemmainlybythefrontwheelsteeringsystem,sensors,ECU,rearwheelsteeringactuatorsandrearwheelsteeringtransmissionmechanismetc.thesensorwillfrontwheelsteeringmotorsportsthesignalandthesignalintoECUwereanalyzedandcalculated,willprocessafterthedrivesignaltorearwheelsteeringactuators,rearwheelsteeringactuatorsaction,throughtherearwheelsteeringtransmissionmechanism,rearwheeldeflection.Meanwhile,ECUwhencarriedoutmonitoringcaroperationcondition,calculatetargetsteeringAngleandrearreal-timesteeringAngle,thedifferenceinvaluebetweenreal-timeadjustmenttorearwheelscorner.Such,canaccordingtotheactualsportscar,torealizethestatecarfour-wheelsteering.General4wscarsequippedwithtwoturningmode,canenter4wsstate,alsocankeepthetraditional2wsstate,driverscanpassthedrivingindoorsteeringmodeswitchselection.When4wscarinthecourseofdrivingtheelectroniccontrolsystemmalfunction,rearwheelautomaticbackintothemiddle,theautomaticintothefrontwheelsteeringstate,ensurelikeordinaryfrontwheelsteeringcardrivingsafelyasautomobiles.Meanwhile,dashboard"4ws"indicator,warningdrivers,storedonECUfaultconditionofwarranty,sothatbyyards.

4.Four-wheelsteeringcontrolofthecar

4wssystemnotonlytorealizetheneedforautomotivesteeringmovement,andguaranteethevehiclesteeringtravelingstability.Atpresent,intheresearchanddevelopmentofautomobile4wscenteredonimprovingcar,thetransientmanipulationstabilityasastartingpoint,exploreduetorearbroughtcarinresponsetochanges,andadoptsvariousrearwheelcontrolstrategyandproducedifferenteffect.Autofour-wheelsteeringcontroldependsontireswerelateralforce,four-wheelsteeringcanmakecarsinturn,thereardirectlyinvolvedinforcaryawingmovementandlateralizingcontrol.Throughtimely,accuratecontroloftherearwheelsteeringAngle,notonlycanshortentheprocessofsteeringthetransientresponse,andcanactivelycontrolcarsthetrajectoryandattitude.Inturn,thatthecarduringitslongitudinaldirectioncenterlineofthedirection,evenwiththedirectionofthecarhorndecreasesoverlap,attitudeAngleofsteeringbodyworkcornering,improvesthelateralstabilitycar.

4.1controlgoals

ThatcarinturntobasickeepPianJiaozerogravitysidecar.Socangreatlyimprovethecartothesteeringwheelinputdynamicresponsecharacteristics,largelyimprovedyaw-rateandlateralaccelerationoftransientperformanceindicators,lowerthebodyposturechange.FromthePianJiaozerotargetstart.Accordingtocertaincontrolprogramistorealizetherearwheelstofunctionisderivedbasedfour-wheelsteering.Ofcourse,themodern4wscarsalsohavesomeothercontrolgoalrequest.

4.2controlstrategymodelbased

Thegeneralsituationofthestudiesare4wssystembasedonasimpledofvehiclemodeloflinear.Thisisjustakindofutopianmathematicalmodel,whenmodelingoverlookedinsomeofthedynamicparametersofthecarwithoutconsideringchanges,automobiledrivingproducesintheprocessofmanyoftherandomuncertaintiesandnotveryaccurate.Early4wscontrollerdesignarebasedonlineardynamicequationwiththehypothesis,butduetotheabovereasons,makethedesignofcontrolsystemdoesn'tmeetpracticalneeds,thereisnoguaranteethatthevehiclesteeringcontrolstability.

4.3controlmethod

Differentcarsdrivingperformancerequirementsofsteeringanddifferentmodelsofthecarwheelsdeflection4wslawisnotthesame.Thus,different4wsvehicleUSEScontrolmethodisendlessandsame,variouscontrolmethodhasitsemphasesrespectively.Atpresent,insomemolding4wswithcaronthecontrolmethodbasicallyhas:

（a）.Thesetthansimplysteeringsystem4ws.

（b）.Thanbefore,rearwheelsteeringfront-wheelcornerfunction4wssystem.

（c）.Thanbefore,rearwheelsteeringjspeedfunction4wssystemis.

（d）.The4wswithfirst-orderlaggingsystem.

（e）.Withreversed-phasecharacteristics4wssystem

（f）.Withoptimalcontrolcharacteristicsof4wssystem.

（g）.Hassincelearning,whitetheabilitytoadjustthe4wssystem.

Formerfivekindsofcontrolsystembelongtoclassicalcontroltheorycategory,onlytosatisfycarundercertainconditions,butalsocan'tadapttotheneedofmotorsportsofrandom