动力转向系统概述 文献集翻译

1英文题目POWERSTEERINGSYSTEMOVERVIEW中文题目动力转向系统概述院系飞行学院专业交通运输班级学生姓名指导教师职称2011年6月日2POWERSTEERINGSYSTEMOVERVIEWALONGWITHAUTOMOBILEELECTRONICTECHNOLOGYSWIFTANDVIOLENTDEVELOPMENT,THEPEOPLEALSODAYBYDAYENHANCETOTHEMOTORTURNINGHANDLINGQUALITYREQUESTTHEMOTORTURNINGSYSTEMCHANGED,THEHYDRAULICPRESSUREBOOSTFROMTHETRADITIONALMACHINERYCHANGESHYDRAULICPOWERSTEERING,ISCALLEDHPS,THEELECTRICALLYCONTROLLEDHYDRAULICPRESSUREBOOSTCHANGESELECTRICHYDRAULICPOWERSTEERING,ISCALLEDEHPS,DEVELOPSTHEELECTRICALLYOPERATEDBOOSTSTEERINGSYSTEMELECTRICPOWERSTEERING,ISCALLEDEPS,FINALLYALSOWILLTRANSITTOTHELINECONTROLSTHESTEERINGSYSTEMSTEERBYWIRE,WILLBECALLEDSBWTHEMACHINERYSTEERINGSYSTEMISREFERSBYPILOTSPHYSICALSTRENGTHACHIEVEMENTCHANGESTHEENERGY,INWHICHALLPOWERTRANSMISSIONALLISMECHANICAL,THEAUTOMOBILECHANGESTHEMOVEMENTISOPERATESTHESTEERINGWHEELBYTHEPILOT,TRANSMITSTHROUGHTHEDIVERTERANDASERIESOFMEMBERSCHANGESTHEWHEELTOREALIZETHEMECHANICALSTEERINGSYSTEMBYCHANGESTHECONTROLMECHANISM,THEDIVERTERANDMAJORPARTCHANGESTHEGEARING3TOBECOMPOSEDUSUALLYMAYDIVIDEINTOACCORDINGTOTHEMECHANICALDIVERTERFORMTHEGEARRACKTYPE,FOLLOWSROUNDTHEWORLDLIKE,THEWORMBEARINGADJUSTERHOOPTYPE,THEWORMBEARINGADJUSTERREFERSSELLSTHETYPEISTHEGEARRACKTYPEANDFOLLOWSUSINGTHEBROADESTTWOKINDSROUNDTHEWORLDLIKEUSESINNEEDINGTIMEBIGSTEERINGFORCEINFOLLOWSROUNDTHEWORLDLIKEINTHEDIVERTER,THEINPUTCHANGESTHECIRCLEANDTHEOUTPUTSTEERINGARMPIVOTANGLEISPROPORTIONALINTHEGEARRACKTYPEDIVERTER,THEINPUTCHANGESTHETURNANDTHEOUTPUTRACKDISPLACEMENTISPROPORTIONALFOLLOWSROUNDTHEWORLDLIKETHEDIVERTERBECAUSEISTHEROLLINGFRICTIONFORM,THUSTHETRANSMISSIONEFFICIENCYISVERYHIGH,THEEASEOFOPERATIONALSOTHESERVICELIFEARELONG,MOREOVERBEARINGCAPACITY,THEREFOREWIDELYAPPLIESONTHETRUCKTHEGEARRACKTYPEDIVERTERWITHFOLLOWSROUNDTHEWORLDLIKECOMPARES,THEMOSTMAJORCHARACTERISTICISTHERIGIDITYISBIG,THESTRUCTURECOMPACTWEIGHTISLIGHT,ALSOTHECOSTISLOWBECAUSETHISWAYPASSESONEASILYBYTHEWHEELTHEREACTINGFORCETOTHESTEERINGWHEEL,THEREFOREHASTOTHEPAVEMENTBEHAVIORRESPONSEKEENMERIT,BUTSIMULTANEOUSLYALSOEASYTOHAVEPHENOMENAANDSOONGOONANDOSCILLATION,ALSOITSLOADBEARINGEFFICIENCYRELATIVEWEAK,THEREFOREMAINLYAPPLIESONTHECOMPACTCARANDTHEPICKUPTRUCK,ATPRESENTTHEMAJORITYOFLOWENDPASSENGERVEHICLEUSESISTHEGEARRACKTYPEMACHINERYSTEERINGSYSTEM3ALONGWITHTHEVEHICLESCARRYINGCAPACITYINCREASEASWELLASTHEPEOPLETOTHEVEHICLESHANDLINGQUALITYREQUESTENHANCEMENT,THESIMPLEMECHANICALTYPESTEERINGSYSTEMWEREALREADYUNABLETOMEETTHENEEDS,THEPOWERSTEERINGSYSTEMARISEATTHEHISTORICMOMENT,ITCOULDROTATETHESTEERINGWHEELWHILETHEPILOTTOPROVIDETHEBOOST,THEPOWERSTEERINGSYSTEMDIVIDESINTOTHEHYDRAULICPRESSURESTEERINGSYSTEMANDTHEELECTRICALLYOPERATEDSTEERINGSYSTEM2KINDSHYDRAULICPRESSURESTEERINGSYSTEMISATPRESENTUSESTHEMOSTWIDESPREADSTEERINGSYSTEMTHEHYDRAULICPRESSURESTEERINGSYSTEMINCREASEDTHEHYDRAULICSYSTEMINTHEMECHANICALSYSTEMFOUNDATION,INCLUDINGHYDRAULICPUMP,VSHAPEBANDPULLEY,DRILLTUBING,FEEDINSTALLMENT,BOOSTINSTALLMENTANDCONTROLVALVEITWITHTHEAIDOFINTHEMOTORCARENGINEPOWERACTUATIONHYDRAULICPUMP,THEAIRCOMPRESSORANDTHEGENERATORANDSOON,BYTHEFLUIDSTRENGTH,THEPHYSICALSTRENGTHORTHEELECTRICPOWERINCREASESTHEPILOTTOOPERATETHESTRENGTHWHICHTHEFRONTWHEELCHANGES,ENABLESTHEPILOTTOBEPOSSIBLENIMBLYTOOPERATEMOTORTURNINGFACILELY,REDUCEDTHELABORINTENSITY,ENHANCEDTHETRAVELSECURITYTHEHYDRAULICPRESSUREBOOSTSTEERINGSYSTEMFROMINVENTEDALREADYHADABOUTHALFCENTURYHISTORYTOTHEPRESENT,MIGHTSAYWASONEKINDOFMOREPERFECTSYSTEM,BECAUSEITSWORKRELIABLE,THETECHNOLOGYMATURESTILLWIDELYISAPPLIEDUNTILNOWITTAKESTHEPOWERSUPPLYBYTHEHYDRAULICPUMP,AFTEROILPIPELINECONTROLVALVESTOPOWERHYDRAULICCYLINDERFEED,THROUGHTHECONNECTINGRODIMPETUSROTATIONGEARMOVEMENT,MAYCHANGESTHEBOOSTTHROUGHTHECHANGECYLINDERBOREANDTHEFLOWINGTUBINGHEADPRESSURESIZETHESIZE,FROMTHISACHIEVEDCHANGESTHEBOOSTTHEFUNCTIONTHETRADITIONALHYDRAULICPRESSURETYPEPOWERSTEERINGSYSTEMMAYDIVIDEINTOGENERALLYACCORDINGTOTHELIQUIDFLOWFORMORDINARYFLOWTYPEANDATMOSPHERICPRESSURETYPE2KINDOFTYPES,ALSOMAYDIVIDEINTOACCORDINGTOTHECONTROLVALVEFORMTRANSFERSTHEVALVETYPEANDTHESLIDEVALVETYPEALONGWITHHYDRAULICPRESSUREPOWERSTEERINGSYSTEMONAUTOMOBILEDAILYPOPULARIZATION,THEPEOPLETOOPERATESWHENTHEPORTABILITYANDTHEROADFEELINGREQUESTALSODAYBYDAYENHANCE,HOWEVERTHEHYDRAULICPRESSUREPOWERSTEERINGSYSTEMHASMANYSHORTCOMINGSACTUALLYBECAUSEITSITSELFSTRUCTUREHADDECIDEDITISUNABLETOGUARANTEEVEHICLESROTATESTHESTEERINGWHEELWHENANYOPERATINGMODE,ALLHASTHEIDEALOPERATIONSTABILITY,NAMELYISUNABLESIMULTANEOUSLYTOGUARANTEETIMETHELOWSPEEDCHANGESTHEPORTABILITYANDTHEHIGHSPEEDTIMEOPERATIONSTABILITYTHEAUTOMOBILECHANGESTHECHARACTERISTICTODRIVETHEPILOTTECHNICALTHEINFLUENCETOBESERIOUSTHESTEERINGRATIOISFIXED,CAUSESTHEMOTORTURNINGRESPONSECHARACTERISTICALONGWITHCHANGESANDSOONVEHICLE4SPEED,TRANSVERSEACCELERATIONTOCHANGE,THEPILOTMUSTAIMATTHEMOTORTURNINGCHARACTERISTICPEAKTOPEAKVALUEANDTHEPHASECHANGEAHEADOFTIMECARRIESONCERTAINOPERATIONCOMPENSATION,THUSCONTROLSTHEAUTOMOBILEACCORDINGTOITSWISHTRAVELLIKETHISINCREASEDPILOTSOPERATIONBURDEN,ALSOCAUSESINTHEMOTORTURNINGTRAVELNOTTOHAVETHESECURITYHIDDENDANGERBUTHEREAFTERAPPEAREDTHEELECTRICALLYCONTROLLEDHYDRAULICBOOSTERSYSTEM,ITINCREASESTHEVELOCITYGENERATORINTHETRADITIONALHYDRAULICPRESSUREPOWERSTEERINGSYSTEMFOUNDATION,ENABLESTHEAUTOMOBILEALONGWITHTHEVEHICLESPEEDCHANGEAUTOMATICCONTROLFORCESIZE,HASTOACERTAINEXTENTRELAXEDTHETRADITIONALHYDRAULICPRESSURESTEERINGSYSTEMEXISTENCEQUESTIONATPRESENTOURCOUNTRYPRODUCESONTHECOMMERCIALVEHICLEANDTHEPASSENGERVEHICLEUSESMOSTLYISTHEELECTRICALLYCONTROLLEDHYDRAULICPRESSUREBOOSTSTEERINGSYSTEM,ITISQUITEMATUREANDTHEAPPLICATIONWIDESPREADSTEERINGSYSTEMALTHOUGHTHEELECTRICALLYCONTROLLEDHYDRAULICSERVOALLEVIATEDTHETRADITIONALHYDRAULICPRESSUREFROMCERTAINDEGREETOCHANGEBETWEENTHEPORTABILITYANDTHEROADFEELINGCONTRADICTION,HOWEVERITDIDNOTHAVEFUNDAMENTALLYTOSOLVETHEHPSSYSTEMEXISTENCEINSUFFICIENCY,ALONGWITHAUTOMOBILEMICROELECTRONICTECHNOLOGYDEVELOPMENT,AUTOMOBILEFUELOILENERGYCONSERVATIONREQUESTASWELLASGLOBALINITIATIVEENVIRONMENTALPROTECTION,ITINASPECTANDSOONARRANGEMENT,INSTALLMENT,LEAKPROOFQUALITY,CONTROLSENSITIVITY,ENERGYCONSUMPTION,ATTRITIONANDNOISEINSUFFICIENCIESALREADYMOREANDMOREOBVIOUS,THESTEERINGSYSTEMTURNEDTOWARDSTHEELECTRICALLYOPERATEDBOOSTSTEERINGSYSTEMDEVELOPMENTTHEELECTRICALLYOPERATEDBOOSTSTEERINGSYSTEMISTHEPRESENTMOTORTURNINGSYSTEMDEVELOPMENTDIRECTION,ITSPRINCIPLEOFWORKISEPSSYSTEMECUAFTERCOMESFROMTHESTEERINGWHEELTORQUESENSORANDTHEVEHICLESPEEDSENSORSIGNALCARRIESONANALYSISPROCESSING,CONTROLSTHEELECTRICALMACHINERYTOHAVETHESUITABLEBOOSTTORQUE,ASSISTSTHEPILOTTOCOMPLETECHANGESTHEOPERATIONINTHELASTFEWYEARS,ALONGWITHTHEELECTRONICTECHNOLOGYDEVELOPMENT,REDUCESEPSTHECOSTTOBECOMELARGESCALEPOSSIBLY,JAPANSENDSTHECARCOMPANY,MITSUBISHICARCOMPANY,THISFIELDCARCOMPANY,USSDELPHIAUTOMOBILESYSTEMCOMPANY,TRWCORPORATIONANDGERMANYSZFCORPORATIONGREATLYALLONEAFTERANOTHERDEVELOPSEPSMERCEDES2BENZANDSIEMENSAUTOMOTIVETWOBIGCOMPANIESINVESTED65,000,000POUNDSTOUSEINDEVELOPINGEPS,THEGOALARETOGETHERLOADACARTO2002,YEARLYPRODUCE300TENTHOUSANDSETS,BECAMETHEGLOBALEPSMANUFACTURERSOFAR,THEEPSSYSTEMINTHESLIGHTPASSENGERVEHICLE,ONTHETHEATERBOXTYPEVEHICLEOBTAINSTHEWIDESPREADAPPLICATION,ANDEVERYYEARBY300TENTHOUSANDSPEEDDEVELOPMENT5ELECTRICALLYPOWEREDSTEERINGUSESANELECTRICMOTORTODRIVEEITHERTHEPOWERSTEERINGHYDRAULICPUMPORTHESTEERINGLINKAGEDIRECTLYTHEPOWERSTEERINGFUNCTIONISTHEREFOREINDEPENDENTOFENGINESPEED,RESULTINGINSIGNIFICANTENERGYSAVINGSCONVENTIONALPOWERSTEERINGSYSTEMSUSEANENGINEACCESSORYBELTTODRIVETHEPUMP,PROVIDINGPRESSURIZEDFLUIDTHATOPERATESAPISTONINTHEPOWERSTEERINGGEARORACTUATORTOASSISTTHEDRIVERINELECTROHYDRAULICSTEERING,ONEELECTRICALLYPOWEREDSTEERINGCONCEPTUSESAHIGHEFFICIENCYPUMPDRIVENBYANELECTRICMOTORPUMPSPEEDISREGULATEDBYANELECTRICCONTROLLERTOVARYPUMPPRESSUREANDFLOW,PROVIDINGSTEERINGEFFORTSTAILOREDFORDIFFERENTDRIVINGSITUATIONSTHESYSTEMHASLOTSOFADVANTAGESINPUTSFROMTHESTEERINGSENSORALLOWYOUTOMAKEANINFORMEDDECISIONTHEPUMPCANBERUNATLOWSPEEDORSHUTOFFTOPROVIDEENERGYSAVINGSDURINGSTRAIGHTAHEADDRIVINGWHICHISMOSTOFTHETIMEINMOSTWORLDMARKETSDIRECTELECTRICSTEERINGUSESANELECTRICMOTORATTACHEDTOTHESTEERINGRACKVIAAGEARMECHANISMNOPUMPORFLUIDAVARIETYOFMOTORTYPESANDGEARDRIVESISPOSSIBLEAMICROPROCESSORCONTROLSSTEERINGDYNAMICSANDDRIVEREFFORTINPUTSINCLUDEVEHICLESPEEDANDSTEERING,WHEELTORQUE,ANGULARPOSITIONANDTURNINGRATEINPUTSFROMTHESTEERINGSENSORAREDIGESTEDBYAMICROPROCESSORCONTROLUNITTHATALSOMONITORSINPUTFROMTHEVEHICLESSPEEDSENSORTHESENSORINPUTSARETHENCOMPAREDTODETERMINEHOWMUCHPOWERASSISTISREQUIREDACCORDINGTOAPREPROGRAMMED“FORCEMAP“INTHECONTROLUNITSMEMORYTHECONTROLUNITTHENSENDSOUTTHEAPPROPRIATECOMMANDTOTHE“POWERUNIT“WHICHTHENSUPPLIESTHEELECTRICMOTORWITHCURRENTTHEMOTORPUSHESTHERACKTOTHERIGHTORLEFTDEPENDINGONWHICHWAYTHEVOLTAGEFLOWSREVERSINGTHECURRENTREVERSESTHEDIRECTIONTHEMOTORSPINSINCREASINGTHECURRENTTOTHEMOTORINCREASESTHEAMOUNTOFPOWERASSISTIFTHESTEERINGWHEELISTURNEDANDHELDINTHEFULLLOCKPOSITIONANDSTEERINGASSISTREACHESAMAXIMUM,THECONTROLUNITREDUCESCURRENTTOTHEELECTRICMOTORTOPREVENTANOVERLOADSITUATIONTHATMIGHTDAMAGETHEMOTORTHECONTROLUNITISALSODESIGNEDTOPROTECTTHEMOTORAGAINSTVOLTAGESURGESFROMAFAULTYALTERNATORORCHARGINGPROBLEMTHEELECTRONICSTEERINGCONTROLUNITISCAPABLEOFSELFDIAGNOSINGFAULTSBYMONITORINGTHESYSTEMSINPUTSANDOUTPUTS,ANDTHEDRIVINGCURRENTOFTHEELECTRICMOTORIFAPROBLEMOCCURS,THECONTROLUNITTURNSTHESYSTEMOFFBYACTUATINGAFAILSAFERELAYINTHEPOWERUNITTHISELIMINATESALLPOWERASSIST,CAUSINGTHESYSTEMTOREVERTBACKTOMANUALSTEERINGADASH6EPSWARNINGLIGHTISALSOILLUMINATEDTOALERTTHEDRIVERTODIAGNOSETHEPROBLEM,ATECHNICIANJUMPSTHETERMINALSONTHESERVICECHECKCONNECTORANDREADSOUTTHETROUBLECODESELECTRICPOWERSTEERINGSYSTEMSPROMISEWEIGHTREDUCTION,FUELSAVINGSANDPACKAGEFLEXIBILITY,ATNOCOSTPENALTYEUROPESHIGHFUELPRICESANDSMALLERVEHICLESMAKEAFERTILETESTBEDFORELECTRICSTEERING,ATECHNOLOGYTHATPROMISESAUTOMAKERSWEIGHTSAVINGSANDFUELECONOMYGAINSANDINASHORTTIME,ELECTRICSTEERINGWILLMAKEITTOTHEUS,TOO“ITSJUSTJUSTAMATTEROFTIME,“SAYSALYBADAWY,DIRECTOROFRESEARCHANDDEVELOPMENTFORDELPHISAGINAWSTEERINGSYSTEMSINSAGINAW,MICH“THEISSUEWASCOSTANDTHATSBEHINDUSNOWBY2002HEREINTHEUSTHECOSTOFELECTRICPOWERSTEERINGWILLABSOLUTELYBEAWASHOVERHYDRAULIC“TODAY,ELECTRICANDHYBRIDPOWEREDVEHICLESEV,INCLUDINGTOYOTASPRIUSANDGMSEV1,ARETHEPERFECTDOMAINFORELECTRICSTEERINGIN1995,ACCORDINGTODELPHI,TRADITIONALHYDRAULICPOWERSTEERINGSYSTEMSWEREON7596OFALLVEHICLESSOLDGLOBALLYTHAT37MILLIONVEHICLEPOOLCONSUMESABOUT10MILLIONGALLONSINHYDRAULICFLUIDTHATCOULDBESUPERFLUOUS,IFELECTRICSTEERINGREALLYTAKESOFFELECTRONICPOWERSTEERINGSYSTEMENGLISHASEPS,ANDHYDRAULICPOWERSTEERINGSYSTEMHPSCOMPAREDTO,EPSHASMANYADVANTAGESTHEADVANTAGEISTHATTHEEPS1HIGHEFFICIENCYHPSEFFICIENCYISVERYLOW,GENERALLY60TO70,WHILEEPSANDELECTRICALCONNECTIONS,HIGHEFFICIENCY,ANDSOMECANBEASHIGHAS90PERCENT2LESSENERGYCONSUMPTIONAUTOMOBILETRAFFICINTHEACTUALPROCESS,ATTHETIMETOABOUT5PERCENTOFTHETIMETRAVELLING,THEHPSSYSTEM,ENGINERUNNING,THEPUMPSWILLALWAYSBEINWORKINGCONDITION,THEOILPIPELINEHASBEENINCIRCULATION,SOTHATVEHICLEFUELCONSUMPTIONRATEBY4TO6,WHILEEPSONLYWHENNEEDEDFORENERGY,VEHICLEFUELCONSUMPTIONRATESONLYINCREASEDBY05PERCENT3“ROADSENSEOF“GOODBECAUSEEPSINTERNALUSEOFRIGID,SYSTEMOFTHELAGCANBECONTROLLEDBYSOFTWARE,ANDCANBEUSEDINACCORDANCEWITHTHEOPERATIONOFTHEDRIVERTOADJUST4BACKTOBEINGGOODEPSSIMPLESTRUCTUREOFSMALLINTERNALRESISTANCE,ISAGOODBACK,GETBACKTOBEINGTHEBESTCHARACTERISTICS,IMPROVEVEHICLEHANDLINGANDSTABILITY5LITTLEENVIRONMENTALPOLLUTIONHPSHYDRAULICCIRCUITINTHEHYDRAULICHOSESANDCONNECTORS,THEEXISTENCEOFOILLEAKING,BUTHYDRAULICHOSESCANNOTBERECOVERED,THE7ENVIRONMENTALPOLLUTIONARETOACERTAINEXTENT,WHILEEPSALMOSTNOPOLLUTIONTOTHEENVIRONMENT6CANBEINDEPENDENTOFTHEENGINESWORKEPSFORBATTERYPOWEREDDEVICES,ASLONGASSUFFICIENTBATTERYPOWER,NOMATTERWHATTHECONDITIONFORTHEENGINE,CANPRODUCEPOWERROLE7SHOULDHAVEAWIDERANGE8EASYTOASSEMBLEANDGOODLAYOUTSTEERINGISTHETERMAPPLIEDTOTHECOLLECTIONOFCOMPONENTS,LINKAGES,ETCWHICHALLOWFORAVESSELSHIP,BOATORVEHICLECARTOFOLLOWTHEDESIREDCOURSEANEXCEPTIONISTHECASEOFRAILTRANSPORTBYWHICHRAILTRACKSCOMBINEDTOGETHERWITHRAILROADSWITCHESPROVIDETHESTEERINGFUNCTIONTHEMOSTCONVENTIONALSTEERINGARRANGEMENTISTOTURNTHEFRONTWHEELSUSINGAHANDOPERATEDSTEERINGWHEELWHICHISPOSITIONEDINFRONTOFTHEDRIVER,VIATHESTEERINGCOLUMN,WHICHMAYCONTAINUNIVERSALJOINTSTOALLOWITTODEVIATESOMEWHATFROMASTRAIGHTLINEOTHERARRANGEMENTSARESOMETIMESFOUNDONDIFFERENTTYPESOFVEHICLES,FOREXAMPLE,ATILLERORREARWHEELSTEERINGTRACKEDVEHICLESSUCHASTANKSUSUALLYEMPLOYDIFFERENTIALSTEERINGTHATIS,THETRACKSAREMADETOMOVEATDIFFERENTSPEEDSOREVENINOPPOSITEDIRECTIONSTOBRINGABOUTACHANGEOFCOURSEMANYMODERNCARSUSERACKANDPINIONSTEERINGMECHANISMS,WHERETHESTEERINGWHEELTURNSTHEPINIONGEARTHEPINIONMOVESTHERACK,WHICHISASORTOFLINEARGEARWHICHMESHESWITHTHEPINION,FROMSIDETOSIDETHISMOTIONAPPLIESSTEERINGTORQUETOTHEKINGPINSOFTHESTEEREDWHEELSVIATIERODSANDASHORTLEVERARMCALLEDTHESTEERINGARMOLDERDESIGNSOFTENUSETHERECIRCULATINGBALLMECHANISM,WHICHISSTILLFOUNDONTRUCKSANDUTILITYVEHICLESTHISISAVARIATIONONTHEOLDERWORMANDSECTORDESIGNTHESTEERINGCOLUMNTURNSALARGESCREWTHE“WORMGEAR“WHICHMESHESWITHASECTOROFAGEAR,CAUSINGITTOROTATEABOUTITSAXISASTHEWORMGEARISTURNEDANARMATTACHEDTOTHEAXISOFTHESECTORMOVESTHEPITMANARM,WHICHISCONNECTEDTOTHESTEERINGLINKAGEANDTHUSSTEERSTHEWHEELSTHERECIRCULATINGBALLVERSIONOFTHISAPPARATUSREDUCESTHECONSIDERABLEFRICTIONBYPLACINGLARGEBALLBEARINGSBETWEENTHETEETHOFTHEWORMANDTHOSEOFTHESCREWATEITHERENDOFTHEAPPARATUSTHEBALLSEXITFROMBETWEENTHETWOPIECESINTOACHANNELINTERNALTOTHEBOXWHICHCONNECTSTHEMWITHTHEOTHERENDOFTHEAPPARATUS,THUSTHEYARE“RECIRCULATED“THERACKANDPINIONDESIGNHASTHEADVANTAGESOFALARGEDEGREEOFFEEDBACKANDDIRECTSTEERING“FEEL“ITALSODOESNOTNORMALLYHAVEANYBACKLASH,ORSLACKADISADVANTAGEISTHAT8ITISNOTADJUSTABLE,SOTHATWHENITDOESWEARANDDEVELOPLASH,THEONLYCUREISREPLACEMENTTHERECIRCULATINGBALLMECHANISMHASTHEADVANTAGEOFAMUCHGREATERMECHANICALADVANTAGE,SOTHATITWASFOUNDONLARGER,HEAVIERVEHICLESWHILETHERACKANDPINIONWASORIGINALLYLIMITEDTOSMALLERANDLIGHTERONESDUETOTHEALMOSTUNIVERSALADOPTIONOFPOWERSTEERING,HOWEVER,THISISNOLONGERANIMPORTANTADVANTAGE,LEADINGTOTHEINCREASINGUSEOFRACKANDPINIONONNEWERCARSTHERECIRCULATINGBALLDESIGNALSOHASAPERCEPTIBLELASH,OR“DEADSPOT“ONCENTER,WHEREAMINUTETURNOFTHESTEERINGWHEELINEITHERDIRECTIONDOESNOTMOVETHESTEERINGAPPARATUSTHISISEASILYADJUSTABLEVIAASCREWONTHEENDOFTHESTEERINGBOXTOACCOUNTFORWEAR,BUTITCANNOTBEENTIRELYELIMINATEDORTHEMECHANISMBEGINSTOWEARVERYRAPIDLYTHISDESIGNISSTILLINUSEINTRUCKSANDOTHERLARGEVEHICLES,WHERERAPIDITYOFSTEERINGANDDIRECTFEELARELESSIMPORTANTTHANROBUSTNESS,MAINTAINABILITY,ANDMECHANICALADVANTAGETHEMUCHSMALLERDEGREEOFFEEDBACKWITHTHISDESIGNCANALSOSOMETIMESBEANADVANTAGEDRIVERSOFVEHICLESWITHRACKANDPINIONSTEERINGCANHAVETHEIRTHUMBSBROKENWHENAFRONTWHEELHITSABUMP,CAUSINGTHESTEERINGWHEELTOKICKTOONESIDESUDDENLYLEADINGTODRIVINGINSTRUCTORSTELLINGSTUDENTSTOKEEPTHEIRTHUMBSONTHEFRONTOFTHESTEERINGWHEEL,RATHERTHANWRAPPINGAROUNDTHEINSIDEOFTHERIMTHISEFFECTISEVENSTRONGERWITHAHEAVYVEHICLELIKEATRUCKRECIRCULATINGBALLSTEERINGPREVENTSTHISDEGREEOFFEEDBACK,JUSTASITPREVENTSDESIRABLEFEEDBACKUNDERNORMALCIRCUMSTANCESTHESTEERINGLINKAGECONNECTINGTHESTEERINGBOXANDTHEWHEELSUSUALLYCONFORMSTOAVARIATIONOFACKERMANNSTEERINGGEOMETRY,TOACCOUNTFORTHEFACTTHATINATURN,THEINNERWHEELISACTUALLYTRAVELINGAPATHOFSMALLERRADIUSTHANTHEOUTERWHEEL,SOTHATTHEDEGREEOFTOESUITABLEFORDRIVINGINASTRAIGHTPATHISNOTSUITABLEFORTURNSASVEHICLESHAVEBECOMEHEAVIERANDSWITCHEDTOFRONTWHEELDRIVE,THEEFFORTTOTURNTHESTEERINGWHEELMANUALLYHASINCREASEDOFTENTOTHEPOINTWHEREMAJORPHYSICALEXERTIONISREQUIREDTOALLEVIATETHIS,AUTOMAKERSHAVEDEVELOPEDPOWERSTEERINGSYSTEMSTHEREARETWOTYPESOFPOWERSTEERINGSYSTEMSHYDRAULICANDELECTRIC/ELECTRONICTHEREISALSOAHYDRAULICELECTRICHYBRIDSYSTEMPOSSIBLEAHYDRAULICPOWERSTEERINGHPSUSESHYDRAULICPRESSURESUPPLIEDBYANENGINEDRIVENPUMPTOASSISTTHEMOTIONOFTURNINGTHESTEERINGWHEELELECTRICPOWERSTEERINGEPSISMOREEFFICIENTTHANTHEHYDRAULICPOWERSTEERING,SINCETHEELECTRICPOWERSTEERINGMOTORONLYNEEDSTOPROVIDEASSISTWHENTHESTEERINGWHEELISTURNED,WHEREASTHEHYDRAULICPUMPMUSTRUNCONSTANTLYINEPSTHEASSISTLEVELISEASILYTUNABLETOTHEVEHICLETYPE,ROADSPEED,ANDEVENDRIVERPREFERENCEANADDEDBENEFITISTHEELIMINATIONOFENVIRONMENTALHAZARDPOSED9BYLEAKAGEANDDISPOSALOFHYDRAULICPOWERSTEERINGFLUIDANOUTGROWTHOFPOWERSTEERINGISSPEEDADJUSTABLESTEERING,WHERETHESTEERINGISHEAVILYASSISTEDATLOWSPEEDANDLIGHTLYASSISTEDATHIGHSPEEDTHEAUTOMAKERSPERCEIVETHATMOTORISTSMIGHTNEEDTOMAKELARGESTEERINGINPUTSWHILEMANOEUVERINGFORPARKING,BUTNOTWHILETRAVELINGATHIGHSPEEDTHEFIRSTVEHICLEWITHTHISFEATUREWASTHECITRONSMWITHITSDIRAVILAYOUT,ALTHOUGHRATHERTHANALTERINGTHEAMOUNTOFASSISTANCEASINMODERNPOWERSTEERINGSYSTEMS,ITALTEREDTHEPRESSUREONACENTRINGCAMWHICHMADETHESTEERINGWHEELTRYTO“SPRING“BACKTOTHESTRAIGHTAHEADPOSITIONMODERNSPEEDADJUSTABLEPOWERSTEERINGSYSTEMSREDUCETHEPRESSUREFEDTOTHERAMASTHESPEEDINCREASES,GIVINGAMOREDIRECTFEELTHISFEATUREISGRADUALLYBECOMINGCOMMONPLACEACROSSALLNEWVEHICLESFOURWHEELSTEERINGORALLWHEELSTEERINGISASYSTEMEMPLOYEDBYSOMEVEHICLESTOINCREASEVEHICLESTABILITYWHILEMANEUVERINGATHIGHSPEED,ORTODECREASETURNINGRADIUSATLOWSPEEDINMOSTFOURWHEELSTEERINGSYSTEMS,THEREARWHEELSARESTEEREDBYACOMPUTERANDACTUATORSTHEREARWHEELSGENERALLYCANNOTTURNASFARASTHEALTERNATIVELY,SEVERALSYSTEMS,INCLUDINGDELPHISQUADRASTEERANDTHESYSTEMINHONDASPRELUDELINE,ALLOWFORTHEREARWHEELSTOBESTEEREDINTHEOPPOSITEDIRECTIONASTHEFRONTWHEELSDURINGLOWSPEEDSTHISALLOWSTHEVEHICLETOTURNINASIGNIFICANTLYSMALLERRADIUSSOMETIMESCRITICALFORLARGETRUCKSORVEHICLESWITHTRAILERSNOW,POWERSTEERINGSYSTEMSOFSOMECARSHAVEBECOMETHESTANDARDSETTING,THEWHOLEWORLDABOUTHALFOFTHECARSUSEDTOPOWERSTEERINGWITHTHEDEVELOPMENTOFAUTOMOTIVEELECTRONICSTECHNOLOGY,SOMECARSHAVEBEENUSINGELECTRICPOWERSTEERINGGEAR,THECAROFTHEECONOMY,POWERANDMOBILITYHASIMPROVEDELECTRICPOWERSTEERINGDEVICEONTHECARISANEWPOWERSTEERINGSYSTEMDEVICE,DEVELOPEDRAPIDLYINRECENTYEARSBOTHATHOMEANDABROAD,BECAUSEOFITSUSEOFPROGRAMMABLEELECTRONICCONTROLDEVICES,THEFLEXIBILITYINTHESAMETIMETHEREAREALSOPOTENTIALSAFETYPROBLEMSINTHEANALYSISTHISUNIQUEPRODUCTONTHEBASISOFTHEAUTHOROFTHECHARACTERISTICSOFELECTRONICCONTROLDEVICES,SECURITYCLEARANCEJUSTTHATTHEFACTORSTHATDEALWITHSECURITYMEASURES,ANDDISCUSSEDANUMBEROFCONCERNSTHESAFETYOFSPECIFICISSUESTHERESULTSSHOWTHATEXISTINGSTANDARDSCANNOTMEETTHEELECTRICPOWERSTEERINGDEVICESECURITYNEEDSANDMADETHEELECTRICPOWERSTEERINGDEVICESAFETYEVALUATIONOFTHEIDEARESEARCHWORKONTHEELECTRICPOWERSTEERINGDEVICEDEVELOPMENTANDEVALUATIO