外文翻译--汽车的转向控制.doc

附录英文翻译Spincontrolforcars.Stabilitycontrolsystemsarethelatestinastringoftechnologiesfocusingonimproveddirivingsafety.Suchsystemsdetecttheinitialphasesofaskidandrestoredirectionalcontrolin40milliseconds,seventimesfastertthanthereactiontimeoftheaveragehuman.Theycorrectvehiclepathsbyadjustingenginetorqueorapplyingtheleft-or-right-sidebrakes,orboth,asneeded.ThetechnologyhasalreadybeenappliedtotheMercedes-BenzS600coupe.FullText:COPYRIGHT1995AmericanSocietyofMechanicalEngineersAutomaticstabilitysystemscandetecttheonsetofaskidandbringafishtailingvehiclebackoncourseevenbeforeitsdrivercanreact.Safetyglass,seatbelts,crumplezones,airbags,antilockbrakes,tractioncontrol,andnowstabilitycontrol.Thecontinuingprogressionofsafetysystemsforcarshasyieldedyetanotherdevicedesignedtokeepoccupantsfrominjury.Stabilitycontrolsystemshelpdriversrecoverfromuncontrolledskidsincurves,thusavoidingspinoutsandaccidents.Usingcomputersandanarrayofsensors,astabilitycontrolsystemdetectstheonsetofaskidandrestoresdirectionalcontrolmorequicklythanahumandrivercan.Everymicrosecond,thesystemtakesa"snapshot,"calculatingwhetheracarisgoingexactlyinthedirectionitisbeingsteered.Ifthereistheslightestdifferencebetweenwherethedriverissteeringandwherethevehicleisgoing,thesystemcorrectsitspathinasplit-secondbyadjustingenginetorqueand/orapplyingthecatsleft-orright-sidebrakesasneeded.Typicalreactiontimeis40milliseconds-seventimesfasterthanthatoftheaveragehuman.Astabilitycontrolsystemsensesthedriversdesiredmotionfromthesteeringangle,theacceleratorpedalposition,andthebrakepressurewhiledeterminingthevehiclesactualmotionfromtheyawrate(vehiclerotationaboutitsverticalaxis)andlateralacceleration,explainedAntonvanZanten,projectleaderoftheRobertBoschengineeringteam.VanZantensgroupandateamofengineersfromMercedes-Benz,ledbyprojectmanagerArminMuller,developedthefirstfullyeffectivestabilitycontrolsystem,whichregulatesenginetorqueandwheelbrakepressuresusingtractioncontrolcomponentstominimizethedifferencebetweenthedesiredandactualmotion.Automotivesafetyexpertsbelievethatstabilitycontrolsystemswillreducethenumberofaccidents,oratleasttheseverityofdamage.Safetystatisticssaythatmostofthedeadlyaccidentsinwhichasinglecarspinsout(accountingforfourpercentofalldeadlycollisions)couldbeavoidedusingthenewtechnology.Theadditionalcostofthenewsystemsareontheorderoftheincreasinglypopularantilockbrake/tractioncontrolunitsnowavailableforcars.ThedebutofstabilitycontroltechnologytookplaceinEuropeontheMercedes-BenzS600coupethisspring.DevelopedjointlyduringthepastfewyearsbyRobertBoschGmbHandMercedes-BenzAG,bothofStuttgart,Germany,VehicleDynamicsControl(VDC).inBoschterminology,ortheElectronicStabilityProgram(ESP),asMercedescallsit,maintainsvehiclestabilityinmostdrivingsituations.Boschdevelopedthesystem,andMercedes-Benzintegrateditintothevehicle.Mercedesengineersusedthestate-of-the-artDaimler-Benzvirtual-realitydrivingsimulatorinBerlintoevaluatethesystemunderextremeconditions,suchasstrongcrosswinds.TheythenputthesystemthroughitspacesontheslickiceofLakeHornavannearArjeplog,Sweden.Workiscurrentlyunderwaytoadaptthetechnologytobusesandlargetrucks,toavoidjack-knifing,forexample.Stabilitycontrolsystemswillfirstappearinmid-1995onsomeEuropeanS-ClassmodelsandwillreachtheU.S.marketduringthe1996modelyear(November1995introduction).Itwillbeavailableasa$750optiononMercedesmodelswithV8engines,andthefollowingyearitwillbea$2400optiononsix-cylindercars.About$1650ofthelatterpriceisforthetractioncontrolsystem,aprerequisiteforstabilitycontrol.Boschisnotaloneindevelopingsuchasafetysystem.ITTAutomotiveofAuburnHills,Mich.,introduceditsAutomotiveStabilityManagementSystem(ASMS)inJanuaryatthe1995NorthAmericanInternationalAutoShowinDetroit."ASMSisaquantumleapintheevolutionofantilockbrakesystems,combiningthebestattributesofABSandtractioncontrolintoatotalvehicledynamicsmanagementsystem,"saidTimothyD.Leuliette,ITTAutomotivespresidentandchiefexecutiveofficer."ASMSmonitorswhatthevehiclecontrolsindicateshouldbehappening,comparesthattowhatisactuallyhappening,thenworkstocompensateforthedifference,"saidJohannesGraber,ASMSprogrammanageratITTAutomotiveEurope.ITTssystemshouldbeginappearingonvehiclesworldwideneartheendofthedecade,accordingtoTomMathues,directorofengineeringofBrake&ChassisSystemsatITTAutomotiveNorthAmerica.Companyengineersarenowadaptingthesystemtospecificcarmodelsfromsixoriginalequipmentmanufacturers.Aless-sophisticatedandless-effectiveBoschstabilitycontrolsystemalreadyappearsonthe1995750iLand850CiV-12modelsfromMunich-basedBMWAG.TheBMWDynamicStabilityControl(DSC)systemusesthesamewheel-speedsensorsastractioncontrolandstandardanti-lockbrake(ABS)systemstorecognizeconditionsthatcandestabilizeavehicleincurvesandcorners.Todetectsuchpotentiallydangerouscorneringsituations,DSCmeasuresdifferencesinrotationalspeedbetweenthetwofrontwheels.TheDSCsystemalsoaddsasensorforsteeringangle,Utilizesanexistingoneforvehiclevelocity,andintroducesitsownsoftwarecontrolelementsintheoverallantilock-brake/traction-control/stability-controlsystem.ThenewBoschandITTAutomotivestabilitycontrolsystemsbenefitfromadvancedtechnologydevelopedfortheaerospaceindustry.Justasinasupersonicfighter,theautomotivestabilitycontrolunitsuseasensor-basedcomputersystemtomediatebetweenthehumancontrollerandtheenvironment-inthiscase,theinterfacebetweentireandroad.Inaddition,thesystemisbuiltaroundagyroscopelikesensordesignusedformissileguidance.BEYONDABSANDTRACTIONCONTROLStabilitycontrolisthelogicalextensionofABSandtractioncontrol,accordingtoaSocietyofAutomotiveEngineerspaperwrittenbyvanZantenandBoschcolleaguesRainerErhardtandGeorgPfaff.WhereasABSinterveneswhenwheellockisimminentduringbraking,andtractioncontrolpreventswheelslippagewhenaccelerating,stabilitycontroloperatesindependentlyofthedriversactionsevenwhenthecarisfree-rolling.Dependingontheparticulardrivingsituation,thesystemmayactivateanindividualwheelbrakeoranycombinationofthefourandadjustenginetorque,stabilizingthecarandseverelyreducingthedangerofanuncontrolledskid.Thenewsystemscontrolthemotionnotonlyduringfullbrakingbutalsoduringpartialbraking,coasting,acceleration,andenginedragonthedrivenwheels,circumstanceswellbeyondwhatABSandtractioncontrolcanhandle.Theideabehindthethreeactivesafetysystemsisthesame:Onewheellockingorslippingsignificantlydecreasesdirectionalstabilityormakessteeringavehiclemoredifficult.Ifacarmustbrakeonalow-frictionsurface,lockingitswheelsshouldbeavoidedtomaintainstabilityandsteerability.WhereasABSandtractioncontrolpreventundesiredlongitudinalslip,stabilitycontrolreduceslossoflateralstability.Ifthelateralforcesofamovingvehiclearenolongeradequateatoneormorewheels,thevehiclemaylosestability,particularlyincurves.Whatthedriversensesas"fishtailing"isprimarilyaturningorspinningaroundthevehiclesaxis.Aseparatesensormustrecognizethisspinning,becauseunlikeABSandtractioncontrol,acarslateralmovementcannotbecalculatedfromitswheelspeeds.SPINHANDLERSThenewsystemsmeasureanytendencytowardundersteer(whenacarrespondsslowlytosteeringchanges),orover-steer(whentherearwheelstrytoswingaround).Ifacarundersteersandswervesoffcoursewhendriveninacurve,thestabilitycontrolsystemwillcorrecttheerrorbybrakingtheinner(withrespecttothecurve)rearwheel.Thisenablesthedriver,asinthecaseofABS,toapproachthelockinglimitoftheroad-tireinterfacewithoutlosingcontrolofthevehicle.Thestabilitycontrolsystemmayreducethevehiclesdrivemomentumbythrottlingbacktheengineand/orbybrakingonindividualwheels.Conversely,ifthehteralstabilizingforceontherearaxleisinsufficient,thedangerofoversteeringmayresultinrear-endbreakawayorspin-out.Here,thesystemactsasastabilizerbyapplyingtheouter-frontwheelbrake.Theinfluenceofsideslipangleonmaneuverability,theBoschresearchersexplained,showsthatthesensitivityoftheyawmomentonthevehicle,withrespecttochangesinthesteeringangle,decreasesrapidlyastheslipangleofthevehicleincreases.Oncetheslipanglegrowsbeyondacertainlimit,thedriverhasamuchhardertimerecoveringbysteering.Ondrysurfaces,maneuverabilityislostatslip-anglevalueslargerthanapproximately10degrees,andonpackedsnowatapproximately4degrees.Mostdrivershavelittleexperiencerecoveringfromskids.Theyarentawareofthecoefficientoffrictionbetweenthetiresandtheroadandhavenoideaoftheirvehicleslateralstabilitymargin.Whenthelimitofadhesionisreached,thedriverisusuallycaughtbysurpriseandveryoftenreactsinthewrongway,steeringtoomuch.Oversteering,ITTsGraberexplained,causesthecartofishtail,throwingthevehicleevenfurtheroutofcontrol.ASMSsensors,hesaid,canquicklydetectthebeginningofaskidandmomentarilyactivatethebrakesatindividualwheelstohelpreturnthevehicletoastableline.Itisimportantthatstabilitycontrolsystemsbeuser-friendlyatthelimitofadhesion-thatis,toactpredictablyinawaysimilartonormaldriving.