自动化专业毕业设计(论文)外文翻译-电子动力转向系统的研究与设计

1电气与信息学院自动化专业毕业设计（论文）外文翻译ElectonicpowersteeringsystemResearchandDesign电子动力转向系统的研究与设计2ElectronicpowersteeringsystemWhatitisElectricallypoweredsteeringusesanelectricmotortodriveeitherthepowersteeringhydraulicpumporthesteeringlinkagedirectly.Thepowersteeringfunctionisthereforeindependentofenginespeed,resultinginsignificantenergysavings.Howitworks:Conventionalpowersteeringsystemsuseanengineaccessorybelttodrivethepump,providingpressurizedfluidthatoperatesapistoninthepowersteeringgearoractuatortoassistthedriver.Inelectro-hydraulicsteering,oneelectricallypoweredsteeringconceptusesahighefficiencypumpdrivenbyanelectricmotor.Pumpspeedisregulatedbyanelectriccontrollertovarypumppressureandflow,providingsteeringeffortstailoredfordifferentdrivingsituations.Thepumpcanberunatlowspeedorshutofftoprovideenergysavingsduringstraightaheaddriving(whichismostofthetimeinmostworldmarkets).Directelectricsteeringusesanelectricmotorattachedtothesteeringrackviaagearmechanism(nopumporfluid).Avarietyofmotortypesandgeardrivesispossible.Amicroprocessorcontrolssteeringdynamicsanddrivereffort.Inputsincludevehiclespeedandsteering,wheeltorque,angularpositionandturningrate.WorkingInDetail:Asteeringsensorislocatedontheinputshaftwhereitentersthegearboxhousing.Thesteeringsensorisactuallytwosensorsinone:atorquesensorthatconvertssteeringtorqueinputanditsdirectionintovoltagesignals,andarotationsensorthatconvertstherotationspeedanddirectionintovoltagesignals.Aninterfacecircuitthatsharesthesamehousingconvertsthesignalsfromthe3torquesensorandrotationsensorintosignalsthecontrolelectronicscanprocess.Inputsfromthesteeringsensoraredigestedbyamicroprocessorcontrolunitthatalsomonitorsinputfromthevehicle'sspeedsensor.Thesensorinputsarethencomparedtodeterminehowmuchpowerassistisrequiredaccordingtoapreprogrammedforcemapinthecontrolunit'smemory.Thecontrolunitthensendsouttheappropriatecommandtothepowerunitwhichthensuppliestheelectricmotorwithcurrent.Themotorpushestheracktotherightorleftdependingonwhichwaythevoltageflows(reversingthecurrentreversesthedirectionthemotorspins).Increasingthecurrenttothemotorincreasestheamountofpowerassist.Thesystemhasthreeoperatingmodes:anormalcontrolmodeinwhichleftorrightpowerassistisprovidedinresponsetoinputfromthesteeringtorqueandrotationsensor'sinputs;areturncontrolmodewhichisusedtoassiststeeringreturnaftercompletingaturn;andadampercontrolmodethatchangeswithvehiclespeedtoimproveroadfeelanddampenkickback.Ifthesteeringwheelisturnedandheldinthefull-lockpositionandsteeringassistreachesamaximum,thecontrolunitreducescurrenttotheelectricmotortopreventanoverloadsituationthatmightdamagethemotor.Thecontrolunitisalsodesignedtoprotectthemotoragainstvoltagesurgesfromafaultyalternatororchargingproblem.Theelectronicsteeringcontrolunitiscapableofself-diagnosingfaultsbymonitoringthesystem'sinputsandoutputs,andthedrivingcurrentoftheelectricmotor.Ifaproblemoccurs,thecontrolunitturnsthesystemoffbyactuatingafail-saferelayinthepowerunit.Thiseliminatesallpowerassist,causingthesystemtorevertbacktomanualsteering.AdashEPSwarninglightisalsoilluminatedtoalertthedriver.Todiagnosetheproblem,atechnicianjumpstheterminalsontheservicecheckconnectorandreadsoutthetroublecodes.4clickheretoseeabiggerElectricpowersteeringsystemspromiseweightreduction,fuelsavingsandpackageflexibility,atnocostpenalty.Europe'shighfuelpricesandsmallervehiclesmakeafertiletestbedforelectricsteering,atechnologythatpromisesautomakersweightsavingsandfueleconomygains.Andinashorttime,electricsteeringwillmakeittotheU.S.,too.It'sjustjustamatteroftime,saysAlyBadawy,directorofresearchanddevelopmentforDelphiSaginawSteeringSystemsinSaginaw,Mich.Theissuewascostandthat'sbehindusnow.By2002hereintheU.S.thecostofelectricpowersteeringwillabsolutelybeawashoverhydraulic.Today,electricandhybrid-poweredvehicles(EV),includingToyota'sPriusandGM'sEV-1,aretheperfectdomainforelectricsteering.Butby2010,aTRWInc.internalstudyestimatesthatoneoutofeverythreecarsproducedintheworldwillbeequippedwithsomeformofelectrically-assistedsteering.TheCleveland-basedsupplierclaimsitsnewsteeringsystemscouldimprovefueleconomybyupto2mpg,whileenhancinghandling.Therearetruebottom-linebenefitsaswellforautomakersbyreducingoverallcostsanddecreasingassemblytime,sincethere'snoneedforpumps,hosesandfluids.Anotherclaimedadvantageisshorteneddevelopmenttime.Forinstance,aDelphigroupdevelopedE-TUNE,aride-and-handlingsoftwarepackagethatcanberunoffalaptopcomputer.Theycantakethatcomputerandplugitin,attachittothecontrollerandchangeallthehandlingparameters--effortlevel,returnability,damping--onthefly,Badawysays.Itusedtotakemonths.DelphihasoneOEMcustomerthatshouldstartlow-volumeproductionin'99.Electricsteeringunitsarenormallyplacedinoneofthreepositions:column-drive,pinion-driveandrack-drive.Whichsystemwillbecomethenormisstillunclear.Shortterm,OEMswillchoosethesteeringsystemthatiseasiesttointegrateintoanexistingplatform.Obviously,5greaterpotentialcomesfromdesigningthesystemintoanall-newplatform.Wehaveallthreedesignsunderconsideration,saysDr.HermanStrecker,grou