ABS外文文献及翻译

汽车毕业设计外文文献翻译

The6thIEEEInternationalConferenceonIntelligentDataAcquisitionandAdvancedComputingSystems:TechnologyandApplications15-17September2011,Prague,CzechRepublic

Anti-LockBrakingSystemBasedonFlexRay

Protocol

MilosOkrouhly,DenisWaraus

CzechTechnicalUniversityinPrague,FacultyofElectricalEngineering,Dept.ofMeasurement,

Technicka2,16627Prague,http://measure.feld.cvut.cz

okroumil@fel.cvut.cz,warauden@fel.cvut.cz

Abstract–Theanti-lockbrakingsystemisnowadaysapartofalmosteveryvehicle.Thissystemincreasessafetyofthepeoplesittinginthevehicleatthemomentofstoppingonaslipperyorunstableroadsurface.Thepointistoassureagoodcontrollabilityofthevehicleevenifthewheelsareinslip.Inordertoworkproperly,theanti-lockbrakingsystemneedstohaveactualinformationabouttherotationofeverysinglewheel.Andtheup-to-datenessandcertaintyofanaccurateinformationistheprimarycriterionofanappropriateperformance.Currently,theinformationaboutthefrequencyofwheelrotationisbeingtransmittedviathecurrentloop.Thissolutionneedsalotofwiring,whichmeansincreasedpurchasecosts.Thispaperdescribesamethod,wheretheinformationfromtherotationsensorsofthewheelsaretransmittedintothecontrolunitthroughtheFlexRaybus.AdditionalwirelessaccelerationsensorslocatedonthewheelareusedtoimprovetheABSperformance.

Keywords–Automotiveelectronics;Communicationnet-works;Vehiclesafety

I.INTRODUCTION

http://plexityandamountofsuchcontroldeviceshassigni cantlyrisenduringthelastdecade.Nowadays,theluxurycarscontainmorethanseventyelectroniccontrolunits(ECU)interchangingmorethantwothousandsignals.Upcomingx-by-wiresystemslikeasteer-by-wireorbrake-by-wirethusrequireareliablehigh-speedcommunicationprotocol.ForthispurposeFlexrayprotocolwasdevelopedbytheFlexRayconsorciumwhichincludesleadersoftheautomotiveindustrylikeBMW,GeneralMotoretc.TheFlexRaybuswillbeusedasabackbonenetworkforfuturevehicles.Byusingthebus,theamountofwiring-andsothecosts-canbeessentiallydecreased.

ThisresearchissupportedbythetheCzechMinistryofEduca-tion,projectnameJosefBozekResearchCenterofEngineandAu-tomotiveEngineering,grantNo.1M0568,CzechScienceFoundation(GACR),projectnameSensorsandintelligentsensorsystems,grantNo.GD102/09/H082andGrantAgencyoftheCzechTechnicalUniversityinPrague,grantNo.SGS10/207/OHK3/2T/13.

Theautomotiveanti-lockbrakingsystem(ABS)isanactivesafetechnologywhichiscurrentlythemostpopularandeffectiveone.AutomotiveABScansigni cantlyimprovethedirectionstabilityandsteeringcontrolabilitywhilebrakingandalsoreducethebrakingdistance.Duetoitsgreatcontributiontotheautomotivesafety,furtherresearchofthistechnologyisdesirable.

Themaindisadvantageofthecurrentlyusedanti-lockbrakingsystemsappearsduringbrakingonadisruptedroadway.Whenthevehicleisbrakingonthisroadwaytype,thewheelsoftenlosecontactwiththeroadsurface.Inthiscasethewheelisblockedduetopressureinthehydraulicsystemandthesituationisclassi edbytheABSsystemasaslip,sotheABSsystemisactivated.Now,theactivatedanti-lockbrakingsystemopenstheoutputvalve,sothatthepressureinthehydraulicsystemdecreasesandthewheelisthusunblocked.Duetowheelunblocking,thebrakedistanceissigni cantlyincreased.Incaseofknowninformationfromtheaccelerationsensorlocatedonthewheelitcanbeassumedthatthewheeldoesnotrotateduetodecreasedclampingforceandcanbelockedbeforeittouchestheroadsurfaceagain.Herebythebrakedistanceisdecreased.

TheaimofthispaperistoapplyanewcommunicationprotocoltocurrentABSbyreplacingtheexistingcon-nectionbetweenthesensorsandimproveABScontrolalgorithmbasedonaccelerationobtainedfromwirelessaccelerationsensor.ThenthealgorithmisevaluatedonadevelopedABSplatform.

II.FLEXRAYOVERVIEW

TheFlexRaycommunicationprotocolisatime-triggeredprotocolwherethedatatransmissionisbasedonrecurringcommunicationcyclewhichiscomposedofstaticsegment,dynamicsegment,symbolwindowandnetworkidletime.

Thestaticsegmentcomprisesa xednumberofequallysizedtimedivisionmultipleaccess(TDMA)staticslots.Thesegmentisdesignedforframeswherepredictableframedelayisde ned.Ineachstaticslotaframe(withauniqueidenti erframeID)canbetransmittedbyanode.Onceastaticslotwithauniqueidenti erisallocatedtoa

汽车毕业设计外文文献翻译

speci cnode,onlythisnodeisallowedtotransmitduringthisslotandsoprotocolensurescollisionavoidance.Inordertoensureproperslottiming,eachsinglenodeprovidessynchronizationbysynchronizationframes-framewheresynchronizationbitisset.Synchronizationisembeddedinthestandardandisbasedondifferencesbetweenrealandpredictedframereceptions.

Thedynamicsegmentemploysthe exibleTDMAapproachandisintendedforthenon-criticalandsporadicmessageswithvaryinglength.ThesymbolwindowisdesignedfortransmissionofCAS(CollisionAvoidanceSymbol),MTS(MediaAccessTestSymbol)orWUS(WakeUpSymbol).TheWUSservesonlyforwakeupofthecluster.TheCASisusedbyacoldstartnode(thenode,whichiscon guredforsetupofthecluster)toinitializethestart-upprocedure.Duringthelastpartofthecommunicationcycle(http://workidletime),eachnodecancorrecttheoffsetofitsowntimebase.Thedynamicsegmentandsymbolwindowareanoptionalpartofthecommunicationcycle.

AsminordisadvantagesoftheFlexRayprotocol,thenecessityofthestart-upprocedureandnon-recon gurabilityduringtheruntimeshouldbementioned.Foraclusterassemblyatleasttwonodesarenecessary.Thestart-upisperformedonallchannelssynchronously.Theinitializationofthestart-upprocessiscalledcold-start.Upto15ofallnodesmayinitiatestart-up.ThecoldstartattemptbeginswiththetransmissionofaCASsymbol.Onlythecoldstartnode(leadingcoldstartnode)transmittingtheCASmaytransmitframesinthe rstfourcyclesaftertheCAS.Consequently,theremainingcoldstartnodesarejoinedandafterwardsalsotherestofthenodes.Incasethereisnoactivityonabus(beforethestartupprocedure),onenodecanwakeupacluster.Theminimumprerequisiteforaclusterwakeupisthatthereceiversofallbusdriversaresuppliedwithpower.Abusdriverhastheabilitytowakeuptheothercomponentsofitsnodewhenitreceivesawakeuppattern(WUS)onitschannel.Thewakeuppatternmaynotbetransmitt …… 此处隐藏：15199字，全部文档内容请下载后查看。喜欢就下载吧 ……