外文翻译-基于单片机的汽车倒车防撞语音提示系统

外文资料BASEDONNRF24E1ANDTMC2023AUTOMOBILECOLLISIONAVOIDANCESYSTEMDEVELOPMENTANDREALIZATIONCARENGINEERINGDEPARTMENTOFINSTITUTEOFTECHNOLOGYOFMUNICHBYLORENZFERDIDADPROGRESSOFSOCIETYWITHTHEDEVELOPMENTOFTIMES,MOREANDMORECARSHAVEENTEREDORDINARYPEOPLESFAMILYTHOUGHTHEHIGHWAYTERMSISBEINGUPDATED,YETAVOIDTHECROWDEDCURRENTSITUATIONOFGETTINGONTHECAROFUNAVOIDABLEHIGHWAY,INADDITION,THESPEEDISIMPROVEDGRADUALLY,THEMALIGNANTTRAFFICACCIDENTISHAPPENINGALLTHETIME,HAVEBROUGHTTHEENORMOUSLIFEANDPROPERTYLOSSTOPEOPLEANDTHESOCIETYCARANTICOLLISIONSYSTEMWHETHERONECANSENDOUTSEEINGANDHEARINGSURVEYDEVICEOFWARNINGSIGNALINADVANCETODRIVERITINSTALL,ATCAR,CANSURVEY,ATTEMPTPEDESTRIAN,VEHICLEORBARRIERAROUNDCLOSETHEAUTOMOBILEBODYUSUALLYCANSENDOUTANDCOLLIDETHEDANGEROUSSIGNALSOONTODRIVERANDPASSENGERAHEADOFTIME,IMPELDRIVERBYPASSDRIVERTAKEEMERGENCYMEASUREPUNISHSPECIALDANGEROUSSITUATIONEVEN,AVOIDLOSSESATPRESENT,THOUGHVARIOUSCOUNTRIESSTUDY,PREVENTSYSTEMOFCOLLIDINGFROMUSUALLYCALLTHEINITIATIVESECURITYSYSTEMINTHEWORLD,BUTHOWCOULDSOLVETHETIMIDANDALERTPROBLEMBETTER,PERPLEXINGRELEVANTWORKERSALLTHETIMETHERESEARCHERINTHEWORLDSTUDIESTHROUGHALARGENUMBEROFEXPERIMENTS,HASALREADYREACHEDCOMMONUNDERSTANDING,IFWANTTOSOLVEPROBLEMDESCRIBEDABOVEEFFECTIVELY,THEANTICOLLISIONSYSTEMMUSTHAVETHEFOLLOWINGFUNCTIONS1MUSTBECAPABLEOFEXAMININGTHEANGLE,THEAZIMUTHALINFORMATIONOFTHEGOALISESSENTIALFORREMOVINGEMPTILYANDALERTLY2APTTOPRODUCEANTIINTERFERENCEPERFORMANCESTRONGCOMPLICATEDTRANSMISSIONSIGNAL,COOPERATEWITHREALTIMEHIGHEFFICIENTSIGNALDEALWITHWITHGOALMEASURINGALGORITHMS,INORDERTOREMOVEEMPTILYANDALERTLYONLYTHEABOVETWOPOINTSCOMBINETOGETHERANDGUARANTEETHESYSTEMATICDEPENDABILITYTHATTHECARDEFENDSCOLLIDINGCLOSELY1TMC2023CHIPANDTHENRF24E1CHIPCHARACTERISTICINTRODUCEDTMC2032ISONEKINDOFNEWENTIREDIGITALCORRELATIONINSTRUMENTELECTRICCIRCUIT,ITSCORRELATIONWORDLENGTHANDTHERELATEDTHRESHOLDAREPROGRAMMABLETHISCHIPISTHEMONOLITHIC64CMOSENTIRENUMERALCORRELATIONINSTRUMENTLARGESCALEINTEGRATEDCIRCUITWHICHAMERICANTRWCORPORATIONRECENTYEARSPROMOTED,ITSINTERIORHADTHREEINDEPENDENTCLOCKS8DISPLACEMENTSPOSITIONSREGISTERSSTOCHASTICDATAREGISTERA,LOCALCODEREGISTERBANDSHIELDCODEREGISTERMMOREOVERALSOHAS7REGISTERSTOUSEFORTOLOADPREPLACEDLIMIT064BETWEENWILFULLYLONGSTOCHASTICDATAANDTHELOCALCODEAFTERTHECORRELATIONOPERATION,BYTHETHREESAMITTHECUSHION7BCDCODEOUTPUT,ANDLIMITCOMPAREWITHTHEINITIALIZATIONINTHECOMPARATOR,IFTHECORRELATIVEVALUEISBIGGERTHANORISEQUALTOLIMIT,THENTHEFLAGBITBYLOWLYCHANGESHIGHBECAUSEHASUSEDTHEADVANCEDHIGHSPEEDCMOSPRODUCTIONCRAFT,THEPARALLELCORRELATIONSPEEDREACHESASHIGHASABOVE30MHZBUTWIDELYAPPLIESTOSYNCHRONIZATION,THEMATCHEDFILTERING,HARMSINTHECODEEXAMINATION,THERECORDINGANDTHEBARCODERECOGNITION,ESPECIALLYSUITSTOTHERADARSIGNALRECOGNITIONNRF24E1ISONEKINDOFOPERATINGFREQUENCYMAYACHIEVE24GHZTHEWIRELESSRADIOFREQUENCYRECEIVINGANDDISPATCHINGCHIP,THECHANNELOPERATIONTIMEISSMALLERTHAN200MUS,THEDATARATEIS1MBPSOUTSIDE,DOESNOTNEEDTOMEETTHESAWFILTER,ISGLOBALGENERALLOWCOSTRADIOFREQUENCYSYSTEMLEVELCHIPWHICHTHEPRESENTWORLDPROMOTESFORTHEFIRSTTIMETHEINTERIORINLAYSHASWITH8,051COMPATIBLEMICROPROCESSORSAND109INPUTSA/DSWITCHES,MAYBETWEENUNDERTHE19V36VVOLTAGETHESTEADYWORKTHEINTERIORALSOINLAYSHAVEIMPRESSTHEADJUSTERANDTHEVDDVOLTAGEMONITORINGDEVICEWIRELESSRECEIVINGANDDISPATCHINGPARTIALLYHASWITHTHENRF2401SIMILARFUNCTION,THISFUNCTIONSTARTSBYTHEINTERNALPARALLELMOUTHANDINTERNALSPI,EACHDUEOUTSIGNALSAYSREGARDINGTHEPROCESSORALLMAYTAKESEVERSCARRIESONTHEPROGRAMMING,ORGIVESTHEMICROPROCESSORTHROUGHTHEGPIOPORTBIOGRAPHYCHIPNRF24E1MAYREALIZETHEWIRELESSCOMMUNICATIONINWORLDPUBLICFREQUENCYBANDSCOPE2425GHZRECEIVESANDDISPATCHESTHEPARTIALPACKAGESTOINCLUDETHEFREQUENCYDIVIDER,THEAMPLIFIER,THEREGULATORANDTWORECEIVINGANDDISPATCHINGUNITSTHEOUTPUTENERGY,THEFREQUENCYBANDANDOTHERRADIOFREQUENCYPARAMETERPASSABLERADIOFREQUENCYREGISTERSCONVENIENTLYHAVEPROGRAMMEDTHEADJUSTMENTUNDERTHETRANSMISSIONPATTERN,THECURRENTCONSUMPTIONONLYHAS105MAUNDERTHERECEIVEPATTERN,THECURRENTCONSUMPTIONONLYHAS18MA,THEREFORETHEPOWERLOSSISQUITELOW2SYSTEMSSTRUCTURESENTIREWRAPINFORMATIONGATHERINGSYSTEMISCOMPOSEDBYFIVESETSOFRADIOFREQUENCIESLAUNCHESANDTHERECEIVINGDEVICE,EACHSETOFLAUNCHESANDTHERECEIVEPARTIALBASICELECTRICCIRCUITSALLARESAME,THESEFIVESETSOFTRANSMITTERRECEIVERSETALSOISCONNECTEDWITHTHEDSPCENTRALPROCESSOR,THECENTRALPROCESSORISRESPONSIBLEFORTHEDATAWHICHCALCULATESTHEMTOPASSON,MAKESTHEDECISIONMAKINGACCORDINGTOTHEACTUALSITUATIONEACHSETOFLAUNCHESANDRECEIVINGDEVICESTRUCTURELIKECHART1SHOWSFIRSTBYASTHECORERADIOFREQUENCYTRANSMISSIONCIRCUITPRODUCESTHEHIGHFREQUENCYELECTROMAGNETICWAVETAKENRF24E1,THENTHEMODULATIONSIGNALWHICHSENDSBYCORRELATIONOPERATIONCHIPTMC2032TOITCARRIESONTHEMODULATION,THUSPRODUCESWITHOTHERRADIOFREQUENCYRECEIVINGANDDISPATCHINGUNITDIFFERENTRADIOFREQUENCYSIGNALS,PREPARESFORFULLFORTHERECEIVEINORDERTOENABLETHEELECTROMAGNETICWAVESIGNALTOHAVETHEENOUGHFARPROPAGATIONDISTANCE,BUTALSONEEDSTOMODULATEAFTERTHESIGNALTOCARRYONTHEENLARGEMENT,COMPLETESTHISFUNCTIONTHEELECTRICCIRCUITISTHEMERITPUTSTHEELECTRICCIRCUITFINALLYPASSESONAIRBORNETOASUCHSIGNALWHENSENDSOUTTHEELECTROMAGNETICWAVEMEETSWHENTHEOBSTACL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ONRECERIVEWAYSISINMAYDETERMINETHEREFERENCESIGNALINTHESITUATION,TOINPUTSTHEPROFILEUSINGTHECORRELATIONINSTRUMENTORDATAMAKESTHECROSSCORRELATIONFUNCTIONWITHTHELOCALSIGNALTHEOPERATIONINTHISDESIGNTHEREFERENCESIGNALISTHELOCALCODE,THEREFOREUSESTHEMUTUALCORRELATIONRECERIVEWAYSINRADIOFREQUENCYRANGEMEASURINGSYSTEM,WHETHERTHEREISNOTONLYHASTOCARRYONTHEEXAMINATIONTOTHEECHOSIGNAL,MEANWHILEMUSTCARRIESONTHEPRECISESURVEYTOTHEECHOSIGNALANDTHETRANSMITTINGMESSAGETIMEDELAYTHISCANACCURATELYKNOWTHERADIOBROADCASTUSESTHETIME,THENFIGURESOUTBETWEENTHEOBSTACLEANDTHEVEHICLEDISTANCETHISARTICLEUTILIZESTHEADVANCEDRADIOFREQUENCYTECHNOLOGYANDTHESTABLERELIABLERELATEDALGORITHM,ENABLETHEAUTOMOBILETOHAVESTRONGLYGUARDSAGAINSTHITSTHEABILITYTHEABOVESYSTEMDESIGNPLANINTESTEDONTHECARALREADYTOREALIZEFRONT,ANDCANSOLVEINTHECERTAINDEGREETHROUGHOUTISPUZZLINGTHECORRELATIONWORKERSTWOKEYQUESTIONWHICHSTATES,NAMELYHASALREADYHADTHEKEENERTAKEABEARINGABILITYANDTHESTRONGERANTIJAMMINGABILITY,LIKETHISCANENABLETHEAUTOMOBILETOHAVESTRONGLYGUARDSAGAINSTHITSTHEABILITYALTHOUGHSO,BECAUSEINTHEMIDDLEOFTHEAUTOMOBILETRAVELPROCESSISRELATINGPERSONSSAFETY,THEREFOREITSPERFORMANCEALSOWAITSFORFURTHERENHANCES,STRENGTHENSTHEOVERALLSYSTEMTHEABSOLUTESECURITY,THENCARRIESONTHEPROMOTIONTOIT基于NRF24E1与TMC2023的汽车防撞系统的研制与实现慕尼黑理工大学汽车工程系劳伦斯费迪南德随着时代的发展及社会的进步,越来越多的汽车进入了普通人的家庭。尽管公路条件在不断改进,但仍然避免不了公路上汽车拥挤的现状,再加上车速逐渐提高,恶性交通事故无时无刻不在发生,给人们和社会带来了巨大的生命与财产损失。汽车防撞系统是一种可向司机预先发出视听告警信号的探测装置。通常它安装在汽车上,能探测企图接近车身的行人、车辆或周围障碍物能向司机及乘客提前发出即将发生撞车危险的信号,促使司机甚至撇开司机采取应急措施处理特殊险情,避免损失。当前,尽管各国都在研究防碰撞系统国际上通常称为主动安全系统,但怎样才能更好地解决虚警的问题,始终困扰着相关工作者。国际上的研究者通过大量的实验研究,已经达成共识,若想有效地解决上述问题,防撞系统必须具有如下功能1必须具备测角能力,目标的方位角信息对于去除虚警是必不可少的2易于产生抗干扰性能强的复杂发射信号,配合实时高效的信号处理和目标检测算法,用以去除虚警。只有以上两点紧密结合起来才能保证汽车防碰撞系统的可靠性。1TMC2023芯片和NRF24E1芯片特点介绍TMC2032是一种新型的全数字相关器电路,其相关字长和相关门限可编程。该芯片是美国TRW公司近年推出的单片64位CMOS全数字相关器大规模集成电路,其内部有三个独立时钟的8位移位寄存器随机数据寄存器A、本地码寄存器B和屏蔽码寄存器M另外还有一个7位寄存器用来装载预置的门限值。064之间任意长的随机数据与本地码经相关运算后,以三态缓冲的7位BCD编码输出,并与预置的门限值在比较器中比较,若相关值大于或等于门限值,则标志位由低变高。由于采用了先进的高速CMOS生产工艺,并行相关速率高达30MHZ以上。可广泛应用于同步、匹配滤波、误码检测、记录及条形码识别中,尤其适合于雷达信号的识别。NRF24E1是一种工作频率可达到24GHZ的无线射频收发芯片,通道运算时间小于200S,数据速率为1MBPS,不需要外接SAW滤波器,是目前世界首次推出的全球通用的低成本射频系统级芯片。内部嵌有与8051兼容的微处理器和10位9输入的A/D转换器,可以在19V36V之间的电压下稳定工作内部还嵌有电压调整器和VDD电压监视器。无线收发部分有与NRF2401同样的功能,该功能由内部并行口和内部SPI启动,每一个待发信号对于处理器来讲都可以作为中断进行编程,或者通过GPIO端口传送给微处理器。芯片NRF24E1可以在世界公用的频段范围2425GHZ内实现无线通讯。收发部分包含有分频器、放大器、调节器和两个收发单元。输出能量、频段和其它射频参数可通过射频寄存器方便地编程调节。在发送模式下,电流消耗只有105MA在接收模式下,电流消耗只有18MA,所以功耗相当低。2系统结构整套信息采集系统由五套射频发射与接收装置组成,每套发射与接收部分的基本电路都是一样的,这五套收发装置又与DSP中央处理器相连,中央处理器负责计算它们传过来的数据,根据实际情况做出决策。每套发射与接收装置的结构如图1所示。首先由以NRF24E1为核心的射频发射电路产生高频电磁波,然后由相关运算芯片TMC2032送来的调制信号对其进行调制,从而产生出与其它射频收发单元不同的射频信号,为接收做好充分准备。为了使电磁波信号能够有足够远的传播距离,还需要对调制后的信号进行放大,完成这个功能的电路是功放电路。最后把这样的一个信号传向空中。当发出去的电磁波遇到障碍物返回时,首先要经过相关运算芯片TMC2032对之进行识别,若是同组发射部分发出去的则收,并把这个信号进一步传给射频接收部分否则拒绝接收。然后接收部分根据电磁波在空中传播产生的相位移计算出其传播所耗的时间,再计算出障碍物与该组收发部分的距离。最后把这个距离信息送给中央处理器。中央处理单片机要同时对五组射频收发单元传过来的距离信息做出计算,得出所测的障碍物与车的空间方位。到此,障碍物的信息采集工作基本完成,剩下的就是把这个综合信息再传给更高级的中央处理器,让其做出最后决策。3收发单元的布置方案及计算原理汽车在行驶的过程当中,对于前方的障碍物,要能够判断其相对于汽车的空间立体方位才能把前后、左右、上下的障碍物避开而后面的障碍物,则只需判断出其与汽车的前后及左右距离即可。所以采取在车前面安装三个射频收发系统,并且三套收发系统彼此之间呈垂直于水平面的三角形分布。在车后面则安装两套射频收发系统,呈水平分布。整个收发系统的安装如图2所示。下面给出用射频收发系统计算障碍物距离的简单过程。障碍物距离计算示意图如图3所示