A-new-type-of-auto-tracking-intelligent-vehicle--张

Anewtypeofauto-trackingintelligentvehicleZhiqiangZhangSchoolofElectricalEngineering,ZhengzhouUniversity,Zhengzhou45000Abstract—Thispaperpresentsadesignschemefornewtypeofauto-trackingintelligentvehicle.Thesystemcomposesahostcomputerandaslavemachine,amongthemwirelessserialcommunicationisadopted.Withtheslavepartadoptsmicro-mechanicalaccelerometersensorasthecore,real-timemoni-toringofthemotionstateofthehumanbody,theembeddedmicroprocessorconvertsaccelerationsignalafterintegralandnumericalcomputationintovelocityanddisplacementsignalwhichwillbesentbytheBluetoothmoduletothehost.Afterpreprocessingthesignal,thehostmovestheintelligentvehicle;realizethetrackofhumanmovement.Theapplicationoftheexperimentalprototypeshowsthatithasadvantagesoffasttrack-ingspeed,stableperformance,andlowcost,lowconsumption,simpleoperation,whichcanbeappliedtointelligenttoys,trafficnavigationandotherfields..I.INTRODUCTIONWiththerapiddevelopmentofeconomyofChina,theconsumersoftoymarketaregrowingsharply.Andwiththecontinuousexpansionofembeddedmicroprocessors,sensorsandtheapplicationsurfacesofrobotics,Productsoftoyshavealreadyputtedmorefocusontechnologyandinnovation.Manynewintelligenttoyshaveappeared.Thedemandforhigh-techentertainmentproductswillincreasesharply.Thispaperpresentsadesignschemefornewtypeofauto-trackingintelligentvehicle.Itusesembeddedmicroprocessorsandmicro-accelerometerofmicro-machiningtechnologyasthecoredevice.Itshowslowpowerconsumption,smartcompactandinteresting.Thedesignandtrackingprinciplecanalsobeusedintheautomotive,transportationandotherfields.Ithasbroadapplicationprospects.II.MOTIONMODELInourdailylives,themovementoftargethasalotofrandomness.Butforthetrackingsystem,wecanachieveitsfunctionbysimulatingthehorizontalmovementcharacteristicsoftheuser.Sothedesigncanbeapproximatelyconsideredthecomplexplanemotionofbody’smovement.A.MotionModelWhenthecarinmotion,thedirectionandspeedofmove-mentarecontrolledbyfourmotors.Whenthespeedisnegative,themotorsarereversal,andotherwise,themotorsareforward.Themovementofthecariscontrolledbythedifferencespeedbetweenthemotor.Theradius,thatistheturningofthecar,canbecalculatedaccordingtothekinemat-icsknowledge,inordertodeterminethepositionofthecaratthenexttime.Kinematicequationsofthesmartcarareshownbelow:R=L(VM+Vm)2(VMVm)!=VMR+L2v=!R=!TVMtakesthelagerabsolutevalueofspeedbetweenleftandrightwheel.Vmtakesthesmallerabsolutevalueofspeedbetweenleftandrightwheel.Ristheradiusoftheturningcar.!istheangularvelocityofthecar.Listheleftandrightdrivecenterdistance,isthelinearspeedofthecar,istheangleoftheturningunittimeintervalTwithinthecar.KinematicmodelofthecarisshowninFigure1.Figure1.KinematicmodelofthecarSettheinitialpositionofthecaras(x0;y0).TheinitialX-axisdeflectionangleis0.Afterunitoftime,thelocationofthecaris(xt;yt).Andithasthefollowingrelationship:xt=2Rsin2cos0+2+x0yt=2Rsin2sin0+2+y0B.TheoverallstructureofthecarThesystemusesthecurrentapplicationofanextremelywiderangeofmicromechanicalaccelerationsensorasthepri-marysensor.Inordertoachievethepositionofthetarget,weuseBluetoothasacommunicationmedium.Duetothecurrentlarge-scalepopularityofAndroidmobilephonesystem,theslaveengineofthesystemisreplacedbysmartphonesthathavetheintegratingaccelerationsensor.TheoverallstructureofthesystemisshowninFigure2.Thesystemincludestwopartsthatarethemainengineandtheslaveryengine.Boththemainengineandslaveryengineareusedin51-compatiblekernelSTCmicrocontrollerascontroller.Throughthewheelrotationspeedmonitoringmodule,themainengineachievesprecisecontrolofmovementofthecar.Theslaveryengineismadeofacontroller,anaccelerationsensormoduleandBluetoothwirelesscommu-nicationmodulesandothercomponents.Whenthecarmoves,theaccelerationsensorcapturestheaccelerationofX-axisandY-axisinreal-time.Andtheaccelerationisgiventothecontroller.Byintegratingcomputing,thecontrollercangetthespeedofthecar.ThenthecontrollerputthedateoutbyBluetoothwirelessserialmodule.TheBluetoothreceivermoduleofthemainenginereceivesthetwospeedsofanises.AndMCUcontrolsthemovementofthecar.Figure2.TheoverallstructureofthesystemIII.THEDESIGNOFSYSTEMATICCIRCUITA.ThecircuitoftheslaveryengineThecircuitoftheslaveryengineisshowninFigure3.Elementsaredescribedbelow.1)Accelerationsensor:ADXL345isa3-axisaccelerometerthatissmall,thin,andultra-low-power.Andithashighresolution.Therangeofmeasuringisupto´s16g.Thedigitaloutputdatais16twoscomplementformats.ItcanbeaccessedviatheSPI(3-wiresor4-wires)orI2Cdigitalinterface.ItcanmeasuretheFigure3.Thecircuitoftheslaveryenginestaticaccelerationofgravityintilt-sensingapplications.Itcanalsomeasurethemotionorshockduetodynamicacceleration.Itsresolutionisupto3.9mg/LSB.Andthepowerconsumptionisverylow,aslowas23uAinmeasurementmode.Whenitisused,theaccelerationsensorisrequiredtoachieveastrictlyhorizontalrelia-bilityofthedata.2)Bluetoothwirelesscommunicationmodules:ZK-07Bluetoothcommunicationmodulecantransparentlytransmitdataofanysize.Alsoithassmallsize,widevoltageandothercharacteristics.Theexternalinterfacemoduleusestransparentdatatransmission,itcanadapttos