毕业设计基于单片机的超声测距仪设计外文翻译标准格式.docx

毕业设计基于单片机的超声测距仪设计外文翻译标准格式.docx

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毕业设计基于单片机的超声测距仪设计外文翻译标准格式

中英文翻译

课题：

基于单片机的超声波测距系统的设计

专业

电气工程及其自动化

学生姓名

孙旺

班级

M电气112

学号

1151402228

指导教师

吴冬春

专业系主任

顾春雷

撰写日期

2015年3月13日

电气工程学院

外文原文

Ultrasonicrangingsystemdesign

Publicationtitle:

SensorReview.Bradford:

1993.Vol.13

ABSTRACT：

Ultrasonicrangingtechnologyhaswideusingworthinmanyfields，suchastheindustriallocale，vehiclenavigationandsonarengineering．Nowithasbeenusedinlevelmeasurement，self-guidedautonomousvehicles,fieldworkrobotsautomotivenavigation，airandunderwatertargetdetection，identification，locationandsoon．Sothereisanimportantpracticingmeaningtolearntherangingtheoryandwaysdeeply.Toimprovetheprecisionoftheultrasonicrangingsysteminhand，satisfytherequestoftheengineeringpersonnelfortherangingprecision，theboundandtheusage，aportableultrasonicrangingsystembasedonthesinglechipprocessorwasdeveloped．

Keywords：

Ultrasoundr，RangingSystem，SingleChipProcessor

1.Introductive

Withthedevelopmentofscienceandtechnology,theimprovementofpeople'sstandardofliving,speedingupthedevelopmentandconstructionofthecity.urbandrainagesystemhavegreatlydevelopedtheirsituationisconstantlyimproving.However,duetohistoricalreasonsmanyunpredictablefactorsinthesynthesisofhertime,thecitydrainagesystem.Inparticulardrainagesystemoftenlagsbehindurbanconstruction.Therefore,thereareoftengoodbuildingexcavationhasbeenbuildingfacilitiestoupgradethedrainagesystemphenomenon.Itbroughttothecitysewage,anditiscleartothecitysewageanddrainageculvertinthesewagetreatmentsystem.comfortisveryimportanttopeople'slives.MobilerobotsdesignedtoclearthedrainageculvertandtheautomaticcontrolsystemFreesewageculvertclearguaranteerobot,therobotisdesignedtocleartheculvertsewagetothecore.ControlSystemisthecorecomponentofthedevelopmentofultrasonicrangefinder.Therefore,itisveryimportanttodesignagoodultrasonicrangefinder.

2.Aprincipleofultrasonicdistancemeasurement

2.1Theprincipleofpiezoelectricultrasonicgenerator

Piezoelectricultrasonicgeneratoristheuseofpiezoelectriccrystalresonatorstowork.Ultrasonicgenerator,theinternalstructureasshown,ithastwopiezoelectricchipandaresonanceplate.Whenit'stwopluspulsesignal,thefrequencyequaltotheintrinsicpiezoelectricoscillationfrequencychip,thechipwillhappenpiezoelectricresonance,andpromotethedevelopmentofplatevibrationresonance,ultrasoundisgenerated.Conversely,ifthetwoarenotinter-electrodevoltage,whentheboardreceivedultrasonicresonance,itwillbeforvibrationsuppressionofpiezoelectricchip,themechanicalenergyisconvertedtoelectricalsignals,thenitbecomestheultrasonicreceiver.

Thetraditionalwaytodeterminethemomentoftheecho'sarrivalisbasedonthresholdingthereceivedsignalwithafixedreference.Thethresholdischosenwellabovethenoiselevel,whereasthemomentofarrivalofanechoisdefinedasthefirstmomenttheechosignalsurpassesthatthreshold.Theintensityofanechoreflectingfromanobjectstronglydependsontheobject'snature,sizeanddistancefromthesensor.Further,thetimeintervalfromtheecho'sstartingpointtothemomentwhenitsurpassesthethresholdchangeswiththeintensityoftheecho.Asaconsequence,aconsiderableerrormayoccurEventwoechoeswithdifferentintensitiesarrivingexactlyatthesametimewillsurpassthethresholdatdifferentmoments.Thestrongeronewillsurpassthethresholdearlierthantheweaker,soitwillbeconsideredasbelongingtoanearerobject.

2.2Theprincipleofultrasonicdistancemeasurement

Ultrasonictransmitterinadirectiontolaunchultrasound,inthemomenttolaunchthebeginningoftimeatthesametime,thespreadofultrasoundintheair,obstaclesonhiswaytoreturnimmediately,theultrasonicreflectedwavereceivedbythereceiverimmediatelystoptheclock.Ultrasoundintheairasthepropagationvelocityof340m/s,accordingtothetimerrecordsthetimet,wecancalculatethedistancebetweenthelaunchdistancebarrier（s）,thatis:

s=340t/2

3.UltrasonicRangingSystemfortheSecondCircuitDesign

Systemischaracterizedbysingle-chipmicrocomputertocontroltheuseofultrasonictransmitterandultrasonicreceiversincethelaunchfromtimetotime,single-chipselectionof8751,economic-to-use,andthechiphas4KofROM,tofacilitateprogramming.CircuitschematicdiagramshowninFigure2.

Figure1circuitprinciplediagram

3.140kHzultrasonicpulsegeneratedwiththelaunch

RangingsystemusingtheultrasonicsensorofpiezoelectricceramicsensorsUCM40,itsoperatingvoltageofthepulsesignalis40kHz,whichbythesingle-chipimplementationofthefollowingprocedurestogenerate.

puzel:

mov14h,#12h;ultrasonicfiringcontinued200ms

here:

cplp1.0;output40kHzsquarewave

nop;

nop;

nop;

djnz14h,here;

ret

Ranginginfrontofsingle-chipterminationcircuitP1.0inputport,singlechipimplementationoftheaboveprocedure,theP1.0portina40kHzpulseoutputsignal,afteramplificationtransistorT,thedrivetolaunchthefirstultrasonicUCM40T,issued40kHzultrasonicpulse,andthecontinuedlaunchof200ms.Rangingtherightandtheleftsideofthecircuit,respectively,theninputportP1.1andP1.2,theworkingprincipleandcircuitinfrontofthesamelocation.

3.2Receptionandprocessingofultrasonic

UsedtoreceivethefirstlaunchofthefirstpairUCM40R,theultrasonicpulsemodulationsignalintoanalternatingvoltage,theop-ampamplificationIC1AandafterpolarizationIC1BtoIC2.IC2islockedloopwithaudiodecoderchipLM567,internalvoltage-controlledoscillatorcenterfrequencyoff0=1/1.1R8C3,capacitorC4determinetheirtargetbandwidth.R8-conditioninginthelaunchofthecarrierfrequencyontheLM567inputsignalisgreaterthan25mV,theoutputfromthehighjump8feetintoalow-level,asinterruptrequestsignalstothesingle-chipprocessing.

Ranginginfrontofsingle-chipterminationcircuitoutputportINT0interruptthehighestpriority,rightorleftlocationoftheoutputcircuitwithoutputgateIC3AaccessINT1portsingle-chip,whilesingle-chipP1.3andP1.4receivedinputIC3A,interruptedbytheprocesstoidentifythesourceofinquirytodealwith,interruptprioritylevelforthefirstleftrightafter.Partofthesourcecodeisasfollows:

receive1:

pushpsw

pushacc

clrex1;relatedexternalinterrupt1

jnbp1.1,right;P1.1pinto0,rangingfromrighttointerruptserviceroutinecircuit

jnbp1.2,left;P1.2pinto0,totheleftrangingcircuitinterruptserviceroutine

return:

SETBEX1;openexternalinterrupt1

popacc

poppsw

reti

right:

...;rightlocationentrancecircuitinterruptserviceroutine

AjmpReturn

left:

...;leftRangingentrancecircuitinterruptserviceroutine

AjmpReturn

3.3Thecalculationofultrasonicpropagationtime

Whenyoustartfiringatthesametimestartthesingle-chipcircuitrywithinthetimerT0,theuseoftimercountingfunctionrecordsthetimeandthelaunchofultrasonicreflectedwavereceivedtime.Whenyoureceivetheultrasonicreflectedwave,thereceivercircuitoutputsanegativejumpintheendofINT0orINT1interruptrequestgeneratesasignal,single-chipmicrocomputerinresponsetoexternalinterruptrequest,theimplementationoftheexternalinterruptservicesubroutine,readthetimedifference,calculatingthedistance.Someofitssourcecodeisasfollows:

RECEIVE0:

PUSHPSW

PUSHACC

CLREX0;relatedexternalinterrupt0

MOVR7,TH0;readthetimevalue

MOVR6,TL0

CLRC

MOVA,R6

SUBBA,#0BBH;calculatethetimedifference

MOV31H,A;storageresults

MOVA,R7

SUBBA,#3CH

MOV30H,A

SETBEX0;openexternalinterrupt0

POPACC

POPPSW

RETI

Foraflattarget,adistancemeasurementconsistsoftwophases:

acoarsemeasurementand.afinemeasurement:

Step1:

Transmissionofonepulsetraintoproduceasimpleultrasonicwave.

Step2:

Changingthegainofbothechoamplifiersaccordingtoequation,untiltheechoisdetected.

Step3:

Detectionoftheamplitudesandzero-crossingtimesofbothechoes.

Step4:

Settingthegainsofbothechoamplifierstonormalizetheoutputat,say3volts.Settingtheperiodofthenextpulsesaccordingtothe:

periodofechoes.Settingthetimewindowaccordingtothedataofstep2.

Step5:

Sendingtwopulsetrainstoproduceaninterferedwave.Testingthezero-crossingtimesandamplitudesoftheechoes.Ifphaseinversionoccursintheecho,determinetootherwisecalculatetobyinterpolationusingtheamplitudesnearthetrough.Derivetsubm1andtsubm2.

Step6:

Calculationofthedistanceyusingequation.

4.Theultrasonicrangingsystemsoftwaredesign

Softwareisdividedintotwoparts,themainprogramandinterruptserviceroutine.Completionoftheworkofthemainprogramisinitialized,eachsequenceofultrasonictransmittingandreceivingcontrol.

Interruptserviceroutinesfromtimetotimetocompletethreeoftherotationdirectionofultrasoniclaunch,themainexternalinterruptservicesubroutinetoreadthevalueofcompletiontime,distancecalculation,theresultsoftheoutputandsoon.

5.Conclusions

Requiredmeasuringrangeof30cm~200cmobjectsinsidetheplanetodoanumberofmeasurementsfoundthatthemaximumerroris0.5cm,andgoodreproducibility.Single-chipdesigncanbeseenontheultrasonicrangingsystemhasahardwarestructureissimple,reliable,smallfeaturessuchasmeasurementerror.Therefore,itcanbeusednotonlyformobi