出租车计价器中英文翻译大学毕设论文.docx

出租车计价器中英文翻译大学毕设论文.docx

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出租车计价器中英文翻译大学毕设论文

ABSTRACT

Inthispaper,amulti-channeltaximeterthatisabletodealwithmorethanonepassengersimultaneouslyisproposed.

Inordertodemonstratethetheoryofoperationoftheproposedsystem,acompletedesignforanexperimentalthree-channeltaximeter（whoseprototypehasbeenbuiltundergrantfromtheEgyptianAcademyforScientificandTechnologicalResearch）ispresented.

Systemlocation,outline,blockdiagramsaswellasdetailedcircuitdiagramsfortheexperimentaltaximeterarealsoincluded.

1.INTRODUCTION

Transportingpeopleinthemorningfromtheirhomestotheirworksandbackintheafternoonhasbecomeabigprobleminbigcitiesespeciallyinundevelopedcountries.Asapartialsolutionofthisproblem,theauthoritiesinsomecountrieshad,unofficially,leftthetaxicabdriverstocarrydifferentpassengerstodifferentplacesattheSametime.Forexample,ataxicabwithfourseatsmaycarryfourdifferentpassengerswithoutanyrelationbetweenthemexceptthattheirwayoftravellingisthesame.

Accordingly,ithasbecomeverydifficulttorelyonthepresentconventionalsingle-channeltaximetertodeterminethefarerequiredfromeachpassengerseparately.Accordingly,anunfairfinancialrelationwascreatedbetweenthetaxicabdriver,owner,passengersandthestatetaxationdepartment.

Underthesecircumstances,taxicabdriversforcethepassengerstopaymorethanwhattheyshouldpay.Insomecasespassengershadtopaydoublefaretheyshouldpay.Withthepresentconventionalsingle-channeltaximeter,taxicabownersarenotabletodeterminethedailyincomeoftheirtaxicab.

Insomecases（ataxicabwithfourseats）theymayonlygetonequarteroftheincomeofthetaxicab（collectedbythetaxicabdriver）.Fromwhichtheyshouldpaythesalaryofthetaxicabdriveraswellasthecostoffuel,minorandmajorrepairsinadditiontothecardepreciation.Asamatteroffactthepositionofthetaxicabownersisnotsobadasitseems.Ageneralagreementhasbeenreachedbetweenthetaxicabdriversandownerssuchthatthedriversshouldguaranteeafixeddailyincometotheownersaswellasthepayingforthecostoffuelaswellastheminorrepaires.Eventhoughthetaxicabdriversstillsharethelargeportionoftheincomeofthetaxicab.Alsowiththepresenceofthesingle-channeltaximeter,ithasbecomeverydifficultforthestatetaxationdepartmenttoknowtheyearlyincomeofthetaxicabandaccordinglyithasbecomeverydifficulttoestimatethetaxestobepaidbythetaxicabowners.

Inordertofacethisproblem,thestatetaxationdepartmenthadtoimposeafixedestimatedtaxesforeachseatofthetaxicabwhatevertheincomeofthetaxicab.Inthispaper,weintroducedamultichanneltaximeterthatcandealwithmorethanonepassengersimultaneously.Itshouldbepointedoutthatbythetermpassengerwemeanaonepersonoragroupofrelatedpersons.Itshouldalsobepointedoutthatourproposedmulti-channeltaximeterisnot,simply,amultidisplayreadouts.Asamatteroffactitcontainslogiccircuitsthatautomaticallychangesthefareperkillometeroftravellingdistanceorperminutesof'waitingtimeaccordingtothenumberofpassengershiringthetaxicab.Inthefollowingpartandasanexample,wewillpresentacompletedesignforathree-channeltaximeter.

Blockdiagramsaswellasdetailedcircuitdiagramsoftheexperimentalthree-channeltaximeterarealsoincluded.AprototypehasbeenbuiltundergrantfromtheEgyptianAcademyforScientificandTechnologicalResearch.

2.ANEXPERIMENTALTHREECHANNELTAXIMETER

Theoryofoperationofourexperimentaldevicetoworkasanelectronicdigitaltaximeterisbasedonthefactthathespeedometercablerotatesonerevolutionforeachmeteroftravellingdistance.

Accordingly,ifthespeedometercableiscoupledwithaspeedsensorthatgeneratesasinglepulseforeachmeteroftravellingdistance,thenourtaximetercouldbethreeupcountermodulesassociatedwithaspeedsensorunit.

However,ourexperimentaltaximeterisnotsimplyathreedisplayreadouts.Asamatteroffactitcontainslogiccircuitsthatautomaticallychangesthefareperkilometeroftravellingdistanceorperminutesofwaitingtimeaccordingtothenumberofpassengershiringthetaxicab.Thedevicemaybesplittedintotwomainparts:

Thefirstisthespeedsensorunitwhichmaybelocatedanywhereinthetaxicabsuchthataneasycouplingtothespeedometercablecanbeachieved.Thesecondunitcontainsthemainelectroniccircuit,thedisplayandcontrolpanel.Theunitshouldbelocatedsomewhereinfrontofboththedriverandthepassengers.

ApossiblecomponentslocationsisshowninFigure1.

A.SpeedSensorUnit

Themainfunctionofthisunitistosupplytrainofpulseswhosefrequencyisproportionaltotheangularrotationofthewheels.ApossibleformofaspeedsensorisshowninFigure2.

Ifmayconsistofatj.pica1permanentmagnetsinewavegeneratorwithitsoutputconnectedtoapulseshappingcircuit（twogeneralpurposesilicondiodes,1Kohmsresistorandaschmittriggerinverter）.

Inordertofindsomewaytodetectthemovementofthetaxicab,theoutputofthesinewavegeneratorisrectifiedthroughageneralpurposesilicondiodeDlthensmoothedbya1000Fcapacitor.TheoutputvoltageatterminalQisthenlimitedtothevalueof4.7voltsbyusingaIkohmsresistoraswellasazenerdiodeZD.ThelevelofthevoltageatterminalQwouldbehighwheneverthetaxicabismovingandwillbezerootherwise.Thisvoltagecanbeusedfortheautomaticswitchingfromdistancefaretotimefare.

B.MainElectronicandDisplayUnitAsuggestedshapeforthemainelectronicand

displayunitisshowninFigure3.Thecontrolanddisplaypanelcontainsall'controlsnecessaryforoperatingthetaximeteraswellasfourreadoutdisplays.Thefirstchannelwillgivethesumofmoneyrequiredfromthefirstpassenger,whilethesecondandthirdreadoutsareforthesecondandthirdpassengers,respectively.Thefourthreadoutwillgivethetotalincomeofthetaxicab.

Thecontentsofthelastreadoutshouldbenonvolatileandbeabletoberetainedevenduringparkingthetaxicab.Thechannelrotaryselectorswitchs1,2and3havefullyclockwise/anticlockwisepositions.Inthefullyanticlockwiseposition,thecounterofthecorrespondingreadoutisblanckedanddisabled.

Inthefullyclockwiseposition,thecounterisunblanked,clearedtozeroandenabledtobereadyforcountingthesumofmoneyrequiredfromthefirst,secondandthirdpassengers,respectively.

Pushingthetotalsumpushbutton4unblanksthefourthreadoutenablinganypersontoretainthereadoutcorrespondingtothetotalincome.Afterthereleaseofthepushbutton,thefourthreadoutwillbeblankedagain.Thisunitalsocontainsthemainelectroniccircuitwhichwillbefullydescribedinthefollowingsection.

3.DESCRIBTIONOFTHEMAINELECTRONICCIRCUIT

ThegeneralblockdiagramofthemainelectroniccircuitisshowninFigure4.ItconsistsoffivesubcircuitsdesignatedbythesymbolesCTIuptoCT4supportingcircuits,theseare:

ThenumberofpassengerdeticitioncircuitCTI,travellingdistancescalingcircuitCT2,waitingtimescalingcircuitCT3,circuitCT4whichgeneratesclockpulsesforthedisplaycircuit.

A.NumberofPassengersDetectionCircuitCT1Asshownfromthegeneralblockdiagram,thecircuitCTIhasthreeinputsI,2and3aswellasthreeoutputsJ,KandL.ThefunctionofthecircuitistosupplyahighlevelvoltageatterminalsJ,KorLifandonlyifone,twoorthreepassengersarehiringthetaxicab,respectively.Thetermpassenger,here,meansonepersonoragroupofrelatedpersons.Whenapassengerisgettingintothecab,wesimplyturnonafreereadoutdisplaybyturningthecorrespondingrotaryselectorswitchtoafullyclockwisedirection.

ThiswillautomaticallydisconnectthecorrespondingterminalI,2or3fromground.ThelogicalrelationbetweenvariousinputterminalsI,2and3andtheoutputterminalsJ,KandLisshowninTable1.

Asacombinationalcircuitwestartthedesignbyderivingasetofbooleanfunctions.ApossiblesimplifiedbooleanfunctionsthatgivesminimumnumberofinputstogatesmaybeobtainedfromTableI.

ApossiblelogicaldiagramthatisbasedontheabovederivedexpressionsisshowninFigure5.

Itconsistsoftwoinverters,four2-inputAND,to3-inputANDtwo3-inputORgatesB.TavellingDistanceScalingCircuitCT2

AsshownfromtheblockdiagramofFigure4,thecircuitCT2hasfourinputJ,K,LandEandoneoutputM.ThefunctionofthecircuitistosupplyasinglepulseattheoutputMforacertainnumberofpulsesgeneratedattheoutputofthespeedsensor（certainnumberofmeterstravelledbythetaxicab）,accordingtothenumberofpassengershiringthecar.AsuggestedfareperkilometeroftravellingdistanceisshownincolomntwoofTable2.thecircuit,inthiscase,shouldsupplyasinglepulseattheoutputMforevery100,125or143pulsesgeneratedattheinputterminalE

accordingtothelevelofvoltageatinputterminale3,KorL,respectively.

Ourcircuitcouldbe,asshowninFigure5,threedecadecounters,connectedasathreedigitfrequencydividerwhosedividingratios100,125and143areautomaticallyselectedbythevoltagelevelatterminalsJ,KandL,respectively.

ApossiblecircuitdiagramthatmayverifytheabovefunctionisshowninFigure6.Itconsistsofthreedecadecounterstype7490,oneBCD-todecimaldecodertype7445,three4-inputAND,one3-inputANDone2-inputANDtwo3-inputORgates.

C.TimeScalingCircuitCT3

Asshownintheblockdiagram,thetimescalingcircuitwillhavefourinputsJ,K,LandF