外文文献和翻译Word文档下载推荐.docx
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学号:
201207013120
院系:
机械与控制工程学院
专业年级:
2012级自动化专业
指导教师:
张晓玲
2016年4月20日
DesignoftrafficlightcontrolsystembasedonMCGS
Abstract:
Onekindoftrafficlightcontrolsystemusingprogrammablelogiccontroller(PLC),viasoftwarecontroltrafficlightsrunautomatically.Inthesystem,theoriginallineistheprograminsteadoftherelay,programmablelogiccontroller(PLC)systemhardwareandsoftwareresourcestobefairuse.NormaloperationandemergencytransportforadetaileddescriptionandfromtheEastandWestemergenciescanbemutuallylinked.Trafficsignalsystemsandtwoseven-segmentdigitaldisplayinthecountdownorder;
alsodiscussedindetailthewiringofthehardwareandPLCladder.TrafficlightsatthecrossroadsoftheremotemonitoringsystemdesignconfigurationsoftwareMCGS,real-timemonitoringoftrafficlights,greatlyimprovingthereliabilityofdatatransmission.Atthesametime,wecanconfigurethetrafficlightstochangethestatusofphotographs。
Keywords:
switchingpower,supplyprotection,circuitsystemdesign
Signalcontrolisanecessarymeasuretomaintainthequalityandsafetyoftrafficcirculation。
Furtherdevelopmentofpresentsignalcontrolhasgreatpotentialtoreducetraveltimes,vehicleandaccidentcosts,andvehicleemissions.Thedevelopmentofdetectionandcomputertechnologyhaschangedtrafficsignalcontrolfromfixed—timeopen-loopregulationtoadaptivefeedbackcontrol.Presentadaptivecontrolmethods,liketheBritishMOVA,SwedishSOS(isolatedsignals)andBritishSCOOT(area-widecontrol),usemathematicaloptimizationandsimulationtechniquestoadjustthesignaltimingtotheobservedfluctuationsoftrafficflowinrealtime.Theoptimizationisdonebychangingthegreentimeandcyclelengthsofthesignals。
Inarea-widecontroltheoffsetsbetweenintersectionsarealsochanged。
Severalmethodshavebeendevelopedfordeterminingtheoptimalcyclelengthandtheminimumdelayatanintersectionbut,basedonuncertaintyandrigidnatureoftrafficsignalcontrol,theglobaloptimumisnotpossibletofindout.
Inadaptivetrafficsignalcontroltheincreaseinflexibilityincreasesthenumberofoverlappinggreenphasesinthecycle,thusmakingthemathematicaloptimizationverycomplicatedanddifficult。
Forthatreason,theadaptivesignalcontrolinmostcasesisnotbasedonpreciseoptimizationbutonthegreenextensionprinciple.Inpractice,uniformityistheprinciplefollowedinsignalcontrolfortrafficsafetyreasons.Thissetslimitationstothecycletimeandphasearrangements。
Hence,trafficsignalcontrolinpracticearebasedontailor-madesolutionsandadjustmentsmadebythetrafficplanners.Themodernprogrammablesignalcontrollerswithagreatnumberofadjustableparametersarewellsuitedtothisprocess.Forgoodresults,anexperiencedplannerandfine—tuninginthefieldisneeded。
Fuzzycontrolhasproventobesuccessfulinproblemswhereexactmathematicalmodellingishardorimpossiblebutanexperiencedhumancancontroltheprocessoperator.Thus,trafficsignalcontrolinparticularisasuitabletaskforfuzzycontrol.Indeed,oneoftheoldestexamplesofthepotentialsoffuzzycontrolisasimulationoftrafficsignalcontrolinaninter-sectionoftwoone—waystreets。
Eveninthisverysimplecasethefuzzycontrolwasatleastasgoodasthetraditionaladaptivecontrol.Ingeneral,fuzzycontrolisfoundtobesuperiorincomplexproblemswithmultiobjectivedecisions。
Intrafficsignalcontrolseveraltrafficflowscompetefromthesametimeandspace,anddifferentprioritiesareoftensettodifferenttrafficflowsorvehiclegroups.Inaddition,theoptimizationincludesseveralsimultaneouscriteria,liketheaverageandmaximumvehicleandpedestriandelays,maximumqueuelengthsandpercentageofstoppedvehicles。
So,itisverylikelythatfuzzycontrolisverycompetitiveincomplicatedrealintersectionswheretheuseoftraditionaloptimizationmethodsisproblematic.
Fuzzylogichasbeenintroducedandsuccessfullyappliedtoawiderangeofautomaticcontroltasks.Themainbenefitoffuzzylogicistheopportunitytomodeltheambiguityandtheuncertaintyofdecision-making.Moreover,fuzzylogichastheabilitytocomprehendlinguisticinstructionsandtogeneratecontrolstrategiesbasedonprioricommunication.Thepointinutilizingfuzzylogicincontroltheoryistomodelcontrolbasedonhumanexpertknowledge,ratherthantomodeltheprocessitself。
Indeed,fuzzycontrolhasproventobesuccessfulinproblemswhereexactmathematicalmodellingishardorimpossiblebutanexperiencedhumanoperatorcancontrolprocess.Ingeneral,fuzzycontrolisfoundtobesuperiorincomplexproblemswithmulti—objectivedecisions。
Atpresent,thereisamultitudeofinferencesystemsbasedonfuzzytechnique。
Mostofthem,however,sufferill—definedfoundations;
eveniftheyaremostlyperformingbetterthatclassicalmathematicalmethod,theystillcontainblackboxes,e。
g。
defuzzification,whichareverydifficulttojustifymathematicallyorlogically。
Forexample,fuzzyIF—THENrules,whichareinthecoreoffuzzyinferencesystems,areoftenreportedtobegeneralizationsofclassicalModusPonensruleofinference,butliterallythisnotthecase;
therelationbetweentheserulesandanyknownmany—valuedlogiciscomplicatedandartificial。
Moreover,theperformanceofanexpertsystemshouldbeequivalenttothatofhumanexpert:
itshouldgivethesameresultsthattheexpertgives,butwarnwhenthecontrolsituationissovaguethatanexpertisnotsureabouttherightaction.Theexistingfuzzyexpertsystemsveryseldomfulfilthislattercondition.
1.Introduction
Withthesocialdevelopmentandprogress,trafficflowbecomesincreasinglyimportant.Ontheonehand,toomanycrossroads,moreandmorevehicles,whicharecausingserioustrafficcongestion.Ontheotherhand,inthelimitedtimeitisnecessarytomaintainthevehicleandpedestrianfastandsafe.Therefore,onekindoftrafficlightcontrolsystemdesign,canbeusedtodisplaytimecountdown,withcomputercontrolledreal—timedata。
Inaddition,theconfigurationtechnologyforreal-timeimagesthatreflectthetrafficlights,understandthehistoricalcrossroadsofworktogettrafficlightsvisualization。
Thesystemconsistsofhostcomputerandalowcomputer。
MCGSconfigurationisinstalledinthehostcomputerislowerbythePLCcontrolsystem。
NormaltrafficsignaltimingdiagramshowninFigure1。
Buttherearesomeurgentmatters,forexample.Thereareanumberofambulancestotransportpatientstothehospitalortodealwithanumberoffireenginesandfire.Fireenginesandambulancesrushedtotakeprecedenceoverothertrafficscene.Accordingtourbantrafficcontrolsystem,undernormalcircumstances,twocontrolmethodsandurgencytrafficcontrolfactorsintoaccount.Thisprocesscanshow14segmentencoder.U。
S。
trafficlightsinstantrecordofthemonitoringprocess.
Emergencycontrolsignalstocontroltrafficemergencyswitch。
Ifthereisnoemergencylightsallwork,butwhenanemergencyopen。
Inthiscase,thecarisurgentprioritypass.Oncetheemergencyvehiclepasses,emergencyswitchoffimmediately。
Thegreenlightinthesamedirectionofthevehiclequicklyflashesthreetimes,followedbythenormaloperation。
Ifyouwerefromthenorth-southandeast—westtwoemergencyvehicles,trafficcontrolsystemscanrespondquicklycameearly,andthenanother。
2.TrafficControlSystemDesign
A。
Hardwaredesign
CP1HseriesPLCascontroller,displaytheprocedureshouldstopwhenthetimeseriesofabnormalsystemoperation,thetimewillnotbedisplayed。
Whentheemergencyproceduresarecompletedtimeseries,countdowndisplayprogramshouldbereset.At220VACsystemisusedtocontroltrafficlights,24VDCcontrolsegmentencoder,Figure2showstheschemeEasterntimedisplay.CP1Hseriesprogrammablelogiccontroller(PLC)isasimplecontroller,whichconsistsof24inputsandsixteenoutputs.BecausetheoutputtotwentyInthissystem,anI/Omodulemustbeextended.CircuitisshowninFigure2。
B.ControlProgramDesign
Sixtimersandtwospecialnormalopenpulseisusedinthissystem,thegreenlightflashesforallnorth—southandeast—timerandaspecialpulse;
eightkindsofinterlockinginternalrelayisusedtoimplementtheurgencyandtransmitpulsetwodirectionstoPLC,showninthefigure。
TwoSDECinstructionsareusedtodisplaythecountdowndisplaythecorrespondinglight.Asanimportantpartofthecountdowndisplayprogram,eastandwestofthegreenlightreflectedintheview4intheseprogramsdownloadedtotheprogrammablelogiccontroller(PLC),allthetrafficlightsrunningaccuracy,urgency,andthingscanbeinterlockedfromnorthtosouthstrictly,allthelightscanbesetbacktotheurgencyofpassingstate。
Therefore,thesecontrolprogramiscorrect,simple.
C。
MonitoringSystem
Computersystemhastwomainfunctions:
anoutputsignalacquisitionanddisplayreal-timestatusoftheprogrammablelogiccontroller(PLC)tocontroltrafficlights,trafficlights.Anothernotificationrobotstatusandhistoryofthestatereal—timecurvebyexaminingthehistoryandalarmwindow。
ThismonitoringsystemdesignandconfigurationsoftwareMCGSconfigurationiseasy。
Theserialcommunicationisimplementedasfollows。
Datainspectionmethods:
doubleended
SerialCommunicationsNumber:
COM0ended
Theminimumsamplingperiod:
200ms
ProgrammableLogicController(PLC)Theparametersaredefinedasfollows:
Theminimumsamplingperiodofthebasicproperties:
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