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DESIGNANDDEVELOPMENTOFAUTOMATICNAVIGATIONSOFTWAREFORFARMINGMACHINES1,GangLiu,*11AgriculturalUniversity*Abstract:Thenavigationsoftwareplayedanimportroleincontrolling-decisionforAutomaticNavigationsystem.
Itmainlycompleteddatareading,dataprocessinganddataoutputting.
Thedatareadingmoduleaccepteddatefromdifferentsensorsviaserialportsandextractedusefulinformation.
Thedataprocessingmoduleincludedimprovingpositioningaccuracyandcalculatingthevalueofcontrolparameter.
Thedataoutputtingmoduleshowedthenavigationstatusforusers.
Thesoftwareranwellinpractice.
Keywords:1.
INTRODUCTIONAutomaticnavigationsystemwasthebaseofprecisionfarming.
Theycouldarriveatcorrectpositionbytrackingpredefinedpathtocompletedatacollectingandseeding.
Thoughthestudyofautomaticnavigationsystemforagriculturehadalonghistory,itisatthestartingstageinChina(Q.
ZhangandH.
Qiu,2004).
Thispaperfocusedontheresearchofnavigationcontroltechniqueandpositioningmethodwhichwereimplementedinthesoftware.
automaticnavigation,mapmatching,fuzzylogiccontrol,multi-threadsYang,Y.
andLiu,G.
,2008,inIFIPInternationalFederationforInformationProcessing,Volume259;ComputerandComputingTechnologiesinAgriculture,Vol.
2;DaoliangLi;(Boston:Springer),pp.
1345–1348.
YunuoYangChina,Tel:86-10-62736741,Fax:86-10-62736746,Email:pac@cau.
edu.
cnKeyLaboratoryofModernPrecisionAgricultureSystemIntegrationResearchChinaCorrespondingauthor,Address:P.
O.
Box125,QinghuaDonglu17,Beijing,100083,P.
R.
Theprimarygoalofthisarticlewastoexploreagoodpositioningalgorithmandcontrolmethodandtodevelopaneffectivesoftwaresystemforimprovingaccuracyandstabilityofnavigationsystem.
2.
DESCRIPTIONOFAUTOMATICNAVIGATIONSYSTEMThesystemwasconstitutedbythreeparts:amaincomputer,anassistedcomputerandafarmingvehicle.
ThenavigationsoftwarerunningonthemaincomputeracceptedGPSdatafromGPSreceiverandpostureinformationfromtheassistedcomputerviaserialports.
Basedonthisdata,moreaccuratepositioncoordinatesandcontroldecisionvalueswouldbeachieved.
Thenthemaincomputercommunicatedwiththeassistedcomputertoguidethevehicle.
vehicle'speedandsteeringangle.
Theassistedcomputerreadsignalsfromsensorsandsentthemtothemaincomputer.
Itgotthedesiredsteeringangleandsentittothesteeringcontrollerwhichcoulddrivethevehicle.
3.
PRINCIPLESANDMETHODS3.
1NavigationpositioningalgorithmGPScouldaccuratelymeasuretheabsolutepositionoffarmingmachineinthefield,butitmighthaveerrorscausedbythecomplexenvironmentalconditions.
ThoughDead-reckoning(DR)algorithmcouldcalculatetherelativepositionbasedoninformationfromsensors,errorswouldbeaccumulatedduringalongtime.
ThisresearchputforwardMap-Matching(MM)theorytoimprovetheabovemethods.
Fuzzylogictheorywasdiscussedtocalculatetheirweightsaccordingtothedesiredpathinformationpositionaccuracyinpractice.
thedigitalcompasswasusedtoevaluatetheorientationofthevehicle.
TheDifferentposturesensorswereusedtogetmoreefficientinformation.
velocitysensorandanglesensorwasdesignedtodetecttravelingtheYunuoYang,GangLiuToshowthenavigationinformation,thesoftwareprovidedafriendlyinterfaceonwhichuserscoulddetecttheposition,speedanddirectionetc.
offarmingmachine.
Alltheinformationcouldbesavedforfurtheranalysis.
1346(H.
W.
Griepentrogetal.
,2006).
Themethodwashelpfulforimprovingthe3.
2NavigationcontroltechniqueThekeytechniquesofthispartweresearchingdynamicpathanddecidingcontrolvolume.
Adynamicpathsearchwasamethodtodeterminethenexttargetpointbasedonboththepathcurvatureandthevehiclespeed(ZhouZhiyan,2005).
Thepathlook-aheaddistancedeterminedbyfuzzylogictheorywasthelengthoftheprospectivepathandwasusedtolocatethepropertargetonthepath.
Thetargetpointwasusedtoevaluatethelateraldeviationandyawangle.
Thesedatawereusedtodeterminethedesiredsteeringangletoguidethevehicleaccuratelyalongthepredefinedpath.
4.
DESIGNANDDEVELOPMENTOFSOFTWARESYSTEM4.
1DesignofsoftwaresystemstructureToensureareal-timeperformance,thesystemappliedthemulti-threadsmethodondemandofmulti-tasks.
Asthethebodyofsystem,themainthreadaccomplisheddisplayingtrackingposition,operatingmap,MMmethodanddeterminingdesiredsteeringangle.
Italsowouldcommunicatewiththesemodulesandco-operatedwiththeassistedthreads.
Theassistedthreadswerepathdesigningandcommunication.
Theformeronedesignedtheoptimumpathbasedonthedatabasefollowingsomeprinciples,andthelateronecommunicatedwiththeassistedcomputertoacceptinformationandsendsignaltoeachother.
4.
2DevelopmentofsoftwaresystemThesystemwascomposedoffourmodulesillustratedbythefollowingstructure.
Thedatacommunicationmodulemainlysetportparameters,receivedsignalsfromdifferentsensorsandsentdecisioncommandtotheassistedcomputer.
Theimplementationofthisisapplicableappliedforwasapprovedhavinghigh-efficiency.
Themapmoduleincludedmapmaking,mapoperatingandmapdisplaying.
TogetanaccuratemapthisresearchfirstlygotCADmap,thenconvertedittoashapemapbyArcview3.
2systemandcollected7basepointsbyGPSreceivertoadjustmap.
Themapoperatingincludingzoomingout,zoominginandpanningwasdevelopedbyGISActiveXMapObjects2.
2.
Pathtrackinganddisplayingwasalsodesignedinthismodule.
ThepathdesigningmodulecoulddeterminethepointsattheendofthefieldandsetaproperbufferfortheCSerialPortclasstocontrolthreeports(GongJianwei,2005).
ThemethodDesignandDevelopmentofAutomaticNavigationSoftware1347farmingmachineturning.
Theprinciplesweredifferentbasedondifferentfieldshapes,vehiclestructuresandfarmersneeds.
Dijkstraalgorithmwasadoptedtofulfillpathplanningaccordingtoseveraloptimumprinciples.
AsthemostimportantpartthenavigationcontrollingmodulewasconstitutedofMM,calculatingpreviewpointanddeterminingdesiredsteeringangle.
Thesemoduleswereassociatedwiththenavigationgeographicdatabasecontainingmapinformationandmovingvehicleinformation.
MicrosoftAccess2003databasewasusedtosavedataandShapefilesmethodwasadoptedtomanagedata(LiuGuangandLiuXiaodong,2004).
5.
CONCLUSIONSomevalidationtestswereperformedontheplaygroundintheeastcampusofChinaAgriculturalUniversity.
Accordingtotheresults,thesoftwarecouldrunwellandthenavigationsystemcouldresponseintime.
ACKNOWLEDGEMENTSThispaperissupportedbythenational863projects:ControlTechniqueandProductDevelopmentofIntelligentNavigationofFarmingMachines(2006AA10A304).
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LiuGuangandLiuXiaodong,GISDevelopment—VC.
NETandMapObjects,TsinghuaUniversityPress,2004.
MechatronicsandApplications,2006.
FarmingChassis,SouthChinaAgriculturalUniversity,2005.
YunuoYang,GangLiu1348Q.
ZhangandH.
Qiu,ADynamicPathSearchAlgorithmforTractorAutomaticNavigation[J].
AmericanSocietyofAgriculturalEngineers,2004,47(2):639-646.
H.
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195-204ofChapter4