哈工大小型無人直升機電子系統(tǒng)和控制器設(shè)計英文

TheDesignofAvionicsSystemandControllerforSmallUnmannedHelicopter200712 ： 師：教申 ：工學(xué)學(xué)科所在單位：答辯日期：200712U.D.C:621.3DissertationfortheMasterDegreeofCONTROLLERFORSMALLUNMANNED Xiaofeng Prof.Zexiang Masterof ControlScienceand Dateof December,Degree-Conferring- HarbinInstituteof升飛機上。第四，直升機具有高，這將影響到飛行實驗的安全。針對以上的，本文的目標是設(shè)計一套綜合了硬件、控制算法的自主飛行控制系統(tǒng)，并將其安裝在直升機模型上。本文提出并實現(xiàn)了一種以ARM&AVR為硬件，包括系統(tǒng)傳感器電路、串口擴展電路、舵機控制電路、電源電路等硬件功能模塊，在此基礎(chǔ)上輔以傳感器、控制信號、數(shù)據(jù)和飛行控制算法等系統(tǒng)。由于是在沒有動力學(xué)模型的基礎(chǔ)上設(shè)計控制器，我們結(jié)合同類型直升機的模型設(shè)計了一套仿真。基于PID關(guān)鍵字ARMAsitsadvantagesofsmallshape,lightquality,goodflexibility,easytoachievehoveringandabletohedgehop,MiniatureUnmannedHelicopter(MUH)hasawideapplicationforegroundinbothmilitaryandcivilfield.Nowadays,theresearchofMUHattractedmanyorganizationandinstitutionbothathomeandabroad.Develoanautonomoushelicoptercontrolsystemischallengeforseveralreasons.,helicoptersareinherentlyunstableandcapableofexhibitinghighaccelerationrates.Theyarehighlysensitivetocontrolinputsandrequirehighfrequencyfeedbackwithminimumdelayforstability.Second,thedynamicsofhelicoptersareunstable,multivariable,highlycoupled,andvarywidelyacrosstheflightenvelope.Third,helicoptershavelimitedon-boardpowerandpayloadcapacity.Flightcontrolsystemsmustbecompact,efficient,andlightweightforeffectiveon-boardintegration.Finally,helicoptersareextremelydangerousandpresentmajorobstaclestosafeandcalibratedexperimentationtodesign.Consideringthechallengespresentedabove.Thegoalofthisdissertationistobuildtheautopilotsystemhardware,softwareandcontrolalgorithmandintegratewiththecommerciallyavailableradio-controlledhelicopters.Thehardwaresystem,whichemploysARMandAVRasitscorehardware,includesthecircuitrymodelsfunctioninsensordatacollection,serialcommunicationsinterfaceexpanding,motorcontrollingandpowersupply.Andseveralsoftwaremodelssuchassensordollection,controlsignalcollection,datastorageandflightcontrollingareimplementedonit.Sincethecontrollerisbuildwithoutadynamicmodel,asimulatingprogramisdeveloped.ThePIDseriescontrolsystemnotonlyacquiredgoodsimulationbutalsousedsuccessfullyinrealsystem.Theautopilotsystemperformsverywellinhoveringandlowspeed:UAV,hovering,flightcontrolsystem,ARM,

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LISTOF Goaland OverviewofUAV Relevant Dissertation HARDWAREDESIGNAND InitialMeasurementUnit GlobalPositionSystem FlightComputer Introductionof Peripheral Power SerialCommunication PhotoelectricitySeclusion OverallSystem System EMI rollrateinhelicoptercoordinatepitchrateinhelicoptercoordinateyawrateinhelicoptercoordinatehelicopterlongitudinalspeedinhelicopterhelicopterlateralspeedinhelicopterhelicopterverticalspeedinhelicopterhelicopterlongitudinalpositioninhelicopterhelicopterlateralpositioninhelicopterhelicopterverticalpositioninhelicopter Eulerangleforhelicopter Eulerangleforhelicopter Eulerangleforhelicopter rotorcraft unmannedaerial Table2-1Powerrequirementofeach Table3-1Theondutytimeofthe Figure1-1YAMAHAR-MAX Figure2-1ShuttleSCEADU Figure2-2HMR3300 Figure2-3SUPERSTARII Figure2-5AMASTERandthreeSLAVE Figure2-6RS232converting Figure2-7PhotoelectricitySeclusion Figure2-8Main Figure2-9 Figure3-2Thecharacteristics signalfor Figure3-3FastMode,Timing Figure3-4 Figure3-5Flowchart generation Figure3-7FlowcharoftheSPI Figure4-1Flightcontrolsystem Figure4-2TheX-cell Figure4-3Simulation Figure4-4HorizontalVelocityControl Figure4-5StepResponseofLateralVelocity Figure4-6StepResponseofLongitudinalVelocity Figure4-7AltitudeControl Figure4-8StepResponseofAltitude Figure4-9HeadingControl Figure4-10StepResponseofHeading Figure4-11HorizontalPositionControl Figure4-12HoveringPositioninX Figure4-13HoveringPositioninY Figure5-1PositionWhen Figure5-2BodyVelocityWhen GoalandRobotichelicoptershaveattractedagreatdealofinterestfromtheuniversity,theindustry,andthemilitaryworld.Thenumberofsituationsinwhichtheycouldbedeployedandusedsuccessfullyislimitedonlybymen'simagination.Thefollowinglistcitesafewofthepossibleusage[1,2].Searchandrescue:Robotichelicoptershavethepossibilitytoincreasedramaticallythenumberofsituationswherepeople'slivesarecurrentlysavedwiththeuseofmannedfull-scalehelicopters.Theseplatformswillbeabletosearchquicklyandsystematicallyaverylargeareaandcouldbemorereadilydeployedinweatherconditionsthatwouldnormallypreventhumanpilotedsearchandrescueandcouldbesacrificedinverydangerousconditions(fire,radioactive,andchemicalaccidentareas)tosavehumanlives.Surveillance:Robotichelicopterscouldperformavarietyofsurveillanceoperationsandreportinterestingorunusualactivity.LawEnforcement:Robotichelicopterscouldflyoverheadtoaidforcesindangeroushigh-speedchasesorcriminalsearchoperations.Inspection:RobotichelicopterscouldinspecthighvoltageelectricalLines,bridges,anddamsinremoocationsandmonitortrafficcost-effectivelyAerialMap:Robotichelicopterscouldbuildmoreaccuratetopologicalmapsthanconventionalaircraftwithsubstantialcostsavingsbyflyinginsmallerandmoreconstrainedareas.Cinematography:Robotichelicopterscouldautomaticallytracksubjectswithonboardvisionbasedobjecttrackers,andcouldflyaprescribedpathwithhighaccuracytohelpinplanningshotsandproducingspecialeffects.Inspiteoftheimportanceoftheseapplications,thereareonlyahandfulofedexamplesofrobotic-helicopterapplications.Thissituationismainlyduetothepoorflightperformancethatcanbeachievedandguaranteedunderautomaticcontrol.AutonomousflightistypicallyimplementedthroughGuidance,Navigation,andControlsystems.Thesuccessofguidanceandnavigationcomponentsreliesstronglyuponwhatlevelofperformanceisdeliverablebythecontrolcomponent.Thisisbecausetheopen-loopdynamicsofhelicoptersareonstable,multivariable,highlycoupled,non-minimumphase,andvarywidelyacrosstheflightenvelope.Thus,thelimitsintheflight-controlcomponentofsystemsjeopardizetheoverallperformance,andhavepreventedrobotic-helicopterapplicationsinreal-worldmissions.ThemaingoalofthisdissertationisthedevelopmentofanautonomoushelicoptersystemwhichemploysGPS,IMU,compassasitsprimarysourceofcontrol.Thisgoalispursuedbydevelo:ahigh-performanceandreliableavionicssystem,lowlatencyandreal-timesoftwaresystem,asimulatorandahigh-performancecontrollerforautonomoushovering.AUAVindicatesanairframethatiscapableofperforminggivenmissionsautonomouslythroughtheuseofonboardsensorandmanipulationsystems.AnytypeofaircraftmayserveasthebaseairframeforaUAVapplication.Traditionally,thefixed-winghavebeenfavoredastheplatformbecauseofmanygoodreasons:theyarcsimpleinstructureefficient,andeasytobuildandmaintain.Theautopilotdesigniseasierforfixed-wingaircraftsthanforrotary-wind:aircraftsbecausethefixed-wingaircraftshaverelativelysimple,symmetric,anddecoupleddynamics.However,rotorcraft-basedUAVshavebeendesirableforcertainapplicationswheretheuniqueflightcapabilityoftherotorcraftisrequired.Therotorcraftrantakeoffandlandwithinlimitedspace.Theycanalsohover,andcruiseatverylowspeed.ResearchofRotorcraft-basedUAVshasfinally eanactiveareaduringthelastdecadealthoughoneoftheRUAVs.OneofthedrivingforcesoftheoverdueproliferationofRUAVsmaybeattributedtothematuringtechnologiesthatbecameavailableduringthelast10years,suchasrotorcraftdynamics,controlsystemtheoryandapplication,high-accuracysmallnavigationsystemsandGPS.Whilebuildingafixed-wingaircraftthatmeetsthegivenrequirementssuchaspayloadisrelativelyeasy,buildingacustom-designedhelicopterrequirestremendous,time,andeffort.ThemarketforthehelicopterplatformforRUAVdevelopmentisverysmallandspecialized.MostoftheabovereasonscontributetothegeneralunderstandingthatRUAVsaremoreexpensiveandmoredifficulttooperatethanFUAVs.However,onlyRUAVscanperformsomeapplicationssuchaslow-speedtrackingmaneuverinlaw-enforcement,reconnaissance,andoperationswherenorunwayisavailablefortake-offandlanding.Thankstotheverticaltake-offandlandingcapability,rotorcraftscantakeoffandlando ylimitedspacesuchasashipdeck.Hover,low-speedflightandsideslipcapabilitiesmakethehelicopteraperfectvehiclefortrackingorsearchingoutgrounds.Thisversatileflightcapabilityisachievedattheexpenseofhavingcomplicatedandinherentlyunstabledynamics,towerfuel-efficiency,andslowercruisespeed.Furthermore,thehelicopterpowertrainandcontrolmechanismsareheavierandmorecomplicated.Insummary,thecharacteristicsofRUAVsarelisted:SmallspaceisrequiredforlaunchandVerticalflightmodes:verticaltake-off,landing,hover,pirouette,sideslip,low-speedcruiseMorecomplicatedmechanicalInefficientflightdynamics: umspeed,shortermissionMoreaccurateandcomplicatednavigationsensorInherentlyunstableandrelativelypoorlyknowndynamics(difficultcontrolsystemdesign)Figure1-1YAMAHAR-MAXAspointedoutabove,themainchallengesoftheRUAVapplicationcomefromtherestrictiveperformanceandtheinherentlyunstabledynamics[3,4].Therearesomeeffortstoresolvethelimitationofthecruisespeedandmissionradiuscausedbytheinefficiencyoftherotorincruisemode.Oneofthecandidatesisthetilt-rotoraircraft,whichhastwopropellersenginemodulesmountedateachendofthewingandittiltsthepropellerfromtheverticaltothehorizontaldirectiontoobtainverticallifttohorizontalthrustwhilethestubbywingtakestheresponsibilitytogeneratethelift(Figure1-2).Withthisuniquelift/thrustgenerationmechanism,thetilt-rotoraircraftsatisfiesthesamerequirementsofFUAVintermsofumcruisespeedandmissionradiuswhileittakesoffandlandsvertically.Oneofthemajordisadvantagesofthetilt-rotoraircraftistheprohibitivelyhighcostbecauseofthecomplicatedpropulsionandactuationsystemaswellastheexceptionallyhighrequirementofstructuralAnotherdrawbackofRUAVsisthesophisticatedcontrolalgorithmthanthatforacomplexvehicledynamics,whichneedsamorefixed-wingaircrafts.Theinherentlyunstableanditrequiresvelocityfeedbackaswellasattitudehelicopterdynamicsarefeedbacktostabilizeandcontrol.Velocityfeedbackneedstheaccuratevelocityestimates,whichcanbeobtainedbytheuseofaninertialnavigationsystem.Theinertialnavigationsysteminturnrequiresexternalaidssothatthevelocityandpositionestimatesdonotdivergewiththe pensatedbiasanddriftoftheinertialinstruments,i.e.,accelerometersandrategyroscope,.Anotherironyisthat,eventhoughUAVsaretypicallysmallerthanthefull-sizemannedvehicles,theyusuallyrequiresmaller,moreaccuratesensorsbecausethedemandedsensoraccuracyishigherwhenthevehicleissmaller.Forexample,theBoeing747wouldnotrequireone-meteraccuracytoguideitacrossthePacificOcean.Onthecontrary,a1mlongRUAVwouldnotbeabletoaccurayhoverwitha1m-accuracysensoraboutthegivenwaypoint.Thisobservationaloneassertsthecomplicationoftheonboardnavigationandcontrolsystemrequiredforhelicoptercontrol.Fortunay,however,manyoftheobstaclestoconstructinganautopilotsystemforRUAVsareeliminatedthankstoenablingtechnologies.Inthesensorrealm,inertialinstrumentsfabricatedbymicromachiningtechnologycanbemadesmallenoughtofitonamonolithicchipdie.TheGPSsystemprovidesthepositionestimateswithboundederroratanytimeonanylocationontheearthwhenagoodviewoftheskyisavailable.Anotherdrivingforceistheever-increasingcomputingpowerofmicroprocessors,whosespeedofinnovationissimplyamazing.Nowadays,theonboardcontrolsystemcanexecutecomplicatedguidanceandcontrolalgorithm,runninginreal-time.Anothersupportingtechnologycamefromadvancedwirelesscommunicationdevices.Theadvancesinmodeling,identificationandcontrolofthehelicopterarealsoamajorcontributingfactortotheproliferationofRUAVs.Withanaccurateunderstandingofdynamics,thecontrollerdesignandtestinghas everystraightforwardandsafe.Theavailabilityoffast,efficient,andaccuratesimulationenvironmentssuchas hasalsohelpedtospeedupthedevelopmentofOverall,thehelicopterisconsideredapromisingUAVplatformbecausethedesiredmaneuverabilitycanheachievedwithanacceptablelevelofdifficultiesintermsofcontrollerdesignandoperation.Inourresearch,thehelicopterplatformisparticularlyusefulbecauseitoffersthemaneuverabilitydesirableforoursuchasRelevantThedesignofcontrollersforrobotichelicoptershasbeen edbyWeilenmannetal.[1994],Amidietal.[1998],Mettleretal.[2000],Kooetal.[1998],Hoffmannetal.[1998],Prasadetal.[1999],Hovakimyanetal.[2001],Shimetal.[2000],andSpragueetal.[2001][5,6].Alargesetofdesigntechniques,fromclassicalcontroltoneuralbaseptivecontrol,hasbeenreported.Manyofthesecontroller-designstudieshaveusedover-simplifiedmodelsofthehelicoptersfordesignandsimulationandhaveachievedquitemodestperformance:theflightmodesarelimitedtohoverandlow-speedstraightflight,ortrackingaccuracydecreasesconsiderablyasthespeedincreasesandmaneuveringflightisattempted.Theabsenceofaccuratemodelshasalsohinderedtheunderstandingofspecificcontrolproblemsinrobotichelicopters(e.g.,largesystemdelaysandrotor/fuselagecoupling)leadingtothedesignofpoorcontrollersortheincorresessmentofcertainapproachestocontrolAfter1990,flyingRUAVsinfullsixdegrees-of-freedomandwithoutanyconstraintsorumbilicalcordsfinallybecamepossibleduetotheadventofsmall-size.high-accuracyIMUandGPS.Withthisbreak-throughtechnology,anumberofresearcheffortsinsimilartopicsofRUAVdevelopmentwerepublished[7-10].AnotherdrivingforcebehindRUAVdevelopmentwastheInternationalAerialRoboticsCompetition.Thiscompetitionhasencouragedmanyresearchgroupstobuildautonomousunmannedaerialvehiclesdesignedtoperformthegiventasks,whichrequirelow-speedorhoveringforgroundscanningandrecognition.Inthisarea,DraperLaboratoryatMIT[11],TeamHummingbirdofStanfordUniversity,theRoboticsInstituteatCarnegie-MellonUniversity,aswellasGeorgiaInstituteofTechnology[12,13],theoriginatorofthecompetition,haveparticipatedinthecompetitionsanddemonstratedtheirtechnologiesofautonomoushelicoptersystems.InEurope,UniversityofBerlinhasbeenngoutstandingworkforthe1999and2000competitions.ItisworthwhiletoreviewhowthesegroupsapproachedtheUAVdesignproblemandunderstandkeytechnologiestheyutilized.TheHumnungbirdfromStanfordwonthecompetitionin1995markingthetonebydemonstratingthefullyautonomousflightandfulfillingtherule,whichrequiredpickingupdisksononesideofatenniscourtanddropthemontheotherside.Thevehicleplatformwasahobby-purposeradio-controlledhelicopter,Excel60,whichwasheavilymodifiedtocarryatotalweightof46pounds.TheuniquefeatureofthishelicopteristhesoleuseofGPSasthenavigationsensor.TheywantedtodemonstratethatGPScouldreplacetheINS,whichisconventionallyfavoredastheprimarynavigationsensor.TheirGPSsystemconsistingofacommonoscillatorandtourseparatecarrier-phasereceiverswithfourantennaemountedatstrategicpointsthehelicopterbodyprovidestheposition,velocity,attitudeandangularinformationforvehiclecontrol.TheteamfromDraperLaboratorywonthecompetitionin1996byfulfillingthenewrule,whichrequiredtheautonomousvehicletonavigatethegivenfieldlookingforbarrelsidentifiablebythelabelsattachedtotheirtopandsideandthenreportthepositionandtypeofeachbarreltothegroundbase.Draperuseda60-classhelicopterastheirbaseplatform.Forthenavigationsystem,theytookthecanonicalapproachofINS/GPScombination.TheirnavigationsystemconsistedofaSystron-DonnerMotionPakTMIMU,aNovAGPS,adigitalcompassandanultrasonicaltimeter.TheflightcomputerwasastandardPC104system,whichis patible.Theinertialmeasurementsweresampledandprocessedbytheonboardcomputerrunningnumericalintegration,theKalmanfilteringalgorithm,andsimplePIDcontrolasthelow-levelvehiclecontrol.Thecontrolgainwasdeterminedbytuning-on-the-flywhilethesafetyofthevehicleisatthehandofaverycapablehumanpilot.ThemoraleoftheDraperapproachistodemonstratethepossibilityofbuildingRUAVsusingCOTSThewinnerintheyearof1997wasagroupfromtheRoboticsInstituteatCarnegie-MellonUniversity.TheybuilttheirRUAVonaYamahaR-50,ahelicopterdevelopedforagriculturalusesuchascrop-dustingbecauseinJapanbecauseoftheirtightregulationsontheoperationoffull-sizeaircraft.Unliketheprevioushelicopters,theirplatformhasamore-than-sufficientpayloadof20kg.Theuniquefeatureoftheirhelicopteristhevision-onlybasednavigationcapability.TheonboardDSP-basedvisionprocessorprovidesnavigationinformationsuchasposition,velocityandattitudeatanacceptabledelayontheorderof10ms.Theirvisionsystemisalsocapableofperformingtheidentificationrequiredbythesameruleasin1996.TheirresearchistheshowcaseofanadvancedvisionsystemappliedtotheaerialvehiclecontrolThedissertationisdividedintosixchapters.Chapter1introducestheapplicationandrecentresearchprogressofminiunmannedhelicopter.InChapter2,thisthesispresentsthedesignofthehardwarefunctionmodelfortheflightcontrolsystem.TheChapterinvolvesthehardwarearchitecture,processor,sensorandtheflightcomputerboarddesign.Buildingonthehardware,Chapter3addressesdesignissuesinbuildingthesoftwareforthewholesystem.Thechapterintroducesasoftwaresystemforlowlatencyandreal-timeprocess,itincludescontrolsignalcollection,sensordataprocessingandsafemode.Chapter4andChapter5presentthedesignofcontrollerandindoorandoutdoorexperimentstobuildanautonomoushelicopter.Chapter4presentsindoordesignandevaluationofanautonomoushelicoptersystem.Thechapterpresentsthedevelopmentofsimulatorwhichisemployedtoverifythehelicoptercontroller.APD-basedcontrollerisdesignedandtested.Thentheexperimentalresultsareshowed.Chapter5presentstheoutdoorflightexperimentsusingafullyintegratedautonomoushelicoptersupportingon-boardcomputerGPS,IMU,compassandreal-timecontrolsystems.Resultsofoutdoorhoveringflighttestsarepresented.Finally,Chapter6presentsconclusionsandfutureresearchdirectionsofthe HARDWAREDESIGNThesynthesisoftheavionicshardwareisatrade-offevaluationlikeanyotherdesignprocess.Anoptimaldesignsolutionissought,byfindingthebestcompromisetosatisfythedesignrequirements.ThefactorsconsideredforhardwareselectionandintegrationPerformanceofthesystemsetsthecapabilitiesofthevehicleintermsofwhichmaneuverscanbeperformed.Weightrequiresatrade-offbetweenavailablepayloadanddesiredon-boardElectromagneticinterference(EMI)canbeaseriousproblemwhenelectronicsystemsoperateinclosetoeachotherandradiotransmittersorreceivers.Propershieldingmethodsmustbeconsidered.Powerhastobedtotheavionics.Usuallybatteriesserveasasource.Itwillaffectthesystemweightandendurance.Vibrationproducedbysmallaircraftpistonenginesandrotorscandamagetheavionicsormakesensordataunusable.Hardwareintegrationissuesarephysicalaspectsasformfactorsandmountingpossibilitiesofthedesiredhardwareaswellastheelectronicinterfacesthatprovidecommunicationbetweenthecomponents.Flexibilityisbeneficialifconfigurationchangesarecommonorrequired,itincludesthepossibilitytoreplacecomponentseasily.Redundancyallowsforspecificpartsoftheavionicstofailwithoutcausinghazard.DependingonthesizeandcostofanaircraftthismaybemoreorlessMaintainabilityisafactorwheneasyaccesstotheflighthardwareisGrowthpotentialmaybeneededforfuturesystemextensionsintermsofpayload,volumeandinterfaces.Thechoiceofaircraftwasprimarilybasedonavailablemodelhelicoptersinmainland.WehavealreadyhadaSST-eagleclass90helicopterwhichispowerbygasengine.However,theoperatingcostforitistoohighandtheaccessoriesarehardtobuy.WeturntotheShuttleSCEADUEvolutionclass50helicopterwhichispowerbycarbinolengine(Figure2-1).Theoperationcostisrelativelylow.Thereplacementsforitarebyfartheeasiesttofindandtheleastexpensive.ThemainfeaturesoftheShuttleSCEADUEvolutionareshownasfollows[19].Length:Weight:Mainrotordiameter:Tailrotordiameter:Gearratio:Radiorequirement:5Figure2-1ShuttleSCEADUAvionicssystemsensorsareneededtocollectinformationonhowtheaircraftandcontrolsystemisperforming.ForabasicUAVflightcontrolavionicspackage,threemajorsensorsystemsareneeded.istheattitudeandheadingsystem.Secondisthepositionandvelocitysystem.Thirdisthealtitudesystem.Thesethreesensorsystemsareneededtomeasurethebasicstatesoftheaircraftrequiredforflightcontrol.AttitudedeterminationofaUAViscriticalifflightistobemaintained.TherearetwomajorwaystomaintainattitudeofaUAV.Themethodiswiththeuseofasensorsystemcalledanattitudeandheadingreferencesystem(AHRS).Thisdeviceisafullyintegratedsensorthatcandeterminetheattitude,magneticheading,andattituderatesofthevehicle.AnAHRSsystemislimitedinitsumtiuetotheinternaloperationofthesensor.Bothoganddigitaloutputsfromthistypeofsensorareavailable,butdigitalismorecommon.Theindustry,forthemostpart,isusingRS-232serialcommunicationsforthedigitaloutput.Thesecondattitudesystemisanaidedinertialnavigationsystem(INS).ThisattitudemeasurementsystemisveryaccurateandhashighergreaterlimitsthantheAHRS,butisdifficultandmoreexpensivetoimplement.Pastsystemsofthistypewerebuiltofseparatecomponentsandthenintegratedontheaircraftinaclosedfashion.Newertechnologyhasallowedthistypeofsensortobebuiltintoasingledevice.ThecostcomparisonbetweenanintegratedaidedINSandanAHRSisdramatic.TheaidedINSsystemissubstantiallymoreexpensivethananAHRSdevice.Weneedthe3Danglevelocityand3Dlinearacceleration.SotheIMUmustincludethe3Dgyroandthe3Daccelerometer.Consideringthepayloadofthehelicopterandtherequirementforlow-cost,wechoosetheIMU605whichisproducedbySenteraTechnologyCorporation.TheIMU605usesMEMSaccelerometersandMEMSrategyrostomeasureaccelerationsandrotationalratesaboutthethreeorthogonalaxes.TheIMU605hasameasurementrangeof+/-10gand+/-150°/sec.Customgyroandaccelerometerrangesareavailableuponrequest[20].TheIMU605comesinahybridpackagethatmeasureslessthan6cmx2.5cm3.2cm.ItspinbaseiscompatiblewithstandardDIP-40socketsandallowseasyinsertionandmountingontosystem-levelboards.TheIMU605hasoganddigitalcircuitrythattakescareofsensorsampling,signalconditioninganddompensation.ThesamplingrateandoutputrateareconfiguredbysettingtheIMU605'sregistermapviaasimplerequest-responseserialprotocol.MEMSinertialsensorsoffertheadvantageoffastresponseataverylowpower.Tosaveevenmorepoweronbattery-poweredsystems,thesensorscanbeshutdowntoputtheIMU605intostandbymode.TheAutomaticPower-CyclingModecsobeenabledtominimizethepowerconsumptionbasedonthesamplingrate.MagnetoresistivesensorHMR3300fromHoneywellisusedtomeasuretheattitudeangleinprojectiontobodyaxis.TheHMR3300includesaMEMSaccelerometerforahorizontalthree-axis,tiltcompensatedprecisioncompassforperformanceuptoa±60°tiltrange[21].CompactSolutionona1.0"by1.5"PrecisionCompass8HzContinuousUpdate-400to+850COperatingTempUARTandSPIUpto±60°ofPitchandRollAnglesUsingaMEMSFigure2-2HMR3300GlobalPositionSystemSUPERSTARⅡGPSreceiverfromNovAisusedtomeasurethe3Dvelocityandposition.TheSUPERSTARII(Figure2-3)isacompleteGPSOEMsensorthatprovides3Dnavigationonasinglecompactboardwithfulldifferentialcapability.TheSUPERSTARIIisa12-channelGPSreceiverthattracksallin-viewsalites.Itisfullyautonomoussuchthatoncepowerisapplied,theSUPERSTARIIautomaticallysearches,acquiresandtracksGPSsalites.SUPERSTARIIreceiversalsohaveSaliteBasedAugmentationSystem(SBAS)capability,forexampleWAASandEGNOS.Whenasufficientnumberofsalitesaretrackedwithvalidmeasurements,theSUPERSTARIIproducesa3-Dpositionandvelocityoutputwithanassociatedfigureofmerit(FOM).ThemainfeaturesoftheSUPERSTARIIDecodesdifferentialcorrectionsencodedintheRTCMmessageTwelvechannelcorrelatorforall-in-view liteSinglechipRFfrontSBASActive,andpassive,antennaSingle5Vpower 1GPSreceiverandnavigatoronasinglecompactTwogeneralpurposeinputOnegeneralpurposeinput/output(GPIO)Operatingtemperaturerangeof-30°Cto1PPSoutputalignedonGPSTime+2001HzmeasurementoutputalignedonGPSSupportfor62predefinedField-upgradeablefirmware(storedinFlashmemory)throughtheTTLserialCodeandCarrierPhasetrackingofL1GPSfrequencyforincreasedRetentionofsalitealmanacandephemerisdatainnon-volatilememoryforrapidtime-to-fix(TTFF)afterpowerVeryfastsignalre-acquisitionwhensignalmasking(obstructionorvehicleattitude)occursAllowsforwarm1HzPosition,VelocityandTime(PVT)FlightComputerThehelicopterisrequiredtoflyautonomously;