Upload
renny-amalia-pratiwi
View
234
Download
2
Embed Size (px)
Citation preview
8/12/2019 Autonomous Landing UAV
1/58
8/12/2019 Autonomous Landing UAV
2/58
Autonomous Landing UAV
Session 2008/2009
I | P a g e
Summary
ThisthesispresentsthesystemarchitectureforlandinganUnmannedAerialVehicle
(UAV)fromahoveringpositionwithouttheinterventionofahumanoperator.
Throughtheuseoffeedbackinformationfromaheightsensor,theUAVis
commandedtoperformcontrolleddescentwiththedesiredlandingparametersby
implementationoftheflightcontrollaws.
Theplantmodelofthesystemwasdeterminedinordertosimulatethesystem
usingMatlab,Simulink.Throughtheuseofsimulations,thevariablesofthe
controllersarevariedtodeterminethemostappropriategainsthatwillresultinthe
mostpreferredlandingprofile.
Inthis
project,
the
vertical
component
which
controls
the
climb
and
descends
of
the
platformwasisolatedfromtheroll,pitchandyawthroughtheuseofajig.Therefore,
thiscurrentprojectonlycommandstheheightoftheplatformbutcanbefully
expandedtocommandtheroll,pitchandyawwithadditionsensorssuchasrate
gyro.
8/12/2019 Autonomous Landing UAV
3/58
Autonomous Landing UAV
Session 2008/2009
II | P a g e
Acknowledgement
Theauthorwouldliketoexpresshisappreciationtotheprojectsupervisor,
AssociateProfessorGerardLengSiewBing,fortheopportunitytoworkonthis
project,aswellasforhispatientguidanceinthevariousaspectsoftheproject.
Theauthorwouldalsoliketoextendhissincereappreciationtothefollowingpeople
fortheirassistanceduringthecourseofthisproject:
1. MrMuhamadAzfarbinRamli,GraduatestudentoftheCOSYlab,forhiskindassistancetothevariousproblemsthatwasencounteredduringthecourse
ofthisproject.
2. MsAmyChee,MsPriscillaLee,MrChengKokSengandMrAhmadBinKasa,StaffoftheDynamics&Vibrationlab,fortheirhelpandsupportwith
necessary
equipments.
3. MrRonaldTanHanRongforhissupportandassistanceduringtheconstructionphaseofthecoandereffectflyingsaucer.
8/12/2019 Autonomous Landing UAV
4/58
Autonomous Landing UAV
Session 2008/2009
III | P a g e
ContentsSummary .................................................................................................................................... I
Acknowledgement .................................................................................................................... II
ListofFigures ............................................................................................................................V
ListofTables ............................................................................................................................ VI
ListofSymbols ........................................................................................................................ VII
1. Introduction...................................................................................................................... 1
1.1. Objective ................................................................................................................... 1
1.2. Historicalbackground ............................................................................................... 1
2.Theory............................................................................................................................... 3
2.1. HelicopterAerodynamics.......................................................................................... 3
2.2. PIDSystem ................................................................................................................ 4
3. HardwareandSetup........................................................................................................ 5
3.1. UAVPlatform ............................................................................................................ 5
3.1.1. CoanderEffectFlyingsaucer............................................................................. 5
3.1.2. DraganflyerTiV................................................................................................. 6
3.2. Testbedconstruction ............................................................................................... 7
3.3. Sensorwithmounting............................................................................................... 8
3.4. Microcontroller:BasicStamp.................................................................................... 8
3.5. Communication......................................................................................................... 9
3.6. Problemsencountered ........................................................................................... 10
3.6.1. Pausewidth..................................................................................................... 10
3.6.2. Trimmedsignal................................................................................................ 10
3.6.3. LagtimebetweenPulseTrain......................................................................... 10
3.7.
Programmingalgorithm.......................................................................................... 13
4. Experimentsconducted................................................................................................. 14
4.1. OperationoftheFutabaRFtransmitter ................................................................. 14
4.2. ExperimentsonDraganflyer ................................................................................... 15
5. ResultsandDiscussions.................................................................................................. 18
8/12/2019 Autonomous Landing UAV
5/58
Autonomous Landing UAV
Session 2008/2009
IV | P a g e
5.1. Testingandcalibrationofultrasonicsensor ........................................................... 18
5.2. Determinerelationshipbetweenthrottleandthrust............................................. 19
5.3. MeasurementofPWMsignalfromradiotransmitter............................................ 19
5.4.
Relationshipbetween
helicopter
controls
and
pulse
width ................................... 21
5.5. Determinesystemplantmodel .............................................................................. 22
5.6. SimulationsusingMatlab,Simulink ........................................................................ 23
5.6.1. ZieglerNicholsmethod ................................................................................... 23
5.6.2. ProportionalDerivativecontrol:TrialandErrormethod ............................... 23
5.7. Flighttest ................................................................................................................ 24
5.7.1. Flight1:Scheduledproportionalcontrol ........................................................ 24
5.7.2. Flight2:Throttlereductionof20% ................................................................. 25
5.7.3. Flight3:ProportionalDerivativecontrol ........................................................ 25
5.7.4. Flight4:Hovertosetpoint ............................................................................. 26
5.8. Analysiswithsimulatedplot ................................................................................... 27
5.8.1. Comparingsimulationandactualplot............................................................ 27
5.8.2. Rootlocusanalysis.......................................................................................... 27
6. Conclusions..................................................................................................................... 30
7. RecommendationsforFurtherWork............................................................................ 31
7.1.
Integratingcontroller
for
Roll,
Pitch
and
Yaw......................................................... 31
7.2. Camerasystemtolocatelandingzone ................................................................... 31
References .............................................................................................................................. 32
AppendixI. FiguresandTables ...................................................................................... 34
AppendixII. Fourworkingstatesofarotorinaxialflight ............................................. 37
AppendixIII. Coandereffect ............................................................................................ 39
AppendixIV. ZieglerNicholstuningmethod................................................................... 40
AppendixV. CoanderEffectflyingsaucerexperiment .................................................. 41
AppendixVI. Autonomouslandingprogram(Basic) ....................................................... 45
8/12/2019 Autonomous Landing UAV
6/58
Autonomous Landing UAV
Session 2008/2009
V | P a g e
ListofFigures
Figure1:(A)WakebehaviourOGE/IGE;(B)ThrustratioVsDistance ..........................3
Figure2:
Block
Diagram
of
PID
Control
system ............................................................ 4
Figure3:ConstructionoftheCoanderEffectUAV ....................................................... 5
Figure4:FlightcontroloperationoftheDraganflyerVTi............................................6
Figure5:ConstructedTestbed.....................................................................................8
Figure6:UltrasonicdistancesensorattachedtoUAV .................................................8
Figure7:Communicationofcontrolsystem.................................................................9
Figure8:Lagtimebetweenpulsetrain ......................................................................11
Figure9:
New
communication
system........................................................................12
Figure10:Flowchartofautonomouslandingsystem................................................13
Figure11:ExperimentalsetuptomeasurePWMsignal.............................................14
Figure12:Experimentalsetuptomeasuregeneratedthrust ....................................15
Figure13:SystemplantmodelledinSimulink............................................................16
Figure14:(A)Ultrasonicsensorresults;(B)Percentageerrorbelow40cm ..............18
Figure15:PlotofThrustVsThrottle...........................................................................19
Figure16:
PWM
Signals
from
Futaba
transmitter ...................................................... 19
Figure17:Sevenchannelsfromsinglepulsetrain .....................................................21
Figure18:(a)PlotofThrottleVsPulsewidth;(b)PlotofThrustVsPulsewidth ....... 21
Figure19:PlotsofRateofdescentVsPulsout ...........................................................22
Figure20:Systemsplantmodel.................................................................................23
Figure21:SimulationsusingZieglerNicholsmethod.................................................23
Figure22:SimulationsusingPDcontrol ..................................................................... 24
Figure23:
Results
using
scheduled
proportional
control ........................................... 24
Figure24:Resultsusingthrottlereductionmethod...................................................25
Figure25:ResultsusingPDcontrol:(a)Kp:1.0/Kd:1.0;(b)Kp:3.0/Kd:1.0..................25
Figure26:HoveringtosetpointusingPDcontrol......................................................26
8/12/2019 Autonomous Landing UAV
7/58
Autonomous Landing UAV
Session 2008/2009
VI | P a g e
Figure27:Comparisonbetweensimulatedandactualplot.......................................27
Figure28:Rootlocusplot ........................................................................................... 28
Figure29:ModelofCoandereffectUAVusingSolidworks........................................34
Figure30:
Test
bed
model
in
Solidworks .................................................................... 34
Figure31:PinOutdiagramofRFtransmitter,FutabaSkysport6T6YG ..................... 35
Figure32:Modifiedwiringintotrainerport...............................................................35
Figure33:Futabatransmittercontrolsdiagram.........................................................35
Figure34:Serialcommunicationwithflowcontrol....................................................36
Figure35:DescriptionofPulsewidthVsChannel ...................................................... 36
Figure36:FlowvisualizationatvariousdescentvelocitiesusingShadowgraphy......37
Figure37:Flowacrossalimitingsurface.................................................................... 39
Figure38:ModificationtoPlatform ...........................................................................41
Figure39:J.Naudinsexperimentalsetup..................................................................42
Figure40:Naudinsresult ........................................................................................... 42
Figure41:Experimentalsetupforairspeedmeasurement........................................43
Figure42:Variablesofexperiment.............................................................................43
ListofTables
Table1:ZieglerNicholstuningchart ..........................................................................40
Table
2:
Airspeed
test
results......................................................................................44
8/12/2019 Autonomous Landing UAV
8/58
Autonomous Landing UAV
Session 2008/2009
VII | P a g e
ListofSymbols
h Altitude,displacementfromgroundAltituderatechange
e Error
or Proportionalgain
Integralgain
Derivativegain
Integralcontrollerscaler
Derivativecontrollerscaler
Ultimateperiod
Controllertransferfunction
Open
loop
transfer
function
Closedlooptransferfunction
Risetime
Peaktime
Settlingtime
Maximumovershoot
8/12/2019 Autonomous Landing UAV
9/58
Introduction
Session 2008/2009
1 | P a g e
1. Introduction1.1.Objective
ThisprojectaimstodevelopanautonomouslandingsystemthatwillenableaUAV
tolandautonomouslywithouttheinterferenceofahumanoperator.Thescopeof
thisprojectwaslimitedtothealtitudecontrolonly,withouttheinterventionofthe
Roll,PitchandYawmotion.However,thedevelopedconceptsandcontrollawscan
alsobefurtherextendedtoencompassRoll,PitchandYawcontrolwithadditional
sensorssuch
as
the
rate
gyro
or
the
tilt
sensor.
Someotherobjectivesaretheselectionandtestingofasuitablealtitudesensor,the
implementationoftheflightcontrollawsusingtheProportionalIntegralDerivative
(PID)controller,thetuningofthePIDgainsusingvariousmethodsandlastlyaflight
demonstrationtovalidatetheautonomouslandingsystem.
1.2.HistoricalbackgroundTheconceptofUAVbeganduringtheAmericanCivilWar,whentheNorthandthe
Southattemptedtobombeachothersammunitiondepotbylaunchingballoons
carryingexplosivedevicewhichwouldbereleasedatacontrolledtiming.However,
theactualbeginningstartedduringWorldWarII,whenacompanyChanceVought
Aircrafthadproposedbuildingmissileswithlandinggear,inordertosavecost.
8/12/2019 Autonomous Landing UAV
10/58
Introduction
Session 2008/2009
2 | P a g e
Recently,UAVsuchastheGlobalHawkandthePredator,haveachieved
considerablepopularity,whenitwasemployedtoprovideaerialsurveillanceaswell
asattack
missions
in
Afghanistan.
There
are
many
other
useful
applications
of
UAV
suchashomelandsecurity,cropdustingandtrafficmonitoring.
UAVcanbeclassifiedundertwodistinctcategories,FixedwingandRotary.Some
examplesofRotaryUAVincludehelicopter,MicroAirVehicleandOrganicAir
Vehicle,whereastheGlobalHawkandPredatorrepresentsFixedwingaircraft.
AccordingtoReinHardt[2],thenextgenerationofUAVswillbesmallerinsize,more
affordable,easiertotrainandmoreprecisethantheexistingUAVs.Also,UAVsare
expectedtobecapableofdetectingnuclear,biological&chemicalweapons,looking
intodoublecanopyjunglesandprovidelowcost,reliablecommunicationsanddata
relayacrossthebattlefield.Inurbanbuiltupareas,whereairspaceisoftenlimited,
VerticalTakeOffandLanding(VTOL)UAVisoftenemployed.
TheremotepilotingofaVTOLUAVisaverychallengingtaskwhichrequiresgreat
operatorskillandattention[4].Furthermore,mostmaneuverswouldrequirethe
pilottomaintainfullvisualcontactwiththeUAVatalltimes,especiallyduringthe
landingphase.Inaddition,someotherfactorsthatmightaffecttheRemotecontrol
(RC)performancearepoorpositionalaccuracy,pooraltitudeaccuracyandpilot
fatigue[4].
8/12/2019 Autonomous Landing UAV
11/58
Theory
Session 2008/2009
3 | P a g e
2. Theory2.1.HelicopterAerodynamics
ThefourworkingstatesofarotorinaxialflightaredescribedinAppendixII.In
particular,thevortexringstateshouldbeavoidedduringdescentasitmightresult
inhighlyunsteadyflowwithnonlinearityasaffirmedbyYaggy&Mort(1963).This
unsteadinesscancausesignificantbladeflapping,uncommandeddropindescent
rate,lossofcontroleffectiveness,andexcessivethrustfluctuations.
Figure1:(A)WakebehaviourOGE/IGE;(B)ThrustratioVsDistance
Groundeffectcanalsoaffecttheperformanceofahelicopter.Figure1Ashowsthe
wakebehaviorfromahoveringstateInandOutofgroundeffectandfigure1B
showstheincreaseinthrustratioatdifferenthoveringheightastestedby
Fradenburgh(1972)andHayden(1976).Theseresultssuggestsignificanteffectson
hoveringperformanceforheightsoflessthanonerotordiameter,wherethereisa
sharpincreaseinthrust.
8/12/2019 Autonomous Landing UAV
12/58
Theory
Session 2008/2009
4 | P a g e
2.2.PIDSystem
Figure2:BlockDiagramofPIDControlsystem
TheclassicalcontroltheorywithaclosedloopPIDcontrollerisusedtocontrolthe
altitudeoftheUAVasillustratedbytheblockdiagraminfigure2.Theultrasonic
sensorattached
to
the
UAV
provides
range
feedback
for
the
closed
loop
system
and
itsdataisalsocapturedbythecomputerfordataloggingpurposes.Severalmethods
oftuningthegainsofthecontrollerareproposed.
8/12/2019 Autonomous Landing UAV
13/58
Hardware and Setup
Session 2008/2009
5 | P a g e
3. HardwareandSetup3.1.UAVPlatform
Forthisproject,arotarytypeplatformwasselectedasitisabletomaintaina
hoveringpositionbeforethelandingcommandisinitiated.Duringtheinitialstage,a
hovercraftwhichusescoandereffecttoproduceliftwasexplored.However,dueto
thenatureofthisproject,aswellastheproblemsencountered,itwaseventually
replacedwithanotherofftheshelfplatform,thedraganflyerVTi.
3.1.1. CoanderEffectFlyingsaucerThephenomenonwhichcausesflownearlimitingsurfacetofollowthegeometrical
shapeofthesesurfacesisknownastheCoandereffect.Accordingtoresearcher
JeanLouisNaudin,theVTOLplatformwasabletoattaingoodcontrol,stabilityand
thrustwhichiscomparableorevenbetterthanaconventionalRChelicopter.In
accordancewith
his
built
plan,
asimilar
platform
was
modelled
using
CAD
software,
SolidworksinAppendixI,figure29,andbuiltcarefullyasshowninfigure3.
Figure3:ConstructionoftheCoanderEffectUAV
8/12/2019 Autonomous Landing UAV
14/58
Hardware and Setup
Session 2008/2009
6 | P a g e
However,subsequenttestsconductedontheplatformconcludedthatthecoander
effectwasunabletoproducesufficientliftaspromised.Detailedexperimentsthat
wereconducted
to
verify
the
lift,
as
well
as
some
minor
modifications
to
the
UAV
areattachedtoAppendixVforreference.
3.1.2. DraganflyerTiVTheflightcontrolsoftheDraganflyeroperatesolelyondifferentialthrustbetween
thefrontrearandleftrightmotor,wherebyanetresultantmomentcanbe
generatedalong
the
roll
axis
(x
axis)
or
the
pitch
axis
(y
axis)
to
produce
aroll
or
a
pitchmotionasshowninfigure4.
Figure4:FlightcontroloperationoftheDraganflyerVTi
Forinstance,topitchtheUAVup,thefrontmotorwillrotatefasterthantherear
motor.Anotheradvantageofthisplatformisthatnomechanicallinkageisrequired
asthereisnocontrolsurface.
8/12/2019 Autonomous Landing UAV
15/58
Hardware and Setup
Session 2008/2009
7 | P a g e
3.2.TestbedconstructionInordertoinvestigateandtunetheentireUAVsystem,differentjigswithdifferent
degreeof
freedom
(DOF)
are
required.
For
example,
in
order
to
tune
the
PID
controllerfortherollmotion,atestbedwhichrestrictstheUAVmotiontotheroll
axisonlyisrequired.Generally,thePIDcontrollermustbetunedseparatelyforthe
individualroll,pitchandyawaxis[11].
Forthisproject,thePIDcontrollerthatmustbetunedisinthetranslationalz
direction,withreferencetofigure4.Therefore,atestbedwith1DOFinthe
translationalzdirectionisrequired.Thetestbeddesignismodelledusing
SolidworksasshowninAppendixI,figure30.Thedimensionoftheceilingframeis
modelledaccordingtotheactualdimensioninthelaboratory.TheUAVismounted
onacarbonfibrecrossbar,andthecrossbarisjoinedtotheverticalpolystyrene
supportsby
four
prismatic
joints,
which
allows
translational
displacement
along
the
verticalsupportsonly.Therefore,thissetupcaneffectivelyconstraintheUAVtothe
translationalzdirectionasshowninfigure5.
8/12/2019 Autonomous Landing UAV
16/58
Hardware and Setup
Session 2008/2009
8 | P a g e
Figure5:ConstructedTestbed
3.3.SensorwithmountingThePING)))Ultrasonicrangesensorisattachedtoamountingmadeofbalsawood
andhighdensityfoamisusedtoprotectthesensorfromimpactwiththeground.
Figure6:UltrasonicdistancesensorattachedtoUAV
3.4.Microcontroller:BasicStamp
8/12/2019 Autonomous Landing UAV
17/58
Hardware and Setup
Session 2008/2009
9 | P a g e
ThemicrocontrollerBasicstampBS2pxandBS2pefromparallaxwasusedtoprocess
theinformationfromtheultrasonicsensorandtogeneratetherequiredsignal.
3.5.Communication
Figure7:Communicationofcontrolsystem
Figure7illustratestheoriginalcommunicationsofthelandingsystem.Tosimplify
theproblem,theconnectionbetweentheultrasonicsensorandthemicrocontroller
wasphysicallywired.Initially,asinglemicrocontrollerBasicstampBS2pxwasused
tocalculate
the
distance
from
the
range
sensor
as
well
as
processing
the
data
and
generatingthenecessarysignaltotheRadiofrequency(RF)transmitter.The
transmitterwillthenrelaythesignalstotheUAVviathetrainerport.
APinOutdiagramoftheFutabatransmitterisshowninAppendixI,figure31.In
ordertocontroltheUAVusingthemicrocontroller,thesixpinplugismodifiedand
only
three
of
the
pins
are
used:
Pin
2
(PPM
Out),
Pin
3
(PPM
In)
and
Pin
7
(Ground
shield).Pin2isusedtomonitorthesignalsgeneratedbythetransmitterandPin3is
usedtoreceivethesignalsfromthemicrocontrollerintothetransmitter.TheRadio
FrequencysignalisfinallytransmittedtothereceiveronboardtheUAV.
8/12/2019 Autonomous Landing UAV
18/58
Hardware and Setup
Session 2008/2009
10 | P a g e
3.6.Problemsencountered3.6.1. Pausewidth
Forbasic
stamp
microcontroller,
the
command
PAUSE
will
cause
adelay
where
no
signalwillbetransmittedtothepin.However,thesmallestunitis1millisecond
whereasthepauserequiredbetweenchannelsisonly0.4ms.Toovercomethis
problem,anotherpulsesignalwassenttoanotherdummypin,whichwillresultin
aninduceddelaytotheactualpinthatisconnectedtothetransmitter.
3.6.2. TrimmedsignalItwasobservedthatthetrimmingsonthetransmitteraffectthesignalsthatare
generatedquitesignificantly.AppendixI,figure33showstheFutabatransmitter
withthetrimcontrol.Thus,theUAVattachedtothetestbedshouldbeproperly
trimmedtomaintainhoverbeforethegeneratedsignalsaremeasured.
3.6.3. LagtimebetweenPulseTrain
8/12/2019 Autonomous Landing UAV
19/58
Hardware and Setup
Session 2008/2009
11 | P a g e
Figure8:Lagtimebetweenpulsetrain
Figure8ashowsthelagtimeof98msforthefulllandingprogramand8bshowsthe
reducedoroptimizedprogram,havingalagtimeof56ms.However,itisstillfar
fromthedelayrequiredof0.4ms.
Tosolvethisproblem,analternativecommunicationsystemisrequired.Figure9
showsthenewcommunicationsystemthatrequirestwomicrocontrollersto
operatesimultaneously.BS2pewasusedtocollectfeedbackdatafromthe
ultrasonic
sensor
and
acts
as
the
PID
controller
to
processes
the
retrieved
data.
It
is
alsoconnectedtothecomputerwhichwillsavetheinformationfordatalogging
purposes.AnothermicrocontrollerBS2pxwasconnectedtoBS2pethroughserial
communication.TheprimaryfunctionofBS2pxistogenerateregularpulsesof
signalstotheRFtransmitter.Thisisverycrucialaslonglagtimewillregisterasa
temporarylossoflinkwhichwillcausetheUAVtobecomeuncontrollableand
twitchesviolently.Therefore,thefasteststampBS2pxwithprocessingspeedofup
to19,000instructionspersecondwasemployedtoperformthisduty.
8/12/2019 Autonomous Landing UAV
20/58
Hardware and Setup
Session 2008/2009
12 | P a g e
Figure9:Newcommunicationsystem
Uponfurtherinvestigation,itwasdeducedthattheultrasonicsensor,runningat
about20Hz,iscausingthelonglagtime.Thus,theusageoftwobasicstampscan
effectivelyisolatetheinherentlagtimeproblemthatiscausedbythesensor.
AppendixI,figure34showstheconnectionsbetweenthetwostampswithflow
control.OneofthelimitationsofStampisthatwhenitissendingorreceivingdata,
itcannot
execute
other
instruction
and
vice
versa.
The
Stamp
does
not
have
aserial
bufferwhichispresentinothercomputers.Also,evenwhenrunningatthehighest
serialbaudrates,thereisinsufficienttimefortheStamptoreceivedata,processit
andexecuteanotherreceivingdatacommandintimetocatchthenextstreamof
data,unlesstherearesignificantpausesbetweendatatransmissions.Fortunately,
flow
control
can
be
used
to
overcome
this
problem
whereby
the
receiver
can
tell
the
senderwhenitisreadytoreceivethenextstreamofdata.Also,stampcanonly
transmitasinglebyteatatime.Therefore,thesignalthatwillbesentwasscaled
downby10inordertostaywithinthesinglebytelimitofvaluesbetween0255.
8/12/2019 Autonomous Landing UAV
21/58
Hardware and Setup
Session 2008/2009
13 | P a g e
3.7.Programmingalgorithm
Figure10:Flowchartofautonomouslandingsystem
Theflowchartabovesummarizestheprogrammingalgorithmfortheentire
autonomouslandingsystem.Atimeoutfunctionisprovidedtoaccountforcases
wherelag
time
exceeds
0.8ms.
In
such
cases,
this
function
will
generate
asimilar
pulsetrainastheonebefore.Thisistoensurethatthereisaregulargenerationof
pulsesignaltopreventlossoflink.
Anotherconditionthatisusedinthisalgorithmistocheckwhetherthecalculated
distanceislessthan20cm.Ifitistrue,thethrottlewhichcorrespondstolandingis
initiatedinstead
of
the
PID
controller
output.
8/12/2019 Autonomous Landing UAV
22/58
Experiment
Session 2008/2009
14 | P a g e
4. Experimentsconducted4.1. OperationoftheFutabaRFtransmitter
Figure11:ExperimentalsetuptomeasurePWMsignal
Experiment1:MeasurementofPWMsignalfromradiotransmitter
ThesignalsgeneratedbythetransmitterarePulseWidthModulation(PWM)signals.
ThisexperimentinvolvesthemeasurementofthePWMsignalgeneratedbythe
FutabaRFtransmitter,atdifferentsticksettings.Theequipmentthatwasusedin
thisexperimentisshowninfigure11.UsingaprobetotapthesignalfromPin2at
thetrainerport,therespectivepulsewidthatdifferentstickpositionscanbe
measuredusingadigitaloscilloscope(TectronixTDS3012).
8/12/2019 Autonomous Landing UAV
23/58
Experiment
Session 2008/2009
15 | P a g e
4.2. ExperimentsonDraganflyer
Figure12:
Experimental
setup
to
measure
generated
thrust
Experiment2:DeterminerelationshipbetweenThrottleandThrust
Asimpleexperimentwassetuptoestimatethegeneratedthrustatdifferent
throttlesettingasshowninfigure12.TheUAVwasattachedtoaweightandthe
platformwasplacedontoadigitalweighingscale.Theresultantthrustcanbe
measuredbytheweighingscaleatdifferentthrottlepositions.Twodifferentsetups
aredesignedtomeasurethethrustgeneratedattwodifferentaltitudes.Thisisdone
toestimatethethrustgeneratedIGEandOGE.Theassumptionisthattheattached
weightandweighingscaledonotinterferewiththethrustgeneratedbytherotors.
Experiment3:Testingandcalibrationofultrasonarsensor
TheParallaxPING)))ultrasonicsensorisusedtomeasurethealtitudeoftheUAV.It
ischosenprimarilybecauseofitsavailabilityinthelaboratoryaswellasthesuitable
rangeof2cmto3mwhichsatisfytherequirementofthisproject. Also,itisfully
8/12/2019 Autonomous Landing UAV
24/58
Experiment
Session 2008/2009
16 | P a g e
compatiblewiththemicrocontrollerBasicStamp.Inthisexperiment,theultrasonic
sensoristestedandcalibratedwiththeactualdistance.
Experiment4:Determinesystemplantmodel
Theaimofthisexperimentistodeterminetheplantmodelofthesystem.Froma
hoveringaltitudeof100cm,thethrottlewassteppeddownandtheheightvariation
datawasloggeddownusingthesoftwareStampPlotPro.Fromtheserawdata,the
rateofdescent(R.D)canbedetermined.Themagnitudeofthestepswasvariedand
thecorresponding
R.D
was
analysed
to
determine
the
systems
plant
model.
Experiment5:SimulationsusingMatlab,Simulink
Usingthederivedsystemplantmodel,thesystemwasmodelledusingMatlab,
Simulinkasshowninfigure13.
Figure13:SystemplantmodelledinSimulink
Simulationsarecarriedouttoexaminethetheoreticaloutputresponseofthe
systemgiven
astep
down
input.
The
gains
for
the
PID
controller
are
varied
to
determinethesystemresponse.ThetwomethodsoftuningthePIDcontroller,the
ZieglerNicholsmethodandtheTrialanderrormethod,wassimulated.
8/12/2019 Autonomous Landing UAV
25/58
Experiment
Session 2008/2009
17 | P a g e
Experiment6:Flighttest
Flight1:ScheduledProportionalcontrol
Twodifferent
values
of
proportional
gains
are
used
depending
on
the
height
of
the
UAV.Forheightofabove45cm,againof2.0isusedandforheightbelowthat,a
gainof1.0isused.Thisistoensurethattherateofdescentisreducedasit
approachestheground.
Flight2:Throttlereductionby20%
Thehovering
throttle
of
the
UAV
was
reduced
by
20%
and
the
rate
of
descent
of
the
UAVwasinvestigated.
Flight3:ProportionalDerivativecontrol
ItwasdeterminedthataPDcontrollerissufficientastheintegraltermwhichwill
compensateforsteadystateerrorisnotrequiredinthisautonomouslanding
system.The
appropriate
proportional
and
derivative
gains
that
are
obtained
from
thesimulationsusingSimulinkareusedinthisexperiment.Also,theactualsystem
responsecanbecomparedwiththesimulatedresponse.
Flight4:Hoveraboutsetpoint
UsingsimilarPDcontroller,UAVwascommandedtohoveratadesiredsetpoint.
8/12/2019 Autonomous Landing UAV
26/58
Results and Discussions
Session 2008/2009
18 | P a g e
5. ResultsandDiscussions5.1. Testingandcalibrationofultrasonicsensor
Figure14:
(A)
Ultrasonic
sensor
results;
(B)
Percentage
error
below
40cm
ItwasobservedthatnocalibrationoftheultrasonicsensorisrequirediftheStamp
usedtoreceivethesensordataisBS2pe.However,calibrationisrequiredifthe
StampusedisBS2px.Referringtofigure14A,themeasuredistance(Blue)isfound
tobedeviatedfromtheactualdistance(Green).Sincethedeviationislinear,a
correctionfactorof0.408wasdeterminedempirically.Thecorrecteddistanceis
depictedbytheredline.Itwasalsoobservedthatthepercentageerrorincreases
significantlywhenthesensorwasbelow40cm.Subsequently,anothercorrection
factorof0.440wasdeterminedthesamewayfordistancebelowtherangeof40cm.
Thedifferenceinpercentageerrorplotisshowninfigure14B.
8/12/2019 Autonomous Landing UAV
27/58
Results and Discussions
Session 2008/2009
19 | P a g e
5.2. Determinerelationshipbetweenthrottleandthrust
Figure15:PlotofThrustVsThrottle
Figure15showstherelationshipbetweenthethrottlestickpositionandthe
resultantthrustproducedbythefourrotors.Withthisestimation,theapproximate
throttlepositionthatisrequiredtodescendtheUAVofvaryingweightscanbe
calculatedaccordingly.
5.3. MeasurementofPWMsignalfromradiotransmitter
Figure16:PWMSignalsfromFutabatransmitter
8/12/2019 Autonomous Landing UAV
28/58
Results and Discussions
Session 2008/2009
20 | P a g e
Figure16showsthePWMpulsetrainthatwascapturedbytheoscilloscope.Itwas
observedthatthetimespanforasinglepulsetrainis20msregardlessofthestick
configurationsand
there
are
atotal
of
seven
channels.
Also,
the
pause
width
betweendifferentpulsesis0.4ms.However,thesynchronizationpulsevariesfrom
8.11msto8.83ms,dependingonthedifferentstickcombination.Thisisamore
accuraterepresentationofthesynchronizationpulseascomparedtotheconstant
valueof9msthatwasproposedbyKarWei[14].Theactualsynchronizationpulse
canbecalculatedasfollows:
Figure17showsthesevenpulsesthatarepresentinasinglepulsetrain.Eachof
thesepulsescorrespondstoachannelandtherefore,thereareatotalof7channels.
Channel1controlsaileron,channel2controlselevator,channel3controlsthrottle,
channel4controlsrudder,channel5controlsthermalintelligenceandlastly
channels6and7controlsthelandinggearswitchandflapknobwhicharenotused
inthisUAV.Also,therangeofpulsewidthforthethrottlecontrolismeasuredtobe
from0.74msto1.4ms.
8/12/2019 Autonomous Landing UAV
29/58
Results and Discussions
Session 2008/2009
21 | P a g e
Figure17:Sevenchannelsfromsinglepulsetrain
5.4. Relationshipbetweenhelicoptercontrolsandpulsewidth
Figure18:(a)PlotofThrottleVsPulsewidth;(b)PlotofThrustVsPulsewidth
Sincethisprojectinvolvesthemanipulationofthethrottlecontrol,thedifferent
throttlepositionswhichcorrespondtothepulsewidthofchannel3isexaminedin
detail.TheresultofPercentagethrottleagainstPulsewidthisshowninfigure18a.
Usinginformationfromsection5.2,theplotofThrustagainstPulsewidthis
obtainedandplottedinfigure18b.Fromthisresult,therequiredthrustcanbe
generatedwiththecorrectpulsewidth.
8/12/2019 Autonomous Landing UAV
30/58
Results and Discussions
Session 2008/2009
22 | P a g e
Therestofthepulsewidthsfromotherchannelsthatcorrespondstothe2extremes
ofthestickpositionareplottedinAppendixI,figure35.Forinstance,fullaileron
rightcorresponds
to
aminimum
pulse
width
of
0.78
ms
and
full
aileron
left
correspondstoamaximumpulsewidthof1.42ms.
5.5. Determinesystemplantmodel
Figure19:PlotsofRateofdescentVsPulsout
Thedescentratesatdifferentstepthrottledowninshowninfigure19ac.Atotalof
threetrialsareconductedandresultsareplottedinfigure19d.Thesystemsplant
modelcanbederivedfromthegradientofthelinewhichisabout1.7.
Therelevantequationstoderivetheplantmodelareshownbelow:
8/12/2019 Autonomous Landing UAV
31/58
Results and Discussions
Session 2008/2009
23 | P a g e
where canberepresentedby and represente ydb
Laplacetransform
SinceKis1.7, theplantmodelcanberepresentedbytheblockdiagrambelow.
Figure20:Systemsplantmodel
5.6. SimulationsusingMatlab,Simulink5.6.1. ZieglerNicholsmethod
Figure21:SimulationsusingZieglerNicholsmethod
ThesimulatedresultsusingtheZieglerNicholsmethodisshowninfigure21.Both
resultsshowshighovershootwithcomparativelylongsettlingtime.
5.6.2. ProportionalDerivativecontrol:TrialandErrormethod
8/12/2019 Autonomous Landing UAV
32/58
Results and Discussions
Session 2008/2009
24 | P a g e
ThesimulationresultsusingthePDcontrollerisshowninfigure22.Thesettlingtime
ismuchmoreacceptablecomparedtothepreviousmethod.Thus,thismethodwill
beused
in
the
actual
flight
test.
Figure22:SimulationsusingPDcontrol
5.7. Flighttest5.7.1. Flight1:Scheduledproportionalcontrol
Figure23:Resultsusingscheduledproportionalcontrol
Figure23showstheactualflightresultsusingscheduledproportionalcontrol
methodasdescribedearlier.Theresultisgoodwithfastsettlingtimeofabout1.7s
andcontrolledsmoothlanding.
8/12/2019 Autonomous Landing UAV
33/58
Results and Discussions
Session 2008/2009
25 | P a g e
5.7.2. Flight2:Throttlereductionof20%
Figure24:Resultsusingthrottlereductionmethod
Thelandingusingthrottlereductionof20%showssimilarlysmoothdescent.
However,theUAVhoverstoapointofabout20cmwhereitencountersground
effect.Asaresult,manualcontrolisrequiredtoforceittoland.
5.7.3. Flight3:ProportionalDerivativecontrol
Figure25:ResultsusingPDcontrol:(a)Kp:1.0/Kd:1.0;(b)Kp:3.0/Kd:1.0
ThesamegroundeffectisencounteredusingthePDcontrollerwithproportional
gainof1.0asshowninfigure25a.Forthiscase,theUAVhoveredtoaheightof
about40cmandrefusestodescendanyfurther.Thiscanbeovercomebyincreasing
8/12/2019 Autonomous Landing UAV
34/58
Results and Discussions
Session 2008/2009
26 | P a g e
theproportionalgainto3.0infigure25bwherethelandingissmoothwithquick
settlingtimeofabout1.3s.
5.7.4. Flight4:Hovertosetpoint
Figure26:HoveringtosetpointusingPDcontrol
UsingthesamePDcontrollerwithproportionalgainof3.0andderivativegainof1.0,
theUAViscommandedtoadesiredheightasshowninfigure26.Thecommandwas
initiatedataheightof35cmanditrisesquicklytothedesiredaltitudeafter1
oscillation.
Thetransientperformanceiscalculatedasfollows:
Risetime: (From0%to100%)
Peaktime:
8/12/2019 Autonomous Landing UAV
35/58
Results and Discussions
Session 2008/2009
27 | P a g e
Settlingtime: (Timetoreachandstaywithin5%limit)
Maximum%overshoot:
Thissystemcanbefurthertunedtoreduceovershootbyloweringtheproportional
gainandreducingthesteadystateerrorbyincludinganintegraltermintothe
controller.However,thesteadystateerrorisreasonableasitiswithinthe5%limit.
5.8. Analysiswithsimulatedplot5.8.1. Comparingsimulationandactualplot
Figure27:Comparisonbetweensimulatedandactualplot
Thesimulatedandactuallandingprofileisplottedforcomparisoninfigure27.The
redlineshowsthesimulatedplotusingMatlabandtherestoftheplotscorrespond
totheactualtestflightdata.Itcanbeconcludedthattheactualplotsfitthe
simulatedplot
reasonably
well.
5.8.2. RootlocusanalysisReferringtofigure13,thetransferfunctionofthesystemisderivedas:
8/12/2019 Autonomous Landing UAV
36/58
Results and Discussions
Session 2008/2009
28 | P a g e
Assumingunityfeedback:
ProportionalDerivativeControl:
OpenLooptransferfunction:
ClosedLooptransferfunction:
TakingKp=3,Kd=1,K=1.7,
ClosedLooptransferfunction:
Theopenlooptransferfunctioncanalsobewrittenintheform:
wherezandparethezeroandpoleoftheopenlooptransferfunction.Asthegain
changes,thevaluesofthecloselooppoleswillchangeandthusthetransient
responseand
stability.
The
root
locus
plot
is
aplot
of
the
loci
of
the
close
loop
poles
onthesplaneasthegainKvariesfrom0toinfinity.
Figure28:Rootlocusplot
8/12/2019 Autonomous Landing UAV
37/58
8/12/2019 Autonomous Landing UAV
38/58
Conclusion
Session 2008/2009
30 | P a g e
6. ConclusionsThisthesishaspresentedacompletesystemtocontroltheheightofaUAVusing
feedbackcontrol
from
an
ultrasonic
sensor.
The
method
of
communication
between
thedifferentmicrocontrollersandtransmitterwerediscussedaswellassomeofthe
problemsthatareassociatedwiththecommunications.Differentmethodsoftuning
thePIDcontrolsystemwereexploredwiththeaidofsimulationsusingMatlab,
Simulink.Finally,actualtestflightsarecarriedouttovalidatetheautonomous
landingsystem.
All
the
objectives
of
this
project
were
well
met.
8/12/2019 Autonomous Landing UAV
39/58
Recommendation
Session 2008/2009
31 | P a g e
7. RecommendationsforFurtherWork7.1. IntegratingcontrollerforRoll,PitchandYawInthisproject,aheightsensorisusedtoprovidefeedbackforthePIDcontrollerfor
altitudecontrol.However,thiscanbefurtherextendedtotheroll,pitchandyaw
motion.Inordertodoso,additionalsensorsarerequiredtoprovidefeedback
informationabouttheUAVsorientationorangularvelocity.Tiltsensorsorrategyro
canbeusedinsuchcasestoprovidecompensationfortheroll,pitchandyaw
motion.In
the
thesis
by
KarWei
[14],
he
had
successfully
used
atilt
sensor
to
compensatefortherollandpitchmoment.
Anotheralternativemethodistoextracttherawdatadirectlyfromthethreepiezo
electricgyrothatarealreadypresentonthecircuitboardDraganflyerVTi.However,
thiswouldrequireknowledgeaboutthecircuitboardtopreventdamageonanyof
thecomponentsonit.
7.2. CamerasystemtolocatelandingzoneAcamerasystemcanbeintegratedintotheUAVtolocatethelandingzonefrom
anotherposition.InthethesisbyZhikang[17],hehadusedcolorsegmentationto
segmentacoloredlandingzoneandapanandtiltcameratotrackontothetarget.
Finally,thepositionoftheUAVwascorrectedtothelandingzoneandsubsequently
landed.InordertocommunicatebetweenacomputerandaRFtransmitter,an
interfacePCTxbyEndurancewasused.
8/12/2019 Autonomous Landing UAV
40/58
References
32 | P a g e
References
[1]HaniphLatchman(2003,January17).BriefhistoryofUAVS.RetrievedMarch10,2009,fromhttp://aln.list.ufl.edu/uav/UAVHstry.htm
[2]ReinHardtJ.R.,JamesJ.E.&FlanaganE.M.(1999).FutureEmploymentofUAVs,JointForceQuarterly.RetrievedMarch10,2009,from
http://www.dtic.mil/doctrine/jel/jfq_pubs/0822b.pdf
[3] JoshuaHintze(2004,April).Autonomouslandingofarotaryunmannedaerialvehicleinanoncooperativeenvironmentusingmachinevision.BrighamYoung
University,DepartmentofElectricalandComputerEngineering
[4]TeinHau,Tan(2008,May).AutopilotUnmannedAerialVehicle.NationalUniversityofSingapore,DepartmentofMechanicalEngineering
[5] J.Gordon(2006).PrinciplesofHelicopterAerodynamics.CambridgeUniversityPress.
[6]A.R.S.Bramwell,G.Done&D.Balmford(2000).BramwellsHelicopterDynamics.ElsevierLtd.
[7]TomasB.Co(2004,February13).ZieglerNicholsMethod.MichiganTechnologicalUniversity.RetrievedMarch11,2009,from
http://www.chem.mtu.edu/~tbco/cm416/zn.html
[8] J.L.Naudin(2007,February25).TheGFSUAVproject,ACoandereffectflyingsaucer.RetrievedMarch11,2009,fromhttp://jlnlabs.online.fr/gfsuav/index.htm
[9]ChrisSmith(2009).TheAerodynamicsofaPingpongball.RetrievedMarch11,2009,from
http://www.thenakedscientists.com/HTML/content/kitchenscience/exp/the
aerodynamicsofapingpongball/
8/12/2019 Autonomous Landing UAV
41/58
References
33 | P a g e
[10] W.KlausandI.S.Martin(1999,May20).MisinterpretationsofBernoulli'sLaw.UniversityFrankfurt,DepartmentofPhysics.RetrievedMarch11,2009,
fromhttp://user.unifrankfurt.de/~weltner/
[11] WaiWeng,Kong&M.S.b.Zainal(2006).DesignandControlofaQuadRotorFlyingRobotforAerialSurveillance.UniversitiTeknologiMalaysia,Centerfor
ArtificialIntelligenceandRobotic.
[12] J.Martin,J.Williams,K.Gracey,A.Alvarez&S.Lindsay(2005,February).BASICStampSyntaxandReferenceManualVersion2.2.RetrievedMarch11,
2009,fromwww.parallax.com
[13] M.Azfar(2007).AerodynamicsandPropulsionofanIndoorUAV.NationalUniversityofSingapore,DepartmentofMechanicalEngineering
[14] KarWei,Chin(2007).FlightDynamicsandControlforanIndoorUAV.NationalUniversityofSingapore,DepartmentofMechanicalEngineering
[15] MartinHebel(2009).PrimertoUsingStampPlotPro,SelmaWareSolutions.RetrievedMarch11,2009,from
http://www.selmaware.com/stampplot/index.htm
[16] NickSacco(2002).HowtheDraganflyerFlies.RotoryMagazine.RetrievedMarch11,2009,from
http://www.rctoys.com/pdf/draganflyer3_rotorymagazine.pdf
[17] Zhikang,Lin(2008).Camerabasedvisionsystemforunmannedairvehicles(UAVs)operations.NationalUniversityofSingapore,DepartmentofMechanical
Engineering
8/12/2019 Autonomous Landing UAV
42/58
Appendix I
34 | P a g e
AppendixI. FiguresandTables
Figure29:ModelofCoandereffectUAVusingSolidworks
Figure30:TestbedmodelinSolidworks
8/12/2019 Autonomous Landing UAV
43/58
Appendix I
35 | P a g e
Figure31:PinOutdiagramofRFtransmitter,FutabaSkysport6T6YG
Figure32:Modifiedwiringintotrainerport
Figure33:Futabatransmittercontrolsdiagram
8/12/2019 Autonomous Landing UAV
44/58
Appendix I
36 | P a g e
Figure34:Serialcommunicationwithflowcontrol
Figure35:DescriptionofPulsewidthVsChannel
8/12/2019 Autonomous Landing UAV
45/58
Appendix II
37 | P a g e
AppendixII. Fourworkingstatesofarotorinaxialflight
Figure36:FlowvisualizationatvariousdescentvelocitiesusingShadowgraphy
Figure36showsthefourworkingstatesofrotorinaxialflightandthedescriptions
ofeachstatearesummarizedbelow:
a) NormalWorkingstate:Thetipvorticesfollowsmoothhelicoidaltrajectories.Theflowishighlyperiodicwith
asmoothslipstreamboundaryfreeofanysignificantdisturbances.Thisstate
encompassesclimb,withthelimitbeingthehoveringstate.
b) VortexRingstate:Forlowrateofdescent,thetipvortexfilamentsareconvectedclosertotheplaneof
therotorbutalsomoveradiallyoutwardawayfromit.Athigherdescentrates,the
tipvorticescomeveryclosetotherotorplaneandconsiderableunsteadiness
becomesapparent.Thiscanbeseenbythecontortionsinthetipvortextrajectories
8/12/2019 Autonomous Landing UAV
46/58
8/12/2019 Autonomous Landing UAV
47/58
Appendix III
39 | P a g e
AppendixIII.CoandereffectThephenomenonwhichcausesflownearlimitingsurfacetofollowthegeometrical
shapeofthesesurfacesisknownastheCoandereffect.Itonlyoccurswhentheflow
isnotforcedtochangeitsdirectiontooabruptlyinordertopreventtheformation
ofturbulenceandseparation.Theclassicexampleisaflowacrossaflatplanewith
anadjacenthalfcylinderasshowninfigure37below.
Figure37:Flowacrossalimitingsurface
In37a,theflowinitiallyfollowsthesurfaceofthecylinderwhicheventually
separatesatsomepointonthecurvedsurface.Anothersimpleexampleis
demonstratedin
5c,
when
water
is
dripped
down
the
back
of
aspoon,
it
will
tend
to
sticktothesurfaceandgetdeflected.Thisimportantbehaviourholdsforallflows
limitedbysmoothlycurvedsurfaceslikeaerofoils,streamlinedobstaclesandsails.
TheCoandereffectcanbeexplainedbyconsideringtheeffectsofviscosityofafluid.
In37b,duetoviscosity,somelayersoftheadjacentairattheendoftheflatsurface,
depictedby
dots,
are
carried
away
by
the
main
stream
flow.
As
aresult,
aregion
of
lowpressureisformedwhichgiverisetoanetforcewhichwillpulltheflowtowards
thecurvedsurface.
8/12/2019 Autonomous Landing UAV
48/58
Appendix IV
40 | P a g e
AppendixIV.ZieglerNicholstuningmethodTable1:ZieglerNicholstuningchart
where Kcistheproportionalgain
Iistheparameterthatscalestheintegralcontroller
Distheparameterthatscalesthederivativecontroller
KUistheultimategain
Kp,KiandKdaretheproportional,integralandderivativegains
ThetuningchartfollowsthePIDequation:
Inordertodeterminetheparameters,thefollowingstepsarecarriedout:
1. Setthecontrollertoproportionalcontrolonly.2. StepincrementthecontrollergainKcandwaitforasteadystateoutputbefore
increasingbyanothersubsequentstep.
3. ThecriticalorultimategainKu,isthevalueofKcthatwillresultsinasustainedperiodicoscillationintheoutput.
4. TheperiodofthisoscillationisknownastheultimateperiodPu.5. TherespectiveKc,IandDcanbedeterminedfromtheultimategainand
ultimateperiodaccordingtothechartabove.
8/12/2019 Autonomous Landing UAV
49/58
Appendix V
41 | P a g e
AppendixV. CoanderEffectflyingsaucerexperimentModificationstoUAV
Figure38:ModificationtoPlatform
SomemodificationswerecarriedouttoimprovetheUAVaftertheinitialmotortest.
1. Themotoraswellasthepropellerarerealignedtoensurethatitwasinthehorizontal
plane.
This
is
important
as
slight
misalignment
will
cause
the
propeller
tooscillateandvibrateexceedinglywhenthemotorrotates.Thiswasdoneusing
acircularairbubble.
2. Thespacingbetweenthepetalandtheductwasreducedtoincreaseairflow.3. Theairductwasdoublelayered.Thiswasdonetoimproveonitsrigidityto
maintain
its
cylindrical
structure
during
flight.
As
the
inner
diameter
of
the
duct
wasalsoreducedtoimproveontheairspeed,anyslightdeformationoftheduct
willcausethepropellertocollidewiththeduct.Lastly,theentranceandexitof
theductwaschamferedtoimproveairflow.
8/12/2019 Autonomous Landing UAV
50/58
Appendix V
42 | P a g e
J.L.NaudinExperiment
Experimentalsetup
AthrustexperimentdesignedbyJeanLouisNaudinwaspublishedonhiswebsite.
Figure39:J.Naudinsexperimentalsetup
Inhisexperiment,heusedablowertoblowacrossonepetaltosimulateairthat
movesthroughtheairductoverthesurfacesofthepetals.Aweightwasattachedto
theotheredgeofthepetalandwasplacedontoaweighingscale.Ananemometer
wasusedtomeasuretheairspeedatthedifferentlocationsofthepetal.
Results
Theresultthatwasobtainedfromhisexperimentisplottedinthegraphbelow:
Figure40:Naudinsresult
8/12/2019 Autonomous Landing UAV
51/58
Appendix V
43 | P a g e
Fromthisplot,itcanbededucedthataminimumairspeedof21m/sisrequiredat
theoutletoftheductedfaninordertogenerate533gofthrust,whichwasthe
overallweight
of
his
platform.
In
other
words,
the
take
off
thrust
required
is
533g.
Experimentconducted:Airspeedmeasurement
ExperimentalsetupandResults
Figure41:Experimentalsetupforairspeedmeasurement
Asimpleexperimentwasconductedtoverifytheairspeedatthedifferentpositions
ofthe
petal,
in
order
to
deduce
the
thrust
that
would
be
generated
according
to
Naudinsresult.
Figure42:Variablesofexperiment
8/12/2019 Autonomous Landing UAV
52/58
Appendix V
44 | P a g e
Theairspeedsatthethreelocations,using2differenttypesofpropeller,are
measuredandtheresultistabulatedbelow:
Table2:
Airspeed
test
results
Predictedthrustiscalculatedusingequationthatwasderivedinhisexperiment:
Conclusion
Itwasobservedthatthe2bladepropellerwasabletoproducemorethrustthanthe
3bladepropeller.Themaximumthrustthatcouldbeproducedbyalltheeight
petalswasevaluatedtobeonly143.8g.Thiswasbarelysufficienttoliftoffthe
platformwhichhasanoverallweightof570g,withoutincludingothercomponents
suchasservosandsensors.Thus,theusageofthisplatformforthisprojectwas
ruledout.
8/12/2019 Autonomous Landing UAV
53/58
Appendix VI
45 | P a g e
AppendixVI.Autonomouslandingprogram(Basic)Processor
Scheduledproportional
control
'~~~~~~~~SENDER/PROCESSOR~~~~~~~~~~~~~~~~
'{$STAMPBS2pe}
'{$PBASIC2.5}
'{$PORTCOM8}
'~~~~~~~~~~~~~~~~~~SetPin~~~~~~~~~~~~~~~~~~
SO PIN 1 'SerialOutPin
FC PIN 0 'FlowcontrolPin
'~~~~~~~~~~~BaudrateSelect~~~~~~~~~~~~~~~~
#SELECT$STAMP
#CASEBS2PET4800CON16572
T9600CON16468
#CASEBS2PX
T4800CON17197
T9600CON16780
#ENDSELECT
BaudCONT9600
'~~~~~~~~~~~~~ThrottleConfig~~~~~~~~~~~~~~~
'tMin CON 1600
'tMax
CON
1800
tLand CON 1400
tHover CON 1630
throttle VAR Word
throtsend VAR Byte
'~~~~~~~~~~~~~~PIDVariables~~~~~~~~~~~~~~~~
setpoint CON 5
error VAR Word
p VAR Word 'Proportionalterm
'~~~~~~~~~~~~~~~~~PING)))Variables~~~~~~~~~~~~~~
cmConstant
CON
2260
cmDistance VAR Word
time VAR Word
PAUSE500 'ForPlotting
DEBUG"!SPAN0,200",CR 'Altitudeaxis
DEBUG"!TMAX180",CR 'Timeaxis
8/12/2019 Autonomous Landing UAV
54/58
Appendix VI
46 | P a g e
DEBUG"!PNTS4000",CR 'Datapointsperplot
DEBUG"!TITLAltituteLog",CR 'Titletheform
DEBUG"!SHFTON",CR 'Plotshiftatmax
DEBUG"!TSMPOFF",CR
DEBUG"!SAVD
ON",CR
DEBUG"!SAVMON",CR
DEBUG"!NAMDPlotData.txt",CR
DEBUG"!NAMMPlotMsg.txt",CR
DEBUG"!PLOTON",CR 'Enableplotting
DEBUG"!RSET",CR 'ResetPlot
DO
PULSOUT15,5 'ToutfromPING)))
PULSIN15,1,time 'TintoPING)))>Timevariable
cmDistance=cmConstant**time 'DistancefromPING)))
DEBUGDECcmDistance,CR 'ForPlotting
error=setPoint cmDistance
IFcmDistance>45THEN 'AugmentProportionalGains
p=2*error
ELSEIFcmDistance
8/12/2019 Autonomous Landing UAV
55/58
8/12/2019 Autonomous Landing UAV
56/58
Appendix VI
48 | P a g e
DEBUG"!PNTS4000",CR '4000datapointsperplot
DEBUG"!TITLAltituteLog",CR 'Titletheform
DEBUG"!SHFTON",CR 'Allowplottoshiftatmax
DEBUG"!TSMPOFF",CR
DEBUG"!SAVD
ON",CR
DEBUG"!SAVMON",CR
DEBUG"!NAMDPlotData.txt",CR
DEBUG"!NAMMPlotMsg.txt",CR
DEBUG"!PLOTON",CR 'Enableplotting
DEBUG"!RSET",CR 'ResetPlot
DO
PULSOUT15,5 'ToutfromPING)))
PULSIN15,1,time 'TintoPING)))>Timevariable
cmDistance=cmConstant**time 'DistancefromPING)))
DEBUGDECcmDistance,CR
error(current)=setPoint cmDistance 'Calculateerror
p=3*error(current) 'ProportionalGain=3
error(delta)=error(current) error(previous)
d=error(delta) 'DerivativeGain=1
throttle=p+tHover+d MIN1500MAX 1800
IFcmDistance
8/12/2019 Autonomous Landing UAV
57/58
Appendix VI
49 | P a g e
Signalgenerator
'~~~~~~~~~RECEIVER/SIGNALGENERATION~~~~~~
'{$STAMPBS2px}
'
{$PBASIC
2.5}
'{$PORTCOM5}
'~~~~~~~~~~~~~~~~~~SetPin~~~~~~~~~~~~~~~~~~
SI PIN 0 'SerialInPin
FC PIN 1 'FlowcontrolPin
PP PIN 5 'PausePin
TP PIN 13 'TrainerPin
'~~~~~~~~~~StampBaudrateSelect~~~~~~~~~~~
#SELECT$STAMP
#CASEBS2PE
T4800CON16572
T9600CON
16468
#CASEBS2PX
T4800CON17197
T9600CON16780
#ENDSELECT
BaudCONT9600
'~~~~~~~~~~~~~~CALIBRATIONDATA~~~~~~~~~~~~~
ch1 CON 1115 'AileronStick:(1775)LeftMid(1375)Right(975)
ch2 CON 1380 'Elevator:(1725)UpMid(1400)Down(1025)
ch4 CON 1400 'Rudder
ch5
CON
2100
'Thermalch6 CON 1400
ch7 CON 1400
sync CON 10305 'Synchropulse
delay CON 375 'Pausepulse
lastdelay CON 260
'~~~~~~~~VariablesfromSerialINPUT~~~~~~~~~~~~~
throttle VARByte
prevthrottle VARWord
throtgen VARWord
DO
SERINSI\FC,Baud,2,timeout,[throttle] 'timeout:2units=0.8ms
throtgen=throttle*10
PULSOUTTP,ch1
PULSOUTPP,delay
PULSOUTTP,ch2
8/12/2019 Autonomous Landing UAV
58/58
Appendix VI
PULSOUTPP,delay
PULSOUTTP,throtgen
PULSOUTPP,delay
PULSOUTTP,ch4
PULSOUTPP,
delay
PULSOUTTP,ch5
PULSOUTPP,delay
PULSOUTTP,ch6
PULSOUTPP,delay
PULSOUTTP,ch7
PULSOUTPP,delay
PULSOUTTP,sync
prevthrottle=throtgen 'Storeslastsignal
LOOP
timeout: 'Generatelastsignal
throtgen=prevthrottle
PULSOUTTP,ch1
PULSOUTPP,delay
PULSOUTTP,ch2
PULSOUTPP,delay
PULSOUTTP,throtgen
PULSOUTPP,delay
PULSOUTTP,ch4
PULSOUTPP,
delay
PULSOUTTP,ch5
PULSOUTPP,delay
PULSOUTTP,ch6
PULSOUTPP,delay
PULSOUTTP,ch7
PULSOUTPP,delay
PULSOUTTP,sync
RETURN