Remote Terrain Navigation for Unmanned Air Vehicles

76 Pages·2016·1.37 MB·English

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Theses and Dissertations
2006-01-27
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Stephen R. Griffiths
Brigham Young University - Provo
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Griffiths, Stephen R., "Remote Terrain Navigation for Unmanned Air Vehicles" (2006). Theses and
Dissertations. 1059.
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REMOTETERRAIN NAVIGATIONFOR
UNMANNEDAIRVEHICLES
by
StephenRichard Griffiths
Athesissubmittedtothefacultyof
BrighamYoungUniversity
inpartialfulfillmentoftherequirementsforthedegreeof
MasterofScience
DepartmentofMechanicalEngineering
BrighamYoungUniversity
April2006
BRIGHAMYOUNGUNIVERSITY
GRADUATECOMMITTEEAPPROVAL
ofathesissubmittedby
StephenRichard Griffiths
This thesis has been read by each member of the following graduate committee and by
majorityvotehasbeenfoundtobesatisfactory.
Date TimothyW.McLain,Chair
Date RandalW.Beard
Date DerylO.Snyder
BRIGHAMYOUNGUNIVERSITY
As chair of the candidate’s graduate committee, I have read the thesis of Stephen Richard
Griffiths in its final form and have found that (1) its format, citations, and bibliographical
styleareconsistentandacceptableandfulfilluniversityanddepartmentstylerequirements;
(2) its illustrative materials including figures, tables, and charts are in place; and (3) the
final manuscript is satisfactory to the graduate committee and is ready for submission to
theuniversitylibrary.
Date TimothyW.McLain
Chair,GraduateCommittee
AcceptedfortheDepartment
MatthewR.Jones
GraduateCoordinator
AcceptedfortheCollege
AlanR.Parkinson
Dean,Ira A.FultonCollegeof
EngineeringandTechnology
ABSTRACT
REMOTETERRAIN NAVIGATIONFOR
UNMANNEDAIRVEHICLES
StephenRichard Griffiths
DepartmentofMechanicalEngineering
MasterofScience
Therearemanyapplicationsforwhichsmallunmannedaerialvehicles(SUAVs)are
wellsuited,includingsurveillance,reconnaissance,searchandrescue,convoysupport,and
short-range low-altitude perimeter patrol missions. As technologies for microcontrollers
andsmallsensorshaveimproved,sohavethecapabilitiesofSUAVs. Theseimprovements
inSUAVperformanceincreasethepossibilityforhazardousmissionsthroughmountainous
andurbanterraininthesuccessfulcompletionofmanyofthesemissions.
The focus of this research was on remote terrain navigation and the issues faced
whendealingwithlimitedonboardprocessingandlimitedpayloadandpowercapabilities.
Additionalchallengesassociatedwithcanyonandurbannavigationmissionsincludedreac-
tivepathfollowing,sensornoise,and flighttestdesignandexecution. Themainchallenge
was for an SUAV to successfully navigate through a mountainous canyon by reactively
alteringitsownpreplannedpathtoavoidcanyonwallsandotherstationaryobstacles.
A robust path following method for SUAVs that uses a vector field approach to
track functionally curved paths is presented along with flight test results. In these results,
the average tracking error for an SUAV following a variety of curved paths is 3.4 m for
amplitudes ranging between 10 and 100 m and spatial periods between 125 and 500 m.
Additionally,a reactive path following method is presented that allows a UAV to continu-
ally offset or bias its planned path as distance information from the left and right ranging
sensors is computed. This allows the UAV to to center itself between potential hazards
evenwithimperfectwaypointpathplanning. FlightresultsofanSUAVreactivelynavigat-
ingthroughmountainouscanyonsexperimentallyverifythefeasibilityofthisapproach. In
aflighttestthroughGoshenCanyonincentralUtah,anSUAVbiaseditsplannedpathby3
to 10 m to the right as it flew to center itself through the canyon and avoid the possibility
ofcrashingintoacanyonwall.
v
ACKNOWLEDGMENTS
I would like to thank Professors Tim McLain, Randy Beard, and Deryl Snyder
for all their help in conducting this research. I also need to thank all members of the
MAGICCLab,especiallythosethathelpedinthecollectionofflightdata,thedevelopment
ofthenavigationalmethods,thedesignandconstructionofopticflowsensors,andwiththe
construction of the UAV sensor platform including Blake Barber, Dave Johansen, Derek
Nelson, Derek Kingston, Andrew Eldredge, Jon Ostler, Joseph Jackson, Nathan Knoebel,
AndrewCurtis,SteveOsborne,andNeilJohnson. Iamalsoextremelygratefultomyloving
wife,Anna,for heretirelesssupport.
Contents
Acknowledgments vi
ListofTables ix
ListofFigures xii
1 Introduction 1
1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 LiteratureReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 DocumentOrganization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Experimental Apparatus 7
2.1 UAVSimulationEnvironment . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 FlightTestHardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 OpticFlowBasedRanging . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4 PreliminaryOpticFlowSensor . . . . . . . . . . . . . . . . . . . . . . . . 12
2.5 LensSelection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.6 FocusingProcedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.7 SampleRate Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.8 OpticFlowRangingResults . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.9 SensorOrientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.10 NewPrototypeOpticFlowRangingSensor . . . . . . . . . . . . . . . . . 20
2.11 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
vii
3 ReactiveTerrain Navigation 23
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2 ReactiveTerrainNavigationUsingPathBiasing . . . . . . . . . . . . . . . 25
3.3 PathBiasingImplementation . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.4 SimulationResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.5 FlightTestResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.5.1 TreeAvoidance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.5.2 CanyonNavigation . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4 Curved Path Following 35
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.1.2 LiteratureReview . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.2 ProblemDescription . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.3 TechnicalApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.3.1 ControlApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.3.2 ImplementationIssues . . . . . . . . . . . . . . . . . . . . . . . . 44
4.3.3 EffectsofModelError . . . . . . . . . . . . . . . . . . . . . . . . 47
4.3.4 BoundingFollowingError . . . . . . . . . . . . . . . . . . . . . . 49
4.4 FlightTestResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5 Conclusionsand Future Work 57
5.1 OpticFlowRanging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.2 ReactiveTerrainNavigation . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.3 CurvedPathFollowing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Bibliography 60
viii
List of Tables
3.1 StepsofPathOffsettingMethod. . . . . . . . . . . . . . . . . . . . . . . . 27
ix