The DelFly: Design, Aerodynamics, and Artificial Intelligence of a Flapping Wing Robot

221 Pages·2016·9.33 MB·English

by  G.C.H.E. de Croon

G.C.H.E. de Croon
M. Perçin
B.D.W. Remes
R. Ruijsink
C. De Wagter
The DelFly
Design, Aerodynamics,
and Artificial Intelligence
of a Flapping Wing Robot
The DelFly
G.C.H.E. de Croon M. Perçin
(cid:129)
B.D.W. Remes R. Ruijsink
(cid:129)
C. De Wagter
The DelFly
Design, Aerodynamics, and Artificial
Intelligence of a Flapping Wing Robot
123
G.C.H.E.deCroon R. Ruijsink
Delft University of Technology Delft University of Technology
Delft Delft
TheNetherlands TheNetherlands
M.Perçin C. DeWagter
Delft University of Technology Delft University of Technology
Delft Delft
TheNetherlands TheNetherlands
B.D.W. Remes
Delft University of Technology
Delft
TheNetherlands
ISBN978-94-017-9207-3 ISBN978-94-017-9208-0 (eBook)
DOI 10.1007/978-94-017-9208-0
LibraryofCongressControlNumber:2015952042
SpringerDordrechtHeidelbergNewYorkLondon
©SpringerScience+BussinessMediaDordrecht2016
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Foreword
WhenIwasyoung,Iwasfascinatedbyallflyingthings—rangingfromsmallmodel
helicopters to flying birds. At the time, the only model ornithopters were rubber
band powered. After twisting the rubber band multiple times, such a lightweight
balsawood ornithopter would fly for several metres, giving a brief impression of
what an artificial flying insect would look like.
The extreme weight restrictions of such ornithopter models have considerably
delayed the development of flapping wing vehicles with respect to rotorcraft or
fixed wing vehicles. Only when the computer and mobile phone industry went
sufficientlyfarintheminiaturisationofelectronicsandbatteries,itbecamepossible
to create electrically driven flapping wing vehicles. The first flapping wings still
quite resembled their rubber band ancestors, but along the line many new designs
have sprung up. On the one hand, the on-board electronics allowed new actuator
designs. For instance, the Vamp flapping wing toy I developed for a toy company
was able to turn by changing the incidence of the wings. On the other hand,
electronics allowed the further downscaling of the design. In 2007, I presented the
‘Hummer’flappingwingattheIMAVinToulouse,France.Itweighedamere1g.
Despite the technical advances and increasing scientific insights, flapping wing
vehicles are still a rather uncharted domain. This book is the first of its kind to try
and shed light on the ensemble of disciplines relevant to performing full missions
withflappingwingvehicles.TheDelFlyflappingwingprojectisuniqueduetothe
many aspects that are studied, ranging from propulsion to aerodynamics and even
artificial intelligence.
The reader will not only be impressed by the latest feats in autonomous flight
and the latest insights into flapping wing aerodynamics, but will definitely profit
from the experience and expertise conveyed by the DelFly team members. The
book provides (sometimes surprising) insights in flapping wing design principles,
butalsogivesveryconcretepointerstotheconstructionofaflappingwingvehicle
with relatively cheap, commercially available components. Although the book is
structured around the DelFly project, I would therefore recommend it to anyone
v
vi Foreword
who is interested in building or performing research on flapping wing vehicles on
his or her own. In this way, it will definitely spur the further progress on flapping
wing vehicles.
Petter Muren
CEO Proxdynamics
Preface
TheDelFlyprojectthatisattheheartofthisbookhasitsoriginsin2005asadesign
synthesisprojectforstudents.Thegoaloftheprojectwasto‘designaflappingwing
UAV of <50 g with on-board camera that will impress the jury of the European
MicroAirVehicleconferenceandcompetitions2005’.Afterflyingthe35cmwing
span and 21 g DelFly I at the EMAV 2005, winning the prize for ‘most exotic
MAV’, the DelFly project was continued by the faculty of Aerospace Engineering
of Delft University of Technology. It resulted in the creation of the Micro Air
Vehicle Laboratory, which focuses on the design and study of all types of auton-
omous MAVs.
In 2006, with financial support of TNO (Netherlands Organisation for Applied
Scientific Research), the DelFly II project was defined: this time the goal was to
makeaflappingwingMAVwhichwouldfitinaspherewithadiameterof30cm.
TheDelFlyIIwaspresentedoneyearlaterin2007.Itsurpassedtheproject’sgoals:
besides reducing the wing span to 28 cm, the flight envelope was considerably
increased. The DelFly II is able to fly forward at 7 m/s, hover, and even fly
backward at −1 m/s.
DelFly II’sbroad flight envelopeandon-board camera havemade it adesirable
study object both for investigating the airflow around the flexible wings and for
achieving autonomous flight capabilities. The insight into the structural and aero-
dynamic properties of the DelFly II first led to the successful design of the DelFly
Micro, presented in June 2008. The DelFly Micro is currently still the smallest
(10 cm wing span) and lightest (3.07 g) flapping wing MAV in the world that
carries both a camera and a video transmitter—a fact mentioned in the Guinness
Book of Records 2010. Concerning autonomous flight, we have developed algo-
rithmstocontinuallyincreasethecapabilitiesoftheDelFly.Wedidnotonlyapply
these techniques to a laboratory setting, but have been demonstrating these tech-
niquesalsointheIMAVcompetitions.TheDelFlyIIwasthefirstIMAVentryever
to perform autonomous flight indoors, successfully flying an 8-shape figure in the
indoordynamicsmissionattheEMAV2008.AttheIMAV2010inBraunschweig,
Germany, the DelFly II was the only MAV that flew autonomously during the
dynamics competition and it won the general first prize (beating all other types of
MAVs) in the exploration competition. At the end of 2013 improvements to the
motor and wings have allowed the design of the DelFly Explorer, the world’s first
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viii Preface
fully autonomous flapping wing MAV. The DelFly Explorer carries a 4 g stereo
visionsystem.Itcantake-off,keepitsheight,andavoidobstaclesforaslongasits
battery lasts—with all sensing and processing performed on-board.
The design of an autonomously flying flapping wing MAV requires knowledge
and expertise in various areas, including materials, aerodynamics, electronics,
propulsion, flight control, and artificial intelligence. This book intends to convey
theknowledgewegainedintheseareastoresearchers,students,orenthusiaststhat
areinterestedinflying robotsingeneral orflappingwingMAVsinparticular.The
main body of the book explains the scientific and engineering work performed to
arrive at the current design and capabilities of the DelFly, always putting it in the
perspectiveofotherworkon(flappingwing)MAVs.Thein-depthchaptersinclude
a general introduction so that readers familiar with one of the mentioned domains
will be able to follow the research in the other domains as well.
We hope that the ensemble of scientific, engineering, and practical insights
contained in this book will further stimulate the research on flapping wing Micro
Air Vehicles.
Delft Guido de Croon
June 2015 Mustafa Perçin
Bart Remes
Rick Ruijsink
Christophe De Wagter
Acknowledgments
Asmentionedinthepreface,theDelFlyProjectstartedoutasastudentassignment,
and over the years many people have made significant contributions. We are
thankfulforalloftheirworkandconstructiveideas.Inparticular,wewouldliketo
thank D. Lentink—one of the initiators of the project and a contributor to the
DelFly I andII. Moreover, we are verygrateful to B. van Oudheusden and H. Bijl
fromtheaerodynamicsdepartmentofTUDelft,withwhomwehavecollaboratedon
allaerodynamicsstudies.Furthermore,wearegratefultothefollowingpersonsfrom
theaerodynamicsdepartment(B.Bruggeman,K.M.E.deClercq,M.H.Groen),from
the MAV-lab (N. Bradshaw, A. Koopmans, K. Lamers, T. Reichert, K. Scheper,
S.Tijmons,J.Verboom),fromthecontrolgroup(S.Armanini,J.Caetano,C.C.de
Visser,E.deWeerdt),andfromtheinitialDelFlyIstudentgroup(A.Ashok,K.M.E.
de Clercq, D.A.J. van Ginneken, C.J.G. Heynze, S.R. Jongerius, A.N.A. Kacgor,
R.C.A. Lagarde, P. Moelans, W.V.J. Roos, M.H. Straathof, G.J. van der Veen).
In addition, we are grateful for the interesting discussions with P. Muren, CEO of
Proxdynamics, and the feedback from V. Trianni, S. Tijmons and M. Karasek in
reviewing chapters for this book. We would also like to thank M. van Tooren,
B. Droste, H. Bijl, J.A. Mulder, M. Mulder and M.P. Oosten, who have been of a
great support toour efforts.
ix
Contents
1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Flying like Animals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Flight Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Intelligence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Flapping Wing Micro Air Vehicles. . . . . . . . . . . . . . . . . . . . 5
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Part I Design and Materials
2 Introduction to Flapping Wing Design. . . . . . . . . . . . . . . . . . . . . 9
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 General Design Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Tail Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4 Wing Configuration and Design . . . . . . . . . . . . . . . . . . . . . . 12
2.5 Control and Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.5.1 Actuation Strategies. . . . . . . . . . . . . . . . . . . . . . . . . 15
2.5.2 Actuators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.6 Energy and Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.6.1 Flight Efficiency. . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.6.2 Energy Storage Materials. . . . . . . . . . . . . . . . . . . . . 19
2.6.3 Trading Off Battery Mass and Payload Mass . . . . . . . 22
2.7 Drive and Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3 Mechanical Design and Materials . . . . . . . . . . . . . . . . . . . . . . . . 31
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.2 General Concept. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.3 Crank Mechanism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.4 Wings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.5 Tail. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.6 Fuselage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
xi