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after Nachtigall, 1978
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‘Quasi-steady’ analysis (blade element theory)
total force liftn dragn liftn = ½ CL (an) Un2 r S dragn = ½ CD (an) Un2 r S Un ‘Quasi-steady’ analysis (blade element theory) an wind tunnel CL CD 0.5 1.0 U an drag = S dragn N lift = S liftn
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range needed to support flight
1 2 3 4 - drag coefficient lift coefficient locust f c fruit fly crane fly range needed to support flight 1.3 0.8
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2D wing model at 45o angle of attack
leading edge vortex leading edge direction of motion trailing edge
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early late early late 2p increase from leading edge vortex
value required For QSBE
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Start of motion at low angle of attack
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Start of motion at high angle of attack
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leading edge vortex
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RoboFly
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DPIV and force measurement
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DPIV and force measurement
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2D translating flat plate 3D revolving flat plate at low Re
Karman street leading edge vortex 3D revolving flat plate at low Re prolonged attachment
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Ftrans CD CL lift total a U drag force coefficients
- 9 1 8 2 7 3 6 4 5 . angle of attack (degs) force coefficients CL CD 1 2 3 3.0 time (secs) CD CL 1.5 -1.5 45o -9o
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1.8 1.3 0.8 lift coefficient drag coefficient 1 2 3 4 - locust f c
1 2 3 4 - drag coefficient lift coefficient locust f c fruit fly crane fly flapping model fruit fly 1.8 1.3 0.8
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vs. u CL CD 3 constant angular velocity (72 deg/sec) 2 1
constant forward velocity (0.157 m/s) -1 1 2 3 4 CD
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3D wing at 45o angle of attack, Re 110
Translating model 3D wing at 45o angle of attack, Re 110 David Lentink
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3D model at 45o angle of attack, Re 110
Revolving motion 3D model at 45o angle of attack, Re 110 David Lentink
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3 2 1 4 3. stroke reversal 2. rotational lift 1. delayed stall
downstroke upstroke 3. stroke reversal 3 2. rotational lift 2 1. delayed stall 1 4. wake capture &added mass 4
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down up stroke cycle up down 1.5 1.0 0.5 net force (10-5 N) measured
net force (10-5 N) measured force translational quasi-steady
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Altschuler, et al., 2005 PNAS
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Dear Prof. Dickinson, July 28, 2006
I report on aviation for The Wall Street Journal and wonder if I could trouble you for a professional judgment. Some entrepreneurs attempting to build a large commercial aircraft with small flapping wings have approached me to write a story about their project, and I'm trying to get a sense of whether their idea is at all realistic. They say their design is based, in part, on your research and development work. But obviously there is a huge difference between simulating a tiny insect and building a 100-passenger aircraft. The company is called JCR Technology, in case you have come across them. Their website, which so far seems only to be in French, has information about their design and some computer-graphic simulations. Would you or someone in your lab have a few minutes to look at this and assess whether it is realistic to develop or simply to far-fetched? I would be happy to call to discuss your work more, and how it has prompted this idea. Best regards, Dan Michaels
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JCR3D1c JCR_demo_c
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Integrative Approach Behavior sensory systems central nervous system
feedback olfaction mechano- vision Behavior dynamics& environment kinematics & forces central nervous system musculoskeletal system motor commands
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sensory system of flies Each wing stroke, the fly’s brain
Ocelli (300 cells) light-based orientation Wing Sensors (1000 cells) wing loading and contact Halteres (900 cells) angular rate gyroscope Eyes (8800 cells) image & optic flow sensor Antennae (2000 cells) olfaction, hearing, airspeed Each wing stroke, the fly’s brain integrates input from 15,000 cells. 0.5 mm
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Tammero&Dickinson, JEB 2002, Mark Fry, Ros Sayamen
infrared light infrared sensitive cameras fabric enclosure 10 sec -1200 1200 velocity (o s-1) angular Flyorama2 Slowed new saccade side view side view top view 5000 frames/sec, 150 msec duration Tammero&Dickinson, JEB 2002, Mark Fry, Ros Sayamen
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visual feedback
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Saccades are triggered by visual input.
number 50 25 +90 -90 saccade angle ~90o 50% ~90o Tammero&Dickinson, JEB 2002a
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Flies turn away from expansion.
“fly’s eye view” flight arena Emd movie Flies turn away from expansion. Tammero&Dickinson, JEB 2002a
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‘closed-loop’ flight simulators
angular velocity of stripe gain left- right stroke amplitude fly IR diode LED display wingbeat analyzer
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Stripe Fixation Michael Reiser Flight_start.wmv Reiser_stripe_fixation
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fixation/expansion Collision avoidance
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summary of expansion reflexes
left center right
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musculoskeletal mechanics
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power muscles upstroke muscles downstroke muscles
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steering muscles b1 (first basalar)
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b1 50 ms wing motion
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steering muscle control
phase advance phase delay
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aerodynamics
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high speed camera IR LED panel visual target flight path
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Saccade with forces v3
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kinematics changes during saccades
2) tilt of stroke plane 30 degs 1) increase in stroke amplitude 0.25 1.0 yaw torque (10-8 Nm)
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What triggers counter-turn?
torque to turn counter-torque to stop turning left right What triggers counter-turn?
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mechanosensory feedback
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magnetic tether IR camera LED arena CPU mirror magnet N S
Loose tether saccade
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‘loose’ saccades vs. ‘rigid’ saccades
torque with rigid tether angular velocity with loose tether 400 os -1 100 ms 5x10-9 nNm eyes halteres
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halteres pitch Coriolis force sensor arrays Flapping_nat
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time (ms) 100 200 300 400 500 orientation (deg) 50 150 stimulus fly
100 200 300 400 500 orientation (deg) 50 150 stimulus fly saccade002p7
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rotation against rotation with weighted haltere ablated haltere
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haltere feedback shortens saccades
*** normal , rotation with fly rotation against fly mass on haltere no haltere 60 50 40 |amplitude| (deg) 30 20 10
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summary of haltere reflex
Amir Fayyazuddin summary of haltere reflex wing sensors phase advance phase delay steering motor neuron haltere sensors steering motor neuron wing input delay haltere input advance
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working hypothesis small change in wing stroke accelerates animal
halteres detects rotation and trigger counter-turn visual expansion triggers saccade fly continues on new heading.
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