Leif Ristroph a,1, Attila J. Bergou a, Gunnar Ristroph b, Katherine Coumes c, Gordon J. Berman a, John Guckenheimer d, Z. Jane Wang e, and Itai Cohen a
-Author Affiliations
aDepartment of Physics, Cornell University, Ithaca, NY 14853;
bIJK Controls, Dallas, TX 75231;
cSchool of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853;
dDepartment of Mathematics, Cornell University, Ithaca, NY 14853; and
eDepartment of Theoretical and Applied Mechanics, Cornell University, Ithaca, NY 14853
Communicated by Jacob N. Israelachvili, University of California, Santa Barbara, CA, January 22, 2010 (received for review September 11, 2009)
Abstract
Just as the Wright brothers [SIC: Alberto Santos-Dumont] implemented controls to achieve stable airplane flight, flying insects have evolved behavioral strategies that ensure recovery from flight disturbances. Pioneering studies performed on tethered and dissected insects demonstrate that the sensory, neurological, and musculoskeletal systems play important roles in flight control. Such studies, however, cannot produce an integrative model of insect flight stability because they do not incorporate the interaction of these systems with free-flight aerodynamics. We directly investigate control and stability through the application of torque impulses to freely flying fruit flies (Drosophila melanogaster) and measurement of their behavioral response. High-speed video and a new motion tracking method capture the aerial “stumble,” and we discover that flies respond to gentle disturbances by accurately returning to their original orientation. These insects take advantage of a stabilizing aerodynamic influence and active torque generation to recover their heading to within 2° in < 60 ms. To explain this recovery behavior, we form a feedback control model that includes the fly’s ability to sense body rotations, process this information, and actuate the wing motions that generate corrective aerodynamic torque. Thus, like early man-made aircraft and modern fighter jets, the fruit fly employs an automatic stabilization scheme that reacts to short time-scale disturbances.
flight control insect flight stability perturbation fruit fly
Footnotes
1To whom correspondence should be addressed. E-mail: lgr24@cornell.edu.
Author contributions: L.R., J.G., Z.J.W., and I.C. designed research; L.R. and K.C. performed research; L.R., A.J.B., G.R., K.C., G.J.B., J.G., Z.J.W., and I.C. analyzed data; and L.R. and I.C. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/1000615107/DCSupplemental.
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