QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Taylor, G. K. Articles by Thomas, A. L. R. Search for Related Content PubMed PubMed Citation Articles by Taylor, G. K. Articles by Thomas, A. L. R. Social Bookmarking                         What's this?

The Journal of Experimental Biology 206, 2803-2829 (2003)
doi: 10.1242/jeb.00501

Dynamic flight stability in the desert locust Schistocerca gregaria

Graham K. Taylor^* and Adrian L. R. Thomas

Department of Zoology, Oxford University, Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK

^* Author for correspondence (e-mail: graham.taylor{at}zoo.ox.ac.uk)

Accepted 16 May 2003

Here we provide the first formal quantitative analysis of dynamic stability in a flying animal. By measuring the longitudinal static stability derivatives and mass distribution of desert locusts Schistocerca gregaria, we find that their static stability and static control responses are insufficient to provide asymptotic longitudinal dynamic stability unless they are sensitive to pitch attitude (measured with respect to an inertial or earth-fixed frame) as well as aerodynamic incidence (measured relative to the direction of flight). We find no evidence for a `constant-lift reaction', previously supposed to keep lift production constant over a range of body angles, and show that such a reaction would be inconsequential because locusts can potentially correct for pitch disturbances within a single wingbeat. The static stability derivatives identify three natural longitudinal modes of motion: one stable subsidence mode, one unstable divergence mode, and one stable oscillatory mode (which is present with or without pitch attitude control). The latter is identified with the short period mode of aircraft, and shown to consist of rapid pitch oscillations with negligible changes in forward speed. The frequency of the short period mode (approx. 10 Hz) is only half the wingbeat frequency (approx. 22 Hz), so the mode would become coupled with the flapping cycle without adequate damping. Pitch rate damping is shown to be highly effective for this purpose — especially at the small scales associated with insect flight — and may be essential in stabilising locust flight. Although having a short period mode frequency close to the wingbeat frequency risks coupling, it is essential for control inputs made at the level of a single wingbeat to be effective. This is identified as a general constraint on flight control in flying animals.

Key words: stability, control, flapping flight, desert locust, Schistocerca gregaria, insect, flight dynamics, modes of motion, equations of motion, frequency response, stabilising pitch reaction, constant-lift reaction, flight speed, body angle

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				J. H. Wu, Y. L. Zhang, and M. Sun Hovering of model insects: simulation by coupling equations of motion with Navier-Stokes equations J. Exp. Biol., October 15, 2009; 212(20): 3313 - 3329. [Abstract] [Full Text] [PDF]

				T. L. Hedrick, B. Cheng, and X. Deng Wingbeat Time and the Scaling of Passive Rotational Damping in Flapping Flight Science, April 10, 2009; 324(5924): 252 - 255. [Abstract] [Full Text] [PDF]

				G. K. Taylor, M. Bacic, R. J. Bomphrey, A. C. Carruthers, J. Gillies, S. M. Walker, and A. L. R. Thomas New experimental approaches to the biology of flight control systems J. Exp. Biol., January 15, 2008; 211(2): 258 - 266. [Abstract] [Full Text] [PDF]

				B. W. Tobalske Biomechanics of bird flight J. Exp. Biol., September 15, 2007; 210(18): 3135 - 3146. [Abstract] [Full Text] [PDF]

				M. Sun and J. K. Wang Flight stabilization control of a hovering model insect J. Exp. Biol., August 1, 2007; 210(15): 2714 - 2722. [Abstract] [Full Text] [PDF]

				K. Tanaka and K. Kawachi Response characteristics of visual altitude control system in Bombus terrestris J. Exp. Biol., November 15, 2006; 209(22): 4533 - 4545. [Abstract] [Full Text] [PDF]

				R. J Bomphrey, G. K Taylor, N. J Lawson, and A. L.R Thomas Digital particle image velocimetry measurements of the downwash distribution of a desert locust Schistocerca gregaria J R Soc Interface, April 22, 2006; 3(7): 311 - 317. [Abstract] [Full Text] [PDF]

				G. K Taylor and R. Zbikowski Nonlinear time-periodic models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria J R Soc Interface, June 22, 2005; 2(3): 197 - 221. [Abstract] [Full Text] [PDF]

				M. Sun and Y. Xiong Dynamic flight stability of a hovering bumblebee J. Exp. Biol., February 1, 2005; 208(3): 447 - 459. [Abstract] [Full Text] [PDF]