Meeting Abstract

101.5  Sunday, Jan. 6  Agile airframes I: maneuverability from abdominal actuation DYHR, JP*; COWAN, NJ; MORGANSEN, KA; DANIEL, TL; Univ. of Washington; Johns Hopkins Univ.; Univ. of Washington; Univ. of Washington jdyhr@uw.edu

Flying animals face trade-offs between maintaining stability versus the ability to accomplish quick maneuvers. Unlike terrestrial or aquatic locomotion, flight requires the active and continuous generation of lift forces and control along multiple degrees of freedom. For insects, maintenance of flight stability is particularly difficult about the pitch axis, which is further destabilized by oscillations generated by the periodic forcing of the wing beats. This instability requires sensory feedback to actively coordinate motor responses to pitch stimuli in order to stabilize flight. Here we investigate the extent to which pitch instability can be controlled, not by the wings, but through the deformation of the animals’ “airframe” via abdominal flexion. To accomplish this, we developed analytic methods for determining how control of abdominal angle in the hawkmoth Manduca sexta contributes to stability. By combining measured sensory gains and delays with a model of a pitching flexing animal we found that moths operate on the very edge of stability, within 1% of the dynamic range. Thus, small changes in control surfaces can move the animal to unstable (and maneuverable) dynamics. In this way, the animal may take advantage of multiple motor outputs, such that small changes in single outputs can quickly shift the animal to an agile regime, while the other outputs are available to quickly stabilize the animal.