title: Fruit flies modulate passive wing pitching to generate in-flight turns.
abstract: Flying insects execute aerial maneuvers through subtle manipulations of their wing motions. Here, we measure the free-flight kinematics of fruit flies and determine how they modulate their wing pitching to induce sharp turns. By analyzing the torques these insects exert to pitch their wings, we infer that the wing hinge acts as a torsional spring that passively resists the wing's tendency to flip in response to aerodynamic and inertial forces. To turn, the insects asymmetrically change the spring rest angles to generate asymmetric rowing motions of their wings. Thus, insects can generate these maneuvers using only a slight active actuation that biases their wing motion.
authors.affiliation: Department of Physics, Cornell University, Ithaca, New York 14853, USA. ajb78@cornell.edu
authors.forename: Attila J
authors.initials: AJ
authors.lastname: Bergou
authors.forename: Leif
authors.initials: L
authors.lastname: Ristroph
authors.forename: John
authors.initials: J
authors.lastname: Guckenheimer
authors.forename: Itai
authors.initials: I
authors.lastname: Cohen
authors.forename: Z Jane
authors.initials: ZJ
authors.lastname: Wang
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004331:Drosophila melanogaster / Q000502:physiology*; D005426:Flight, Animal / Q000502:physiology*; D008027:Light; D008954:Models, Biological; D013997:Time Factors; D014921:Wings, Animal / Q000502:physiology*