Meeting Abstract
10.4 Tuesday, Jan. 4 Translational and Rotational Components of Low Speed Turning in the Pigeon Columba livia ROS, IG*; BADGER, MA; PIERSON, AN; BASSMAN, LC; BIEWENER, AA; Harvard U.; U.of Cal., Berkeley; Harvey Mudd College; Harvey Mudd College; Harvard U. ivo.ros@gmail.com
The ability to maneuver is likely of fundamental importance to animals in natural conditions; however, adaptations for the maneuvering ability are likely less obvious than adaptations for flight itself. Insight into the control of flight maneuvers requires understanding the mechanics and aerodynamics, but to date, has remained elusive. Four rock pigeons were trained to negotiate a level 90-degree turn with detailed wing and body dynamics analyzed, based on body segment inertial data and 11 high speed camera views (250 Hz). Linear whole body accelerations were determined using center of mass (CoM) calculations. Aerodynamic torques were estimated as the rate changes of 3D angular momentum. Linear CoM-accelerations always maintained a relatively uniform direction in the body frame. In the inertial frame, by contrast, linear CoM-accelerations slowed the bird early in the turn and redirected the CoM centripetally throughout the maneuver. Wingbeat-averaged CoM-accelerations were directed approximately 30° anterior of the vertical body axis, regardless of the bird’s 3D angular orientation. Aerodynamic torques about the pitch axis dominated (~ 200%) over roll and yaw torques throughout the turn and consistently acted ‘head down’ early and ‘head up’ late in both halves of the wing beat cycle. Aerodynamic roll and yaw torques acted for varying durations and at varying phases of the wingbeat cycle, during both downstroke and upstroke. Thus, during turning flight in pigeons, the geometry of the turn and the uniform direction of CoM-accelerations in the body frame appear to necessitate the observed roll, pitch and yaw body rotations. Furthermore, it appears aerodynamic pitch torques are unavoidable and inherent to the flight mechanics, while aerodynamic roll and yaw torques are generated as needed. (NSF IOS-0744056)
