Inferring forces from kinematics in animal locomotion


Meeting Abstract

P2-202  Tuesday, Jan. 5 15:30  Inferring forces from kinematics in animal locomotion QUINN, D.B.*; LENTINK, D.; Stanford University; Stanford University dbq@stanford.edu http://www.danbquinn.com

The aerodynamic forces and torques that birds create to fly can be inferred from body kinematics if the mass distribution of the bird is known. This method of “inverse dynamics” has been used in several in vivo studies to estimate the aerodynamic loading from the tracked positions of body, wing, and head elements. Without a way to cross-reference forces, however, it has been difficult to estimate the accuracy and precision of these force/torque results. We present the first rigorous analysis of uncertainty in inverse dynamical models of flying birds by comparing estimated forces/torques on a pacific parrotlet, Forpus coelestis, with forces calculated via alternate methods. In addition, we examine the precision of the technique via a comprehensive study of error propagation. Scaling the methods with wingspan gives constraints on the spatial and temporal resolutions required for studying the dynamics of other birds such as lovebirds, pigeons, and hummingbirds.

the Society for
Integrative &
Comparative
Biology