Dynamics and stability of insect locomotion: a hexapedal model for horizontal plane motions

We develop a simple hexapedal model for the dynamics of insect locomotion in the horizontal plane. Each leg is a linear spring endowed with two inputs, controlling force-free length and "hip" position, in a stereotypical feedforward pattern. These represent, in a simplified manner, the effects of neurally activated muscles in the animal and are determined from measured foot force and kinematic body data for cockroaches. We solve the three-degree-of-freedom Newtonian equations for coupled translation-yawing motions in response to the inputs and determine branches of periodic gaits over the animal's typical speed range. We demonstrate a close quantitative match to experiments and find both stable and unstable motions, depending upon input protocols. Our hexapedal model highlights the importance of stability in evaluating effective locomotor performance and in particular suggests that sprawled-posture runners with large lateral and opposing leg forces can be stable in the h...

• Type: Journal
• Year: 2004
• Where: BC
• Authors: Justin E. Seipel, Philip J. Holmes, Robert J. Full
• Keywords: BC 2004, Hexapedal Model, Horizontal Plane, Simple Hexapedal Model