Dynamics of heel strike in bipedal systems with circular feet

Abstract

Energetic efficiency is a fundamental subject of research in bipedal robot locomotion. In such systems, the collision of the foot with the ground at heel strike is the main cause of energy loss during the gait. In this work, a Lagrangian framework to study the impulsive dynamics of collisions is presented. Based on the inert constraints of this event, a decomposition of the dynamics to the spaces of constrained and admissible motions is introduced. It is used to analyze the energy redistribution at heel strike in circular-feet bipeds. We present results that show the effect of the foot radius and the impact configuration on the energetic cost of walking. © Springer Science+Business Media B.V. 2009.