Steering a 3D limit-cycle walker for collaboration with a leader

Abstract

This paper presents a control method for steering three dimensional (3D) dynamically walking bipeds that are engaged in cooperative tasks such as object transportation. Towards achieving safe interaction with a leading human (or robot) collaborator, the walking biped is required to exhibit compliance at the port of interaction, while simultaneously adapting its walking pattern in response to the perceived interaction forces. To address these issues, we propose a method that fuses impedance control of the biped's arm with position control of its legs in a way that the biped adaptively modifies its stepping pattern according to the collaborator's intentions. The method is applied on a 3D bipedal robot that is driven in the workspace by a collaborator, whose intention is communicated to the biped through the interaction force.