Precision Circular Walking of Bipedal Robots

Abstract

Whenever bipedal robots need to make turns, the ability to walk stably and precisely along a circular curve of an arbitrary radius will be quite beneficial. This motivates us to derive new Zero Moment Point (ZMP) constraint equations with respect to a rotating coordinate frame, seek appropriate dynamic gaits based on them, and address the forward and inverse kinematics. After the relevant body and feet trajectories are fully prescribed, joint motions are determined using the inverse kinematics. A set of dynamic walking patterns including the transient are herein proposed and applied to an exemplificative case of turning locomotion. Conclusively, dynamic simulations prove the patterns to be successful even in the presence of distributed-mass and ground contact effects.