Core-centered actuation for biped locomotion of humanoid robots

In this paper we examine a novel method of core-located actuation that we believe can be used to vary gaits in a compass-gait walker, using critical analysis of a ball-in-tray mechanism to apply forces at the robot's "pelvis". The dynamic equations of motion of a tilting ball-tray system with several design parameters are developed and simulated for various tray designs. Results show that changes in tray design do indeed significantly affect the trajectory. When compared to a hardware ball-tray system, the results show good agreement with the simulation. The sagittal plane component of the ball's trajectory is applied to the motion of a corresponding mass at the "pelvis"of a compass-gait walker. Simulations of the compass-gait walker show that this trajectory generates a feasible gait.