Bang-Bang Trajectory Plans With Dynamic Balance Constraints: Fast Rotational Reconfigurations for RoboSimian

This paper investigates the problem of rapidly transitioning the pose of a limbed robot while remaining balanced. In particular, we consider motions where rotational accelerations may significantly affect the center of pressure location within a limited base of support. We consider solutions for high-impedance robots with stiff, high-torque actuators that essentially provide accurate, position-control outputs at the joints. We present and compare three methods for generating joint trajectories to achieve fast yet feasible dynamic motions for such systems while maintaining a safety margin for the center of pressure location, toward robust balance. We focus on development of theory and intuition for each method and quantify performance in terms of achievable speed of transition and required joint velocity limits.