Dynamic bipedal walking under stick-slip transitions

This paper studies the hybrid dynamics of bipedal robot walking under stick-slip transitions. We focus on two simple planar models with point feet: the rimless wheel and the compass biped. Unlike most of the existing works in the literature that assume sticking contact between the foot and the ground, we explore the case of insufficient friction, which may induce foot slippage. Numerical simulations of passive dynamic walking reveal the onset of stable periodic solutions involving stick-slip transitions. In the case of the compass biped with controlled joint torque actuation, we demonstrate how one can exploit kinematic trajectories of passive walking in order to induce and stabilize gaits with slipping impact.