SLIP-SL: Walking Control Based on an Extended SLIP Model with Swing Leg Dynamics

Abstract

This paper details an extension to the SLIP model named spring loaded inverted pendulum model with swing legs (SLIP-SL). SLIP-SL extends the SLIP model by introducing swing leg dynamics while keeping its passive nature. This way, reference trajectories for the center of mass and swing foot trajectories can be simultaneously obtained which was not possible with the SLIP. This makes implementation easier and can increase tracking performance. We show how a variety of feasible two-phased walking trajectories can be obtained for this template model using direct collocation optimization methods. It is also shown through simulation studies that reference SLIP-SL trajectories can be used to control a fully actuated bipedal robot with the proposed feedback linearization controller to reach a stable cyclic gait.