Stabilization of Unstable Limit Cycles in a Push-off Based Dynamic Walker by Reversible Switching Surfaces

Abstract

By employing the concept of “Reversible Switching Surfaces” (RSS), we demonstrate that it is possible to stabilize unstable periodic orbits of a push-off based dynamic walker. The concept is implemented by a simple event-based control which kinematically controls the foot during the swing phase to adjust the heel-strike. The feedback controller is designed based on the theory of Virtual Holonomic Constraints (VHC). Simulation results demonstrate, there exists a broad range of VHC which satisfies stable dynamic walking.