Energy based limit cycle control for elastically actuated biped robots

Abstract

Legged robots are challenging systems to control due to their hybrid nature, underactuation and unilateral constraints. To perform highly dynamic tasks as jumping and running, performant actuators are required. Elastic joints are often used, but they introduce another source of underactuation in the system. Since locomotion patterns can be described as periodic tasks, in this work controllers are designed to produce asymptotically stable limit cycles by regulating the energy of the system. Different control laws are proposed, both for rigid and elastic joints, with applications to biped locomotion.