Passivity-Based Control Strategy for Humanoids

Abstract

This chapter covers passivity-based controls for humanoid robots. Passivity-based control has advantages over general active controls that require a large amount of energy consumption while the amount of energy that they carry is limited. First, passivity-based control is reviewed. Euler-Lagrange systems, examples of which are humanoid robots, and their passivity are described. Analysis on passive bipedal walkers is done based on the impact model for the contacts between the swing leg and the ground. This covers how a Poincaré map can be used in finding stable passive locomotion conditions. The concept of the passive bipedal walker is further expanded to an active control of a humanoid robot in order to give it more adaptability to its changing environment. A passivity-based control that has the adaptability of the ground slop and a simple passivity-based active control that increases the attraction basin of the limit-cycle of locomotion for more robustness are described.