Robust Control of Dynamic Walking Robots Using Transverse H∞

Abstract

The control of walking robots has been a long-studied problem as researchers attempt to bring robots out of the lab and into unstructured environments. In particular, there is significant interest in dynamic walkers: a class of walking robots that exhibit highly efficient gaits, but are sensitive to disturbances. This paper develops robust controllers for dynamic walkers in transverse coordinates using H∞ control, with a focus on rejecting disturbances at foot impact. The optimization objective is a measure of disturbance rejection known as the gait sensitivity norm. The controller was used to stabilise a compass gait walker in simulation for various disturbances. Simulation results demonstrate the advantages of phase-tracking and H∞ control for robustness compared to time-varying and LQR controllers.