Adaptive Four Legged Locomotion Control Based on Nonlinear Dynamical Systems

Abstract. Dynamical systems have been increasingly studied in the last decade for designing locomotion controllers. They offer several advan-tages over previous solutions like synchronization, smooth transitions under parameter variation, and robustness. In this paper, we present an adaptive locomotion controller for four-legged robots. The controller is composed of a set of coupled nonlinear dynamical systems. Using our controller the robot is capable of adapting its locomotion to the phys-ical properties of the robot, in particular its resonant frequency. Our approach aims at developing an on-line learning system that attempts to minimize the energy necessary for the gait. We have implemented the model both in a simulated physical environment (Webots) and on a Sony Aibo robot. We present a series of experiments which demonstrate how the controller can tune its frequency to the resonant frequency of the robot, and modify it when the weight of the robot is changed.