Design and Analysis of a Flipping Controller for RHex

Abstract

We report on the design and analysis of a controller that can achieve dynamical self-righting of our hexapedal robot, RHex. We present an empirically tuned controller that works reasonably well on indoor surfaces, using a hybrid energy pumping strategy to overcome torque limitations of its actuators. Subsequent modeling and analysis yields a new controller with a much wider domain of success as well as a preliminary understanding of the hybrid control strategy. Simulation results demonstrate the superiority of the improved control strategy relative to the first generation empirically designed controller. RHex is an autonomous hexapod robot that negotiates badly irregular terrain at speeds better than one body length per second [8]. In this paper, we report on efforts to extend RHex’s present capabilities with a selfrighting controller. Motivated by the successes and limitations of an empirically developed “energy pumping” scheme, we introduce a careful multi-point contact and collision model so as to derive the maximum benefit