Tools for the design of stable yet nonsteady bounding control

Abstract

Control efforts on dynamic gaits for legged systems traditionally focus on limit cycles and their stability. However, there are many practical situations where step-to-step variability is highly desirable, for example to achieve variable footholds or to recover and replan after perturbations. In this paper we present an effective, high-level switching control framework for overcoming terrain obstacles using the familiar A* algorithm to search a mesh over the reachable space for a given set of controllers. In support of this, we present new low-level control strategies for generating stable bounding with planar models of a spring-legged quadruped robot, and demonstrate their use crossing gaps in the terrain.