New insights into quasi-static and dynamic omnidirectional quadrupedal walking

Abstract

This paper presents several new insights and experimental results on the problem of generating omnidirectional walking gaits for quadrupedal robots. For statically stable gaits, by placing some minor restrictions on how the leg motions are generated, we develop an easily computable classification of the best gait patterns (leg phasings) to be used for any given motion. This simple geometric construction allows easy generation of stable, omnidirectional walking gaits for any quadruped satisfying only some very weak assumptions about the location of the center of mass relative to the workspace of the legs. It is also well-suited to a modular approach in which the control of individual legs is decentralized. We also implement an omnidirectional dynamic trot gait using a similar approach. Transitions involving a change in the direction of motion of the robot are initiated at one of two fixed points of the foot placement curves for each leg in all gaits. Experimental data is presented showing the effectiveness of these techniques.