A simple legged locomotion gait model

Abstract

Significant advances have been occurred over the past two decades in issues related to the mechanical design of legged robots and the coordination and control of legs during locomotion. The performance of current legged robots, however, remains far below even their most simple counterparts in the biological world. Naturally, this has lead to a search by researchers for biologically motivated principles of design and control which might lead to improved performance and robustness. In this paper, the role of central pattern generators (CPGs) in locomotion is studied. In contrast with previous approaches, we suggest the use of a single pattern generator whose output is connected to motor neurons (servo controllers) through neural pathways (cables) that generate the time delays characteristic of various gaits. A mathematical model for such a scheme is developed and a simple algorithm for encoding the characteristic gaits of bipeds, quadrupeds and hexapeds is presented. The paper concludes with a description of ongoing experimental work on a hexaped robot.