Dynamics in the dynamic walk of a quadruped robot

Abstract

Walk can be classified as 'static walk' and 'dynamic walk'. It is said that dynamic walk is superior in both speed and energy consumption. This paper describes how a quadruped robot should walk dynamically to realize these advantages. Such consideration is lacking in past research. In this paper, three criteria are introduced to evaluate the walk-'stability', 'maximum speed', and 'energy consumption'. The relations between these three criteria and the parameters (gait, speed, period, stride, length of the leg, joint angles, etc.) are formulated accordingly to the dynamics. The conclusions are as follows: (1) The shorter a period is, the more stably the quadruped can walk. (2) It is desirable to walk with a longer period and wider stride in order to increase the maximum speed. (3) There is a period which maximizes the speed. (4) There is a period which minimizes the energy consumption for a given speed. (5) Trot gait is desirable when the priority is placed on energy consumption. Pace gait is recommended when the priority is placed on maximum speed. From experiments using the quadruped robot Collie-2, the validity and usefulness of these relations are verified.