The simplest creeping gait for a quadruped robot

Abstract

This article presents the simplest creeping gait (creeping gait with one center-of-gravity movement in a cycle) for a quadruped robot. The creeping gait with one center-of-gravity movement is efficient in reducing the complexity of gait planning and the control of quadrupeds. To find the simplest creeping gait, the geometrical model of a quadruped is constructed, and the omni-directional stability margin is derived to determine the stability. Based on the features of creeping gaits, the simplest possible gait is analyzed. The mathematical description is used to describe the simplest gait with the maximum omni-directional stability margin. Details of the creeping gait, including its initial pattern and its sequences, are provided. In a cycle of the creeping gait with one center-of-gravity movement, the center of gravity needs to move only once. Only 16 commands are required to move a quadruped with two degrees of freedom in each leg. An experiment conducted on the THU-WL robot proves that the gait is reliable and stable. The creeping gait with one center-of-gravity movement is a remarkable simplification for the creeping gait.