Maneuvering operations of the quadruped walking robot on the slope

Abstract

On the assumption that a quadruped robot works on a slope, we discuss how to make it prevent tumbling over. The larger the difference becomes between the potential energy of the center of gravity of the initial position and that of the highest position after its rotating, the less the robot tumbles. So this difference can be regarded as stability margin, and a novel gait to obtain largest stability margin is mentioned here. It is an intermittent crawl gait. Its energy stability contour (consisting of equal stability points on the inclined plane) is helpful in the design of standard foot trajectories. An optimal posture on the slope, designed in this way, results in inverse trapezoid shape, which means that upper two legs are located wider than lower two ones. This form worked for the experimental machine, TITAN VII. Furthermore, if the standard trajectory for one direction is combined with another direction trajectory, the quadruped robot can easily switch its proceeding directions, keeping enough stability margin. This sequence is shown.