The body impedance control for walking stabilization of a quadrupedal robot

One of the basic assumptions in the static gait design for a walking robot is that the weight of a leg should be negligible compared to that of body, so that the total gravity center of the robot is not affected by the leg swing. Based on the assumption, the conventional static gait has been designed for the geometric body center of the robot to be inside of the support polygon which consists of each support leg´s tip position. In a case that the leg is relatively heavy, however, while the body center is kept inside the support polygon, the total gravity center of the robot can be out of the support polygon, which causes instability in walking. In this paper, a body impedance control is proposed to make the total gravity center of robot track the pre-designed trajectory of the body center, so that the walking stability is secured even in the case that the leg weight has serious influence on the total gravity center of the robot