3D dynamic walking based on the inverted pendulum model with two degree of underactuation

Abstract

In this paper, the new control method to realize 3D natural dynamic walking based on the 3D robot inherent dynamics is proposed. The proposed method describes robot dynamics by use of a 3D inverted pendulum model and applies passive dynamic autonomous control (PDAC) to it. By utilizing the polar coordinate system to express the robot state around the contact-point between robot and the ground and applying PDAC, it is possible to express the 3-dimensional dynamics as 1-dimensional autonomous system. Due to autonomy, this 1D dynamics has the conservative quantity named PDAC constant. We build the stabilizing controller by means of PDAC constant and analyze the walking based on the 1D dynamics. Finally the proposed method is tested by experiment.