Virtual-mass-ellipsoid Inverted Pendulum Model and Its Applications to 3D Bipedal Locomotion on Uneven Terrains

It is still an open problem to develop a reduced order model of bipedal walking that closely represents the complex dynamics of humanoid robots. In this paper, we propose control methodologies, removing both the constant CoM height constraint and the constant centroidal angular momentum constraint. We define a capturability criterion. and propose an enhanced intrinsically stable model predict control to fulfill this new capturability criterion. Then the angular momentum can be controlled. The results of simulations using humanoid robot HRP-4 show the proposed methods can improve the stability of bipedal locomotion on uneven terrains.