Dynamic balance of a bipedal robot with trunk and arms subjected to 3D external disturbances

This paper deals with a novel approach based on the synergy between the dynamic motions of balancing masses and arms to reject large perturbations applied to the upper part of a bipedal robot. Initially the stabilization is carried out with a trunk having 4 degrees of freedom: three translations and one rotation. In the second time the stabilization is performed with a system with arms and having 10 DOFs. At first, for a vertical posture of the robot, the trunk bodies of ROBIAN are used to compensate the external three-dimensional efforts applied to the robot. During the simulation, this study allows us to determine on-line, the required movements and accelerations of the trunk bodies in order to maintain the robot stability. In the following stage, we study the required movements of a system which is made up of a trunk and two arms in order to ensure the robot stability in presence of disturbances or during a handling of an object. The same formalism is chosen to study the dynamics of the new upper part of the robot. This study shows the importance of the arms for the robot stability.