Effects of hand contact on the stability of a planar humanoid with a momentum based controller

This paper studies the effects of hand contact force on the stability of a planar humanoid robot while translational perturbations are applied to its foot. A momentum based controller is used to control the robot´s motion during the perturbations. Simulation results show that the displacements of the center of pressure (CoP) of the foot decrease substantially when there is a supportive contact between the hand and the environment. The simulation results of the CoP displacements and handle forces also conform with the results of the experiments on human subjects with different positions of the hand contact. This conformity shows that the momentum based controller adequately models human behaviour in contact with the environment during a balancing motion.