Balance and impedance control for biped humanoid robot locomotion

This paper describes a locomotion control for biped humanoid robots based on a balance control and an impedance control. The balance control is employed during a whole walking cycle, which can compensate for the moments generated by the biped walking. In the control, the compensatory motion of the trunk and waist is calculated from the trajectories of the lower-limbs, arms, head and ZMP. The parameters of the impedance control are adjusted in real-time according to the gait phase. The large damping coefficient of the impedance is applied to the landing leg to absorb the impact/contact force during the contact phase, while the large stiffness is given to increase the momentum reduced by the viscosity of the landing leg during the first half single support phase. By dynamic walking experiments using a human-like robot WABIAN-RIII, the validity of the proposed control methods is verified.