ZMP feedback balance control of humanoid in response to ground acceleration

Abstract

In order for a humanoid robot to balance on the movable ground, balance feedback control in response to its unpredictable movement is required. However, feedback control in response to ground movement has the following two issues, (A) Interaction between the ground dynamics and the balance control may cause vibration. (B) The balance control may rather deteriorate the stability due to the response delay. To solve these problems, this study proposes the support foot acceleration term in the walking stabilizer and gives its gain by considering the following two conditions, (A) Avoiding steady-state vibration in a two-mass linear inverted pendulum model on an arbitrary ground, and (B) reducing the influence of inertial forces resulting from the delay of ZMP feedback. Experiments with a life-size humanoid JAXON verified the steady-state vibration phenomenon and improved the stability of acceleration and deceleration when boarding the Two-Wheeled Scooter.