Time-domain passivity control based stabilization control of humanoid robot for walking on inclined plane

Abstract

In this thesis, the novel stabilization control method of humanoid robot is proposed for a stable dynamic walking. It should be noted that online walking control is indispensable to obtain a stable dynamic walking even if the walking pattern is made based on zero moment point (ZMP) and angular momentum. A reason is that disturbance and errors, which are not expected in the modeling stage, can exist in the actual condition. Therefore, this thesis proposes the stabilization control scheme that takes both landing force control and posture control into account. In addition to the stabilization controller, the walking pattern generation method considering inclined plane is also proposed. Though walking pattern is made by considering a ground reaction force, this ground reaction force does not act on the robot at expected time and as expected magnitude due to various errors. This force accelerates or rotates robot`s center of gravity and alters the expected robot`s ZMP and angular momentum, which results instability. Thus, reducing landing force is one of the important factors for stable walking and the landing force control algorithm is proposed for this objective. In this thesis, time-domain passivity control approach is applied. Ground and robot`s foot are modeled as two one-port network systems, which are connected and exchange energy with each other. The time-domain passivity controller with admittance causality is implemented where the landing force is given as an input and the corresponding foot position is assigned as an output to trim off this force. Second major part of the stabilization control method is posture control. It is required to compensate unexpected inclination of robot`s posture, which is caused by various disturbances and errors. Posture control algorithm is also implemented by using time-domain passivity approach. It controls robot`s posture according to resulted torque and an inclination of robot. Similar to the landing force control, ...