Maximal output admissible set for trajectory tracking control of biped robots and its application to falling avoidance control

Humanoid robots have been considered as a universal machine which can operate in place of human. This kind of universal machine requires human-like biped walking capability. In particular, it is important to avoid falling by appropriately switching behaviors even if there are unknown disturbances. The authors proposed the maximal output admissible (MOA) set for the center of gravity (COG) regulator in the upright position. Based on the MOA set, we can switch feedback gains with the Zero Moment Point (ZMP) constraint satisfied. In this paper, the author extends MOA set framework to trajectory tracking controller. This extension makes it possible to switch controllers: regulator in the upright position and tracking controller of a stepping motion in order to avoid falling. The effectiveness of the proposed method is verified with a simulation.