Walking stabilization of biped with pneumatic actuators against terrain changes

Humans are supposed to utilize its joint elasticity to realize smooth and adaptive walking. Although such human-like biped walking is strongly affected by the terrain dynamics, it was not taken into account in robotic bipedalism since it is very difficult to model the dynamics formally. In this paper, instead of modeling the dynamics formally, we propose to estimate the relationship between actuation (air valve opening duration) and sensing (touch sensor information) by real walking trials, and to stabilize walking cycle by utilizing it. Since the terrain dynamics is involved in the relation, we can avoid to model it formally. We conducted walking experiments on various types of terrain to demonstrate the effectiveness of the proposed method.