Trajectory design and control of edge-landing walking of a humanoid for higher adaptability to rough terrain

The present paper proposes a walking control of a humanoid that uses heel and toe edge landing for better adaptability to rough terrain. We focus on the control of forward straight walking and the roughness, such as changes in level and inclination, along the walking direction is explicitly considered herein. The requirements for designing the walking parameters, such as the step length and the step cycle for continuous walking, are discussed based on assumptions on the roughness of the terrain. An online adaptation strategy that includes change in stepping length, step cycle, and landing edge is discussed. The adaptation strategy uses the actual center of mass motion and the contact status to the ground for changing the stepping length, the step cycle, and the landing edge. We extended a walking pattern generation method that can handle the permissible region of the ZMP for balance recovery to a version that can also simultaneously handle changes in stepping position if needed. This method is used in the abovementioned discussions. A compensation method for the effect of the multibody system is also presented, so that these discussions can be made applicable to the actual humanoid system.