Motion Planning for Humanoid Locomotion: Applications to Homelike Environments

"What can your humanoid robot do?"is probably the most commonly asked question that we, as roboticists, have to answer when interacting with the general public. Often, the question is framed in the familiar household or office setting, with implied expectations of robust locomotion on uneven and cluttered terrain and compliant interaction with people, objects, and the environment. Moreover, the question implies the existence within the humanoid robot of a set of embodied loco-manipulation skills implemented by a motion planner, skills that are retrievable when given the corresponding commands. In this article, we formulate an answer to this question in the form of an efficient, modular, and extensible motion planner. We demonstrate its use with three challenging scenarios, designed to highlight both the robot's safe operation and its precise movement in unstructured environments. Additionally, we discuss key techniques derived from our experience in the practical implementation of torque-controlled humanoid robots.