A decentralized cooperative transportation scheme for humanoid robots

Abstract

We propose an MPC-based decentralized scheme for cooperative transportation between two agents. One agent, the leader, can be either a human or a robot with knowledge of the task. The other, the follower, has no knowledge of the task, and must autonomously decide how to move based on the perceived interaction forces. The robots interact with the object in a compliant way thanks to a hand admittance controller, and the follower continuously adapts its footstep plan in order to accommodate the hand displacement. The combination of these two effects allows the follower to smoothly react to the motion of the leader: it can move omnidirectionally and rotate, as well as accommodate lifting and lowering of the transported object, all while performing obstacle avoidance during footstep placement. We report dynamic simulations on two HRP-4 robots in a number of different scenarios, both when carrying a table and an object with handles.