Human-Humanoid Robot Cooperative Load Transportation: Model-based Control Approach

Abstract

In order to properly integrate humanoid robots in real-life situations, they must be able to collaborate with humans in completing tasks. One of these tasks is the cooperative transportation of a heavy object, which has been widely studied in the humanoids literature. However, the proposed methods rely heavily on six-axis force/torque (F/T) sensors at the wrists, which medium-sized or even some full-sized humanoid robots do not have. This paper proposes an observer to overcome the lack of F/T sensors. The observer is then coupled with a simplified dynamic model of the transportation task allowing the humanoid robot to carry out the task in a stable way. The method is tested in simulation using a humanoid robot that does not have F/T sensors, a NAO robot, to demonstrate its performance. These tests pointed out that the proposed method successfully estimated the interaction forces while generating stable walking patterns.