Hierarchical Task-Priority Control for Human-Robot Co-manipulation

The extensive distribution of collaborative robots in industrial workplaces allows human operators to decrease the weight and the repetitiveness of their activities. In order to facilitate the role of the human worker during the interaction with these robots, innovative control paradigms, enabling an intuitive human-robot collaborative manipulation, are needed. In this work, a dynamic and hierarchical task-priority control framework is proposed, leveraging a physical interaction with a redundant robot manipulator through a force sensor. The foremost objective of this approach is to exploit the non-trivial null-space of the redundant robot to increase the performance of the co-manipulation and, consequently, its effectiveness. A comparison between the proposed methodology and a standard admittance control scheme is carried out within an industrial use case study consisting of a human operator interacting with a KUKA LBR iiwa arm.