Human-in-the-loop Robotic Manipulation Planning for Collaborative Assembly

Abstract

This paper develops a robotic manipulation planner for human-robot collaborative assembly. Unlike previous methods which study an independent and fully AI-equipped autonomous system, this paper explores the subtask distribution between a robot and a human and studies a human-in-the-loop robotic system for collaborative assembly. The system distributes the subtasks of an assembly to robots and humans by exploiting their advantages and avoiding their disadvantages. The robot in the system will work on pick-and-place tasks and provide workpieces to humans. The human collaborator will work on fine operations like aligning, fixing, screwing, etc. A constraintbased incremental manipulation planning method is proposed to generate the motion for the robots. The performance of the proposed system is demonstrated by asking a human and the dual-arm robot to collaboratively assemble a cabinet. The results showed that the proposed system and planner are effective, efficient, and can assist humans in finishing the assembly task comfortably.Note to Practitioners-This paper was motivated by assembling a cabinet. The assembling process involves several pick-and-place, reorientation, regrasp, alignment, peg-in-hole, and screwing subtasks. The system distributes these subtasks to robots and humans by exploiting their advantages and avoiding their disadvantages. The robot used is a dual-arm robots with two parallel grippers. Thus, a suction cup tool is used for the pick-and-place of thin objects. Soft-finger contact constraints are considered to assure safe manipulation. Human ergonomics are included as a quality for optimizing the handover between robot arms and robot and human. The proposed planner and system show satisfying user experience and expedite the cabinet assembly. It is expected to help relax the labor-intensive manufacturing process in the future.