Dynamic Distribution of Assembly Tasks in a Collaborative Workcell of Humans and Robots

Collaborative robots belong to the enabling technologies of Industry 4.0. They allow the set-up of semi-automatic workcells where robots and humans collaborate in the execution of complex tasks, with unprecedented flexibility if compared with standard robotic cells. This paper addresses some of the many issues that arise from introducing in the factory, not only a new workcell, but also a new working paradigm. The study considers the introduction of collaborative robots in a small production workcell. To increase the chances of success of the new cell, it proposes a method for firstly assigning tasks to human and robotics operators, based on the task characteristics and operator abilities, and then dynamically reassigning tasks to overcome disturbances or delays at the shop floor level. The justification of the method is that outages are frequent in small non-standardized productions, therefore offline optimized task assignment could be ineffective. The method is tested against an industrial case study and the results are discussed.