Safety-Based Task Scheduling Method of HRC Workcells for Automotive Industry

The use of collaborative robot solutions is becoming increasingly significant in the current industrial scenario. These solutions lead to new ways of executing processes by combining the human skills with robot performances. Conversely, an effective cooperation between humans and robots requires an optimal balance between the adopted safety countermeasures and the sequence of production operations, especially in highly automated solutions such as those of the automotive industry. This paper proposes a method to evaluate how the change of the safety level affects the task scheduling. Through a simulation of parallel tasks performed by human and robot, this approach identifies the optimal task scheduling which minimizes the production time for a fixed safety level. As a test case, the collaborative polishing process of moulds for the production of automotive parts, involving an industrial manipulator and an operator, is presented. The results prove the existence of a preferable sequence of the operations for a fixed safety level and a direct relation with the balancing of operator and robot workloads.