Evaluation of Variables of Cognitive Ergonomics in Industrial Human-Robot Collaborative Assembly Systems

In the context of Industry 4.0, a human-robot collaborative assembly system is an example of a cyber-physical production system, where operators and robots interact during assembly. Considering the growing market and the increasing use of industrial collaborative robotics, companies need support in the proper and profitable introduction of this technology in their production environment. From a design standpoint, it is necessary to develop safe and ergonomic interactions between the operator and the system, primarily focusing on operators’ needs and characteristics of the robot. When designing collaborative systems and workstations, human-factors and cognitive requirements are often underestimated or ignored, even if they are crucial for the operator’s wellbeing and production performances. Considering this gap, the present work aims to evaluate cognitive ergonomics variables in human-robot collaborative assembly systems. Three different scenarios of human-robot collaboration have been developed based on the analysis of the scientific literature. The effectiveness of the scenarios has been validated through multiple experiments based on a laboratory case-study where operators physically interacted with a low-payload collaborative robot for the joint assembly of a workpiece. Multiple cognitive variables have been identified and evaluated by gradually changing the workstation elements as well as the conditions of human interaction with the robot. Preliminary results showed the impact of each scenario in reducing the operator’s stress and cognitive workload while improving the operator’s trust, acceptance, and situation awareness.