Development and validation of guidelines for safety in human-robot collaborative assembly systems

Industrial collaborative robotics is one of the most promising technologies of Industry 4.0. In particular, human-robot collaboration in assembly will be particularly interesting for manufacturing companies. In this context, the interaction between humans and robots opens new possibilities but also challenges. A major problem is related to safety: unwanted and unexpected contacts between the human and the robotic system may cause injuries and therefore limit the potential for collaboration. Nowadays, there is a lack of simple and practical tools for helping system designers in overcoming such limiting conditions. In this work, guidelines for the design of safe human-robot collaborative assembly are developed and classified, particularly focusing on the features characterizing the entire system. These are validated by means of a laboratory case study and a digital twin. The validation process is based on the assumption that a team of manufacturing engineers (not-experts in occupational health and safety) should be able to autonomously and gradually apply the given guidelines reducing the mechanical risk in a collaborative assembly system. The proposed solutions have been virtually modelled allowing the evaluation of their effectiveness. According to the results, the proposed guidelines effectively help non-expert users in the development and improvement of collaborative assembly systems from the safety perspective.