Muscular Coactivation to Evaluate the Ergonomic Impact of Human-Robot Collaboration in Manual Handling Tasks

Interaction with collaborative robots is rapidly increasing, especially in the industrial sector. This widespread adoption demands a comprehensive evaluation of its impact on workers, to ensure that their presence does not compromise safety and ergonomic quality of movement execution, while also uncovering potential benefits. This paper presents an experiment designed to assess these effects, focusing on the analysis of muscular involvement during manual handling tasks performed in collaborative scenarios with an 8DOF robotic arm. The experiment was conducted under two distinct conditions: unassisted execution and execution in the presence of a collaborative robot and external agents providing instructions. Surface electromyography (EMG) activity of sixteen upper limb and trunk muscles was recorded to extract indicators of individual muscle activity and indices of group-level coactivation. A comparison of coactivation levels between the two task conditions suggests that the presence of the collaborative robot and external instructions results in more efficient and ergonomically favorable behavior, potentially reducing biomechanical risk for workers.Clinical Relevance- While the results are preliminary and do not directly target a population of clinical interest, the study may be of clinical interest in the future if the indicators of muscular coactivation can be linked to the development of work-related musculoskeletal disorders.