Cognitive Ergonomic Challenges in Human-Cobot Assembly: Exploratory Laboratory Test Findings

The design process of human-oriented collaborative workstations must balance production performance with workers' psychophysical well-being and safety. Cobots enable the reduction of physical effort and hazardous tasks, favoring human efficiency in value-added activities. Nevertheless, the interaction between humans and cobots can generate side effects on mental strain, cognitive effort, and motivation, reducing the performance expected from collaborative setup deployment. Aiming to assess the cognitive stress developed in human-robot collaboration, this exploratory study proposes three laboratory scenarios with increasing interaction between the two entities (i.e., Independent, sequential and supportive). Biological parameters were monitored in real-time to evaluate participants' physiological performance. The combination between decreased heart rate related features (RR distances for intra-operator comparisons and RMSSD for inter-operator comparisons) and increased number of electrodermal activity peaks suggested emotional arousal and/or physiological stress in presence of the cobot for the operator with lower confidence. Self-reported state and quantitative physiological signals for stress detection (i.e., heart rate variability and electrodermal activity) were analyzed to determine the correlation between interaction levels and cognitive ergonomics. Additionally, this research proposes a Human Digital Twin framework that includes real-time cognitive assessment from biological parameters to dynamically adapt collaborative robots' modalities according to the abilities and confidence level of the co-worker.