Good Things Come in Threes: The Impact of Robot Responsiveness on Workload and Trust in Multi-User Human-Robot Collaboration

Human-robot collaboration has the potential of unlocking new manufacturing paradigms thanks to the intro- duction of a robotic architecture in a production chain that involves human workers. A possible innovative declination of this is the use of collaborative robots to enable two workers to concurrently act on the same manufacturing target without causing mutual disturbances. By doing so, the efficiency of the process would be preserved while reducing the production times. This work designs a physical collaborative task that involves two users and one collaborative robot. The users act in the scenario in a concurrent way on the same target object, while the robot physically intervenes in the scene as a mediator by adjusting the position and orientation of the object to accommodate both users at the same time. Through this exper- imental setup, 78 apprentices and teachers of the BAE Systems Academy for Skills and Knowledge Centre were recruited to investigate the users’ perception of the task workload and trust towards the robotic system. Specifically, they performed the same task under two experimental conditions, in which the robot responded to changes in the interaction in a reactive or timed way, respectively. The statistical analysis showed that a timed response of the robot was associated with lower perceived workload and higher predictability of the system.