Flexible scheduling and tactile communication for human–robot collaboration

Human–robot collaboration (HRC) is expected to add flexibility and agility to production lines in manufacturing plants. In this context, versatile scheduling algorithms are needed to organize the increasingly complex work-flow and to exploit the gained flexibility, ensuring the optimal use of resources and the smart management of failures. Moreover, intuitive user interfaces are needed to communicate with the human worker, informing him/her of the next operation to perform. Usually, grounded or wearable screens are used to this aim. Whenever human sight is impaired or needs to be free, other sensory channels could be used as well. In this work, we present a new dynamic scheduler that adapts to the system variability, and a novel way of communicating instructions to the human operators based on haptic guidance. The proposed strategies were applied to a complex assembly task involving three agents and compared to baseline methods with an experimental campaign involving 16 subjects. Results show the clear advantage of using dynamic scheduling over the static one and suggest that a combination of visual and tactile stimuli is a viable and effective solution for displaying instructions in complex HRC scenarios.