How Can We Understand Multi-Robot Systems? a User Study to Compare Implicit and Explicit Communication Modalities

In this paper we investigate the use of different communication modalities for a multi-robot system. Specifically, the aim is to let a human subject be aware of the goal robots are moving towards: to this end, we compare implicit (i.e., the user infer robots goal from their motion pattern) and explicit (i.e., using visual or audio clues) communication modalities. We propose a user study, performed in virtual reality, aimed to assess which communication modality is the most effective and how they are perceived by human subjects. While implicit communication has the intrinsic advantage of not requiring any specific hardware on the robots, results of the user study show that implicit communication is comparable, from the users’ perspective, to explicit communication modalities when robots goals are unambiguous and sufficiently distinct. In other cases, explicit communication is preferable.