Evolution of communication-based collaborative behavior in homogeneous robots

In the field of collective robotics much research has been de- voted to the study of coordinated and cooperative behaviours where typically all the robots play the same function. Much less attention has been devoted to the development of groups of robots that play different roles (robot teams), probably be- cause evolutionary collective robotics tend to use groups of homogeneous robots, in which role differentiation poses dif- ficult challenges. In the few Evolutionary robotics studies in which role differentiation has been demonstrated such differ- entiation depends exclusively on the robots physical interac- tions, making the solutions found by evolution quite fragile, in particular with respect to the number of robots that form the group. In this paper we apply a method for role differentia- tion developed in previous work to the evolution of teams of homogeneous robots in which role differentiation is based on a dedicated communication channel. Our evolved robots are able to negotiate their role through communication and per- form very effectively their collaborative task, which requires that one robot is sent to a 'mission' away from the group while all other robots remain in a 'home'. Our simulations also show that the method proposed, based on the reward- ing of communication-based role differentiation, is necessary for the evolution of the desired behaviour. Finally, we show that since role differentiation is based on communication and not only on robot physical interactions, evolved solutions are considerably robust with respect to the number of robots com- posing the group.