A three-level net formalism for the modelling of multiple mobile robot systems

This paper deals with the qualitative modelling of multiple mobile robot systems. The approach held is Petri net based: a definition of a three level scheme of Petri nets in which the tokens can be Petri nets is presented. The upper level describes the robots environment, the next level models the general behaviour of the mobile robots, and the third level represents specific features of each robot namely mission, tasks, and roadmaps; at this level it is also described resources and robot interaction protocols. The modelling formalism is illustrated through a case study regarding a mobile robot community evolving into a structured environment.