Motion Coordination of AGV's in FMS using Petri Nets

This paper proposes a modeling strategy for automated Flexible Manufacturing Systems (FMS) that incorporates automated guided vehicles (AGV's) as material handling systems. Using the industrial standard ISA-95, the task-based coordination of equipment and storages is constructed considering process restrictions, logical precedence conditions, shared resources and the assignment of the robots to move work pieces individually or in subgroups. The Petri Net model calls in the low level to formation, marching and collision avoidance control laws, for omnidirectional robots. The hybrid architecture is implemented and validated for the case of a FMS and four mobile robots.