Petri Nets based coordination of flexible autonomous guided vehicles in flexible manufacturing systems

This paper presents the Petri nets based approach used to coordinate several flexible automated guided vehicles (AGVs) operating in flexible manufacturing systems (FMS). The on-board path planning and the way to configure the vehicles are the main features that differentiate flexible AGVs from traditional ones. These new characteristics enable them to recalculate routes for avoiding non-modeled obstacles and reconfigure themselves easily by the definition of workplace after layout changes. In order to allow that the vehicles operate as a team, the coordination is based on threefold: i) task allocation under workcells demand, ii) Petri nets based task execution for traffic control, and iii) collision-free motion based on replanning and a control policy for safety navigation. The interaction of some vehicles operating in the same area has been tested in a real industrial setting.