Petri net based implementation of hierarchical and distributed control for discrete event robotic manufacturing systems

The methods of modeling and control of discrete event robotic manufacturing systems using Petri nets are considered, and a methodology of decomposition and coordination is presented for hierarchical and distributed control. Based on a task specification, the conceptual Petri net model is designed and transformed to the detailed net representation of the subtasks. The overall net model is decomposed and the constituent subnets are assigned to local Petri net based controllers. The controllers are coordinated so that the aggregated behavior of the distributed system satisfies the task specification completely. By the proposed method, modeling, simulation and control of large and complex manufacturing systems can be performed consistently using Petri nets.