抄録
The paper considers the methods of modeling and control of discrete event robotic manufacturing systems using Petri nets and proposes a methodology of decomposition and coordination for hierarchical and distributed control. First, a task specification is defined as a Petri net model at the conceptual level, and then transformed to the detailed Petri net representation of the subtasks. Finally, the overall Petri net is decomposed and the constituent subnets are assigned to local Petri net based controllers. The coordinator is introduced to coordinate the distributed controllers so that the behavior of the distributed system is the same as that of the original Petri net. A coordination algorithm by two control levels is developed for defining robot and machine activation conditions. Based on the proposed method, a distributed control system has been implemented for a robotic manufacturing cell.
