Decomposition of Time Petri Nets for Solving Optimal FiringSequence Problem

Petri net model is a frequently-used versatile tool which can represent a widely discrete event system. However, when the scale of the system becomes large, the calculation time for solving optimal problem (optimal firing sequence problem) is markedly increased. In this paper, we propose an approximation method that achieves the efficiency improvement of the solution by decomposing the Petri net for solving the optimal firing sequence problem. A timed Petri Net is decomposed into several subnets in which the optimal firing sequence for each subnet is solved by Dijkstra’s algorithm in polynomial computational complexity. The effectivity of the proposed method is verified by numerical experiments for the flowshop schedule problem.