In: International Journal of Intelligent Control Systems, Vol. 3, No. 3, pages 277-295. 1999.
Abstract: This paper presents a Petri net based method for deadlock-free scheduling of flexible manufacturing systems. Potential deadlocks can arise when material handling and buffer space resources are considered in scheduling processes. The deadlock states are explicitly defined in the Petri net framework, so no more equations are used to describe deadlock avoidance constraints to derive deadlock-free schedules. A hybrid heuristic search algorithm which combines heuristic best-first search and near-optimal backtracking search is proposed to generate an optimal or near-optimal deadlock-free schedule. The issues such as deadlock, routing flexibility, multiple lot size, limited buffer size and material handling (loading/unloading) are explored. Interesting results are reported through comparison of the Petri net method and other methods such as mathematical programming and dispatching rules.
Keywords: Petri nets, deadlock-free scheduling, flexible manufacturing systems.