FMS scheduling based on timed Petri net model and RTA* algorithm

Presents a scheduling method for a manufacturing system based on a timed Petri net model and a reactive fast search algorithm. The following two typical problems are addressed in the paper. (1) Minimize the maximum completion time. (2) Minimize the total deadline over-time. As for problem (1), a search algorithm which combines RTA* and a rule-based supervisor is proposed. Since both RTA* and the rule-based supervisor can be executed in a reactive manner, machines and AGVs allocations can be scheduled reactively, and simultaneously. As for problem (2), the original Petri net model is converted to its reverse model and the algorithm developed in problem (1) is applied with regard to the due time as a starting time in the reverse model.