Scheduling of FMS based on binary decision diagram and Petri net

For flexible manufacturing systems (FMSs), this paper presents a symbolic and intelligent approach to obtain optimal schedule paths by combining reduced ordered binary decision diagrams (ROBDDs) and intelligent search techniques based on the Petri net (PN) models. First, FMSs are modeled via place-timed PNs which contain processing time information on activity places. Then, a ROBDD technique is given to represent the evolution of such nets and the A∗ search on their reachability graphs. ROBDDs can represent large sets of data with compact shared structures and allow the efficient computation on those sets. Thus, the proposed approach is efficient in finding scheduling paths for FMSs.