1992 Volume 112 Issue 4 Pages 377-386
An on-line FMS scheduling system, which takes in consideration the routing flexibility is proposed in this paper. The FMS is modeled utilizing a Timed Petri net representation. This representation provides real time information about the production evolvement and the status of each machine and equipment. With this information the proposed system starts to search for the scheduling of the next orders to be assigned. The search is performed by a beam search based on-line decision method. The developed algorithm, integrating the Timed Petri net representation to the beam search, is described. To test the developed system Just-in-Time production objective was established. The performance of the system is evaluated through exhaustive simulations. The achieved results are very promising, as the proposed system leads not only to a better achievement of the production objective, but also to smaller variance under different scheduling conditions, suggesting greater reliability.