P-time Petri nets and the hoist scheduling problem

Presents the ability of a new Petri net tool to face a kind of industrial problem. These problems are characterized by operating times included between a minimum and a maximum value. The considered application is an electroplating line for which the carrying resources must be free at a time which is compatible with the treatment durations. The first step is the modeling of these specifications. The second step is devoted to the search of a sequencing of the hoist compatible with the objective and the staying time constraints of the parts in the treatment baths. The third part consists in determining a local control: the beginning and the ending instants of each treatment. This class of problems is known as the "hoist scheduling problem". We focus on the repetitive functioning mode.