Update Procedure for the Supervisory Control of P-Time Event Graphs

Petri nets are a powerful and recognized formalism for the modeling and the analysis of complex manufacturing systems. To deal with systems whose time issues become fundamental, different time extensions of Petri nets have been developed in the literature, each one being associated with a particular application domain. For time critical systems their correctness depends not only on logical considerations but also on the time necessary to perform operations. In this paper, a supervisory control technique for manufacturing systems modeled by P-time event graphs is proposed. It relies on an actualization procedure based on a firing instant approach and the blocked markings identification, whose goal is to update operation durations along particular identified paths. Furthermore, a graph theory based technique aimed at evaluating the performances of the modeled system is proposed.