Non-blocking step state-feedback supervisory control of discrete event systems using interpreted Petri nets

This paper deals with supervisory control of Discrete Event Systems (DES) by state feedback in order to avoid uncontrollable specifications and blockings. It incorporates two levels of modeling that includes the system and specification model and secondly the interpretation of the specification model in term of the system model based on trace equivalence. Next the controller process is computed. In this approach the specification and the system model are described by Interpreted Petri nets (IPN), and the specification describes a state subset that the specification must reach. It also captures the order, in which these states must he reached. The method to interpret the specification language in term of the system language includes structural information of both IPN (system and specification) to define trace equivalence, which to avoid blocking and uncontrollability. Moreover, this work presents a technique to modify trace equivalence based on the inclusion of uncontrollable events to guarantee controllability (compute of the infimal controllable language).