Extension of the supervision concept to the monitoring of discrete event systems

This paper deals with the extension of supervision concept to monitoring discrete event systems (DES) to resolve the forbidden concepts based on controlled objects Petri nets. The synthesis of control in nominal functioning (supervision) is based on the forbidden state conditions, and an risk state conditions in degraded functioning (monitoring). After a brief presentation of the forbidden state problems in DES, the paper describes the supervision structure used and the control policy adopted in nominal functioning. It also presents the extension of the supervision concept to the monitoring and the control policy adopted in degraded functioning. The practical application of the theoretical results is illustrated using an example of flexible manufacturing systems.