Relationship between Observability and Normality in Supervisory Control

Abstract

In this paper, we study the relationship between observability and normality arising in supervisory control of discrete event systems under partial observation. We prove that observability together with a condition on unobservable events is equivalent to normality in the presence of controllability. This result means that a supervisor synthesized for the supremal controllable and normal sublanguage of a specification language is a maximally permissive one under a restriction that no unobservable event is disabled.