Weak normality for nonblocking supervisory control of discrete event systems under partial observation

In this paper, we study nonblocking supervisory control of discrete event s ystems under partial observation. We introduce a weak normality condition d efined in terms of a modified natural projection map. The weak normality co ndition is weaker than the original one and stronger than the observability condition. Moreover, it is preserved under union. Given a marked language specification, we present a procedure for computing the supremal sublanguag e which satisfies L-m(G)-closure, controllability, and weak normality. Ther e exists a nonblocking supervisor for this supremal sublanguage. Such a sup ervisor is more permissive than the one which achieves the supremal L-m(G)- closed, controllable, and normal sublanguage.