Robustness of supervisors for discrete-event systems

Supervisory control in the context of /spl omega/-languages is considered. The nominal supervisor design problem is to find a non-blocking supervisor for a nominal plant such that the closed-loop infinite behavior equals a specified closed-loop behavior. The robustness of solutions to the nominal problem is defined with respect to variations in the plant. It is shown there exists a supervisor solving the nominal problem which maximizes the set of plants for which the closed-loop languages for all other plants in the set satisfy lower and upper bounds in the sense of language containment. Computational issues are discussed and the theoretical results are illustrated with an example.