Using predicate transformers for supervisory control

A methodology is outlined for designing controllers for a wide variety of systems described in terms of a set of predicate transformers. Predicates have the advantage that they can concisely characterize an infinite state space. The notion of controllability of a predicate is defined, and the supervisory predicate control problem introduced is solved. A closed-form expression for the weakest controllable predicate is obtained. The problem of controlling discrete event systems under incomplete state observation is also considered and observability of predicates is defined. Techniques for finding the extremal solution of Boolean equations are used to derive minimally restrictive supervisors