A modified method for supervisor specification and synthesis of a class of discrete event systems

A model-refining method is proposed to alleviate the complexity regarding specification interpretation of DES control problems. The legal constraint language is defined in terms of illegal states and events in contrast with constructing the automaton of the specification language. This method could provide a more intuitive view of the DES control problem and would be suitable for practical implementation. One example, which was commonly used in the literature, is illustrated to show the efficiency of the proposed method. Furthermore, under this framework, it is shown that the supremal controllable sublanguage can take a simpler form by the concept of illegal state set. A state-based supervisor synthesis procedure is presented and a simple example is illustrated.