Compositional Synthesis of Maximally Permissive Supervisors using Supervision Equivalence Hugo Flordal * Department of Signals and Systems Chalmers University of Technology G¨oteborg,Sweden Robi Malik Department of Computer Science University of Waikato Hamilton, New Zealand Martin Fabian Department of Signals and Systems Chalmers University of Technology G¨oteborg,Sweden Knut ˚ Akesson Department of Signals and Systems Chalmers University of Technology G¨oteborg,Sweden November 1, 2007 Abstract This paper presents a general framework for efficient synthesis of supervi- sors for discrete event systems. The approach is based on compositional minimisation, using concepts of process equivalence. In this context, a large number of ways are suggested how a finite-state automaton can be simplified such that the results of supervisor synthesis are preserved. The proposed approach yields a compact representation of a least restrictive supervisor that ensures controllability and nonblocking. The method is demonstrated on a simple manufacturing example to significantly reduce the number of states constructed for supervisor synthesis. 1 Introduction This paper proposes a solution to the problem of supervisor synthesis in super- visory control theory of discrete-event systems (Ramadge and Wonham, 1989), * Corresponding author: flordal@chalmers.se 1