This paper presents a modular liveness-enforcing supervisory control design for scalable discrete event systems. A maximally permissive monitor-based supervisory control policy is suggested using divide and conquer paradigm. A vector-covering approach is used to minimize essential set of legal markings and first-met bad markings. Providing that modules of system interact by Enable operator, it will be proved that monitor-based supervisory control methods can be applied modularly. Then, Enable operator of Petri nets (PNs) can be used to synthesize subsystems. This algorithm is implemented by extending a graphical PN drawing and analysis tool with supervisory control analysis modules as Java codes. The experimental results show that this approach constitutes a primary step towards a hierarchical procedure that overcomes whole reachability graph computation, which is a bottleneck in deadlock preventing supervisory control policies.
An O(n2) Algorithm for Supervisor Reduction/Localization of Discrete-Event Systems