Decentralized control of discrete event systems using prioritized composition with exclusion

This paper studies the decentralized control problem of discrete event systems via prioritized composition with exclusion (PCX). PCX was obtained by extending prioritized synchronous composition (PSC) in order to model various Boolean modes of decision fusion resulting from the exclusivity of participation in system interactions Chandra, V et al. (2003). PCX decision fusion allows additional modes of decision fusion beyond the AND/OR architecture considered in Yoo, TS et al., 2002. We present a definition of PCX co-observability, which together with controllability and L/sub m/(G)-closure serves as a necessary and sufficient condition for the existence of decentralized supervisors under PCX decision fusion. We also provide an algorithm for testing the PCX co-observability which has the computational complexity that is quadratic in plant states and cubic in specification states. Next the properties of PCX fusion architecture are presented. Finally, the exclusive operation is extended from two supervisors to n supervisors, and corresponding decentralized control has been studied.