A General Architecture for Reliable Decentralized Supervisory Control of Discrete Event Systems

In this paper, we study the reliable decentralized supervisory control of discrete event systems (DESs) under the general architecture, in which the decision for controllable events employed is a combination of the conjunctive fusion and disjunctive fusion rules. For a plant equipped with n local supervisors, the notion of k-reliable (1 <= k <= n) decentralized supervisor is formalized and investigated here. By k-reliable decentralized supervisor, we mean that the specification can be achieved exactly even under possible failures of any no more than n - k local supervisors. It is worth noting that the standard decentralized supervisory control problem in the general architecture [14] can be regarded as a special case of k-reliable decentralized supervisory control with k = n. The main contributions of the paper lie on the proposed necessary and sufficient conditions for the existences of k-reliable decentralized supervisor and nonblocking k-reliable decentralized supervisor in the context of the general architecture, based on the notions of the (Sigma) over tilde (uc)-controllability and k-reliably (Sigma) over tilde (c)-coobservability of a sublanguage. This represents a generalization of the results in [11].