Reliable decentralized supervisory control of discrete eventsystems

摘要

We consider a discrete event system controlled by a decentralizednsupervisor consisting of n local supervisors, and formulate a newndecentralized supervisory control problem, called a reliablendecentralized supervisory control problem. A decentralized supervisor isnsaid to be k-reliable (1⩽k⩽n) if it exactly achieves anspecification language under possible failures of any ⩽n-k localnsupervisors. So, k denotes the minimal number of local supervisorsnrequired to achieve the specification. First, we present necessary andnsufficient conditions for the existence of a k-reliable decentralizednsupervisor. Next, we consider the case that a k-reliable decentralizednsupervisor for a given specification language does not exist. We takentwo approaches in this case. In the first approach, we present annalgorithm for computing a sublanguage of the specification thatnsatisfies the existence conditions of a k-reliable decentralizednsupervisor. In the second one, we use a coordinator to synthesize ank-reliable decentralized supervisor without altering the specification