Decentralized Control, Based On The Reliable Communication Delays, Discrete Event Systems And Fuzzy Discrete Event System

Discrete event system (DES) is a dynamic system with discrete states that are event-driven. In the most study of supervisory control theory about discrete event at present, the theory initiated by Ramadge and Wanham provides a systematic ap-proach for controlling discrete event system where a control specification is given by a language defined over the event set, and it is the most common research which is based on the logical level. On these bases, the theory of reliable decentralized super-visory of DES, initiated by Takai and Ushio, have been intensively investigated over the last decades. However, these results on reliable supervisory control are absence of communication delays, i.e., they are based on the assumption that the DES can not perform any action until the message of previous occurrence is processed and a proper control decision in made. Therefore, the communication delays for DES get more and more scholar's attention. In addition, to capture uncertainty appearing in states and state transitions of DES, Lin and Ying introduced fuzzy set theory into DES and thus extended theory of supervisory control of crisp DES to fuzzy DES by proposing fuzzy automaton model. Wang, Feng and Jiang make further research on the reliability of decentralized supervisory of fuzzy DES.In this paper, we revise some theory of reliability of decentralized supervisory of crisp DES, and extend it to fuzzy DES.In the first chapter, some preliminaries about supervisory control, observability and decentralized control of DESs and fuzzy DESs are introduced.In the second chapter, we mainly revise some problem about reliable decentral-ized supervisory control of DES with communication delays written by Liu and Lin. And we give the result about reliability of DES with communication delays based on the condition that every uncontrollable event is unobservable.In chapter three, we extend the theory of reliability of DES to fuzzy DES. Firstly, we introduce a fuzzy decentralized supervisor under communication delays. And give some properties about this fuzzy decentralized supervisor to deduce the main results. Secondly, we synthesize a k-reliable decentralized supervisor for fuzzy DES. And we generalized the definition of Euc-controllable and k-reliability delay-Ec-coobservable, proposing the concept of fuzzy DES. On the basis of these notions, we obtain such a result:given a nonempty fuzzy languageκ(?)(?)(G), a k-reliable fuzzy decentralized supervisor under communication delays exists, if and only ifκis (?)uc-controllable and k-reliable delay-(?)-coobservable. Finally, an illustrative example is provided.