Design and implementation of decentralised supervisory control for manufacturing system automation

Abstract

Supervisory control theory, which was first proposed by Ramadge and Wonahm, is a well-suited control theory for the control of complex systems such as semiconductor manufacturing systems, automobile manufacturing systems, and chemical processes because these are better modelled by discrete event models than by differential or difference equation models at higher levels of abstraction. Moreover, decentralised supervisory control is an efficient method for large complex systems according to the divide-and-conquer principle. This article presents a solution and a design procedure of supervisory control problem for the case of decentralised control. We apply the proposed design procedure to an experimental miniature computer-integrated manufacturing (CIM) system. This article presents the design of fourteen modular supervisors and one high-level supervisor to control the experimental miniature CIM system. These supervisors are controllable, non-blocking, and non-conflicting. After the verification of the supervisors by simulation, the collision avoidance supervisors for automated guided vehicle system have been implemented to demonstrate their efficacy.