The behavior mapping of systems has undergone rapid change with advances in technology. The representation has become digital with state description of the behavior. This manifestation is called Discrete Event Systems (DES), exhibiting properties such as non – determinism, conflict and parallelism[1]-[3]. Supervisory Control Theory (SCT)[8],[9] is chosen as a modeling paradigm and Programmable Logic Controllers (PLC) [10] – [12] as an implementation tool for DES. This work investigates the use of Fuzzy Petri nets in supervisory control and suggests a modified and improved version called Fuzzy Automation Petri net (FAPN) as a modeling tool. It presents a systematic approach to the synthesis of Fuzzy Petri net based supervisor for the forbidden state problem using supervisory design procedure. The controlled model of the system can be constructed from this FAPN net structure. The implementation is using Flexible Manufacturing System (FMS) as an example of DES. The results can be interpreted and applied to high level manufacturing systems, where the role of the supervisor is to coordinate the control of multiple machines or to low level manufacturing systems, where the control function is to switch ON/OFF with respect to the dynamics between different valves.

Keywords: FMS, Fuzzy Petri nets, PLCs,