Supervisory control of multiworkcell manufacturing systems with shared resources

Flexible-manufacturing systems (FMSs) may comprise a number of workcells where production resources are shared among the workcells for a variety of practical reasons. Although the utilization of independent workcells with sharing resources improves the flexibility of FMSs, avoiding deadlocks is essential for their successful implementation. This paper introduces a novel methodology for the synthesis of a set of conflict- and deadlock-free supervisors to individually control every workcell within a FMS inter-related by common (shared) resources. The proposed methodology is based on Extended Moore Automata (EMA) and Controlled-Automata theories. A new algorithmic procedure to analyze the concurrent operation of supervisors is also introduced in order to check for the existence or absence of deadlock states.