Metric based nonblocking supervisory control of discrete event systems

This paper considers metric based nonblocking supervisory control of discrete event systems (DESs). We introduce the definition of metric indicating distace from one state to other state. The states are paritioned into nonblocked states and blocked states based on metric. Then, we suggest the control law for supervisor which blocks blocks the event sequences from nonblocked states to blocked states. Moreover, we prove that the supervisory controller following the control law is nonblocking when the conditions are satisfied. Through the simple memory example, we show that the trade-off between efficiency and robustness can be easily controlled.