Supervisory Control Of Discrete Event Systems Under Nondeterministic Observations
Lei Zhou, Shaolong Shu, Feng Lin · 2019
In the conventional supervisory control framework of discrete event systems with partial event observation, the observations of events are deterministic, that is, an event is either observable or not. However, in practical systems, due to reasons such as sensor limitations, sensor faults and packet losses in networks, the observations of events become nondeterministic. Hence it is necessary to re-consider the supervisory control problem. In this paper, we investigate the nondeterministic control problem which is to find a supervisor to ensure that the controlled system is safe. That is, the upper-bound language of the controlled system equals a given specification language. The key condition for the existence of such a supervisor is O-observability, which we define. To check O-observability, we construct an augmented automaton which includes all the information of the given discrete event system and its state estimates. Based on the augmented automaton, we find a method to check O-observability. We also synthesize a state-estimate-based supervisor to control the given system to achieve the given goal when the nondeterministic control problem is solvable.