Supervisory Control of Discrete Event Systems under Partial Observations of Events and States

In this paper, we study supervisory control of discrete event systems under partial observations. Most of the research on supervisory control considers a supervisor which takes a control action according to only event sequences. This paper proposes a supervisor which selects a control pattern based upon partial observations of events and states. We first derive necessary and sufficient conditions under which there exists a supervisor for a given language, namely, a control specification. It is shown that our supervisor is more powerful than a supervisor which uses only event sequences. Next, we study the case that there does not exist a supervisor for a given language. We present a sublanguage of a given language for which a supervisor exists.