Hierarchical supervisory control of fuzzy discrete event systems

Hierarchical structuring of supervisory control which represents the vertical modularity, has been discussed in discrete event systems (DES) to resolve the control complexity of large-scaled systems. Recently, fuzzy discrete event systems (FDES) has been introduced as an extension to the crisp DES in order to better represent the uncertainties and imprecisions of asynchronous event driven dynamical systems. In this paper, we investigate the hierarchical supervisory control problem of FDES with partial observation for modeling large-scale systems with associated uncertainties in their states and event transitions. Some important definitions are introduced and a hierarchical supervisory control theory for FDES is established.