Nonblocking Hierarchical Control of Decentralized Discrete Event Systems

This contribution investigates the hierarchical control of decentralized discrete event systems (DES) that are synchronized by shared events. A hierarchical control architecture providing hierarchical consistency is introduced. Moreover, it allows for composition of decentralized subsystems on the high-level of the hierarchy and hence reduces the computational complexity of supervisory control synthesis for language inclusion specifications. In this context, a crucial issue is the nonblocking operation of the overall system. Our main theorem identifies sufficient conditions for this desirable property.