A Hierarchical Architecture for Nonblocking Control of Discrete Event Systems

This contribution investigates the hierarchical control of decentralized DES which are synchronized by shared events. A multi-level 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. In our main theorem, marked state acceptance and marked state controllability are identified as sufficient conditions for this desirable property