Hierarchical and decentralized multitasking control of discrete event systems

In this paper, a hierarchical and decentralized approach for composite discrete-event systems (DES) that have to fulfill multiple tasks is elaborated. Colored marking generators that can distinguish classes of tasks are used as the system model, and a colored abstraction procedure as well as sufficient conditions for nonblocking and hierarchically consistent control are developed. It is shown that the computational complexity for supervisor computation is reduced. A flexible manufacturing system example demonstrates the efficiency of the approach.