Hierarchical Interface-based Supervisory Control: Bi-level Systems

SCG Technical Report No. 0103 by R.J. Leduc, W.M. Wonham, and M. Lawford, Nov 2001


In this report we present a hierarchical method that decomposes a system into a high level subsystem which communicates with n >= 1 parallel low level subsystems through separate interfaces, which restrict the interaction of the subsystems. We first define the setting for the serial case (n=1), and then generalise it for n >= 1. We present a definition for an interface, and define a set of interface consistency properties that can be used to verify if a discrete-event system (DES) is nonblocking and controllable. Each clause of the definition can be verified using a single subsystem; thus the complete system model never needs to be constructed, offering significant savings in computational effort. Additionally, the development of clean interfaces facilitates re-use of the component subsystems


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