Control of Partially-Observed Discrete-Event Systems:

The State of the Art and Some New Results


Professor Stéphane Lafortune


Department of Electrical Engineering

and Computer Science


University of Michigan



We present an overview of key results on the control of partially-observed discrete-event systems.  Both centralized and decentralized control architectures are considered.  The control framework adopted is that of the theory of supervisory control of discrete event systems, initiated by Ramadge & Wonham in the 1980's.  Four key properties of this discrete-event system theory are:  controllability, nonconflicting, observability, and co-observability.  We focus on the properties of observability and co-observability.  We present a novel decentralized control architecture where the control actions of the individual supervisors are combined by “fusion by union'' (of enabled events)  for certain controllable events and “fusion by intersection'' for the other controllable events.  The properties of this architecture are described and contrasted to previous architectures considered in the discrete event systems literature.  Recent results on the complexity and decidability of the synthesis of safe and nonblocking partial-observation supervisors are presented.


Friday, February 1, 2002

3:30 - 5:00 p.m.

1500 EECS