A Systematic Methodology for Actuator Augmentation in the Supervisory Control of Discrete Event Systems

Abstract

Supervisory control theory of discrete event systems in the Ramade-Wonham paradigm addresses the problem of restricting the system evolution so that it conforms to certain predefined behavior commonly referred to as specifications. This theory states that a sequence of events that cause the plant to violate the specifications is suitably pruned or eliminated. However, in doing so, event traces, partial prefixes of which that actually meet control specification are eliminated as well. This happens for instance whenever a chain of uncontrollable event extensions render the plant behavior trajectory irrevocably outside the outlined specifications. Such partial conformance can be ensured if the capability of the system is augmented by additional actuators so that in the augmented plant there is a greater degree of control over uncontrollable events. It does not follow trivially where such actuators are to be placed. We propose an algorithm that enables us to identify states of the automaton where the new actuators need to be inserted, thus enlarging the scope of its applicability to system identification purposes as well.

Keywords

• modeling
• Industrial control
• Discrete Event Systems
• Supervisory Control Theory
• Automata
• Actuator Augmentation