Supervisory control of time-interval discrete event systems

• Main Authors: Brandin, Bertil, Su, Rong, Lin, Liyong
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2021
• Subjects: Engineering::Electrical and electronic engineering; Interval Automata; Event Forcing; Timed Controllability
• Online Access: https://hdl.handle.net/10356/152247
• Institution: Nanyang Technological University

Since the timed supervisory control framework was proposed, it has been adopted in many subsequent developments in various areas. Yet, the mechanism of explicitly enumerating time in terms of sequences of ticks significantly increases the number of states, causing major computational challenges in supervisor synthesis. To overcome this challenge, in this work we develop a theory of supervisory control of time-interval discrete event systems, whereby intervals are used to compactly encode sequences of ticks. By introducing the concepts of free and coercive (interval) languages, we are able to describe the impact of event forcing (i.e., time preemption) in a resulting time-interval language, upon which we introduce controllability property. It turns out that coercive languages are not closed under union, in contrast to free languages. The supremal controllable coercive language for a given time-interval plant and time-interval requirement exists, which can be computed by a synthesis algorithm presented in this paper.