30 years of the Ramadge-Wonham Theory of Supervisory Control: A Retrospective and Future Perspectives
Full-Day Workshop at the 56th IEEE Conference on Decision and Control (CDC), on Monday December 11, 2017
- Stéphane Lafortune (University of Michigan, USA)
- Karen Rudie (Queen's University, Canada)
- Stavros Tripakis (Aalto University, Finland)
List of Confirmed Speakers
- Peter Ramadge (Princeton University, USA)
- Calin Belta (Boston University, USA)
- Kai Cai (Osaka City University, Japan)
- José Cury (Federal University of Santa Catarina, Brazil)
- Martin Fabian (Chalmers University, Sweden)
- Alessandro Giua (University of Cagliari, Italy)
- Hervé Marchand (INRIA, France)
- Richard Murray (Caltech, USA)
- Necmiye Ozay (University of Michigan, USA)
- George Pappas (University of Pennsylvania, USA)
- Sanjit Seshia (University of California at Berkeley, USA)
Introduction and Motivation
2017 marks the 30-year anniversary of the publication of the two seminal papers of Ramadge and Wonham on supervisory control of discrete event systems, in the January and May issues of the SIAM Journal on Control and Optimization (SICOPT) in 1987:
- [RW1] P.J. Ramadge and W.M. Wonham, "Supervisory Control of a Class of Discrete Event Processes", SIAM J. Control Optim., 25(1), 206-230.
- [RW2] W.M. Wonham and P.J. Ramadge, "On the Supremal Controllable Sublanguage of a Given Language", SIAM J. Control Optim., 25(3), 637-659.
These two papers launched the area of supervisory control of discrete event systems within the control engineering community. Their general framework based on regular languages and their finite automata representations provided powerful foundations for the development of this supervisory control theory by a worldwide community of researchers in control engineering, including continued contributions by Ramadge and Wonham with their students and collaborators. Nowadays, supervisory control à la Ramadge-Wonham is a broad theory that covers partially-observed systems, a variety of control architectures that exploit horizontal and vertical modularity, and extensions to timed systems. Indeed, [RW1] has over 3,300 citations according to Google Scholar, with yearly citations in the range of 121-171 since 2003. Supervisory control à la Ramadge-Wonham remains an active area of research, and several real-world applications have recently been demonstrated in domains ranging from electric vehicles in theme parks to patient support systems in MRI scanners, among others.
More recently, the area of formal methods in control has gained prominence in the control community, primarily in the context of cyber-physical systems that are abstracted as discrete transition systems subject to specifications expressed in temporal logic. The terminology "formal methods" comes from the computer science literature and it encompasses a set of mathematically-formal techniques that have been developed for the verification of hardware and software systems, and more recently for the synthesis of systems or programs that interact with their environment, or reactive systems. Reactive synthesis, as this latter problem is called, is fundamentally a problem of feedback control.
The Ramadge-Wonham theory of supervisory control is itself a formal method in control, for the case of specifications that can be expressed as regular languages, the same modeling paradigm as the uncontrolled system. In that sense, it is complementary to works on reactive synthesis that handle certain classes of specifications expressed using various fragments of temporal logics.
The goal of the workshop is to offer a retrospective of the Ramadge-Wonham theory of supervisory control and to present some of its recent developments and applications. In addition, the workshop will attempt to connect the Ramadge-Wonham theory with the emerging area of formal methods in control and more generally with the work in reactive synthesis in computer science. To this end, the list of speakers comprises researchers associated primarily with the area of supervisory control of discrete event systems and researchers associated primarily with the area of formal methods in control.
This workshop is very timely given the emergence of autonomous systems, especially in the context of cyber-physical systems, where stringent requirements of correctness and safety are placed on the higher-level supervisory control layer. At the same time, it will give our community an opportunity to reflect on seminal papers published 30 years ago that defined a new sub-discipline in control science and engineering.
The speakers will give talks that will be accessible to a wide audience of CDC attendees. The objective will be to combine the retrospective theme with the future perspectives theme, in presentations that will have tutorial value. Given the emergence of cyber-physical systems as an important area of research and given that there are typically multiple CDC sessions on discrete event systems, formal methods in control, and hybrid systems, we expect that a large number of CDC attendees, in particular students, will be interested in this workshop.
- 8:30-8:45am: Participants arrive
- 8:45-9:00am: Opening remarks (organizers)
- 9:00-10:00am: Two presentations
- 10:00-10:30am: Morning coffee break
- 10:30-12:00pm: Three presentations
- 12:00-1:30pm: Lunch
- 1:30-3:00pm: Three presentations
- 3:00-3:15: Afternoon coffee break
- 3:15-4:45pm: Three presentations
- 4:45-5:00pm: Brief closing remarks (organizers)
We look forward to seeing you in Melbourne!