2016 13th International Workshop On Discrete Event Systems Wodes

2016 13th International Workshop on Discrete Event Systems (WODES)

Supervisory Control of Discrete-Event Systems

This book shows how supervisory control theory (SCT) supports the formulation of various control problems of standard types, like the synthesis of controlled dynamic invariants by state feedback, and the resolution of such problems in terms of naturally definable control-theoretic concepts and properties, like reachability, controllability and observability. It exploits a simple, abstract model of controlled discrete-event systems (DES) that has proved to be tractable, appealing to control specialists, and expressive of a range of control-theoretic ideas. It allows readers to choose between automaton-based and dually language-based forms of SCT, depending on whether their preference is for an internal-structural or external-behavioral description of the problem. The monograph begins with two chapters on algebraic and linguistic preliminaries and the fundamental concepts and results of SCT are introduced. To handle complexity caused by system scale, architectural approaches—the horizontal modularity of decentralized and distributed supervision and the vertical modularity of hierarchical supervision—are introduced. Supervisory control under partial observation and state-based supervisory control are also addressed; in the latter, a vector DES model that exploits internal regularity of algebraic structure is proposed. Finally SCT is generalized to deal with timed DES by incorporating temporal features in addition to logical ones. Researchers and graduate students working with the control of discrete-event systems or who are interested in the development of supervisory control methods will find this book an invaluable aid in their studies. The text will also be of assistance to researchers in manufacturing, logistics, communications and transportation, areas which provide plentiful examples of the class of systems being discussed.

Autonomous and cooperative control of networked discrete-event systems

This thesis considers networked discrete-event systems. The overall system is a network of subsystems, each of which includes a technical process modelled by an I/O automaton together with a controller and a network unit. These subsystems are interconnected by physical couplings and digital communication links. An important characteristic of the networked discreteevent systems is the partial autonomy of the subsystems, which is reflected by the fact that each subsystem solves its local tasks individually. Cooperation among the subsystems becomes necessary if physical couplings or control specifications have to be resolved by two or more subsystems in order to satisfy the local tasks. Hence, the subsystems participate in satisfying cooperative tasks by adapting their behaviours while using the communication network without a coordinator. In these situations the following question arises: When and what information has to be exchanged by the subsystems and what should the structure of the communication network look like? As a main result of this thesis, it is proved that the subsystems in the networked discrete-event system determine deadlock-free execution orders of cooperative tasks with distributed model information by using the communication network and solving their local tasks. The applicability of the cooperative control solution is demonstrated by means of a collaborative process at the Handling System HANS. Markus Zgorzelski received his Bachelor in Electrical Engineering and Information Science from the Ruhr-Universität Bochum in 2011 and he received his Masters in Electrical Engineering and Information Science from the Ruhr-Universität Bochum in 2014. From 2014 to 2020 he was a scientific co-worker at the Institute of Automation and Computer Control, where he obtained his PhD. His research was focused on networked discrete-event systems.