Controller synthesis for parameterized discrete event systems

Les systèmes à événements discrets sont des systèmes dynamiques particuliers. Ils changent d’état de fa¸con discrète et le terme événement est utilisé afin de représenter l’occurrence de changements discontinus. Ces systèmes sont principalement construits par l’homme et on les retrouve surtout dans les secteurs manufacturier, de la circu- lation automobile, des bases de données et des protocoles de communication. Cette thèse s’intéresse au contrôle des systèmes paramétrés à événements discrets où les spécifications sont exprimées à l’aide de prédicats et satisfont une condition de similarité. Des conditions sont données afin de déduire des propriétés, en observation partielle ou totale, pour un système composé de n processus similaires à partir d’un système com- posé de n0 processus, avec n ≥ n0. De plus, il est montré comment inférer des politiques de contrôle en présence de relations d’interconnexion entre les processus. Cette étude est principalement motivée par la faiblesse des méthodes actuelles de synthèse pour le traitement des problèmes industriels de taille réelle.Discrete event systems are a special type of dynamic systems. The state of these systems changes only at discrete instants of time and the term event is used to represent the occurrence of discontinuous changes. These systems are mostly man-made and arise in the domains of manufacturing systems, traffic systems, database management systems and communication protocols. This thesis investigates the control of parameterized discrete event systems when specifications are given in terms of predicates and satisfy a similarity assumption. For systems consisting of similar processes under total or partial observation, conditions are given to deduce properties of a system of n processes from properties of a system of n0 processes, with n ≥ n0. Furthermore, it is shown how to infer a control policy for the former from the latter’s, while taking into account interconnections between processes. This study is motivated by a weakness in current synthesis methods that do not scale well to huge systems

An Efficient Algorithm for Controller Synthesis under Full Observation

This paper presents a simple and flexible on-line synthesis algorithm that derives the optimal controller for a given environment. It consists of finding the greatest possible number of admissible event sequences of a discrete-event system with respect to a requirements specification. It generates and explores the state space on-the-fly and uses a control-directed backtracking technique. Compared to a previous algorithm of Wonham and Ramadge, our algorithm does not require explicit storage of the entire work space and backtracks on paths of arbitrary length to prune the search space more efficiently. The paper also discusses an implementation of our algorithm and includes an evaluation of its performance on a variety of problems. 1 Introduction Control problems involve finding an efficient machine that senses and controls an environment through connections and guarantees satisfaction of requirements [9]. These machines have wide applications in areas ranging from robotics and manufact..