Real-time supervisory control of automated manufacturing systems.

摘要

Automated manufacturing systems are generally composed of a number of interconnected material processing stations, a material transport system, a communication system, and a comprehensive management system. Supervisory control design consists of the formulation and synthesis of supervisors which implement corresponding control laws specifying how the management system is to react to the manufacturing system behaviour in order to satisfy given production specifications within the standing control enforcement constraints. To this purpose, different techniques such as knowledge engineering, Petri nets, timed transition models and real time temporal logic, and controlled automata may be exploited.; The main objectives of this work are, on the one hand, the extension of the existing supervisory control design techniques, based on controlled-automata concepts, to allow the treatment of hard temporal behavioural specifications; and, on the other hand, the development of guidelines for the implementation of the corresponding supervisors, specifically in relation to issues such as the monitoring of the plant, control evaluation, and control enforcement.; The contribution of this work to the field of automation in general, consists in the development of a formal approach to the design of supervisory control systems for automated manufacturing applications, which in view of the complex nature of most modern manufacturing facilities and of the supervisory control 'state of the art' in the field, is very desirable.; After reviewing the automated manufacturing context, with respect to management and supervisory control, supervisory control design, and device integration, the controlled automata framework considered in this work is presented. It provides the theoretical basis for the design of supervisors. Centralized supervisory control, modular supervisory control, and modular supervisory control under partial observation schemes are proposed.; Consequently, detailed supervisory control design procedures, based on the latter results, are introduced.; An approach to the computer-based implementation of supervisory controls, developed within the present framework, is subsequently proposed. Correspondingly an experimental setup based on 'off the shelf' industrial hardware is described.; A manufacturing cell example is then treated. The aim of the latter example is the illustration of the applicability, strengths and drawbacks of the design techniques presented.; Finally, conclusions are provided. These discuss the contributions and limitations of this work and possible areas for further study.