Using fujaba for the development of production control systems

Abstract

Current production control systems for e.g. a factory for cars or any other complex industrial good face two major problems. First, production control systems need to become (more) dezentralized to increase their availability. It is no longer acceptable, that a failure of a single central production control computer or program causes hours of down-time for the whole production line. Second, todays market forces demand smaller lot sizes and a more flexible mixture of different products manufactured in parallel on one production line. Common specification languages for embedded systems, like SDL, statecharts, etc. focus on the specification of (re)active components of production control systems like control units, actors (e.g. motors, valves), and sensors (e.g. switches, lightborders, pressure, and temperature sensors), and on the interaction of such reactive components via events and signals. They provide no appropriate means for the specification of (more) intelligent, autonomous production agents. Such autonomous production agents need knowledge of manufacturing plans for different goods and of their surrounding world, e.g. the layout of the factory or the availability of manufacturing cells. In addition, such production agents have to coordinate their access to assembly lines with other competing agents. This paper proposes to use (object-oriented) graph structures for the representation of production agents and graph (object structure) rewrite rules for the specification of their behaviour. We show how the FUJABA environment may be used to specify production agents and generate their implementation and to validate them via a graphical simulation.