An FMS Control Structure: Data Modeling and Execution Components

Abstract

This paper describes the data modeling and execution components of a flexible manufacturing system (FMS) control model. The execution unit operates based on the organizational and operational information that describes an FMS. We have developed a unified machine model for the various kinds of machines and controllers. The layout and connection of them are represented in Port Connection Graph (PCG). The operational information is represented in the Process Flow Graph (PFG) and Task Flow List (TFL). For the execution unit, the thread concept of the concurrent system has been adopted in order to implement a manufacturing process where multiple parts can be manufactured simultaneously. Specially, the database unit is interfaced to the internet such that the manager or customers can access the database tables through a web browser. These control components work directly with a decision-making model described in the literature. Used together, the components can be combined into a fully functional FMS control system. An implementation in a full-scale FMS laboratory is described.