Fabricare Project

Abstract

Society has experienced evolving mutations since the dawn of ages, specially on the last half of the twentieth century. The birth of an information society with a relevant number of jobs in the services sector has changed the status quo, and demanded enormous changes to the manufacturing enterprises' organisation.

From a technological point of view, it was observed that Computer Integrated Manufacturing (CIM) poses several drawbacks, namely excessive rigidity and centralization, so new approaches have been proposed in order to solve those problems, providing systems that are more adequate to today's and future social-economic context. Essentially, those new approaches advocate a set of attributes such as distribution, decentralisation, autonomy and agility. Moreover, the ability to represent the incompleteness of real world's knowledge in artificial worlds has also been identified as an essential attribute. To this point, Holonic Manufacturing Systems and Multi-Agent System seem as a promising approach.

In order to overcome these challenges, a solution based on Holonic Manufacturing Systems has been proposed using Multi-Agent Systems and Extended Logic Programming. In this solution the main entities in the manufacturing process are modelled as holons, each one contributing with a small parcel of the overall system's functionality. To demonstrate the previous concepts a prototype system has been developed, named Fabricare. The Fabricare system is composed of several holons which cooperate among themselves using an extension to the Contract Net Protocol. The goal of this cooperation is the dynamic scheduling of manufacturing orders. The system is compared from a structural point of view with previous research works.

The main contributions of this work are (i) the definition of a holonic architecture for manufacturing enterprises; (ii) the representation and identification of scenarios with incomplete information in manufacturing; (iii) an extension to the contract net protocol; (iv) a distributed scheduling algorithm; and (v) a prototype system.

Keywords: Multi-Agent Systems; Holonic Systems; Manufacturing; Intelligent Manufacturing Systems; Dynamic Scheduling; Extended Logic Programming; Incomplete Information.