An expert-system approach to industrial job-shop scheduling

The first part of this paper is devoted to the presentation of a software system for jobshop scheduling of batches under due date constraints and time-table constraints on work-stations. It is based on a heuristic technique for sequencing the jobs. It is actually run in a real workshop. The second part of the parper deals with an expert system methodology currently under development for the same kind of problems. The idea is to be able to integrate two kinds of knowledge about the production process : theoretical knowledge (issued from scheduling theory) which achieves the management of time, and practical knowledge (provided by the shop-floor manager) about specific technological constraints which must be satisfied by the actual production process. These constraints are usually not taken into account at the theoretical level. The knowledge representation and processing techniques of Artificial Intelligence enable realistic schedules to be obtained by simultaneous use of both sources of information.