Job shop scheduling with dynamic fuzzy selection of dispatching rules

Abstract

Although the academic contribution to job shop scheduling is abundant, its impact on practice has been minimal and so the preferred approach to job shop scheduling in industry is the use of dispatching rules. A major criticism of dispatching rules is that there is no single universal rule, and the effectiveness of a dispatching rule depends on the scheduling criterion and the prevailing conditions in the job shop. In this paper, the authors propose a fuzzy scheduler that uses the prevailing conditions in the job shop to select dynamically the most appropriate dispatching rule from several candidate rules. This method is applied to a formal testbed job shop problem and a much larger problem that is representative of a real industrial problem. The results indicate that the fuzzy scheduler is effective.