Simultaneous scheduling of machines and Agvs using evolutionary optimization algorithms

Abstract

High degree of flexibility and quick response times have become essential features of modern manufacturing systems where customers are demanding for a variety of products with reduced product life cycles. Flexible manufacturing system (FMS) is proved to be the right answer to meet these challenges of global competition. The performance of an FMS is highly dependent on the selection of the right scheduling policy for the control system. Traditionally scheduling problems consider machines as the only constraining resources but this is no longer correct as material handling equipment is becoming more and more valuable resource in an FMS. Hence its operations should be optimized and above all synchronized with machine operations. Scheduling of an FMS is a well known NP-hard problem which is very complex, due to additional considerations like material handling and alternative routing. Literature reveals that, in many of the cases scheduling of both the machines and material handling system was addressed independently. Hence in this work an attempt has been made to schedule both of them simultaneously. Evolutionary algorithms have proved themselves as a better alternative for many of the optimization problems like scheduling.