Job-shop based framework for simultaneous scheduling of machines and automated guided vehicles

This paper deals with the problem of simultaneous scheduling of machines and identical automated guided vehicles (AGVs) which are well known difficult to solve problems. The studied problem can be modelled as a job shop where the jobs have to be transported between machines by AGVs. This article introduces a framework based on a disjunctive graph to modelize the joint scheduling problem and on a memetic algorithm for machines and AGVs scheduling. The objective is to minimize the makespan. Computational results are presented for a benchmark literature instances. New upper bounds are found, showing the effectiveness of the presented approach. (C) 2010 Elsevier B.V. All rights reserved.