A mixed integer programming model for the cyclic job-shop problem with transportation

Abstract

This paper focuses on the study of cyclic job-shop problems with transportation and blocking. Within this domain, there are many real world problems like large scale productions, robotic cells, software pipelining or hoist scheduling. The aim in general is to find, for each machine, a feasible order of all the operations processed on this machine, so that an objective function is optimised. In this paper, we consider the problem of minimising the cycle time (maximising the throughput) in a job-shop environment, where the jobs are transported by a single robot between the machines. Additionally to the problem description, we will give some explanations and interpretation possibilities of the problem height, which is often omitted in the literature. As the main contribution, we will present a new integer programming formulation and show that it outperforms an existing model from the literature. (C) 2012 Elsevier B.V. All rights reserved.