Study on job shop scheduling with sequence-dependent setup times using biological immune algorithm

Sequence-dependent setup times are one of the most important factors for the optimization of scheduling the production targets. Usually, they include the changing of tools, fixtures, cutting tools and the cleaning of production equipments. Some of them are relevant not only to the sequence requirement of the products to be processed on the equipment, but also to the processing requirement of the adjoining sequence. In this paper, a job shop scheduling problem with sequence-dependent setup times is described. A mixed integer program model is adopted to deal with this type of problem, and a scheduling algorithm based on biologic immunity mechanism is introduced. The result shows that the antibody encoding method and the mechanism of antibody proliferation and suppression can not only ensure the diversity of the antibody, but can also greatly improve the effectiveness of dealing with complex problems. Finally, a scheduling problem of finishing processing for a woollen mill is analyzed with its result described.