Research On Multiple Flexible Job Shop Scheduling Problem

Job-shop scheduling is a kind of typical production scheduling problem, which has received wide attention of scholars both at home and abroad. Along with the enhanced unpredictable market environment and the customers' demand for product diversity, the enterprises gradually adopted the production model of multi-varieties and small-batch, which makes there exists some flexibility in the actual production process, such as machine flexibility, operation sequence flexibility and so on. It has been proved that by considering the flexible factors in the manufacturing system, the enterprises not only can improve the production efficiency and reduce cost, but also can enhance their own competitiveness.This paper researches on the multiple flexible problem in the processing of jobs in Job-shop. Firstly, the description methods of multiple flexibility in Job-shop are summarized and analyzed, including machine alternative flexibility, routing alternative flexibility and operation sequencing flexibility. In view of the insufficiency of them, a new description method which is complete and doughtily application is proposed. Secondly, the mathematical model of the flexible Job-shop is built according to the actual production environment, and the scheduling target of minimize the maximum completion time is optimized. Thirdly, the ant colony algorithm is designed to solve the problem. Finally, through comparing with other's research results, the effectiveness and stability of the proposed algorithm are analyzed.The research results show that the optimization results of considering multiple flexibility is better than the results of not considering it; the optimization results of ant colony algorithm is superior to the IGA algorithm in literature for which also has good stability. The research results has certain guiding significance to the scheduling of multiple flexibility and the application of ant colony algorithm in Job-shop scheduling.