Hybrid Robust Scheduling For Flow Shop Based On Fuzzy Theory

As the key technology of modern business management, production scheduling is getting more and more attention in recent years. People have been aware that it will increase the economic benefit of enterprises with high quality and high efficient scheduling, which it is a good way to strengthen the competitive of enterprises. The production scheduling of discrete manufacturing industry belongs to combined optimization problem based on mathematic. And most of the traditional scheduling problems are NP-Hard problems, which it means that it is very complex to solve any scheduling problem. Therefore, it combines the merits of theoretical significance and practical value to research production scheduling.Being a kind of production scheduling, flow shop scheduling problem (FSSP) is the simplified model ofpractical model and used widely. In the past40years, most of the researching about FSSP is centered on static environment, which means that there is no uncertain information and variation in the manufacturing process. However, static environment is rare in reality. There is so much uncertainty, such as the breakdown of machinery, changing ofprocessing time and so on. With the developing of scheduling researching, it becomes more and more complex to solve a scheduling problem. Contemporary, it has been a hot issue to research a robust scheduling as the uncertain information existing in scheduling in recent years. And the more solution is based on proactive scheduling or reactive scheduling, it is fewerto use mixed model.The paper is about researching the scheduling with the breakdown of machinery based on FSSP. It is decided that proactive scheduling and reactive scheduling will be used at the same time to deal with the uncertain information. And both of them will be based on fuzzy theory to ensure the scheduling better. The genetic algorithm (GA) is used to solve the scheduling. The main tasksofthe paper are as follows:(1)It is a FSSP with the breakdown of machinery, which using fuzzy theory to build the mathematical model. The object is to choice difference decision in connection with difference state of scheduling. The result is to get a initial robust scheduling using proactive scheduling, which makes sure that the initial robust scheduling has not bad performance on both stability and performance. The concrete way is to insert idle time in the scheduling. And the duration of the idle time is decided by fuzzy theory. Finally, it is solved by GA. It is improved that the initial robust scheduling is as predicting by program simulation, which it has not bad performance on both stability and performance.(2)It is a FSSP with bi-objective function solving, which is performance and stability, by building hybrid robust scheduling. The issue is that there are both machine breakdown that can be predicted (MBY) and machine breakdown which cannot be estimate (MBN). It depends on fuzzy theory to insert idle time to absorb MBY and designs a kind of fuzzy rule to deal with MBTM, which is to select a proper method of rescheduling. It is demonstrated that some of breakdown can be absorbed by proactive scheduling and it will be selected a better rescheduling to deal with others breakdown based on fuzzy rules in reactive scheduling.