Research On Flexible Flow-shop Scheduling Problem Based On Genetic Algorithm

The competition of the global market is increasing, manufacturing industry as an important part of the national economy, has been gradually transforming from the traditional mode of production to advanced manufacturing mode. With the upgrading of the production mode, enterprises face a serious challenge: what should they do to develop a program in line with the actual production needs of the workshop scheduling program smartly, quickly and accurately. Production workshop scheduling problem is the main way for the enterprises to achieve a reasonable allocation of resources, save production costs and enhance customer satisfaction. Therefore, it is of great theoretical and practical meanings for us to carry out the research work of workshop scheduling combining with the contemporary production mode.In this paper, the research object is the cable production workshop, and doing some research work about the flexible flow-shop scheduling problem. The main contents and innovations are as follows:(1) Establishing a mathematical model for the flow-shop scheduling problem based on the characteristic of the cable production. This paper analyzes the characteristics of the basic technology of cable products and the scheduling problem of cable production workshop. Aiming at the flexibility of machine, the flexibility of the product demand and the diversity of the scheduling problem in the cable production workshop, this paper puts forward to the core work of research: designing a scheduling method for solving the cable production workshop, and the method is also used to solve the multiple types of flow-shop scheduling problems. For the flexible cable production workshop, this paper uses the mathematical constraint method to construct the scheduling model.(2) Studying on the single-objective scheduling method in flexible flow-shop based on genetic algorithm. Aiming to the essence of the flexible flow-shop scheduling:machine selection and workpiece sorting, this paper adopts the concept of the matrix coding, puts forward to a single point cross operation method based on matrix row/column and a random point mutation operation method of matrix elements based on probability selection.Then this paper designs an individual neighborhood selection method and the population evolution strategy which can effectively improve the population diversity and convergence. Finally, aiming at the minimization optimization problem, a simple criterion of fitness evaluation and a termination criterion of multi-parameter control are proposed.(3) Studying on multi-objective scheduling method for the flexible flow-shop based on Pareto sorting. Combining with the multi-objective scheduling problem of actual production workshop, and aiming at the characteristics of multi-objective optimization problem, according to the single-objective scheduling method, this paper put forward to a multi-objective scheduling method based on Pareto dominance relation and crowding distance ranking. This method proposes an elite individual retention strategy which includes three aspects: the combination of old and new groups,combining with roulette and championship selection ideas to retain outstanding individuals; retaining the population to make the sub-goals to achieve the optimal part of the individual; the use of independent external memory to save and update the Pareto optimal solution.(4) Combining with the actual needs of the cable production workshop and the two methods of scheduling proposed by pervious chapters, this paper design a set of scheduling system which can be applied to the cable production workshop. The system can achieve the production data query, update and develop scientific and rational scheduling programs for the production workshop.