A Job-shop Scheduling Optimization And Simulation Study Based On Improved NSGA-? Algorithm

In the highly integrated global economy today,the competition among enterprises has shifted from domestic to international,from product quality,production efficiency,to comprehensive ability and the competition of product personalized services.In order to adapt to changes in the market,in addition to constantly developing new products to meet market needs,companies should adjust production scale and product varieties in accordance with market changes,that is,small batch,multi-category,and multi-batch switching production will become the mainstream of manufacturing mode.How to tap internal potential and improve the efficiency of production scheduling is a very important task.In the actual production practice,there are many dynamic factors in the workshop,which makes the shop scheduling problem more complicated.So far,no universal scheduling strategy has been found.At present,academic circles have already had many theoretical studies on production scheduling technology.Many of them are quite valuable researches,but there are generally insufficient deficiencies and inapplicability.Therefore,this paper improves the NSGA-II algorithm and applies it to flow shop scheduling problem and job shop scheduling problem optimization research.Firstly,this paper briefly introduces the research status of the domestic and foreign shop scheduling problems,and expounds the basic principles of the NSGA-II algorithm and common concepts in multi-objective optimization.After analysis,it is found that the general NSGA-II algorithm has the characteristics of premature convergence and difficult convergence when solving the problem of workshop scheduling.A kind of NSGA-II algorithm with adaptive parameters is proposed for this type of problem.The parameter dynamic adaptive method is added in the algorithm.Compared with the general NSGA-II algorithm,the improved algorithm can guarantee the quality of the global search to a certain extent under the premise of guaranteeing the search speed,avoiding the algorithm getting into premature and improving the optimal solution rate.Then the improved NSGA-II algorithm is applied to the calculation of the shop floor scheduling model.For flow shop scheduling,mixed flow shop scheduling and job shop scheduling problems,the algorithm structure was adjusted to meet different optimization problems.And the instantiation of the classic scheduling test method,engine shop model and locomotive workshop model verifies the practicability and effectiveness of the improved algorithm.Finally,flow-shop scheduling,hybrid flow shop scheduling and job shop scheduling were verified on Flexsim simulation software.The software can observe and analyze the complete scheduling process in a dynamic way.The results further prove the feasibility of the improved algorithm in practical production scheduling applications.The improved NSGA-II algorithm proposed in this paper improves the poor convergence of the original algorithm for the shop scheduling problem.Its calculated solution can solve the required result of the shop scheduling problem in production.Using the improved NSGA-II algorithm for the optimization and simulation of the shop scheduling system has a good guiding role in solving practical production scheduling problems.