Optimization Method On Production Scheduling In Complicated Environment With Non-identical Machines

With the fast development of market economy and an increasingly competitive market,which requires companies to increase productivity,reduce production costs and enhance the competitiveness of enterprises.The core of planning production to reduce costs is to find a reasonable solution.Based on typical NP hard problem of manufacturing industry production process scheduling problem as the background,this thesis focus on processing differences in actual production equipments and rework and complex environments,and how to develop the optimal scheduling schema.Research on production scheduling problems in complex environment not only of theoretical significance and relevance.In this thesis,considering the characters of multiple machines and multiple stages of the production process under the hybrid flow shop processing environment to minimize the total production costs,we mainly focus on deterministic scheduling problem and rework scheduling problems.Thesis includes the following content:First,the literature review.By looking up the literature of the domestic and international scholars,hybrid flowshop scheduling problem and its modeling approach have been introduced,application and solving method is also reviewed;and also the non-identical parallel machine scheduling problem and rework are reviewed.Second,two models have been proposed for deterministic hybrid flow shop scheduling problem:the time unit model and serial model.For both the models,CPLEX solver has been used to get the exact scheduling solution,and the time domain T of time unit model has been analyzed.By experimental comparison,we analyse problem size which can be solved by CPLEX solver within the acceptable time.Third,we designed a kind of genetic algorithm for solving deterministic hybrid flow shop scheduling problems.As for different scale problems,parameters of genetic algorithm have been designed through simulation,and the last,result shows the stability and efficiency of genetic algorithm.Fourth,we consider the hybrid flow shop scheduling problem with rework and with the objective of minimizing the total production cost.CPLEX and genetic algorithms are used to solve the problem.