Research On Production Scheduling Based On Equipment Aging Effect And Flexible Maintenance Strategy

The manufacturing industry,which is regarded as the pillar of our national economy,is facing fierce international competition because of the downturn in exports caused by the recovery of global economic.The academic and engineering experts are actively exploring and striving to deal with the problems for keeping China's manufacturing industry in an invincible position both in the domestic and international market competition.Production scheduling is one key factor that affects the performance of manufacturing system.Therefore,reasonable and effective scheduling plans and equipment maintenance management strategies are important to improve the production efficiency and equipment utilization efficiency,and maintain the competitiveness of enterprises.Hence,it is vital to get the scheduling solutions through the scheduling model design and establishment that can reflect practical manufacturing conditions.In order to study the more practical permutation flow shop scheduling problem,this thesis considers the machine-based aging effect and the load-based flexible maintenance strategy,and assumes that the actual processing time of the job depends on the machine state.The maintenance activities are considered in this study as rate-modifying activity which is part of machine condition restoration.According to the hypothesis,a new hybrid linear programming model(MILP)is proposed.The purpose of the study is to provide more diversified scheduling schemes to decision maker about the sequence of job and the decision of maintenance.Due to the complexity of the problem,a novel two-stage solving program is proposed.The first stage is composed of an improved block-based evolutionary algorithm(NEH-BBEDA),which solves the problem of job sequencing and also is the input of second stage.The second stage contains a sub-population genetic algorithm II(SPGA-11)to solve the maintenance decision problem.Finally,the random case is simulated to show the effectiveness of the model proposed in this study.The validity of the proposed two-stage coupling algorithm is also verified by the simulation results,which provides a solution for the flowshop scheduling considering the machine aging and flexible maintenance.