| With the continuous expansion of the aviation market,a large number of private capital has entered the aviation manufacturing field,which has not only promoted the continuous development of the aviation industry,but also brought about fierce market competition.In the field of aviation parts trial-production,trial products have high technical requirements,strict quality control and variable demands.Emerging private enterprises generally have problems such as low production efficiency,high cost,long delivery cycle and low pass rate of the first delivery.The trial shop belongs to the flexible job shop,and the equipment,operator and processing order are highly flexible.The traditional empirical scheduling method is difficult to adapt to the requirements of flexible job production.It is of great significance to study the targeted workshop scheduling method to improve the production performance of such enterprises.In this study,the production and outsourcing processing status of an aircraft parts trial-production enterprise are investigated,and the characteristics of its flexible job shop are analyzed from the perspectives of multi-dimensional heterogeneity of equipment,operators and outsourcing scheduling process.Then the scheduling problems existing in such workshops are summarized,and the requirements for optimizing flexible job shop scheduling are put forward.Two kinds of optimal scheduling model are put forward.On the one hand,the flexible job-shop scheduling problem(FJSP)with extended dual resource constrained is raised based on considering the influence of equipment and operator heterogeneity on the workshop production performance,and its optimal scheduling model is established,which takes the total completion time and total completion cost,total tardiness,bottleneck equipment load and bottleneck operator load as the objective functions;On the other hand,the FJSP with extended dual resource constrained with outsourcing allowed is raised,based on the integrated optimized scheduling of internal and external processing resources,and its optimal scheduling model is established,which takes the total completion time and total completion cost,total tardiness,internal bottleneck equipment load,internal bottleneck operator load as the objective functions.The solving algorithm and multi-objective decision-making method are studied for models.Based on the framework of fast non-dominated sorting genetic algorithm with elite strategy(NSGA-II),three neighborhood search operators and an integrated fitness sorting algorithm are designed for the optimization goal of the scheduling model,which are used to improve the NSGA-II algorithm for solving scheduling model.At the same time,on the basis of considering the internal relationship of each objective function,the method of weighting based on grey relational degree is designed,and the weighted TOPSIS method is used to evaluate and select the Pareto solutions of the scheduling model.In the end,the two optimal scheduling models are applied to the flexible job shop scheduling of an aircraft parts trial-production enterprise.The two methods proposed in this paper can reduce the total completion time by 7.86% and 17.1%,the total completion cost by 6% and 5.8%,the total tardiness by 74.4% and 100%,the bottleneck equipment load by 21.8% and 28.4%,and the bottleneck operator load by 12.7% and 28.5%,respectively.All the objective functions are optimized obviously,which indicates that the models and method have good application effect.At the same time,the scheme based on the improved algorithm is obviously better than the scheme based on the NSGA-II algorithm.In addition,the comparison results of the two optimization schemes show that the optimal scheduling scheme based on FJSP model with extended dual resource constrained with outsourcing allowed can significantly optimize the other four objectives while a little increasing of the total completion cost,which proves the effectiveness of integrating external and internal processing resources for scheduling in practical application. |
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