Research On Multi-objective Flexible Job Shop Scheduling Considering Poor Incoming Material Quality

The auto industry occupies a very important position in the development of the manufacturing industry.my country's auto industry is dominated by automakers.The development of auto parts,especially the automotive parts and components industry,is seriously lagging behind developed countries such as Japan,Germany and the United States.,Joint ventures or imports,unable to sustainably support the development of the entire vehicle industry.Auto parts have the characteristics of high added value,high complexity,and high differentiation,and are mostly processed in flexible workshops.The raw materials of auto parts companies often come from multiple countries,multiple suppliers and have many types.Under the influence of international relations,epidemics and other factors,it is easy to cause poor quality of incoming materials and material delays,which will adversely affect the production plan of the company.Impacts often exist and often lead to problems such as delays and line suspensions.However,in the research on dynamic scheduling of flexible job shop,there is no related research that considers the disturbance of incoming material quality.The main research content of this paper is as follows: Firstly,through the combination of theoretical research and practical investigation,the literature research method is used to summarize the dynamic targets,multi-target selection,algorithm selection and other aspects of dynamic scheduling of multi-object flexible job shop.In this paper,poor material quality is regarded as a disturbance event,and the minimum and maximum completion events and the minimum machine load are the targets.The improved NSGA-? algorithm is selected to solve the related problems.Next,this article analyzes the occurrence of poor quality of incoming materials and its impact on the initial scheduling plan of the flexible job shop.According to the type and time of occurrence of poor quality of incoming materials,whether the process delay caused by poor quality of materials affects subsequent processes Classification standards,using the idea of man-machine coordination to propose corresponding rescheduling strategies.In order to better illustrate the effectiveness of the rescheduling strategy proposed in this article and the improved algorithm,the rescheduling strategy proposed in this article is compared with the material delay rescheduling strategy in related literature.The disturbance impact rate R is reduced by 33.54%,indicating that the strategy in this article is better..Finally,an automobile engine electric control unit factory was selected as an example,and the material delay rescheduling strategy proposed in this paper was used for rescheduling research.The disturbance influence rate was reduced by nearly 60%,indicating that this strategy can greatly reduce the impact of poor quality of incoming materials on production scheduling.influences.In terms of demonstrating the effectiveness of the algorithm,the NSGA-? coding and crossover operator are improved according to the existing research in the example solution and compared with the basic NSGA-? algorithm results.The improved NSGA-? algorithm results are greatly optimized.