Research On Virtual Re-sequencing Problem In Workshops Of Automobile Mixed-model Assembly Line

The automobile industry is the pillar industry of our country,which occupies an important position in the national economy.At present,due to the changes of economic environment at home and abroad,the automobile industry is facing fierce competition and severe market environment,so reducing costs and improving efficiency have become important issues for the development of enterprises.In recent years,the production mode of automobile industry has gradually changed from large-scale to multi-variety and small batch,and mixed-model assembly line is widely used in automobile industry.In the mixed-model assembly line,there are many kinds of products.Unreasonable production sequence will increase production cost and reduce production efficiency.Therefore,enterprises need more accurate production planning and scheduling.Re-sequencing is at the workshop level,considering the production demand of each workshop to re-sequence the sequence,which can reduce the production cost effectively,and is of great significance for enterprises to reduce costs.Virtual re-sequencing is an important aspect of re-sequencing research.In this paper,we discuss the problem of virtual re-sequencing in automobile mixed-model assembly line.In the actual production process,the painting workshop is adjacent to the assembly workshop on the mixed-model assembly line,and there are different production requirements in each workshop.But the production craft of each workshop has certain continuity,and only considering the re-sequencing of one workshop often can't meet the demand.In this paper,based on the virtual re-sequencing of a single workshop,we study the painting workshop and the assembly workshop as a whole.And according to the production requirement of the two workshops simultaneously,we built a virtual re-sequencing model,and then,transformed it into a linear 0-1 integer programming which is easy to obtain the accurate solution.First of all,we analyzed the production process of automobile mixed-model assembly line and the operation characteristics of each workshop.According to the research emphasis,we selected the painting workshop and the assembly workshop as the research objects of resequencing,and defined the limits of the research problems in this paper.Combined with the characteristics of virtual re-sequencing,we analyzed the problem of virtual re-sequencing of painting workshop and assembly workshop in detail,and clarified the research content.Secondly,we assumed and refined the re-sequencing problem of the two workshops,and clarified the objective function and constraints of the problem.And starting from the painting workshop,we gradually established the overall model of the two workshops' re-sequencing problem.Thirdly,we transformed the established model into a linear 0-1 integer programming model by taking the square and introducing new variables.And the correctness of the model was verified by an example.Finally,by comparing cost of the overall virtual re-sequencing and the separate virtual re-sequencing of two workshops,it is proved that the overall virtual resequencing model is effective to reduce the production cost.At the same time,when the other parameters are the same,increasing the sequence length-9)properly within a certain range can improve the total efficiency of virtual re-sequencing;and virtual re-sequencing has a better effect on the production line with the larger maximum painting quantity-8)and the key component with larger ratio of sequencing rules.This study provides a new research direction for solving the problem of re-sequencing in the automobile mixed assembly line.The linear 0-1 integer programming model established after the transformation can be solved directly by the existing commercial software,without the need to design a specific algorithm,which provides a reference for the virtual re-sequencing problem in other occasions.