Research On Dynamic Allocation Of Combined Body Storage Capacity Considering Body Resequencing Operation

With the increasing demand for “customization” of automobiles,international multinational auto companies have adopted flexible production lines and just-in-time production methods that can adapt to multiple models.Among them,the combined body storage not only undertakes the traditional buffer function,but also undertakes important resequencing function.Due to this complexity,the utilization of the combined body storage brings new problems to the smooth production of each workshop.Therefore,the dynamic allocation of combined body storage capacity is an important production management problem,and its rational allocation is of great significance for continuous production.This thesis takes the combined body storage in automobile manufacturing as the research object,considers the detailed process and characteristics of the production operation,and focuses on the dynamic allocation of the capacity of combined body storage.Firstly,it analyzes the working process of the combined body storage and the exit-entry relationship of bodies between the body shop,the painting shop,the assembly shop and the combined body storage.Then,the influencing factors of the problem are analyzed,including resequencing strategy,batch size,working time and takt time,and the stocks in the combined body storage is divided into unpainted body buffer,unpainted body resequencing buffer,painted body buffer and painted body resequencing buffer.It also analyzes the reasons for the four types of stocks.Next,considering the production characteristics,takt time and working hours of the three workshops,the change process of buffer is obtained by simulating the data.Based on this,aiming at the difference of body sequence between three workshops when entering and exiting the combined body storage,considering resequencing operation,a two-stage integer programming model with the objective of minimizing production waiting is established to determine the change process of resequencing buffer on the basis of buffer allocation problem.After that,based on the mathematical model,a genetic algorithm with modified operation is designed.According to the sequence difference between the output of the body shop and the requirement of the painting shop,as well as between the output of the painting shop and the demand of the assembly shop,the selection decision of resequencing is made in two stages,and the optimal result is obtained.Finally,the validity of the model and algorithm is verified by an example.The results show that the model can give the resequencing strategy with the smallest total production waits while satisfying the conditions of the storage capacity and the waits limit within a batch.At the same time,the dynamic allocation of combined body storage capacity in four types of bodies is given.Through the comparative experimental analysis of the waits limit within a batch and working time,it is verified again that the model and algorithm can better solve the practical problems in the capacity allocation of the combined body storage of the automobile factory.The capacity allocation research of the combined body storage focuses on the specific production operation of the workshop,that is,the problem of the body sequence mismatch,and combines the basic buffer function and the resequencing function of the storage between the workshops to establish a prioritized dynamic capacity allocation model within a cycle.This provides a new idea for the study of the buffer allocation problem in the combined body storage.