Modeling And Performance Analysis Of The Four-way Shuttle-based Storage And Retrieval System Based On Operation Strategy

With the rapid development of information technology and e-commerce,the logistics industry,as the third source of corporate profits,has gained unprecedented momentum for development.The warehousing system is the material and information transfer center of the enterprise logistics system,which has a decisive influence on the operation efficiency and cost of the entire supply chain.The four-way shuttle-based storage and retrieval system is an existing Intensive storage system with relatively advanced,high automation and high flexibility.Its appearance improves the performance of the storage system and avoids the large footprint,low operation efficiency and poor flexibility of traditional automated warehouse defects.For this reason,it has important theoretical and practical significance to establish a practical theoretical model for The four-way shuttle-based storage and retrieval system,and conduct research on operating strategies and system performance.At present,in the research of storage system by domestic and foreign scholars,the operation strategy of shuttle and lift is mostly a single serial strategy,but the parallel operation strategy exists in real scenarios and will provide a significant positive impact on system performance.Therefore,this article focuses on The four-way shuttle-based storage and retrieval system with parallel operation strategy,selects system performance indicators such as equipment utilization,system response time,and external queue waiting time,and establishes a separate-join queuing network model and a SOQN model,Design an algorithm based on the coxian distribution and MGM to solve it,so as to analyze the changes in system performance under different operating strategies.First,research the outbound process.Since the inbound and outbound process logic is similar,and the outbound efficiency determines the system service level,this article only considers the outbound process.The outbound process is divided into three parts:the horizontal operation of the shuttle,the vertical operation of the lift and the remaining operation of the lift.The parallel operation of lift and shuttle is innovatively added into The four-way shuttle-based storage and retrieval system,and the modeling content is separated into two strategies: parallel operation and serial operation.Secondly,the establishment of two operation strategy models.Considering that the service time of shuttle and lift obeys the general distribution and the queuing network formed by them belongs to the non-product solution,the coxian distribution is used to solve the above problem.In the modeling of the parallel operation strategy,the separation-confluence queuing network model is constructed,and the parallel part of the model is first decomposed by the closed queuing network,and the load-related throughput rate of the queuing network is calculated,which is regarded as the service rate of the first node in final open queuing network.This paper innovatively uses the Maximum Entropy Method(MEM)to solve the model;in the modeling of serial operation strategy,Matrix-geometric Method(MGM)is used to solve the model.Finally,analyze the model and system performance.Set the scale of the large-scale and small-scale system,use the Arena simulation software to calculate the simulation data,and compare with the theoretical model solved in this paper.The accuracy of the model in this paper is verified,and the model error is within 10%.Compared with the existing method,the error of the system performance index calculation can be reduced by 20%.On the basis of verification of reliability,18 system-scale The four-way shuttle-based storage and retrieval system were set up,and a single serial operation strategy was compared with a combination of serial and parallel strategies.Comparing with using the single serial operation strategy to build the model,adding the parallel strategy has better performance.The average system response time can be reduced by12.6%,the system response time at least can be reduced by 1.8%.The study found that the system can reach the optimal operating state under the condition of 80% of the shuttle utilization rate.Based on this,the optimal configuration of the shuttle for the system with different arrival rates is carried out,the conclusion of this paper is verified by an example analysis.