Modeling&Optimizing Of Retrieval Assignment Problem On Double-deep Multi-tier Shuttle Warehousing System

The traditional manual picking operation mode which rely on cheap labor has been unable to meet today's logistics picking operation requirements in e-commerce field.E-commerce enterprises need translate the low speed picking mode of operation which known as "people arrive" into the high speed picking operation mode which known as "goods arrive".Towards the "sorting based and storage supplement" operation character in flatbed e-commerce enterprises,the key issues in the development of e-commerce supplier warehousing logistics is how to achieve efficient and accurate order picking and quick response.This paper studied double-deep multi-tier shuttle warehousing system which applied to distributed automatic logistics system of e-commerce enterprises,and introduced its main hardware and operating mode.This paper studied the performance of the system and the operation strategies of the rearrangement assignment,the lift operation system can be divided into two types:single operation mode and double operation mode.In this paper,and analyze the system performance under the single operation mode of the lift and the operation strategies of the rearrangement assignment are taken as the research object.Based on the analysis and calculation of the working time of the shuttle and the lift,this paper studies the collaborative operation of the shuttle and the lift.This paper is the first study based on double-deep multi-tier shuttle warehousing system.This system has two storage location in depth and the rearrangement problems happens when the shuttle operates retrieval assignment.This paper using the improved genetic algorithm studies the rearrangement strategies problem,reduces the total time of the outbound task,and improves the efficiency of the shuttle system.The main contents and achievements of this paper are as follows:(1)Using the fill-grade factor to analyze the shuttle retrieval assignment characteristics.This paper is based on the fill-grade factor of double deep rack system,and it is studied that under the condition of random dispatching task,this paper puts forward two probabilities of storage location in the first and in the second lane of the double-deep multi-tier shuttle warehousing system and establishing the model of the cycle time of the shuttle carrier retrieval assignment under the fill-grade factor.(2)Based on the concept of fill-grade factor,the synergistic problem of shuttle and lift operation is studied.Through the study of the performance of the shuttle and the performance of the lift in the cycle,the equipment speed,equipment acceleration and fill-grade factor are studied quantitatively by modeling for the shuttle carrier cycle time and the lift cycle time.(3)Study on the problem of shuttle rearrangement assignment.In order to reduce the rearrangement distances and the number of rearrangements,this paper aims at minimizing the total task time of the shuttle,and used the improved genetic algorithm to solve the combinatorial optimization problem.In order to reduce the number of number of rearrangements,comparative study of three kinds of rearrangement strategies,with a view to reducing rearrangement distances,and comparative analysis the pros and cons of the three rearrangement strategies.