Research On Warehouse Layout Strategy Of Parts-to-Picker Fulfillment System

In recent years,the e-commerce has developed rapidly and gained popularity in daily life,which promotes the consumption upgrading.The order fulfillment systems face increasingly severe challenges as the demands increase.This situation forces order fulfillment systems to work proficiently and accurately during order picking process.The parts-to-picker system is a new kind of technology which is widely used in e-commerce companies.In order to improve the efficiency of the system,this paper optimizes the picking stations location from a tactical design perspective.Besides,aisle configuration and storage policy are also taken into consideration to investigate the effects on expected travel distance.First,we propose a 0-1 programming model to decide the picking station location,then analyze the travel distance on different number of stations.Second,the influence of the storage strategy on the expected travel distance and system efficiency is discussed.Through a large number of numerical experiments and data analysis,we draw the following conclusions:(1)The increase in the number of picking stations will reduce the expected distance,with average 10% distance savings,we notice that the advantages tend to decrease with per additional station;In the traditional aisle configuration,the optimal arrangement rule is close to 2n-equal-point rule,the gap is within 2%,and as the height of the warehouse increases,the gap decreases gradually;while the solution of the common arrangement rules in practice is inferior to the 2n-equal-point rule.(2)The flying-V layout can save 8-18% distance comparing with traditional layout,and the distance saving is related to the number of the picking stations and warehouse size.When the warehouse is in reasonable size,saving 10% distance only need to sacrifice about 1% of the space.(3)In the traditional and flying-V layout,turnover-based storage policy can save more than 15% of the expected distance comparing with random policy.The optimal layout of picking stations under the random storage strategy is also suitable for the turnover based storage strategy.The increase in the number of classifications will reduce the expected distance,but the distance saving is not significant.The average expected distance can only be reduced by about 0.5% from two-class to three-class strategy.The lower bounds given by the full turnover-based storage strategy can only save 1% of the potential expected distance compared to two-class strategy.The increase in the number of classifications does not bring significant distance savings,thus two-class strategy is good enough to obtain satisfactory solutions.