A Method For Online Order Insertion Release In Robotic Mobile Fulfillment System

B2C e-commerce is developing rapidly.Its advantages of convenience and fast logistics not only bring consumers high-quality shopping experience,but also bring challenges to warehouse order processing.Order picking is the most important operation process in warehouse.Its operation cost accounts for about 60% of the total operation cost of warehouse.Due to the high labor cost and low order picking efficiency of the traditional "picker-to-parts" order picking system,B2 C e-commerce platforms,such as JD and Amazon,have begun to use the "parts-to-picker" robotic mobile fulfillment system for order picking,which has low labor cost and high order picking efficiency.Order release is the primary link of online order processing in robotic mobile fulfillment system and directly affects the overall performance of the system.In practice,the online orders are released in batches and the orders need to wait in batches,and the order box in which an order is placed will be idle and wasteful after the picking is completed,which leads to the reduction of efficiency and waste of resources.This study puts forward an online order insertion release method in robotic mobile fulfillment system.This method can effectively reduce the waiting time of orders in the order pool.After a new order is inserted,the racks that need to be transported to complete the order can be fully utilized,which can effectively improve the order picking efficiency.However,this method also brings two new decision-making problems: the problem of order selection during order insertion and the problem of task reassignment of moving racks for AGV after order insertion.In order to solve the above problems,this thesis conducts research on the online order insertion release method of robotic mobile fulfillment system.The main research work is as follows:(1)Decision analysis of insertion release of online orders in robotic mobile fulfillment system.Firstly,the order picking process of robotic mobile fulfillment system is analyzed.Secondly,the key influencing factors and complexity of two decision problems brought by online order insertion release in robotic mobile fulfillment system are analyzed.(2)Research on order selection method of online order insertion release in robotic mobile fulfillment system.Firstly,the order selection problem of online order insertion release in robotic mobile fulfillment system is described.Then,the calculation method of the rack quantity required for the order waiting to be picked and those unpicked goods in picking station is proposed.Finally,the order selection algorithm based on the minimum rack quantity is introduced in detail and the complexity of the algorithm is analyzed.(3)Research on task reassignment method of AGV under online order insertion release in robotic mobile fulfillment system.Firstly,the problem of the rack moving task reassignment for AGV under online order insertion release in robotic mobile fulfillment system is described.Then the workload of AGV is defined.Finally,the algorithm process of task reassignment for AGV based on workload balance is designed and the complexity of the algorithm is analyzed.(4)Numerical experiment and result analysis.According to the existing research,the relevant parameters of the robotic mobile fulfillment system and online order arrival are designed to generate the calculation examples.Then,the timeliness of algorithms is analyzed.Finally,the effectiveness of the online order insertion release method in the robotic mobile fulfillment system proposed in this thesis is verified through comparative experiments.This thesis provides a new method and a new tool for online order processing in robotic mobile fulfillment system in B2 C e-commerce warehouse,which is beneficial to enrich the theory of online order processing in robotic mobile fulfillment system.In practice,the theoretical results of this thesis can be used to guide the online order release decisions of B2 C e-commerce warehouse with robotic mobile fulfillment system,which is beneficial to improving the order picking efficiency.