Multi AGV Logistics Sorting System Planning And Scheduling Optimization For Dynamic Time Window

With the wide application of Internet information technology,the innovation of enterprise development strategy and the renewal of internal management mode,together with the strong support of the state,e-commerce enterprises have been developing in a blowout mode,accounting for a higher and higher proportion in the national economic development.Therefore,people from all walks of life gradually pay close attention to the development of various modules in the e-commerce industry.Customers placing orders on the e-commerce platform mainly focus on two points: the first point is the quality of the goods themselves,the second point is the efficiency of arrival,and the time when the goods reach the customers,that is,the shorter the time,the better.The first point is determined by the characteristics of the commodity itself,which requires the e-commerce platform to strictly manage each shop.The second point puts forward the importance of order processing efficiency to customer satisfaction.In the whole order processing process,sorting takes up 48% of the processing time,so the logistics sorting system planning and scheduling optimization can effectively shorten the processing time and improve the order processing efficiency.At present,both the Asian No.1 warehouse of JD's own logistics and the distribution centers undertaken by Ali,Suning and other e-commerce platforms are gradually developing towards the direction of "automation","intelligent informatization" and "unmanned".The customer order sorting mode has also changed from "people to goods" to the current "goods to people" mode,the most typical of which is AGV car logistics sorting Pattern.By analyzing the existing logistics sorting system of distribution center,we find that there are many problems,which are mainly summarized as follows: the first AGV car is unreasonable in number,resulting in the waste of fixed resources;the second AGV car runs too long in the sorting process,resulting in the sorting operation can not be completed on time;the third AGV car is prone to collision and otherconflicts in the running process.Therefore,in view of the above San problems,this paper will propose corresponding solutions.The first is to determine the number of AGV cars based on queuing theory.According to the queuing system and queuing theory of AGV trolley in a distribution center in Jingdong,the constraint condition is that when the sorting system reaches a stable state and the waiting time of customers' orders is less than the longest waiting time that customers can tolerate,the queuing model of AGV trolley logistics sorting system is established to determine the AGV needed in each time period Number of cars.The second is the research of multi AGV path planning based on time window.First,the electronic map is established according to the actual plan.First,the original Dijkstra algorithm is used to determine the travel path of a single AGV car,and then the original Dijkstra algorithm is combined with the time window to determine the shortest travel path of a multi AGV car.Third,AGV car conflict and coordination strategy.Firstly,the conflict types and driving rules of AGV car in the driving process are determined,and two types of conflict coordination strategies are proposed: the coordination strategy based on speed adjustment and the coordination strategy based on path change.Finally,the above two coordination strategies are verified by Flexsim simulation software.