Integrated Optimization Of Order Picking And Electric Vehicle Distribution Based On Estimation Of Distribution Algorithm

As an important part of the logistics system,the efficiency of order picking and distribution in distribution centers directly affects that of the distribution center and then affects that of the logistics system.In large distribution centers,there are hundreds of orders need to be processed every day and the quantity and category of goods in different orders may vary greatly.How to arrange an appropriate scheme of order batching and distribution to pick out customer orders and distribute them to customers with the lowest cost is an important problem to be solved urgently in distribution centers.In practice,picking work is completed by the personnel in charge of picking who will pick out goods from the corresponding storage location or the shelf and send these goods to the shipping area according to customer orders.Distribution work is completed by the personnel in charge of transportation who will distribute the selected goods to customers.The two tasks are closely linked,but they are generally two independent links and are completed by different departments in distribution centers.Therefore,many researchers take the order batching problem and the vehicle routing problem as two independent problems to solve.However,the result of order batching will directly limit the solution of the distribution problem,increasing distribution cost.Conversely,the distribution optimization scheme will also affect the optimization of the picking scheme.Due to the close relationship between picking and distribution,this paper integrates the two links and designs an integrated problem model and a solution method to help the distribution center reduce the costs of picking and distribution on the whole.At the same time,the application of new energy vehicles has become a trend.As more and more electric vehicles are put into the distribution business,this paper studies the electric vehicle routing problem in the distribution link instead of the traditional fuel vehicles.This paper mainly contains the following two contents:(1)Establish an integrated optimization model of order picking and distribution.Electric vehicles are introduced into the integration problem and the goal of the integration problem is to minimize the total cost(including the cost of picking and distribution time,the cost of using electric vehicles,and the cost of electric vehicles recharging time)of picking and distribution.Under the circumstance that the location distribution information of goods,S-shape routing strategy,the location information of recharging stations,the demands of customers and the parameter information of electric vehicles are given,an integrated optimization model of order batching and electric vehicle routing with pickup capacity constraint,electric vehicle time window constraint,capacity constraint,and power constraint is established.(2)Design an integrated model solution method based on Estimation of Distribution Algorithm(EDA).First,the EDA uses a well-designed decoding method to solve the order batching and distribution scheme corresponding to each individual.In the first step of the decoding method,an order sequence segmentation algorithm is designed to solve the order distribution scheme.In the second step,an improved seed algorithm is designed to solve the batching scheme of orders in each distribution path.Then,a probability model is used to record the statistics of the dominant population and guide the generation of new population.Finally,experiments are carried out to verify the effectiveness of the model and the algorithm.The results show that the EDA can effectively reduce the total cost of order picking and distribution,and solving the two links jointly is better than solving them in stages.