| The vigorous development of e-commerce has contributed to the rapid growth of express logistics business volume.The express delivery business volume has exceeded 100 billion pieces in 2021.Express delivery services have deeply affected people’s lives.At the same time,a large number of express distribution market demand has led to the extensive development of enterprises.The poor service quality needs to be improved,which is difficult to meet the people’s personalized needs.With the maturity of related technologies and the promotion of policies,scholars and enterprises have begun to explore the use of unmanned vehicles in logistics and transportation.This paper sorts out the relevant theoretical research and achievements of unmanned distribution service,distribution facility location and bilevel program through literature research.Taking unmanned terminal distribution as the research scenario,aiming at the problems existing in the current distribution process,the concept of "drop-and-trail unmanned vehicle" is creatively proposed to optimize its service process.Taking this as the research object,the problem of facility location selection of unmanned terminal distribution station is discussed.The specific research contents are as follows:(1)Considering the bottleneck problem in the actual distribution service to optimize the unmanned terminal distribution service process.Through data inquiry and field research,the PERT/CPM network planning method is used to sort out the current routine unmanned vehicle delivery service.process.In view of its "insufficient delivery capacity","low punctuality rate" and "short pickup time",based on the the drop-and-trail unmanned distribution vehicle optimizes its terminal distribution service process through ECRS analysis method,shortens the critical path,and optimizes the service experience.(2)Considering the user satisfaction of unmanned distribution in practical application,establish the bilevel programming model for the location of unmanned terminal distribution station.The upper level planning takes the enterprise as the decision maker.The goal is to minimize the total delivery cost.In the case of considering the construction,operation cost and transportation and distribution cost of the distribution site,the initial feasible solution of the distribution site is determined;the lowerlevel planning takes the user as the decision maker.The goal is to maximize the terminal distribution service capacity.The demand coverage distance constraint reflects the user’s selection and distribution service capabilities,and determines the distribution scheme of demand points between different distribution sites.(3)Considering the complexity of the model,a two-stage hybrid algorithm is used to solve it.and analyze specific cases.First,the set of candidate delivery sites is obtained by clustering algorithm.On this basis,the bi-level programming model is solved by genetic algorithm.The upper model solves the location selection scheme by minimizing the cost,and the lower model optimizes the demand allocation scheme by maximizing the demand service capacity.The upper and lower layers are iteratively optimized,and finally the location selection plan and demand allocation plan of the distribution site are determined.And through case analysis,the influence of the number of distribution sites and the demand coverage distance on the distribution capacity is studied.Provide a reference for the location selection of unmanned terminal delivery. |
