The Electric Vehicle Routing Problem With Time Windows

With the increasing challenges of the environment and energy situation,electric vehicles are getting more and more attention,and gradually replacing traditional internal combustion vehicles as an important distribution tool in the field of logistics distribution.EVRP is becoming a research hotspot in the field of combinatorial optimization.The large-scale application of electric vehicles in logistics distribution has extremely important practical significance,because electric vehicles have obvious advantages over traditional fuel vehicles.Firstly,zero emissions of harmful gases and carbon dioxide can be achieved,which can not only improve urban air quality,but also alleviate the global greenhouse effect to a certain extent.Secondly,the energy conversion rate of electric vehicle is higher than that of internal combustion vehicle,which can reduce the cost of distribution.This paper intends to study the EVRPTW with time windows.The research on EVRPTW can enrich the research contents in related fields and provide reference for the follow-up researchers to study related issues.Nowadays,electric vehicles are mainly divided into charging station type and battery swap station type.The construction cost of charging station is lower than that of battery swap station.However,due to the limitation of current electric vehicle accumulator and charging technology,the time cost of charging type is higher.With the breakthrough of technology,it is expected to realize low-cost and high-efficiency charging.So,in this paper,charging type EVRPTW was studied.EVRP is a variant of VRP.There are great differences between each other.In order to establish the mathematical model of EVRPTW,Firstly,this paper analyzed Capacitated Vehicle Routing Problem(CVRP)model,then further analyzed The Vehicle Routing Problem with Time Windows(VRPTW).Finally,according to the characteristics EVRPTW,the mathematical model is established.The model constraints include vehicle capacity limit,customer service time windows limit and electric vehicle mileage limit.In the course of driving,electric vehicles are allowed to enter a fixed charging station for charging under fixed charging rate,the electric power is filled up and then the distribution task is continued.The objective of the problem is to minimize the total cost by arranging the optimal path,including the cost of power consumption and the cost of vehicle loss.In order to explore the influencing factors affecting the distribution cost of EVRPTW,Genetic Algorithm is used to solve the program.By taking into small-scale examples,EVPTW without charging,EVRP without time windows constraint,EVRPTW at different speed and different charging rates are considered.The experimental results show that:(1)The EVRP with charging station is lower than the EVRP distribution cost without considering the charging station;(2)the existence of the time windows constraint will increase the distribution cost of the EVRP to some extent;(3)the driving of the electric vehicle The faster the speed and charging rate,the lower the distribution cost is.However,the driving speed is usually not constrained by the actual conditions.Therefore,it is necessary to reduce the distribution cost of the electric vehicle considering charging,not only to optimize the vehicle delivery route,but also to make breakthroughs in the charging technology of the electric vehicle,to improve the charging rate,and to reduce the charging time.Therefore,the distribution cost of the electric vehicle is reduced to some extent.