Research On Electric Refrigerator Vehicle Routing Problem For Fresh Food

With the rapid development of productivity level and the improvement of consumers' income,regional scale output and off-season sales volume of fresh food is greatly increased.Consumers pay attention to the variety,safety,nutrition of fresh food,especially the quality of fresh food and delivery on time.Fresh food has the characteristics of short life cycle and high perishable rate,so cold chain logistics is very important for ensuring the quality of fresh food.Due to the late start of cold chain logistics in China,route planning mostly depends on driver experience that lacks scientific theory guidance.This leads to the high cost of the fresh food distribution,severe damage of goods and delivery delay which make logistics providers face tremendous pressure.With the increasingly severe damage of air pollution and energy crisis,more and more attention has been paid to electric vehicle with zero emissions and high energy utilization.Electric vehicles not only help to optimize the energy structure and reduce the pressure of traffic pollution control,but also get many national subsidies.For logistics providers of fresh food distribution,electric refrigerator vehicles are environmentally friendly and cheap to travel,so they are suitable choices for future vehicles of fresh food distribution.Routing problem is the key link of measuring cold chain logistics efficiency.The scientific and reasonable route planning theory for electric refrigerator vehicles can effectively shorten the time of the fresh food distribution and reduce the cost of logistics.Unlike the traditional fuel refrigerator vehicle,the electric refrigerator vehicle is powered by the battery directly.So the electric refrigerator vehicles have some characteristics,such as: the limited battery capacity,the longer charging time and the inadequate charging facilities.These characteristics make the electric refrigerator vehicle routing problem not only need to consider the loss of fresh food,but also take into account the charging time,the position of the charging station and the limitation of capacity.The traditional vehicle scheduling theory is not suitable to guide the route planning of electric refrigerator vehicles with fresh food distribution,and logistics providers of fresh food distribution urgently need the theory of electric refrigerator vehicles as the research object.This paper mainly studies electric refrigerator vehicle routing problem for fresh food.First,this paper introduces the literature of electric vehicle routing problem and cold chain logistics.The solving algorithms of the vehicle routing problem are also analyzed.Then,considering the characteristics of fresh food distribution and electric refrigerator vehicle,the minimum number of target functions based on total cost is established,which includes fixed cost,driving cost,refrigeration cost,time window penalty cost and the damage cost of fresh food.After analyzing constraints of vehicle routing problem that includes load constraints,battery capacity constraints and time constraints,the EVRPSTW mixed integer programming model is built.EVRPSTW means the electric vehicle routing problem with soft time window.Then considering that the vehicle scheduling problem is a NP problem,the particle swarm optimization algorithm(PSO)for solving the EVRPSTW problem is presented in this paper.According to the research question,this paper improves algorithm parameters and designs particle coding.Finally,the optimized particle swarm optimization is used to program the EVRPSTW problem on the MATLAB software which includes 60 customer points.Simulation results show that the algorithm can solve EVRPSTW problem steadily and verify the feasibility of PSO algorithm in solving EVRPSTW problem.The change of route and cost with multi-vehicle mixed distribution is also analyzed.The related factors such as w,population quantity in PSO algorithm and time window,battery capacity in the EVRPSTW model are studied.Based on the research,some suggestions for fresh food logistics providers are given from different angles.