Research On Green Vehicle Routing Problem With Two-dimensional Loading Constraint

During the transportation of logistics,Vehicle Routing Problem possesses wide practical foundation and the value of economical application.Over the years,it has been one of research hotspots in logistics academia.In many branches,capacitated vehicle routing problem is one of the most common and important problem in VRP.In the actual transportation,the items demanded by customers are usually fragile,which has high requirement when packed into vehicles.This is called Two-Dimensional Container Loading Problem.Therefore,this is a new problem that combine the two classical problems of vehicle routing problem and two-dimensional container loading problem,called Vehicle Routing Problem with Two-Dimensional Loading Constraints,to improve the efficiency and effect of transportation.Moreover,the environmental pollution caused by logistics activities has been increasingly prominent.Promoting modern logistics to reduce transportation costs,save energy,reduce pollution is an urgent need to improve the efficiency of logistics.Therefore,2L-CVRP considering the fuel consumption has the theoretical value and practical significance.For distribution network with one distribution center,multiple vehicles,multiple customers,multiple items loading,two kinds of optimization problems were put forward,one with 2L-CVRP,and established a Model I taking distance as an object,the other with 2L-CVRP considering the fuel consumption,and established a Model ?taking fuel consumption as an object.The models determine the optimal vehicle driving scheme and goods packing plan.The selection of path and the arrangement of loading are integrated to optimize considering the influence of fuel consumption,which conforms the trend of environmental logistics.For the solving of the two optimization model,this paper designs Particle Swarm Optimization algorithm nested Local Search,and solve it by broking them down into two sub-problems of two-dimensional container loading optimization problem and vehicle routing optimization problem.PSO-LS include two parts.For vehicle routing optimization problem,this paper has designed the PSO based on Greedy Algorithm,to determine the path of vehicles,using Greedy Algorithm to deal with the constraints of capacity.For two-dimensional container loading optimization problem,this paper has designed the LS based on Bottom-Left-Fill Algorithm,to determine the scheme of loading,using BLF to judge the feasibility of loading.The experimental results show the distance of Model II is a little longer than that of Model I,but it saves the fuel consumption,which not only has the fuel saving potential but also reduces the pollution of the environment.In addition,the convergence speed of PSO-LS is fast in the process of solving problem.