Research On Express Vehicle Routing Problem With Time Windows

Vehicle Routing Problem(VRP)has become one of the most active and successful research areas in the field of operational research in recent decades.As the international community attaches great importance to the development of e-commerce,the express industry has been able to obtain a vast market and further promote the increase in express delivery volume.In spite of this,due to the lack of construction of distribution network nodes,the backwardness of command and dispatch systems,and the lack of scientific management and control of the evacuation system,high-cost,low-efficiency,and poorer transport consistency have been caused.Vehicle Routing Problem with Time Windows(VRPTW)can better reflect the actual situation of express service than VRP which only contains vehicle load constraint.Based on the low efficiency of express distribution and the time-effectiveness of express,the research and application of this issue have important theoretical and practical significance and can significantly reduce the distribution cost of express enterprises.Based on the previous research,this paper focuses on the modeling technology and genetic algorithm coding scheme.The main research contents are as follows:First,build an optimization model.According to the survey of the delivery problem that the demand for a single express outlet exceeds the maximum vehicle capacity during the peak season or special holidays of the express enterprises,the model of transportation route arrangement in the area by express vehicles with unilateral time windows constraint,the combination of circular distribution and full load direct delivery is built.Second,genetic algorithm design.According to the characteristics of the model,the penalty function method and specific real value coding are used to deal with the distribution center capacity constraints,vehicle capacity constraints,time window constraints and other constraints.In order to ensure that the algorithm has a good search performance,operators are selected,the stochastic universal sampling and the adaptive interpolation method;the genetic operations combined with the multi-point crossover and variation mutation rate methodmulti-point crossover method are used to better complete the optimization process and prevent the genetic algorithm from converging prematurely.Third,application and numerical results.The relevant data of transport vehicles and express business outlets are given,according to the design of the genetic algorithm,through the MATLAB programming,calculation can obtain a satisfactory solution,the ideal transportation route plan and a higher operational efficiency are given;to focus on the parameter setting,this paper analyzes how it affects the algorithm and validates the model and algorithm to show its feasibility and effectiveness.On the basis of this,this paper proposes application countermeasures so as to provide auxiliary decision-making tool for express enterprises to improve delivery efficiency and reduce transportation costs.