Research On The Route Problem Of Express Delivery Vehicles With Soft Time Window Under The Influence Of Velocity Fluctuation

For the study of vehicle path problem,it is often considered that the speed is constant or time varying,and the final result is a certain driving time.However,according to previous experience,the average speed of the vehicle in a certain section of the road will not be constant,nor can it be accurately mastered in advance,but will generally fluctuate within a certain range.The fluctuation of speed will directly affect the vehicle travel time,resulting in the uncertainty of the vehicle travel time between nodes,which is very important when studying the VRP problem with soft time window.In order to study the vehicle speed fluctuation influence on vehicle distribution costs and path,this article introduced the vehicle average speed distribution function,calculates the vehicle reaches the customer point of time and with the customer,in comparison with the desired time window analysis of possible situations and get the corresponding time cost expression,finally construct the objective function based on the distribution of the lowest cost,including vehicle fixed cost,traffic cost and time cost.Considering the characteristics of the model,the improved genetic algorithm was used to solve the problem.Based on the actual distribution situation,this paper studies the VRPSTW problem of the fluctuation of the speed of urban express delivery vehicles.The research methods and contents are as follows:(1)First of all,aiming at the problem of distribution vehicle speed fluctuation,this paper introduces the vehicle average speed distribution function,the resulting vehicle arrives customer point of time,based on the vehicle fixed costs,transportation costs and time of the lowest total cost mathematical model for vehicle routing problem with soft time Windows,the improved genetic algorithm and design.(2)Through the analysis of calculation examples,the calculation results are compared with the distribution scheme of the path problem with constant vehicle speed.The experimental results show that the fluctuation of vehicle speed is considered when the average speed of the vehicle is unchanged.(3)Summarized the main contents and shortcomings of the paper,and looked forward to the future research direction of the paper.