Research On Optimization Of Urban Logistics Distribution Path Based On Small Swap-body Transportation

China’s CO₂ emissions in 2018 have reached 10 billion tons,carbon emissions ranked first in the world,the environmental problems caused by carbon emissions are increasing.At the same time,the relevant departments in China are vigorously promoting the reduction of carbon emissions,more and more individuals and enterprises are beginning to pay attention to carbon emissions.As an important industry of national economy and modern service,urban logistics has responsibility and obligation to control carbon emission.In the urban logistics system,distribution is one of the most basic and main processes,and it is also the link of the largest energy consumption,and road transportation is its main presentation form.As a new type of road transportation,the advantage of small swap-body vehicle transport is flexible service for customers with different road conditions and demand.But in the actual distribution,the situation that causes the customer dissatisfaction because of not fully considering the customer’s request occurs from time to time,also has the carbon emission quantity quantification difficulty,the customer point distribution demand is different,the driver’s working time utilization is insufficient,the car-depot quantity change causes the cost change,as well as the positive reverse logistics integration and so on urgently needs to solve the problem.Therefore,it is necessary and significant to study the optimization of the small swap-body VRP considering carbon emission cost and distribution cost in urban logistics distribution.Based on the above difficult problems,this paper studies several common problems（multi-depots,time window,multi-trip）in urban logistics distribution using small swapbody vehicle.First of all,this paper summarizes the research status of various types of VRP and the optimization of small swap-body VRP.This paper introduces the concept,characteristics and existing problems of urban logistics distribution,analyzes the traditional truck and trail transport and small swap-body vehicle transport,highlights the advantages of small swap-body vehicle transport,and analyzes the factors affecting its cost.In addition,for the calculation of carbon emission cost,the paper deals with the theory of related algorithms,which provides a theoretical basis and technical support for the following research to establish the model solution results.Secondly,in order to achieve the goal of minimum distribution cost after considering carbon emission cost,combined with the characteristics of small swap-body VRP and urban logistics distribution,this paper studies the multi-trip distribution problems of car depot,multi-depots and time window respectively,constructs different mathematical models,designs the improved genetic algorithm（IGA）to solve the small swap-body vehicle single depot optimization model,the improved double chromosome GA to solve the multi-depots model,and the multi-population GA and packing algorithm heuristic algorithm to solve the multi-trip small swap-body vehicle single depot optimization model with time window.Through the comparison experiment,it is proved that the efficiency of the improved GA algorithm is obviously better than that of the traditional GA,so the algorithm designed in this paper is suitable for solving the problem in this paper.Finally,the sensitivity analysis of the starting cost,driving cost and carbon tax of the fifth chapter is carried out.,and the influence degree of different factors on the cost is obtained.The results show that the driver’s salary has the greatest influence on the objective function,that is,the distribution cost,so we need to pay attention to the change of this factor.Sensitivity analysis experiment reminds logistics enterprises and related departments to pay more attention to the impact of driver pay on distribution costs,and provides some guidance and suggestions for urban logistics distribution.