Research On Joint Distribution Route Of Low-carbon And Cold Chain Logistics Under Time-varying Road Network

Cold chain logistics is an important part of the logistics industry,but from the overall development status of cold chain logistics,the development of cold chain logistics is still at a relatively low level in my country.On the one hand,cold chain logistics has the characteristics of high energy consumption and high carbon emissions in the distribution process,and the purpose of developing low-carbon logistics is to reduce carbon emissions,so it restricts the development of cold chain logistics;on the other hand,due to Urban traffic congestion is becoming more and more serious,and the circulation process of cold chain logistics products is cumbersome,which increases the wastage rate of cold chain products and increases logistics costs.At the same time,the state advocates the concept of green and low-carbon development,and encourages cold-chain logistics enterprises to carry out innovations in business models such as joint distribution,the combination of fresh food e-commerce and cold-chain distribution to home,so as to improve the service level of urban cold-chain logistics and distribution.Therefore,this paper studies the joint distribution path problem of cold chain logistics considering carbon emissions under the time-varying road network.(1)Construction of a joint distribution path optimization model for low-carbon cold chain logistics under the time-varying road network.First of all,in view of the problem that the speed changes all the time in the process of cold chain logistics distribution under the time-varying road network,which makes it difficult to calculate the travel time,a time calculation model for cross-time distribution and a time calculation model for non-cross-time distribution are established respectively.Quantify carbon emissions,analyze the fuel consumption model when the vehicle is running,and determine the comprehensive fuel consumption calculation model related to speed and load;on this basis,make reasonable assumptions about the problem,and then focus on distribution The time factor in the process is constrained by the vehicle load,time window,etc.,and comprehensively analyzes the fixed cost of the vehicle,transportation cost,cooling cost,penalty cost,cargo damage cost,carbon emission cost,etc.in the distribution process.Constructing a joint distribution path optimization model for low-carbon cold chain logistics under the time-varying road network.(2)The design of the path optimization model solving algorithm.Firstly,the basic principle and operation steps of the standard particle swarm optimization algorithm are introduced,and the relevant parameters are analyzed and explained;then the particles are encoded and decoded according to the problem solved in this paper,and the population initialization is carried out by introducing chaos theory to avoid the initial particle distribution.It is uniform and falls into a local optimum.At the same time,the convergence performance of the adaptive variable inertia weight control algorithm and the genetic operator(crossover operator,mutation operator)are used to increase the diversity of particles,and an adaptive variable inertia weight is designed.The hybrid particle swarm algorithm.(3)Select three cold chain logistics enterprises in W city for example analysis,bring in relevant data,carry out simulation analysis through MATLAB programming,and obtain the optimal path for joint distribution of low-carbon cold chain logistics under the city’s timevarying road network,distribution time,load capacity,distribution distance and distribution cost,and compared with the optimal route,distribution time,load capacity,distribution distance and distribution cost of individual distribution,the results show that the joint distribution strategy has more advantages in all aspects.It is verified that the established model and the designed algorithm are reasonable and effective.