Research On The Distribution Route Problem Of Emergency Supplies In Series Mode Of "Vehicle-Drones"

In recent years,global natural disasters,public health events and other emergencies have occurred with high frequency.Rapid improvement of rescue efficiency is the core task of emergency rescue.In order to reduce the death rate of the people in the disaster areas and reduce the impact of disasters on the life safety of the affected people,the timely delivery of emergency supplies has become crucial.Reasonable arrangement of the distribution route of emergency supplies can effectively improve the efficiency of rescue,so it is of certain value to study the distribution route of emergency supplies.At present,most of the existing literature studies the pure vehicle route problem of emergency supplies distribution.Considering the road conditions in disaster areas and the urgent demand for emergency supplies,this paper will study the route problem of tandem "vehicle-drones" joint distribution of relief supplies,so as to improve the rescue efficiency of the emergency logistics system.Firstly,the paper analyzes the relevant literature about the vehicle routing problem of emergency supplies.Considering that some logistics vehicles cannot pass in the short term due to road damage,this paper proposes the problem of emergency supplies distribution route based on the series mode of "vehicle-drones".Based on this,a mathematical model of Hybrid Vehicle-Drone Routing Problem(HV-DRP)is established.In this model,the vehicle acts as a mobile station,carrying the drone and relief supplies from the warehouse to visit the vehicle station(an intermediate station).The vehicle launches the drone at the site,and when the drone has finished serving the affected area,it picks up the drone at the same site or another site.The vehicle and drone are required to coordinate in time,which means the vehicle must synchronize with the drone when launching or receiving it.The model aims to minimize the total waiting time at the disaster site,while considering the maximum carrying capacity and endurance time constraints of the drone.In addition,a small scale example is solved with a LINGO solver to verify the effectiveness of the mathematical model presented in this paper.In this paper,we study the nonlinear integer programming problem,HV-DRP,which is NP hard problem.It is impossible to use accurate algorithm to solve large-scale problems in a short time,so this paper designs parent genetic algorithm(PGA)to solve examples of different scales.The algorithm mainly includes two layers: in the first layer,the vehicle route is constructed;in the second layer,the drone route is constructed on the basis of obtaining the sequence of vehicle stops.From the results,the PGA used to solve the mathematical model of this paper has advantages in the quality,speed and stability of the solution.So the PGA has certain feasibility and effectiveness.Finally,the HV-DRP problem proposed in this paper is compared with the pure vehicle routing problem(VRP).The results show that the series mode of "vehicle-drones" can reduce the sum of waiting time at the disaster site and improve the rescue efficiency compared with the pure vehicle mode.Therefore,the model and algorithm proposed in this paper can provide theoretical support and practical basis for the study of emergency logistics and vehicle-drones joint distribution route problem.