| The logistics of many industries from the traditional single distribution mode(single delivery,single pick-up)gradually to the integration of pick-up and delivery distribution mode,in order to achieve the purpose of cost reduction and efficiency.However,in most cases,there will be a lot of loading and unloading operations at the service point,which may lead to unreasonable space arrangement in the carriage,cargo cannot be placed,cost increases and other problems.Therefore,during the period of pick-up and delivery,it is very critical for the overall efficiency of logistics transportation to formulate the placement plan of the goods in advance and arrange the appropriate path,and do not move the goods in the car again at the non-unloading point.When the goods are significant,fragile or dangerous,it is particularly important to comply with the three-dimensional loading and unloading constraints,so as to ensure the safe handling and protection of the goods.In this paper,three-dimensional loading(3D-BPP)and path planning problem(PDP)in pick-up and delivery business are combined to provide a one-stop solution.The work and innovation are as follows:(1)Design and solve the solution of three-dimensional packing and path planning problem of take-and-send integration and establish the model.The solution is divided into three dimensional preloading stage and path planning stage,and models are established for the two stages respectively.The three-dimensional preloading stage model aims at the minimum carriage length occupied by goods at the pick-up point,while the path planning stage model aims at high space utilization rate and low total cost,and comprehensively considers the weather and road conditions,time window and other factors.(2)three-dimensional preloading phase solution.This stage mainly solves the three-dimensional packing problem of the goods set at the pick-up point.Through improving the Pisinger tree search,three-dimensional packing was carried out to construct layers of goods "walls".Four functional components,namely dynamic dictionary,wall replication,wall memory and wall reloading with low space utilization rate,were designed for the tree search process to improve the search quality,fit the business requirements,and improve the pairing way of goods.After the cargo collection is preloaded at the pick-up point,the occupied compartment space is converted into the total length occupied by the compartment,the outermost length(the length that can be reduced),and the width occupied by the outermost compartment.(3)Solution in path planning stage.In this stage,order allocation and route planning of several vehicles are mainly solved.Vehicles pass through a route that is constrained by mixed time window,loading and unloading,weather and road,and complete all pickup and delivery order requirements.At this stage,the solution is to improve the carnivorous plant algorithm population optimization plus individual local search.The initial population was generated by task allocation based on chaos and greedy random construction,and the improved carnivorous plant algorithm was used for population optimization.According to the algorithm,the rank ranking,adaptive attraction and change of growth operation were designed to fit the problem requirements,and local search was used for individuals to explore the neighborhood solution and improve the search accuracy.After several iterations,the final scheme was obtained.(4)In order to verify the application effect of the scheme in the model,the open data set is used to simulate and compare the scheme with other algorithms.The experimental results show that the scheme can solve the problem effectively and has strong practicability.(5)According to the architecture,module,database design and specific business requirements of the three-dimensional packing and routing system of the take-and-delivery integration,the system is divided into the mobile terminal(APP)of cargo owners and drivers and the background administrator system(Web)of the company,and the front and back end development and testing are carried out respectively.The test results show that the system functions well and provides technical support for the realization of pick-up and delivery business. |
