Optimization Of Cold-chain Logistics Drop And Pull Transport Scheduling Considering The Spare Trailer

China is a large import and export country of fresh agricultural products.In 2017,the import value of only fruits and vegetables reached US$9.515 billion,and the export volume was as high as US$24.222 billion.The huge import and export trade needs strong logistics support as a stand-by.In recent years,the drop and pull transport has gradually been on the right track under the strong promotion of enterprises and the government.As an advanced road transport organization,drop and pull transport has made significant contributions to not only improving vehicle utilization,reducing logistics,but also transportation costs,it strengthening resource utilization and emission reduction.At the same time,with the development of the economy,people's consumption concepts have gradually shifted to healthy eating and rational matching,the quality requirements for fresh and perishable products such as fruits and vegetables are also getting higher.This paper proposes an innovative model for placing spare trailers at customer points.This paper adopts a more reasonable empty container transportation strategy and tractor configuration plan,study how to arrange a reasonable tractor scheduling plan for the Collection and transportation of fresh agricultural products between the dock yard and the cold storage of the port hinterland under the cold-chain logistics drop and pull mode.In this paper,the loss of goods and the energy consumption of reefer containers are included in the total cost.A mathematical model with the minimum objective cost of hanging transportation is proposed.Compared with the traditional drop and pull transportation scheme,it is verified that the trop and pull transportation scheme can effectively reduce the quality loss of fresh agricultural products during the collection and transportation of the port and inland hinterland.