Tractor Scheduling Problem Of Network-type Drop And Pull Transportation

Logistics industry is a composite service industry which integrates warehousing,transportation,packaging and other industries.Its development directly affects the process of transformation and upgrading of related industries.It is also an effective way to promote supply-side reform and improve the efficiency of economic operation.The development of modern logistics is inseparably from efficient transportation.Among them,the organization mode of highway transportation represented by drop-and-pull transportation is one of the important measures to realize efficient freight logistics and improve the rational allocation of road resources.At present,drop-and-pull transportation in China is just getting started and having a slow development.In the actual transport process,there is a lack of scientific,rational and efficient scheduling scheme.In this regard,this dissertation combines the characteristics of road traffic network-based drop-and-pull transportation and the studies of the vehicle scheduling problem.The drop-and-pull scheduling is determined.Firstly,through the overview of drop-and-pull transportation,the mode of transportation in this paper is defined as the combination of tractor and trailer,which can be used in the field of road transportation.After that,combined with the introduction of the organization mode of drop-and-pull transportation,the characteristics of network-type drop-and-pull transportation,with multi-depots,multi-operation points and vehicle routing network are determined.This paper summarizes the characteristics and problem types of network-based vehicle scheduling,from the perspectives of task type,tractor status and trailer type.On the basis of the characteristics and types of network-based drop-and-pull transportation,transport scenarios are designed,while the constraints are concretized and mathematicized according to the description of transport scenarios.In the stage of model building,the model of multi-depot drop-and-pull transportation is built,and then extended to the model of multi-depot and multi-type drop-and-pull transportation.In the algorithm design part of the model,two-stage heuristic algorithm is determined.Firstly,the multi-depot problem is transformed into a single depot problem,and the variable neighborhood search algorithm based on simulated annealing is used to find the vehicle routing that satisfies the customer’s transport needs and constraints.Then,the tractor can be allocated to each depot by using dynamic programming algorithm to obtain the optimal solution of the multi-depot trailer transport problem.Finally,the tractor scheduling problem of network-type drop-and-pull transportation is illustrated by combining enterprise examples.Firstly,the enterprise’^drop-and-pull transportation in situation is improved,but the optimization effect is unsatisfactory.The author considers that the main factor restricting the transport of tractors is lying in the insufficient number of trailers at operation points.In this regard,two scheduling schemes of rental trailer and dispatching trailer are proposed.Then,from the points of operation cost and operation efficiency,this paper compares three kinds of drop-and-pull transportation scheduling modes,and confirms that it is more appropriate for the enterprise to adopt the dispatching scheme of trailer leasing under the current situation,and puts forward corresponding suggestions on the future network-type drop-and-pull transportation.Figure 33,Table 25,Reference 86.