Research On Circular Picking Path Optimization Of Auto Parts Considering Three-Dimensional Loading Constraints

With the rapid economic growth,China’s car ownership is increasing year by year,and the demand of auto manufacturers for auto parts is also increasing.With the increase of pick-up demand,the logistics cost of component entry has become an important factor affecting the overall production cost of enterprises,which promotes enterprises’ demand for efficient and low-cost component entry mode and corresponding planning methods.Milk-Run is a kind of parts pickup mode widely used by many automobile manufacturers in recent years.It is a closed-loop "pull" transportation mode with characteristics of timing,multi-frequency and small batch,which can reduce the logistics cost of parts entry.Compared with the direct pick-up mode based on manual experience adopted by automobile manufacturers in the past,the main difficulty of the circular pickup mode is how to formulate the vehicle pickup path and the corresponding vehicle loading scheme at the same time to minimize the overall pickup cost,that is,how to efficiently solve the three dimensional loading capacitated vehicle routing problem that considers the constraints related to the cyclic pickup mode of auto parts(3L-CVRP).The auto parts pick-up problem is a combination of three-dimensional loading optimization problems and path planning optimization problems,both of which belong to the NP-Hard(Nondeterministic Polynomial-Hard)problem,which is difficult to solve efficiently.In this paper,with the purpose of designing a parts pick-up model and algorithm that can achieve the lowest cost,on the basis of comparing the advantages and disadvantages and applicable conditions of transportation modes such as circular pick-up and direct transportation,this paper studies the comprehensive optimization problem of loadingpath in the circular pick-up mode of auto parts,and the main work is as follows:(1)The theory related to the inbound logistics of auto parts is analyzed.From the aspects of the concept of auto parts inbound logistics,the existing inbound logistics mode,and the relevant theory of the milk-run,the advantages and disadvantages of the current entry logistics mode and the improvement direction are discussed.The current situation of milk-run of parts and components at home and abroad is studied,and the characteristics and difficulties of the milk-run are clarified,and then the research objects and difficulties of this paper are clarified.(2)Overall analysis was made on the parts recycling pickup path problem considering three-dimensional loading constraints.Firstly,the overall problem was described,and then the three-dimensional loading problem and path planning problem in the synthesis problem were analyzed.The specific constraints and solution objectives of the three-dimensional loading problem in the cyclic pickup mode were clarified,and the relevant model of the path planning problem in the circular pick-up mode was established,and finally the overall solution framework of the 3D loading and path planning fusion problem was given.(3)Research on relevant algorithms for three-dimensional loading problems.In order to fully ensure the feasibility of vehicle loading in the recycling pick-up scheme of parts and components,and ensure the successful loading of all vehicles while reducing the cost of recycling pick-up,this paper further considers the three-dimensional loading constraints,and further studies the three-dimensional loading problems in the process of parts and components pick-up in milk-run mode.The micro-evolution algorithm and greedy algorithm were designed to solve the corresponding loading problem,and the solver was used to solve the problem accurately to verify the accuracy of the two algorithms.By comparing the greedy algorithm with the micro-evolution algorithm and the solution obtained by the solver,the validity of the three-dimensional loading greedy algorithm proposed in this paper was further verified.(4)A comprehensive branch pricing algorithm is designed and proposed to study the path optimization method of the circular pickup problem.On the basis of the research of3 D loading algorithm,the framework of branch pricing algorithm is used to design a comprehensive algorithm to optimize and solve the optimization problem of circular pickup path,so as to obtain a circular pick-up path scheme that satisfies both the path and the3 D loading constraints.(5)Case study.The circular pick-up demand of an automobile manufacturing enterprise was selected as a practical research case to verify the effectiveness of the model and algorithm proposed in the paper.