Synchronous Scheduling and Vehicle Optimization of In-Plant Parts Transport Under Bidirectional Loading-Unloading

Abstract

Aiming at the bidirectional closed-loop transport scenario between the auto parts logistics center and the complete vehicle factory in the in-plant logistics of automobile original equipment manufacturers (OEMs), this paper constructs a synchronous scheduling optimization model for tractors and trailers with hard time windows, to address the problems of long vehicle waiting time, low utilization rate and high operating cost in the traditional integrated transport mode. The model takes the completion of daily transport tasks as the hard constraint, takes the minimization of the total daily operating cost of tractors and trailers as the optimization objective, and fully considers the decoupling operation characteristics of tractors and trailers in bidirectional loading and unloading operations. Aiming at the NP-hard property of the model, a Tabu Search algorithm adapted to the two-point bidirectional scenario is designed. The feasibility verification of the solution is implemented through event-driven simulation based on greedy strategy, and global optimization is realized by combining neighborhood search rules, tabu list and aspiration criterion. Finally, a numerical example analysis is carried out with the actual operation data of an automobile OEM. The results show that, under the scenario with a daily transport demand of 50 vehicle trips and an effective working time of 480 minutes, the model and algorithm proposed in this paper can quickly obtain the optimal vehicle configuration scheme. Compared with the traditional integrated truck transport mode, the proposed method reduces the operating cost by 38.07% and increases the tractor utilization rate by more than 80.66%, which verifies the correctness of the model and the effectiveness of the algorithm.