Optimization Of Resource Allocation And Equipment Scheduling In Automated Container Terminals Considering Tandem Quay Cranes

As a key component to building a world-class seaport logistics hub,container terminals are continuously improving and innovating their operations and technology.In order to adapt to the trend of larger vessels,some large container ports have begun to introduce tandem quay cranes for loading and unloading operations.The tandem quay crane is a new type of advanced loading and unloading equipment that can handle two 40 ft containers or four 20 ft containers in a single operation.Compared with traditional single-spreader quay cranes,the tandem quay crane can reduce ship loading and unloading time by nearly 50%,and has significant advantages in shortening the ship’s turnaround time in port,and enhancing the overall competitiveness of the port.However,the dual-spreader mechanism of the tandem quay crane is limited by the load capacity,adjacent placement,and synchronous loading and unloading,making it difficult to fully utilize its design efficiency with traditional terminal equipment scheduling methods.Therefore,studying the scheduling methods for the container terminal considering tandem quay cranes is urgent.With the evolution of automation and informatization characteristics in modern container terminals,to further promote the innovation process of the mechanical equipment,this study takes automated container terminals as the background and designs a set of resource allocation and equipment scheduling methods suitable for tandem quay crane operations.The research work is summarized as follows:(1)Research on the optimization of quayline resource allocation in automated container terminals considering tandem quay cranes is conducted.Considering two types of quay cranes and traffic congestions in the container terminal,a multi-objective nonlinear programming model with the objectives of minimizing the ship delay cost and AGV transportation cost(considering congestions)is established,to achieve coordinated decisions on berth assignment,multiple-type quay crane allocation,and AGV path allocation.A two-stage algorithm based on the Frank-Wolfe method is designed to solve the problem.Experimental results show that by considering traffic congestions in allocating berths and quay cranes,the average AGV transportation cost can be reduced by 24.7%,verifying the effectiveness of the proposed method.This research focuses on the optimization of quayline resource allocation before the ship arrivals at the port,laying the foundation for the research on the equipment scheduling in container terminals.(2)Research on the optimization of tandem quay crane scheduling considering spreader changeovers is conducted.Considering the operational characteristics of tandem quay cranes,an integer programming model is established to minimize the quay crane operational time,which can make coordinated decisions on the operational modes,the unloading sequence,and the timing of spreader changeovers of the tandem quay cranes,followed by valid inequalities to accelerate the model.A logic-based Benders decomposition algorithm is designed to solve the problem,acceleration rules based on the single-stack and multi-stack,as well as upper bounds are proposed.Numerical experiments show that the algorithm can obtain the optimal solution of real-scale instances quickly.This research focuses on the scheduling methods of the tandem quay crane,laying the foundation for the research on the collaborative scheduling of multiple equipment in container terminals.(3)Research on the collaborative scheduling of multiple equipment in container terminals considering tandem quay cranes is conducted.First,based on the impact of the yard block allocation on the scheduling plans of operational equipment during the unloading process,with the objective of minimizing the completion time of the tandem quay crane unloading operations,a collaborative optimization model is established for scheduling tandem quay cranes and AGVs,where the yard space allocation of containers is also considered,and a multi-start variable neighborhood search algorithm is designed to solve the problem.The experimental results show that the collaborative method can effectively enhance the coordinated ability between AGVs and tandem quay cranes.Second,based on the impact of the containership stowage plan on the scheduling plans of operational equipment during the loading process,with the objective of minimizing the completion time of the tandem quay crane loading operations,a model for collaborative optimizing containership stowage plans,tandem quay crane operational modes,AGV scheduling plans,and yard crane operational sequences is established,and a greedy random adaptive search algorithm is designed to solve the problem.Numerical experiments show that when the number of AGVs is relatively sufficient,the tandem quay crane can improve the loading efficiency by 31.5% than that of traditional quay cranes,which is very close to the theoretical value(32.5%)that we set.In summary,this study focuses the operational characteristics of tandem quay cranes and conducts research on the methods of resource allocation and equipment scheduling in automated container terminals.The research can fully utilize the designed efficiency of tandem quay cranes,improve the loading and unloading efficiency of automated container terminals,and provide theoretical support for the promotion of the application of tandem quay cranes in container terminals as well as the efficient operations in automated container terminals.