Literature Review on Digital Twin-Based Container Stowage Optimization for Quay Crane Micro-Movements

The efficiency of loading and unloading operations at container terminals is heavily influenced by the performance of Mobile Harbor Cranes (MHCs). While existing stowage plans prioritize vessel stability and terminal throughput, they often fall short in optimizing MHCs' micro-movements—specifically lateral travel and head positioning during container handling. These inefficiencies lead to unnecessary crane motions, extended operation times, and increased energy consumption. Although digital twin technology has been shown to improve yard operations and manage scheduling uncertainties across multiple equipment types, its application in directly minimizing MHC micro-movements through optimized stowage planning remains underexplored. This study proposes a digital twin-based approach focused on quay-side operations by simulating crane movements in a virtual quay environment. Using forward and backward motion modeling, the method replicates realistic crane dynamics and enables detailed analysis of lateral and head movement patterns. The objective is to determine stowage or loading/unloading plans that minimize performance metrics such as total lateral movement and unnecessary head repositioning time. By enabling planners to visualize the operational impact of various stowage scenarios, this approach supports more informed decisions and enhances quay efficiency, equipment lifespan, and energy savings. The study further evaluates related simulation-based models to assess the effectiveness of the proposed methodology in optimizing MHC operations.