Development of an automated system for continuous ship unloader operation in coal handling

This paper presents the development of an automated operation system for Continuous Ship Unloaders (CSUs), designed to address the complex challenges encountered in unloading bulk cargo such as coal. Autonomous operation has been particularly difficult due to concealed and uneven cargo hold shapes, complex internal structures, and continuous ship motion due to tides and waves, constantly shifting the relative coordinate system. These factors have made precise sensing, safe path planning, and stable control extremely challenging in previous approaches. The proposed system integrates five core technologies: multi-LiDAR-based voxel modeling, heuristic-based path planning, robust path following, feedforward scooping rate control, and hatch-referenced coordinate integration. Unlike previous studies that focused on individual technologies, this paper is, to the best of our knowledge, the first to demonstrate the practical implementation and validation of an integrated automated system in real port operations with various cargo holds and vessel types. The results also show the possibility of retrofitting the system to existing CSUs. The field results confirm both technical feasibility and operational reliability. The system constructs detailed cargo hold 3D models, flexibly adjusts scooping paths according to the detected geometry, and stabilizes the scooping rate by controlling the movement speed. Field evaluation under real unloading operation, including night-time and significant ship sway, achieved 20 minutes of continuous scooping with no unsafe-proximity events and yielded an average scooping efficiency of 97 % relative to the rated capacity, demonstrating that the system maintains stable performance and effective collision avoidance, confirming its practical applicability. These results suggest the feasibility of deploying such systems in smart port environments and demonstrate potential to address labor shortages and enhance safety and operational stability.