
Robotic disc cutter grasping in tunnel boring machine (TBM) maintenance is challenged by large initial pose uncertainty, occlusion, and harsh underground sensing conditions. This paper proposes a coarse-to-fine uncertainty reduction framework that progressively refines the grasp pose of heavy disc cutters. A coarse stage localizes the cutter under substantial initial uncertainty, while a fine stage reduces residual pose errors through multi-sensor fusion and adaptive grasping control. The approach improves grasp reliability for automated cutter replacement and is validated in TBM-oriented experimental settings.