A Flight–Attachment–Crawling Robot for Large-Scale Crane Inspection: Design, Aerodynamic Analysis, and Experiment

This paper presents a flight–attachment–crawling robot (FACR) for close-range inspection of large-scale crane structures, aiming to improve access efficiency and contact-based inspection capability in elevated and discontinuous metallic environments. The proposed robot integrates flight, magnetic attachment and crawling units. To clarify the multimodal operating mechanism, dynamic models are established for the flight, wall-supported locomotion, and wall-attachment modes. Computational fluid dynamics simulations are then conducted to analyze near-wall aerodynamic effects, including the influence of wall proximity and lateral-rotor activation on rotor wake interaction, lift variation, and wall-normal support. A prototype platform is developed, and representative staged experiments are carried out to evaluate multimodal operation. The results show that the proposed FACR can support key multimodal operating stages required for crane-oriented inspection and provides a feasible platform-level solution for combining aerial mobility, wall-surface operation, and fixed-point attachment in complex industrial environments.