Design and motion adaptability analysis of a triangular-tracked wall-climbing robot for hull curved surfaces

Purpose This study aims to address safety hazards and inefficiency in high-altitude operations on curved ship hull surfaces by designing a triangular-tracked wall-climbing robot. The robot enables automated and safer maintenance for ship exterior surfaces. Design/methodology/approach Existing design challenges for ship wall-climbing robots were analyzed. A modular lightweight structure, integrated with a triangular-tracked driving system and a permanent-magnetic adsorption device, was proposed to enhance surface adaptability. Spatial posture models and mechanical analysis models for four typical failure modes (slippage, longitudinal/lateral overturning and normal detachment) were established and the torque demand model was analyzed. Robot performance was evaluated through simulations and experimental validations on convex (R = 4m) and concave (R = 3.5m) surfaces, including load testing. Findings Simulation results indicate that the minimum requirements for safe operation are a magnetic adsorption force of 758 N and a drive torque of 50.23 N·m. Experimental validation confirmed that the developed prototype, with a self-weight of 28.8 kg, generates a total magnetic adsorption force of 1,376.2 N and a rated output torque of 128 N·m, significantly exceeding the design requirements. During field tests on convex (R = 4m) and concave (R = 3.5m) surfaces, the robot demonstrated stable locomotion and successfully carried a 280 N payload, achieving a high payload-to-self-weight ratio of 0.972. Originality/value The innovation lies in proposing a triangular-tracked structure to enhance surface adaptability, establishing critical adsorption force models for the four failure modes, analyzing the selection criteria for the driving system and constructing a ship-hull-mimicking convex–concave experimental platform. This work provides theoretical foundations and engineering solutions for hull maintenance robots, significantly improving operational safety and efficiency on complex curved surfaces.