Design and application of a wall-climbing robot for paint removal and grinding in weld zones on the outer wall of large spherical tanks

To address issues such as environmental pollution, high labor intensity, and insufficient adaptability of traditional robots in paint removal and grinding operations for weld zones on the outer walls of large spherical tanks, this paper proposes a triangular-structured wall-climbing robot integrating ultra-high-pressure water jet and magnetic adsorption technologies, aiming to achieve green, efficient, and safe automated grinding. The triangular structure enhances robot stability and load capacity. By optimizing the magnetic adsorption structure with a Halbach array, the magnetic force of curved magnets at a 4 – 10 mm distance from the tank wall is increased by an average of 37% compared to flat magnets, resolving the challenge of stable adsorption on curved surfaces. A sealing solution for the grinding recovery disk straddling welds and a dual-robot coordinated offset navigation strategy are proposed, enabling large-area grinding and wastewater recovery within 200 mm on both sides of welds. Experiments show that the robot has an overall height of 420 mm, a maximum travel speed of 13 m/min, and a grinding efficiency of 38 m 2 /h, meeting post-grinding nondestructive testing requirements. Engineering applications demonstrate that the robot can replace manual labor in paint removal and grinding tasks on the outer weld zones of a 5000 m 3 propylene spherical tank, significantly improving efficiency and reducing environmental pollution.