Design and Analysis of a Novel Magnetic Adhesion Robot with Passive Suspension

The steel lining of large facilities is an important structure that experiences extreme environments and requires periodical inspection after manufacture. However, due to the complexity of their internal environments (crisscross welds, curved surfaces, etc.), high demands are placed on stable adhesion and curvature adaptability. This paper presents a novel wheeled magnetic adhesion robot with passive suspension named NuBot, which is mainly applied in nuclear power containment. Based on the kinematic model of the 3-DOF independent suspension, a comprehensive optimization model is established, and global optimal dimensions are properly chosen from performance atlases. Then, a safety adhesion analysis considering non-slip and non-overturning condition is conducted to verify the magnetic force meet the safety demand. Experiments show that the robot can achieve precise locomotion on both strong and weak magnetic walls with different inclination angles, and can stably cross the 5 mm weld seam. Besides, its maximum payload capacity reaches 3.6 kg. Results show that NuBot has good comprehensive capabilities of surface-adaptability, adhesion stability, and payload. Besides, the robot can be applied in more ferromagnetic environments with more applications and the design method offers guidance for similar wheeled robots with passive suspension.