Abstract:

Magnetic-adhesion climbing robots are a promising solution for inspection, maintenance, and cleaning of steel structures such as ships, pipelines, tanks, turbines, and bridges, where conventional manual work is difficult, hazardous, and costly. This paper reviews recent design concepts for magnetic climbing robots reported in the literature between 2020 and 2025, with emphasis on mechanical architecture, adhesion layout, locomotion principle, and the ability to operate on flat, curved, and intersecting surfaces. The reviewed systems were classified according to magnet location, drive type, and surface geometry. The analysis covers robots with magnets integrated into the chassis, robots equipped with magnetic wheels of different configurations, and non-wheeled solutions including walking and crawling robots. Special attention is given to methods of overcoming corners and transitions between surfaces, which were grouped into passive, active, and modular approaches. The review shows that wheeled robots with specialized magnetic wheels remain the dominant concept due to their mechanical simplicity and strong adhesion, while more advanced walking, crawling, and modular systems offer improved adaptability to complex geometries. At the same time, the study identifies key design challenges common to nearly all concepts, especially controlled detachment from the surface, motion across corners and curved structures, and the trade-off between structural simplicity and mobility. These findings help clarify current development trends and indicate the most important directions for future magnetic climbing robot design.