Inchworm-inspired climbing robot for steel structures with three bionic operating modes

Steel climbing robots have been utilized to assist manual inspection in recent years for ensuring the reliability of steel structures. However, existing steel climbing robots face significant challenges in efficiently navigating and inspecting complex and confined steel structures. In response, this paper proposes a steel structure climbing robot inspired by the inchworm with three working modes, enabling fast crawling in open spaces, slow creeping in confined spaces, perpendicular surface switching, crossing obstacles, and manipulation capabilities. Climbing and manipulation capabilities of Tribot are analyzed and evaluated by experiments. Tribot achieves step distances of 270 mm and 60 mm in fast crawling mode and slow creeping mode. In manipulation mode, Tribot shows a good 4-DOF manipulation capacity with a carrying load of 1 kg. Obstacle crossing experiments demonstrate that the Tribot can traverse the U-ribs with a height of 260 mm and shows a climbing surface switching capacity between 0° and 180°.