Purpose - The paper aims to develop a robot that climbs on non-ferrous surfaces, e.g. aircraft wings and fuselages, carrying a heavy payload up to 18 kg including scanning arm and various equipments, for non-destructive testing (NDT). Design/methodology/approach - This robot in the study uses vacuum suction cups for adhesion, and two pairs of pneumatic cylinders to drive itself, moving in two directions in stepping gait. A rotation mechanism in the centre is used to correct the off-course deviations by +/- 5 degrees. Multiple universal joints are used to make every single suction cup, every robot foot and the whole structure flexible to negotiate with varying surface curvatures presented in different parts of aircraft. This flexible structure is also rigid once the robot is stuck on the surface to enable the NDT inspection being carried out reliably. Findings - The paper finds that the walking speed is limited by the cylinder stroke, time for generating vacuum and changing legs. Although most NDT inspection is time-consumable, it is still desirable to increase the robot speed. Practical implications - The application of this robotic NDT can significantly reduce the cost of aircraft inspection, eliminate labour-intensive and monotonous inspection tasks and eliminate the need for an operator to work in confined and dangerous spaces. Originality/value - The paper introduces the structure that combines flexibility and rigidity for a robot climbing on non-ferrous curvatures.
