Climbing ring robot for inspection of offshore wind turbines

Abstract

Purpose: Structural integrity inspection of offshore wind turbine blades poses problems of gaining access to the blades, danger to human operatives and large costs of removing a blade and transporting it off‐shore for inspection. The purpose of this paper is to show that a climbing robot that can perform in situ blade inspection with micro/nano focus computed axial X‐ray tomography is a solution to find defects in the thickest blade sections and reduce the cost of inspection.Design/methodology/approach: The weight of such an inspection system will be high, typically 200 kg and cross sectional scanner dimensions of 1 × 2 m to envelope a blade. The design of a climbing ring robot that completely encircles a turbine tower, typically 3 m in diameter, will provide the best means of climbing with this payload. Because of the development costs of such a huge robot, the optimal design path is to first prototype a small scale model.Findings: First results on such a model are described and from its performance the load carrying capabilities of a full scale version computed. The robot is able to climb either straight up or down, or with a spiralling motion, or rotate around the circumference at the same height. Furthermore, the design is entirely modular thus enabling easy on‐site assembly of the robot.Originality/value: A climbing robot with high payload and versatile motion capability, with adhesive forces between the robot and climbing surface provided entirely by mechanical means rather than by vacuum suction or magnetic force, making the system much safer and easier to manipulate.