A wind inspector calls

German researchers at the Fraunhofer Institute for Factory Operation and Automation IFF have developed a robot that can automatically inspect the condition of wind turbine rotors.

In operation, the robot pulls itself up a rope until it reaches the turbine's rotor blades.

Then it inspects every centimetre of the rotor blades’ surface, registering any crack and any delamination in the material before relaying their exact positions back to an operator.

Primarily made of glass-fibre reinforced plastics, rotor blades have to withstand a great deal: wind, inertial forces and erosion.

Until now, humans have inspected them at regular intervals, which is not an easy job.

'Our robot is equipped with a number of advanced sensor systems.

‘This enables it to inspect rotor blades closely,' said Dr Norbert Elkmann, project manager at Fraunhofer IFF.

The inspection system consists of three elements: an infrared radiator conducts heat to the surface of the rotor blades.

A high-resolution thermal camera records the temperature pattern and thus registers flaws in the material.

In addition, an ultrasonic system and a high resolution camera are also on board, enabling the robot to detect damage that would remain hidden to the human eye.

A specially developed carrier system ensures that the inspection robot is guided securely and precisely along the surface of a rotor blade.

One major advantage of the system is that it can perform its job on any wind energy converter, regardless of whether it is large or small, on land or offshore.