Ensuring the reliability of these skyscraper-sized structures over their lifetime is a difficult challenge—these blades can’t be sent to a hangar in the same way airplanes and helicopters can when it’s time for maintenance. Inspections are performed either with telephoto cameras from the ground or using aerial drones. These methods are reasonably good at finding visible damage but currently lack the ability to detect early, hidden damage.

However, recent innovations in robotics may allow for a pathway to introduce low-cost, high-tech inspections to the market: inspections that can detect deep, subsurface damage.

The DOE Sandia National Laboratories-led Blade Reliability Initiative, funded by WETO, builds upon Sandia’s decades of aviation development experience. On the project, Sandia teamed up with International Climbing Machines (whose portable, remote-controlled devices can scale vertical or inverted surfaces) and Dolphitech (developers of advanced ultrasound cameras for two-dimensional and three-dimensional inspection of materials) to design, build, and validate a crawling robot to conduct automated, full-penetration inspections of wind turbine blades.

Controlled by an operator, the Assessment Robot for Resilient Optimized Wind energy, or ARROW(e), is deployed from the turbine nacelle and suctions itself to the vertical surface of a blade, crawling to where it is needed. Onboard cameras provide real-time, high-fidelity images to detect surface damage while phased-array ultrasonic imaging finds any nonvisible, subsurface damage.