Meet the BR-8 robot that inspects and repairs wind turbine blades
Wind energy continues to drive the energy revolution. In 2020, the total installed wind energy capacity reached 458 TW, equivalent to supplying 16 % of electricity demand, and the capacity is expanding every year. Wind turbines are also getting larger and taller to increase aerodynamic efficiency and generate more power. However, the quest for larger structures comes with its fair share of challenges. “The longer the blade, the greater the tip speed – and the higher the erosion rate on the leading edges,” notes Mariann Padkaer, coordinator of the EU-funded WindTRRo project. Leading-edge erosion is a major cause of wind turbine blade wear. Blade exposure to airborne particulates, sand, raindrops and ice could cause small cracks in the leading edge, thereby ruining the coating and decreasing aerodynamic efficiency. The impact of these solid and liquid particles might sound incredible but the blade tip could be spinning at speeds of over 200 km/h. “Eroded edges decrease the power generated and weaken the basic blade structure in the long run. Regular maintenance of wind turbine blades is crucial for operating them with optimal performance,” notes Padkaer.
A safer and lower-cost alternative
Repair works are currently carried out by specially trained rope access technicians who hang outside the wind turbine nacelle – a highly risky and expensive venture. Rope Robotics unveiled the BR-8 robot that takes over this dangerous and costly job. This robot can handle maintenance and repair of wind turbine blades reliably in a much larger weather window than traditional methods. “Repairing a turbine blade is all about rebuilding its aerodynamics,” notes Padkaer. When the robot is hoisted and properly adjusted, it documents the extent of damage and defines the repair process that needs to be followed. Software ensures the correct repair planning and execution at an optimised speed. The BR-8 switches between various tools carried on its back to perform different tasks. “The robot is conducting all repair processes needed, such as sanding, cleaning and applying a new coating on the surface. This final step is also referred to as leading-edge protection, which helps rebuild the blade shape,” adds Padkaer. Sanding is crucial for ensuring that the blade surface is rough enough so that paint adheres to it. The surface is cleaned with isopropyl alcohol to remove the remaining dust, grease and water. To further reduce the repair process time, a new leading-edge coating was developed that applies filler and paint in a single step. Every step throughout the operation is thoroughly documented.
A self-dependent robot
BR-8 robot is remotely controlled – the only manual work involved is pretty simple: attaching the ropes, connecting the robot and ‘pressing the start button’ to get the robot onto the blade and then conducting quality control of the scanned images provided. “To operate the robot without human input, we taught it how to measure the distance and the angle between itself and the turbine blade edge. Classic computer vision methods helped achieve a near-perfect distance prediction, while also eliminating the need for manual blade repositioning,” explains Padkaer. Robe Robotics significantly advanced the automation and user-friendliness of robots that conduct wind turbine maintenance. It also defined the complete operational set-up, including the safety and training procedures, integrated the ancillary equipment and tailored the marketing and communication activities to commercialise the technology. “Our BR-8 robot sets new standards for state-of-the-art wind turbine blade repair and inspection services for the entire wind turbine industry,” concludes Padkaer.
Keywords
WindTRRo, robot, repair, wind turbine blade, coating, leading-edge erosion, sanding
