Here’s a story about a tiny little bit of technology that could have a significant impact on renewable energy, particularly wind turbines. Efficiency is a big deal in the world of wind and solar energy. Dust, dirt, pollen and bird droppings can reduce the efficiency of solar panels, so people have invented ways to wash them in order to keep them producing electricity as efficiently as possible. Wind turbines have blades that can be hundreds of feet long and weigh thousands of pounds. Not only do they operate high up in the air, many are located miles offshore where accessing them is both difficult and hazardous.
Turbine blades need to be inspected regularly to spot potential structural weaknesses or damage that may affect their efficiency. Any surface defects can create unwanted turbulence which in turn lowers the amount of electricity produced for a given amount of wind. Necessity is the mother of invention, so they say. From his work as a turbine blade designer, Chris Cieslak came up with the idea of automating the inspection and maintenance process that is vital to keep wind turbines producing at peak efficiency.
“One of the main issues, especially offshore, is leading edge erosion,” Cieslak tells the American Society of Mechanical Engineers. “The last 20 percent of the blade gets eroded by rain or grit and blasted to a rough surface. That can lead to a loss of aerodynamic performance and if left to get worse, premature structural failures.” Traditionally, the only way to inspect turbine blades was to conduct a visual inspection by people hanging from ropes attached to the top of a turbine pylon. Cieslak had a better idea, a six legged robot he calls BladeBUG which “walks” along a turbine blade from one end to the other, using suction cups to keep it from falling off.
The final product is much different from the original design, which was a wheel fitted with vacuum cups around its circumference that looked like a miniature Ferris Wheel. That design morphed into a tracked vehicle that used a vacuum to keep it from falling off. The six legged robot was designed with the shape of a turbine blade in mind. The blades are round where they connect to the rotor and flatten out farther down the length of the blade. “We needed something with dexterity. A multi-legged robot solved the problem of navigating over a changing surface,” Cieslak says.
BladeBUG passed its first big test recently, walking up and down a 50 meter long turbine blade on a 7 MW demonstration turbine operated by Offshore Renewable Energy Catapult, a UK group that works with private developers and industry to test innovative technologies and help bring them to market. The robot is operated remotely by a technician as it conducts visual inspections and nondestructive testing. It is also capable of making some repairs during its journey. “The BladeBUG concept recognizes that there is a safer, more cost effective and efficient way of working,” says Chris Hill, operational performance director at ORE Catapult.
ORE Catapult says BladeBUG may be able to lower maintenance and repair cost by between 30 and 50 percent because it can operate in weather conditions that are impossible for the people who have to rappel down the blades to carry out inspections. “Techs spend half their time unable to perform their job,” Cieslak notes. “The robot is designed to be really user friendly, so you can use regular technicians who might need to be upskilled to perform the tasks that now need a specialist crew.”
The next step for the BladeBUG is to repeat the inspection walk on lightening protection gear, followed by further trials with wind turbine operators interested in seeing how the robot performs on their own turbines. Commercial viability is expected by the end of 2021. “We see the future as being a lot more automated, especially offshore. Having this vision of autonomous vessels and drones is how we see improvements coming,” Cieslak says.
Financial support for BladeBUG is part of MIMREE, the Multi-Platform Inspection, Maintenance, And Repair In Extreme Environments initiative that is part of Innovate UK. It is bringing together experts in robotics, nondestructive testing, artificial intelligence, space mission planning, marine and aerial engineering, and nanobiotechnology to show how offshore wind and maintenance work can be conducted using autonomous vessels, aerial vehicles, and crawler robots.
To see the BladeBUG in action, check out the video below.