Robots Step Up to the Dirty Work for NREL’s Turbine Manufacturing

Part of the growth in the use of robots is due to the flexibility of the machines themselves. In the past, robots were deployed mostly for repetitive tasks such as automotive painting and welding. As robots become increasingly handy with complex tasks, their use increases. A recent example is the deployment of robots in wind turbine production at a US Department of Energy’s National Renewable Energy Laboratory (NREL) lab. Researchers at NREL have successfully leveraged robotic assistance in the manufacture of wind turbine blades, allowing for the elimination of difficult working conditions for humans and the potential to improve the consistency of the product.

Although robots have been used by the wind energy industry to paint and polish blades, automation has not been widely adopted. Research at the laboratory demonstrates the ability of a robot to trim, grind, and sand blades. Those necessary steps occur after the two sides of the blade are made using a mold and then bonded together.

NREL Engineers Offer Details in a Paper

Hunter Huth, a robotics engineer at NREL detailed the use of robots in blade manufacturing in a recent paper. “I would consider it a success,” said Huth. “Not everything operated as well as we wanted it to, but we learned all the lessons we think we need to make it meet or exceed our expectations.”

The paper, “Toolpath Generation for Automated Wind Turbine Blade Finishing Operations,” appears in the journal Wind Energy. The coauthors, all from NREL, are Casey Nichols, Scott Lambert, Petr Sindler, Derek Berry, David Barnes, Ryan Beach, and David Snowberg.

Let Robots Do the Dirty and Dangerous Work

The post-molding operations to manufacture wind turbine blades require workers to perch on scaffolding and wear protective suits including respiratory gear. Automation, the researchers noted, will boost employee safety and well-being and help manufacturers retain skilled labor.

“This work is critical to enable significant US-based blade manufacturing for the domestic wind turbine market,” said Daniel Laird, director of the National Wind Technology Center at NREL. “Though it may not be obvious, automating some of the labor in blade manufacture can lead to more US jobs because it improves the economics of domestic blades versus imported blades.”

Part of the effort to deploy robotics is to help reduce costs and make US manufacturing competitive worldwide. “The motive of this research was to develop automation methods that could be used to make domestically manufactured blades cost competitive globally,” said Huth. “Currently offshore blades are not produced in the U.S. due to high labor rates. The finishing process is very labor intensive and has a high job-turnover rate due to the harsh nature of the work. By automating the finishing process, domestic offshore blade manufacturing can become more economically viable.”

The research was conducted at the Composites Manufacturing Education and Technology (CoMET) facility at NREL’s Flatirons Campus. The robot worked on a 5-meter-long blade segment. Wind turbine blades are considerably longer, but because they bend and deflect under their own weight, a robot would have to be programmed to work on the bigger blades section by section.

The researchers used a series of scans to create a 3D representation of the position of the blade and to identify precisely the front and rear sections of the airfoil—a special shape of the blade that helps the air flow smoothly over the blade. From there, the team programmed the robot to perform a series of tasks, after which it was judged on accuracy and speed. The researchers found areas for improvement, particularly when it came to grinding. The robot ground down too much in some parts of the blade and not enough in others.

“As we've gone through this research, we've been moving the goal posts for what this system needs to do to be effective,” Huth said. He noted that an automated system would provide consistency in blade manufacturing that is not possible when humans are doing all the work. He also said a robot would be able to use “tougher, more aggressive abrasives” than a human could tolerate.