Operators and inspectors have traditionally gained access to massive wind towers and their huge blades by using cranes, bucket trucks, rappelling teams, or by inspecting blades with high-power telescopes. Two different remote-controlled climbing robots have been developed to make wind tower maintenance easier, cheaper, and safer.
Helical Robotics recently demonstrated its latest model, the magnetic HR 1000-LL (Light Lift) climbing robot, at the American Wind Energy Assn. 2012 Conference and Exposition in Atlanta. (See the robot in action below.) This model hauls 50 pounds to 100 pounds of video cameras, nondestructive testing equipment, robotic arms, and lifts all the way up a wind tower's shaft and can be controlled by a single operator.
GE Global Research has been conducting tests with International Climbing Machines' tower-climbing robots, which use vacuum force to adhere to wind towers. (Source: International Climbing Machines)
The Helical Robotics' design is built to work on ferrous surfaces using the company's magnetic adhesion system. The robot's wheels are driven by electric motors that propel it up, down, and around the tower. Different models can carry payloads ranging from lightweight cameras to heavy industrial equipment.
The latest model, HR 1000-LL, self-aligns to a work surface, and is adjustable to between 0.030 inch and 0.25 inch from that surface. It measures 57 inch x 22 inch x 20 inch high, and weighs a total of 90 pounds to 145 pounds, depending on configuration. The robot gives wind tower operators and inspectors a real-time view of tower maintenance tasks from its onboard cameras. HD video can also be transmitted live to offsite personnel in a ground station using a custom-designed wireless bridge network.
Meanwhile, GE Global Research has been conducting tests with tower-climbing robots made by International Climbing Machines (ICM) on GE's wind turbines at a Texas wind farm. ICM's climbers are held to a surface with vacuum force. The robot platform consists of a vacuum chamber surrounded with a rolling locomotive seal, which lets them climb over uneven surfaces, surface contours, and surface obstacles.
The ICM robot is made of carbon fiber and advanced composites. Each weighs about 30 pounds and has a pull-off strength of more than 225 pounds. It measures 24 inch x 24 inch x 8 inch high, and travels at 2.5 inch to 3 inch per second. The robots have been used for inspecting and cleaning surfaces, spraying on coatings, and testing coatings for their integrity, as well as nondestructive testing and evaluation inspection. They can carry wireless HD video equipment to give operators on the ground a real-time view of the wind tower's blades from about 30 feet away. (Watch videos showing demonstrations of this robot here and here.)
For a better view of the blades, GE is developing a microwave scanner that the climbing robotic vehicle could carry. Microwave inspection would also let operators analyze the blade material's composition and integrity for early indications of possible breakdowns in the structure.
HelicalRobots, thanks for diving in and answering readers' questions. Beth's window washing question brings up one I had: what is the theoretical height limit, meaning, what is the power source and how far can they travel on it (or what's the half-height limit, since they have to get down again)?
Ann, thank you for taking the time to report on our technologies. Our goal is to make infrastructure more efficient by reducing cost and increasing safety thru the use of robotic solutions. Innovation only happens with adoption and that takes awareness. Early reports mean a lot to us and I personally want to say thank you.
Bruce A. Schlee
Jack, although there has been talk of other tower types, the wind industry has 100's of thousands of towers that are steel. The current size of this market as well as the vast number of tasks that robots like these can do more than creates a viable market, not to mention all the other industry applications. If needed however, we have designs for non-magnetic structures as well.
FYI. From the turbine towers I have seen, routine access is using a ladder inside the tower - a long, long climb. Workers can climb that and walk around inside the nacelle to work on the gearbox, atlernator, etc. If they need to go outside, they abseil down on ropes. The robot is still cool.
Pole-climbing robots like those from ICM have already been used for several such tasks, climbing telephone poles and other utility poles. Helical Robots says in a press release that it is working on different platforms for its climbing robots "in the conventional energy space, shipping, and steel structure areas."
Greg, I think the locomotive seal that they mention in the article "might" be sufficient to compensate for your concerns of dirt and moisture. it would have been useful if they have mentioned a little more about it, since the vertical climbing is the key to this particular robot. I was more concerned about the magnet version. I wonder how long the industry is going be using ferrous towers / poles and if this technology might be limiting the application.
Very interesting article which shows how a new energy technology can also spawn peripheral advances in other technologies areas. I would be interested to see how the different holding technologies perform in the field over time. I'm wondering how the vacuum technology will perform on a dirty/wet/moldy surface in unfavorable weather conditions.
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