Video: Maintenance Robots Climb Wind Towers

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.

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.

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