Industrial wind turbine towers can reach as high as over 400 feet, making inspection of turbine blades hazardous for human operators. Thanks to machine vision and the utility of UAVs, these risks can be eliminated completely.
SkySpecs, headquartered in Ann Arbor, MI, USA and Amsterdam, Netherlands, offers fully-automated drone inspections of wind turbines. According to SkySpecs one of its drones, based on the Freefly Alta drone platform, can complete an inspection in 15 minutes or less, detecting the location of cracks or erosion on individual blades by scanning each blade from meters above its surface.
Once activated the drone takes off, locates the wind turbine, flies to the top of the tower and identifies the blade locations. The drone then plans the most efficient route to complete its inspection using a combination of sensors that includes LiDAR scanning. These are not pre-programmed routines based on turbine make and model, according to SkySpecs. The style and manufacturer of the turbine are irrelevant.
The company does not provide camera specs for its drones, however says that a 2 mm wide crack would be detected during the inspection. Low light conditions are accounted for by the camera's proximity to the blade being inspected and by adjusting the settings for each picture taken. Images are set to overlap in order to make sure every surface is fully inspected and each image is correlated with laser and GPS information to ensure the accuracy of damage size and relative position data. The precise location on the blade of each image is also tagged to allow for comparing images after future inspections.
The inspection results are not automated. They require analysis by experts, and customers can view inspection data and reports through SkySpec's Web portal. However, Skyspecs is currently working on automatic analysis algorithms. In the future, the company plans to offer inspection routines other than for wind turbines.