As the unmanned aerial vehicle (UAV) industry continues to rapidly evolve, technology challenges are being flushed out in many new areas. An interest that is growing quickly is using drones for internal infrastructure inspections. But most of these areas are confined-space, GPS-denied environments such as aboveground storage tanks (ASTs). Most "off-the-shelf " drones found in consumer electronic stores are developed with solely the outdoors in mind, making the vast majority of them poor choices to use inside such critical infrastructure. These conventional drones rely on a strong GPS signal and a compass for successful navigation outside. These features give an outdoor drone vital navigation and heading information; however, both systems are unreliable (and at times inoperative) inside thick steel and concrete environments.
So, what specifically needed to change? It meant completely redesigning a new fundamental way for a drone to navigate without GPS or a compass, making it specific to indoor flight. This new type of vehicle relies on light detection and ranging (LIDAR) as its primary navigation source. This allows the drone to fly in fully dark environments, which is often the case inside tanks during the inspection process. The LIDAR makes six full 360-degree rotations each second, collecting hundreds of points for the vehicle to learn its entire surroundings and taking the place of the GPS and compass. This also enables a laser-based collision avoidance system, meaning the operator can fly comfortably knowing the aircraft will autonomously keep a safe distance from all walls and objects. The collision avoidance feature also functions on the vertical plane.
Data-focused
Each company adding drones does so to alleviate traditional inspection methods for convenient access to better data, collected in a safer manner. For effective data, this new indoor flying system needed the capacity to look 180 degrees from ceiling to floor through a pilot-controlled knob on the transmitter. It also needed higher- quality photos than the current industry average (around 20 megapixels) to see the smallest imperfections during assessment. When initially talking to inspectors, there was a void on what to do with generic photos post-inspection. The discovery of adding a distance-capturing device on the gimbal became a huge advantage for inspectors, because this enables a live ruler feature to be used in each photo captured. With the ability to measure crack distances and corrosion surface area, API inspectors can now track issues over time, something not available with any other drone. This standardizes each inspection with numerical data rather than just pictures, proving whether asset defects are staying the same or getting worse.
API 653 inspection
But what specific parts will drones be most helpful for during AST internal inspections? API 653 sets the standard for what needs to be inspected, yet it offers flexibility for how to complete various aspects of the inspection. For instance, API 653 gives guidance for the tank roof evaluations, but it is one of the more challenging aspects of the inspection to complete. Custom internal inspection drones allow inspectors to gather roof seal and support photos very quickly without the need for building scaffolding to top portions of the AST. This will keep inspectors safely on the ground and will give them quality photos to log overtime.
For more information, contact Christian Smith at christian@interactive aerial.com, visit www.interactiveaerial.com or call (231) 715-1422.
