This is a pretty incredible amount of tech in such small packages and the synchronizing and positioning is pretty cool too.
The primary technical inventions outlined in the report are the creation of a localization technique to let multiple drones coordinate with eachother as they inspect something, as well as the creation of a path planning algorithm to help them not only inspect the structure, but also gather enough data “to enable the generation of an off-line 3D model of the structure”.
Hardware: For this project the researchers use a MAV platform from Ascending Technologies called the ‘NEO hexacopter’, which is capable of 26 minutes of flight (without payload and in ideal conditions), running an onboard Intel NUC computer with a Core i7 chip, 8GB of RAM, with the main software made up of Ubuntu Server 16.04 running the Robotic Operating System (ROS). Each drone is equipped with a sensor suite running a Visual-Inertial sensor, a GoPro Hero4 camera, a PlayStation Eye camera, and a laser range finder called RPLIDAR.
How the software works: The Cooperative Coverage Path Planner (C-CPP) algorithm “is capable of producing a path for accomplishing a full coverage of the infrastructure, without any shape simplification, by slicing it by horizontal planes to identify branches of the infrastructure and assign specific areas to each agent”, the researchers write. The algorithm – which they implement in MATLAB – also generates “yaw references for each agent to assure a field of view, directed towards the structure surface”.
Localization: To help localize each drone the researchers install five ultra-wide band (UWB) anchors around the structure, letting the drones access a reliable local coordinate, kind of like hyper-local GPS, when trying to map the structure.
Source: Towards a future where all infrastructure is surveyed and analyzed by drones (Scroll down to that section.)