A carbon-reinforced drone to inspect underground tunnels
French engineering group Segula Technologies has developed a prototype autonomous drone for safe inspections in complex environments.

To protect technicians exposed to high-risk environments, French engineering company Segula Technologies has developed Topone, a prototype drone designed to inspect power lines in underground tunnels and other confined spaces.
Shock-proof
The result of two years of R&D, the drone consists of a main structure resting on 4 tubes of carbon fibre reinforced polymer (CFRP), surrounded by a sheet of CFRP to protect it from knocks.
The six circular propeller protection frames are made entirely of a carbon fibre-reinforced polymer sandwich. Finally, the joints between the tubes and the top covers are made of 3D-printed plastic.
Detecting anomalies
The Topone drone is equipped with sensors and a camera providing RGB and thermographic images of the cables. The sensors measure temperature, oxygen content and levels of noxious gases to identify anomalies caused by cable breaks or cracks. The data collected is processed by an on-board computer, enabling the drone to create a 3D model of the environment to be explored and to move around the underground gallery without a constant connection to a control station.

The prototype was tested under real conditions in the galleries of the Palacio de Congresos in Malaga, Spain. The conclusive test results have paved the way for a second prototyping phase prior to future marketing in sectors such as the railways, caving and rescue, and construction and public works.