Onboard Safety Guarantees for Racing Drones: High-speed Geofencing with Control Barrier Functions
It provides practical safety guarantees for racing drone pilots, enabling them to push performance limits without crashing, though it is an incremental application of existing methods to a specific domain.
This paper tackles the problem of ensuring safety for racing drones at high speeds by implementing control barrier functions on lightweight hardware, achieving robust safety guarantees at speeds over 100 km/h with minimal interference to pilot inputs.
This paper details the theory and implementation behind practically ensuring safety of remotely piloted racing drones. We demonstrate robust and practical safety guarantees on a 7" racing drone at speeds exceeding 100 km/h, utilizing only online computations on a 10 gram micro-controller. To achieve this goal, we utilize the framework of control barrier functions (CBFs) which give guaranteed safety encoded as forward set invariance. To make this methodology practically applicable, we present an implicitly defined CBF which leverages backup controllers to enable gradient-free evaluations that ensure safety. The method applied to hardware results in smooth, minimally conservative alterations of the pilots' desired inputs, enabling them to push the limits of their drone without fear of crashing. Moreover, the method works in conjunction with the preexisting flight controller, resulting in unaltered flight when there are no nearby safety risks. Additional benefits include safety and stability of the drone when losing line-of-sight or in the event of radio failure.