Adaptative Friction Shock Absorbers and Reverse Thrust for Fast Multirotor Landing on Inclined Surfaces

Small multirotors are not capable of landing in complex situations, such as on inclined surfaces, in wind gusts or at high impact velocities. This paper explores the use of lightweight friction shock absorbers, combined with rapid thrust reversal, to increase the landing envelope of a quadrotor. The friction shock absorbers serve to dissipate the drone’s kinetic energy and the reverse thrust increases the maximum slope inclination at which it can land. A landing gear prototype was designed and implemented on a DJI F450, and a model was created to generate landing maps to evaluate its benefits. Finally, the technology was tested in real outdoor conditions. The overall system enables drones to safely land on surfaces of up to 60° and at vertical speeds of up to 2.75 m/s, thus increasing the landing envelope by a factor of 8, compared to traditional multirotors.