Robust Landing Control of a Quadcopter on a Slanted Surface

A robust landing control algorithm is proposed for a quadcopter, as well as for a landing platform to land on an inclined or problematic surface. To use the quadcopter for outdoor application, it is necessary to design a landing platform that can withstand environmental obstacles such as wind and weight load during landing. Conventional retractor landing platforms are not suitable for achieving a stable landing on inclined surfaces or obstacles. Therefore, in this paper, 2-link structured landing legs are applied to stably land on an inclined surface or obstacle with a suitable control algorithm. To achieve stable landing on a slanted surface, a cooperative control algorithm of the quadcopter and the landing platform has been proposed. The proposed robust landing system comprises two controllers, i.e., a high-speed proportional derivative control for the landing platform and a neural network-based proportional–integral–derivative control for controlling the quadcopter in real time. A quadcopter with a robust landing platform has been implemented, and the performance of the robust landing control algorithm has been demonstrated with the system.