Incremental Nonlinear Dynamic Inversion for a Dual-Ducted-Fan UAV Attitude Control under In-Ground-Effect

This paper is aimed at modeling and attitude control of a dual-ducted-fan UAV under in-ground-effect(IGE). As the UAV flies and hovers over ground or above obstacles, the IGE can cause changes in thrust/torque that drastically affects flight behavior, especially during takeoff/landing. To address this problem, the paper derives a six degree-of-freedom model of the aircraft dynamics firstly. Then, key parameters and in-ground-effect features are obtained through measurements. In order to achieve stable attitude tracking control with in-ground-effect adapting, an incremental nonlinear dynamic inversion(INDI) based cascade controller is designed. Finally, the performance of the designed INDI controller is verified by stability proof, simulations and real flight experiments.