Application of the Improved Incremental Nonlinear Dynamic Inversion in Fixed-Wing UAV Flight Tests

Abstract

Incremental nonlinear dynamic inversion shows good robustness and low dependence on the model information. In this study, incremental nonlinear dynamic inversion is improved and utilized to solve the six-degrees-of-freedom waypoint tracking problem of fixed-wing unmanned aerial vehicles (UAVs). This research is focused on studying the acquisition of the state derivatives and the processing method of the derivative time delay. A nondelay differentiator design method and an incremental gain method that responds to time delay are developed in this study. Additionally, a universal waypoint navigation method based on incremental nonlinear dynamic inversion is put forward to enable the aircraft to successfully reach its waypoint from any spatial position and under any motion states. Finally, the proposed improvements of the incremental nonlinear dynamic inversion are verified through flight tests.