Flexible Aircraft Gust Load Alleviation with Incremental Nonlinear Dynamic Inversion

In this paper, an Incremental Nonlinear Dynamic Inversion (INDI) controller is developed for the flexible aircraft gust load alleviation (GLA) problem. First, a flexible aircraft model captures both inertia and aerodynamic coupling effects between flight dynamics and structural vibration dynamics is presented. Then an INDI GLA controller is designed for this aircraft model based on sensor measurements and the Kalman filter online estimation. Besides, the fifth order Pade approximation is used to model the pure time delay in the state estimation. Furthermore, simulations of the flexible aircraft flying through various spatial turbulence and gust fields demonstrate the effectiveness of the proposed controller on rigid-body motion regulation, vertical load alleviation, wing root bending moment reduction and elastic modes suppression. Additionally, numerical perturbation tests and a Monte-Carlo study show the robustness of the proposed controller to aerodynamic model uncertainties.