Unsteady Non-linear Control Surface Modelling for Aeroservoelastic Applications

In this paper, we present a data-driven method to model the unsteady non-linear response of aircraft control surfaces. This method relies on aerodynamic reduced-order models (ROM) derived from computational fluid dynamics with Reynolds averaged Navier-Stokes (CFD-RANS) analysis in the transonic domain. The ROM consists of a combination of look-up tables and transfer functions, with which we can capture the incremental unsteady loads from aileron and spoiler large deflections. The ROM can replicate transient CFD results with a 5% margin of error in most scenarios using a realistic 3D wing model. We also investigate a hybrid approach to calculate aeroelastic wing deformations. To do so, we simulate the control loads with our the aforementioned ROM, while we rely on a fast but robust low-fidelity method to model the wing aeroelastic response. We compared this method against high-fidelity analysis and estimated an average error of 5% to 10% in most of the cases with a three orders of magnitude decrease in simulation time. The rapidity of such load estimation technique makes it suitable for wing sizing and flight control optimisation problems.