Time-Domain System Identification and Validation of Small Fixed-Wing UAV Dynamics

Abstract

This paper presents time domain identification and validation of the aerodynamic model of the Skywalker X8 unmanned aerial vehicle (UAV). Previous modeling efforts include static coefficients derived from wind tunnel experiments and a model based on body velocity coefficients. Our study builds on these results, introducing a new model that adheres to the classical aerodynamic structure identified through stepwise regression. Our paper combines propulsion system modeling results based on wind tunnel tests with data from flight experiments to identify the airframe aerodynamics of the Skywalker X8 UAV. To validate the model, we present model predictions for 10-second long maneuvers, performed at the cruise speed of 18 m/s, including force and moment coefficients (C_D, C_Y, C_L, C_l, C_m, C_n). In summary, this paper introduces a novel simulation-ready aerodynamic model for the Skywalker X8 UAV, identified in the stability frame, allowing a direct comparison with a larger set of UAV models and CFD results available in the literature, often presented in terms of lift and drag analysis.