Flight dynamics modeling for a small-scale flybarless helicopter UAV

Abstract

We present a UAV helicopter flight dynamics nonlinear model for a flybarless articulated Pitch-Lag-Flap (P-L-F) main rotor with rigid blades, applicable for high bandwidth control specifications, for both ClockWise (CW) and Counter-ClockWise (CCW) main rotor rotation, and valid for a range of flight conditions including autorotation and the Vortex-Ring-State (VRS). The model includes the main rotor, tail rotor, and the fuselage. Additionally, the paper reviews all assumptions made in deriving the model, i.e. structural, aerodynamics, and dynamical simplifications. Simulation results show that the match between this model and an equivalent nonlinear FLIGHTLABR® model is very good for static (trim) conditions, is good for dynamic conditions from hover to medium speed flight, and is fair to good for dynamic conditions at high speed. Hence, this model could potentially be used to simulate and investigate the flight dynamics of a flybarless UAV helicopter, including in autorotation and VRS conditions. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.