X-hale autopilot with stability augmentation and shape control based on loop separation

Abstract

© 2017 International Forum on Aeroelasticity and Structural Dynamics (IFASD). All rights reserved.Highly-flexible aircrafts present high-aspect-ratio wings that introduce nonlinearities into the flight dynamics and make more complex models and control methods necessary. In this paper, a loop separation concept is applied to the X-HALE aircraft, giving rise to a control system comprising an inner-loop capable of controlling the shape of the aircraft while keeping the plant stable, and an outer-loop capable of controlling velocity, altitude, bank angle and sideslip angle. The outer-loop has a decoupled structure for longitudinal and for the lateral-directional axes. The matrices of the compensators were obtained using non-smooth optimization. Gain-scheduling techniques are implemented to bypass stability problems arising from changes in the plant with flight speed. Nonlinear simulations show promising results for implementation on the real aircraft.

Keywords