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International Journal of Aerospace Engineering
Volume 2013 (2013), Article ID 289357, 25 pages
http://dx.doi.org/10.1155/2013/289357
Research Article

Adaptive and Resilient Flight Control System for a Small Unmanned Aerial System

Department of Aerospace Engineering, University of Kansas, 2120 Learned Hall 1530 W 15th Street, Lawrence, KS 66045, USA

Received 2 October 2012; Revised 18 February 2013; Accepted 18 February 2013

Academic Editor: Nicolas Avdelidis

Copyright © 2013 Gonzalo Garcia and Shahriar Keshmiri. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The main purpose of this paper is to develop an onboard adaptive and robust flight control system that improves control, stability, and survivability of a small unmanned aerial system in off-nominal or out-of-envelope conditions. The aerodynamics of aircraft associated with hazardous and adverse onboard conditions is inherently nonlinear and unsteady. The presented flight control system improves functionalities required to adapt the flight control in the presence of aircraft model uncertainties. The fault tolerant inner loop is enhanced by an adaptive real-time artificial neural network parameter identification to monitor important changes in the aircraft’s dynamics due to nonlinear and unsteady aerodynamics. The real-time artificial neural network parameter identification is done using the sliding mode learning concept and a modified version of the self-adaptive Levenberg algorithm. Numerically estimated stability and control derivatives are obtained by delta-based methods. New nonlinear guidance logic, stable in Lyapunov sense, is developed to guide the aircraft. The designed flight control system has better performance compared to a commercial off-the-shelf autopilot system in guiding and controlling an unmanned air system during a trajectory following.