A Nonlinear Digital Robust Controller for UAV

Abstract

Flying vehicles in their trajectories are under various uncertainties. Due to some reasons such as variation of aerodynamic coefficients, limited information of system and unwanted noise in system, the flying vehicle has a complicated system including uncertainties. In this paper the research RPV under studying have a coupled dynamics. In existing PID controllers this coupling is not considered. By considering all model uncertainties, noises, model deviations, and unknown input signals in controller design, the system response will be robust. The RPV dynamic generally is nonlinear and coupled which is linearized in design points. Using H <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">alpha</sup> and mu synthesis methods two robust controllers are designed such satisfy both stability and robust performance. Also by using Tustin transform, we design digital robust controller for our data-sampled system. The responses of H <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">alpha</sup> controller are compared with the responses of nonlinear and coupled simulation of RPV.