Integral Backstepping Controller for an Autonomous Helicopter.

In this paper, we present the result of nonlinear control technique applied to an autonomous quad-rotor helicopter called X4-flyer. By using Backstepping procedure, we can stabilize the engine in hovering and generate its trajectory. Moreover, for rejecting external load disturbance, two controls are presented, PI-Backstepping which is the combination between PI and Backstepping into the so-called Integral Backstepping, and the second is Backstepping with an estimator. We studied the robustness of the used controllers in the presence of disturbances. We presented the case of the disturbances with wind influence. This allows proving the effectiveness of the proposed control law. [ABSTRACT FROM AUTHOR]