Fuzzy integral backstepping control approach in attitude stabilization of a quadrotor UAV

In this paper we present a hybrid control method for a vertical flight four-rotor helicopter, named quadrotor. Quadrotor helicopter is a nonlinear dynamical system which is inherently unstable, thus the stabilization and hovering is critically challenging. Conventional control approaches use linear control theory that is suitable for linear systems only. In this approach, first we derive a nonlinear dynamic model of quadrotor, and then we performed a mixed controller using classical and intelligent control methods for stabilizing rotational dynamics. Integral Backstepping (IBS) is a reinforced nonlinear widely used control law, for such a system, but finding the appropriate coefficient of this algorithm is a critical job. The problem has been solved with fuzzy control method. Fuzzy as an intelligent control method is a powerful technique and has been presented to realize robust attitude control for a quadrotor. This study showed that although, both of the classical IBS and the Fuzzy IBS controllers can control the system properly, the Fuzzy IBS controllers performed slightly better than the classical IBS controllers, and have benefits such as better disturbance rejection and more robustness.