Random external disturbances/parametric uncertainties and other factors deteriorate the tracking control performances of the quadrotor UAV (QUAV). To achieve fast speed and high accuracy performances for the QUAV, an adaptive fractional-order nonsingular fast terminal sliding mode (AFONFTSM) controller is proposed in this paper. Nonsingular fast terminal sliding mode surfaces with fractional derivative and integral are designed for both attitude and position of the QUAV. The proposed FO nonlinear sliding surfaces ultimately and successively allow attitude and position tracking errors to converge towards zero in a finite-time. Moreover, by designing adaptive laws based on only velocity and position variables for the AFONFTSM controller, the upper bound of uncertainties/disturbances affected the QUAV dynamics are rejected. To prove the finite time convergence and zero attitude/position tracking errors using the suggested AFONFTSMC scheme, stability analysis is proposed. Simulation results under different cases show the effectiveness of the AFONFTSMC in terms of disturbances rejection and path following performances in comparison with recently FO controller, adaptive nonsingular fast terminal SMC, and other nonlinear controllers for the QUAV.

The purpose of this paper is to solve the problem of controlling of the quadrotor exposed to external constant disturbances. The quadrotor system is partitioned into two parts: the attitude subsystem and the position subsystem. A new robust integral terminal sliding mode control law (RITSMC) is designed for stabilizing the inner loop and the quick tracking of the right desired values of the Euler angles. To estimate the disturbance displayed on the z-axis and to control the altitude position subsystem, an adaptive backstepping technique is proposed, while the horizontal position subsystem is controlled using the backstepping approach. The stability of the quadrotor subsystems is guaranteed by the Lyapunov theory. The effectiveness of the proposed methods is clearly comprehended through the obtained results of the various simulations effectuated on MATLAB/Simulink, and a comparison with another technique is presented.