Adaptive Fractional-Order Nonsingular Fast Terminal Sliding Mode Based Robust Tracking Control of Quadrotor UAV With Gaussian Random Disturbances and Uncertainties

Random external disturbances/parametric uncertainties and other factors deteriorate the tracking control performances of the quadrotor unmanned aerial vehicle (QUAV). To achieve fast speed and high accuracy performances for the QUAV, an adaptive fractional-order nonsingular fast terminal sliding mode controller (AFONFTSMC) is proposed in this article. Nonsingular fast terminal sliding mode surfaces with fractional derivative and integral are designed for both attitude and position of the QUAV. The proposed fractional-order (FO) nonlinear sliding surfaces ultimately and successively allow attitude and position tracking errors to converge toward zero in a finite time. Moreover, by designing adaptive laws based on only velocity and position variables for the AFONFTSMC, the upper bound of uncertainties/disturbances that 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.