Fractional-order nonsingular terminal sliding mode controller for a quadrotor with disturbances

This paper proposes a finite-time controller for an unmanned aerial vehicle in the presence of Figures/uncertainties using fractional-order terminal sliding mode. First, contrary to existing fractional-order backstepping sliding mode controllers, this paper introduces a new control approach for quadrotor position control, which is based on fractional-order fast terminal backstepping sliding mode control. Using an appropriate sliding surface, the position tracking error converges to zero in finite time while providing good robustness properties in different complex path scenarios under unknown disturbances. Then, a novel fractional-order fast terminal sliding mode control scheme is developed for quadrotor attitude control, which provides good properties in terms of robustness against unknown disturbances, and in terms of convergence time, etc. Finally, simulation results are presented to discuss the advantages of the hybrid control approach proposed in this work for quadrotors under unknown disturbances compared to other existing controllers