Fractional-Order Fast Terminal Sliding Mode Control for Quadrotor UAV Under Actuator Saturation

In this study, a delicate fractional-order fast terminal sliding mode controller is proposed for the position and attitude tracking of a quadrotor UAV under actuator saturation. In this controller, the fractional order calculus is incorporated to the fast terminal sliding mode surface design, which can enhance the convergence speed of the controlled UAV system. Meanwhile, to solve the problem of actual control input limitation, a RBF-based estimator is designed to evaluate the error between the virtual control input and actual control output. The stability of the controlled system is proved by using Lyapunov theorem, where the validity and effectiveness of the proposed controllers and estimator are verified by a detailed numerical simulation.