Global Fast Terminal Sliding Mode Control Law Design of a Quadrotor

The conventional sliding mode control cannot converge to zero in finite time, and it has a feeble robustness because of its linear sliding mode surface with uncertain variable disturbances, in order to solve these problems, this paper presents an adaptive global fast terminal sliding mode control (GFTSMC) based on a quadrotor UAV. Firstly, the mathematical model of quadrotor is given via Euler-Lagrange method. A double closed-loop structure is designed, the GFTSMC laws are formulated in the outer loop controller to track the position signal, and to track the attitude signal in the inner loop controller. To eliminate the chattering, the sign function is replaced by a saturation function. The stability of system is proved by Lyapunov method. Finally, the demonstrative simulation results are shown to embody the superiorities of GFTSMC compared with the classical sliding mode control (CSMC).