ABSTRACT:In order to improve the slow convergence speed and low tracking accuracy of the traditional discrete Sliding mode control algorithm (D-SMC) in attitude control and position tracking of quadrotor UAV, a discrete Sliding mode control algorithm (D-FOSMC) based on fractional order calculus theory has been proposed. The algorithm combines the definition of Grunwald Letnikov fractional calculus with the traditional discrete Sliding mode control, proves the stability of the designed control algorithm by using Lyapunov function, and verifies the effectiveness of the proposed algorithm through UAV fixed point flight and hover flight simulation. The simulation results show that the proposed algorithm has certain advantages in improving convergence speed and control accuracy compared to traditional discrete sliding mode algorithms.