Fixed-Time Disturbance Rejection Control Scheme for Quadrotor Trajectory Tracking

This article proposes a fixed-time disturbance rejection control strategy for quadrotor trajectory tracking with unknown disturbances. The fixed-time extended state observer (FxESO) is introduced to estimate the internal uncertainties and external disturbances. Unlike most of the disturbance rejection control strategies, the proposed FxESO theoretically guarantees that the estimation errors converge in a fixed time which is independent of the system initial condition. Inspired by proportional-derivative (PD) control and sliding mode control, a fixed-time disturbance rejection controller (FxDRC) is designed to compensate for unknown disturbances and ensure the safety flight of the quadrotor. In addition, rigorous mathematical analysis demonstrates that the quadrotor system with disturbances can achieve stability within a strict time bound, theoretically exhibiting the superiority of the proposed fixed-time control method. Finally, a series of comparative simulations and experiments validate the accurate tracking performance and robustness of the proposed approach.