简介:Robust tracking controller design is a key technology for unmanned UAV to achieve the flying target. Based on bi-limit homogeneity property, this paper researches the fixed time trajectory tracking controller design for quadrotor UAV under environmental disturbances. By the design of a multivariable fixed time disturbance observer, the continuous homogenous position and attitude tracking controllers are proposed and fixed time convergence is ensured. A comprehensive rigorous stability proof is presented with the combination of bi-limit homogeneity and Lyapunov technique. Finally, the designed controllers are utilized to track a pre-planned trajectory in the 3D space and simulation results illustrate the effectiveness.