Fixed-Time Controller Design for a Quadrotor UAV with Asymmetric Output Error Constraints

In this article, a fixed-time tracking control strategy is proposed for a quadrotor UAV (QUAV) with external disturbance and asymmetric output error constraints. Firstly, a dynamic model of the QUAV is transformed into a strict feedback system with external disturbance, and it is decoupled into attitude subsystem and position subsystem for simplifying controller design. Secondly, an asymmetric tangent barrier Lyapunov function (ATBLF) is applied to solve the tracking error constraints problem, and a fixed-time control law is designed. Meanwhile, a fixed-time disturbance observer (FTDO) is designed to cope with external disturbance. Then, it is proved that the designed controller guarantees the tracking error remains within the constraint ranges and converges to zero in fixed-time by Lyapunov stability theory. Finally, the effectiveness of the proposed control scheme is verified by numerical simulations.