Composite global non‐singular fast terminal sliding mode trajectory tracking sensorless control of quadrotor UAV with uncertain disturbances

This article proposes a composite global non‐singular fast terminal sliding mode trajectory tracking problem for quadrotor UAVs affected by multi‐source uncertain disturbances. Firstly, the quadrotor UAV modeling is modularly defined, and the trajectory tracking problem will be transformed into the stabilization of the tracking errors by fully considering the dynamic characteristics of its position and attitude loops. Secondly, the lumped disturbances containing coupling and external disturbance terms in each channel and the rate of change of tracking error are estimated via an extended state observer. Then, based on estimated information and non‐singular fast terminal sliding mode, a composite global non‐singular fast terminal sliding mode is constructed in the position and attitude loops, respectively. To ensure the continuity of control quantity, the controller design introduces a saturation function instead of the sign function. The stability of the system is proved by using the Lyapunov function. Finally, the actual control quantity of the quadrotor UAVs, the rotor speed, is calculated based on the control quantity in the position and attitude loops. The effectiveness of the proposed method will be verified based on real quadrotor UAV data.