Prescribed-Time Attitude and Altitude Stabilization of Hexarotor UAV with External Disturbances

This paper addresses the prescribed-time attitude and altitude stabilization problem of hexarotor unmanned aerial vehicles (UAVs) with external disturbances and model uncertainty. A novel sliding surface based on prescribed-time convergence is introduced for the proposed controller. The presented controller ensures the convergence of the hexarotor states to the origin in the prescribed time. The controller design is independent of the initial state parameters and free from singularity. Furthermore, a fixed-time disturbance observer is implemented with the control law to enhance the performance of the control design. The stability of the presented prescribed-time sliding mode control is analyzed using the Lyapunov theorem. Finally, the efficacy of the proposed controller is demonstrated using numerical simulations compared to the existing finite and fixed-time controller design.