Adaptive Sliding Mode Control with an Extended Disturbance Observer for a Quadcopter Unmanned Aerial Vehicle: A Finite-Time Convergent Approach

Robust flight control always plays an important role in the accurate tracking of the desired path by the quadcopter vehicle. The hybrid strategy used for this purpose proved quite effective in enhancing the overall efficiency of flight control. This research study presents a robust nonlinear control scheme for a quadcopter vehicle experiencing unknown internal and external disturbances while performing its routine tasks. An extended disturbance observer (EDO) is used to estimate the real-time disturbance variables acting on the quadcopter vehicle which is then shared with the non-singular fast terminal sliding mode control (NSFTSMC), eventually, the control is robust and adaptive. The Lyapunov stability theory is applied to assess the stability of the designed closed-loop control and through several simulation analyses, it is confirmed that the proposed scheme is capable of converging the states of the vehicle to the desired states in finite time despite various disturbances.