Non-Singular Terminal Sliding Mode Tracking Control of a Quadrotor with External Disturbances

In this paper, fast and accurate trajectory tracking control of a quadrotor with complex unknowns including unmodeled dynamics, uncertainties and unknown disturbances is addressed within a proposed non-singular terminal sliding mode (NTSM) control framework. Main contributions are as follows: 1) A nominal NTSM control framework is established to achieve exact trajectory tracking control of a quadrotor, whereby finite-time stability is ensured by combining Lyapunov approach; 2) Within the NTSM control scheme, a finite-time disturbance observer is further nested to rapidly and accurately reject complex disturbances, and thereby contributing to a novel NTSM control scheme based on finite-time disturbance observer which can realize exactness of trajectory tracking and disturbance observation; 3) The finite-time stability of the closed-loop tracking system can be guaranteed rigorously via Lyapunov approach. Finally, simulation results demonstrate the effectiveness of the proposed NTSM control scheme.