Nonlinear Disturbance Observer-based Sliding Backstepping Hovering Control of a Quadrotor

In this paper, the nonlinear observer based hovering control is addressed for a quadrotor with system uncertainties and external disturbances. Main contributions are as follows: 1) A nonlinear observer for complex unknowns including unmodelled dynamics and external disturbances is designed for a quadrotor, and thereby contributing to more robustness pertaining to the closed-loop system; 2) The sliding backstepping based technique is then employed to realize hovering control of a quadrotor, and thereby leading to the proposed controller which achieves satisfactory control performance; 3) Exhaustive analyses ensure that tracking errors of the overall system can converge to a small neighborhood of the origin. Furthermore, a large number of simulation experiments show the effectiveness of the proposed control law.