Nonlinear robust control of a quadrotor for point tracking based on nonlinear disturbance observer

In this paper, a nonlinear robust control problem is addressed for point tracking of quadrotor. The nonlinear robust controller is designed based on nonlinear disturbance observer which estimates external disturbances of quadrotor. Proposed controller can be divided into two parts which are nonlinear controller and robust controller. Basically, the nonlinear controller is designed to track the desired point and the robust controller is added to compensate external disturbances which estimated by the designed nonlinear disturbance observer. Simulation results show the performance of the designed nonlinear robust controller and disturbance observer.