Robust Trajectory Control for Quadrotors with Disturbance Observer

In this paper, the problem of trajectory tracking is researched and an effective control scheme based on disturbance observers (DOB) is presented for quadrotors to deal with the influences caused by time-varying mass, inertia and other uncertainties. The control scheme proposed here includes an inner attitude control loop and an outer position control loop. Both control loops include a DOB and a nominal nonlinear controller. The DOB is introduced to compensate the influences of uncertainties such as model mismatches, external disturbances and sensor noises in the rotational and translational dynamics. Then a nominal nonlinear controller is applied to the compensated model to achieve the desired tracking performance. A simulation verifies the robustness and effectiveness of the proposed scheme in the presence of various uncertainties.