Quadrotor Trajectory Tracking Control against Uncertainties for Autonomous Landing Task

The trajectory tracking control problem of quadrotor unmanned aerial vehicles has attracted great attention from researchers all around the world in recent years. Nevertheless, designing superior controllers for a quadrotor is still a challenge as model uncertainties, and external disturbances always exist and induce significant degradation in the control performance. In this paper, we propose two control laws to solve the quadrotor trajectory tracking and landing control problem under the presence of both uncertainties and external disturbances. Based on the backstepping control technique, the quadrotor attitude and the horizontal position controllers are devised to deal with the additive disturbances. In addition, the vertical position is controlled by a time-delay controller with switching action to address both additive and multiplicative uncertainties such as the system's mass-varying problem or the ground effect. Numerical simulation results demonstrate the effectiveness of the proposed algorithm.