Trajectory tracking anti-disturbance control for unmanned aerial helicopter based on disturbance characterization index

This work studies the trajectory tracking control for unmanned aerial helicopter (UAH) system under both matched disturbance and mismatched ones. Initially, to tackle the strong coupling, an input-output feedback linearization method is utilized to simplify the nonlinear UAH system. Secondly, a set of finite-time disturbance observers (FTDOs) are proposed to estimate mismatched disturbances with their successive derivatives, which are utilized to design the feedforward controller via backstepping. Thirdly, as for matched disturbance, by defining the disturbance characterization index (DCI) to determine whether the disturbance is harmful or not for the UAH system, a feedback controller is proposed and a sufficient condition is established to ensure the convergence of the tracking error. Finally, some numerical simulations and comparisons illustrate the validity and advantages of our control scheme.