L2-gain robust trajectory tracking control for quadrotor UAV with unknown disturbance

In this paper, the trajectory tracking problem of the position and yaw angle of an underactuated quadrotor UAV is studied. Considering that the quadrotor UAV often encounters unknown disturbance resulted by model parameter perturbations and environmental changes, a new L-2-gain robust control method is presented based on dissipation theory. First, the dynamic model of the quadrotor UAV with disturbances is transformed by introducing three virtual control variables. In this way, the trajectory tracking control can be implemented by the dual loop control, that is, the position control loop and the attitude control loop. Then, based on dissipation inequality, the robust position controller and attitude controller are developed to guarantee the L-2-gain of the system to the unknown disturbance. It is proved that all the tracking errors are uniformly ultimate boundedness. In addition, the controller is further reconstructed by introducing a new class K functions to improve the transient and steady-state performances of the quadrotor UAV system. In the end, two simulation examples are provided to check the validity of the control method proposed and the convergence of the quadrotor UAV trajectory tracking error.