Disturbance Rejection in UAV´s velocity and attitude control: Problems and solutions

For the high nonlinearity and coupling of the model of the Unmanned Aerial Vehicles (UAVs), the control of velocity and attitude (i.e. pitch angle, roll angle, and yaw angle) under various disturbances (e.g. wind disturbances) has been a challenging research all along. In this paper, we confirm that under some simplifications the throttle-velocity subsystem is of first-order, the elevator-pitch angle subsystem, the aileron-roll angle subsystem, and the rudder-yaw angle subsystem are of second-order respectively. Then, suitable controllers are designed based on Active Disturbance Rejection Control for UAVs to maintain the velocity and attitude in various wind turbulence conditions. Simulations show that with the help of Active Disturbance Rejection Controllers, the velocity and attitude can be maintained well under various wind turbulence conditions.