Robust tracking control of a quadrotor helicopter without velocity measurement

In this paper, a robust output tracking controller for quadrotor helicopter is proposed. The proposed controller requires measurement of only four state variables: positions in inertial coordinate frame and yaw angle. Also, the controller is robust to unmodeled dynamics and provides rejections of all external force and torque disturbances. The effectiveness of the proposed controller is tested on a simulation example of quadrotor tracking under wind influence which is modeled as unmatched external force disturbances in horizontal plane.