A High Gain Observer and Sliding Mode Controller for an Autonomous Quadrotor Helicopter

This paper deals with the design of a high gain observer and sliding mode controller for a remotely controlled quadrotor vertical take off and landing aircraft. Under the restriction that only the inertial coordinates and yaw angle are available for measurement, a high gain observer is designed which allows estimating on-line the roll and pitching angles as well as all the linear and angular velocities of the vehicle. The problem is solved in two steps: first, a high gain observer design is carried out by means a change of coordinates of the quadrotor system. Second, a dynamic sliding mode controller is proposed using the state estimate of the quadrotor helicopter. We show the asymptotic stability of the couple observer–controller. Finally, computer simulations are developed for showing the performance of the proposed observer–based control.