Exponential stabilization of quad-rotor helicopter based on exact linearization and disturbance rejection with on-line estimation of disturbances

In this paper, we consider the problems of controlling both the position and the yaw angle of a quad-rotor helicopter based on exact linearization. The main contribution is to propose a new dynamic feedback controller which reduce the closed-loop system to a linear controllable state equation by changing coordinates in the state-space. This paper presents two stabilizing controllers. Firstly, a new stabilizing controller based on the LQR (Linear Quadric Regulator) is presented. Secondly, a disturbance rejection problem is considered in the presence of a persistent unknown disturbance, and a new disturbance rejection controller based on disturbance observer is presented for obtaining asymptotically rejection against unknown constant disturbance.