Observer based backstepping control for a three degree of freedom model helicopter

In this paper, an observer based backstepping control method is applied to the attitude control of a three degree of freedom (3DOF) model helicopter with unknown external disturbance and modeling uncertainties. A disturbance observer is designed to approximate the unknown external disturbance and modeling uncertainties. A state observer is developed to estimate the unmeasurable states. The stability of closed-loop system is proved by Lyapunov method. Simulation results are given to show the effectiveness of the proposed controller for the 3DOF model helicopter with unknown external disturbance and modeling uncertainties.