Nonlinear predictive attitude control with a disturbance observer of an unmanned helicopter on the test bench

The paper presents a nonlinear predictive controller with a disturbance observer, which is based on the dynamically extended attitude system, to cope with the problem of the attitude control of an unmanned helicopter on the test bench. The implied integral action of the disturbance observer can eliminate the system steady state error effectively. The effect of the zero points of the closed-loop transfer function on the transient response is eliminated by modifying the initial value of the disturbance observer. And no on-line optimization is required because the controller has an analytical optimal form. Finally, the controller performance is validated by experiments and compared with PID controller and the predictive controller without the disturbance observer.