Robust attitude control of a quadrotor helicopter with unknown parameters

This paper presents a practical design approach to achieve the robust attitude control for a quadrotor helicopter with unknown parameters. This control method results in a linear time-invariant robust controller which is independent of the helicopter parameters. It consists of a proportional-derivative (PD) controller and a robust compensator. One can tune the PD controller parameters of each channel separately in the hover condition; then, the parameters of the robust compensator can be tuned online monotonously in trajectory tracking. It is proven that attitude tracking errors can converge to given neighborhoods of the origin. Experimental results demonstrate the effectiveness of this control method.