Predictive Active Disturbance Rejection Attitude Control for 2-DOF Unmanned Helicopter with Three Typical Uncertainties

This paper considers the attitude control for 2-DOF unmanned helicopter. To handle the nonlinear uncertainties in helicopter system, active disturbance rejection control (ADRC) based attitude controller is designed. Compared with the conventional ADRC, the proposed ADRC design contains an additional predictive part for the estimated value from ESO. By utilizing the estimated value and its derivative, the predictive values of total disturbance and unmeasured angular velocity are calculated based on Taylor expansion. The presented predictive design can cancel the hysteresis phenomenon of estimation in ESO, which results in the more accurate estimation. Due to the precise estimation for total disturbance and unmeasured angular velocity, the satisfied tracking performance of presented method is validated. In simulations, the estimating and tracking performance of the presented method is shown for three typical uncertainties: step disturbances, ramp disturbances and nonlinear uncertainties.