Active Disturbance Rejection Control Design of the Yaw Channel for a Small-scale Helicopter based on Backstepping

This paper focuses on the active disturbance rejection control method of the yaw channel for a small-scale helicopter. Firstly, the comprehensive nonlinear model of the yaw kinematics and dynamics is derived, which considers the nonlinear characteristics and cross-axis couplings fully. Then, considering the unmodeled dynamics and external disturbances, the model is simplified reasonably and the controller is designed by backstepping technique incorporating with two nonlinear extended state observers, which are used to estimate and dynamic compensate the lumped disturbances. The stability of the closed-loop system is proved rigorously by the Lyapunov stability theory, and the error range of convergence is also derived. At last, flight simulations are carried out to validate the effectiveness and robustness of the proposed controller. The results show that the proposed controller can deal with the uncertainties effectively and achieve well performance.