Adaptive Attitude Control for a Kind of Rotating Rockets with Improved Disturbance Observer

Considering nonlinear, multivariable coupling and parameter uncertainty in the nonlinear dynamic system of rotary rockets, an improved nonlinear disturbance observer (IDO) was proposed to approximate the high-frequency disturbance. A backstepping sliding mode controller is designed with the proposed disturbance observer to prevent cumulative tracking errors from guidance signals. The stability of this control system is proved with the Lyapunov function. The simulation results show the efficient performance of the backstepping sliding mode control with the proposed IDO method.