Robust adaptive terminal control for near space vehicle based on second order sliding mode disturbance observer

A robust adaptive terminal controller is proposed for attitude system of near space vehicle. Firstly, NSV dynamic model is presented, which includes nonlinear, uncertainty and disturbance. Secondly, an second order sliding mode disturbance observer is used to estimate the unknown disturbance. Then, in order to overcome the chattering problem in traditional sliding mode, the design process of second-order dynamic terminal sliding mode controller is given by constructing terminal sliding mode surface based on PI sliding mode surface. Finally, the simulation results show the good tracking control performance of the proposed method.