Attitude control for near space vehicle based on new terminal sliding mode control

The rotation motion model of un-power glide phase of near space vehicle is modeled by nonlinear dynamic equations. The model is highly nonlinear, strong coupling, and with parameters of great uncertainties. The rotation motion model could be Input/Output linearized by dynamic inversion method, which is used in inner-loop controller. A new terminal sliding mode control method is proposed. This method uses S-type function in designing nonlinear sliding surface, can ensure that the output tracking errors converge to zero along the S-type trajectory in finite time, and avoid the singular problem in normal terminal sliding mode control method. The outer-loop robustness controller is designed by S-type terminal sliding mode control method. Simulation studies demonstrate that the proposed control method, which is robust with respect to interference and parametric uncertainties, can track the commands of attitude angles accurately.