Backstepping sliding mode control for BTT missiles based on second-order sliding mode

Based on backstepping design and second-order sliding mode control, a new backstepping sliding mode controller is designed for back-to-turn (BTT) missiles nonlinear dynamics with unmatched uncertainties. Sliding mode control is used in each step of the backstepping design to compensate for uncertainty, and nonsingular second-order sliding mode control is used in the last step of the backstepping design. In this way, the chattering problem which does harm to rudders can be avoided, meanwhile, the accumulated error is reduced.computation explosion is reduced by introducing an exact robust differentiator, and the tracking error of the system is proved ultimately bounded. Simulation result shows that the tracking errors converge to an arbitrary small neighborhood of the origin by adjusting the design parameters of the controller.