Anti-saturation Sliding Mode Control with Preassigned settling Time for Hypersonic Aircraft

In this paper, a model of the attitude control system for a second-order hypersonic aircraft with uncertainty is presented, and an adaptive anti-saturation sliding mode control law is designed to make the attitude angle error of the aircraft reach the specified accuracy within the preassigned settling time. The adaptive law is designed to estimate the upper bound of system interference and the sliding mode use saturation function instead of sign function to decrease the chattering phenomenon. In addition, the desaturation auxiliary system in the control system is designed. When the control input is saturated, it can quickly exit from saturation. Theoretical analysis and simulation results show that the control law can meet the above control requirements and has good robustness. Compared with the control law without auxiliary system, the control input can exit saturation more quickly.