Variable gain nonlinear switching controller design for near space vehicles

According to the characteristics of variable-sweep wings near space vehicles, such as large flight envelop, multiple work modes and model uncertainty, the attitude robust tracking control problem in the process of mode change is considered. The nonlinear switching model of the vehicle containing disturbances is established. The robust controller is designed based on the backstepping sliding mode method and nonlinear disturbance observer. By means of the common Lyapunov function theory, it is proved that the designed control law can guarantee the stability of the close-loop switching system. The variable gain control strategy is employed to design the appropriate control gains for different flight modes, which improves the dynamic performance of the system.Simulation results show the effectiveness and necessity of the proposed method.