Abstract: To ensure a good scramjet inlet environment, a hypersonic vehicle should be controlled as a fine attitude control. But the elastic vibration greatly influences the accuracy of attitude control. Taking the longitudinal channel of hypersonic vehicle for example, the impact of elastic problem on the flight control system is analyzed and a elastic aerodynamic model is established in this paper. Considering the large-scale perturbation of model parameters caused by body/engine coupling and aerodynamic heating, the fine attitude control system is designed base on robust H∞ theory and LQR theory under a active control strategy. Simulation results show that, under the condition of measurement noise, nonlinear actuator and large-scale perturbation of model parameters, the rigid body angle of attack is tracked exactly and the flexible angle of attack is well suppressed. The Control accuracy of local angle of attack of inlet is within ± 0.4 degrees, and can meet the requirements for fine attitude control.

Key words: Hypersonic vehicles, Vibration modeling, Fine attitude control, Active control, Robust control