Adaptive modal suppression for hypersonic aeroelastic vehicle

To ensure a good scramjet inlet environment, a hypersonic vehicle should be controlled as a fine attitude control. For uncertainties of aerodynamic and structural parameters of the hypersonic vehicle, a fine attitude control system including a robust H_∞ filter, a rigid body controller, a modal observer and a structure filter, is designed based on the adaptive modal suppression theory. The robust H_∞ filter is used to estimate modal states of the rigid body, the designed rigid body controller LQR is used to improve the tracking performance and the modal observer is used to estimate the bending mode frequency. Simulation shows that, in the ± 20% random perturbation of aerodynamic parameters and ± 30% random perturbation of modal parameters, the rigid angle of attack (AOA) is tracked accurately, and the flexible AOA is well suppressed. The accuracy of local AOA in scramjet inlet is ± 0.6 degree, which can meet the demand of fine attitude control.