Aerodynamic Coefficients Modeling and Attitude Controller Design for an Air-breathing Generic Hypersonic Vehicle

A rotational attitude controller scheme for an air-breathing generic hypersonic vehicle (GHV) is proposed in this paper. The compact analytical models of the GHV's aerodynamic moment coefficients are established based on the least square error criterion and quasi-newton modified method, and the inherent relations between aerodynamic moment coefficients and control surfaces are converted into an approximate linear form. For implementing the disturbance rejection control scheme, an Euler angle sliding surface vector is conducted and the pseudo-commands with respect to roll, yaw, and pitch rates are derived. Then, the sliding surface vector of the three-channel body rates is designed. A control allocation method is derived and the commanded control surface fin deflections are denoted. In derivation, the model and aerodynamic uncertainties are estimated by extended state observers. The actual control surface fin deflections are denoted via a second order actuator model. Finally, the effectiveness and robustness of the newly proposed control scheme are verified and validated using nonlinear simulation studies.