Guidance and control system design for hypersonic vehicles in dive phase

A six-degree-of-freedom (6DoF) guidance and control (G&C) scheme for a hypersonic vehicle in the dive phase is proposed in this paper. The 6DoF translational and rotational dynamic and kinematical equations of the hypersonic vehicle are formulated. The intuitive analytical expressions of the 6DoF aerodynamic coefficients of a generic hypersonic vehicle (GHV) are presented. A two-loop control structure is applied for actualizing the 6DoF G&C scheme. The outer loop generates the commands of the angle of attack and the bank angle with the help of the terminal sliding mode control theory and frame system transformation. The inner loop tracks the anticipant Euler angles provided by the outer loop and deduces the required right elevon, left elevon, and rudder fin deflections. Furthermore, the aerodynamic uncertainties and dynamic model uncertainties are accounted for, and extended state observers are employed to estimate these unknown uncertainties. Finally, the effectiveness and robustness of the proposed 6DoF G&C scheme are verified and investigated using the GHV and 6DoF nonlinear simulations.