Abstract: The configuration of an X-20-like hypersonic vehicle is researched. By a deep analysis on the relationship of the aerodynamic coefficients with the altitude, Mach number, angle of attack, angle of sideslip and the deflection of the control surfaces, a series of simplified analytical polynomial functions of these variables are fitted. For the controller design, the increments of the control surfaces are treated as the control input. Based on the fitted polynomial expressions and the control inputs, an affine nonlinear model of the hypersonic vehicle is established. This control model is proved to be approximately linearized, thus the feedback linearization method could be designed. Under uncertainties of atmospheric density, aerodynamic moment coefficient and the moment of inertial, the control law for the original dynamic model is simulated. Considering the effect of the earth rotation and the aerodynamic model, simulation of the original model is established by the coefficients lookup tables. The simulation results demonstrate that the control objectives can be achieved and the controller is proved to be robust.

Key words: hypersonic vehicle, feedback linearization, aerodynamics coefficients fitting