Integrated guidance and autopilot for hypersonic vehicles in dive phase using back-stepping L1 adaptive control

This paper proposes a novel integrated guidance and autopilot (IGA) method for hypersonic vehicles in dive phase. The third order back-stepping L1 adaptive control is implemented to deal with the uncertainties of aerodynamics coefficients, degradation of control surface efficiency and unmatched time-varying disturbances in the nonlinear flight dynamics. Furthermore, a second order actuator dynamics is considered. Nonlinear differentiator is used to avoid directly differentiating to the control surface deflection command, and then terminal sliding mode control is designed for the actuator to track the command. Through a series of 6-DOF numerical simulations, it's indicated that the proposed method successfully cancels out the uncertainties and disturbances in hypersonic flight. The contribution of this paper lies in the application and determination of nonlinear integrated design of guidance and control system.