Immersion and invariance based nonlinear adaptive control of hypersonic vehicles

A theoretical framework of nonlinear adaptive flight control is addressed and applied to a generic Hypersonic Flight Vehicle longitudinal model. A combination of dynamic inversion technology and back-stepping is adopted for designing a dynamic state-feedback controller that provides stable tracking of the velocity and altitude reference trajectories. The new type of nonlinear parameter estimator based on immersion and invariance (I&I) methodology is constructed to guarantee the parameter estimate errors can convergent to zero and the performance of closed-loop system is satisfied. A Lyapunov-based stability analysis of closed-loop system is derived. The proposed methodology is verified in numerical simulations in a climbing maneuver case of separate velocity and altitude reference commands.