Output feedback back-stepping control for a generic Hypersonic Vehicle via small-gain theorem

A nonlinear controller is exploited and analyzed for the nonlinear longitudinal dynamics of a generic Hypersonic Vehicle in this paper. The vehicle model is nonlinear, multivariable and unstable. A combined nonlinear observer and back-stepping technique is adopted for designing a dynamic output-feedback controller that provides stable tracking of the velocity and altitude reference trajectories. The stability analysis of the closed-loop system and the convergence of the system outputs are verified based on the small-gain theorem. Numerical simulation results from the nonlinear model illustrate the effectiveness of the proposed control scheme.