Nonlinear tracking control of hypersonic flight vehicle subjected to hyperbolic zero dynamics via output regulation theorem

The standard output regulation theorem is utilized to construct a nonlinear flight tracking controller for a hypersonic vehicle in presence of non-minimum phase dynamic in the paper. When the elevator is chosen as the only control surface, the hypersonic vehicle model exhibits unstable hyperbolic zero-dynamics, preventing the application of standard inversion-based control technique. The standard nonlinear output regulation theory is introduced to design a flight controller, achieving asymptotic tracking of velocity and altitude in a climbing maneuver case. Moreover, a Taylor-expansion-based approximation method is presented to solve the center manifold equation for the output regulation problem. Finally, Numerical simulations in Matlab/Simulation Environment validate the effectiveness of the proposed controller in resisting unstable zero dynamics and providing favorable tracking performance.