Abstract:

In this paper, the longitudinal flight dynamics of a waverider-class hypersonic vehicle with aerodynamics based on NASA’s Generic Hypersonic Aerodynamics Model Example (GHAME) are presented. A brief analysis on the required performance to transition from a re-entry trajectory to horizontal flying is performed, and the results are used as a desired manoeuvre to be achieved in conjunction with a flight controller. An L1 adaptive controller is applied to the vehicle to robustly track the desired manoeuvre. The L1 adaptive controller features fast adaptation, essential for a rapidly changing flight conditions, with a bounded from zero time delay margin for robustness. The ability of the controller to robustly track the manoeuvre is demonstrated through various failure modes and modelling error simulations, such as degradation of control surface effectiveness, reduced longitudinal stability margins and controller processing delays. The simulation results show the L1 adaptive controller is able to maintain stability during the different scenarios, with some performance degradation for the off-nominal scenarios.