Robust Trajectory Linearization Control of Hypersonic Entry Flight Using Extended State Observer and Time-varying Bandwidth

A robust trajectory linearization control (TLC) scheme is presented for a generic hypersonic vehicle (GHV) entry flight. The basic TLC frame constructs a baseline controller for the GHV attitude system, providing local closed-loop exponential stability along nominal trajectories. Then two strategies are integrated with the basic TLC for robustness enhancement. For one thing, to cope with diverse perturbations, extended state observer is designed to yield a compensation control law. For the other, an adaptive time-varying bandwidth algorithm is developed, which can not only avoid actuator saturation and integrator windup, but most importantly, also improve system robustness when huge dynamic pressure variation occurs during entry flight. This integrated robust TLC scheme can guarantee a better control performance and a larger stability domain. At last, the great advantages of the proposed robust TLC scheme is demonstrated via three groups of simulation, including a three-DOF attitude tracking, a BTT-180 maneuver simulation, and a six-DOF integrated guidance and control test.