|Back-stepping Robust Control for Flexible Air-breathing Hypersonic Vehicle via a-filter-based Uncertainty and Disturbance Estimator
Yuhua Yang, Xingling Shao*, Yi Shi, and Wendong Zhang
International Journal of Control, Automation, and Systems, vol. 19, no. 2, pp.753-766, 2021
Abstract : "In this paper, a robust control scheme using back-stepping and α-filter-based uncertainty and disturbance estimator (UDE) is designed for flexible air-breathing hypersonic vehicle (FAHV) in the presence of severe external disturbances. Firstly, with the aid of back-stepping technique, the longitudinal dynamics of FAHV is separated into velocity and altitude subsystems. Feedback linearization (FL) is utilized to design control laws for each subsystem. Secondly, to enhance robustness of the controller, α-filter-based UDEs are constructed to estimate the lumped disturbances, including aerodynamic parameter uncertainties, flexible effects and external disturbances. More importantly, the performance superiority of α-filter-based UDE is clarified via frequency response analysis and comparisons with an extended state observer (ESO). Furthermore, the issue of tuning design parameter α is analyzed. The stability of closed-loop system is proved by Lyapunov stability theory. Simulation results demonstrate
the effectiveness of the proposed control strategy."
α-filter-based UDE, back-stepping control, flexible air-breathing hypersonic vehicle, frequency response, severe external disturbances.