Extended state observer based control for generic hypersonic vehicles with nonaffine-in-control character

This paper investigates the flight control problem of generic hypersonic vehicles subject to nonaffine-in-control character. Considering the large uncertainties and external disturbance, the disturbance observer based control strategy is incorporated in the control scheme. Firstly, an extended state observer is used to estimate the system states and the total disturbance. Then, based on the output of the extended state observer, we follow the backstepping design procedure. The dynamic inversion method is involved in the last step of backstepping to solve the nonaffine-in-control problem. The proposed control scheme ensures that the hypersonic vehicle tracks the command signal with almost no aerodynamic knowledge. Rigorous stability proof is given based on the separated time-scale structure of the extended state observer and the dynamic inversion method. At last, numerical simulations are presented in different conditions to demonstrate the effectiveness and good tracking performance of the proposed control scheme.