Anti-disturbance control of hypersonic vehicle considering input saturation

Abstract

The problem of adaptive tracking control for hypersonic vehicles with input saturation constraints and mismatched disturbances is studied. Firstly, the longitudinal hypersonic vehicle model is transformed into a linear form with mismatched disturbance by feedback linearization method. Then, a high-order disturbance observer is established to estimate the mismatched disturbances and their high-order derivatives quickly online. Based on the disturbance observation information, a new sliding mode surface is designed to ensure the stability and control accuracy of the system state under the action of external disturbance. At the same time, the input saturation problem is transformed into the time-varying gain problem by means of the mean value theorem, and the gain is estimated online by the adaptive law of Nussbaum function, and the actual stability of the closed-loop system under input saturation constraint is proved. Simulation results show that the proposed method can guarantee the good tracking performance of the aircraft considering input saturation and external disturbance.