Fast tracking control of air-breathing hypersonic vehicles with time-varying uncertain parameters

Abstract

Despite advantages of air-breathing hypersonic vehicles (AHVs) over turbojet-powered or rocket-powered vehicles, the control system design is still a challenge. In particular, the existing control methods lack an effective mechanism to handle time-varying uncertain parameters in the control-oriented AHV model. This study proposes a longitudinal control strategy for AHVs focusing on time-varying uncertain parameters, fast tracking and low computational complexity. The adaptive law is designed to estimate the norm bound of the vector of uncertain parameters, in which case parametric variations are accommodated with a large reduction on the dimension of the resulting control algorithm. By utilizing sliding mode exact differentiators, the analytic differential computation on virtual controls is avoided in the adaptive back-stepping design for altitude tracking. It is shown that both velocity and altitude tracking errors converge into the prescribed sets in finite time. A simulation study on the high-fidelity AHV model is provided to verify the proposed control strategy.