Abstract:

 A novel prescribed performance controller is addressed for the longitudinal dynamics of a hypersonic vehicle with large uncertainties and multi-constraints in this paper. Firstly, both the transient and steady performance of the altitude and velocity tracking errors are guaranteed in the pre-selected bounds by utilizing the newly proposed time-varying barrier Lyapunov function-based dynamic surface control. Compared with the traditional prescribed performance technique, the proposed algorithm does not need error transformation and thus reduces the design complexity. Then, the upper bounds of the uncertainties are estimated and introduced into the control law by exploiting the adaptive nonlinear disturbance observer. In addition, an auxiliary error compensation design, which can alleviate the effectiveness of actuator saturations, is employed based on the compensated tracking error. Finally, the ultimately boundedness of the closed-loop system is rigorously ensured by the Lyapunov stability theorems. The numerical simulation results validate the effectiveness of the proposed method.

Key words: Hypersonic vehicle, Prescribed performance, Time varying barrier functions, State constraint, Disturbance observer