UDE-based adaptive dynamic surface control for attitude-constrained reusable launch vehicle

This paper presents an adaptive dynamic surface control scheme for vertical takeoff and landing reusable launch vehicles (VTLVs) with unknown disturbances, model uncertainties, and an attitude constraint to achieve exact attitude tracking control in the aerodynamic descent phase. First, the six-degree-of-freedom dynamic model of the VTLV is established. Next, the unknown disturbances and model uncertainties in the VTLV model are considered as the total disturbances, which are estimated by employing an uncertainty and disturbance estimator to compensate the controller, thereby enhancing the control accuracy of the system. Moreover, a symmetric time-varying barrier Lyapunov function is utilized to cope with the attitude-constrained problem. Finally, the high tracking performance of the proposed adaptive dynamic surface controller is verified by numerical simulation results.