Characteristic model-based adaptive discrete-time sliding mode design for hypersonic vehicle attitude control

A novel robust adaptive control scheme is developed based on the characteristic modeling and discrete-time sliding mode control theory, for the attitude control of a hypersonic vehicle with parameter uncertainties and time-variation. The characteristic model of the hypersonic vehicle is derived considering the control objective and the vehicle feature firstly. Then a discrete-time sliding mode control law with a recursive form is proposed on the basis of the characteristic model, to enhance the control performance and system robustness to inevitable uncertainties. The main advantage of our proposed robust adaptive control scheme is that no knowledge of the boundaries and variation rate of parameter uncertainties is required in advance. Using the Lyapunov stability theory, the closed-loop system is proved stable and convergence properties of the system are assured. Finally, the simulations results demonstrate the effectiveness of the robust adaptive control scheme.