Practical predefined-time barrier function-based adaptive sliding mode control for reusable launch vehicle

This paper proposes a novel barrier function-based adaptive sliding mode control scheme with practical predefined-time convergence for reusable launch vehicles subject to parametric uncertainties and external disturbances. Distinguished from existing similar works, the proposed control scheme ensures that the attitude tracking errors converge to a pre-assigned region in a prescribed time without any prior information on the lumped disturbance, and the control gain is not overestimated. Firstly, a novel performance function with quantitatively predefined convergence time and steady-state error is designed to constrain the attitude tracking errors, and the equivalent unconstrained transformation is carried out for the constrained model. Subsequently, a novel adaptive sliding mode controller is devised for the transformed system by synthesizing the integral sliding mode paradigm and the barrier function-based adaptive gain technique. The stability of the controller is analyzed by the Lyapunov method. Finally, comparative numerical simulation results are presented to demonstrate the effectiveness and improved performances of the proposed control scheme.