Fixed-time attitude control of reusable launch vehicles utilizing reliability-based control allocation

Reusable launch vehicles (RLVs) offer advantages such as low cost and high efficiency, yet they still face challenges related to real-time precise control and reliability enhancement. To address these issues, this paper presents a fixed-time attitude control method designed for RLVs, incorporating a reliability-based control allocation scheme. Initially, a fixed-time radial basis function neural network (RBFNN) disturbance observer is introduced to estimate disturbances rapidly and accurately. Subsequently, a control method integrating non-singular terminal sliding mode control (NTSMC) with a saturation compensator is proposed to achieve real-time and precise angle tracking. Furthermore, a reliability-based control allocation scheme is employed to enhance the reliability of the attitude control system. Finally, simulation analysis is conducted to validate the effectiveness of the proposed control scheme.