Abstract
Focusing on the vertical return mission scenario of reusable launch vehicles, analytical guidance methods commonly adopted in existing research lack effective fuel prediction mechanisms, which severely restricts the mission reliability and fuel economy of vehicle vertical landing, and fails to achieve high-precision velocity constraint control and stable anti-disturbance guidance in the full powered descent and terminal landing process. To address the above problems, this paper proposes a multi-phase integrated guidance framework that integrates predefined-time time-varying fractional-order sliding mode control and fuel consumption forecasting. A fuel consumption prediction model incorporating potential energy factor, kinetic energy factor and interference factor is constructed to realize full-process fuel demand prediction in the trajectory planning stage, and the proposed guidance scheme achieves high-precision and strong anti-disturbance guidance performance while satisfying strict full-stage velocity constraint requirements. Simulation results show that the proposed method can realize stable and accurate vertical soft landing under diverse disturbance conditions with minor fuel prediction errors. This method addresses the limitations of traditional analytical guidance methods in terms of mission reliability and fuel economy, improves the system robustness of vertical recovery missions, and provides an effective technical reference for precise landing guidance of reusable launch vehicles.