可回收火箭大气层内动力下降的多阶段鲁棒优化制导方法

This paper proposes a multi-stage robust optimization (RO) method for the endoatmospheric powered descent problem of reusable rockets. Due to the unknown wind field in the atmosphere, it is of great significance to consider this uncertainty during the rocket descent phase. Firstly, a model of uncertain wind field with respect to altitude is established, and a robust optimal control problem for rocket powered descent is formulated under this wind field. To solve this problem, a tractable single-stage RO algorithm is developed by approximating the inequality constraints using a first-order expansion and incorporating the first-order term as a safety margin. Secondly, an upper bound on the safety margin is quantitatively derived. Based on this upper bound, a multi-stage RO algorithm is proposed, which avoids the infeasibility problem caused by the excessively large safety margin in the single-stage RO algorithm. Finally, simulation results are presented to compare the performance of each algorithm under various actual wind fields. The results demonstrate that the proposed multi-stage RO method achieves both high landing accuracy and robustness against different wind fields.