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针对重复使用运载器(RLV)的自动着陆段(A&L)提出了一种快速的轨迹生成算法。相比于传统航天飞机的策略,该方法并不依赖事先离线计算并储存好的若干轨迹,可在A&L段初始状态存在散布的条件下快速生成可行参考轨迹。首先将A&L段的参考轨迹分成由若干参数定义的分段轨迹组成。其次确定陡平衡滑翔段的航迹倾角,使RLV在此阶段动压几乎保持常值。再次从需求的着陆条件进行反向轨迹推演,一直到达圆弧拉起段的起点处。本文的轨迹生成算法通过迭代校正唯一的系数,平滑着陆段起点处的航迹倾角,直到轨迹推演终点处的动压满足陡平衡滑翔段的动压,从而保证满足A&L段接口处的边界约束。最后的仿真实验验证了该算法的快速性,有效性与鲁棒性。
A fast trajectory generation algorithm is proposed for the Automatic Landing Segment (A & L) for Reusable Launcher (RLV). Compared with the traditional space shuttle strategy, this method does not rely on a number of trajectories calculated and stored beforehand offline, so that a feasible reference trajectory can be quickly generated under the condition that the initial state of A & L is scattered. First, the reference trajectory of the A & L segment is divided into segment trajectories defined by several parameters. Secondly, the track inclination of the steeply balanced gliding segment is determined so that the dynamic pressure of the RLV remains almost constant at this stage. Reverse the trajectory again from the required landing conditions until it reaches the start of the arc pull-up. The trajectory generation algorithm of this article smoothes the track inclination at the beginning of the landing section by iteratively correcting the unique coefficients until the dynamic pressure at the end of the trajectory deduction satisfies the dynamic pressure of the steeply balanced gliding section so as to ensure that the boundary constraints at the interface of the A & L section are satisfied. The final simulation shows that the algorithm is fast, efficient and robust.