3种六自由度动力下降凸优化制导方法  

Three convexification-based methods for six-degree-of-freedom powered descent guidance

作　　者：王驰 刘伟 高扬[1,2] WANG Chi;LIU Wei;GAO Yang(School of Aeronautics and Astronautics,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Space Utilization,Technology and Engineering Center for Space Utilization,Chinese Academy of Sciences,Beijing 100094,China)

机构地区：[1]中国科学院大学航空宇航学院,北京100049 [2]中国科学院空间应用工程与技术中心太空应用重点实验室,北京100094

出　　处：《北京航空航天大学学报》2025年第4期1292-1303,共12页Journal of Beijing University of Aeronautics and Astronautics

基　　金：中国科学院青年创新促进会项目(292020000040)。

摘　　要：飞行器动力下降软着陆的一个关键技术在于实时求解六自由度(6-DoF)动力下降制导问题,该问题可以描述为多约束条件下的燃料最省轨迹优化问题。选取飞行时间、时间替代变量、轨迹高度3种自变量建立3种优化模型,将原始轨迹优化问题转化为序列凸优化可解形式进行迭代求解,形成了3种在线制导方法。比较3种制导方法在收敛性、实时性、最优性及求解精度上的差异,结果表明:3种制导方法均能求解六自由度动力下降问题;自变量为飞行时间的制导方法计算时间最短且燃料消耗最少,但需要预先确定动力下降飞行时间;基于其余2类自变量的制导方法能够优化动力下降飞行时间,但均为次优解,且计算时间显著增加;相同离散点数量下3种方法的求解精度相近。若采用序列凸优化作为动力下降在线制导方案,如何确定最优飞行时间、逼近燃料最优解及进一步缩短计算时间等仍有待深入研究。A key technology for the safe landing of spacecraft in powered descent is to solve the six degrees of freedom(6-DoF)powered descent guidance problem in real time.This problem is a fuel-optimal problem with multiple constraints.In this paper,three optimization methods are established by three independent variables,namely flight time,time substitution variable,and height.Three onboard navigation techniques are created by transforming the trajectory optimization issue into a form that can be solved by successive convexification algorithms.The comparative analysis shows that all three methods can solve the 6-DoF powered descent problem.Although the flight time must be known beforehand,the optimization with flight time as an independent variable has the maximum computing efficiency and the lowest fuel use.The other two optimizations can optimize the flight time,but both are sub-optimal solutions,and the computation time is greatly increased.The accuracy of the three methods is similar under the same number of discrete points.If successive convexification algorithms are used as the online guidance algorithms for power descent,problems such as how to determine the optimal flight time,approach the optimal fuel solution and shorten the calculation time still need to be further studied.

关 键 词：六自由度 动力下降 自主制导 凸优化 最优飞行时间 

分 类 号：V448.131[航空宇航科学与技术—飞行器设计] V448.233