中国空间科学技术

中国空间科学技术

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一种月面定点着陆制导的参数优化方法

王浩帆1,*，张洪华1，王泽国1，王志文1，赵宇1   

  1. 1. 北京控制工程研究所，北京 100094

  • 收稿日期:2025-12-17 修回日期:2026-01-20 录用日期:2026-02-10 发布日期:2026-07-31

A parameter optimization method for pinpoint lunar landing guidance

WANG Haofan1,*，ZHANG Honghua1，WANG Zeguo1，WANG Zhiwen1，ZHAO Yu1   

  1. 1.Beijing Institute of Control Engineering, Beijing 100094, China

  • Received:2025-12-17 Revision received:2026-01-20 Accepted:2026-02-10 Online:2026-07-31

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摘要：

针对着陆器发动机推力存在不确定性导致着陆精度差的问题，提出了一种基于递归二次规划（RQP）的动力显式制导（PEG）方法。首先，将着陆过程划分为两个不同推力大小的阶段，应用PEG求解各阶段的制导律，以推力切换时刻的高度和速度作为参数，采用RQP方法进行参数优化。在优化过程中，采用变尺度法近似估计Hessian矩阵以求解下降方向，并引入梯度裁剪与随机参数扰动策略，避免算法陷入局部最优。采用蒙特卡洛仿真验证了所提方法的有效性和鲁棒性。结果表明，所提方法对于不同期望航程、参数初值和推力偏差均能正常收敛。此外，与传统PEG方法相比较，所提方法显著降低了航程误差和燃料消耗，尽管计算时间有所增加，但仍在星载计算机进行在线制导的可接受时间范围内。 所提方法有效提升了着陆器在推力不确定性环境下的定点着陆精度，为月面软着陆任务提供了一种具有高可靠性的可行技术途径。

关键词: 推力不确定性, 定点着陆, 递归二次规划（RQP）, 动力显式制导（PEG）, 参数优化

Abstract:

To address the degradation of landing accuracy resulting from thrust magnitude uncertainty in the lander's engine, a method integrating Powered Explicit Guidance (PEG) with Recursive Quadratic Programming (RQP) is proposed. The descent trajectory was divided into two phases with distinct thrust levels. PEG was applied in each phase to generate the corresponding guidance law, with the altitude and velocity at the thrust-switching point treated as optimization variables. These parameters were optimized using RQP framework, in which the Hessian matrix was approximated via a variable-metric method to compute the search direction. To further mitigate convergence to local minima, gradient clipping and stochastic parameter perturbation were introduced. Monte Carlo simulations were carried out to validate the effectiveness and robustness of the proposed method.  The results demonstrate reliable convergence across a range of test conditions, including variations in the desired downrange, initial parameters, and thrust deviation. Furthermore, compared with the conventional PEG approach, the proposed method significantly reduces both downrange error and fuel consumption. The proposed method effectively improves the lander’s pinpoint landing accuracy in the presence of thrust uncertainty, offering a reliable and technically feasible approach for future lunar soft-landing missions.

Key words:

Thrust magnitude uncertainty, Pinpoint landing, Recursive Quadratic Programming (RQP), Powered Explicit Guidance (PEG), Parameter optimization