针对小天体着陆环境存在参数不确定性及初始状态偏差的特点,提出一种小天体着陆闭环优化方法,实现在节省燃料消耗的同时降低对参数的敏感度。首先,建立小天体着陆动力学模型,分析了燃料最优着陆问题;然后,采用线性二次型调节器设计了反馈制导律,推导闭环敏感度矩阵方程,构造燃料消耗和敏感度加权的性能指标,进而能够通过优化降低小天体着陆过程的敏感度。仿真结果表明,该闭环优化方法能有效降低对参数不确定性和初始状态偏差的敏感度,最终达到提高小天体着陆位置和速度精度的目标。
Since the dynamics parameters of the small bodies and the initial state of the lander are uncertain,an optimization method considering the closed-loop tracking guidance is presented. Firstly,the dynamics for landing on small bodies is constructed and the optimal problem is analyzed. Then,the feedback guidance law is designed by use of the Linear Quadratic Regulator. The closed-loop sensitivity matrix equations are derived,and the performance index with weighted fuel consumption and sensitivity is constructed. Then,the trajectory considering the closed-loop tracking guidance is obtained by solving the constructed optimal problem. The simulation results show that the presented method can reduce position and velocity errors and meet the requirements for precision landing on small bodies.