• 制导、导航、控制与电子 •

月球探测器动力下降段最优轨迹参数化方法

1. 1.哈尔滨工业大学深空探测基础研究中心，哈尔滨 150001；
2. 陕西省组合与智能导航重点实验室，西安 710000；
3. 济南大学自动化与电气工程学院，济南 250022
• 收稿日期:2020-05-25 修回日期:2020-10-09 出版日期:2021-06-15 发布日期:2021-07-22
• 基金资助:
国家自然科学基金（61374213，61573247）；陕西省组合与智能导航重点实验室开放基金（SKLIIN 20180208）

Control Variables Parameterization Method of Powered Descent  Trajectory for Lunar Explorer

QIAO Yan di, ZHANG Ze xu, DENG Han zhi, XU Tian lai

1. 1. Deep Space Exploration Research Center, Harbin Institute of Technology, Harbin 150001, China; 2. Shannxi Key Laboratory of  Integrated and Intelligent Navigation, Xi’an 710000, China; 3. University of Jinan School of Electrical Engineering, Jinan 250022, China
• Received:2020-05-25 Revised:2020-10-09 Online:2021-06-15 Published:2021-07-22

Abstract: In this paper, considering the sufficient height and velocity margin of a lunar explorer entering the attitude adjustment phase, an improved polynomial guidance law is proposed, which is solved by the control variables parameterization method in the task of achieving the powered descent phase of soft landing of a lunar explorer. Firstly, the dynamics model of the lunar explorer is described in a three dimensional coordinate system. Secondly, we transform the guidance law for the landing guidance problem into the minimum fuel problem of the optimal vertical attitude angle control problem. Then, we use the control vector parameterization method to solve the optimal control problem, in which we formulate the constraints and the control vector into the nonlinear programming method as the planning parameters, furthermore, the time scaling method to split up the time, to get the precise numeric results. The Monte Carlo simulation experiments show that the guidance method proposed in this paper can accomplish the soft landing of the lunar explorer, compared with the traditional polynomial law, in less fuel consumption. While changing the initial height within ±20% before the powered down phase of the lunar explorer in the simulation, the algorithm proposed can still satisfy the soft landing task with high precision speed and height index.