嫦娥三号软着陆轨道设计与控制策略

摘要

The problem of guidance and soft landing control of Chang ’e-3 flight is solved. The kinematics difference equation is established to minimize the fuel consumption. The optimal control strategy for the posi-tion of the landing preparatory orbit and the main deceleration stage is determined by iterating with MATLAB. In the obstacle avoidance stage, the optimal threshold is selected based on the discrete two-dimensional en-tropy and the safe landing point is selected by the spiral search method. According to the principle of dynam-ics, the engine thrust size, direction from the six stages of soft landing and the time and fuel consumed are calculated, and the trajectory equation is given. Finally, error analysis and sensitivity analysis about the calcu-lation results are made.%解决嫦娥三号飞行的制导与软着陆控制问题。建立运动学差分方程，以燃料消耗量最小为目标，利用 MATLAB实施迭代，确定着陆准备轨道的位置和主减速段的最优控制策略；在避障阶段，基于离散二维熵的最优阈值选择模型，采用螺旋搜索方法选定安全着陆点；根据动力学原理，算得软着陆6个阶段的发动机推力大小、方向以及消耗的时间与燃料，并给出运动轨迹方程；最后，对计算结果做出误差分析和敏感性分析。