基于进化策略的月球软着陆探测器轨道设计

Lunar Soft-landing Trajectory Design Based on Evolutionary Strategy

应用进化策略和微分修正法建立了一套多约束、多目标条件下的月球软着陆轨道设计方法.根据中国发射场和火箭运载的实际情况,给出了软着陆轨道需要满足的过程约束及终端条件,提出了利用进化策略进行轨道初步设计,通过微分修正法对初步设计结果进行修正的软着陆轨道设计思路,并采用STK进行了仿真和结果验算.分析表明,基于进化策略的初步设计能够为微分修正提供良好的初值,保证了其收敛性.STK仿真结果验证了设计思路的有效性及结果的正确性.本文提出的方法能够为月球软着陆轨道设计提供参考.

Lunar soft-landing trajectory design methods using evolutionary strategies and differential correction are investigated. According to the launch site and vehicle of the Chinese Lunar Exploration Program, the general constraints and objectives of lunar soft-landing missions are given. The primary trajectory is calculated by evolutionary strategies based on patched conic model. Then the differential correction method is adopted to modify the error introduced by the inaccurate model. The trajectories of cislunar and lunar orbiter phase before the soft-landing are also simulated by the commercial software STK, and the feasibility of the methods delivered in this paper is confirmed by the comparison of results. The difference of parameters between the preliminary and accurate model indicates that the design based on evolutionary strategies gives a proper value for the differential correction. This approach will be significant for the lunar soft-landing trajectory design of Chinese Chang＇E Mission.