载人登月绕月自由返回轨道混合-分层优化设计

Hybrid and Two-Level Optimization Design of Circumlunar Free-Return Trajectory for Manned Lunar Landing Mission

针对载人登月绕月自由返回飞行任务,提出一种混合-分层轨道优化设计方法。将高精度模型下强约束自由返回轨道设计问题转化为有约束非线性规划求解问题,在此基础上提出一种混合-分层优化求解策略。在双二体模型下利用差分进化算法(DE)与序列二次规划(SQP)相结合的混合优化算法快速求解了满足弱约束条件下的轨道初值问题。采用序列二次规划(SQP)构造两层迭代格式,在高精度模型和强目标约束下对初步设计轨道进行逐层修正。最后,通过仿真测试,文章所述方法的可行性与有效性得到了验证。仿真飞行结果还进一步表明该设计方法具有求解精度高、收敛速度快等优点,为探月工程任务提供了一种有效的轨道设计工具。

An optimization method of trajectory design is established in this paper for manned lunar landing circumlunar free-return flight mission. The problem of designing free-return trajectory with multiple constrains under the high precise dynamic model is converted to the nonlinear bounded optimization problems. A solving strategy consisting of hybrid and two- level optimization algorithm is then proposed. Under the double two-body model, the initial trajectory with the weak constrain conditions is obtained by hybrid optimization algorithm which consists of differential evolution （DE） method and sequence quadratic program （SQP） method based on the patched-conic approach. Then a two-level initial trajectory corrective measure based on the sequence quadratic program is applied to obtain the final solution satisfying the strong engineering constrains under the high precise dynamic model. Finally, the reliability and effectiveness of the approach proposed in this paper are demonstrated by the simulation tests, and the results indicate that the proposed method has excellent convergence performance and high precision, thus can be a useful tool for manned lunar orbit design.