基于组合优化策略的月球软着陆最优轨道设计

基于Pontryagin极大值原理,把求解月球软着陆燃料最优化问题归结为终端自由型两点边值问题.采用粒子群算法和单纯形算法接力优化的组合优化策略,在初始猜测值的邻域内进行搜索,充分利用粒子群算法的全局搜索能力迅速缩小搜索范围,然后利用单纯形算法的局部搜索优势快速获得优化结果.该优化策略最大的优势是使粒子群算法的全局搜索能力和单纯形算法的局部搜索能力同时得到最大化的发挥.仿真证明该优化方法在考虑一些实际工程约束的情况下,能较快速而准确的获得月球软着陆优化轨迹,具有一定的优越性.

Optimization of lunar soft landing trajectory based on combinational algorithm

Based on the Pontryagin’s maximal principle, the fuel optimal lunar soft landing problem can be simplified as a two point boundary value problem with variable final time. The initial adjoint variables were listed by searching the neighborhood of guessed adjoint variables with the employment of the combinational algorithm, which is combined with particle swarm optimization (PSO) for reducing the territory of searching region and simplex method (SM) for decreasing the time of obtaining suitable results. The most valuable advantage of the combinational algorithm is that both the globe searching and local searching are utilized at the same time. The simulation results show that the combinational algorithm used for designing the soft landing trajectory gives good performance on steady, efficiency and accuracy, even some practical constraints are under considered.