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针对月球表面不同区域之间的载人或载货运输问题,设计了一种基于上升-巡航-下降模式的燃料最省飞行轨迹。首先通过求解不同飞行时间的Lambert问题确定了最佳飞行时间,并获得了对应的双脉冲解,然后利用有限推力替代两次速度脉冲,建立了非线性规划问题,求解得到了有限推力燃料最省飞行轨迹。优化设计过程中主要研究了两个主要难点:bang-bang控制与飞行高度约束。这两个问题通过推力加速度与飞行时间的数值延拓得以解决,同时揭示了月面飞行的基本原理。最后给出了3种不同应用场景的仿真算例,仿真结果表明,当飞行时间为小时量级时,上升-巡航-下降飞行模式下的优化解即为燃料最优解,如果飞行距离较远,则还需要适当增加飞行时间从而满足飞行高度约束。
Aiming at the problem of manned or laden transport between different regions of the lunar surface, a fuel-saving flight trajectory based on ascent-cruise-descent mode was designed. Firstly, the optimal flight time is obtained by solving the Lambert problem with different flight time, and the corresponding two-pulse solution is obtained. Then the finite-thrust is used to replace the two-speed pulse, a nonlinear programming problem is established. The finite thrust fuel Flight path. In the optimization design process, two major difficulties are mainly studied: bang-bang control and flight altitude constraints. These two issues are solved by the numerical extension of thrust acceleration and time of flight, revealing the rationale of lunar flight. Finally, the simulation examples of three different application scenarios are given. The simulation results show that when the flight time is in the order of hours, the optimal solution in the ascent-cruise-descent flight mode is the fuel optimal solution. If the flight distance is farther , You also need to increase the flight time to meet the flight height constraints.