【摘要】 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。更多还原

【Abstract】 The minimum-fuel flight trajectory based on the ascending-coasting-descending mode was designed to solve the crew or cargo transportation between different areas on lunar surface.First,the optimal flight time and the corresponding two-impulse solution were obtained by solving a series of Lambert problems.Subsequently,the minimum-fuel trajectories with finite thrust were optimized via replacing the velocity impulses with finite thrusting arcs.During the process of optimization,two main challenges were addressed,namely bang-bang control and the constraints of the flight height,which were solved by numerical continuation on the acceleration amplitude and the flight time.Three numerical examples were finally presented,whose results indicated that the solution optimized based on the ascending-coasting-descending mode was also the minimum-fuel solution when the flight time was a few hours;if the distance was relatively far,the flight time should be increased to satisfy the constraints of the flight height.更多还原