非一致终端约束下火星大气进入段制导律设计

On Guidance Algorithm for Martian Atmospheric Entry in Nonconforming Terminal Constraints

针对小升阻比的火星探测器在火星大气进入过程中所面临的难点问题,对火星大气进入过程制导方法进行了研究。首先在确知探测器弹道系数和升阻比的前提下,考虑过程量及开伞条件约束,优化设计再入飞行的初始再入角。然后考虑非一致终端约束和飞行器的有限机动能力,设计参考轨迹剖面,并确保其能提供足够的裕度来应付各种参数不确定性。最后设计标准轨道法制导律,完成轨迹有效跟踪,并通过六自由度仿真验证了算法的合理性,为火星着陆项目中大气进入段制导方案设计提供参考。

A method for Martian atmospheric entry guidance is researched in this paper,regarding the problems faced byMars exploration vehicle with low lift-to-drag ratios. Firstly,with a certain ballistic coefficient and lift-to-drag ratios,the initialreentry angle is designed considering the process variable constrains and the parachute deployment constrains. Then the referencetrajectory is developed for providing the sufficient margin to overcome the parameter uncertainties considering the nonconformingterminal constrains and the low control authority. Finally, the tracking guidance law is presented. The six degree of freedomsimulation demonstrates the effectiveness of the approach,which provides references to the Mars exploration project.