【作者】 沈红新；

【导师】 李海阳；

【作者基本信息】 国防科学技术大学 ， 力学， 2009， 硕士

【摘要】 所谓定点返回,是指返回飞行器能够在预定着陆区着陆。对于载人登月任务来说,研究定点返回问题对回收搜救、测控网布置等都具有重要的意义。本文以解决载人登月定点返回轨道问题为目的,系统研究了定点返回轨道基本特性、月地转移轨道设计和优化、再入段轨道特性分析和制导律设计。全文主要工作包括:研究了和定点返回相关的轨道参数特性。(1)引入月球反垂点概念,具体分析了月球反垂点和再入点、近地点的位置关系;(2)基于月球反垂点分析再入航程和倾角的性质;(3)研究了再入点速度、再入点纬度参数设计的相对稳定性规律;(4)根据月相原理和轨道特性,描述返回窗口和光照条件的定性关系。研究给出了月球定点返回轨道设计方法(不包含轨道面机动情形)。(1)提出了基于双二体假设的分层搜索和角动量-能量守恒两种轨道初步设计方法;(2)提出了考虑地球扁率修正的多圆锥截线返回轨道设计方法;(3)研究了结合修正多圆锥截线法猜测初值和微分修正的两步规划高精度轨道设计方法,仿真计算表明了此方法的有效性。研究给出了定点返回轨道考虑轨道面调整情形时的月地轨道射入(TEI)优化设计方法。(1)研究了TEI调整轨道面的三种变轨方案,对变轨方案进行特性分析;(2)将高斯伪谱法扩展应用到多相最优控制问题进行脉冲推力轨道优化设计,主要分析了求解多相最优控制问题的联结条件处理方法;(3)提出了基于脉冲分布特性和GPM多相算法的适于大轨道面调整的三脉冲TEI优化设计方法。研究了登月返回飞船弹道升力式再入轨道的参数特性。(1)提出基于高斯伪谱法求解登月返回舱再入轨道,此方法可弥补传统方法初值选取、计算效率上的不足;(2)从轨迹优化的角度研究了登月飞船的再入轨道特性;(3)研究了升阻比确定的原则和方法。研究提出了基于标称轨道制导思想设计登月飞船返回舱再入制导律。(1)提出了更适合于登月飞船的线性倾侧角取值方案,应用Newton-Raphson算法求得设计变量初始倾侧角;(2)通过误差源的综合影响分析,研究了登月返回舱标称轨道制导律的纵程和横程偏差;(3)讨论了影响倾侧角变化率的因素,研究了调整反馈增益系数和减小倾侧角变化率及制导精度的关系。总之,本文在载人登月轨道问题方面取得了一些进展,所做工作可为我国未来的载人登月定点返回技术的突破和掌握提供理论参考和技术支持。更多还原

【Abstract】 What is called point return is that the ability to land at a desired destination. The point return technique emphasizes on manned lunar landing mission special value on recovery and disposal of telemetry, track, command, etc. For the purpose of solving the orbit characteristics and design problem, this dissertation studies point return orbit elementary characteristics, Moon-to-Earth orbit design and optimization, reentry orbit characteristics analysis and guidance approach design. The main results achieved in this dissertation are summarized as follows.The elementary characteristics of point return orbit for a vehicle from a lunar mission are studied. (1) By importing the concept of lunar antipode, the relative location between the entry point, perigee and lunar antipode are analyzed with detail; (2) The connection of flight range and the inclination is given basing on the analysis of lunar antipode; (3) The stabilization performance of the latitude and velocity at entry point is get; (4) The relation between lighting condition and return window is also analyzed qualitatively using the principle of lunar phase.The orbit design method for lunar point return orbit is studied and provided(No consideration is given to the use of orbital plane changes to ensure proper point return). (1) Two methods to analyze inbound trajectory are proposed, which are the double two-body hypothesis based methodology; (2) The patched multi-conic method including the Earth’s oblateness effect is proposed to optimize point return orbit; (3) The two-step planning method for high-fidelity orbit design is proposed incorporating modified patched multi-conic method and differential-corrector method, the numerical simulation shows that this method is effective.The optimal design method of Trans-Earth Injection(TEI) considering the plane change is studied and provided. (1) Three orbit plane change approach for TEI is presented, the maneuver characteristics is also analyzed; (2) The optimal design for optimal impulsive orbit transfer is proposed by applying the GPM on multiphase optimization, and the emphasis is placed on the connecting condition at knots; (3) Basing on the location characteristics of impulses and multiphase GPM, the three impulse TEI which is suited for large plane change is designed.The reentry parameters characteristics of ballistic lift lunar return module is studied. (1) The method for solving reentry trajectory using Gauss pseudospectral method is proposed, this method can remedy the deficiency of traditional method on initial guess and computational efficiency; (2) The reentry trajectory characteristics of lunar return module are studied basing on trajectory optimization. (3) The choice principia and method of lift-to-drag ratio is studied.The reentry guidance approach is studied and provided based on predetermined path following concept. (1) The nominal linear bank angle approach which is more suited than determined as constant is proposed, and the initial bank angle is solved by Newton Raphson algorithm; (2) By error analysis integrated all the guidance error, the downrange and cross range error for lunar return module is studied; (3) The factors impact on bank rate are discussed, The relation between the feedback gain factor regulation and the guidance precision is studied.In conclusion, important developments have been achieved for the returning orbit from the Moon to a specified landing site for manned lunar-landing mission. The method and conclusions in this thesis would be available for in theory and practice for the lunar return mission.更多还原