深空环境下绳系卫星动力学建模与控制研究

We address the problem of the dynamic modeling and controller design for tethered satellite system near libration points in deep space environment. Besides, the station-keeping and reconfiguration strategy design for multi-tethered satellite system using Coulomb force are also investigated in the case of relatively short distance among different satellites. Compared with the traditional satellite, the tethered satellite system possesses special advantages, say, for example, the energy saving as well as the variable baseline can be achieved by deploying or retracting the tethers. Therefore, it has tremendous potential in the applications of future space exploration. The libration point orbits are inherently unstable Non-Keplerian orbit, which is very different from low earth orbits. There are a great number of difficulties in dynamic analysis and controller design of tethered satellite system. To solve some key problems in this research field, the attitude and orbit model of some tethered satellite systems with several specific configurations will first be constructed by the application of certain basic principles in mechanics, and then, the nonlinear dynamic analysis will be conducted. Further, we choose the numerical periodic orbits with high precision as nonminal reference orbits. Thus, the station-keeping controllers for tethered satellite system will be designed based on nonlinear control and optimal control theories. Furthermore, the application of the Coulomb force instead of the traditional tether equipment to control the configuration, the relative speed and relative position of the system will also be studied. The research not only has the value of theoretical significance, but also has wide application prospects in deep space.

研究深空环境下绳系卫星平台以及平动点附近绳系卫星的动力学与控制器设计问题，并考虑在卫星之间距离较近的情况下，利用库仑力完成多体绳系卫星的形状保持与重构的设计问题。与传统卫星相比，绳系卫星系统具有特殊的优势，比如可通过系绳展开/回收获得可变基线，并可以节省燃料，在未来空间应用上具有巨大的潜力。为解决本领域当前存在的一些突出问题，本课题首先从力学基本原理出发，有针对性地建立几种特殊构型的绳系卫星系统的姿态和轨道物理模型，并进行非线性的动力学分析。在此基础上，采用高精度的平动点数值周期轨道作为目标参考轨道，应用非线性理论和最优控制理论设计绳系卫星系统的轨道保持控制器。进一步应用库伦力代替传统的物理系绳装置连接一组卫星，控制卫星系统的形状、相对速度与位置以完成预定的目标任务。从国内外研究现状来看，该研究不仅具有重要的理论研究价值，还具有广阔的深空应用前景。

绳系卫星系统作为多体航天器编队中的一种特殊形式，与自由编队飞行相比具有控制精度高，节约燃料等优点，因其编队构型保持和重构方面的优势，在未来深空探测任务中具有较大的应用潜力。但由于系统的复杂性与多样性，需要根据具体的绳系卫星系统结构与目标，进行动力学建模分析与控制器设计来满足任务需求。为解决本领域当前存在的一些突出问题，本课题对深空环境下多体旋转绳系卫星系绳平台的姿态控制问题、多体库仑卫星系统的相对位置控制问题、二体绳系卫星系统平动点附近的轨道保持控制问题进行了深入研究，完成了全驱动和欠驱动多体旋转绳系卫星姿态动力学建模与鲁棒最优控制方法研究、基于反步法和非线性模型预测控制的多约束库仑卫星系统的相对位置控制方法研究以及圆形限制性三体问题下的二体绳系卫星平动点附件的周期性轨道保持控制方法研究，达到了预定计划要求，该研究具有重要的理论研究价值，为我国绳系卫星系统在深空探测中的应用奠定了研究基础。