挠性卫星姿态机动的快速高精度控制方法

Push-broom imaging mode and staring-imaging mode of LEO in current space missions need the capability of fast attitude maneuver. Moreover the high pointing accuracy is also demanded in imaging missions. In order to deal with the need demanded by dynamic imaging, this project would design rapid and high accuracy attitude control strategy. First the finite-time state observer for flexible modal would be designed based on flexible model and angular velocity feedback. The model uncertainty would be taken into consideration and robust observer would be constructed. Based on the modal estimation, the vibration perturbation in dynamic model could be suppressed. Second, the analytical angular velocity trajectory would be designed with acceleration process, maneuver process and deceleration process. System would stay at the maneuver process as long as possible to improve the maneuver time. The acceleration and deceleration process would be optimized to suppress the flexible model vibration. Then finite-time adaptive attitude tracking controller would be designed to ensure that system would maneuver along the designed trajectory. Moreover, the adaptive law for system inertia uncertainty would be added in the controller to suppress the perturbation brought by system uncertainty. The continuous controller based on adaptive law would be discussed and high frequency vibration would be avoided. The purpose of this project is to solve the scientific issue of fast attitude maneuver under system model uncertainty and flexible vibration perturbation. The result of this project could support rapid and high accuracy satellite attitude control issue from method and theoretical aspects and lay the foundation for practical engineering applications.

空间任务中推扫成像、低轨凝视成像模式要求卫星平台具有姿态快速机动的能力，同时对姿态控制的动态精度提出了较高要求。针对这些需求，本课题将设计动态条件下快速、高精度的姿态控制方法。首先将根据角速度反馈信息，基于姿态系统模型设计鲁棒有限时间观测器以实现对振动模态的快速准确估计，进而在控制器中添加挠性估计项消除振动对系统的扰动；随后设计具有解析形式的卫星姿态机动路径，确定加减速与匀速过程切换点，延长匀速运动过程以提升系统收敛时间，并对加减速过程进行优化以减小角速度变化带来的挠性附件振动；最后引入自适应控制，设计有限时间自适应更新律以抑制模型不确定性带来的扰动，实现真实轨迹对参考路径的快速、高精度跟踪，最终实现动态条件下卫星姿态机动的快速高精度控制。本课题旨在解决挠性卫星姿态快速机动面临的基础科学问题，其研究成果将为卫星姿态机动的快速、高精度控制提供必要的方法、理论支持，并为实际工程应用打下基础。

针对空间任务中推扫成像、低轨凝视成像等任务对卫星平台提出的能力要求，研究考虑挠性附件的大角度姿态快速机动控制方法。.首先根据角速度反馈信息与挠性附件动力学模型设计有限时间状态观测器，利用姿态动力学与挠性附件模型的耦合与角速度反馈设计分数阶状态观测器，并证明了观测器的有限时间稳定性；随后利用欧拉刚体转动原理与相继转动方法将一般的姿态机动拆分成三次连续的Bang-Bang式机动，考虑系统能力上界并进而求出具有时间较优特性的姿态机动路径解析解；最后基于分数阶反馈设计有限时间PD+控制器，将有限时间控制器末端收敛速率快的优势与PD控制器结构简单鲁棒性强的优势相结合，给出了一种具有简单结构的有限时间控制器，在考虑模型不确定性与外部扰动的条件下实现了系统状态对于参考轨迹的跟踪。.通过数值仿真验证了本次研究所提出理论方法的有效性与优越性。本项研究所提出方法在大角度姿态机动条件下（机动角度大于60度）相比较于传统PD控制器收敛速率提升50%以上，同时稳态精度在保持原精度的条件下有所提升。.本此研究所提出的理论方法解决了挠性卫星姿态大角度快速机动所面临的基础理论问题，为其实际工程应用打下了基础与铺垫，在实际工程与国防民生领域具有广泛的应用前景与较高的应用价值。