被动输入过约束空间多环耦合构架式航天可展天线机构关键技术研究

The truss space deployable antennas have received many in-orbit applications at home and abroad, which is one of the most important means of achieving the large-diameter and high-precision antennas in the future. The mechanism of the truss deployable antennas is more complicated than that of traditional parallel and hybrid mechanisms, since it has spatial multi-loop coupling kinematic chains. At present, there are very few literatures focusing on the DoF (degree of freedom) analysis and type synthesis of this kind of antenna mechanism. Besides, for the mechanism of the truss space deployable antennas, there exist redundant actuations during the deploying process. It is worth noting that the actuations of this kind of mechanism are passive, so that it is called as overconstrained mechanism with passive inputs in this project. There is almost no study on the statically indeterminate force problem and configuration coordination of this kind of special overconstrained mechanism. Therefore, this project will explore the method for the DoF analysis and type synthesis of the spatial multi-loop coupling mechanism of the truss deployable antennas, aiming to establish the corresponding theoretical system. Moreover, the basic principle of the driving torques distribution and variation during the deploying process of this overconstrained mechanism of deployable antennas with passive inputs will be analyzed, the internal forces will be re-defined from the perspective of motion coordination, the control strategies will be designed to reduce or even eliminate the internal forces, so that the coordinated and smooth motion of the truss deployable antennas can be achieved. The research results will provide a theoretical guidance and technical support for the design and development of the truss space deployable antennas.

构架式航天可展天线在国内外已经获得了多次在轨应用，是未来大口径、高精度天线的重要实现手段。该类天线机构为空间多环耦合机构，比传统的并联和混联机构复杂很多，而国内外关于空间多环耦合机构自由度分析与构型综合的研究非常少。此外，构架式航天可展天线机构展开过程存在驱动冗余，但是驱动方式是被动的，这里称之为被动输入过约束机构，目前关于这种特殊过约束机构展开过程静不定力学及位形协调问题的研究几乎空白。因此，本项目拟研究空间多环耦合构架式可展天线机构的自由度分析手段，探索构架式可展天线机构的构型综合方法，建立系统的空间多环耦合可展天线机构自由度分析与构型综合理论体系；分析被动输入过约束可展天线机构展开过程驱动力矩分配与变化的基本原理，从运动协调角度重新定义机构内力，设计驱动策略以降低甚至消除机构内力，从而实现天线协调、平稳地展开。研究成果将为构架式航天可展天线的设计及开发提供重要的理论指导与技术支撑。

构架式航天可展天线刚度大、型面精度高、折叠比大，是高精度航天可展天线的最重要的结构形式。该类天线机构由多个基本单元通过一定的机构学原理组合而成，属于空间多环耦合机构，是最为复杂的空间机构，其构型综合、运动学分析和动力学分析都具有相当大的难度。此外，构架式可展天线机构大多采用被动元件作为驱动器，且驱动器数大于机构自由度数，属于被动输入过约束机构，展开过程受力分析相当复杂。中小口径的构架式可展天线在国内外已经获得了一定数量的在轨应用，但由于其基础理论方面的研究成果较少，天线的构型数量极其有限，并严重影响在轨展开的可靠性，尤其是严重制约高精度大口径构架式可展天线的研发。鉴于目前国内外关于大型构架式可展天线机构的构型综合、自由度分析及静不定力学问题等方面的研究非常少，本项目对空间多环耦合构架式可展天线机构的设计与分析问题开展了深入、系统的研究：研究构架式可展天线机构构型综合方法，研究空间多环耦合可展天线机构及一般空间多环耦合机构的自由度分析手段，建立系统的自由度分析与构型综合理论体系；研究构架式可展天线机构展开过程驱动器输入位移与展开节点位置、姿态、速度之间的解析关系式；建立构架式可展天线机构展开过程多体动力学模型，研究被动输入过约束可展天线机构展开过程驱动力矩分配与变化的基本原理；研究大型可展天线机构程序化建模技术及运动学和多体动力学仿真；加工制造最小组合单元机构样机一台，搭建实验平台，进行自由度验证实验、卸载实验和模态实验。通过上述研究，本项目建立了空间多环耦合构架式航天可展天线机构系统的自由度分析与构型综合理论体系，且为一般空间多环耦合机构的自由度分析提供新的途径，得到了一系列新型具有多自由度的航天可展天线机构，揭示了构架式航天可展天线机构的运动机理，获得了被动输入过约束可展天线机构展开过程的驱动力分配与变化原理。研究成果为研发具有我国自主知识产权的构架式可展天线提供重要理论指导与技术支撑。