Dynamics Modelling of Ultra-light and Cable-Harnessed Space Structures: Theory and Experimental Validation

发射卫星系统的高成本一直是设计更轻的空间结构的主要动机。在这方面，可充气的游丝技术为轻型、可装载的卫星提供了有趣的设计，这些卫星可以在发射时被压缩成几英寸厚的折叠堆，然后在数百英尺的太空中展开。这种超轻技术可以为在太空中放置大型计量系统提供有前途的解决方案，同时提高覆盖范围，同时满足发射体积和质量目标。***虽然因其轻设计而备受赞誉，但充气结构的动态性能可能会受到额外组件（如太空飞行电缆）的显著影响。在传统的空间结构中，电缆与有效载荷的质量比可达20%；由于充气结构的重量更小，这个数字将显著增加。此外，飞行方案试验表明，当结构元件与信号和电力电缆相结合时，空间结构动态行为的复杂性会被放大。这个问题也被美国空军研究实验室/VSSV确定为卫星系统及其地面发射前测试的振动建模和验证的主要问题。另一方面，充气式空间任务所需的高灵活性、小质量和高带宽控制器要求需要精确的模型来预测这些结构的高阶动力学。这对于大型结构尤其重要，因为它们在发射前无法进行全面测试。因此，研究空间飞行索对可充气刚性结构及其主要部件（如可充气刚性复合臂架）的动力效应是本文研究的一个主要目标。本研究建立在申请人先前研究的基础上，开发了基于均质技术和结合动力系统方法的新型分析模型，以更好地理解主结构与线束之间的动态相互作用。该研究还旨在开发计算时间更短的降阶模型，并提高结合低阶振动控制算法的能力。通过分布参数模型的发展来表征阻尼，由于增加了太空飞行电缆而导致的结构动态响应的非线性，对这些结构可能的频率相关动力学的研究以及实验模型验证提出了一些新的方面和提出的研究计划的短期/长期目标。此外，拟议研究的一部分将集中在申请人对充气膜结构形状控制的继续研究上，以提高其天线应用的表面精度。**

The high costs to launch satellite systems have been a major motivation for much lighter space structures' designs. In this regard, inflatable gossamer technology offers interesting designs for lightweight, stow-able satellites that can be compressed into folded stacks of a few inches of thickness during launch before deployed over hundreds of feet in space. This ultra-light technology can offer promising solution for placing large metrology systems in space with improved coverage while meeting the launch volume and mass goals.*** While prized for their light designs, the dynamic behaviour of inflatable structures can be significantly impacted due to additional components such as space flight cables. The cables to payload mass ratio can be up to 20% in a traditional space structure; this number will increase significantly for inflatable structures due to much smaller weights. Additionally, flight program tests have shown that the complexities in dynamic behaviour of space structures are magnified when structural elements are harnessed with signal and power cables. This problem has also been identified by the US Air Force Research Lab/VSSV to impose major issues in vibrations modeling and verification of the satellite systems and their ground-based pre-launch tests. On the other hand, high flexibility, small mass, and high bandwidth controllers required for inflatable space missions mandate the need for accurate models to predict higher-order dynamics of these structures. This is particularly important for larger structures, as they cannot be fully tested prior to launch. Therefore, a major objective of the proposed research pertains to studying the dynamic effects of space flight cables on inflatable rigidizable structures and their major components such as inflatable rigidizable composite booms. This research builds on the previous research by the applicant to develop novel analytical models based on homogenization techniques and combined dynamical systems approaches to better understand the dynamic interactions between the host structures and the harnessing cables. The research is also aimed at the development of reduced-order models with significantly smaller computational time and increased ability to incorporate low-order vibrations control algorithms. Characterization of damping through the development of distributed parameter models, nonlinearities in a structure's dynamic response due to the addition of the space flight cables, investigation of possible frequency dependent dynamics of these structure and experimental model validations present some of the novel aspects and short/long-term goals of the proposed research program. Additionally, part of the proposed research will focus on a continuation of the research by the applicant on shape control of inflatable membrane structures to improve their surface accuracy for antenna applications. **