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空间结构的主要动机。在这方面，充气游丝技术为轻型、可收起的卫星提供了有趣的设计，这些卫星可以在发射过程中压缩成几英寸厚的折叠堆，然后在数百英尺的太空中部署。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，提高覆盖范围，同时满足发射体积和质量目标。 虽然充气结构因其轻便的设计而备受赞誉，但由于额外的组件（如太空飞行电缆），充气结构的动态行为可能会受到显着影响。在传统的空间结构中，电缆与有效载荷的质量比可以高达20%;由于重量小得多，充气结构的这个数字将显著增加。此外，飞行计划试验表明，当结构元件与信号和电力电缆连接时，空间结构动态行为的复杂性被放大。美国空军研究实验室/VSSV也发现了这个问题，这对卫星系统的振动建模和验证及其地面发射前测试造成了重大问题。另一方面，高灵活性，小质量，高带宽控制器所需的充气式空间任务的任务，需要精确的模型来预测这些结构的高阶动力学。这对于较大的结构尤其重要，因为它们在发射前无法进行充分测试。因此，建议的研究的一个主要目标是研究空间飞行电缆对充气刚性结构及其主要部件，如充气刚性复合材料吊杆的动态效应。这项研究建立在申请人以前的研究基础上，开发基于均匀化技术和组合动力系统方法的新的分析模型，以更好地了解主机结构和控制电缆之间的动态相互作用。该研究还旨在开发具有显著更小的计算时间和更高的结合低阶振动控制算法的能力的降阶模型。通过分布参数模型的发展，在结构的动态响应的非线性，由于增加了空间飞行电缆，这些结构和实验模型验证的可能的频率相关的动态调查的阻尼特性提出了一些新的方面和短期/长期目标的拟议的研究计划。此外，拟议研究的一部分将集中在申请人对充气膜结构的形状控制的研究的继续，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. **