Nair Manu Harikrishnan, Rai Mini Chakravarthini, Poozhiyil Mithun
Lincoln Centre for Autonomous Systems, University of Lincoln, Lincoln, United Kingdom.
Front Robot AI. 2022 Oct 14;9:995813. doi: 10.3389/frobt.2022.995813. eCollection 2022.
In-Space Services aim to introduce sustainable futuristic technology to support the current and growing orbital ecosystem. As the scale of space missions grows, there is a need for more extensive infrastructures in orbit. In-Space Assembly missions would hold one of the key responsibilities in meeting the increasing demand. In the forthcoming decades, newer infrastructures in the Earth's orbits, which are much more advanced than the International Space Station are needed for manufacturing, servicing, and astronomical and observational stations. The prospect of in-orbit commissioning a Large Aperture Space Telescope (LAST) has fuelled scientific and commercial interests in deep-space astronomy and Earth Observation. However, the assembly of such large-scale, high-value assets in extreme environments, like space, is highly challenging and requires advanced robotic solutions. This paper introduces an innovative dexterous walking robotic system for in-orbit assembly missions and considers the Large Aperture Space Telescope system with an aperture of 25 m as the use case. The top-level assembly requirements are identified with a deep insight into the critical functionalities and challenges to overcome while assembling the modular LAST. The design and sizing of an End-over-end Walking Robot (E-Walker) are discussed based on the design of the LAST and the specifications of the spacecraft platform. The E-Walker's detailed design engineering includes the structural finite element analysis results for space and earth-analogue design and the corresponding actuator selection methods. Results of the modal analysis demonstrate the deflections in the E-Walker links and end-effector in the open-loop due to the extremities present in the space environment. The design and structural analysis of E-Walker's scaled-down prototype is also presented to showcase its feasibility in supporting both in-orbit and terrestrial activities requiring robotic capabilities over an enhanced workspace. Further, the mission concept of operations is presented based on two E-Walkers that carry out the assembly of the mirror modules. The mission discussed was shortlisted after conducting an extensive trade-off study in the literature. Simulated results prove the dual E-Walker robotic system's efficacy for accomplishing complex assembly operations through task-sharing.
太空服务旨在引入可持续的未来技术，以支持当前不断发展的轨道生态系统。随着太空任务规模的扩大，轨道上需要更广泛的基础设施。太空组装任务将在满足不断增长的需求方面承担关键责任之一。在未来几十年里，地球轨道上需要比国际空间站先进得多的新型基础设施，用于制造、服务以及天文和观测站。在轨道上调试大口径空间望远镜（LAST）的前景激发了对深空天文学和地球观测的科学及商业兴趣。然而，在太空这样的极端环境中组装如此大规模、高价值的资产极具挑战性，需要先进的机器人解决方案。本文介绍了一种用于轨道组装任务的创新型灵巧步行机器人系统，并以口径为25米的大口径空间望远镜系统为例进行探讨。通过深入了解模块化LAST组装过程中的关键功能和需要克服的挑战，确定了顶层组装要求。基于LAST的设计和航天器平台的规格，讨论了端到端步行机器人（E-Walker）的设计和尺寸确定。E-Walker的详细设计工程包括空间和地球模拟设计的结构有限元分析结果以及相应的执行器选择方法。模态分析结果表明，由于空间环境中的极端条件，E-Walker连杆和末端执行器在开环状态下会产生挠度。还展示了E-Walker缩小比例原型的设计和结构分析，以证明其在支持需要机器人能力的轨道和地面活动方面的可行性，且工作空间得到了扩展。此外，基于两个执行镜模块组装任务的E-Walker，提出了任务操作概念。在对文献进行广泛的权衡研究后，所讨论的任务被列入候选名单。模拟结果证明了双E-Walker机器人系统通过任务分担完成复杂组装操作的有效性。
