A deployable and Retractable Inflatable Link for a Space Robotic Manipulator

This paper presents the development of IDRA, an Inflatable and Deployable Robotic Arm for space applications. IDRA allows significant volume savings, a critical factor in space missions, and offers a workspace expansion beyond the capabilities of conventional space robotic manipulators. Moreover, its compact nature during launch offers efficient cargo space utilization, which can lead to reduced launch costs. The robot has a hybrid structure made of inflatable links and rigid electric-actuated joints. Therefore, when links are deployed, the robot has the same mode of operation of a traditional one, controlled through standard visual servoing algorithms. The ability to deploy and retract allows to occupy volume only when needed, reducing the exposure to space debris impacts and extreme conditions. IDRA can be employed in satellites with high economic value for inspection, maintenance and servicing activities to extend their operational life, contributing to the mitigation of space debris issue. In-orbit servicing, assembly and manufacturing (ISAM) is a growing trend in the space industry and new innovative, economic and sustainable systems are required to improve the sustainability of the sector. The robotic system could be deployed only when necessary and, when stored, would have little impact on the overall volume of the satellites. This paper focuses on the advancements in the design, analysis and verification of the inflatable link of IDRA, the key component that enables the efficient deployment and retraction of the robot. The link is designed to maintain structural integrity and operational precision of the robotic manipulator when inflated, conserving a cylindrical shape. A test bench has been constructed to test a planar version of the robotic system under simulated microgravity conditions, utilizing air bearings on an epoxy resin floor to minimize friction. The inflatable link is tested to validate its controllability and stability during the retraction phase. Results confirmed the functionality of the inflatable link mechanism, highlighting areas for potential refinement in future iterations to further enhance performance. Next steps regard the test of the inflatable links under extreme conditions, such as high and low temperature and vacuum.