Planning and Execution of Tele-Robotic Maintenance Operations on the ISS

摘要

The Mobile Servicing System (MSS) is a complex robotic system used extensively in the assembly, inspection and maintenance of the International Space Station (ISS). With the ISS construction now complete, the focus of MSS operations has shifted from assembly support to external maintenance activities. In 2011, the MSS successfully completed its first two logistics and maintenance operations using the Dextre robot: the relocation of new ISS components, delivered by the Japanese H-Ⅱ Transfer Vehicle, and the removal and replacement of a failed ISS power controller module. This paper describes the planning and execution of Dextre's first tele-robotic operations. It summarizes the significant technical challenges encountered and presents the operational techniques developed to overcome them. Ground-controlled operations are shown to be an effective method to maximize external maintenance capability, and therefore ISS lifetime, as well as on-orbit crew availability for science activities. It is found that components designed to be robotically-serviceable can frequently present unforeseen challenges, driving the need for flexible operational tools and techniques, such as the use of force/moment sensing and accommodation. As a result, the approach developed for Dextre lends itself readily to future ISS maintenance tasks, but also to more general robotics exploration and satellite-servicing missions.