The Lemur II-Class Robots for Inspection and Maintenance of Orbital Structures: A System Description

Abstract

The assembly, inspection, and maintenance requirements of permanent installations in space demand robots that provide a high level of operational flexibility relative to mass and volume. Such demands point to robots that are dexterous, have significant processing and sensing capabilities, and can be easily reconfigured (both physically and algorithmically). Evolving from Lemur I, Lemur IIa is an extremely capable system that both explores mechanical design elements and provides an infrastructure for the development of algorithms (such as force control for mobility and manipulation and adaptive visual feedback). The physical layout of the system consists of six, 4-degree-of-freedom limbs arranged axisymmetrically about a hexagonal body platform. These limbs incorporate a “quick-connect” end-effector feature below the distal joint that allows the rapid change-out of any of its tools. The other major subsystem is a stereo camera set that travels along a ring track, allowing omnidirectional vision. The current Lemur IIa platform represents the jumping-off point toward more advanced robotic platforms that will support NASA’s Vision for Space Exploration, which calls for a sustained presence in space. This paper lays out the mechanical, electrical, and algorithmic elements of Lemur IIa and discusses the future directions of development in those areas.