Investigations into Several Approaches to EVA-Robot Integration 2007-01-3232
Extensive prior research at the University of Maryland Space Systems Laboratory has identified significant operational advantages to high levels of integration between EVA crew and dexterous robotics. Crew performance on recent Hubble Space Telescope repair missions was broken down into task primitives, and evaluated for the impact of dexterous robotics in direct support of extravehicular activity. Results demonstrate that direct EVA-robotic cooperation can increase human performance in satellite servicing tasks by factors ranging from at least 60% (for highly complex and dexterous servicing tasks) to as much as 400% for more simple activities with greater levels of planned orbital replacement unit (ORU) interchange. This paper details experimental and analytical investigations of differing approaches to adding dexterous robotic capabilities to the EVA work site, via increasingly direct integration of robotics into the space suit system itself. The Hubble analysis was based on robotically-augmented manipulator foot restraints, which can be used separately for robotic site preparation and closeout without EVA interaction, and in direct support of the EVA crew for complex and dexterous tasks. This approach was first investigated in 1989, and most recently has been the subject of extensive testing using the University of Maryland MX-2 space suit analogue in conjunction with the Ranger Dexterous Servicing System for neutral buoyancy simulations. This approach will be experimentally assessed and conceptually extended to a robotic system supporting routine EVA servicing from the planned Crew Exploration Vehicle Orion. Moving beyond worksite-integrated robotics, the concept for a “science staff” in planetary surface exploration is presented, and the results of a prototype development project are discussed. A third approach aimed at more direct EVA-robotic symbiosis involved the integration of a lightweight manipulator system directly onto the MX-2 backpack, providing additional dexterity and transport capability for the EVA crew. The manipulator can be used for carrying equipment between work sites, prepositioning components prior to final manual assembly, or providing controllable dynamic body restraint and positioning for the EVA crew. At an even greater level of EVA-robotic integration, various systems for directly integrating robotic actuators and sensors into the suit are presented, starting with augmentation of the metacarpophalangeal joint of the hand, and progressing to morphing upper torsos and arm or leg segments. Finally, the complementary approach of human augmentation of robotic systems is represented by the Space Construction and Orbital Utility Transport (SCOUT) concept, which incorporates a shirt-sleeve environment for the operator, with a pair of dexterous manipulators, a grappling arm for worksite stabilization, and direct EVA-type manual capabilities through the provision of space suit arms and helmet integral to the vehicle exterior. The paper summarizes testing of a prototype version of this system at the University of Maryland, as well as extrapolation of results to assess the potential utility of such a system in the recently published NASA architecture for future space exploration.