A research platform for investigating human position sense in altered gravity conditions for space applications and beyond

Abstract

With ever increasing complexity and distance of space exploration missions, telerobotics will continue to play an important role. By pairing more capable multi-modal user interfaces with teams of dexterous intelligent robotic assets, astronauts are able to perform a wide variety of remote tasks in the space environment on orbit or celestial surface. In several telerobotics technology demonstration missions carried out on the International Space Station (ISS) such as Haptics 1 [28] and 2 [29], Kontur-2 [3], SUPVIS Justin, Analog-1 [28], and Surface Avatar [11], we have continuously advanced the capabilities in commanding complex robotic assets and teams. In these experiments, different modalities of user interfaces, including intuitive graphical user interfaces, a joystick and kinesthetic interfaces were deployed to examine their effectiveness in microgravity conditions for direct motion control of robotic assets. The immersive robot command with force-reflection is a valuable command modality for non-repetitive exploratory tasks, or in other unknown situations. However, we also observed pro-prioceptive performance degradation of astronauts when teleoperating on board the ISS. These performance erosions are believed to originate from a degraded sensory state in the human user´s limb. In order to study the effects of altered gravity on the human´s position sensing systematically, a research platform was designed allowing test subjects to perform the standard test procedures for measuring human limb position sense in micro- and hypergravity conditions as experienced during parabolic flight. This paper details and discusses the research platform designed to fulfill requirements resulting from precautions for parabolic flights and quality standards in proprioceptive test procedures. The mechatronic requirements, challenges and solutions for such a test setup are specified and described. The developed research platform enables the investigation of the human´s position sensing and the physiological mechanisms in altered gravity conditions. As such, the research platform will play a key role in our user interface design for future space telerobotic applications.