Finger Exoskeleton – Towards an EVA Exoskeleton Hand Analysis, Modelling, Design and Implementation

EVA (Extra Vehicular Activity) is an operation done by astronauts away from the Earth, and outside of a spacecraft, using a spacesuit that is composed by a complex and highly technological multi-layer structure designed to protect the astronauts from several factors due to the outer hostile environment. Besides providing good comfort, it must be internally pressurized in order to keep the astronauts safe from the effects caused by the vacuum outside the spacecraft. All these factors impose strong limitations on the astronauts’ mobility and dexterity during a mission, in particular the gloves, that are the most critical part of the space suit because they are indeed required for exploration related to human activities, requiring a major force to perform a single movement due to the increment of the stiffness of each joint causing the astronauts’ fatigue, becoming one of the main problems that limits the overall duration of spacewalks. Therefore a device able to reduce the hand’s fatigue, during EVA missions would be a significant improvement for the astronauts, increasing working hours with more comfort, allowing them to accomplish their task in a more efficient way, improving finally the crew productivity. The topic of the thesis is the development of a prototype of a lightweight hand exoskeleton designed to be embedded in the gloved hand of an astronaut and to overcome the stiffness of the pressurized space suit. The system should be able to provide force and precision to the handgrip and in particular able to sense the willingness to move the hand.