Stiffness of an EVA glove: objective evaluation and testing procedures

Hand fatigue is one of the major problems of astronauts during Extravehicular Activity (EVA), due to the stiffness of the space suit, in particular of the glove. In order to evaluate the stiffness of EVA gloves, different methods have been proposed in the past, mainly focused on the effects of wearing an EVA glove on hand performance when executing test protocols. In this paper, an objective method for the evaluation of the stiffness of EVA gloves is proposed, by means of a tendon-actuated finger probe. The finger probe is equipped with accelerometers, to measure the angles of its phalanges. These are actuated by applying different torques using the finger probe tendons. The EVA glove is tested in both pressurized and non pressurized conditions, thanks to a hypobaric glove box. An Orlan-DM EVA glove is tested and stiffness results are presented. This setup can be used for different kinds of gloves, not necessarily for EVA application, and allows direct, numerical measurement of their stiffness.