During the last decades the number of human space missions has increased significantly. In many of these missions, astronauts are sent to space in order to carry out some specific tasks like installation of different units or parts to the international space station and/or repair and maintenance of its different parts. In order to do these tasks, astronauts have to go outside of the spacecraft. All the activities that astronauts perform outside of the spacecraft are called Extra Vehicular Activity (EVA). To do EVA, astronauts have to be protected from dangerous condition of space. Some outstanding elements that distinguish the space environment and make it dangerous are radiation, zero pressure and micrometeoroids. These elements are very harmful for human being and in order to protect human body from this harsh condition, astronauts have to wear a specific suit when they go out of the spacecraft to do EVA. Astronaut’ space suit is designed to protect astronauts from this harsh environment. The thickness of a spacesuit is approximately 3/16 inches (4.8 mm) and it is fabricated by sewing and cementing 11 layers of different materials. Moreover, some metal parts are used to join different parts of the suit together. In addition, the spacesuit has to be pressurized internally in order to compensate the vacuum of the space and keep astronaut alive. This heavy, thick and multilayer suit prevents astronauts moving their body easily. This is also true for the astronauts’ gloves. Due to the bulk and stiffness of this glove, so called Extravehicular Activity (EVA) glove, many problems occur during their missions outside the spacecraft. Hand fatigue, dexterity reduction of the fingers and consequently decrease of possible EVA hours are some of these problems. Several solutions have already been proposed to solve the problem. One approach tries to decrease this stiffness by adopting a suit with Mechanical Counter Pressure (MCP) instead of gas (oxygen) pressure. Other solutions attempt to overcome the existing stiffness of the gloves by means of external devices such as hand exoskeletons which support human fingers during flexion. Here a comprehensive research regarding the second solution is performed. In other words, overcoming the stiffness of the astronauts EVA glove by means of an external device is investigated. Therefore, in the first chapter the problem is explained completely and in the second chapter the possible solutions are evaluated. State of the art in this field is also discussed in this chapter. The main stream of discussion starts in chapter three. Evaluation of the EVA glove effects on the hand performance is explained in this chapter followed by measuring the stiffness of the EVA glove in chapter four. Study of the kinematics of the finger joints is covered in chapter five. In chapter six, a test bed is designed and realized to simulate the stiffness of the EVA glove and finally design of two compatible structures for this application is explained in chapter seven.

DESIGN AND REALIZATION OF A FINGER EXOSKELETON FOR ASTRONAUTS EXTRAVEHICULAR ACTIVITY (EVA) GLOVE / SEYED MOUSAVI, MOHAMAD MEHDI. - STAMPA. - (2013).

DESIGN AND REALIZATION OF A FINGER EXOSKELETON FOR ASTRONAUTS EXTRAVEHICULAR ACTIVITY (EVA) GLOVE

SEYED MOUSAVI, MOHAMAD MEHDI
2013

Abstract

During the last decades the number of human space missions has increased significantly. In many of these missions, astronauts are sent to space in order to carry out some specific tasks like installation of different units or parts to the international space station and/or repair and maintenance of its different parts. In order to do these tasks, astronauts have to go outside of the spacecraft. All the activities that astronauts perform outside of the spacecraft are called Extra Vehicular Activity (EVA). To do EVA, astronauts have to be protected from dangerous condition of space. Some outstanding elements that distinguish the space environment and make it dangerous are radiation, zero pressure and micrometeoroids. These elements are very harmful for human being and in order to protect human body from this harsh condition, astronauts have to wear a specific suit when they go out of the spacecraft to do EVA. Astronaut’ space suit is designed to protect astronauts from this harsh environment. The thickness of a spacesuit is approximately 3/16 inches (4.8 mm) and it is fabricated by sewing and cementing 11 layers of different materials. Moreover, some metal parts are used to join different parts of the suit together. In addition, the spacesuit has to be pressurized internally in order to compensate the vacuum of the space and keep astronaut alive. This heavy, thick and multilayer suit prevents astronauts moving their body easily. This is also true for the astronauts’ gloves. Due to the bulk and stiffness of this glove, so called Extravehicular Activity (EVA) glove, many problems occur during their missions outside the spacecraft. Hand fatigue, dexterity reduction of the fingers and consequently decrease of possible EVA hours are some of these problems. Several solutions have already been proposed to solve the problem. One approach tries to decrease this stiffness by adopting a suit with Mechanical Counter Pressure (MCP) instead of gas (oxygen) pressure. Other solutions attempt to overcome the existing stiffness of the gloves by means of external devices such as hand exoskeletons which support human fingers during flexion. Here a comprehensive research regarding the second solution is performed. In other words, overcoming the stiffness of the astronauts EVA glove by means of an external device is investigated. Therefore, in the first chapter the problem is explained completely and in the second chapter the possible solutions are evaluated. State of the art in this field is also discussed in this chapter. The main stream of discussion starts in chapter three. Evaluation of the EVA glove effects on the hand performance is explained in this chapter followed by measuring the stiffness of the EVA glove in chapter four. Study of the kinematics of the finger joints is covered in chapter five. In chapter six, a test bed is designed and realized to simulate the stiffness of the EVA glove and finally design of two compatible structures for this application is explained in chapter seven.
2013
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2506466
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