Spacesuit Hard Upper Torso Assembly: Development Of Fit Metrics And Customized Design Frameworks

The Hard Upper Torso (HUT) of the spacesuit pressure garment is a central component of a spacesuit, enclosing the upper body and connecting with the shoulder joints, bearings, helmet, hatch, and waist-brief-hip components. The shape and positioning of the HUT and its connected components are critical for ensuring comfort, range of motion, field of view, and minimizing astronaut injury risk.This dissertation aims to build upon previous work on spacesuit sizing and develop new spacesuit fit metrics. Motion-tracking technology has been utilized to define the reach envelope and range of motion for test subjects wearing a HUT. Subjective surveys have also been conducted to evaluate suit mobility, feature alignment, indexing, and discomfort. These tools can be adapted to investigate the effects of HUT sizing, leading to the proposal of new metrics ideal for the fit and mobility of HUT based on these technologies. Additive manufacturing can be employed to create custom spacesuit hardware with minimal additional manufacturing steps. This technique enables efficient testing and benchmarking of a wide variety of HUT prototypes. With the development of fit and performance metrics, it becomes logical to utilize these metrics to design optimally sized HUT geometry. The above goals were pursued through the following activities: 1. Define two separate HUT design frameworks: The first framework will result in an optimally distributed discreet HUT sizing system, while the second will establish a framework for the rapid prediction and design of customized HUTs. 2. Investigate the subjective effect of HUT customization on HUT fitment using a subjective fit survey, demonstrating the benefits of HUT customization. 3. Explore the effect of HUT customization using human in-the-loop testing, including range of motion and reach envelope analyses, highlighting the benefits of HUT customization on suited mobility. 4. Confirm the preliminary feasibility of 3D printed HUTs through stress analysis of virtual HUT prototypes using a range of pressures, shell thicknesses, and candidate materials

The effects of controlled environmental and physical factors on the physiological responses of the handfinger system

Hand injuries account for a leading cause of occupational injuries requiring treatment from United States\u27 hospital emergency departments. These occupational injuries generate a substantial burden on employers in terms of both cost and productivity. Occupational safety gloves are an effective preventive measure of these hand and finger injuries. However, these occupational safety gloves can result in unintended injuries due to factors such as extreme conditions of temperature, relative humidity, and physical demand. The purpose of this study is to collect data on the physiological responses of the hand-finger system and their relationship with these identified factors. The physiological responses measured were skin conductance, blood perfusion, and perceived discomfort. A chamber was used to isolate human subjects\u27 hands and precisely control the conditions of temperature and relative humidity to replicate the internal conditions within occupational safety gloves. Seventeen human subjects each performed three hours of experimental trials that routinely required the physical exertion of lateral pinching. The microclimate condition of temperature was shown to have a significant effect on perceived discomfort and skin conductance. The microclimate condition of relative humidity was shown to have a significant effect on skin conductance. The occupational condition of repetitive physical demand was shown to have a significant effect on perceived discomfort, skin conductance, and blood perfusion. The results of this study may assist ergonomists in selecting or suggesting occupational gloves for workers while minimizing risk of injury

Hand exo-muscular system for assisting astronauts during extravehicular activities

Human exploration of the Solar System is one of the most challenging objectives included in the space programs of the most important space agencies in the world. Since the Apollo program, and especially with the construction and operation of the International Space Station, extravehicular activities (EVA) have become an important part of space exploration. This article presents a soft hand exoskeleton designed to address one of the problems that astronauts face during spacewalks: hand fatigue caused by the pressurized EVA gloves. This device will reduce the stiffness of the spacesuit glove by counteracting the force exerted by the pressurized glove. To this end, the system makes use of a set of six flexible actuators, which use a shape memory alloy (SMA) wire as the actuating element. SMAs have been chosen because some of their features, such as low volume and high force-to-weight ratio, make them a suitable choice taking into account the constraints imposed by the use of the device in a spacesuit. Besides describing the different mechanical and electronic subsystems that compose the exoskeleton, this article presents a preliminary assessment of the device; several tests to characterize its nominal operation have been carried out, as well as position and force control tests to study its controllability and evaluate its suitability as a force assistive device.The research leading to these results has received funding from the STAMAS (Smart Technology for Artificial Muscle Applications in Space) project,** funded by the European Union's Seventh Framework Program for Research (FP7) (Grant No. 312815)

Glove Exoskeleton for Extra-Vehicular Activities: Analysis of Requirements and Prototype Design

The objective 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 hand grip. The project involves various elements, in particular the analysis of the characteristics of the hand and of the EVA glove. Moreover solutions related to sensor and actuator should be investigated. Finally the study and the design of an appropriate robotic structure able to fullfit the requirements have to be performed

Mathematical Modeling and Empirical Validation of a Conceptual Exoskeleton for Astronaut Glove Augmentation

Space presents numerous difficulties for astronauts conducting their work, not the least of which is the spacesuit that is worn to protect them from space. It has long been known that a spacesuit is difficult to work in, especially the rigid and pressurized gloves that put strain on the astronaut\u27s hands, frequently leading to injuries. Astronaut gloves inhibit more than 50% of their strength in some cases [1]. NASA and other space agencies have been working to alleviate these problems by attempting to mechanically augment the gloves to reduce the exertions of the astronaut. To date, no augmentation systems have been implemented into spacesuits and prototypes are actively undergoing design and development [2] [3]. Currently existing prototypes are impractical, unconformable, or not effectively augmenting the astronaut as evidenced by the non-implementation of such systems to date. This work presents a novel conceptual exoskeleton design for astronaut glove augmentation and a mathematical model that is used to predict its performance. In addition, experiments were conducted to validate the math model. The conceptual exoskeleton is designed to overcome the shortcomings of previous attempts to augment astronaut gloves by using rigid linkages actuated by a single tendon routed through them. This system operates exclusively on the dorsal surface of the hand, limiting the restrictions to the palmar surface of the hand. The mathematical model presents a method to equate the tendon tension to the contact force between the linkages and the object that is being grasped. Two representative models of the conceptual exoskeleton were built and tested. The experimental fixture, custom designed and fabricated, used a Pliance Pressure Pad to measure the total forces produced by the system. The measured force values were then compared to predictions made by the system to assess the accuracy of the mathematical model. The experimental configurations of the systems were measured using a machine vision system. The mathematical model was shown to accurately predict the contact forces produced by the representative test rigs. Relationships between the contact forces developed in a grasp and the readings from a Jamar Grip Dynamometer were then used to estimate the magnitude of grip strength that the full exoskeleton could develop [4]. These estimations indicate that the conceptual system would be able to recover up to 124% of the strength that astronauts lose to their gloves

DEVELOPMENT OF AN ADDITIVELY MANUFACTURED RIGID SPACESUIT COMPONENT FOR LONG DURATION MISSIONS

Gemstone Team SPACELong duration human exploration of Mars will pose demands on spacesuits that current designs are unable to overcome, including the need for in-situ replacement and repair of suit components. Advancements in additive manufacturing (AM) technologies provide capabilities to repair or replace rigid pressure garments on-site and on-need. This thesis focuses on a potential application for in-situ hard suit manufacturing: the integration of AM components into a functional spacesuit arm. Material tests were conducted and top candidates were selected for the joint segment components. AM bearing con figurations were tested under operational loads and seals were incorporated for pressure retention. Selected components were integrated into a hard suit arm, which was compared to the Shuttle-era EMU arm through human tests in a pressurized glove-box. The results indicate that further re finement of hard suits has the potential to match the performance of operational EMU models while reducing the logistical issues with current spacesuits

Hybrid Enhanced Epidermal Spacesuit Design Approaches

A Space suit that does not rely on gas pressurization is a multi-faceted problem that requires major stability controls to be incorporated during design and construction.The concept of Hybrid Epidermal Enhancement space suit integrates evolved human anthropomorphic and physiological adaptations into its functionality, using commercially available bio-medical technologies to address shortcomings of conventional gas pressure suits, and the impracticalities of MCP suits. The prototype HEE Space Suit explored integumentary homeostasis, thermal control and mobility using advanced bio-medical materials technology and construction concepts. The goal was a space suit that functions as an enhanced, multi-functional bio-mimic of the human epidermal layer that works in attunement with the wearer rather than as a separate system. In addressing human physiological requirements for design and construction of the HEE suit, testing regimes were devised and integrated into the prototype which was then subject to a series of detailed tests using both anatomical reproduction methods and human subject

Design of a shape memory alloy actuator for soft wearable robots

Soft robotics represents a paradigm shift in the design of conventional robots; while the latter are designed as monolithic structures, made of rigid materials and normally composed of several stiff joints, the design of soft robots is based on the use of deformable materials such as polymers, fluids or gels, resulting in a biomimetic design that replicates the behavior of organic tissues. The introduction of this design philosophy into the field of wearable robots has transformed them from rigid and cumbersome devices into something we could call exo-suits or exo-musculatures: motorized, lightweight and comfortable clothing-like devices. If one thinks of the ideal soft wearable robot (exoskeleton) as a piece of clothing in which the actuation system is fully integrated into its fabrics, we consider that that existing technologies currently used in the design of these devices do not fully satisfy this premise. Ultimately, these actuation systems are based on conventional technologies such as DC motors or pneumatic actuators, which due to their volume and weight, prevent a seamless integration into the structure of the soft exoskeleton. The aim of this thesis is, therefore, to design of an actuator that represents an alternative to the technologies currently used in the field of soft wearable robotics, after having determined the need for an actuator for soft exoskeletons that is compact, flexible and lightweight, while also being able to produce the force required to move the limbs of a human user. Since conventional actuation technologies do not allow the design of an actuator with the required characteristics, the proposed actuator design has been based on so-called emerging actuation technologies, more specifically, on shape memory alloys (SMA). The mechanical design of the actuator is based on the Bowden transmission system. The SMA wire used as the transducer of the actuator has been routed into a flexible sheath, which, in addition to being easily adaptable to the user's body, increases the actuation bandwidth by reducing the cooling time of the SMA element by 30 %. At its nominal operating regime, the actuator provides an output displacement of 24 mm and generates a force of 64 N. Along with the actuator, a thermomechanical model of its SMA transducer has been developed to simulate its complex behavior. The developed model is a useful tool in the design process of future SMA-based applications, accelerating development ix time and reducing costs. The model shows very few discrepancies with respect to the behavior of a real wire. In addition, the model simulates characteristic phenomena of these alloys such as thermal hysteresis, including internal hysteresis loops and returnpoint memory, the dependence between transformation temperatures and applied force, or the effects of latent heat of transformation on the wire heating and cooling processes. To control the actuator, the use of a non-linear control technique called four-term bilinear proportional-integral-derivative controller (BPID) is proposed. The BPID controller compensates the non-linear behavior of the actuator caused by the thermal hysteresis of the SMA. Compared to the operation of two other implemented controllers, the BPID controller offers a very stable and robust performance, minimizing steady-state errors and without the appearance of limit cycles or other effects associated with the control of these alloys. To demonstrate that the proposed actuator together with the BPID controller are a valid solution for implementing the actuation system of a soft exoskeleton, both developments have been integrated into a real soft hand exoskeleton, designed to provide force assistance to astronauts. In this case, in addition to using the BPID controller to control the position of the actuators, it has been applied to the control of the assistive force provided by the exoskeleton. Through a simple mechanical multiplication mechanism, the actuator generates a linear displacement of 54 mm and a force of 31 N, thus fulfilling the design requirements imposed by the application of the exoskeleton. Regarding the control of the device, the BPID controller is a valid control technique to control both the position and the force of a soft exoskeleton using an actuation system based on the actuator proposed in this thesis.La robótica flexible (soft robotics) ha supuesto un cambio de paradigma en el diseño de robots convencionales; mientras que estos consisten en estructuras monolíticas, hechas de materiales duros y normalmente compuestas de varias articulaciones rígidas, el diseño de los robots flexibles se basa en el uso de materiales deformables como polímeros, fluidos o geles, resultando en un diseño biomimético que replica el comportamiento de los tejidos orgánicos. La introducción de esta filosofía de diseño en el campo de los robots vestibles (wearable robots) ha hecho que estos pasen de ser dispositivos rígidos y pesados a ser algo que podríamos llamar exo-trajes o exo-musculaturas: prendas de vestir motorizadas, ligeras y cómodas. Si se piensa en el robot vestible (exoesqueleto) flexible ideal como una prenda de vestir en la que el sistema de actuación está totalmente integrado en sus tejidos, consideramos que las tecnologías existentes que se utilizan actualmente en el diseño de estos dispositivos no satisfacen plenamente esta premisa. En última instancia, estos sistemas de actuaci on se basan en tecnologías convencionales como los motores de corriente continua o los actuadores neumáticos, que debido a su volumen y peso, hacen imposible una integraci on completa en la estructura del exoesqueleto flexible. El objetivo de esta tesis es, por tanto, el diseño de un actuador que suponga una alternativa a las tecnologias actualmente utilizadas en el campo de los exoesqueletos flexibles, tras haber determinado la necesidad de un actuador para estos dispositivos que sea compacto, flexible y ligero, y que al mismo tiempo sea capaz de producir la fuerza necesaria para mover las extremidades de un usuario humano. Dado que las tecnologías de actuación convencionales no permiten diseñar un actuador de las características necesarias, se ha optado por basar el diseño del actuador propuesto en las llamadas tecnologías de actuación emergentes, en concreto, en las aleaciones con memoria de forma (SMA). El diseño mecánico del actuador está basado en el sistema de transmisión Bowden. El hilo de SMA usado como transductor del actuador se ha introducido en una funda flexible que, además de adaptarse facilmente al cuerpo del usuario, aumenta el ancho de banda de actuación al reducir un 30 % el tiempo de enfriamiento del elemento SMA. En su régimen nominal de operaci on, el actuador proporciona un desplazamiento de salida de 24 mm y genera una fuerza de 64 N. Además del actuador, se ha desarrollado un modelo termomecánico de su transductor SMA que permite simular su complejo comportamiento. El modelo desarrollado es una herramienta útil en el proceso de diseño de futuras aplicaciones basadas en SMA, acelerando el tiempo de desarrollo y reduciendo costes. El modelo muestra muy pocas discrepancias con respecto al comportamiento de un hilo real. Además, es capaz de simular fenómenos característicos de estas aleaciones como la histéresis térmica, incluyendo los bucles internos de histéresis y la memoria de puntos de retorno (return-point memory), la dependencia entre las temperaturas de transformacion y la fuerza aplicada, o los efectos del calor latente de transformación en el calentamiento y el enfriamiento del hilo. Para controlar el actuador, se propone el uso de una t ecnica de control no lineal llamada controlador proporcional-integral-derivativo bilineal de cuatro términos (BPID). El controlador BPID compensa el comportamiento no lineal del actuador causado por la histéresis térmica del SMA. Comparado con el funcionamiento de otros dos controladores implementados, el controlador BPID ofrece un rendimiento muy estable y robusto, minimizando el error de estado estacionario y sin la aparición de ciclos límite u otros efectos asociados al control de estas aleaciones. Para demostrar que el actuador propuesto junto con el controlador BPID son una soluci on válida para implementar el sistema de actuación de un exoesqueleto flexible, se han integrado ambos desarrollos en un exoesqueleto flexible de mano real, diseñado para proporcionar asistencia de fuerza a astronautas. En este caso, además de utilizar el controlador BPID para controlar la posición de los actuadores, se ha aplicado al control de la fuerza proporcionada por el exoesqueleto. Mediante un simple mecanismo de multiplicación mecánica, el actuador genera un desplazamiento lineal de 54 mm y una fuerza de 31 N, cumpliendo así con los requisitos de diseño impuestos por la aplicación del exoesqueleto. Respecto al control del dispositivo, el controlador BPID es una técnica de control válida para controlar tanto la posición como la fuerza de un exoesqueleto flexible que use un sistema de actuación basado en el actuador propuesto en esta tesis.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Fabio Bonsignorio.- Secretario: Concepción Alicia Monje Micharet.- Vocal: Elena García Armad

First Lunar Outpost support study

The First Lunar Outpost (FLO) is the first manned step in the accomplishment of the Space Exploration Initiative, the Vice President's directive to NASA on the 20th anniversary of the Apollo moon landing. FLO's broad objectives are the establishment of a permanent human presence on the moon, supporting the utilization of extraterrestrial resources in a long-term, sustained program. The primary objective is to emplace and validate the first elements of a man tended outpost on the lunar surface to provide the basis for: (1) establishing, maintaining and expanding human activities and influence across the surface; (2) establishing, maintaining and enhancing human safety and productivity; (3) accommodating space transportation operations to and from the surface; (4) accommodating production of scientific information; (5) exploiting in-situ resources. Secondary objectives are: (1) to conduct local, small scale science (including life science); (2) In-situ resource utilization (ISRU) demonstrations; (3) engineering and operations tests; (4) to characterize the local environment; and (5) to explore locally. The current work is part of ongoing research at the Sasakawa International Center for Space Architecture supporting NASA's First Lunar Outpost initiative. Research at SICSA supporting the First Lunar Outpost initiative has been funded through the Space Exploration Initiatives office at Johnson Space Center. The objectives of the current study are to further develop a module concept from an evaluation of volumetric and programmatic requirements, and pursue a high fidelity design of this concept, with the intention of providing a high fidelity design mockup to research planetary design issues and evaluate future design concepts

Investigation of the Interaction Between a Human Index Finger and Spacesuit Glove

With over five decades of spaceflight experience, from the Mercury Program to the current International Space Station, it is well recognized that Extravehicular Activity (EVA), is a critical operational capability necessary for successful space habitation. Whether in LEO or on the Lu-nar and Martian surfaces, an EVA suit must provide life support systems, communication, power, thermal protection and radiation protection. In addition to these functions, the EVA suit must be comfortable and not inhibit the performance of the human. A critical component of the EVA suit are the gloves. Whether it be for exterior assembly, maintenance or science-based surface operations, there will be a continued reliance on manual tasks, requiring fine use of a crew member’s hands. The long duration nature of a Lunar or Martian mission requires spacesuit gloves to be reliable, durable and nearly invisible to the crew-member. While several researchers have studied the effects of EVA Gloves and pressurization on hand strength, dexterity and tactility, these efforts relied on exterior measures of the performance of a glove. Although measures such as grip strength, range of motion and task completion time are valid metrics for how well a glove per-forms, they provide little insight on the mechanics of the human-glove interaction. To engineer the best glove for future LEO, Lunar and Martian EVA missions, it is critical to develop a deeper understanding of the complex interactions that take place inside of the glove. A finite element model of the interaction between the human index finger and notional EVA glove pressure bladder and restraint layer was developed to further understand this interaction. It was found that material modulus was the largest contributing factor (accounting for approximately 72% of overall stiff-ness) followed by bunching of the glove (accounting for approximately 25% of overall stiffness). It was also determined that pressure had minimal effect on the overall stiffness of the EVA glove finger. Additionally it was found that the pre-bunching of the restraint layer significantly reduced the overall stiffness of the glove finger. Finally, it was shown that material modulus and thickness of the restraint layer, material thickness of the pressure bladder and convolute size had the largest effects on glove stiffness