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

Objective analysis for evaluation the stress of the hand

The hand is constantly in contact with products and therefore stressed differently. Heavy stress is the cause of unpleasant sensation and can lead to common hand diseases in the worst case. The chapter starts with the description of hand diseases and with methods to determination of hand stress. Subsequently, the chapter is continued with a literature review of hand stress analysis refer to objectively methods. In the main part, two objective methods are developed and presented to analyze the hand stress. These methods allow the simulation and the measurement of hand stress. Compared to the classical approach, the results of the objective methods show a higher accuracy in faster review of hand stress. Finally, the chapter ends with a discussion of the results and gives opportunities to improve the hand model and the measurement system

DESIGN AND ANALYSIS OF A 3D-PRINTED, THERMOPLASTIC ELASTOMER (TPE) SPRING ELEMENT FOR USE IN CORRECTIVE HAND ORTHOTICS

This thesis proposes an algorithm that determine the geometry of 3D-printed, custom-designed spring element bands made of thermoplastic elastomer (TPE) for use in a wearable orthotic device to aid in the physical therapy of a human hand exhibiting spasticity after stroke. Each finger of the hand is modeled as a mechanical system consisting of a triple-rod pendulum with nonlinear stiffness at each joint and forces applied at the attachment point of each flexor muscle. The system is assumed quasi-static, which leads to a torque balance between the flexor tendons in the hand, joint stiffness and the design force applied to the fingertip by the 3D-printed spring element. To better understand material properties of the spring element’s material, several tests are performed on TPE specimens printed with different infill geometries, including tensile tests and cyclic loading tests. The data and stress-strain curves for each geometry type are presented, which yield a nonlinear relationship between stress and strain as well as apparent hysteresis. Polynomial curves are used to fit the data, which allows for the band geometry to be designed. A hypothetical hand is presented along with how input measurements might be taken for the algorithm. The inputs are entered into the algorithm, and the geometry of the bands for each finger are generated. Results are discussed, and future work is noted, providing a means for the design of a customized orthotic device