Design and implementation of a simple and low cost hand for prosthetic applications

Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.The main goal for this work is to develop a body-powered prosthetic hand destined for an 8-year old boy with a congenital hand disorder. The fingers on his right hand are missing but the wrist movement had maintained. Advancements in computer-aided design and additive manufacturing have opened new possibilities of designing and manufacturing prosthetic hands and other assistive devices at very low cost. People from recently formed community e-Nable Group started to use those advancements in order to design and deliver the prosthetic hand devices free of charge for anyone in need. The concept behind these hands is that no actuator is incorporated. The movement of the fingers is based on the movement of the wrist or the elbow. This makes the hands low cost, light-weight, and simple to control, the considerable features for the child prosthetic. So, the methodology for the present study is to use the e-Nable concept and create a hand that clearly outperforms the state of the art e-Nable hands in terms of grasping. This dissertation starts with an overview about the currently existing upper-limb prosthetic devices and their categorization by their working principle. Then it shows a way that was passed from the conception up to the final version of the developed device identifying the problems that were faced in a process and solutions that were found for them. The idea of introducing fingers with compliant joint is also explained. Despite many advantages of compliant digits, their disadvantage is undesired lateral deflections. The way how this problem is addressed is shown in the end of this work. Finally, there is an overview of all the achievements along with some future plans for further investigation. Keywords Prosthetics, Body-powered, 3D Printing, e-Nabled, Complian