DTA

Digital Theses Archive

 

Tesi etd-07102017-114422

Type of thesis
Dottorato
Author
BASSANI, GIULIA
URN
etd-07102017-114422
Title
Wearable energy harvesting for motion tracking and health assessment
Scientific disciplinary sector
ING-INF/06
Course
INGEGNERIA - Ph.D. Programme in Emerging Digital Technologies (EDT)
Committee
relatore RUFFALDI, EMANUELE
Membro FONTANA, MARCO
Membro CHRYSANTHOU, YIORGOS
Relatore FRISOLI, ANTONIO
Keywords
  • Nessuna parola chiave trovata
Exam session start date
;
Availability
completa
Abstract
The Internet of Things (IoT) concept is an emerging field that will have impact on several aspects of everyday-life and behavior of potential users. It provides the possibility of motion and healthcare monitoring using Wearable Wireless Body Area Networks (WWBAN) integrated into a telemedicine system. A WWBAN includes a great variety of components that must be integrated following some strict criteria. Power is perhaps the most limiting factor in mobile and wearable technology, thus this work deals with energy harvesting technologies that have the potentials to ideally make the device energy autonomous. <br>First, an in depth research on the state of art of the energy sources both in the environment and on the human body has been performed and kinetic human energy sources has been selected as the best choice for its high versatility and ubiquitous presence. Walking, as a routine activity, has a great potential for biomedical energy harvesting and other than center of mass motion, heel strikes, shoulder and elbow joint motion during arm swings, and leg motions, i.e., ankle, knee, and hip motions are suitable targets for energy harvesting. The heel strikes is the most investigated human body location for energy harvesting purpose. Therefore, this research focus on the mechanical energy available from the flexion-extension of the knees and from the differential forces between human and backpack that have been proved to have significant power outputs. However, the energy harvesting systems already developed still have several limitations. There is an impelling need of a new technology to harvest biomechanical energy without creating discomfort to the users. To this end, EAPs are light and flexible materials that could fulfil this task, and among them the Macro-Fiber Composite (MFC) and Dielectric Elastomers (DEs) stand out for their characteristics. <br>In the first work, thanks to a mechanical framework specifically designed to reproduce the kinematic of a knee joint and actuated using recorded human motion patterns, the feasibility of the non-resonant employment of the MFC to scavenge energy from the various human body movements has been demonstrated. Both the energy of periodic and aperiodic motions can be harvested. The electrical characteristics of the whole system focusing on the Maximum Power Point (MPP) of the MFC have been investigated to optimize the system power output. <br>In the second work, aiming at developing an energy harvesting system with higher power outputs, a DEG have been designed, fabricated, and characterized to effectively harvest the mechanical energy available in the backpack straps during walking. To this end, a backpack has been instrumented with different sensors to prove that the stretches are high enough to be harvested and a comparison between different possible DEG configurations have been performed with the purpose of maximizing the stretch the DEG is submitted to for equal mechanical input. In this task auxetic structures have been proved to significantly increase the DEG performance. A final theoretical evaluation showed the energy outputs achieved with this system.<br>
Files