Analysis and design of a sprung rotational energy harvester for wrist-worn wearables subject to a range of low frequency excitations

Master thesis (2023)

Authors

S.J. van den Oever Mechanical Engineering

Contributors

W.W.P.J. van de Sande Mechatronic Systems Design - Mechanical, Maritime and Materials Engineering (supervisor 1)
J.L. Herder Precision and Microsystems Engineering (supervisor 2)
G. Radaelli Mechatronic Systems Design - Mechanical, Maritime and Materials Engineering (supervisor 2)
Faculty
Mechanical Engineering
Copyright: © 2023 Sam van den Oever
Wearables Compliant Mechanisms Sprung Rotational Energy Harvesting Watches
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Published Date

11-05-2023

Language

English

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Faculty

Mechanical Engineering

Abstract

A growing energy demand has sparked interest into harvesting energy from the human body. Often, a rotational proof mass is used to harness energy for a wearable from kinetic motion of its user. The addition of a spring has the potential to significantly increase efficiency for these low-power rotational energy harvesters. In this research a system characterisation is performed from which a dimensionless ratio is formulated to determine optimal spring stiffness for maximisation of average power output as a function of harvester design parameters and excitation inputs. Creating a system that is optimized for the entirety of its operational range rather than for one specific excitation input. Implementation is investigated in the field of horology, where rotational energy harvesters are widely implemented. To increase harvesting efficiency of existing rotational energy harvesters without requiring significant design alterations a compliant design is proposed, prototyped and tested.