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Human-powered inertial energy harvesters: the effect of orientation, location and activity on the obtainable electrical power

Human-powered inertial energy harvesters: the effect of orientation, location and activity on the obtainable electrical power
Human-powered inertial energy harvesters: the effect of orientation, location and activity on the obtainable electrical power
Human-powered inertial energy harvesting is an emerging technology that can power electronic devices using electrical energy scavenged from human motion. Traditional energy harvesters generate energy only from a single axis, and are referred to one degree-of-freedom (1-DOF) energy harvesters. In this thesis, a two degree-of-freedom (2-DOF) energy harvester consisting of two orthogonal 1-DOF energy harvesters is studied. This research theoretically and experimentally investigates the effect of orientation, location and activity on the obtainable power from 2-DOF human-powered inertial energy harvesters.

An on-body measurement study has been conducted to collect acceleration data from five key locations on the body during both walking and running. The collected data have been analyzed to evaluate the harvestable power along different orientations of both 1-DOF and 2-DOF inertial energy harvesters. The results show that the orientation of 1-DOF generators on the body greatly affects the output power. 2-DOF generators can maintain a more constant power output with rotation, thus are more reliable than 1-DOF generators. For 1-DOF generators, and for each location and activity, only 6% of the tested orientations harvest over 90% of the maximum power. For 2-DOF generators, this is increased to 32%, showing a considerable improvement.

To validate the analytical results, 1-DOF mechanical- and magnetic-spring electromagnetic generators have been designed and prototyped. A novel design has been proposed to linearise magnetic springs for low frequency use. Experimental validation shows that the design exhibits a linearity of 2% across a ±25 mm displacement range, presenting a significant improvement over the state-of-the-art. A 2-DOF inertial generator that consists of two orthogonal 1-DOF mechanical-spring generators has been tested at three locations around the knee while running. At each location, the 2-DOF generator has been rotated to four different angles. The results show that 2-DOF generators can generate over 81% of the maximum power in all orientations. For 1-DOF generators, it is only 35%.
Huang, Hui
ae101bbc-d3d7-4bbd-a3ac-55ee4c0f8118
Huang, Hui
ae101bbc-d3d7-4bbd-a3ac-55ee4c0f8118
Merrett, Geoffrey
89b3a696-41de-44c3-89aa-b0aa29f54020

Huang, Hui (2014) Human-powered inertial energy harvesters: the effect of orientation, location and activity on the obtainable electrical power. University of Southampton, School of Electronics and Computer Science, Doctoral Thesis, 180pp.

Record type: Thesis (Doctoral)

Abstract

Human-powered inertial energy harvesting is an emerging technology that can power electronic devices using electrical energy scavenged from human motion. Traditional energy harvesters generate energy only from a single axis, and are referred to one degree-of-freedom (1-DOF) energy harvesters. In this thesis, a two degree-of-freedom (2-DOF) energy harvester consisting of two orthogonal 1-DOF energy harvesters is studied. This research theoretically and experimentally investigates the effect of orientation, location and activity on the obtainable power from 2-DOF human-powered inertial energy harvesters.

An on-body measurement study has been conducted to collect acceleration data from five key locations on the body during both walking and running. The collected data have been analyzed to evaluate the harvestable power along different orientations of both 1-DOF and 2-DOF inertial energy harvesters. The results show that the orientation of 1-DOF generators on the body greatly affects the output power. 2-DOF generators can maintain a more constant power output with rotation, thus are more reliable than 1-DOF generators. For 1-DOF generators, and for each location and activity, only 6% of the tested orientations harvest over 90% of the maximum power. For 2-DOF generators, this is increased to 32%, showing a considerable improvement.

To validate the analytical results, 1-DOF mechanical- and magnetic-spring electromagnetic generators have been designed and prototyped. A novel design has been proposed to linearise magnetic springs for low frequency use. Experimental validation shows that the design exhibits a linearity of 2% across a ±25 mm displacement range, presenting a significant improvement over the state-of-the-art. A 2-DOF inertial generator that consists of two orthogonal 1-DOF mechanical-spring generators has been tested at three locations around the knee while running. At each location, the 2-DOF generator has been rotated to four different angles. The results show that 2-DOF generators can generate over 81% of the maximum power in all orientations. For 1-DOF generators, it is only 35%.

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Published date: March 2014
Organisations: University of Southampton, Electronic & Software Systems

Identifiers

Local EPrints ID: 364251
URI: http://eprints.soton.ac.uk/id/eprint/364251
PURE UUID: 3f888597-01d3-495b-b93c-9b072a7fbd42
ORCID for Geoffrey Merrett: ORCID iD orcid.org/0000-0003-4980-3894

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Date deposited: 29 May 2014 11:39
Last modified: 06 Jun 2018 12:42

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