2026-09-19T07:58:55Zhttps://ecommons.cornell.edu/server/oai/requestoai:ecommons.cornell.edu:1813/1206522026-05-15T17:54:00Zcom_1813_35col_1813_47
Simmons, Devin
Nunez, Cara
Helbling, Elizabeth
2026-04-02T18:33:34Z
2025-08
ProQuest Submission ID: 12578
ProQuest Publication ID: 32171204
https://hdl.handle.net/1813/120652
https://doi.org/10.7298/ttkp-9p04
17422468
100 pages
Wearable devices used in both research and industry require frequent recharg-ing. Typically, a device must be removed and charged separately, which reduces the device’s overall utility, especially if its primary function is for applications requiring continuous monitoring or actuation. To address this challenge, this work presents a compliant, centimeter-scale energy harvesting system that con- verts stored pneumatic energy via human movement into electricity intended to recharge a battery. The system design uses human footstrikes to pump air into an on-body pneumatic storage pouch. The released air then drives an axial flux induction generator, producing a maximum open circuit voltage of 3.89 Volts (V) and maintaining 2 V for over 38 seconds at a pouch pressure of 19.5 pounds per square inch absolute (psia). The generator’s design is guided by a mathe- matical model derived from Faraday’s Law along with magnetic field simula- tions in Ansys Maxwell. During the design process, emphasis was placed on wearability, form factor minimization, and fabrication using non-specialized, rapid-prototyping techniques. All structural components outside of the mag- nets, ball bearings, and center shaft are fabricated from compliant materials to enhance user comfort and device durability. The system is characterized across a range of pouch pressures and wall supply flowrates where a flowrate of 10 liters per minute (lpm) produced a maximum RMS output power of 34.7 milli- watts (mW) and a RMS voltage of 2.76 V. At this flowrate, the device outputs 12.6 milliamps (mA) which can trickle charge a 1.2 V nickel cadmium (NiCD) or nickel–metal hydride (NiMH) battery. While the generator’s pneumatic to electric power efficiency is approximately 0.73%, the current prototype’s out- put power, simplified fabrication techniques, and wearability demonstrate the feasibility of this system as a self-contained, human-powered, passive energy solution for low-power wearable electronics.
2026-03-09
en
Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/
Designing a Wearable, Centimeter-Scale Generator Powered by Human Movement
dissertation or thesis
application/pdf
Mechanical Engineering
Cornell University
Master of Science
M.S., Mechanical Engineering
https://hdl.handle.net/1813/59810.2
Publication
Cornell Theses and Dissertations
Simmons, Devin
5893a6ea-7af3-41d7-abc6-04bcd26ab5df
open.access
open.access
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<Abstract>Wearable devices used in both research and industry require frequent recharg-ing. Typically, a device must be removed and charged separately, which reduces the device’s overall utility, especially if its primary function is for applications requiring continuous monitoring or actuation. To address this challenge, this work presents a compliant, centimeter-scale energy harvesting system that con- verts stored pneumatic energy via human movement into electricity intended to recharge a battery. The system design uses human footstrikes to pump air into an on-body pneumatic storage pouch. The released air then drives an axial flux induction generator, producing a maximum open circuit voltage of 3.89 Volts (V) and maintaining 2 V for over 38 seconds at a pouch pressure of 19.5 pounds per square inch absolute (psia). The generator’s design is guided by a mathe- matical model derived from Faraday’s Law along with magnetic field simula- tions in Ansys Maxwell. During the design process, emphasis was placed on wearability, form factor minimization, and fabrication using non-specialized, rapid-prototyping techniques. All structural components outside of the mag- nets, ball bearings, and center shaft are fabricated from compliant materials to enhance user comfort and device durability. The system is characterized across a range of pouch pressures and wall supply flowrates where a flowrate of 10 liters per minute (lpm) produced a maximum RMS output power of 34.7 milli- watts (mW) and a RMS voltage of 2.76 V. At this flowrate, the device outputs 12.6 milliamps (mA) which can trickle charge a 1.2 V nickel cadmium (NiCD) or nickel–metal hydride (NiMH) battery. While the generator’s pneumatic to electric power efficiency is approximately 0.73%, the current prototype’s out- put power, simplified fabrication techniques, and wearability demonstrate the feasibility of this system as a self-contained, human-powered, passive energy solution for low-power wearable electronics.</Abstract>
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