Optimisation de la géométrie d'un dispositif de micrograpillage énergétique intra-auriculaire

Abstract

The economic costs and environmental impacts associated with the use of batteries to power in-ear devices are substantial. Studies have demonstrated that energy generated by earcanal deformation during jaw movement can be converted to electrical energy. Harvesting biomechanical energy to power in-ear devices could be an alternative to batteries. The goal of this master’s in applied sciences was to design an in-ear energy harvesting device, first by identifying the type of earcanal deformation that would yield the maximum amount of mechanical energy convertible to electrical energy and second by selecting the best type of piezoelectric material and its optimal positioning within the ear. A literature review was conducted on three topics : current techniques used to power hearing-aids, parameters relevant to the analysis of earcanal deformation and current methods of distortion analysis of deformable solids. A calculation method was used to model the mechanical behavior of a custom earplug during earcanal deformation. Point clouds obtained by white light 3D scanning of custom earmolds in “open mouth” and “closed-mouth” positions were used to quantify bending and compression energies and the model was validated using 12 human subjects. The theoretical model for the energy conversion was experimentally validated using custom earplug prototypes fitted with a thin film of piezopolymer. The mechanical behavior of this prototype was modeled and the theoretical predications were compared with the experimental results. The bending energy is on average three times higher than the radial compression energy. The in-ear prototype design to harvest the bending energy model predicts the open circuit voltage induced by earcanal deformation. It was valued at 4.1V. Experimentally measured voltage was sufficient at 4.5V. In the future, an energy conversion device as presented in this study could be used to supply energy to in-ear devices. These results can also be used to design earcanal deformation sensors, or any type of curved energy harvester made with a thin film of piezoelectric polymer. These findings will be used to design a future in-ear energy harvester device, which could revolutionize the market of wearables and hearing aids by supplementing or replacing batteries.

Date	22 Nov 2016
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Jérémie Voix (Supervisor) & Ricardo J. Zednik (Co-supervisor)