During the daily activities, such as chewing, eating, speaking, etc., the human jaw moves and the earcanal is deformed by its anatomic neighbor called the Temporomandibular Joint (TMJ). Given the frequency of those jaw-joint activities, the earcanal dynamic movement is a promising source of energy at close vincinity of the ear, and such envery can be harvest by using a mechanical-electrical transducer, dubbed energy harvester. Yet, the optimal design of such micromachine requires to characterize the TMJ’s range of motion, its mechanical action on the earcanal and its mechanical power capability. For that purpose, this research presents two methods to analyse the earcanal dynamic movements: first, an in-situ approach based on measuring the pressure variation in a water-filled earplug fitted inside the earcanal; and second, an anatomic-driven mechanism in the form of a chewing test fixture capable to reproduce the TMJ kinematics with great precision. The pressure earplug system provides the earcanal global dynamics which can be derived as an equivalent displaced volume while the chewing test fixture provides the discrete displacement along the earcanal wall. Both approaches are complementary and contribute to a better analysis of the interaction between TMJ and earcanal. Ultimately, the knowledge of the maximum displacement area and the derived generated power within the earcanal will lead to the design of a micromachine allowing to further investigate in-ear energy harvesting strategies.
In-Ear Energy Harvesting: Source Characterization and Mechanical Simulator (Part I)
Published: 14 April 2021 by MDPI in Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021) session Micromachines for scientific research
Keywords: TMJ; earcanal dynamic motion; anatomic coupling; power capability