Real-Time Sound Source Localization in Robots Using Fly <i>Ormia Ochracea</i> Inspired MEMS Directional Microphone

Abstract

Sound localization is an integral part of robots for safe interaction with the environment. However, the constraints like high computational time, multiple microphones, and low accuracy require the researcher to focus on innovative solutions. Herein, we have presented a unique and easy-to-implement approach for sound source localization (SSL) by taking the advantage of the “figure-of-eight” response of the fly-inspired MEMS directional microphone (DM). The complete SSL task is performed using a single microphone. Initially, the servo motor-controlled rotational stage comprising DM is placed at an angle where the DM has a maximum response. Afterward, the system performs lateralization based on the intensity information. This step narrows down the search from 360 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> to 90 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> with some ambiguities. Finally, for localization, the system tracks the “figure-of-eight” response by calculating the intensity differences and stops the servo motor when the maximum response position of DM faces the sound. For better visualization, the system is also equipped with a laser diode to pinpoint the sound source. The results indicate that the system is capable of localizing the sound with an accuracy of nearly <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm 5^{\circ }$</tex-math></inline-formula> . The proposed system opens a path for SSL in several situations, particularly in human–robot interactions using a single microphone with less complexity and high accuracy.