Blind as a Bat: Audible Echolocation on Small Robots

Frederike Dümbgen
Postdoc
University of Toronto, Canada
Lab webpage: http://asrl.utias.utoronto.ca/

Abstract
For safe and efficient operation, mobile robots need to perceive their environment, and in particular, perform tasks such as obstacle detection, localization, and mapping.
Although robots are often equipped with microphones and speakers, the audio modality is rarely used for these tasks. Compared to the localization of sound sources, for which many practical solutions exist, algorithms for active echolocation are less developed and often rely on hardware requirements that are out of reach for small robots.

We propose an end-to-end pipeline for sound-based localization and mapping that is targeted at, but not limited to, robots equipped with only simple buzzers and low-end microphones.
The method is model-based, runs in real time, and requires no prior calibration or training.
We successfully test the algorithm on the e-puck robot with its integrated audio hardware, and on the Crazyflie drone, for which we design a reproducible audio extension deck. We achieve centimeter-level wall localization on both platforms when the robots are static during the measurement process. Even in the more challenging setting of a flying drone, we can successfully localize walls, which we demonstrate in a proof-of-concept multi-wall localization and mapping demo.

Bio
Frederike Dümbgen is currently a postdoctoral researcher at the Robotics Institute of University of Toronto, working with Prof. Tim Barfoot in the Autonomous Space Robotics Lab. She received her PhD with thesis entitled “Blind as a bat: spatial perception without sight” in November 2021, under the advisors Prof. Martin Vetterli and Dr. Adam Scholefield from the Laboratory of AudioVisual Communications (LCAV) in Computer Science at École Polytechnique Fédérale de Lausanne (EPFL), Switzerland. Before that, she obtained her B.Sc. and M.Sc. in Mechanical Engineering from EPFL in 2013 and 2016, respectively, with a minor in Computational Science and Engineering, and Master’s thesis at the Autonomous Systems Lab of ETH Zürich.
Her research has ranged from novel localization methods, in particular acoustic, radio-frequency and ultra-wideband localization, to, most recently, globally optimal methods for robotics.