Bio-Sonar and bat-inspired robotic sonar – The acoustic flight room
Bats perceive their world acoustically by emitting sonar calls and analyzing the returning echoes with a sophistication that dramatically outperforms current (human) sonar technology. During the past 50 million years, bats have evolved special emission and reception antennae, a huge variety of sonar signals, and an extraordinary ability to analyze echoes in their brains. Among others, bats can recognize complex objects according to their echoes and they can adjust their sonar parameters within milliseconds according to task, giving them the capacity to pursue and capture erratically moving, miniature prey, even in the presence of dense background acoustic "clutter." Over 1000 species of echolocating bats have evolved optimal, diverse sonar solutions which suit the various foraging strategies they use. For example, bats that search for large insects in open air use different sonar strategies than bats that search for tiny insects in the forest.
A unique acoustic room in the Neuro-ecology lab allows us to study how bats actively control their sonar in perception of the world. Equipped with a large wideband microphone array and a 16-high speed camera system that allows precise tracking of the bat and its ears and wings, this room enables us to accurately reconstruct the bat's bio-sonar beam in real time. Data generated is then shared with our colleagues in the school of mechanical engineering to inform principles of robotic sonar and to create bio-inspired novel technologies. Progress in this area includes the mimicking of the movement of bats' special ears and emission antennae and the development of algorithms for bats' sensory-motor behavior (how sensory input is translated into motor commands).
By recording bat activity in our highly controlled and monitored flight room, we uncover and elucidate the secrets of the bat bio-sonar system, providing insight into the bat's sensory brain that opens pathways for improving human sonar technologies.