Dynamic Sensing Inspired by Bat Biosonar

Research by Rolf Müller

Despite decades of engineering efforts, the biosonar system of bats still remains way ahead of its man-made peers when it comes to navigating structure-rich natural environments. Using biosonar as their primary portal for information on the outside worlds, certain bat species are able to pursue a variety of prey amid dense vegetation. Some of the most sophisticated biosonar systems found in bats have a remarkable dynamics that cannot be found in any engineered sonar or radar system: As the ultrasonic pulses are emitted, the bats use special baffle structures (“noseleaves”) to modulate the distribution of the emitted energy over direction and frequency. Since the noseleaf surfaces can change their shapes while they diffract the outgoing biosonar pulses, a wave packets emitted by the bats are emblazoned with time-variant signatures. Similar dynamic effects can be seen on the reception-side of bat biosonar where the pinnae are changing their shapes through muscular actuation.

Current research in the BIST Center tries to recreate this unusual peripheral dynamics of the bat biosonar system with biomimetic robotic sonar. The goal of these efforts is to understand how dynamic sensing paradigms can be used to encode reliable sensory information on natural environments. These sensors are intended to give man-made systems the same level of autonomy in natural environments that bats have been enjoying for millions of years.

A bat-inspired dynamic sonar head.