The biosonar system of bats has many unique adaptations which allow for navigation in extremely cluttered environments. One such adaptation is the rapid motion of the pinna and noseleaf observed in certain families of old-world bats (Rhinolophidae and Hipposiderae). Little is known about the physical properties about this adaptation affects emitted pulses or incoming echoes. To explore the physical properties of biosonar systems utilizing dynamic peripheries, biomimetic sonar systems have been devised, which can be used to simulate the structural characteristics of the pinna and noseleaf geometry as well as the motor characteristics. Using this method, it was determined that the changing conformations of the biomimetic baffles were responsible for time-variant signatures in echoes. These signatures could be seen in echoes from a variety of both simple and complex target shapes. Then to further the capabilities of the device, an improved actuation system was devised using pneumatic actuation. This allowed for the baffles to make several unique motions as opposed to being restricted to one previously. It was also shown that the distinct motion profiles of the system led to distinct differences in the received acoustic signal. The features encoded by this system could lead to improvements in the development of improved sensing of smaller autonomous systems.
GRANT INFORMATION: This work was supported by grants from the Office of Naval Research (ONR) and the Naval Engineering Education Consortium (NEEC). Additional support was provided by an East Asia and Pacific Summer Institutes (EAPSI) fellowship from the National Science Foundation (NSF). / Doctor of Philosophy / Bats are known for using echolocation in addition to sight for hunting and navigating at night. The capabilities of bats and their ``sonar'' systems vary widely, as each species has evolved to survive in its specific environment. Certain species of bats indigenous to Eurasia are observed to perform complex motions of the outer ear and noseleaf (a ridged structure which sits atop the nostrils and acts like a ``megaphone'' of sorts). These bats are noted to be able to live in particularly cluttered environments and could be a particularly useful model organism for improving sonar. This is because since they are able to acquire detailed information about its surroundings with only their nostrils and ears, are able to outperform complicated man-made devices with thousands more sensing elements. To be able to better understand how a fast-moving ear and noseleaf can improve the sonar capabilities of bats, robots which mimic these bats have been devised, with the main purpose being to replicate the sensing elements of the bat. There have been significant changes made to the robotic sonar head in order to allow for us to expand the capabilities of our research. Using CT-scans as reference, the design of the baffles was redesigned to become more realistic and to have more features observed in the bats. A new method was designed in order to move the ``ears'' and ``noseleaf'' of the robot, using pneumatic actuators, which allowed for better control of the system. Finally, prototype sensors were developed to aid in the development of a motion feedback system to ensure a stable system. The robotic sonar has been used in several experiments to study the effects of a fast-moving, flexible anatomy on the physical properties of echoes. This is first illustrated by studying the echoes from various targets with changes in ear and noseleaf shape. Additionally, with the use of the improved actuation system, it was shown that different motion profiles lead to different responses. The continued development of this system and the changes to the signals explored provide new opportunities for furthering the fields of adaptive sensing as they apply to robots and other platforms. Being able to use a few ``smart'' sensors will help reduce the size, power, and weight costs of traditional sensing designs and allow for more robust and efficient technology to be produced.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/101531 |
| Date | 17 December 2020 |
| Creators | Sutlive, Joseph Vinson |
| Contributors | Graduate School, Mueller, Rolf, Moore, Ignacio T., Leonessa, Alexander, LaConte, Stephen M. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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