Meeting Abstract
6.1 Saturday, Jan. 4 08:00 Distributed pressure detectors for underwater robotic locomotion and sensing: insight from direct measurements in swimming trout AKANYETI, O.*; YANAGITSURU, Y.R.; LIAO, J.C.; Whitney Laboratory for Marine Bioscience, University of Florida; University of California, San Diego; Whitney Laboratory for Marine Bioscience, University of Florida otarakanyeti@yahoo.com
Arrays of bio-inspired pressure sensors offer unique sensing capabilities in underwater applications by detecting local pressures around moving platforms such as robots. Two fundamental sensing schemes are: 1) to detect a robot’s own motions and provide feedback signals to maintain a desired motion course, and 2) to detect relevant events in the surrounding environment. However, these two sensing schemes are mutually exclusive, given that sensitivity to self-motion typically compromises the ability to sense environmental stimuli. Here we demonstrate that both benefits can be realized by analysing pressure signals from different sensor array subsets. We employed miniature sensors and high-speed video to directly measure the pressure profiles on a freely swimming rainbow trout (Oncorhynchus mykiss, n = 6 fish). We were able to detect when the fish rolled, pitched, yawed or changed its depth, by analysing absolute pressure measurements. During steady swimming, the frequency of the sinusoidal pressure differentials between the sensors across the head matched the tail beat frequency. The amplitude of the pressure differentials was around ~20 Pa at swimming velocity of 3 L s-1. We found that it was possible to filter out self-generated pressures and accurately detect external events simply by analysing pressure differentials instead of absolute pressure measurements. In addition, during steady swimming pressure differentials on the same side of the head were five times smaller than those across the head. Our findings show how the efficient and robust mechanisms of distributed pressure sensing in biological systems can inspire the design of underwater autonomous robots.
