Teams of robot lobsters may someday scour land and sea, using their artificial snouts to root out mines in places humans would rather avoid. At least this is the goal of a team studying the lobster — a creature considered a paragon of odor analysis — in order to create a robotic version of the lobster’s snout Many objects emit odors that are transported by chemical plumes downstream or downwind. Mass-produced mines are no exception. A side effect of the mass production of mines is that they leak TNT, which has an odor that humans can’t smell but lobsters can. The study used the Caribbean spiny lobster as its guinea pig. The lobster has two olfactory antennas — 2-inch-long antennae covered with odor-sensitive hairs — that can sniff out food, friend or enemies. Getting the lobster to perform the necessary task (sit and sniff) was difficult because as one may imagine, an animal as rudimentary as the lobster, is a bit difficult to train. To avoid this problem, the researchers discarded the live lobster in favor of a recently shed lobster exoskeleton, which they filled with epoxy to weigh it down in a tank of water. One of the lobster’s antennas was replaced with a computer-controlled steel wire, and then a real antennas was slipped onto the wire before each experimental trial. The antennas is slipped over the wire, and then a computer was programmed to flick the antennas in the same way as the real ones do. Each flick of the antennas is equivalent to one lobster sniff. The lobster was then submerged in a tank of water and the team released a fluorescent dye into the tank to act as the odor plume. As the plume flowed downstream toward the lobster, the robotic antennas was flicked through the water at the same speed that a real lobster would move it — about 100 milliseconds for the fast down stroke and 300 milliseconds for the slower upstroke, with a 400 millisecond pause between each flick A lobster sniff begins with a rapid down stroke that turns the antennas into a sieve, allowing water to flow between its hairs, while capturing molecules from the plume. Then on the upward stroke, the antennas acts more like a paddle — the water flows around it, leaving intact the pattern of dye or odor molecules picked up during the down stroke. Retaining the odor molecules gives the lobster time to work out what is producing the scent and where it is. As the lobster repeats the flick, the samples of dye previously trapped are washed out, resetting the lobster’s snout between each sniff so it can move on to a new spot and do further odor analysis.
Source:Robo Sniffer