Researchers at Northwestern University have created a robotic fish that can move from swimming forward and backward to swimming vertically almost instantaneously by using a sophisticated, ribbon-like fin.
The robot -- created after observing and creating computer simulations of the black ghost knifefish -- could pave the way for nimble robots that could perform underwater recovery operations or long-term monitoring of coral reefs.
Led by Malcolm MacIver, associate professor of mechanical and biomedical engineering at Northwestern's McCormick School of Engineering and Applied Science, the team's results are published in the Journal of the Royal Society Interface.
The black ghost knifefish, which works at night in rivers of the Amazon basin, hunts for prey using a weak electric field around its entire body and moves both forward and backward using a ribbon-like fin on the underside of its body.
MacIver, a robotics expert who served as a scientific consultant for "Tron: Legacy" and is science advisor for the television series "Caprica," has studied the knifefish for years. Working with Neelesh Patankar, associate professor of mechanical engineering and co-author of the paper, he has created mechanical models of the fish in hopes of better understanding how the nervous system sends messages throughout the body to make it move.
Planning for the robot -- called GhostBot -- began when graduate student Oscar Curet, a co-author of the paper, observed a knifefish suddenly moving vertically in a tank in MacIver's lab.
"We had only tracked it horizontally before," said MacIver, a recent recipient of the prestigious Presidential Early Career Award for Scientists and Engineers. "We thought, 'How could it be doing this?'"
Further observations revealed that while the fish only uses one traveling wave along the fin during horizontal motion (forward or backward depending on the direction on the wave), while
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