Aerospace engineering professor Derek Paley thinks underwater robots could take a tip or two from other swimmers that have been around a bit longer: fish. Drawing inspiration from the remarkable synchrony of movement displayed by schools of fish, the University of Maryland researcher has been looking to apply their keys to success to their inorganic counterparts. His efforts recently culminated in the completion of a robotic submarine that is strikingly similar both in appearance and dynamics to living fish.
Sensory Imitation
One essential driver of the incredible responsiveness of fish to changes in their surroundings is their lateral line system, a kind of neuro-circuitry that appears as a physical line down the side of many fish species.It allows them to rapidly sense changes in water movement that can indicate many important variables. For instance, if a predator is lurking in their vicinity but outside their immediate field of vision, many fish are able to literally feel the movement of the threat nearby.
Paley’s robot comes equipped with sensor nodes that closely mirror the lateral line system. This setup allows the fish-bot to quickly detect and react to changes in similar fashion to living fish.
Propulsion
Motion was the second major area in which Paley sought to improve underwater autonomous vehicles through nature-inspired changes. Fish, of course, propel themselves by sweeping their tails in a side-to-side motion known as undulation. Their locomotive grace inspired Paley’s robot,which features a motor attached to a momentum wheel. When the wheel moves in one direction, the “tail” of the submersible moves the opposite way, establishing a repeating kinetic loop that pushes it forward more effectively than a propeller. It also creates less hydrodynamic disturbance as it moves through the water than traditional methods of propulsion, which could contribute to its usefulness as a means of studying natural habitats.
Water Collection, Ecological Observation…and Military Defense?
The potential applications for a fleet of these fish-inspired robots are wide-ranging. Paley sees an immediate use in collecting water samples in estuaries like the Chesapeake Bay. The robots could help monitor water quality in at-risk environments without disrupting the ecology. The stealth of the machines, however, is such that there’s also the possibility of more ambitious usage in the future. It’s not hard to imagine a school of robo-fish patrolling strategic marine locations like ports incognito.
To learn about another case of animals inspiring robotics, check out this article on Boston Dynamics’ dog-based robot.