Marines can fight in the air, on the ground and at sea – and soon they'll have a robot that can tag along for at least two of those. Pliant Energy Systems' Velox robot can track you on both land and sea. Snow, sand, ice, mud, it doesn't matter the terrain; the Velox can follow you anywhere. But its true "natural" habitat is underwater, where its undulating propulsion system and efficient electrical drive can keep up with any target.

Its official designation is the Agile Amphibious Swimmer, and it first appeared at the 2017 Naval Future Force Science and Technology Expo in Washington, D.C. What's special about it is that its undersea mode is not driven by the usual propeller system, but rather a pair of versatile, undulating fins that glide through the water, acting as both thrust and guidance systems.

What's amazing is how the robot performs when it makes an amphibious landing, moving just as mobile on difficult terrain as it does in the water.

To the Brooklyn-based designers of Pliant Energy Systems, the smoothly undulating fins are a step far ahead of current, propeller-based systems. Undulating drives mean a lower environmental impact and a lower rate of entanglement in aquatic plants and animals. The fins create movement underwater in much the same way that manta rays do while crawling over land like a snake. This is its biggest selling point to the Office of Naval Research: it can handle any terrain during a single mission.

"The robot's swimming performance alone is unprecedented outside of the natural world," claimed Benjamin Pietro Filardo, founder, CEO, and CTO of Pliant. "But that's only half the story because it can deploy its swimming fins to travel over various land topographies in ways that don't seem to have been explored yet in the field of terrestrial robotics."

The robot's biomimic propulsion is just the beginning. Future versions of the robot could feature a propulsion system that can recharge itself in wind and in waters at sea. The secret is in the substance that makes up the robot's fins, electroactive polymers. As it expands and contracts, it generates electricity. When an electrical current is applied to the material, the material moves, much like biological muscles.

In the future, Pliant looks to create electrical generators powered by the movement of water in waves, rivers, and streams from the same materials that power the Velox drone (like in the video above).