Watch a Snake Robot Go for a Swim

When sea snakes swim, they wind their way through the water by flicking their flattened tails, which is super graceful but requires a whole lot of coordination. So when roboticists at Carnegie Mellon University decided that it was time for their landlubbing robot snake to take to the water, they took a shortcut. They approximated the wildly complex biomechanics of a serpent--and then loaded the machine with propellers. The result is a sort of wiggling torpedo, sans warhead: the Hardened Underwater Modular Robot Snake. As you can see in the video below, it manages some impressive swimming by combining an aft thruster to produce forward movement with lateral thrusters along its body for stability control, plus it uses some bending joints (actuators, in the parlance) to position the lateral thrusters.