A robotic fish tail and an elegant math ratio could inform design of next-gen underwater drones

Researchers built a fishlike robot that uses a programmable artificial tendon to tune its own tail stiffness while swimming in a water channel. The results were impressive: The robot could swim over a wider range of speeds while using almost half as much energy as the same robot with a fixed-stiffness tail.

source https://www.sciencedaily.com/releases/2021/08/210811162830.htm