Here is another robot inspired by nature that can swim untethered under water. Engineers at the University of California San Diego developed this squid-like robot for underwater exploration. It can carry a sensor, including a camera. The robot carries its power source inside its body.
This robot is made from soft materials such as acrylic polymer in addition to 3D printed and laser cut parts. Here is how it works:
robot takes a volume of water into its body while storing elastic energy in its skin and flexible ribs. It then releases this energy by compressing its body and generates a jet of water to propel itself.
At rest, the squid robot is shaped roughly like a paper lantern, and has flexible ribs, which act like springs, along its sides. The ribs are connected to two circular plates at each end of the robot. One of them is connected to a nozzle that both takes in water and ejects it when the robot’s body contracts. The other plate can carry a water-proof camera or a different type of sensor.