SoFi robotic fish unobtrusively observing and diving into the coral reefs

March 28, 2018, 8:43 a.m. By: Vishakha Jha

SoFi robotic fish

Certain animals are affected by the presence of other elements in their surrounding and rest stay unaffected. Well, human involvement has its own set of causatum on Aquatic life. Have you ever thought what if we humans could get an insight of aquatic life without actually affecting their behaviour?

The scientist of MIT made this possible for all the curious minds out there who want to know or study what goes below the water level. Recently a paper published in Science Robotics the section states that a new kind of soft robotic spy fish has been developed at MIT’s Computer Science and Artificial Intelligence Laboratory that has the ability to camouflage with the marine life i.e. everything living on a coral reef. It is designed to look realistic and can autonomously swim apace with the real fish in the ocean. Once the developers were satisfied with the product they tested it under several conditions. One of the prime locations was Fiji that offered a wide variety of coral environment and providing real-world conditions. SoFi was tested for six dives over three days and consumed almost 240 minutes. It even swam at depth of over 50ft for 40minutes straight without scaring nearby fishes and captured high-resolution photos and videos. Due to its unique feature of balancing its buoyancy and undulating tail, it can swim in a straight line, dive in different directions and turn. The team has also developed Super Nintendo controller and acoustic system which allows them to change their speed and state of motion.

SoFi is handled by a waterproofed game controller that is controlled by a diver which communicates ultrasonically and has the ability to convert high-level direction based command into 3D trajectories. It supports a battery life of 40 minutes which gives ample amount of time to capture and explore the environment.

SoFi robotic fish

The existing AUVs are bulky and not so efficient whereas SoFi has a lightweight setup that comes with a motor, camera and lithium polymer battery similar to one found in our smartphones. The entire back half portion of fish is made by the elements of flexible plastic and silicon rubber and other are formed by a variety of 3-D printed parts which includes the head that holds the major electronics. To eliminate the chances of water leakage into machinery the head is inflated with some amount of baby oil as it will avoid the compression that may be caused due to pressure change.

To help the SoFi swim the water is pumped into balloon-like chambers present in the fishtails through motor pumps which acts as a set of pistons in an engine. It is able to mimic the movement of fish because of the alternating action produced which enables a side by side motion. Primary propulsion starts with the tail that lies between the range of 0.9 and 1.4 Hertz which causes the alternating action by the process according to which one chamber expands, bends and flexes to one side and then actuator comes into action for pushing the water to the other channel which follows a similar process. And the change in flow patterns leads to a wide range of swimming speed with an average speed of about half a body length per second.

A robot like this can help explore the reef more closely than current robots, both because it can get closer more safely to the reef and because it can be better accepted by the marine species. SoFi, as it seems, is just the start towards entering into a wider aspect of marine life. Though it's just the beginning, researchers still need to figure out the impact of a robotic fish on the real world. The Later improvement is expected to deal with speed-related aspect by enhancing the ability of pump system. They have been planning to incorporate the onboard camera to enable SoFi to automatically follow the real-fish. Eventually, the researchers have planned to incorporate entire schools of SoFis collaborating to study underwater ecosystems to enable some underwater autonomy.

A Robotic Fish Swims in the Ocean

Source: MIT News