By Urvashi Chitnavis
Despite all the technological advancements in recent years, it remains a challenging task to document marine life up close. Pieces of engineering created to study these animals tend to either scare away or attract the fish, as do scuba-divers, thereby causing them to deviate from their natural behaviour. But researchers at the Massachusetts Institute of Technology might just have found a solution to this problem.
SoFi: the new tool
On Wednesday, the 21st of March, a team from MITs Computer Science and Artificial Intelligence Lab (CSAIL) released a paper in the journal Science Robotics, describing their latest invention, a new tool for studying ocean life. They call it SoFi, short for Soft Robotic Fish. SoFi might look and behave a lot like a fish, but it consists entirely of electronics. There have been oceanic robots created to observe underwater life before, so what makes this special? SoFi is part of a larger project by CSAIL, focussed on soft robots.
How will soft robots benefit us?
Soft robots have been found to have several advantages over their hard-bodied counterparts, in that they can move more nimbly and efficiently. In fact, MIT researchers say this robotic fish can execute a quick escape manoeuvre with a speed in the order of a 100 milliseconds, identical to that of a biological fish! The soft-bodied robot is also sturdier, such that it can not only survive collisions better but can also provide information about the collision, in order to form a more efficient motion plan. Now, thats an intelligent piece of machinery.
What makes SoFi so useful in observing marine life, is that he is inconspicuous. Blending into the surroundings means that the robot can capture rare footage of marine life that was earlier off-limits. And how better to blend in with fish than to look like a fish yourself? Funnily enough, the head of this robot uses a fisheye lens to take high-resolution videos and photographs. Its body is made of a silicone elastomer, and several parts are 3D-printed, making it relatively inexpensive to manufacture. The fish moves by gently undulating its tail, much like a real fish. This wiggling motion is achieved by cycling water back and forth between two chambers present in the tail, producing the characteristic side-to-side movement.
Overcoming major challenges
One of the major challenges encountered by the SoFi team was a large amount of energy expended in adjusting the depth of the robot. To solve this, they once again drew inspiration from the biological fish and used a cylinder filled with air, much like the swim bladder in a fish, which is compressed and decompressed to adjust the buoyancy of the robot, allowing it to float at different depths.
Another major challenge encountered while engineering underwater robots is communication. This is because radio waves only travel a few centimetres in water effectively. To overcome this, SoFi turns to sound. Divers can control this fish with acoustic signals via a remote module. But the long-term goal is what makes this a truly exciting creation. It is hoped that one day, these robots will use machine vision to lock onto a fish to be studied and swim around with it. The vision is to create a network of robotic fish that can patrol coral reefs and monitor the health of our oceans, teeming with marine life.