Autonomous, self-contained soft robotic fish at MIT
We are developing soft-bodied robots and there are three important things to know about these robots. First, their bodies are made out of soft silicon and they can bend and twist because of that. They’re also inherently safe to be around. Second, because of their bodies capability to bend and twist, these robots are capable of very compliant motion and they’re also capable of very rapid agile maneuvers which pushes the envelope on what machines can do today. And, thirdly, the robots are self-contained and autonomous; in other words we can package the power source, the computation and the actuation and sensing needed for these robots to deliver their motions. Traditionally soft robots have been either self-contained or capable of high-performance, but not both. So specifically in our lab we want to achieve both of those goals simultaneously in one machine. Currently a soft robot has two parts. One, which is a little bit smaller, is the rigid part where we store all the supporting hardware. And the second part, which is a little bit larger, is the soft body where all the continuous, natural movement happens. And so when we thought about it, a fish made sense. It has a very similar structure: in the head of the fish where the brains are held, it is a little bit more rigid, but in the rear of the fish where the angulatory motion happens, it’s quite soft and compliant. This is our soft robot fish. Like we said, he has a soft body here in green and the supporting hardware up front. The way this fish works is it stores fluid onboard, in the form of a gas, and then releases this gas through a series of pipes and valves into the body. If you think about it, it is very similar to blowing up a balloon. In that case, your mouth would be the pressure source and the balloon would be the body actuator. And basically by inflating and un-inflating different parts of of the body we can get it to angulate. What is special about this fish is it has its brains onboard too. So if I, from my computer, tell the fish to move forward a signal is sent wirelessly through the water to the brains and then the brains tell the hardware what to do in order to move forward. Biological fish use the ‘escape maneuver’ or the ‘c-turn’ to escape prey and they do these maneuvers very fast; on the order of 100 milliseconds. Our robot fish is also able to execute this escape maneuver at the same speed: 100 milliseconds. The fact that our fish can perform an escape maneuver is really important for the field of soft robotics. It shows that soft robots can be both self-contained and capable of high performance. The maneuver is so fast and it has got such high body curvature that it shows soft robots might be more capable than hard robots in some tasks.