The origami bot was developed at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) with the aid of researchers from the University of Sheffield and the Tokyo Institute of Technology. In the U.S., more than 3,500 incidents take place of swallowed button batteries every year and majority of the cases are of toddlers. If these batteries remain in the stomach too long, they can cause internal burns.
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Rus mentioned that an ingestible robot does pose some significant challenges. “For applications inside the body, we need a small, controllable, untethered robot system”.
The robot is swallowed in a capsule and unfolds once in the stomach as its container dissolves.
This sandwiches a material that shrinks when heated, allowing the robot to wriggle its way through the stomach.
Along with removing foreign objects, the robot could be used to perform a variety of tasks within the body, like patching wounds or delivering medicine to a specific location.
Once in the stomach, the robot doesn’t have to work its way out of the capsule it was swallowed in. Miyashita employed a clever strategy to convince Rus that the removal of swallowed button batteries and the treatment of consequent wounds was a compelling application of their origami robot.
To test the robot, the team built a synthetic stomach out of silicone rubber, modelled on the mechanical properties of a pig’s stomach, and filled it with a mixture of water and lemon juice to simulate stomach fluids. When the ice melts, the robot then goes to complete its mission.
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Their research findings are being presented this May 16 to 21 in Stockholm, Sweden, at the IEEE International Conference on Robotics and Automation. The robot primarily uses a “stick-slip” motion, where its appendages cling to a surface, such as the stomach wall, through fiction, but are released when the robot’s body flexes. The demonstration shows that the robot can grab an embedded battery and lift it free, allowing both robot and battery to then pass through the stomach and be excreted normally. The origami robot is quite adept at sliding over to the battery and dislodging it so it can be safely shepherded through the digestive tract. “It’s really hard to control and place a robot inside the body if the robot is attached to a tether”. “In our calculation, 20 percent of forward motion is by propelling water – thrust – and 80 percent is by stick-slip motion”, says Miyashita. “If you have a battery in your body, you really want it out as soon as possible”.
