Often the most incredible innovations come in the tiniest packages. That is certainly true for the origami robots created by some Massachusetts Institute of Technology (MIT) researchers. The microbots that made their debut earlier this summer at the International Conference on Robotics and Automation in Seattle, WA, are not just adorable. They also possess skills that may come in handy to combat human ailments.
What's interesting is that the minuscule robot which sits about 1.5 centimeters tall and weighs one-third of a gram has no complicated machinery. MIT graduate student Cynthia R. Sung, co-developer of the robot says unlike traditional robots, all these motions are "embedded into the mechanics of the robot body." This means that it does not need external "legs," motors, or other movement-enabling appendages to be mobile.
In fact, the blueprint of the robot is surprisingly straightforward. The only components are some self-folding sheets and a tiny neodymium magnet. But don't let this simple design fool you. This simple microbot can walk, swim, climb, and even overcome obstacles, all while carrying a load twice its weight. While that may appear to be almost magical, the robot's talents are rooted in scientific principles.
The robot's amazing self-folding powers can be attributed to the sheet of polyvinyl chloride embedded within each of the several prototypes created by its inventors to find the optimal material. The commonly found plastic contracts when subjected to temperatures of about 150° F.
Hence when the flat sheets are exposed to heat, they fold up, enabling the robot to "come to life." Once that happens, the tiny magnet attached to the back takes over by connecting with external magnetic fields. The scientists control the microbot's movements by applying the magnetic fields in varying sequences.
For example, one course would entail lifting the robot's back "feet" off the ground while the front stayed adhered due to friction. The next sequence causes the body to twist, lifting the front feet off the ground and propelling the bot forward as if it were walking. By alternating these magnetic fields, the robot can be moved in a variety of ways.
In experiments, the robots were tested on a rectangular stage with strong electromagnets positioned in all four corners. This allowed the researchers to change the electromagnetic fields rapidly enough to enable the microbot to move about four body lengths per second.
To ensure the robot consistently folded in the required form, the scientists cut slits of varying widths into the outer layers of the self-folding material used. When the sheet was exposed to heat, the middle layer contracted, forcing the narrower slit's edges together causing it to bend in the opposite direction. If another form was desired, the researchers merely exposed the material to a slightly lower or higher temperature, which in turn would cause the folds to contract in a totally different way.
What's even cooler is that the prototypes were made from liquid soluble materials. One whose outer layers comprised of polystyrene completely dissolved when dunked in an acetone solution. Another was water soluble. The robot's ability to "self-destruct" is of utmost importance. That's because the possible use of the tiny bot is to heal humans by zapping cancer cells, cleaning clogged arteries, or sensing foreign materials.
In theory, robots even smaller than these would be injected into the human body in their flat form and transported to the area requiring care via the blood stream. Once there, the microbots would come to life using a yet to be determined heat source, complete their mission, and then simply dissolve.
Shuhei Miyashita, a post-doctoral student, involved in the robot's development notes that with the innovative design, "we complete the cycle from birth through life, activity, and the end of life." The scientists clearly have more work to do before the origami robot is ready for human use. However, this is certainly a step in the right direction.
Resources: newsoffice,mit.edu, spectrum.iee.org, newscientist.com