August 8, 2014
Researchers Adapt Origami Techniques To Create Self-Assembling Robots And Materials
redOrbit Staff & Wire Reports - Your Universe Online
Drawing inspiration from origami, the traditional Japanese art of folding paper into three-dimensional objects, researchers from MIT and Harvard University have created a way to coax flat sheets of composite materials to transform themselves into complex robots capable of performing tasks such as crawling and turning.
Writing in the latest edition of the journal Science, the study authors explained how their robot assembled itself from flat sheets of paper and shape memory polymers which have electronics embedded within them.
The composite was able to fold itself into a dynamic and functional machine in approximately four minutes, they added. Afterwards, it crawled away at a speed of more than two inches per second and was able to turn without any human help, making it the first self-folding machine capable of doing so without additional outside assistance.
“We demonstrated this process by building a robot that folds itself and walks away without human assistance,” lead author Sam Felton, a Ph.D. candidate at Harvard University's School of Engineering and Applied Sciences and the Wyss Institute for Biologically Inspired Engineering, explained in a statement Thursday.
“Folding allows you to avoid the 'nuts and bolts' assembly approaches typically used for robots or other complex electromechanical devices and it allows you to integrate components like electronics, sensors, and actuators while flat,” added senior author Rob Wood, the Charles River Professor of Engineering and Applied Sciences Core Faculty Member at Harvard University's Wyss Institute for Biologically Inspired Engineering.
The new robot is similar to a machine described by Wood and colleagues from Harvard and MIT this spring at the 2014 IEEE International Conference on Robotics and Automation. That robot self-assembled from laser-cut materials when uniformly heated, but the new unit relies on electrical leads instead of a hot plate or oven to deliver heat to the robot’s joints, thus initiating the folding process.
Erik Demaine, an MIT professor of computer science and engineering, and a member of both research teams, called the development of the new robot “exciting from a geometry standpoint, because it lets us fold more things. Because we can do the sequencing, we have a lot more control. And it lets us make active folding structures. Instead of just self-assembly, you can then make it walk.”
According to the researchers, the robot is built from five layers of minerals, each of which is cut to digital specifications using a laser cutter. A middle layer of copper, etched into a network of electrical leads, is placed between two structural layers of paper. The outer layers are made from a special polymer that folds when heated, and once they are all assembled, a microprocessor and at least one small motor are attached to the top surface.
The prototype was assembled manually, but the study authors explain that it could also be put together using a robotic “pick and place” system. The study describes a design that uses two motors, with each one controlling two of the robot’s legs and their activities being synchronized by the microprocessor. In addition, each leg has eight mechanical “linkages,” the dynamics of which convert the force exerted by the motor into movement.
“Getting a robot to assemble itself autonomously and actually perform a function has been a milestone we've been chasing for many years," said Wood, but it isn’t the only new technological breakthrough based on the principals of origami. In fact, a new paper details how a special type of origami fold called Miura-ori could be used to create reprogrammable molecular-scale machines.
The research is the inspiration of University of Massachusetts Amherst physicist Christian Santangelo, who along with physicists and materials scientists from Cornell University and Western New England University, turned to the paper-folding technique for “tuning” the physical properties of thin sheets of materials. Their research could ultimately lead to the development of molecular-scale machines that could snap into place and perform mechanical tasks.
Santangelo first brought up Miura-ori as a potential way to design controllable new materials during a physics meeting several years ago, the university said in a statement. Also known as tessellation, this special type of folding occurs naturally in some types of leaves and tissues. It arranges a flat surface using a repeated, alternating pattern of mountain-and-valley zigzag folds, allowing them to contract like an accordion when they are squeezed.
“As you compress most materials along one axis, they expand in other directions,” explained Santangelo. “A rare class of materials, however, does the opposite. If you compress them along one direction, they collapse uniformly in all directions. Miura-ori shows us how to use this property to make new devices. Exotic materials can be formed from traditional materials simply by altering microscopic structure.”
“We're looking at an origami structure and using a language developed for understanding the mechanical properties of atomic crystals to talk about what we see here,” added fellow investigator and Cornell University graduate student Jesse Silverberg. “Our work brings together origami, metamaterials, programmable matter, crystallography and more. It's totally bizarre and unique to have so many of these ideas intersecting at the same time.”
The researchers ultimately hope that their work will lead to the creation of atomic-scale machines programmed based on folding patterns and are capable of snapping into place and performing mechanical functions.
“You can imagine a folded sheet of some material and popping in defects to make a stiff shield, or somehow deploying an object and giving it a rigid backbone,” said Cornell associate professor of physics Itai Cohen. “Think of it as appendages that can be locked in place or a useful tool whose properties can be set once it has been deployed. In that way, it's kind of like the transformers, where robots fold themselves up but unfurl, locked, into human form.”
Image 2 (below): Jesse Silverberg et al. used origami-based engineering to design a lightweight, ultra-tough material with tunable properties. Their inspiration was a specific type of zigzag origami fold that has previously been used to efficiently pack solar panels for space missions. Credit: Jesse Silverberg, Arthur Evans, Lauren McLeod, Ryan Hayward, Thomas Hull, Christian Santangelo, Itai Cohen
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