"It's something we humans can do well, but we don't understand the mechanical details," said Balkcom. "Because a five-year-old child can learn to fold origami, we assume that it is a simple process, but the movements it requires are quite complex."
Balkcom's thesis project uses kinematics, the study of mechanisms, to determine how folding motions are made and how paper can be treated as both a flexible and a rigid material. Because robots are so often used for industrial and manufacturing purposes, they are engineered to work with rigid materials, Balkcom said. Paper presents a significant problem because it is flexible.
"There are a lot of complicated things going on when a human being is folding a piece of paper," he said. "How do we precisely place a crease? We line up the corners and roll it out in the center of the paper. We treat the paper as flexible material, but machines can't do this."
Balkcom built his origami robot with an industrial mechanical arm produced by Adept Technology, Inc., of Livermore, Calif. The robot uses a tiny suction cup attached to the arm to pick the paper up, rotate it and place it over a narrow gutter in the worktable. Then a ruler descends and presses the paper into the gutter to create a crease. This method is much less precise than a human and brings to light some interesting insights and questions about mechanisms.
"Human beings are mechanisms," Balkcom said. "We're very complicated mechanisms and we don't even understand ourselves. People do really neat things with their hands. Can we make robots do these things? If not, can we at least use robots to understand how humans do them?"
Balkcom's advisor, Matthew T. Mason, professor of computer science and robotics, points out the challenges presented by flexible materials and coordinated motions of two different parts at once. "Origami defies description by our current mathematical tools," he said.
Balkcom admits that his thesis is just the beginning.
"Origami is a good problem to study because there is a 'ladder' of origami skills and designs, from the very simple to the complex," he said. Although his thesis will only reach the first few rungs, it will create a basis for further exploration that may lead to more capable robots in general.
"Robots are a tool for understanding the physics and mathematics of the world around us," he said. "Once you build a robot that can duplicate human tasks, you can learn more about human skills that we often take for granted."
Videos of the origami robot folding a paper airplane and a hat are available at www.cs.cmu.edu/~devin.