Tag Archives: CSAIL

Ingestible origami robot gets one step closer

Fiction, more or less seriously, has been exploring the idea of ingestible, tiny robots that can enter the human body for decades (Fantastic Voyage and Innerspace are two movie examples). The concept is coming closer to being realized as per a May 12, 2016 news item on phys.org,

In experiments involving a simulation of the human esophagus and stomach, researchers at MIT [Massachusetts Institute of Technology], the University of Sheffield, and the Tokyo Institute of Technology have demonstrated a tiny origami robot that can unfold itself from a swallowed capsule and, steered by external magnetic fields, crawl across the stomach wall to remove a swallowed button battery or patch a wound.

A May 12, 2016 MIT news release (also on EurekAlert), which originated the news item, provides some fascinating depth to this story (Note: Links have been removed),

The new work, which the researchers are presenting this week at the International Conference on Robotics and Automation, builds on a long sequence of papers on origami robots from the research group of Daniela Rus, the Andrew and Erna Viterbi Professor in MIT’s Department of Electrical Engineering and Computer Science.

“It’s really exciting to see our small origami robots doing something with potential important applications to health care,” says Rus, who also directs MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL). “For applications inside the body, we need a small, controllable, untethered robot system. It’s really difficult to control and place a robot inside the body if the robot is attached to a tether.”

Although the new robot is a successor to one reported at the same conference last year, the design of its body is significantly different. Like its predecessor, it can propel itself using what’s called a “stick-slip” motion, in which its appendages stick to a surface through friction when it executes a move, but slip free again when its body flexes to change its weight distribution.

Also like its predecessor — and like several other origami robots from the Rus group — the new robot consists of two layers of structural material sandwiching a material that shrinks when heated. A pattern of slits in the outer layers determines how the robot will fold when the middle layer contracts.

Material difference

The robot’s envisioned use also dictated a host of structural modifications. “Stick-slip only works when, one, the robot is small enough and, two, the robot is stiff enough,” says Guitron [Steven Guitron, a graduate student in mechanical engineering]. “With the original Mylar design, it was much stiffer than the new design, which is based on a biocompatible material.”

To compensate for the biocompatible material’s relative malleability, the researchers had to come up with a design that required fewer slits. At the same time, the robot’s folds increase its stiffness along certain axes.

But because the stomach is filled with fluids, the robot doesn’t rely entirely on stick-slip motion. “In our calculation, 20 percent of forward motion is by propelling water — thrust — and 80 percent is by stick-slip motion,” says Miyashita [Shuhei Miyashita, who was a postdoc at CSAIL when the work was done and is now a lecturer in electronics at the University of York, England]. “In this regard, we actively introduced and applied the concept and characteristics of the fin to the body design, which you can see in the relatively flat design.”

It also had to be possible to compress the robot enough that it could fit inside a capsule for swallowing; similarly, when the capsule dissolved, the forces acting on the robot had to be strong enough to cause it to fully unfold. Through a design process that Guitron describes as “mostly trial and error,” the researchers arrived at a rectangular robot with accordion folds perpendicular to its long axis and pinched corners that act as points of traction.

In the center of one of the forward accordion folds is a permanent magnet that responds to changing magnetic fields outside the body, which control the robot’s motion. The forces applied to the robot are principally rotational. A quick rotation will make it spin in place, but a slower rotation will cause it to pivot around one of its fixed feet. In the researchers’ experiments, the robot uses the same magnet to pick up the button battery.

Porcine precedents

The researchers tested about a dozen different possibilities for the structural material before settling on the type of dried pig intestine used in sausage casings. “We spent a lot of time at Asian markets and the Chinatown market looking for materials,” Li [Shuguang Li, a CSAIL postdoc] says. The shrinking layer is a biodegradable shrink wrap called Biolefin.

To design their synthetic stomach, the researchers bought a pig stomach and tested its mechanical properties. Their model is an open cross-section of the stomach and esophagus, molded from a silicone rubber with the same mechanical profile. A mixture of water and lemon juice simulates the acidic fluids in the stomach.

Every year, 3,500 swallowed button batteries are reported in the U.S. alone. Frequently, the batteries are digested normally, but if they come into prolonged contact with the tissue of the esophagus or stomach, they can cause an electric current that produces hydroxide, which burns the tissue. 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.

“Shuhei bought a piece of ham, and he put the battery on the ham,” Rus says. [emphasis mine] “Within half an hour, the battery was fully submerged in the ham. So that made me realize that, yes, this is important. If you have a battery in your body, you really want it out as soon as possible.”

“This concept is both highly creative and highly practical, and it addresses a clinical need in an elegant way,” says Bradley Nelson, a professor of robotics at the Swiss Federal Institute of Technology Zurich. “It is one of the most convincing applications of origami robots that I have seen.”

I wonder if they ate the ham afterwards.

Happily, MIT has produced a video featuring this ingestible, origami robot,

Finally, this team has a couple more members than the previously mentioned Rus, Miyashita, and Li,

…  Kazuhiro Yoshida of Tokyo Institute of Technology, who was visiting MIT on sabbatical when the work was done; and Dana Damian of the University of Sheffield, in England.

As Rus notes in the video, the next step will be in vivo (animal) studies.

POD (print-on-demand) robots

I’ve heard of print-on-demand (POD) books before but not robots as per the April 4, 2012 article on BBC News online (link to National Science Foundation removed),

Researchers aim to build a desktop technology that would allow an average person to design and print a machine within 24 hours.

The team says that making it easier to create specialised robots could have a “profound impact on society”.

The effort is being funded by a $10m (£6.3m) grant from the National Science Foundation [NSF].

The Virginia-based organization [NSF] described the move as a “game changing investment”.

“It has the potential to democratise and personalise automation to meet the needs of individual users – whether for search and rescue workers in remote areas of the world or educators in classrooms around the US – possibilities for social impact abound,” said spokeswoman Lisa-Joy Zgorski.

The April 3, 2012 MIT (Massachusetts Institute of Technology) news item by Abby Abazorius provides more detail,

“This research envisions a whole new way of thinking about the design and manufacturing of robots, and could have a profound impact on society,” says MIT Professor Daniela Rus, leader of the project and a principal investigator at the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL). “We believe that it has the potential to transform manufacturing and to democratize access to robots.”

“Our goal is to develop technology that enables anyone to manufacture their own customized robot. This is truly a game changer,” says Professor Vijay Kumar, who is leading the team from the University of Pennsylvania. “It could allow for the rapid design and manufacture of customized goods, and change the way we teach science and technology in high schools.”

The five-year project, called “An Expedition in Computing for Compiling Printable Programmable Machines,” brings together a team of researchers from MIT, the University of Pennsylvania and Harvard University, and is funded as part of the NSF’s “Expeditions in Computing” program.

It currently takes years to produce, program and design a functioning robot, and is an extremely expensive process, involving hardware and software design, machine learning and vision, and advanced programming techniques. The new project would automate the process of producing functional 3-D devices and allow individuals to design and build functional robots from materials as easily accessible as a sheet of paper.


Researchers hope to create a platform that would allow an individual to identify a household problem that needs assistance; then head to a local printing store to select a blueprint, from a library of robotic designs; and then customize an easy-to-use robotic device that could solve the problem. Within 24 hours, the robot would be printed, assembled, fully programmed and ready for action.

By altering the way in which machines can be produced, designed and built, the project could have far reaching implications for a variety of fields.

“This project aims to dramatically reduce the development time for a variety of useful robots, opening the doors to potential applications in manufacturing, education, personalized health care and even disaster relief,” says Rob Wood, an associate professor at Harvard University.


Thus far, the research team has prototyped two machines for designing, printing and programming, including an insect-like robot that could be used for exploring a contaminated area and a gripper that could be used by people with limited mobility.

Here’s a video demonstrating a few of the prototypes the team has developed (an “insect-like robot that could be used for exploring a contaminated area and a gripper that could be used by people with limited mobility”).

You can find out more about the CSAIL project at MIT here.

Other research collaborators on the five-year NSF project include Visiting Scientist Martin Demaine, Associate Professor Wojciech Matusik, Professor Martin Rinard, and Assistant Professor Sangbae Kim of MIT. Besides Wood (Harvard) and Kumar (UPenn), the team also includes Associate Professor Andre DeHon, Professor Sanjeev Khanna and Professor Insup Lee, all from UPenn.