All posts by MIT News

MIT researchers have developed resilient artificial muscles that can enable insect-scale aerial robots to effectively recover flight performance after suffering severe damage. Photo: Courtesy of the researchers

By Adam Zewe | MIT News Office

Bumblebees are clumsy fliers. It is estimated that a foraging bee bumps into a flower about once per second, which damages its wings over time. Yet despite having many tiny rips or holes in their wings, bumblebees can still fly.

Aerial robots, on the other hand, are not so resilient. Poke holes in the robot’s wing motors or chop off part of its propellor, and odds are pretty good it will be grounded.

Inspired by the hardiness of bumblebees, MIT researchers have developed repair techniques that enable a bug-sized aerial robot to sustain severe damage to the actuators, or artificial muscles, that power its wings — but to still fly effectively.

They optimized these artificial muscles so the robot can better isolate defects and overcome minor damage, like tiny holes in the actuator. In addition, they demonstrated a novel laser repair method that can help the robot recover from severe damage, such as a fire that scorches the device.

Using their techniques, a damaged robot could maintain flight-level performance after one of its artificial muscles was jabbed by 10 needles, and the actuator was still able to operate after a large hole was burnt into it. Their repair methods enabled a robot to keep flying even after the researchers cut off 20 percent of its wing tip.

This could make swarms of tiny robots better able to perform tasks in tough environments, like conducting a search mission through a collapsing building or dense forest.

“We spent a lot of time understanding the dynamics of soft, artificial muscles and, through both a new fabrication method and a new understanding, we can show a level of resilience to damage that is comparable to insects,” says Kevin Chen, the D. Reid Weedon, Jr. Assistant Professor in the Department of Electrical Engineering and Computer Science (EECS), the head of the Soft and Micro Robotics Laboratory in the Research Laboratory of Electronics (RLE), and the senior author of the paper on these latest advances. “We’re very excited about this. But the insects are still superior to us, in the sense that they can lose up to 40 percent of their wing and still fly. We still have some catch-up work to do.”

Chen wrote the paper with co-lead authors Suhan Kim and Yi-Hsuan Hsiao, who are EECS graduate students; Younghoon Lee, a postdoc; Weikun “Spencer” Zhu, a graduate student in the Department of Chemical Engineering; Zhijian Ren, an EECS graduate student; and Farnaz Niroui, the EE Landsman Career Development Assistant Professor of EECS at MIT and a member of the RLE. The article appeared in Science Robotics.

Robot repair techniques

Using the repair techniques developed by MIT researchers, this microrobot can still maintain flight-level performance even after the artificial muscles that power its wings were jabbed by 10 needles and 20 percent of one wing tip was cut off. Credit: Courtesy of the researchers.

The tiny, rectangular robots being developed in Chen’s lab are about the same size and shape as a microcassette tape, though one robot weighs barely more than a paper clip. Wings on each corner are powered by dielectric elastomer actuators (DEAs), which are soft artificial muscles that use mechanical forces to rapidly flap the wings. These artificial muscles are made from layers of elastomer that are sandwiched between two razor-thin electrodes and then rolled into a squishy tube. When voltage is applied to the DEA, the electrodes squeeze the elastomer, which flaps the wing.

But microscopic imperfections can cause sparks that burn the elastomer and cause the device to fail. About 15 years ago, researchers found they could prevent DEA failures from one tiny defect using a physical phenomenon known as self-clearing. In this process, applying high voltage to the DEA disconnects the local electrode around a small defect, isolating that failure from the rest of the electrode so the artificial muscle still works.

Chen and his collaborators employed this self-clearing process in their robot repair techniques.

First, they optimized the concentration of carbon nanotubes that comprise the electrodes in the DEA. Carbon nanotubes are super-strong but extremely tiny rolls of carbon. Having fewer carbon nanotubes in the electrode improves self-clearing, since it reaches higher temperatures and burns away more easily. But this also reduces the actuator’s power density.

“At a certain point, you will not be able to get enough energy out of the system, but we need a lot of energy and power to fly the robot. We had to find the optimal point between these two constraints — optimize the self-clearing property under the constraint that we still want the robot to fly,” Chen says.

However, even an optimized DEA will fail if it suffers from severe damage, like a large hole that lets too much air into the device.

Chen and his team used a laser to overcome major defects. They carefully cut along the outer contours of a large defect with a laser, which causes minor damage around the perimeter. Then, they can use self-clearing to burn off the slightly damaged electrode, isolating the larger defect.

“In a way, we are trying to do surgery on muscles. But if we don’t use enough power, then we can’t do enough damage to isolate the defect. On the other hand, if we use too much power, the laser will cause severe damage to the actuator that won’t be clearable,” Chen says.

The team soon realized that, when “operating” on such tiny devices, it is very difficult to observe the electrode to see if they had successfully isolated a defect. Drawing on previous work, they incorporated electroluminescent particles into the actuator. Now, if they see light shining, they know that part of the actuator is operational, but dark patches mean they successfully isolated those areas.

The new research could make swarms of tiny robots better able to perform tasks in tough environments, like conducting a search mission through a collapsing building or dense forest. Photo: Courtesy of the researchers

Flight test success

Once they had perfected their techniques, the researchers conducted tests with damaged actuators — some had been jabbed by many needles while other had holes burned into them. They measured how well the robot performed in flapping wing, take-off, and hovering experiments.

Even with damaged DEAs, the repair techniques enabled the robot to maintain its flight performance, with altitude, position, and attitude errors that deviated only very slightly from those of an undamaged robot. With laser surgery, a DEA that would have been broken beyond repair was able to recover 87 percent of its performance.

“I have to hand it to my two students, who did a lot of hard work when they were flying the robot. Flying the robot by itself is very hard, not to mention now that we are intentionally damaging it,” Chen says.

These repair techniques make the tiny robots much more robust, so Chen and his team are now working on teaching them new functions, like landing on flowers or flying in a swarm. They are also developing new control algorithms so the robots can fly better, teaching the robots to control their yaw angle so they can keep a constant heading, and enabling the robots to carry a tiny circuit, with the longer-term goal of carrying its own power source.

“This work is important because small flying robots — and flying insects! — are constantly colliding with their environment. Small gusts of wind can be huge problems for small insects and robots. Thus, we need methods to increase their resilience if we ever hope to be able to use robots like this in natural environments,” says Nick Gravish, an associate professor in the Department of Mechanical and Aerospace Engineering at the University of California at San Diego, who was not involved with this research. “This paper demonstrates how soft actuation and body mechanics can adapt to damage and I think is an impressive step forward.”

This work is funded, in part, by the National Science Foundation (NSF) and a MathWorks Fellowship.

• PAPER – Laser-assisted failure recovery for dielectric elastomer actuators in aerial robots. Suhan Kim, Yi-Hsuan Hsiao, Younghoon Lee, Weikun Zhu, Zhijian Ren, Farnaz Niroui, and Yufeng Chen. Science Robotics, 8(76), eadf4278.

A team of MIT engineers is designing a kit of universal robotic parts that an astronaut could easily mix and match to build different robot “species” to fit various missions on the moon. Credit: hexapod image courtesy of the researchers, edited by MIT News

By Jennifer Chu | MIT News Office

When astronauts begin to build a permanent base on the moon, as NASA plans to do in the coming years, they’ll need help. Robots could potentially do the heavy lifting by laying cables, deploying solar panels, erecting communications towers, and building habitats. But if each robot is designed for a specific action or task, a moon base could become overrun by a zoo of machines, each with its own unique parts and protocols.

To avoid a bottleneck of bots, a team of MIT engineers is designing a kit of universal robotic parts that an astronaut could easily mix and match to rapidly configure different robot “species” to fit various missions on the moon. Once a mission is completed, a robot can be disassembled and its parts used to configure a new robot to meet a different task.

The team calls the system WORMS, for the Walking Oligomeric Robotic Mobility System. The system’s parts include worm-inspired robotic limbs that an astronaut can easily snap onto a base, and that work together as a walking robot. Depending on the mission, parts can be configured to build, for instance, large “pack” bots capable of carrying heavy solar panels up a hill. The same parts could be reconfigured into six-legged spider bots that can be lowered into a lava tube to drill for frozen water.

“You could imagine a shed on the moon with shelves of worms,” says team leader George Lordos, a PhD candidate and graduate instructor in MIT’s Department of Aeronautics and Astronautics (AeroAstro), in reference to the independent, articulated robots that carry their own motors, sensors, computer, and battery. “Astronauts could go into the shed, pick the worms they need, along with the right shoes, body, sensors and tools, and they could snap everything together, then disassemble it to make a new one. The design is flexible, sustainable, and cost-effective.”

Lordos’ team has built and demonstrated a six-legged WORMS robot. Last week, they presented their results at IEEE’s Aerospace Conference, where they also received the conference’s Best Paper Award.

MIT team members include Michael J. Brown, Kir Latyshev, Aileen Liao, Sharmi Shah, Cesar Meza, Brooke Bensche, Cynthia Cao, Yang Chen, Alex S. Miller, Aditya Mehrotra, Jacob Rodriguez, Anna Mokkapati, Tomas Cantu, Katherina Sapozhnikov, Jessica Rutledge, David Trumper, Sangbae Kim, Olivier de Weck, Jeffrey Hoffman, along with Aleks Siemenn, Cormac O’Neill, Diego Rivero, Fiona Lin, Hanfei Cui, Isabella Golemme, John Zhang, Jolie Bercow, Prajwal Mahesh, Stephanie Howe, and Zeyad Al Awwad, as well as Chiara Rissola of Carnegie Mellon University and Wendell Chun of the University of Denver.

Animal instincts

WORMS was conceived in 2022 as an answer to NASA’s Breakthrough, Innovative and Game-changing (BIG) Idea Challenge — an annual competition for university students to design, develop, and demonstrate a game-changing idea. In 2022, NASA challenged students to develop robotic systems that can move across extreme terrain, without the use of wheels.

A team from MIT’s Space Resources Workshop took up the challenge, aiming specifically for a lunar robot design that could navigate the extreme terrain of the moon’s South Pole — a landscape that is marked by thick, fluffy dust; steep, rocky slopes; and deep lava tubes. The environment also hosts “permanently shadowed” regions that could contain frozen water, which, if accessible, would be essential for sustaining astronauts.

As they mulled over ways to navigate the moon’s polar terrain, the students took inspiration from animals. In their initial brainstorming, they noted certain animals could conceptually be suited to certain missions: A spider could drop down and explore a lava tube, a line of elephants could carry heavy equipment while supporting each other down a steep slope, and a goat, tethered to an ox, could help lead the larger animal up the side of a hill as it transports an array of solar panels.

“As we were thinking of these animal inspirations, we realized that one of the simplest animals, the worm, makes similar movements as an arm, or a leg, or a backbone, or a tail,” says deputy team leader and AeroAstro graduate student Michael Brown. “And then the lightbulb went off: We could build all these animal-inspired robots using worm-like appendages.’”

The research team in Killian Court at MIT. Credit: Courtesy of the researchers

Snap on, snap off

Lordos, who is of Greek descent, helped coin WORMS, and chose the letter “O” to stand for “oligomeric,” which in Greek signifies “a few parts.”

“Our idea was that, with just a few parts, combined in different ways, you could mix and match and get all these different robots,” says AeroAstro undergraduate Brooke Bensche.

The system’s main parts include the appendage, or worm, which can be attached to a body, or chassis, via a “universal interface block” that snaps the two parts together through a twist-and-lock mechanism. The parts can be disconnected with a small tool that releases the block’s spring-loaded pins.

Appendages and bodies can also snap into accessories such as a “shoe,” which the team engineered in the shape of a wok, and a LiDAR system that can map the surroundings to help a robot navigate.

“In future iterations we hope to add more snap-on sensors and tools, such as winches, balance sensors, and drills,” says AeroAstro undergraduate Jacob Rodriguez.

The team developed software that can be tailored to coordinate multiple appendages. As a proof of concept, the team built a six-legged robot about the size of a go-cart. In the lab, they showed that once assembled, the robot’s independent limbs worked to walk over level ground. The team also showed that they could quickly assemble and disassemble the robot in the field, on a desert site in California.

In its first generation, each WORMS appendage measures about 1 meter long and weighs about 20 pounds. In the moon’s gravity, which is about one-sixth that of Earth’s, each limb would weigh about 3 pounds, which an astronaut could easily handle to build or disassemble a robot in the field. The team has planned out the specs for a larger generation with longer and slightly heavier appendages. These bigger parts could be snapped together to build “pack” bots, capable of transporting heavy payloads.

“There are many buzz words that are used to describe effective systems for future space exploration: modular, reconfigurable, adaptable, flexible, cross-cutting, et cetera,” says Kevin Kempton, an engineer at NASA’s Langley Research Center, who served as a judge for the 2022 BIG Idea Challenge. “The MIT WORMS concept incorporates all these qualities and more.”

This research was supported, in part, by NASA, MIT, the Massachusetts Space Grant, the National Science Foundation, and the Fannie and John Hertz Foundation.

• PAPER – WORMS: Field-Reconfigurable Robots for Extreme Lunar Terrain. George Lordos, Michael J. Brown, Kir Latyshev, and Aileen Liao. Proceedings of IEEE Aerospace 2023.

Shua Cho works on her artwork in “Introduction to Physical Computing for Artists” at the MIT Student Art Association. Photo: Sarah Bastille

By Ken Shulman | Arts at MIT

One student confesses that motors have always freaked them out. Amy Huynh, a first-year student in the MIT Technology and Policy Program, says “I just didn’t respond to the way electrical engineering and coding is usually taught.”

Huynh and her fellow students found a different way to master coding and circuits during the Independent Activities Period course Introduction to Physical Computing for Artists — a class created by Student Art Association (SAA) instructor Timothy Lee and offered for the first time last January. During the four-week course, students learned to use circuits, wiring, motors, sensors, and displays by developing their own kinetic artworks. 

“It’s a different approach to learning about art, and about circuits,” says Lee, who joined the SAA instructional staff last June after completing his MFA at Goldsmiths, University of London. “Some classes can push the technology too quickly. Here we try to take away the obstacles to learning, to create a collaborative environment, and to frame the technology in the broader concept of making an artwork. For many students, it’s a very effective way to learn.”

Lee graduated from Wesleyan University with three concurrent majors in neuroscience, biology, and studio art. “I didn’t have a lot of free time,” says Lee, who originally intended to attend medical school before deciding to follow his passion for making art. “But I benefited from studying both science and art. Just as I almost always benefited from learning from my peers. I draw on both of those experiences in designing and teaching this class.”

On this January evening, the third of four scheduled classes, Lee leads his students through an exercise to create an MVP — a minimum viable product of their art project. The MVP, he explains, serves as an artist’s proof of concept. “This is the smallest single unit that can demonstrate that your project is doable,” he says. “That you have the bare-minimum functioning hardware and software that shows your project can be scalable to your vision. Our work here is different from pure robotics or pure electronics. Here, the technology and the coding don’t need to be perfect. They need to support your aesthetic and conceptual goals. And here, these things can also be fun.”

Lee distributes various electronic items to the students according to their specific needs — wires, soldering irons, resistors, servo motors, and Arduino components. The students have already acquired a working knowledge of coding and the Arduino language in the first two class sessions. Sophomore Shua Cho is designing an evening gown bedecked with flowers that will open and close continuously. Her MVP is a cluster of three blossoms, mounted on a single post that, when raised and lowered, opens and closes the sewn blossoms. She asks Lee for help in attaching a servo motor — an electronic motor that alternates between 0, 90, and 180 degrees — to the post. Two other students, working on similar problems, immediately pull their chairs beside Cho and Lee to join the discussion. 

Shua Cho is designing an evening gown bedecked with flowers that will open and close continuously. Her minimum viable product is a cluster of three blossoms, mounted on a single post that, when raised and lowered, opens and closes the sewn blossoms. Photo: Sarah Bastille

The instructor suggests they observe the dynamics of an old-fashioned train locomotive wheel. One student calls up the image on their laptop. Then, as a group, they reach a solution for Cho — an assembly of wire and glue that will attach the servo engine to the central post, opening and closing the blossoms. It’s improvised, even inelegant. But it works, and proves that the project for the blossom-covered kinetic dress is viable.  

“This is one of the things I love about MIT,” says aeronautical and astronautical engineering senior Hannah Munguia. Her project is a pair of hands that, when triggered by a motion sensor, will applaud when anyone walks by. “People raise their hand when they don’t understand something. And other people come to help. The students here trust each other, and are willing to collaborate.”

Student Hannah Munguia (left), instructor Timothy Lee (center), and student Bryan Medina work on artwork in “Introduction to Physical Computing for Artists” at the MIT Student Art Association. Photo: Sarah Bastille

Cho, who enjoys exploring the intersection between fashion and engineering, discovered Lee’s work on Instagram long before she decided to enroll at MIT. “And now I have the chance to study with him,” says Cho, who works at Infinite — MIT’s fashion magazine — and takes classes in both mechanical engineering and design. “I find that having a creative project like this one, with a goal in mind, is the best way for me to learn. I feel like it reinforces my neural pathways, and I know it helps me retain information. I find myself walking down the street or in my room, thinking about possible solutions for this gown. It never feels like work.”

For Lee, who studied computational art during his master’s program, his course is already a successful experiment. He’d like to offer a full-length version of “Introduction to Physical Computing for Artists” during the school year. With 10 sessions instead of four, he says, students would be able to complete their projects, instead of stopping at an MVP.   

“Prior to coming to MIT, I’d only taught at art institutions,” says Lee. “Here, I needed to revise my focus, to redefine the value of art education for students who most likely were not going to pursue art as a profession. For me, the new definition was selecting a group of skills that are necessary in making this type of art, but that can also be applied to other areas and fields. Skills like sensitivity to materials, tactile dexterity, and abstract thinking. Why not learn these skills in an atmosphere that is experimental, visually based, sometimes a little uncomfortable. And why not learn that you don’t need to be an artist to make art. You just have to be excited about it.”

MIT engineers are hoping to help doctors tailor treatments to patients’ specific heart form and function, with a custom robotic heart. The team has developed a procedure to 3D print a soft and flexible replica of a patient’s heart. Image: Melanie Gonick, MIT

By Jennifer Chu | MIT News Office

No two hearts beat alike. The size and shape of the the heart can vary from one person to the next. These differences can be particularly pronounced for people living with heart disease, as their hearts and major vessels work harder to overcome any compromised function.

MIT engineers are hoping to help doctors tailor treatments to patients’ specific heart form and function, with a custom robotic heart. The team has developed a procedure to 3D print a soft and flexible replica of a patient’s heart. They can then control the replica’s action to mimic that patient’s blood-pumping ability.

The procedure involves first converting medical images of a patient’s heart into a three-dimensional computer model, which the researchers can then 3D print using a polymer-based ink. The result is a soft, flexible shell in the exact shape of the patient’s own heart. The team can also use this approach to print a patient’s aorta — the major artery that carries blood out of the heart to the rest of the body.

To mimic the heart’s pumping action, the team has fabricated sleeves similar to blood pressure cuffs that wrap around a printed heart and aorta. The underside of each sleeve resembles precisely patterned bubble wrap. When the sleeve is connected to a pneumatic system, researchers can tune the outflowing air to rhythmically inflate the sleeve’s bubbles and contract the heart, mimicking its pumping action. 

The researchers can also inflate a separate sleeve surrounding a printed aorta to constrict the vessel. This constriction, they say, can be tuned to mimic aortic stenosis — a condition in which the aortic valve narrows, causing the heart to work harder to force blood through the body.

Doctors commonly treat aortic stenosis by surgically implanting a synthetic valve designed to widen the aorta’s natural valve. In the future, the team says that doctors could potentially use their new procedure to first print a patient’s heart and aorta, then implant a variety of valves into the printed model to see which design results in the best function and fit for that particular patient. The heart replicas could also be used by research labs and the medical device industry as realistic platforms for testing therapies for various types of heart disease.

“All hearts are different,” says Luca Rosalia, a graduate student in the MIT-Harvard Program in Health Sciences and Technology. “There are massive variations, especially when patients are sick. The advantage of our system is that we can recreate not just the form of a patient’s heart, but also its function in both physiology and disease.”

Rosalia and his colleagues report their results in a study appearing in Science Robotics. MIT co-authors include Caglar Ozturk, Debkalpa Goswami, Jean Bonnemain, Sophie Wang, and Ellen Roche, along with Benjamin Bonner of Massachusetts General Hospital, James Weaver of Harvard University, and Christopher Nguyen, Rishi Puri, and Samir Kapadia at the Cleveland Clinic in Ohio.

Print and pump

In January 2020, team members, led by mechanical engineering professor Ellen Roche, developed a “biorobotic hybrid heart” — a general replica of a heart, made from synthetic muscle containing small, inflatable cylinders, which they could control to mimic the contractions of a real beating heart.

Shortly after those efforts, the Covid-19 pandemic forced Roche’s lab, along with most others on campus, to temporarily close. Undeterred, Rosalia continued tweaking the heart-pumping design at home.

“I recreated the whole system in my dorm room that March,” Rosalia recalls.

Months later, the lab reopened, and the team continued where it left off, working to improve the control of the heart-pumping sleeve, which they tested in animal and computational models. They then expanded their approach to develop sleeves and heart replicas that are specific to individual patients. For this, they turned to 3D printing.

“There is a lot of interest in the medical field in using 3D printing technology to accurately recreate patient anatomy for use in preprocedural planning and training,” notes Wang, who is a vascular surgery resident at Beth Israel Deaconess Medical Center in Boston.

An inclusive design

In the new study, the team took advantage of 3D printing to produce custom replicas of actual patients’ hearts. They used a polymer-based ink that, once printed and cured, can squeeze and stretch, similarly to a real beating heart.

As their source material, the researchers used medical scans of 15 patients diagnosed with aortic stenosis. The team converted each patient’s images into a three-dimensional computer model of the patient’s left ventricle (the main pumping chamber of the heart) and aorta. They fed this model into a 3D printer to generate a soft, anatomically accurate shell of both the ventricle and vessel.

The action of the soft, robotic models can be controlled to mimic the patient’s blood-pumping ability. Image: Melanie Gonick, MIT

The team also fabricated sleeves to wrap around the printed forms. They tailored each sleeve’s pockets such that, when wrapped around their respective forms and connected to a small air pumping system, the sleeves could be tuned separately to realistically contract and constrict the printed models.

The researchers showed that for each model heart, they could accurately recreate the same heart-pumping pressures and flows that were previously measured in each respective patient.

“Being able to match the patients’ flows and pressures was very encouraging,” Roche says. “We’re not only printing the heart’s anatomy, but also replicating its mechanics and physiology. That’s the part that we get excited about.”

Going a step further, the team aimed to replicate some of the interventions that a handful of the patients underwent, to see whether the printed heart and vessel responded in the same way. Some patients had received valve implants designed to widen the aorta. Roche and her colleagues implanted similar valves in the printed aortas modeled after each patient. When they activated the printed heart to pump, they observed that the implanted valve produced similarly improved flows as in actual patients following their surgical implants.

Finally, the team used an actuated printed heart to compare implants of different sizes, to see which would result in the best fit and flow — something they envision clinicians could potentially do for their patients in the future.

“Patients would get their imaging done, which they do anyway, and we would use that to make this system, ideally within the day,” says co-author Nguyen. “Once it’s up and running, clinicians could test different valve types and sizes and see which works best, then use that to implant.”

Ultimately, Roche says the patient-specific replicas could help develop and identify ideal treatments for individuals with unique and challenging cardiac geometries.

“Designing inclusively for a large range of anatomies, and testing interventions across this range, may increase the addressable target population for minimally invasive procedures,” Roche says.

This research was supported, in part, by the National Science Foundation, the National Institutes of Health, and the National Heart Lung Blood Institute.

• PAPER – Soft robotic patient-specific hydrodynamic model of aortic stenosis and ventricular remodeling. Luca Rosalia, Caglar Ozturk, Debkalpa Goswami, Jean Bonnemain, Sophie X. Wang, Benjamin Bonner, James C. Weaver, Rishi Puri, Samir Kapadia, Christopher T. Nguyen, and Ellen T. Roche. Science Robotics, 8 (75).

“I observed assistive technologies — developed by scientists and engineers my friends and I never met — which liberated us. My dream has always been to be one of those engineers.” Hermus says. Credit: Tony Pulsone

By Michaela Jarvis | Department of Mechanical Engineering

Before James Hermus started elementary school, he was a happy, curious kid who loved to learn. By the end of first grade, however, all that started to change, he says. As his schoolbooks became more advanced, Hermus could no longer memorize the words on each page, and pretend to be reading. He clearly knew the material the teacher presented in class; his teachers could not understand why he was unable to read and write his assignments. He was accused of being lazy and not trying hard enough.

Hermus was fortunate to have parents who sought out neuropsychology testing — which documented an enormous discrepancy between his native intelligence and his symbol decoding and phonemic awareness. Yet despite receiving a diagnosis of dyslexia, Hermus and his family encountered resistance at his school. According to Hermus, the school’s reading specialist did not “believe” in dyslexia, and, he says, the principal threatened his family with truancy charges when they took him out of school each day to attend tutoring.

Hermus’ school, like many across the country, was reluctant to provide accommodations for students with learning disabilities who were not two years behind in two subjects, Hermus says. For this reason, obtaining and maintaining accommodations, such as extended time and a reader, was a constant battle from first through 12th grade: Students who performed well lost their right to accommodations. Only through persistence and parental support did Hermus succeed in an educational system which he says all too often fails students with learning disabilities.

By the time Hermus was in high school, he had to become a strong self-advocate. In order to access advanced courses, he needed to be able to read more and faster, so he sought out adaptive technology — Kurzweil, a text-to-audio program. This, he says, was truly life-changing. At first, to use this program he had to disassemble textbooks, feed the pages through a scanner, and digitize them.

After working his way to the University of Wisconsin at Madison, Hermus found a research opportunity in medical physics and then later in biomechanics. Interestingly, the steep challenges that Hermus faced during his education had developed in him “the exact skill set that makes a successful researcher,” he says. “I had to be organized, advocate for myself, seek out help to solve problems that others had not seen before, and be excessively persistent.”

While working as a member of Professor Darryl Thelen’s Neuromuscular Biomechanics Lab at Madison, Hermus helped design and test a sensor for measuring tendon stress. He recognized his strengths in mechanical design. During this undergraduate research, he co-authored numerous journal and conference papers. These experiences and a desire to help people with physical disabilities propelled him to MIT.

“MIT is an incredible place. The people in MechE at MIT are extremely passionate and unassuming. I am not unusual at MIT,” Hermus says. Credit: Tony Pulsone

In September 2022, Hermus completed his PhD in mechanical engineering from MIT. He has been an author on seven papers in peer-reviewed journals, three as first author and four of them published when he was an undergraduate. He has won awards for his academics and for his mechanical engineering research and has served as a mentor and an advocate for disability awareness in several different contexts.

His work as a researcher stems directly from his personal experience, Hermus says. As a student in a special education classroom, “I observed assistive technologies — developed by scientists and engineers my friends and I never met — which liberated us. My dream has always been to be one of those engineers.”

Hermus’ work aims to investigate and model human interaction with objects where both substantial motion and force are present. His research has demonstrated that the way humans perform such everyday actions as turning a steering wheel or opening a door is very different from much of robotics. He showed specific patterns exist in the behavior that provide insight into neural control. In 2020, Hermus was the first author on a paper on this topic, which was published in the Journal of Neurophysiology and later won first place in the MIT Mechanical Engineering Research Exhibition. Using this insight, Hermus and his colleagues implemented these strategies on a Kuka LBR iiwa robot to learn about how humans regulate their many degrees of freedom. This work was published in IEEE Transactions on Robotics 2022. More recently, Hermus has collaborated with researchers at the University of Pittsburgh to see if these ideas prove useful in the development of brain computer interfaces — using electrodes implanted in the brain to control a prosthetic robotic arm.

While the hardware of prosthetics and exoskeletons is advancing, Hermus says, there are daunting limitations to the field in the descriptive modeling of human physical behavior, especially during contact with objects. Without these descriptive models, developing generalizable implementations of prosthetics, exoskeletons, and rehabilitation robotics will prove challenging.

“We need competent descriptive models of human physical interaction,” he says.

While earning his master’s and doctoral degrees at MIT, Hermus worked with Neville Hogan, the Sun Jae Professor of Mechanical Engineering, in the Eric P. and Evelyn E. Newman Laboratory for Biomechanics and Human Rehabilitation. Hogan has high praise for the research Hermus has conducted over his six years in the Newman lab.

“James has done superb work for both his master’s and doctoral theses. He tackled a challenging problem and made excellent and timely progress towards its solution. He was a key member of my research group,” Hogan says. “James’ commitment to his research is unquestionably a reflection of his own experience.”

Following postdoctoral research at MIT, where he has also been a part-time lecturer, Hermus is now beginning postdoctoral work with Professor Aude Billard at EPFL in Switzerland, where he hopes to gain experience with learning and optimization methods to further his human motor control research.

Hermus’ enthusiasm for his research is palpable, and his zest for learning and life shines through despite the hurdles his dyslexia presented. He demonstrates a similar kind of excitement for ski-touring and rock-climbing with the MIT Outing Club, working at MakerWorkshop, and being a member of the MechE community.

“MIT is an incredible place. The people in MechE at MIT are extremely passionate and unassuming. I am not unusual at MIT,” he says. “Nearly every person I know well has a unique story with an unconventional path.”

Researchers have come up with an innovative approach to building deformable underwater robots using simple repeating substructures. The team has demonstrated the new system in two different example configurations, one like an eel, pictured here in the MIT tow tank. Credit: Courtesy of the researchers

By David L. Chandler | MIT News Office

Underwater structures that can change their shapes dynamically, the way fish do, push through water much more efficiently than conventional rigid hulls. But constructing deformable devices that can change the curve of their body shapes while maintaining a smooth profile is a long and difficult process. MIT’s RoboTuna, for example, was composed of about 3,000 different parts and took about two years to design and build.

Now, researchers at MIT and their colleagues — including one from the original RoboTuna team — have come up with an innovative approach to building deformable underwater robots, using simple repeating substructures instead of unique components. The team has demonstrated the new system in two different example configurations, one like an eel and the other a wing-like hydrofoil. The principle itself, however, allows for virtually unlimited variations in form and scale, the researchers say.

The work is being reported in the journal Soft Robotics, in a paper by MIT research assistant Alfonso Parra Rubio, professors Michael Triantafyllou and Neil Gershenfeld, and six others.

Existing approaches to soft robotics for marine applications are generally made on small scales, while many useful real-world applications require devices on scales of meters. The new modular system the researchers propose could easily be extended to such sizes and beyond, without requiring the kind of retooling and redesign that would be needed to scale up current systems.

The deformable robots are made with lattice-like pieces, called voxels, that are low density and have high stiffness. The deformable robots are made with lattice-like pieces, called voxels, that are low density and have high stiffness. Credit: Courtesy of the researchers

“Scalability is a strong point for us,” says Parra Rubio. Given the low density and high stiffness of the lattice-like pieces, called voxels, that make up their system, he says, “we have more room to keep scaling up,” whereas most currently used technologies “rely on high-density materials facing drastic problems” in moving to larger sizes.

The individual voxels in the team’s experimental, proof-of-concept devices are mostly hollow structures made up of cast plastic pieces with narrow struts in complex shapes. The box-like shapes are load-bearing in one direction but soft in others, an unusual combination achieved by blending stiff and flexible components in different proportions.

“Treating soft versus hard robotics is a false dichotomy,” Parra Rubio says. “This is something in between, a new way to construct things.” Gershenfeld, head of MIT’s Center for Bits and Atoms, adds that “this is a third way that marries the best elements of both.”

“Smooth flexibility of the body surface allows us to implement flow control that can reduce drag and improve propulsive efficiency, resulting in substantial fuel saving,” says Triantafyllou, who is the Henry L. and Grace Doherty Professor in Ocean Science and Engineering, and was part of the RoboTuna team.

Credit: Courtesy of the researchers.

In one of the devices produced by the team, the voxels are attached end-to-end in a long row to form a meter-long, snake-like structure. The body is made up of four segments, each consisting of five voxels, with an actuator in the center that can pull a wire attached to each of the two voxels on either side, contracting them and causing the structure to bend. The whole structure of 20 units is then covered with a rib-like supporting structure, and then a tight-fitting waterproof neoprene skin. The researchers deployed the structure in an MIT tow tank to show its efficiency in the water, and demonstrated that it was indeed capable of generating forward thrust sufficient to propel itself forward using undulating motions.

“There have been many snake-like robots before,” Gershenfeld says. “But they’re generally made of bespoke components, as opposed to these simple building blocks that are scalable.”

For example, Parra Rubio says, a snake-like robot built by NASA was made up of thousands of unique pieces, whereas for this group’s snake, “we show that there are some 60 pieces.” And compared to the two years spent designing and building the MIT RoboTuna, this device was assembled in about two days, he says.

The individual voxels are mostly hollow structures made up of cast plastic pieces with narrow struts in complex shapes. Credit: Courtesy of the researchers

The other device they demonstrated is a wing-like shape, or hydrofoil, made up of an array of the same voxels but able to change its profile shape and therefore control the lift-to-drag ratio and other properties of the wing. Such wing-like shapes could be used for a variety of purposes, ranging from generating power from waves to helping to improve the efficiency of ship hulls — a pressing demand, as shipping is a significant source of carbon emissions.

The wing shape, unlike the snake, is covered in an array of scale-like overlapping tiles, designed to press down on each other to maintain a waterproof seal even as the wing changes its curvature. One possible application might be in some kind of addition to a ship’s hull profile that could reduce the formation of drag-inducing eddies and thus improve its overall efficiency, a possibility that the team is exploring with collaborators in the shipping industry.

The team also created a wing-like hydrofoil. Credit: Courtesy of the researchers

Ultimately, the concept might be applied to a whale-like submersible craft, using its morphable body shape to create propulsion. Such a craft that could evade bad weather by staying below the surface, but without the noise and turbulence of conventional propulsion. The concept could also be applied to parts of other vessels, such as racing yachts, where having a keel or a rudder that could curve gently during a turn instead of remaining straight could provide an extra edge. “Instead of being rigid or just having a flap, if you can actually curve the way fish do, you can morph your way around the turn much more efficiently,” Gershenfeld says.

The research team included Dixia Fan of the Westlake University in China; Benjamin Jenett SM ’15, PhD ’ 20 of Discrete Lattice Industries; Jose del Aguila Ferrandis, Amira Abdel-Rahman and David Preiss of MIT; and Filippos Tourlomousis of the Demokritos Research Center of Greece. The work was supported by the U.S. Army Research Lab, CBA Consortia funding, and the MIT Sea Grant Program.

• PAPER – Modular Morphing Lattices for Large-Scale Underwater Continuum Robotic Structures. Alfonso Parra Rubio, Dixia Fan, Benjamin Jenett, José del Águila Ferrandis, Filippos Tourlomousis, Amira Abdel-Rahman, David Preiss, Michael Triantafyllou, and Neil Gershenfeld. Soft Robotics (2023).

Fadel Adib, associate professor in the Department of Electrical Engineering and Computer Science and the Media Lab, seeks to develop wireless technology that can sense the physical world in ways that were not possible before. Image: Adam Glanzman

By Adam Zewe | MIT News Office

Fadel Adib never expected that science would get him into the White House, but in August 2015 the MIT graduate student found himself demonstrating his research to the president of the United States.

Adib, fellow grad student Zachary Kabelac, and their advisor, Dina Katabi, showcased a wireless device that uses Wi-Fi signals to track an individual’s movements.

As President Barack Obama looked on, Adib walked back and forth across the floor of the Oval Office, collapsed onto the carpet to demonstrate the device’s ability to monitor falls, and then sat still so Katabi could explain to the president how the device was measuring his breathing and heart rate.

“Zach started laughing because he could see that my heart rate was 110 as I was demoing the device to the president. I was stressed about it, but it was so exciting. I had poured a lot of blood, sweat, and tears into that project,” Adib recalls.

For Adib, the White House demo was an unexpected — and unforgettable — culmination of a research project he had launched four years earlier when he began his graduate training at MIT. Now, as a newly tenured associate professor in the Department of Electrical Engineering and Computer Science and the Media Lab, he keeps building off that work. Adib, the Doherty Chair of Ocean Utilization, seeks to develop wireless technology that can sense the physical world in ways that were not possible before.

In his Signal Kinetics group, Adib and his students apply knowledge and creativity to global problems like climate change and access to health care. They are using wireless devices for contactless physiological sensing, such as measuring someone’s stress level using Wi-Fi signals. The team is also developing battery-free underwater cameras that could explore uncharted regions of the oceans, tracking pollution and the effects of climate change. And they are combining computer vision and radio frequency identification (RFID) technology to build robots that find hidden items, to streamline factory and warehouse operations and, ultimately, alleviate supply chain bottlenecks.

While these areas may seem quite different, each time they launch a new project, the researchers uncover common threads that tie the disciplines together, Adib says.

“When we operate in a new field, we get to learn. Every time you are at a new boundary, in a sense you are also like a kid, trying to understand these different languages, bring them together, and invent something,” he says.

A science-minded child

A love of learning has driven Adib since he was a young child growing up in Tripoli on the coast of Lebanon. He had been interested in math and science for as long as he could remember, and had boundless energy and insatiable curiosity as a child.

“When my mother wanted me to slow down, she would give me a puzzle to solve,” he recalls.

By the time Adib started college at the American University of Beirut, he knew he wanted to study computer engineering and had his sights set on MIT for graduate school.

Seeking to kick-start his future studies, Adib reached out to several MIT faculty members to ask about summer internships. He received a response from the first person he contacted. Katabi, the Thuan and Nicole Pham Professor in the Department of Electrical Engineering and Computer Science (EECS), and a principal investigator in the Computer Science and Artificial Intelligence Laboratory (CSAIL) and the MIT Jameel Clinic, interviewed him and accepted him for a position. He immersed himself in the lab work and, as the end of summer approached, Katabi encouraged him to apply for grad school at MIT and join her lab.

“To me, that was a shock because I felt this imposter syndrome. I thought I was moving like a turtle with my research, but I did not realize that with research itself, because you are at the boundary of human knowledge, you are expected to progress iteratively and slowly,” he says.

As an MIT grad student, he began contributing to a number of projects. But his passion for invention pushed him to embark into unexplored territory. Adib had an idea: Could he use Wi-Fi to see through walls?

“It was a crazy idea at the time, but my advisor let me work on it, even though it was not something the group had been working on at all before. We both thought it was an exciting idea,” he says.

As Wi-Fi signals travel in space, a small part of the signal passes through walls — the same way light passes through windows — and is then reflected by whatever is on the other side. Adib wanted to use these signals to “see” what people on the other side of a wall were doing.

Discovering new applications

There were a lot of ups and downs (“I’d say many more downs than ups at the beginning”), but Adib made progress. First, he and his teammates were able to detect people on the other side of a wall, then they could determine their exact location. Almost by accident, he discovered that the device could be used to monitor someone’s breathing.

“I remember we were nearing a deadline and my friend Zach and I were working on the device, using it to track people on the other side of the wall. I asked him to hold still, and then I started to see him appearing and disappearing over and over again. I thought, could this be his breathing?” Adib says.

Eventually, they enabled their Wi-Fi device to monitor heart rate and other vital signs. The technology was spun out into a startup, which presented Adib with a conundrum once he finished his PhD — whether to join the startup or pursue a career in academia.

He decided to become a professor because he wanted to dig deeper into the realm of invention. But after living through the winter of 2014-2015, when nearly 109 inches of snow fell on Boston (a record), Adib was ready for a change of scenery and a warmer climate. He applied to universities all over the United States, and while he had some tempting offers, Adib ultimately realized he didn’t want to leave MIT. He joined the MIT faculty as an assistant professor in 2016 and was named associate professor in 2020.

“When I first came here as an intern, even though I was thousands of miles from Lebanon, I felt at home. And the reason for that was the people. This geekiness — this embrace of intellect — that is something I find to be beautiful about MIT,” he says.

He’s thrilled to work with brilliant people who are also passionate about problem-solving. The members of his research group are diverse, and they each bring unique perspectives to the table, which Adib says is vital to encourage the intellectual back-and-forth that drives their work.

Diving into a new project

For Adib, research is exploration. Take his work on oceans, for instance. He wanted to make an impact on climate change, and after exploring the problem, he and his students decided to build a battery-free underwater camera.

Adib learned that the ocean, which covers 70 percent of the planet, plays the single largest role in the Earth’s climate system. Yet more than 95 percent of it remains unexplored. That seemed like a problem the Signal Kinetics group could help solve, he says.

But diving into this research area was no easy task. Adib studies Wi-Fi systems, but Wi-Fi does not work underwater. And it is difficult to recharge a battery once it is deployed in the ocean, making it hard to build an autonomous underwater robot that can do large-scale sensing.

So, the team borrowed from other disciplines, building an underwater camera that uses acoustics to power its equipment and capture and transmit images.

“We had to use piezoelectric materials, which come from materials science, to develop transducers, which come from oceanography, and then on top of that we had to marry these things with technology from RF known as backscatter,” he says. “The biggest challenge becomes getting these things to gel together. How do you decode these languages across fields?”

It’s a challenge that continues to motivate Adib as he and his students tackle problems that are too big for one discipline.

He’s excited by the possibility of using his undersea wireless imaging technology to explore distant planets. These same tools could also enhance aquaculture, which could help eradicate food insecurity, or support other emerging industries.

To Adib, the possibilities seem endless.

“With each project, we discover something new, and that opens up a whole new world to explore. The biggest driver of our work in the future will be what we think is impossible, but that we could make possible,” he says.

Shriya Srinivasan as a dancer and researcher | Snapshots taken from ‘Connecting the human body to the outside world’ video on YouTube

“The human body is just engineered so beautifully,” says Shriya Srinivasan PhD ’20, a research affiliate at MIT’s Koch Institute for Integrative Cancer Research, a junior fellow at the Society of Fellows at Harvard University, and former doctoral student in the Harvard-MIT Program in Health Sciences and Technology.

Both a biomedical engineer and a dancer, Srinivasan is dedicated to investigating the body’s movements and sensations. As a PhD student she worked in Media Lab Professor Hugh Herr’s Biomechatronics Group on a system that helps patients with amputation feel what their prostheses are feeling and send feedback from the device to the body. She has also studied the south Indian classical dance form Bharathanatyam for 22 years and co-directs the Anubhava Dance Company.

“The kind of relief and sense of fulfillment I get from the arts is very different from what I get from research and science,” she says. “I find that research often nourishes my intellectual curiosity, and the arts are helping to build that emotional and spiritual growth. But in both worlds, I’m thinking about how we create a sense of feeling, how we control emotion and your physiological response. That’s really beautiful to me.”

Video by: Jason Kimball/MIT News | 5 minutes 34 seconds.

“Learning about the social implications of the technology you’re working on is really important,” says senior Austen Roberson. Photo: Jodi Hilton

By Laura Rosado | MIT News correspondent

Austen Roberson’s favorite class at MIT is 2.S007 (Design and Manufacturing I-Autonomous Machines), in which students design, build, and program a fully autonomous robot to accomplish tasks laid out on a themed game board.

“The best thing about that class is everyone had a different idea,” says Roberson. “We all had the same game board and the same instructions given to us, but the robots that came out of people’s minds were so different.”

The game board was Mars-themed, with a model shuttle that could be lifted to score points. Roberson’s robot, nicknamed Tank Evans after a character from the movie “Surf’s Up,” employed a clever strategy to accomplish this task. Instead of spinning the gears that would raise the entire mechanism, Roberson realized a claw gripper could wrap around the outside of the shuttle and lift it manually.

“That wasn’t the intended way,” says Roberson, but his outside-of-the-box strategy ending up winning him the competition at the conclusion of the class, which was part of the New Engineering Education Transformation (NEET) program. “It was a really great class for me. I get a lot of gratification out of building something with my hands and then using my programming and problem-solving skills to make it move.”

Roberson, a senior, is majoring in aerospace engineering with a minor in computer science. As his winning robot demonstrates, he thrives at the intersection of both fields. He references the Mars Curiosity Rover as the type of project that inspires him; he even keeps a Lego model of Curiosity on his desk. 

“You really have to trust that the hardware you’ve made is up to the task, but you also have to trust your software equally as much,” says Roberson, referring to the challenges of operating a rover from millions of miles away. “Is the robot going to continue to function after we’ve put it into space? Both of those things have to come together in such a perfect way to make this stuff work.”

Outside of formal classwork, Roberson has pursued multiple research opportunities at MIT that blend his academic interests. He’s worked on satellite situational awareness with the Space Systems Laboratory, tested drone flight in different environments with the Aerospace Controls Laboratory, and is currently working on zero-shot machine learning for anomaly detection in big datasets with the Mechatronics Research Laboratory.

“Whether that be space exploration or something else, all I can hope for is that I’m making an impact, and that I’m making a difference in people’s lives,” says Roberson. Photo: Jodi Hilton

Even while tackling these challenging technical problems head-on, Roberson is also actively thinking about the social impact of his work. He takes classes in the Program on Science, Technology, and Society, which has taught him not only how societal change throughout history has been driven by technological advancements, but also how to be a thoughtful engineer in his own career.

“Learning about the social implications of the technology you’re working on is really important,” says Roberson, acknowledging that his work in automation and machine learning needs to address these questions. “Sometimes, we get caught up in technology for technology’s sake. How can we take these same concepts and bring them to people to help in a tangible, physical way? How have we come together as a scientific community to really affect social change, and what can we do in the future to continue affecting that social change?”

Roberson is already working through what these questions mean for him personally. He’s been a member of the National Society of Black Engineers (NSBE) throughout his entire college experience, which includes serving on the executive board for two years. He’s helped to organize workshops focused on everything from interview preparation to financial literacy, as well as social events to build community among members.

“The mission of the organization is to increase the number of culturally responsible Black engineers that excel academically, succeed professionally, and positively impact the community,” says Roberson. “My goal with NSBE was to be able to provide a resource to help everybody get to where they wanted to be, to be the vehicle to really push people to be their best, and to provide the resources that people needed and wanted to advance themselves professionally.”

In fact, one of his most memorable MIT experiences is the first conference he attended as a member of NSBE.

“Being able to see all different these people from all of these different schools able to come together as a family and just talk to each other, it’s a very rewarding experience,” Roberson says. “It’s important to be able to surround yourself with people who have similar professional goals and share similar backgrounds and experiences with you. It’s definitely the proudest I’ve been of any club at MIT.”

Looking toward his own career, Roberson wants to find a way to work on fast-paced, cutting-edge technologies that move society forward in a positive way.

“Whether that be space exploration or something else, all I can hope for is that I’m making an impact, and that I’m making a difference in people’s lives,” says Roberson. “I think learning about space is learning about ourselves as well. The more you can learn about the stuff that’s out there, you can take those lessons to reflect on what’s down here as well.”

A newly published paper quantifies the extent to which automation has contributed to income inequality in the U.S., simply by replacing workers with technology — whether self-checkout machines, call-center systems, assembly-line technology, or other devices. Image: Jose-Luis Olivares, MIT

By Peter Dizikes

When you use self-checkout machines in supermarkets and drugstores, you are probably not — with all due respect — doing a better job of bagging your purchases than checkout clerks once did. Automation just makes bagging less expensive for large retail chains.

“If you introduce self-checkout kiosks, it’s not going to change productivity all that much,” says MIT economist Daron Acemoglu. However, in terms of lost wages for employees, he adds, “It’s going to have fairly large distributional effects, especially for low-skill service workers. It’s a labor-shifting device, rather than a productivity-increasing device.”

A newly published study co-authored by Acemoglu quantifies the extent to which automation has contributed to income inequality in the U.S., simply by replacing workers with technology — whether self-checkout machines, call-center systems, assembly-line technology, or other devices. Over the last four decades, the income gap between more- and less-educated workers has grown significantly; the study finds that automation accounts for more than half of that increase.

“This single one variable … explains 50 to 70 percent of the changes or variation between group inequality from 1980 to about 2016,” Acemoglu says.

The paper, “Tasks, Automation, and the Rise in U.S. Wage Inequality,” is being published in Econometrica. The authors are Acemoglu, who is an Institute Professor at MIT, and Pascual Restrepo PhD ’16, an assistant professor of economics at Boston University.

So much “so-so automation”

Since 1980 in the U.S., inflation-adjusted incomes of those with college and postgraduate degrees have risen substantially, while inflation-adjusted earnings of men without high school degrees has dropped by 15 percent.

How much of this change is due to automation? Growing income inequality could also stem from, among other things, the declining prevalence of labor unions, market concentration begetting a lack of competition for labor, or other types of technological change.

To conduct the study, Acemoglu and Restrepo used U.S. Bureau of Economic Analysis statistics on the extent to which human labor was used in 49 industries from 1987 to 2016, as well as data on machinery and software adopted in that time. The scholars also used data they had previously compiled about the adoption of robots in the U.S. from 1993 to 2014. In previous studies, Acemoglu and Restrepo have found that robots have by themselves replaced a substantial number of workers in the U.S., helped some firms dominate their industries, and contributed to inequality.

At the same time, the scholars used U.S. Census Bureau metrics, including its American Community Survey data, to track worker outcomes during this time for roughly 500 demographic subgroups, broken out by gender, education, age, race and ethnicity, and immigration status, while looking at employment, inflation-adjusted hourly wages, and more, from 1980 to 2016. By examining the links between changes in business practices alongside changes in labor market outcomes, the study can estimate what impact automation has had on workers.

Ultimately, Acemoglu and Restrepo conclude that the effects have been profound. Since 1980, for instance, they estimate that automation has reduced the wages of men without a high school degree by 8.8 percent and women without a high school degree by 2.3 percent, adjusted for inflation. 

A central conceptual point, Acemoglu says, is that automation should be regarded differently from other forms of innovation, with its own distinct effects in workplaces, and not just lumped in as part of a broader trend toward the implementation of technology in everyday life generally.

Consider again those self-checkout kiosks. Acemoglu calls these types of tools “so-so technology,” or “so-so automation,” because of the tradeoffs they contain: Such innovations are good for the corporate bottom line, bad for service-industry employees, and not hugely important in terms of overall productivity gains, the real marker of an innovation that may improve our overall quality of life.

“Technological change that creates or increases industry productivity, or productivity of one type of labor, creates [those] large productivity gains but does not have huge distributional effects,” Acemoglu says. “In contrast, automation creates very large distributional effects and may not have big productivity effects.”

A new perspective on the big picture

The results occupy a distinctive place in the literature on automation and jobs. Some popular accounts of technology have forecast a near-total wipeout of jobs in the future. Alternately, many scholars have developed a more nuanced picture, in which technology disproportionately benefits highly educated workers but also produces significant complementarities between high-tech tools and labor.

The current study differs at least by degree with this latter picture, presenting a more stark outlook in which automation reduces earnings power for workers and potentially reduces the extent to which policy solutions — more bargaining power for workers, less market concentration — could mitigate the detrimental effects of automation upon wages.

“These are controversial findings in the sense that they imply a much bigger effect for automation than anyone else has thought, and they also imply less explanatory power for other [factors],” Acemoglu says.

Still, he adds, in the effort to identify drivers of income inequality, the study “does not obviate other nontechnological theories completely. Moreover, the pace of automation is often influenced by various institutional factors, including labor’s bargaining power.”

Labor economists say the study is an important addition to the literature on automation, work, and inequality, and should be reckoned with in future discussions of these issues.

“Acemoglu and Restrepo’s paper proposes an elegant new theoretical framework for understanding the potentially complex effects of technical change on the aggregate structure of wages,” says Patrick Kline, a professor of economics at the University of California, Berkeley. “Their empirical finding that automation has been the dominant factor driving U.S. wage dispersion since 1980 is intriguing and seems certain to reignite debate over the relative roles of technical change and labor market institutions in generating wage inequality.”

For their part, in the paper Acemoglu and Restrepo identify multiple directions for future research. That includes investigating the reaction over time by both business and labor to the increase in automation; the quantitative effects of technologies that do create jobs; and the industry competition between firms that quickly adopted automation and those that did not.

The research was supported in part by Google, the Hewlett Foundation, Microsoft, the National Science Foundation, Schmidt Sciences, the Sloan Foundation, and the Smith Richardson Foundation.

• PAPER – Tasks, Automation, and the Rise in U.S. Wage Inequality. Daron Acemoglu, and Pascual Restrepo. Econometrica, 90: 1973-2016. https://doi.org/10.3982/ECTA19815

Researchers at MIT have made significant steps toward creating robots that could practically and economically assemble nearly anything, including things much larger than themselves, from vehicles to buildings to larger robots. The new system involves large, usable structures built from an array of tiny identical subunits called voxels (the volumetric equivalent of a 2-D pixel). Courtesy of the researchers.

By David L. Chandler

Researchers at MIT have made significant steps toward creating robots that could practically and economically assemble nearly anything, including things much larger than themselves, from vehicles to buildings to larger robots.

The new work, from MIT’s Center for Bits and Atoms (CBA), builds on years of research, including recent studies demonstrating that objects such as a deformable airplane wing and a functional racing car could be assembled from tiny identical lightweight pieces — and that robotic devices could be built to carry out some of this assembly work. Now, the team has shown that both the assembler bots and the components of the structure being built can all be made of the same subunits, and the robots can move independently in large numbers to accomplish large-scale assemblies quickly.

The new work is reported in the journal Nature Communications Engineering, in a paper by CBA doctoral student Amira Abdel-Rahman, Professor and CBA Director Neil Gershenfeld, and three others.

A fully autonomous self-replicating robot assembly system capable of both assembling larger structures, including larger robots, and planning the best construction sequence is still years away, Gershenfeld says. But the new work makes important strides toward that goal, including working out the complex tasks of when to build more robots and how big to make them, as well as how to organize swarms of bots of different sizes to build a structure efficiently without crashing into each other.

As in previous experiments, the new system involves large, usable structures built from an array of tiny identical subunits called voxels (the volumetric equivalent of a 2-D pixel). But while earlier voxels were purely mechanical structural pieces, the team has now developed complex voxels that each can carry both power and data from one unit to the next. This could enable the building of structures that can not only bear loads but also carry out work, such as lifting, moving and manipulating materials — including the voxels themselves.

“When we’re building these structures, you have to build in intelligence,” Gershenfeld says. While earlier versions of assembler bots were connected by bundles of wires to their power source and control systems, “what emerged was the idea of structural electronics — of making voxels that transmit power and data as well as force.” Looking at the new system in operation, he points out, “There’s no wires. There’s just the structure.”

The robots themselves consist of a string of several voxels joined end-to-end. These can grab another voxel using attachment points on one end, then move inchworm-like to the desired position, where the voxel can be attached to the growing structure and released there.

Gershenfeld explains that while the earlier system demonstrated by members of his group could in principle build arbitrarily large structures, as the size of those structures reached a certain point in relation to the size of the assembler robot, the process would become increasingly inefficient because of the ever-longer paths each bot would have to travel to bring each piece to its destination. At that point, with the new system, the bots could decide it was time to build a larger version of themselves that could reach longer distances and reduce the travel time. An even bigger structure might require yet another such step, with the new larger robots creating yet larger ones, while parts of a structure that include lots of fine detail may require more of the smallest robots.

Credit: Amira Abdel-Rahman/MIT Center for Bits and Atoms

As these robotic devices work on assembling something, Abdel-Rahman says, they face choices at every step along the way: “It could build a structure, or it could build another robot of the same size, or it could build a bigger robot.” Part of the work the researchers have been focusing on is creating the algorithms for such decision-making.

“For example, if you want to build a cone or a half-sphere,” she says, “how do you start the path planning, and how do you divide this shape” into different areas that different bots can work on? The software they developed allows someone to input a shape and get an output that shows where to place the first block, and each one after that, based on the distances that need to be traversed.

There are thousands of papers published on route-planning for robots, Gershenfeld says. “But the step after that, of the robot having to make the decision to build another robot or a different kind of robot — that’s new. There’s really nothing prior on that.”

While the experimental system can carry out the assembly and includes the power and data links, in the current versions the connectors between the tiny subunits are not strong enough to bear the necessary loads. The team, including graduate student Miana Smith, is now focusing on developing stronger connectors. “These robots can walk and can place parts,” Gershenfeld says, “but we are almost — but not quite — at the point where one of these robots makes another one and it walks away. And that’s down to fine-tuning of things, like the force of actuators and the strength of joints. … But it’s far enough along that these are the parts that will lead to it.”

Ultimately, such systems might be used to construct a wide variety of large, high-value structures. For example, currently the way airplanes are built involves huge factories with gantries much larger than the components they build, and then “when you make a jumbo jet, you need jumbo jets to carry the parts of the jumbo jet to make it,” Gershenfeld says. With a system like this built up from tiny components assembled by tiny robots, “The final assembly of the airplane is the only assembly.”

Similarly, in producing a new car, “you can spend a year on tooling” before the first car gets actually built, he says. The new system would bypass that whole process. Such potential efficiencies are why Gershenfeld and his students have been working closely with car companies, aviation companies, and NASA. But even the relatively low-tech building construction industry could potentially also benefit.

While there has been increasing interest in 3-D-printed houses, today those require printing machinery as large or larger than the house being built. Again, the potential for such structures to instead be assembled by swarms of tiny robots could provide benefits. And the Defense Advanced Research Projects Agency is also interested in the work for the possibility of building structures for coastal protection against erosion and sea level rise.

The new study shows that both the assembler bots and the components of the structure being built can all be made of the same subunits, and the robots can move independently in large numbers to accomplish large-scale assemblies quickly. Courtesy of the researchers.

Aaron Becker, an associate professor of electrical and computer engineering at the University of Houston, who was not associated with this research, calls this paper “a home run — [offering] an innovative hardware system, a new way to think about scaling a swarm, and rigorous algorithms.”

Becker adds: “This paper examines a critical area of reconfigurable systems: how to quickly scale up a robotic workforce and use it to efficiently assemble materials into a desired structure. … This is the first work I’ve seen that attacks the problem from a radically new perspective — using a raw set of robot parts to build a suite of robots whose sizes are optimized to build the desired structure (and other robots) as fast as possible.”

The research team also included MIT-CBA student Benjamin Jenett and Christopher Cameron, who is now at the U.S. Army Research Laboratory. The work was supported by NASA, the U.S. Army Research Laboratory, and CBA consortia funding.

• PAPER – Self-replicating hierarchical modular robotic swarms. Amira Abdel-Rahman, Christopher Cameron, Benjamin Jenett, Miana Smith, and Neil Gershenfeld. Commun Eng 1, 35 (2022). https://doi.org/10.1038/s44172-022-00034-3

A small, bead-like magnet used in a new approach to measuring muscle position. Image: Courtesy of the researchers

By Anne Trafton | MIT News Office

Using a simple set of magnets, MIT researchers have come up with a sophisticated way to monitor muscle movements, which they hope will make it easier for people with amputations to control their prosthetic limbs.

In a new pair of papers, the researchers demonstrated the accuracy and safety of their magnet-based system, which can track the length of muscles during movement. The studies, performed in animals, offer hope that this strategy could be used to help people with prosthetic devices control them in a way that more closely mimics natural limb movement.

“These recent results demonstrate that this tool can be used outside the lab to track muscle movement during natural activity, and they also suggest that the magnetic implants are stable and biocompatible and that they don’t cause discomfort,” says Cameron Taylor, an MIT research scientist and co-lead author of both papers.

In one of the studies, the researchers showed that they could accurately measure the lengths of turkeys’ calf muscles as the birds ran, jumped, and performed other natural movements. In the other study, they showed that the small magnetic beads used for the measurements do not cause inflammation or other adverse effects when implanted in muscle.

“I am very excited for the clinical potential of this new technology to improve the control and efficacy of bionic limbs for persons with limb-loss,” says Hugh Herr, a professor of media arts and sciences, co-director of the K. Lisa Yang Center for Bionics at MIT, and an associate member of MIT’s McGovern Institute for Brain Research.

Herr is a senior author of both papers, which appear in the journal Frontiers in Bioengineering and Biotechnology. Thomas Roberts, a professor of ecology, evolution, and organismal biology at Brown University, is a senior author of the measurement study.

Tracking movement

Currently, powered prosthetic limbs are usually controlled using an approach known as surface electromyography (EMG). Electrodes attached to the surface of the skin or surgically implanted in the residual muscle of the amputated limb measure electrical signals from a person’s muscles, which are fed into the prosthesis to help it move the way the person wearing the limb intends.

However, that approach does not take into account any information about the muscle length or velocity, which could help to make the prosthetic movements more accurate.

Several years ago, the MIT team began working on a novel way to perform those kinds of muscle measurements, using an approach that they call magnetomicrometry. This strategy takes advantage of the permanent magnetic fields surrounding small beads implanted in a muscle. Using a credit-card-sized, compass-like sensor attached to the outside of the body, their system can track the distances between the two magnets. When a muscle contracts, the magnets move closer together, and when it flexes, they move further apart.

The new muscle measuring approach takes advantage of the magnetic attraction between two small beads implanted in a muscle. Using a small sensor attached to the outside of the body, the system can track the distances between the two magnets as the muscle contracts and flexes. Image: Courtesy of the researchers

In a study published last year, the researchers showed that this system could be used to accurately measure small ankle movements when the beads were implanted in the calf muscles of turkeys. In one of the new studies, the researchers set out to see if the system could make accurate measurements during more natural movements in a nonlaboratory setting.

To do that, they created an obstacle course of ramps for the turkeys to climb and boxes for them to jump on and off of. The researchers used their magnetic sensor to track muscle movements during these activities, and found that the system could calculate muscle lengths in less than a millisecond.

They also compared their data to measurements taken using a more traditional approach known as fluoromicrometry, a type of X-ray technology that requires much larger equipment than magnetomicrometry. The magnetomicrometry measurements varied from those generated by fluoromicrometry by less than a millimeter, on average.

“We’re able to provide the muscle-length tracking functionality of the room-sized X-ray equipment using a much smaller, portable package, and we’re able to collect the data continuously instead of being limited to the 10-second bursts that fluoromicrometry is limited to,” Taylor says.

Seong Ho Yeon, an MIT graduate student, is also a co-lead author of the measurement study. Other authors include MIT Research Support Associate Ellen Clarrissimeaux and former Brown University postdoc Mary Kate O’Donnell.

Biocompatibility

In the second paper, the researchers focused on the biocompatibility of the implants. They found that the magnets did not generate tissue scarring, inflammation, or other harmful effects. They also showed that the implanted magnets did not alter the turkeys’ gaits, suggesting they did not produce discomfort. William Clark, a postdoc at Brown, is the co-lead author of the biocompatibility study.

The researchers also showed that the implants remained stable for eight months, the length of the study, and did not migrate toward each other, as long as they were implanted at least 3 centimeters apart. The researchers envision that the beads, which consist of a magnetic core coated with gold and a polymer called Parylene, could remain in tissue indefinitely once implanted.

“Magnets don’t require an external power source, and after implanting them into the muscle, they can maintain the full strength of their magnetic field throughout the lifetime of the patient,” Taylor says.

The researchers are now planning to seek FDA approval to test the system in people with prosthetic limbs. They hope to use the sensor to control prostheses similar to the way surface EMG is used now: Measurements regarding the length of muscles will be fed into the control system of a prosthesis to help guide it to the position that the wearer intends.

“The place where this technology fills a need is in communicating those muscle lengths and velocities to a wearable robot, so that the robot can perform in a way that works in tandem with the human,” Taylor says. “We hope that magnetomicrometry will enable a person to control a wearable robot with the same comfort level and the same ease as someone would control their own limb.”

In addition to prosthetic limbs, those wearable robots could include robotic exoskeletons, which are worn outside the body to help people move their legs or arms more easily.

The research was funded by the Salah Foundation, the K. Lisa Yang Center for Bionics at MIT, the MIT Media Lab Consortia, the National Institutes of Health, and the National Science Foundation.

• PAPERS
• Untethered muscle tracking using magnetomicrometry. Cameron R. Taylor, Seong Ho Yeon, William H. Clark, Ellen G. Clarrissimeaux, Mary Kate O’Donnell, Thomas J. Roberts, and Hugh M. Herr. Front. Bioeng. Biotechnol., 25. https://doi.org/10.3389/fbioe.2022.1010275




• Clinical viability of magnetic bead implants in muscle. Cameron R. Taylor, William H. Clark, Ellen G. Clarrissimeaux, Seong Ho Yeon, Matthew J. Carty, Stuart R. Lipsitz, Roderick T. Bronson, Thomas J. Roberts, and Hugh M. Herr. Front. Bioeng. Biotechnol., 25. https://doi.org/10.3389/fbioe.2022.1010276

With just a random disturbance that energizes the cubes, they selectively self-assemble into a larger block. Photos courtesy of MIT CSAIL.

By Rachel Gordon | MIT CSAIL

While automated manufacturing is ubiquitous today, it was once a nascent field birthed by inventors such as Oliver Evans, who is credited with creating the first fully automated industrial process, in flour mill he built and gradually automated in the late 1700s. The processes for creating automated structures or machines are still very top-down, requiring humans, factories, or robots to do the assembling and making. 

However, the way nature does assembly is ubiquitously bottom-up; animals and plants are self-assembled at a cellular level, relying on proteins to self-fold into target geometries that encode all the different functions that keep us ticking. For a more bio-inspired, bottom-up approach to assembly, then, human-architected materials need to do better on their own. Making them scalable, selective, and reprogrammable in a way that could mimic nature’s versatility means some teething problems, though. 

Now, researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have attempted to get over these growing pains with a new method: introducing magnetically reprogrammable materials that they coat different parts with — like robotic cubes — to let them self-assemble. Key to their process is a way to make these magnetic programs highly selective about what they connect with, enabling robust self-assembly into specific shapes and chosen configurations. 

The soft magnetic material coating the researchers used, sourced from inexpensive refrigerator magnets, endows each of the cubes they built with a magnetic signature on each of its faces. The signatures ensure that each face is selectively attractive to only one other face from all the other cubes, in both translation and rotation. All of the cubes — which run for about 23 cents — can be magnetically programmed at a very fine resolution. Once they’re tossed into a water tank (they used eight cubes for a demo), with a totally random disturbance — you could even just shake them in a box — they’ll bump into each other. If they meet the wrong mate, they’ll drop off, but if they find their suitable mate, they’ll attach. 

An analogy would be to think of a set of furniture parts that you need to assemble into a chair. Traditionally, you’d need a set of instructions to manually assemble parts into a chair (a top-down approach), but using the researchers’ method, these same parts, once programmed magnetically, would self-assemble into the chair using just a random disturbance that makes them collide. Without the signatures they generate, however, the chair would assemble with its legs in the wrong places.

“This work is a step forward in terms of the resolution, cost, and efficacy with which we can self-assemble particular structures,” says Martin Nisser, a PhD student in MIT’s Department of Electrical Engineering and Computer Science (EECS), an affiliate of CSAIL, and the lead author on a new paper about the system. “Prior work in self-assembly has typically required individual parts to be geometrically dissimilar, just like puzzle pieces, which requires individual fabrication of all the parts. Using magnetic programs, however, we can bulk-manufacture homogeneous parts and program them to acquire specific target structures, and importantly, reprogram them to acquire new shapes later on without having to refabricate the parts anew.” 

Using the team’s magnetic plotting machine, one can stick a cube back in the plotter and reprogram it. Every time the plotter touches the material, it creates either a “north”- or “south”-oriented magnetic pixel on the cube’s soft magnetic coating, letting the cubes be repurposed to assemble new target shapes when required. Before plotting, a search algorithm checks each signature for mutual compatibility with all previously programmed signatures to ensure they are selective enough for successful self-assembly.

With self-assembly, you can go the passive or active route. With active assembly, robotic parts modulate their behavior online to locate, position, and bond to their neighbors, and each module needs to be embedded with hardware for the computation, sensing, and actuation required to self-assemble themselves. What’s more, a human or computer is needed in the loop to actively control the actuators embedded in each part to make it move. While active assembly has been successful in reconfiguring a variety of robotic systems, the cost and complexity of the electronics and actuators have been a significant barrier to scaling self-assembling hardware up in numbers and down in size. 

With passive methods like these researchers’, there’s no need for embedded actuation and control.

Once programmed and set free under a random disturbance that gives them the energy to collide with one another, they’re on their own to shapeshift, without any guiding intelligence.  

If you want a structure built from hundreds or thousands of parts, like a ladder or bridge, for example, you wouldn’t want to manufacture a million uniquely different parts, or to have to re-manufacture them when you need a second structure assembled.

The trick the team used toward this goal lies in the mathematical description of the magnetic signatures, which describes each signature as a 2D matrix of pixels. These matrices ensure that any magnetically programmed parts that shouldn’t connect will interact to produce just as many pixels in attraction as those in repulsion, letting them remain agnostic to all non-mating parts in both translation and rotation. 

While the system is currently good enough to do self-assembly using a handful of cubes, the team wants to further develop the mathematical descriptions of the signatures. In particular, they want to leverage design heuristics that would enable assembly with very large numbers of cubes, while avoiding computationally expensive search algorithms. 

“Self-assembly processes are ubiquitous in nature, leading to the incredibly complex and beautiful life we see all around us,” says Hod Lipson, the James and Sally Scapa Professor of Innovation at Columbia University, who was not involved in the paper. “But the underpinnings of self-assembly have baffled engineers: How do two proteins destined to join find each other in a soup of billions of other proteins? Lacking the answer, we have been able to self-assemble only relatively simple structures so far, and resort to top-down manufacturing for the rest. This paper goes a long way to answer this question, proposing a new way in which self-assembling building blocks can find each other. Hopefully, this will allow us to begin climbing the ladder of self-assembled complexity.”

Nisser wrote the paper alongside recent EECS graduates Yashaswini Makaram ’21 and Faraz Faruqi SM ’22, both of whom are former CSAIL affiliates; Ryo Suzuki, assistant professor of computer science at the University of Calgary; and MIT associate professor of EECS Stefanie Mueller, who is a CSAIL affiliate. They will present their research at the 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2022).

• PAPER – Selective Self-Assembly using Re-Programmable Magnetic Pixels. Martin Nisser, Yashaswini Makaram, Faraz Faruqi1 Ryo Suzuki, and Stefanie Mueller.

MIT chemical engineers have shown that specialized particles can oscillate together, demonstrating a phenomenon known as emergent behavior. Image: Courtesy of the researchers

By Anne Trafton | MIT News Office

Taking advantage of a phenomenon known as emergent behavior in the microscale, MIT engineers have designed simple microparticles that can collectively generate complex behavior, much the same way that a colony of ants can dig tunnels or collect food.

Working together, the microparticles can generate a beating clock that oscillates at a very low frequency. These oscillations can then be harnessed to power tiny robotic devices, the researchers showed.

“In addition to being interesting from a physics point of view, this behavior can also be translated into an on-board oscillatory electrical signal, which can be very powerful in microrobotic autonomy. There are a lot of electrical components that require such an oscillatory input,” says Jingfan Yang, a recent MIT PhD recipient and one of the lead authors of the new study.

The particles used to create the new oscillator perform a simple chemical reaction that allows the particles to interact with each other through the formation and bursting of tiny gas bubbles. Under the right conditions, these interactions create an oscillator that behaves similar to a ticking clock, beating at intervals of a few seconds.

“We’re trying to look for very simple rules or features that you can encode into relatively simple microrobotic machines, to get them to collectively do very sophisticated tasks,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT.

Strano is the senior author of the new paper, which appears in Nature Communications. Along with Yang, Thomas Berrueta, a Northwestern University graduate student advised by Professor Todd Murphey, is a lead author of the study.

Collective behavior

Demonstrations of emergent behavior can be seen throughout the natural world, where colonies of insects such as ants and bees accomplish feats that a single member of the group would never be able to achieve.

“Ants have minuscule brains and they do very simple cognitive tasks, but collectively they can do amazing things. They can forage for food and build these elaborate tunnel structures,” Strano says. “Physicists and engineers like myself want to understand these rules because it means we can make tiny things that collectively do complex tasks.”

In this study, the researchers wanted to design particles that could generate rhythmic movements, or oscillations, with a very low frequency. Until now, building low-frequency micro-oscillators has required sophisticated electronics that are expensive and difficult to design, or specialized materials with complex chemistries.

The simple particles that the researchers designed for this study are discs as small as 100 microns in diameter. The discs, made from a polymer called SU-8, have a platinum patch that can catalyze the breakdown of hydrogen peroxide into water and oxygen.

When the particles are placed at the surface of a droplet of hydrogen peroxide on a flat surface, they tend to travel to the top of the droplet. At this liquid-air interface, they interact with any other particles found there. Each particle produces its own tiny bubble of oxygen, and when two particles come close enough that their bubbles interact, the bubbles pop, propelling the particles away from each other. Then, they begin forming new bubbles, and the cycle repeats over and over.

“One particle by itself stays still and doesn’t do anything interesting, but through teamwork, they can do something pretty amazing and useful, which is actually a difficult thing to achieve at the microscale,” Yang says.

MIT chemical engineers showed that specialized particles can oscillate together, demonstrating a phenomenon known as emergent behavior. At left, two particles oscillate together, and at right, eight particles. Video courtesy of the researchers.

The researchers found that two particles could make a very reliable oscillator, but as more particles were added, the rhythm would get thrown off. However, if they added one particle that was slightly different from the others, that particle could act as a “leader” that reorganized the other particles back into a rhythmic oscillator.

This leader particle is the same size as the other particles but has a slightly larger platinum patch, which enables it to create a larger oxygen bubble. This allows this particle to move to the center of the group, where it coordinates the oscillations of all of the other particles. Using this approach, the researchers found they could create oscillators containing up to at least 11 particles.

Depending on the number of particles, this oscillator beats at a frequency of about 0.1 to 0.3 hertz, which is on the order of the low-frequency oscillators that govern biological functions such as walking and the beating of the heart.

Oscillating current

The researchers also showed that they could use the rhythmic beating of these particles to generate an oscillating electric current. To do that, they swapped out the platinum catalyst for a fuel cell made of platinum and ruthenium or gold. The mechanical oscillation of the particles rhythmically alters the resistance from one end of the fuel cell to the other, which converts the voltage generated by the fuel cell to an oscillating current.

“Like a dripping faucet, catalytic microdiscs floating at a liquid interface use a chemical reaction to drive the periodic growth and release of gas bubbles. The study shows how these oscillatory dynamics can be harnessed for mechanical actuation and electrochemical signaling relevant to microrobotics,” says Kyle Bishop, a professor of chemical engineering at Columbia University, who was not involved in the study.

Generating an oscillating current instead of a constant one could be useful for applications such as powering tiny robots that can walk. The MIT researchers used this approach to show that they could power a microactuator, which was previously used as legs on a tiny walking robot developed by researchers at Cornell University. The original version was powered by a laser that had to be alternately pointed at each set of legs, to manually oscillate the current. The MIT team showed that the on-board oscillating current generated by their particles could drive the cyclic actuation of the microrobotic leg, using a wire to transfer the current from the particles to the actuator.

“It shows that this mechanical oscillation can become an electrical oscillation, and then that electrical oscillation can actually power activities that a robot would do,” Strano says.

One possible application for this kind of system would be to control swarms of tiny autonomous robots that could be used as sensors to monitor water pollution.

The research was funded in part by the U.S. Army Research Office, the U.S. Department of Energy, and the National Science Foundation.

A new drug capsule developed at MIT can help large proteins such as insulin and small-molecule drugs be absorbed in the digestive tract. Image: Felice Frankel

By Anne Trafton | MIT News Office

One reason that it’s so difficult to deliver large protein drugs orally is that these drugs can’t pass through the mucus barrier that lines the digestive tract. This means that insulin and most other “biologic drugs” — drugs consisting of proteins or nucleic acids — have to be injected or administered in a hospital. 

A new drug capsule developed at MIT may one day be able to replace those injections. The capsule has a robotic cap that spins and tunnels through the mucus barrier when it reaches the small intestine, allowing drugs carried by the capsule to pass into cells lining the intestine.

“By displacing the mucus, we can maximize the dispersion of the drug within a local area and enhance the absorption of both small molecules and macromolecules,” says Giovanni Traverso, the Karl van Tassel Career Development Assistant Professor of Mechanical Engineering at MIT and a gastroenterologist at Brigham and Women’s Hospital.

In a study appearing today in Science Robotics, the researchers demonstrated that they could use this approach to deliver insulin as well as vancomycin, an antibiotic peptide that currently has to be injected.

Shriya Srinivasan, a research affiliate at MIT’s Koch Institute for Integrative Cancer Research and a junior fellow at the Society of Fellows at Harvard University, is the lead author of the study.

Tunneling through

For several years, Traverso’s lab has been developing strategies to deliver protein drugs such as insulin orally. This is a difficult task because protein drugs tend to be broken down in acidic environment of the digestive tract, and they also have difficulty penetrating the mucus barrier that lines the tract.

To overcome those obstacles, Srinivasan came up with the idea of creating a protective capsule that includes a mechanism that can tunnel through mucus, just as tunnel boring machines drill into soil and rock.

“I thought that if we could tunnel through the mucus, then we could deposit the drug directly on the epithelium,” she says. “The idea is that you would ingest this capsule and the outer layer would dissolve in the digestive tract, exposing all these features that start to churn through the mucus and clear it.”

The “RoboCap” capsule, which is about the size of a multivitamin, carries its drug payload in a small reservoir at one end and carries the tunnelling features in its main body and surface. The capsule is coated with gelatin that can be tuned to dissolve at a specific pH.

When the coating dissolves, the change in pH triggers a tiny motor inside the RoboCap capsule to start spinning. This motion helps the capsule to tunnel into the mucus and displace it. The capsule is also coated with small studs that brush mucus away, similar to the action of a toothbrush.

The spinning motion also helps to erode the compartment that carries the drug, which is gradually released into the digestive tract.

“What the RoboCap does is transiently displace the initial mucus barrier and then enhance absorption by maximizing the dispersion of the drug locally,” Traverso says. “By combining all of these elements, we’re really maximizing our capacity to provide the optimal situation for the drug to be absorbed.”

Enhanced delivery

In tests in animals, the researchers used this capsule to deliver either insulin or vancomycin, a large peptide antibiotic that is used to treat a broad range of infections, including skin infections as well as infections affecting orthopedic implants. With the capsule, the researchers found that they could deliver 20 to 40 times more drug than a similar capsule without the tunneling mechanism.

Once the drug is released from the capsule, the capsule itself passes through the digestive tract on its own. The researchers found no sign of inflammation or irritation in the digestive tract after the capsule passed through, and they also observed that the mucus layer reforms within a few hours after being displaced by the capsule.

Another approach that some researchers have used to enhance oral delivery of drugs is to give them along with additional drugs that help them cross through the intestinal tissue. However, these enhancers often only work with certain drugs. Because the MIT team’s new approach relies solely on mechanical disruptions to the mucus barrier, it could potentially be applied to a broader set of drugs, Traverso says.

“Some of the chemical enhancers preferentially work with certain drug molecules,” he says. “Using mechanical methods of administration can potentially enable more drugs to have enhanced absorption.”

While the capsule used in this study released its payload in the small intestine, it could also be used to target the stomach or colon by changing the pH at which the gelatin coating dissolves. The researchers also plan to explore the possibility of delivering other protein drugs such as GLP1 receptor agonist, which is sometimes used to treat type 2 diabetes. The capsules could also be used to deliver topical drugs to treat ulcerative colitis and other inflammatory conditions by maximizing the local concentration of the drugs in the tissue to help treat the inflammation.

The research was funded, in part, by the National Institutes of Health and MIT’s Department of Mechanical Engineering.

Other authors of the paper include Amro Alshareef, Alexandria Hwang, Zilianng Kang, Johannes Kuosmanen, Keiko Ishida, Joshua Jenkins, Sabrina Liu, Wiam Abdalla Mohammed Madani, Jochen Lennerz, Alison Hayward, Josh Morimoto, Nina Fitzgerald, and Robert Langer.

• PAPER – RoboCap: Robotic mucus-clearing capsule for enhanced drug delivery in the gastrointestinal tract. Shriya S. Srinivasan, Amro Alshareef, Alexandria V. Hwang, Ziliang Kang, Johannes Kuosmanen, Keiko Ishida, Joshua Jenkins, Sabrina Liu, Wiam Abdalla Mohammed Madani, Jochen Lennerz, Alison Hayward, Josh Morimoto, Nina Fitzgerald, Robert Langer, and Giovanni Traverso. Science Robotics, vol. 7(70), https://doi.org/10.1126/scirobotics.abp9066