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“‘I had a friend who was a clown. When he died, all his friends went to the funeral in one car.” STEVEN WRIGHT COMEDIAN NOT CLOWN

Yale-led team develops shape-shifting turtle robot

BY ALEX DONG CONTRIBUTING REPORTER

Yale researchers have developed an amphibious robot, complete with shape-shifting limbs that can outperform both legs on land and flippers in water.

From cleaning houses, to managing warehouses, to exploring extreme terrains, the expanding diversity of mobile robotic applications has increased the types of environments that robots must be equipped to face. In their paper published in the journal Nature, a team of Yale researchers developed a robotic turtle with morphing limbs that can travel effectively through disparate natural environments. This study was guided by principal investigator Rebecca Kramer-Bottiglio, the John J. Lee Associate Professor of mechanical engineering and materials science.

“Animals can’t adapt their physiology radically to change the way they move in their environment,” Robert Baines GRD ’23, one of the paper’s co-first authors, and a doctoral researcher in mechanical engineering and materials science, told the News. “What if we could have evolution on demand?”

Most animals and robots alike are specialized to specific environments — their locomotion is designed to be efficient in a particular niche, which comes at the expense of performance in others. For instance, swimming with giraffe legs would prove quite a challenge, while walking with dolphin flippers sounds equally improbable.

To design a robot that can thrive in both worlds, the researchers studied the natural movement mechanisms of terrestrial and aquatic turtles in their respective elements, then integrated them through a design philosophy dubbed “adaptive morphogenesis.”

Morphogenesis alone refers to the emergence of form, or how an animal takes its shape. In natural organisms, this process and the resulting shapes are largely fixed, at least in the window of individual lifetimes. Baines explained that adaptive morphogenesis can be thought of as evolution on demand — changing form in a much shorter timeframe to adapt to the surrounding environment.

Considering the fixed anatomies of animals, using adaptive morphogenesis to change limb shapes and movement patterns would only be possible for an artificial robotic system.

“The main takeaway of the paper isn’t the specific robot embodiment, but rather the design philosophy,” Baines said.

From this design philosophy emerged the Yale researchers’ amphibious robotic turtle (ART), whose morphing limbs are capable of transforming between legs and flippers. Sree Patiballa — the paper’s other co-first author and a former Yale postdoctoral researcher — described the legs as semi-circular in shape with a blunt end, advantageous for bearing the robot turtle’s weight on land. In flipper mode, the limbs become longer and flatter, ideal for propulsion in water.

Designing and constructing ART’s shape-shifting limbs was no easy feat. While many parts like the shell and joints are 3D-printed, the limbs are fabricated with materials that can radically change stiffness by a factor of 450 times.

This variable stiffness allows for a change in limb shape when needed, but remains otherwise rigid and holds the desired shape. Without the ability to change their stiffness, the limbs would either be too rigid to morph, or too flimsy for efficient propulsion in water and weight-bearing on land.

“The variable-stiffness material is thermally responsive and holds the [limb] shape, so we don’t have to keep on pumping the pressure,” Patiballa said. “Once it cools down, we deflate the pressure, and the limb still retains that shape. Once you reheat it, it softens and goes back to the flipper shape.”

In addition to changing limb shapes, ART can also change its movement patterns, or “gaits,” depending on the environment, since the mechanisms of motion are different in water compared to on land. For instance, trying to walk while submerged or paddle on land would prove very difficult. The researchers created the robot for three distinct environ-

COURTESY OF ROBERT BAINES

A group of researchers led by Professor of Mechanical Engineering and Materials Science Rebecca Kramer-Bottiglio have developed an amphibious robotic turtle that can adapt to disparate environments.

ments: land, water and the transition zone in between.

Using twelve motors in ART’s shoulder joints, three per limb, the researchers programmed four gaits specialized to these conditions: walking, crawling, fl apping and paddling.

Baines described the robot’s walking as the “creep” gait, where ART keeps three legs on the ground at all times to remain statically stable. ART’s walking was tested over diverse terrestrial terrains, from predictable lab settings to outdoor environments such as a paved sidewalk or sandy, pebbly turf. The crawling gait, similar to a beaching sea turtle, is designed for the transition zones between land and water, where ART lies on its stomach and pulls itself forward.

Swimming was divided into two separate gaits — fl apping and paddling, modeled after sea and freshwater turtles, respectively. Flapping is more e cient for propulsion when ART is fully submerged, while paddling near the surface yields better acceleration and heightened maneuverability. Changing the angle of the fl ippers, along with the robot’s buoyancy, can make the robot change its depth by diving or surfacing.

Ever since the first prototype was built in 2019, the researchers, each with their own unique skill sets, have been enhancing and optimizing the robot. Waterproofing the system to prevent damage to the motors, electronics and other internal components was one of the di cult challenges they faced early on. Patiballa described the successful control of ART’s buoyancy as another major milestone. The slightest modifi cation in buoyancy could result in ART quickly sinking to the bottom of a pool or fl oating up to the top — fi nding a balance proved to be crucial for submerged swimming.

“Mechanical designers, experts in materials science and biologists who studied actual turtles and their gaits all came together to make this happen,” Luis Ramirez GRD ’27, one of the study’s authors, said.

The researchers used a “costof-transport” metric — the ratio of power input to the productive power output — to evaluate the efficiency of the robot’s locomotion and compare it to a variety of animals and robots. Using this metric, researchers have found that ART can outperform even exclusively terrestrial or exclusively aquatic robots.

Most notable, however, is the design philosophy behind the robot’s first-of-its-kind morphing ability. The researchers’ pioneering use of adaptive morphogenesis lays the groundwork for the next generation of mobile robots, better equipped to face complex natural environments and their interfaces in the real world.

The study was featured on the cover of Nature on Oct. 12, 2022.

Contact ALEX DONG at alex.dong@yale.edu .

U.S. Labor Sec recognizes $10 mil YNHH registered apprentice program

BY YASH ROY STAFF REPORTER

Federal o cials, including U.S. Labor Secretary Marty Walsh, are looking to a Yale New Haven Health apprentice program as the blueprint for a potential $303 million federal grant initiative.

On Friday, Walsh and House Appropriations Chair Rosa DeLauro attended a roundtable at YNHH to hear from students and educators in the first class of YNHH’s Registered Apprentice program. The one-year program enhances the skills of Certifi ed Nursing Assistants like patient care technicians, or PCTs, and patient care associates, or PCAs. Funding for the program comes from a $10 million dollar grant provided to the Connecticut Department of Labor as part of a federal $130 million pilot grant program.

“Our program was the first in the state, and we’re excited about all of its success already,” Program Manager Christine Vanvliet told the News. “Amidst shortages in healthcare staff, skilling up PCTs and PCAs and keeping them in our system will help improve patient care.”

The federal grant program stems from a nationwide nursing shortage, with the Bureau of Labor Statistics estimating that an additional 200,000 nurses are necessary to fill the current gap. Vanvliet told the News that increasing training of PCTs and PCAs who work under nurses can also help fi ll the gap.

MARISA PERYER/STAFF PHOTOGRAPHER

On Friday, YNHH hosted a roundtable with registered apprentices under a federal and state department of labor grant award to the health system.

YNHH won the four-year grant in August of 2021 and launched the program in February.

According to Vanvliet, the program is a 12-month long course with approximately 350 current students. Throughout the course, students attend a monthly fourhour seminar on various skills ranging from communications, team building and the usage of medical technology. As the course is an apprenticeship, the program is “earn and learn:” students are full-time YNHH employees receiving salary.

Students pick up a monthly shift with a registered nurse who mentors and provides guidance and teaching to students. Vanvliet said that mentors have helped students register for courses at Gateway Community College as well as provide career advice.

Vanvliet told the News that YNHH is currently working with schools across the state to recruit students for the program. The program aims to retain graduating students as future workers for YNHH upon graduation.

Students who complete the program will receive a certifi cate from the Federal Labor Department that is transferable and can be used to get a job at another healthcare facility. Students who attended the panel spoke of the benefits they have already seen 10 months into the program.

“This apprenticeship program provided me with techniques to deal with time management and stress reduction,” student Jemisa Volkmay said at the event. “During this time, we use critical thinking to refl ect on our issues and problem solve together using these organizational techniques … So I really appreciate this program.”

Another student, Stanley Baxter, emphasized the importance of representation within the program and in the healthcare industry overall. He spoke of a recent patient who told him that an increase in diversity in the nursing and certified nursing assistant staff of YNHH had made it easier for him to trust the care he received.

The federal grant won by YNHH is supposed to fill nursing gaps but is also specifically tailored to improving representation and providing training to marginalized communities.

According to Vanvliet, YNHH hopes to expand the program to 400 students in the next cycle and educate close to 1400 students during the four year grant period.

“The Yale New Haven Hospital’s program to train patient care technicians is a proven example of how public-private partnerships and strengthening our workforce development system are critical tools for rebuilding our health care workforce,” Walsh wrote to the News.

At the event, DeLauro spoke on the importance of the training program and told attendees that the federal grant that YNHH had received would be codifi ed into the next federal appropriations and increased to a $303 million grant.

Walsh served as the Mayor of Boston before he became Labor Secretary.