Caption: Ashwathi Menon, co-captain of UMBC’s Indian fusion dance team, helps demo some of the technology in the lab. Here, she demonstrates the Katakamukha mudra as a robotic hand mimics her gesture. Parthan Olikkal, a graduate student working on the project, is in the background. Credit: Brad Ziegler/UMBC
Researchers at the University of Maryland, Baltimore County (UMBC) have extracted the building blocks of precise hand gestures used in the classical Indian dance form Bharatanatyam—and found a richer ‘alphabet’ of movement compared to natural grasps. The work could improve how we teach hand movements to robots and offer humans better tools for physical therapy. The work was published online Nov. 24 [2025] in the journal Scientific Reports.
Ramana Vinjamuri, a professor at UMBC and lead researcher on the work, has focused his lab on understanding how the brain controls complex hand movements. More than a decade ago, he and his research partners began searching for and cataloguing the building blocks of hand motions, drawing on a concept called kinematic synergies, in which the brain simultaneously coordinates multiple joint movements to simplify complex motions. The concept can be used to deconstruct a dazzling diversity of movements into a limited number of fundamental units, similar to how the hundreds of thousands of different words in the English language can be broken down into only 26 letters.
Further inspiration struck when Vinjamuri attended a 2023 scientific conference on the brain, hosted by the Indian Institute of Technology Mandi in the serene foothills of the Himalayas. While brainstorming ideas for a session of the conference focused on ways that ancient Indian traditions might be applied to modern problems, Vinjamuri conceived a novel approach to deriving these building blocks—from the wide variety of precise hand gestures, called mudras, used in Indian classical dance to drive the storytelling element of the art form.
“We noticed dancers tend to age super gracefully: They remain flexible and agile because they have been training,” says Vinjamuri. “That was a huge inspiration for us when we started looking for richer alphabets of movement. With dance, we are looking not just at healthy movement, but super healthy. And so the question became, could we find a ‘superhuman’ alphabet from the dance gestures?”
Natural versus structured movements
As part of the newly published research, Vinjamuri and his students started by analyzing a data set of 30 natural hand grasps, used for picking up objects ranging in size from large water bottles to tiny beads. They found six synergies, akin to an alphabet of six letters, that when combined could account for nearly 99 percent of the variations in movements represented in the full data set.
Using the same techniques, the research team also analyzed 30 single-hand mudras. They found six synergies that could account for around 94 percent of the mudras’ variations.
Crucially, the team then tested how well the six natural grasp-derived synergies could combine to construct unrelated hand motions—in this case 15 letters of the American Sign Language alphabet—compared to the mudras-derived synergies. The mudra-derived synergies significantly outperformed the natural hand grasp synergies on that task.
“When we started this type of research more than 15 years ago, we wondered: Can we find a golden alphabet that can be used to reconstruct anything?” says Vinjamuri. “Now I highly doubt that there is such a thing. But the mudras-derived alphabet is definitely better than the natural grasp alphabet because there is more dexterity and more flexibility.”
Ultimately, Vinjamuri envisions coming up with libraries of task-specific alphabets that can be deployed depending on the needs, be it completing everyday household chores such as cooking or folding laundry, or something more complicated and precise, such as playing an instrument.
Robotic helping hands
The team is currently developing techniques to “teach” robotic hands the alphabets of movements and how to combine them to make new hand gestures. The approach marks a departure from standard techniques of teaching robots to mimic hand gestures, and toward a method rooted in our understanding of how the human body and brain work.
The researchers are testing the techniques on a stand-alone robotic hand and a humanoid robot, each of which operates in a different way and requires a unique approach to translating the mathematical representations of synergies into physical movements.
The team has also made great strides developing cost-effective and pragmatic methods of testing and implementing their ideas. They use a simple camera and software system to recognize, record, and analyze movements, an important contribution to ultimately making cost-effective technologies that people could use in their homes, such as a virtual system to coach people through physical therapy sessions, says Vinjamuri.
“Once I learned about synergies, I became so curious to see if we could use them to make a robotic hand respond and perform the same way as a human hand,” says Parthan Olikkal, a longtime member of Vinjamuri’s lab who is currently working toward his Ph.D in computer science. “Adding my own work to the research efforts, and seeing the results has been gratifying.”
Catherine Meyers’s December 15, 2025 article for the UMBC magazine provides a lot more detail along with embedded images,
Fossil records suggest that between four and six million years ago, the hominin ancestors of modern humans first stood up and walked on two legs—thus freeing their hands. Those hands went on to craft humanity’s story arc: cradling babies, carrying food, fashioning and wielding weapons, carving the woodblocks used to print the first paper books, running over the keys of a piano in a Rachmaninoff concerto, and even planting a flag on the surface of the moon.
“Hands are incredibly important to humans,” says Ramana Vinjamuri, an associate professor of computer science and electrical engineering whose work has focused on understanding how the brain controls complex hand movements.
Vinjamuri personally witnessed the debilitating impact of loss of hand movement when his mother suffered a stroke in 2014. “The very hand that taught me how to draw, how to write—I saw that hand irrevocably paralyzed. It was really hard for the family.”
The experience motivated Vinjamuri to work on technologies that could help people regain lost motor functions or serve as robotic replacements for injured body parts. As part of the research, the team began searching for and cataloging the building blocks of hand motions. Further inspiration struck when Vinjamuri attended a scientific conference on the brain, hosted by the Indian Institute of Technology Mandi in the serene foothills of the Himalayas. While brainstorming ideas for a session of the conference focused on ways that ancient Indian traditions might be applied to modern problems, Vinjamuri conceived a novel approach to deriving these building blocks—from the structured hand gestures of Indian classical dance.
A Complex and Versatile Instrument
Take a moment to consider your hands. Including the wrist, each hand has 27 joints. Some of those joints, such as the carpometacarpal joint at the base of the thumb, can move in multiple ways, such as rotating, bending, and moving toward or away from the center of the palm. The full hand encompasses billions of possible unique combinations of movements.
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Dance-Derived Alphabets of Movement
Ashwathi Menon demonstrates mudras, which are copied by an Inspire robotic hand. From top to bottom the mudras are: Ardhachandra, meaning “half moon;” Chandrakala, meaning “crescent moon;” and Tripataka, meaning “three parts of the flag.” The mudras can demonstrate various elements of a story, including weapons, trees, flowers, or concepts such as balance, unity, and beauty.. Courtesy: UMBC
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Here’s a link to and a citation for the paper,
Reconstructing hand gestures with synergies extracted from dance movements by Parthan Olikkal, Chris Dollo, Akshara Ajendla, Ann Sofie Clemmensen & Ramana Vinjamuri. Scientific Reports volume 15, Article number: 41670 (2025) DOI: https://doi.org/10.1038/s41598-025-25563-7 Published: 24 November 2025 Version of record: 24 November 2025
Boron nitride has been exciting members of the scientific community most recently as an alternative to carbon. A Dec. 22, 2015 news item on ScienceDaily,
When mixed with lightweight polymers, tiny carbon tubes reinforce the material, promising lightweight and strong materials for airplanes, spaceships, cars and even sports equipment. While such carbon nanotube-polymer nanocomposites have attracted enormous interest from the materials research community, a group of scientists now has evidence that a different nanotube — made from boron nitride — could offer even more strength per unit of weight.
A Dec. 22, 2015 American Institute of Physics (AIP) news release by Catherine Meyers, which originated the news item, describes why carbon nanotubes have interested scientists and the advantages presented by boron nitride nanotubes (Note: A link has been removed),
Carbon nanotubes are legendary in their strength — at least 30 times stronger than bullet-stopping Kevlar by some estimates. When mixed with lightweight polymers such as plastics and epoxy resins, the tiny tubes reinforce the material, like the rebar in a block of concrete, promising lightweight and strong materials for airplanes, spaceships, cars and even sports equipment.
While such carbon nanotube-polymer nanocomposites have attracted enormous interest from the materials research community, a group of scientists now has evidence that a different nanotube — made from boron nitride — could offer even more strength per unit of weight. …
Boron nitride, like carbon, can form single-atom-thick sheets that are rolled into cylinders to create nanotubes. By themselves boron nitride nanotubes are almost as strong as carbon nanotubes, but their real advantage in a composite material comes from the way they stick strongly to the polymer.
“The weakest link in these nanocomposites is the interface between the polymer and the nanotubes,” said Changhong Ke, an associate professor in the mechanical engineering department at the State University of New York at Binghamton. If you break a composite, the nanotubes left sticking out have clean surfaces, as opposed to having chunks of polymer still stuck to them. The clean break indicates that the connection between the tubes and the polymer fails, Ke noted.
Plucking Nanotubes
Ke and his colleagues devised a novel way to test the strength of the nanotube-polymer link. They sandwiched boron nitride nanotubes between two thin layers of polymer, with some of the nanotubes left sticking out. They selected only the tubes that were sticking straight out of the polymer, and then welded the nanotube to the tip of a tiny cantilever beam. The team applied a force on the beam and tugged increasingly harder on the nanotube until it was ripped free of the polymer.
The researchers found that the force required to pluck out a nanotube at first increased with the nanotube length, but then plateaued. The behavior is a sign that the connection between the nanotube and the polymer is failing through a crack that forms and then spreads, Ke said.
The researchers tested two forms of polymer: epoxy and poly(methyl methacrylate), or PMMA, which is the same material used for Plexiglas. They found that the epoxy-boron nitride nanotube interface was stronger than the PMMA-nanotube interface. They also found that both polymer-boron nitride nanotube binding strengths were higher than those reported for carbon nanotubes — 35 percent higher for the PMMA interface and approximately 20 percent higher for the epoxy interface.
The Advantages of Boron Nitride Nanotubes
Boron nitride nanotubes likely bind more strongly to polymers because of the way the electrons are arranged in the molecules, Ke explained. In carbon nanotubes, all carbon atoms have equal charges in their nucleus, so the atoms share electrons equally. In boron nitride, the nitrogen atom has more protons than the boron atom, so it hogs more of the electrons in the bond. The unequal charge distribution leads to a stronger attraction between the boron nitride and the polymer molecules, as verified by molecular dynamics simulations performed by Ke’s colleagues in Dr. Xianqiao Wang’s group at the University of Georgia.
Boron nitride nanotubes also have additional advantages over carbon nanotubes, Ke said. They are more stable at high temperatures and they can better absorb neutron radiation, both advantageous properties in the extreme environment of outer space. In addition, boron nitride nanotubes are piezoelectric, which means they can generate an electric charge when stretched. This property means the material offers energy harvesting as well as sensing and actuation capabilities.
The news release does note that boron nitride nanotubes have a drawback ,
The main drawback to boron nitride nanotubes is the cost. Currently they sell for about $1,000 per gram, compared to the $10-20 per gram for carbon nanotubes, Ke said. He is optimistic that the price will come down, though, noting that carbon nanotubes were similarly expensive when they were first developed.
“I think boron nitride nanotubes are the future for making polymer composites for the aerospace industry,” he said.
