In Japan, engineers are trying to make robots imitate a typically human expression: the smile.
They created a face mask from human skin cells and attached it to robots with an innovative technique that hides the binding and is flexible enough to transform into a grimace or cheesy smile.
The effect is halfway between the terrifying Hannibal Lecter mask and the Gumby claymation figure.
But scientists say the prototypes pave the way for more sophisticated robots, with an outer layer that is elastic and strong enough to protect the machine while making it more humane.
According to a study published June 25 in the journal Cell Reports Physical Science, the “skin equivalent,” as researchers call it, made from live skin cells in the laboratory, can scar, burn and even self-heal. .
“Human-like faces and expressions improve communication and empathy in human-robot interactions, making robots more effective in healthcare, service and companionship roles,” he said in an email. mail Shoji Takeuchi, professor at the University of Tokyo and principal investigator of the study.
The research comes at a time when robots are becoming more ubiquitous in factories.
According to the International Federation of Robotics, as of 2022 there were 3.9 million industrial robots working on automotive and electronics assembly lines and other work environments.
A subset of the total robot fleet includes so-called humanoids, machines designed with two arms and two legs that allow them to work in environments built for human workers, such as factories, but also in the hospitality, healthcare and education sectors.
Carsten Heer, a spokesman for the federation, said humanoids represented “an exciting area of development,” but that mass adoption would be complex and could be limited by costs.
However, in October 2023, the Chinese government announced a goal to mass-produce humanoids by 2025, which was predicted to significantly increase its industrial productivity.
For decades, robotics engineers have experimented with materials, hoping to find something that could protect a robot's complex machinery yet be soft and lightweight enough for a wide range of uses.
If a robot's surface gets dented or scratched, it can cause the machine to malfunction, making self-repairing a “critical feature” for humanoid robots, the researchers said in the paper.
The new method of attachment to the skin advances the nascent field of “biohybrid” robotics, which integrates mechanical engineering with genetic and tissue engineering, said Kevin Lynch, director of the Center for Robotics and Biosystems at Northwestern University.
“This study is an innovative contribution to the problem of anchoring artificial skin to the underlying material,” Professor Lynch said, adding that “living skin could help us achieve the Holy Grail of self-healing skin in biohybrid robots.”
He added that the study does not address how the robots' skin would be able to heal itself without external support.
For these robots, the materials challenge extends to lifelikeness: finding ways to imbue the machine with features that make it look and behave more like a human, such as the ability to smile.
Scientists, including Professor Takeuchi and his colleagues at the University of Tokyo, have been working with laboratory-grown human skin for years.
In 2022, the research team developed a robotic finger covered in living skin, which allows the machine finger to bend like a human finger, giving it the tactility needed to potentially perform more precise tasks.
Professor Takeuchi’s team had tried anchoring the skin with mini-hooks, but these caused tears as the robot moved. So the team decided to mimic ligaments, the small cords of loose tissue that connect bones.
Team members drilled small V-shaped holes into the robot and applied a collagen-containing gel, which plugged the holes and attached the artificial skin to the robot.
“This approach integrates traditional rigid robots with soft, biological skins, making them more 'human-like,'” said Yifan Wang, an associate professor in the faculty of mechanical and aerospace engineering at Nanyang Technological University in Singapore, who studies “robots soft” that imitate biological creatures.
Skin bonding also gives a biohybrid robot the potential to create sensations, taking science one step closer to sci-fi fantasy.
“This could create opportunities for the robot to safely sense and interact with humans,” said Professor Wang.
The faces of the artificially skinned robots in Professor Takeuchi's lab lack the ability to sense touch, temperature changes, or other external stimuli.
Professor Takeuchi said this will be his next research focus.
“Our goal is to create skin that closely mimics the functionality of real skin by gradually building essential components such as blood vessels, nerves, sweat glands, sebaceous glands and hair follicles,” he said.
Instead of neural systems transmitting sensations into a human body, a robot’s electronics would have to feed a sensor signal, a development that Professor Wang says would require much more time and research.