By Heather Hamilton, contributing writer
Robotics makers have faced the persistent challenge of making machines that function in the same way that humans do — earlier this month, Boston Dynamics revealed a robot that could backflip. But even as the robotics field has grown, emulating human tissues and movement continues to present a challenge. Flexibility and dexterity often mean a decrease in overall strength, which can interfere with use.
Researchers from the Wyss Institute at Harvard University and MIT’s Computer Science and Artificial Intelligence Laboratory may have a solution, inspired by origami that adds both strength and flexibility.
According to a study in Proceedings of the National Academy of Sciences,the artificial muscles can lift up to 1,000 times their own weight using air or water pressure. Daniela Rus, senior author at Professor of Electrical Engineering and Computer Science at MIT says that she was shocked at how strong the muscles actually were. “We expected they’d have a higher maximum functional weight than ordinary soft robots, but we didn’t expect a thousand-fold increase,” she said. “It’s like giving these robots superpowers.”
After creating muscles made from a range of materials (metal springs, plastic, packing foam, etc.), the researchers experimented with skeleton shapes to find muscles that, by sucking the air out, were able to contract to 10% of their size, lift a flower off the ground, and twist in a coil.
The muscles generate six times more force per unit than mammalian muscles, are lightweight, can (at 2.6 grams) lift an object that weighs 3 kilograms, are highly scalable, and can be made in 10 minutes from materials amounting to less than $1.
The muscles are powered by a vacuum, which makes them very safe, an important factor given their frequent proximity to humans. They’re unlikely to rupture, fail, or become damaged, which means that they can go on the human body. These muscles can also be made from water-soluble polymer PVA, which means that they pose relatively little risk of environmental impact and can even be digested.
Rob Wood, an author of the study and Founding Core Faculty member of the Wyss Institute, and Charles River, Professor of Engineering and Applied Sciences at Harvard, believes that artificial muscle-like actuators are one of the most important challenges in the entire field of engineering. “Now that we have created actuators with properties similar to natural muscle, we can imagine building almost any robot for almost any task,” says Wood.
The artificial muscles contain an inner skeleton made of material such as a metal coil or a carefully folded sheet of plastic surrounded by either air or fluid and sealed within a bag, much like skin. Then a vacuum in the bag stimulates muscle contraction by causing the skin to collapse onto the skeleton, which forms tension that initiates motion.
The shape and composition of the skeleton is solely responsible for directing muscle movement, which makes the muscles especially unique. Shuguang Li, Postdoctoral Fellow at the Wyss Institute and MIT CSAIL, says that the muscles are largely programmable because humans get to design how the skeleton folds. “You essentially get that motion for free, without the need for a control system,” he continues. Because of this, the muscles are small and simple, allowing for their use in smaller systems that can’t hold larger machinery.
Rus believes that robot creators have to ask if the intelligence lies in the body or the brain — in this case, it’s the body, which she says has the potential to simplify algorithms necessary for the robot to achieve its goal.
So what’s next? “The possibilities really are limitless,” says Rus. “But the very next thing I would like to build with these muscles is an elephant robot with a trunk that can manipulate the world in ways that are flexible and powerful as you see in real elephants.”
Source: Wyss Institute, Proceedings of the National Academy of Sciences
Image Source: Pixabay
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