Robotic Muscles That Flex On Command

Researchers in South Korea have developed an ultrathin, artificial muscle for soft robotics.

AsianScientist (Sep. 24, 2019) – In a study published in Science Robotics, a team of scientists in South Korea has developed robotic muscles that can move when an electrical current is passed through them.

Muscles contract and relax to enable motion in humans. Robots, on the other hand, typically depend on motors and gears to move.

More recently, researchers have been developing actuators to produce motion in robots. The actuator expands, contracts or rotates like muscle fibers using a stimulus such as electricity. Ideally, an actuator should respond quickly to stimuli, bend without breaking and be durable.

In this study, scientists at the Korea Advanced Institute of Science and Technology (KAIST) developed a very thin, responsive, flexible and durable artificial muscle. The actuator, which looks like a skinny strip of paper about an inch long, is made of a material called MXene—a class of compounds that have layers only a few atoms thick.

Their chosen MXene material (Ti3C2Tx) is made of thin layers of titanium and carbon compounds. It was not flexible by itself; sheets of the material would flake off the actuator when it was bent in a loop. That changed when the MXene was ionically cross-linked to a synthetic polymer. The combination of materials made the actuator flexible, while still maintaining strength and conductivity, which is critical for movements driven by electricity.

The researchers demonstrated that their actuator responded very quickly to low voltage, and lasted for more than five hours moving continuously. To prove the tiny robotic muscle works, the team incorporated the actuator into wearable art: an origami-inspired brooch shaped like a narcissus flower that unfolds when a small amount of electricity is applied. They also designed robotic butterflies that move their wings up and down, and made the leaves of a tree sculpture flutter.

“Wearable robotics and kinetic art demonstrate how robotic muscles can have fun and beautiful applications,” said Professor Oh Il-Kwon, lead paper author and professor of mechanical engineering at KAIST. “It also shows the enormous potential for small, artificial muscles for a variety of uses, such as haptic feedback systems and active biomedical devices.”

The team next plans to investigate more practical applications of MXene-based soft actuators and other engineering applications of MXene 2D nanomaterials.

The article can be found at: Umrao et al. (2019) Mxene Artificial Muscles Based on Ionically Cross-linked Ti3C2Tx Electrode for Kinetic Soft Robotics.


Source: RIKEN.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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