Artificial muscles from KAIST are small enough to power robotic butterflies
Researchers at the Korea Advanced Institute of Science and Technology, or KAIST, have developed an ultra-thin actuator for soft robotics. The artificial muscles, recently reported in the journal Science Robotics, were demonstrated with a robotic blooming flower brooch, dancing robotic butterflies, and fluttering tree leaves on a kinetic art piece.
Actuators are the robotic equivalents of muscles, expanding, contracting, or rotating like muscle fibers in response to a stimulus such as electricity. Engineers around the world are striving to develop more dynamic actuators that respond quickly, can bend without breaking, and are very durable. Soft robotic muscles could have a wide variety of applications, from wearable electronics to advanced prosthetics.
Artificial muscles use super-thin materials
The team from KAIST‘s Creative Research Initiative Center for Functionally Antagonistic Nano-Engineering said it developed a very thin, responsive, flexible, and durable artificial muscle. The actuator looks like a skinny strip of paper about an inch long. The researchers used a material called MXene, which is class of compounds that have layers only a few atoms thick.
Their chosen MXene material (T3C2Tx) is made of thin layers of titanium and carbon compounds. It was not flexible by itself; sheets of material would flake off the actuator when bent in a loop. That changed when the MXene was “ionically cross-linked” — connected through an ionic bond — to a synthetic polymer. The combination of materials made the artificial muscles flexible, while still maintaining strength and conductivity, which is critical for movements driven by electricity.
This particular combination performed better than others reported. The actuator responded very quickly to low voltage, and it lasted for more than five hours moving continuously.
KAIST demonstrates wearable art
To prove that the tiny artificial muscles work, the KAIST team incorporated the actuators into wearable art: an origami-inspired brooch mimics how a narcissus flower unfolds its petals when a small amount of electricity is applied. The researchers also designed robotic butterflies that move their wings up and down, and tree sculpture whose leaves can flutter.
“Wearable robotics and kinetic art demonstrate how robotic muscles can have fun and beautiful applications,” said Il-Kwon Oh, lead paper author and professor of mechanical engineering. “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.
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