Korean artificial muscle lifts 4,000 times its own weight

Researchers in South Korea have developed an artificial muscle that can lift approximately 4,000 times its own weight, marking a significant breakthrough in robotics engineering. This innovation could revolutionize humanoid robot design by solving the longstanding trade-off between flexibility and strength that has limited artificial muscle technology.

The big picture: Traditional artificial muscles face a fundamental limitation where they’re either highly stretchable but weak, or strong but inflexible, restricting their practical applications in robotics.

How it works: The artificial muscle uses a “high-performance magnetic composite actuator” design that combines two distinct mechanisms for unprecedented versatility.

• The system integrates permanently bonded chemical networks with reversible, physically interacting networks to provide long-term durability.
• Magnetic microparticles are dispersed throughout the polymer matrix and can be controlled via a colorless liquid coating.
• The muscle automatically stiffens when bearing heavy loads and softens when it needs to contract.

In plain English: Think of it like a smart material that can switch between being as rigid as a steel cable when lifting heavy objects and as flexible as a rubber band when it needs to bend and move—all controlled by magnetic particles embedded within it.

Key performance metrics: The synthetic muscle dramatically outperforms both traditional artificial muscles and human tissue in several critical areas.

• In its stiffened state, the muscle weighs just 0.04 ounce (1.13 grams) but can support up to 11 pounds (5 kilograms).
• It achieves 86.4% strain compared to human muscle’s 40% contraction capability.
• The work density reaches 1,150 kilojoules per meter cubed—30 times higher than human tissue.

What the researchers are saying: The breakthrough addresses core limitations that have prevented widespread adoption of artificial muscle technology.

• “This research overcomes the fundamental limitation where traditional artificial muscles are either highly stretchable but weak or strong but stiff,” said lead study author Hoon Eui Jeong, a professor of mechanical engineering at the Ulsan National Institute of Science and Technology.
• “Our composite material can do both, opening the door to more versatile soft robots, wearable devices, and intuitive human-machine interfaces.”

Why this matters: Soft artificial muscles are considered transformative because they’re lightweight, mechanically compliant, and capable of multidirectional movement—essential qualities for next-generation humanoid robots and wearable technology applications.