Wearable robots have always wrestled with the same tradeoff: more power means more bulk. Motors and pneumatic actuators can move weight, but they add plenty of it, too. Engineers at the Korea Institute of Machinery and Materials (KIMM) are changing that by weaving artificial muscles directly into fabric — and doing it automatically, at scale.
Their new system spins shape-memory alloy (SMA) coil yarns thinner than a strand of hair into flexible, textile-like actuators. The result is a material light enough to wear but strong enough to do real work. A swatch that weighs just ten grams can lift more than ten kilograms.
Until now, that kind of precision weaving wasn’t possible. Metal cores inside earlier SMA yarns made them too stiff for automated looms. The KIMM team replaced the metal with natural fiber, redesigned the coil geometry, and fine-tuned the weaving process to run continuously. The payoff: a repeatable way to mass-produce what they call “fabric muscle”,” a critical step toward wearable robots that look and feel like clothes rather than machines.
Redefining Motion Assistance
The research group, led by Dr. Cheol Hoon Park at KIMM’s Advanced Robotics Research Center, built a working prototype to show what their new material can do. The clothing-type robot weighs less than two kilograms and can assist the shoulder, elbow, and waist simultaneously. In lab tests, it reduced muscle effort by more than 40% during repetitive physical tasks — a big deal for workers in logistics, assembly, or healthcare environments where strain and fatigue are constant.
Traditional wearable robots rely on motors or pneumatics that are heavy, noisy, and power-hungry. They’re usually limited to one joint at a time. The KIMM fabric muscles move silently, flex naturally, and follow the body’s contours, enabling motion assistance that feels closer to human movement than mechanical actuation.
A Lighter Touch for Rehabilitation
Beyond industrial applications, the team also designed an 840-gram shoulder-assist version intended for patients with muscular weakness. In clinical trials at Seoul National University Hospital, people with Duchenne muscular dystrophy and similar conditions showed a 57% improvement in shoulder mobility. The soft, conforming design lets patients wear the assistive fabric under normal clothing — a major step toward real-world usability.
Scaling Toward Commercialization
Automating the weaving process solves one of the last big barriers to commercialization: consistency. Hand-made fabric actuators vary from batch to batch, making it nearly impossible to guarantee uniform performance or longevity. KIMM’s system can now produce continuous rolls of SMA-based fabric muscle with the same tension, spacing, and elasticity every time.
“This development bridges the gap between prototype and product,” said Dr. Park. “By automating the weaving of SMA fabric muscle, we can finally scale wearable robotics that are soft, silent, and efficient enough for everyday use.”
The work, which earned KIMM’s Best Research Award 2024, was supported by Korea’s Ministry of Trade, Industry and Resources and the Lee Kun-hee Child Cancer and Rare Disease Project at Seoul National University Hospital. The results were published in IEEE Transactions on Neural Systems and Rehabilitation Engineering.
Original Story: KIMM Press Release | Korea Institute of Machinery & Materials
