Core Technology
Fabric Muscle
We replaced the robot's actuator with fabric.
Fabric Muscle is an artificial muscle actuator made by processing shape memory alloy (SMA) — thinner than human hair — into coil-shaped threads, then weaving them like fabric.
When electric current flows, the SMA contracts like a muscle as it tries to return to its original shape — 10g of Fabric Muscle lifts 10kg. The maximum load ratio is 1,500 times its own weight.
This implements the working principle of the sarcomere — the basic contractile unit of muscle — in textile form. The name SARTEXO itself originates from this technology.
Because it is fabric, it can be cut and sewn along designed patterns — so it can become a suit worn over workwear, or a design built into it. The product built this way is SARTEXO's textile wearable robot, Bionic Suit.
How It Works — 3 Steps
Shape Memory Alloy Wire
SMA Wire
Uses thin shape memory alloy wire, 25–40 μm in diameter.
Coiling & Weaving
Coil & Weave
The wire is processed into coil-spring thread, then woven like fabric into a textile actuator spanning a wide surface.
Contract & Relax
Works Like a Muscle
Applying current makes it contract; it then cools and recovers before the next motion.
Mass Production
Opening the Era of Mass Production with Auto-Weaving
In 2025, we developed an automated weaving machine capable of continuous mass production of Fabric Muscle.
Previously, metal core threads limited elongation. We solved this by replacing them with natural fiber core threads.
This achieved manufacturing economics viable for mass production, laying the foundation for dramatically reducing wearable robot prices.
Continuous
Auto-weaving method
Natural Fiber
Core thread material
Mass Production
Manufacturing economics
Fabric Muscle Performance
Fabric Muscle performance
Properties confirmed at the material level, shown with demo videos in the order contraction → actuation speed.
40% contraction · 10 kg load
Fabric Muscle contracts over 40% of its length while lifting 10 kg — approaching the contraction ratio of human muscle.
2 Hz high-speed actuation · 10 kg load
In the demonstration, a 10 g actuator drives a 10 kg load twice per second. The load ratio in this demo is 1,000× the actuator's weight; the maximum load ratio is 1,500×.
25~40 µm
SMA wire diameter
A quarter to a half of a human hair
Up to 1,500×
Load relative to actuator weight
Maximum load ratio to its own weight (test maximum)
10~15 kg
Lift per 10 g
With just 10 g of Fabric Muscle
40%
Contraction ratio
Of its own length — close to human muscle
2 Hz
Actuation speed
Driving a 10 kg load twice per second
In the demo videos a 10 g actuator lifts 10 kg (1,000× its weight). The maximum load ratio is 1,500×.
Cut and sewn along designed patterns
It is cut and sewn into the form needed for garment integration, on standard garment equipment and without a separate robot assembly line. Where and how to process it is covered in our technical documentation.
From Fabric Muscle to Bionic Suit
From Fabric Muscle to the suit
Cut and sewn along designed patterns into garment form, this Fabric Muscle becomes SARTEXO's clothing-type strength-assist suit, the Bionic Suit. One core material extends to four products by assisted body part and to standalone actuators.
Fabric Muscle
The core Fabric Muscle technology
Product Line
Bionic Suit
Waist · Upper · Lower · Full — a lineup by assisted region
- Bionic Suit Waist
- Bionic Suit Upper
- Bionic Suit Lower
- Bionic Suit Full
Component Supply
Fabric Muscle Actuators
Standalone actuators for research institutes and companies
- Actuator modules for research
- Evaluation samples for industry
We support both standard sizing and custom design, and our automated weaving equipment enables mass production.
Bionic Suit Technology
Bionic Suit technology
What sets Fabric Muscle apart once it becomes a product, and how it has been validated.
Form Factor
Evolution of Form Factor
Generations are defined by where the actuator sits.
1st generation · Machine
Rigid Exoskeleton
You fit your body to the machine frame
Actuator location — On the frame
2nd generation · Gear
Soft Exosuit
You strap the gear tight to your body
Actuator location — A separate part on the body
3rd generation · Clothing
Textile Wearable Robot
You wear it — the clothing is the robot
Actuator location — The fabric itself
The fabric itself is the actuator. A different form factor.
How It Works
Where does the assisting force come from?
When the structure that makes the force differs, so do the results. Here are the principle of each approach and the results that follow from its structure — side by side.
Approach using elastic elements such as springs and bands
Principle
Stretches to store energy when you bend, and returns it when you straighten
What the structure leads to
- Assistance begins only after the person moves first
- It returns what it stores, so it works at a preset strength
Power Not required
Motor and cable approach
Principle
A motor pulls cables to assist the joints
What the structure leads to
- The size and timing of force can be controlled
- Needs motors, gearboxes and a structure to hold them — its form varies by product
- Motors and gearboxes produce drive noise — the level varies by product
Power Required (battery)
Fabric Muscle approach — SARTEXO
Principle
When current flows, the fabric itself contracts
What the structure leads to
- The size and timing of force can be controlled
- No motors or gearboxes, so no drive noise
- No frame or hinge — the structure does not constrain body movement
- It can be cut and sewn along designed patterns, so it can be integrated into clothing
Power Required (swappable battery)
What each structure leads to
| Category | Springs & elastic bandsGear | Motor & cableMachine · Gear | Fabric Muscle (SARTEXO)Clothing (Textile) |
|---|---|---|---|
| Generation | 2nd gen | 1st–2nd gen | 3rd gen |
| How force is made | Returns restoring force stored by bending or stretching | A motor pulls a cable to transmit force | Current makes the fabric itself contract |
| When assist starts | After the person moves first | When the controller drives the motor | When the controller applies current |
| Force adjustment | Preset by elastic stiffness (adjustment during use varies by product) | Adjusted by the controller | Adjusted by current control |
| Drive noise | None — no powered drive | Motor and gearbox sound (level varies by product) | None — no motors or gearboxes |
| Structure | Varies by product | Needs a structure to hold motors and gearboxes (frame or soft form varies by product) | Contracts within the fabric, with no frame or hinge |
| Garment integration | Depends on product structure | Design must account for motor and gearbox placement | Cut and sewn per designed pattern, integrated directly into clothing |
| Power | Not required | Required (battery) | Required (swappable battery) |
Fabric Muscle Advantage
A different form factor changes what you get
These follow from the fabric itself being the actuator.
NEW FORM FACTOR — 3RD GENERATION TEXTILE WEARABLE ROBOT
SARTEXO — Fabric Muscle
The fabric itself is the actuator. Electrical energy contracts Fabric Muscle to assist movement, without motors, cables or a metal frame.
- Combines a flexible clothing-type structure, active actuation and simultaneous 3-joint assist
- The fabric itself is the actuator, so no separate power transmission is needed
1.3 kg
Waist-assist suit weight
Including battery and controller (Waist)
840 g
Shoulder-only assist suit weight
Shoulder–elbow configuration specified separately
Under 2 kg
World's first 3-joint clothing-type suit
Waist, shoulder, elbow (Full) · incl. battery & controller · Korea Institute of Machinery & Materials press release, Oct 2025
40%
40%+ less lower-back muscle activity
Lower-back assist evaluation · healthy adult workers · repetitive lifting — a different figure from the 40% material contraction. Tested model, load and measurement method provided in consultation
57%
Shoulder range-of-motion gain
Shoulder-assist suit · patients with Duchenne muscular dystrophy · shoulder range with the upper-body assist — IEEE TNSRE (2025)
The three groups differ in what was tested and under which conditions. Actuator-level figures (①) are not suit performance, and work-assist (②) and patient-clinical (③) results are not interchangeable.
Evidence
Technology backed by patents and papers
Granted patents on the material, mass-production process and actuator design, and peer-reviewed papers on Fabric Muscle and the suits built with it.
Key patents
Fabric Woven with SMA Springs and Textile-Type Soft Actuator
KR 10-2621558 (2024)
Continuous Manufacturing Apparatus and Method for SMA Springs
KR 10-1967214 (2019)
Modular Joint-Specific Assistive Wearable Robot Using Fabric Actuators
KR 10-2388069 (2022)
Soft Actuator with Cooling System and Wearable Robot
US 12,491,626 (2025)
Driving Apparatus and Method for Artificial Muscle Modules
US 10,792,806 (2020)
Selected papers
Soft Exosuit Based on Fabric Muscle to Assist Shoulder Joint Movements in Patients with Neuromuscular Diseases
IEEE TNSRE (2025)
Wrist Assisting Soft Wearable Robot With Stretchable Coolant Vessel Integrated SMA Muscle
IEEE/ASME Transactions on Mechatronics (2022)
Soft fabric muscle based on thin diameter SMA springs
Smart Materials and Structures (2022)
Fabric muscle with a cooling acceleration structure for upper limb assistance soft exosuits
Scientific Reports (2022)
Soft Exosuit Based on Fabric Muscle for Upper Limb Assistance
IEEE/ASME Transactions on Mechatronics (2022)
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