Researchers at EPFL have developed FiberMotor, a tiny thread-like electric motor measuring one to three millimeters in diameter that generates linear motion for textiles and soft robots. Announced by the institution’s Soft Transducers Laboratory, the technology uses concentric hollow fibers and electrostatic forces to move silently without bulky transmissions.
Wearable robotics and smart clothing have long relied on rigid motors, bulky transmissions, and traditional gears to create physical movement. A team at EPFL’s Soft Transducers Laboratory has introduced an alternative that integrates directly into fabric.
How EPFL Built the Sliding FiberMotor
The device measures between one and three millimeters in diameter. When voltage is applied, electrostatic forces pull the two fibers into alignment, causing the inner fiber to slide repeatedly inside the outer fiber in a telescoping movement.
Researchers at EPFL’s Soft Transducers Laboratory have developed FiberMotor, a threadlike motor just 1-3 millimeters in diameter that converts electrical energy directly into linear motion without gears or transmissions. Two concentric hollow fibers are wrapped with hair-thin… pic.twitter.com/ZsdHm0mMwC
— https://x.com/IntEngineering/status/2108882755899535468
Our FiberMotor is the first fiber-format, sliding motor. It produces enough force to actuate devices for soft robotic applications, while remaining silent, flexible, and bidirectional.
Herbert Shea, head of the Soft Transducers Lab at EPFL
This configuration makes the motor backdrivable. The researchers report that the range of motion depends primarily on the length of the fibers rather than material deformation. Laboratory tests showed that a single motor can support a stationary load of roughly 75 grams.
Laboratory Tests and Prototype Garments
In tests reported by EPFL, bundling four motors together allowed the system to lift a chocolate bar weighing 46 grams and flex a tendon-driven robotic finger. The team also stitched the technology into a prototype garment fitted around a mannequin’s knee. Because the motors are thin and lightweight, designers can distribute them across fabric rather than concentrating weight in a single rigid assembly.
Sylvain Schaller is pursuing commercialization of the technology through his startup, Elecsyor. Meanwhile, EPFL researchers are working to improve durability, optimize materials, and develop thinner electrodes made largely from insulating materials.
Technical Hurdles and Unresolved Questions
Despite successful laboratory demonstrations, integrating the motors into everyday clothing presents several engineering challenges. Experiments described in the research papers relied on a high voltage supply connected to mains power, with speed tests running at two to three kilovolts. Building a practical garment requires accounting for a battery, wiring, insulation, and voltage conversion.
Physical wear also introduces limits. The researchers reported successful operation at a bend radius of 60 millimeters, while tighter curves stalled the tested configuration. Twisting and stretching were not characterized in the available literature. Lifetimes typically exceeded 1,000 cycles, with some samples running continuously for 24 hours before electrical insulation breakdown caused failure.
None of the available sources specify how long the motors would last when exposed to everyday wear, sweat, rubbing, and washing, nor do they clarify the exact battery requirements for a finished garment.