Researchers have created a fabric that acts as a powerful mechanical actuator while remaining soft, stretchable and suitable for clothing. By embedding shape memory alloy fibres in a precisely aligned crossing pattern, the textile contracts strongly when electrically heated, avoiding internal force losses seen in earlier designs. The result is a lightweight fabric capable of delivering controlled movement and compression without rigid hardware.
- The textile integrates thin nickel–titanium alloy fibres that shorten and stiffen when heated, generating mechanical force directly within a flexible fabric structure.
- A fabric sample weighing 4.5 grams lifted a one-kilogram load while remaining stretchable to 160 per cent of its original length.
- Prototype demonstrations showed the fabric assisting elbow movement and providing controlled on-body compression for medical or athletic applications.
- The work was published in Science Advances by researchers from EPFL’s Soft Transducers Laboratory, detailing the X-crossing geometry and its performance model.
- The paper ‘Mechanics-informed fabric actuators with aligned fibre crossings’ was authored by Huapeng Zhang and Herbert Shea of the Soft Transducers Lab, École Polytechnique Fédérale de Lausanne, Switzerland, and published in Science Advances.
WHAT WAS STUDIED: The research set out to overcome long-standing limitations in wearable robotic textiles, where rigid components or inefficient fibre layouts restrict comfort and usable force. The team developed a fabric actuator using shape memory alloy fibres arranged in a repeating X-crossing geometry, designed to align force generation in a single direction. The study was published in Science Advances and led by researchers working in soft transducers and wearable actuation systems.
- The actuator relies on thin nickel–titanium alloy fibres that shorten and stiffen when heated using an electrical current.
- Earlier textile approaches often lost efficiency because fibres pulled against each other during contraction, reducing usable force.
- The X-crossing layout ensures each fibre intersection contributes constructively to movement rather than cancelling neighbouring forces.
MEASURED PERFORMANCE: Tests reported in the study showed that aligning shape memory alloy fibres through the X-crossing geometry delivered unusually high force without sacrificing flexibility. When electrically activated, the fibres contracted by about 50 per cent, allowing the fabric to lift loads far heavier than its own weight. The architecture also preserved stretchability, enabling the textile to be extended significantly without damaging the actuator structure.
- A fabric sample weighing 4.5 grams lifted a one-kilogram load under controlled laboratory conditions.
- The textile could be stretched to roughly 160 per cent of its original length, supporting ease of wearing and removal.
- Modelling captured how fibre stiffness changes with temperature and stress, improving predictions of force and contraction under different loads.
IN PRACTICAL TERMS: To demonstrate practical use beyond laboratory testing, the researchers integrated the textile actuators into simple wearable prototypes. Mounted on an arm form, the fabric provided assisted elbow bending through a controlled range of motion. In a separate demonstration, the same architecture was used to apply on-body compression, a requirement for medical and athletic garments.
- The actuator lifted a one-kilogram load through a thirty-degree elbow movement in a smooth, controlled motion.
- Compression tests showed the fabric could maintain applied pressure at zero energy cost once activated, a key advantage for medical and assistive wearables.
- The design points to garments that provide discreet mechanical support while remaining flexible and unobtrusive.
WHAT THEY SAID
We realised that the orientation of fibre crossings plays a critical role in how forces add up inside a textile actuator. By aligning the crossings, we ensure that the forces generated at each intersection contribute constructively, rather than working against each other.
— Huapeng Zhang
PhD Student
Soft Transducers Laboratory, EPFL
