New fabric stiffens on demand, suitable for drone limbs, medical devices

A wearable fabric that stiffens on demand has been developed by scientists from NTU Singapore. The new type of fabric is said to be suitable for medical devices and soft robotics, such as drone limbs.

The researchers developed the fabric through a combination of geometric design, 3D printing, and robotic control.

Using this new material, called RoboFabric, the NTU research team has created an elbow support designed to help individuals carry heavier loads.

Wrist support prototype

Researchers also developed a wrist support prototype , which could help stabilize joints for daily activities and benefit patients with Parkinson’s Disease who experience trembling.

“We were inspired by how animals often have multiple functionalities for their limbs through the use of intricate structures , much like the shape-morphing and stiffness-variation in octopuses,” said lead scientist, Nanyang Assistant Professor Wang Yifan from the NTU School of Mechanical and Aerospace Engineering.

“We envision that in the future, patients who need a plaster cast for fractures would have the option of customizing flexible limb support that is fabric-like before stiffening. Unlike conventional rigid and unremovable casts, they would also be easy to put on or remove at the touch of a button.”

Yifan stated that joint supports can also help the elderly in their daily tasks, helping to reduce the muscle strength needed for heavier loads.

Inspired by the scales of pangolins and armadillos

The patent-pending technology is inspired by the scales of pangolins and armadillos, which interlock to form a protective shell. The first step in making the new material is an advanced mathematical algorithm that designs an interlocking system of tiles.

The 3D-printed tiles are then joined together by metal fibers running through tiny channels between them, or by an external soft case, which requires negative air pressure or vacuum to be applied constantly, according to the research .

Contracting and interlocking

When the fibers contract, the tiles interlock and stiffen, increasing the rigidity of RoboFabric over 350 times and providing additional strength and stability.

Published in Science Robotics , the study suggests that RoboFabric could also be applied in robotics.

Prof Wang’s team demonstrates a tiny robot made of thin, wave shaped tiles sealed in an elastic envelope. When a vacuum is applied, the RoboFabric transitions to its designated shape and becomes stiff. Conversely, when the vacuum pressure is removed, it relaxes into a soft state.

This actuation of stiffening and softening allows the small robot to climb like a worm or swim in water, carrying small loads or protecting fragile assets by forming a rigid shell around them. These capabilities are important for exploration and rescue robots that need to move in complex terrains and provide protection on demand, according to the study .