Fabric stiffens on demand, suitable for drone limbs, medical devices

Scientists at NTU Singapore have developed a wearable fabric that stiffens on demand. The new type of fabric is said to be suitable for medical devices and soft robotics, such as drone limbs.

Scientists developed the fabric by combining geometric design, 3D printing and robotic control.

Using this new material, called RoboFabric, the NTU research team has created an elbow rest that aims to help people lift heavier loads.

Wrist Rest Prototype

Scientists have also developed a prototype wrist rest that could help stabilize joints during daily activities and provide relief for Parkinson’s disease patients who experience tremor.

“We were inspired by the fact that animals often have multiple functions in their limbs by using complex structures, similar to the shape-shifting and stiffness-modifying properties of octopuses,” said lead researcher Nanyang Assistant Professor Wang Yifan from NTU’s School of Mechanical and Aerospace Engineering.

“We envision that in the future, patients who need a cast for a fracture will have the option of adjusting a flexible limb support that is like fabric before it stiffens. Unlike conventional rigid and non-removable casts, they will also be easy to put on and take off at the push of a button.”

Yifan said joint stabilizers can also help older people perform daily activities by helping reduce the muscle strength needed to lift heavier weights.

Inspired by the scales of pangolins and armadillos

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

The 3D-printed boards are then joined together using metal fibers running through tiny channels between them or using an external soft casing, which requires the continuous application of negative pressure or vacuum, the study found.

Contracting and blocking

As the fibers contract, the plates interlock and stiffen, increasing RoboFabric’s stiffness by more than 350 times and providing additional strength and stability.

A study published in the journal Science Robotics suggests that RoboFabric could also be used in robotics.

Prof. Wang’s team demonstrates a tiny robot made of thin, wavy plates enclosed in a flexible envelope. When vacuum pressure is applied, RoboFabric assumes its designated shape and becomes rigid. Conversely, when the vacuum pressure is removed, it relaxes into a soft state.

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