Exploring Braided Twisted Coiled Actuators

There are billions of people suffering from musculoskeletal injuries worldwide, which involves pain, inflammation, and overall difficulty in motion in one's bones, joints, and muscles. To help with rehabilitation, wearable devices have been developed to support motion. However, to generate enough force, these technologies are often bulky and uncomfortable, which deters their use in clinical practices.

To overcome this, researchers looked into soft actuation systems such as twisted coiled actuators (TCAs) - artificial muscles made from threads.

Since they are made from thread, they are inexpensive, lightweight, and flexible, allowing comfortable and affordable wearable devices that support motion.

Over the 2025 summer, I had the opportunity to work on this project with a graduate student under the supervision of Dr. Ana Luisa Trejos in The Wearable Biomechatronics Laboratory at Western University.

To move larger limbs with efficiency, stronger and more durable TCAs are necessary.

Explore and test different TCA designs (braided) that could support more weight and be used for longer periods of time.

TCAs are made by taking any workable thread, even as simple as nylon fishing lines, and twisting it under tension. The thread eventually starts to coil all along itself. These coils give it the property to contract when heated, and relax when cooled, imitating the functionality of muscles.

To design stronger and more durable TCAs, braided TCAs were explored. These are multi-stranded braid patterns which could therefore increase the contraction forces and improve durability through the multiple strands.

Multiple versions of multi-stranded braid patterns were tested throughout the design process to see how much load each could sustain and its endurance. Design modifications arose from these tests.

As this was early on in the research, further testing would have been done in the future.

2nd Place Winner of the 3-Minute Thesis - Western Summer Research Symposium in 2024-2025.

Braided TCAs hold the potential to be the affordable, comfortable, stronger, and more durable TCAs for wearable devices of musculoskeletal conditions. With such highly effective TCAs readily available, people would no longer need to settle for bulky or ineffective support devices and could improve their quality of life.