We often highlight wearable sensors, remote patient monitoring (RPM), artificial intelligence-driven applications in medicine, hearables, and medical grade multi-sensors. Assistive wearables also beep loudly on our interest sonar, however, usually in the form of prosthetics or robotics.

A research group at the Department of Engineering Mathematics of the University of Bristol recently published a study in Science Robotics. The study outlines their work creating artificial muscles for soft robotic wearables. When incorporated with assistive clothing, the wearables can help people with disabilities and age-related muscle degeneration.

The Bristol breakthrough development is a soft, low-cost electro-pneumatic pump to power the soft assistive muscles. The engineers constructed the soft robotics using flexible materials that can stretch and twist. Pneumatic artificial muscles traditionally get their contraction power from relatively large, noisy, expensive pumps powered by electricity. The Bristol research team created a credit card-sized soft electro-pneumatic pump that can pump fluids and power pneumatic bubble artificial muscles (BAMs).

The pump consists of insulated electrodes mounted on a backing material. The team encased the electro-pneumatic pump in a pouch. A tiny drop of a dielectric liquid inside the pouch can amplify an electrostatic force that is created between the two layers. According to the Bristol engineers, this process uses the concept of dielectrophoretic liquid zipping (DLZ). Voltage applied to the pump causes the electrodes to zip the pouch shut. As the electrodes close tighter, they push air that powers the soft robotic muscle. By varying the voltage the muscle will contact with different speed and force.

Next steps for the Bristol team include making the electro-pneumatic pumps smaller and more efficient. The group also seeks working partners to develop manufacturing and production to incorporate the soft robotic muscles in comfortable power-assisting garments.