UK engineers build tiny pump that could let robots move without bulky motors

Saba Firouznia, research associate at the University of Bristol's Soft Robotics Lab, holds the robotic butterfly powered by a tiny liquid-metal pump. (Image credit: Saba Firouznia) Engineers at the University of Bristol have developed a miniature liquid-metal pump weighing just 0.2 grams that could help soft robots move without bulky pumping systems. With a volume of 0.086 cubic centimetres, the device can drive a robotic butterfly’s flapping wings, change the colours of a bracelet and power a wearable that squeezes a fingertip to simulate touch. The researchers say the pump operates at less than 1 volt, while the university’s announcement puts its operating voltage below 0.1 volts. The findings, published in Nature Communications on May 12, 2026, could open new possibilities for lightweight wearable devices and flexible robots.How does the liquid-metal pump work?The device, known as a liquid-metal magnetohydrodynamic (LIMA) pump, uses electromagnetic forces to move liquid through a small, flexible channel. Its operation rests on magnetohydrodynamics, the physical principle describing how electrically conducting fluids respond to magnetic fields.The pump contains a tiny droplet of ...