Engineers at the University of Bristol have developed a miniature liquid-metal pump that could help make soft robots and wearable devices lighter and more adaptable. The device, described in Nature Communications, weighs just 0.2 grams and occupies 0.086 cubic centimetres.
The pump, known as LIMA, uses magnetohydrodynamics to move fluid. When an electric current passes through a liquid-metal droplet in a magnetic field, it generates a force that drives the metal back and forth. This movement displaces surrounding fluid, producing a pumping action.
Unlike conventional systems that rely on bulky compressors or rigid pumps, LIMA operates at very low voltages. Its flexible design could make it useful in applications where size, weight and mobility are important.
The research team demonstrated the technology in several prototypes. One used the pump to control a robotic butterfly’s flapping wings. Another incorporated it into a colour-changing bracelet, while a third demonstrated a wearable fingertip device that squeezes to simulate touch.
The pump can also transmit signals through fluid movement, allowing it to control actions remotely. This could eventually support soft robotic clothing, rehabilitation equipment and wearable interfaces designed to respond to movement or pressure.
The researchers say the device could help address a longstanding challenge in soft robotics: providing sufficient movement without relying on heavy, rigid components. Its compact size and low-voltage operation offer a potential route towards more portable systems.
However, the demonstrations remain at the prototype stage. Further development will be needed before the technology can be incorporated into practical commercial products.
