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Soft robots are often praised for their flexibility, safety, and ability to interact with delicate environments. But many of these systems still depend on a hidden weakness: bulky pumps and compressors. Whether used in wearable devices, robotic grippers, or soft actuators, conventional pneumatic hardware adds weight, limits portability, and makes fully autonomous soft robots difficult to build.
Researchers have now developed a miniature liquid-metal pump designed to replace much of that supporting hardware. The device, known as the LIMA (Liquid-Metal Magnetohydrodynamic) pump, weighs only 0.2 grams and operates at less than 0.1 volts, making it small enough to integrate directly into soft robotic systems.
Unlike traditional pumps that rely on moving mechanical parts, the LIMA pump uses liquid metal droplets suspended inside a magnetic field. When an electric current passes through the conductive liquid metal, it generates a Lorentz force, which is a physical interaction between electricity and magnetism, that pushes the droplets through the system. According to Interesting Engineering, this movement creates pressure and fluid flow without requiring motors, pistons, or rigid mechanical components.
The liquid metal’s high electrical conductivity and ability to deform easily allow the pump to generate useful hydraulic pressure while consuming very little power. Researchers demonstrated the concept using several prototype systems, including robotic butterfly wings, a wearable bracelet capable of changing appearance, and a haptic feedback device that recreates touch sensations by inflating a small pouch against the user’s fingertip.
One of the more unusual aspects of the technology is that it can do more than simply move fluid; the same liquid-metal network can potentially transfer hydraulic energy, chemical signals, and information through soft structures. This could allow future robotic systems to combine sensing, communication, and actuation within a single integrated architecture.
From a defense and security perspective, lightweight pumping systems could support wearable technologies, soft robotic platforms, compact medical devices, and autonomous systems where size, weight, and power consumption are critical constraints. Reducing reliance on rigid mechanical hardware may also enable robotic systems that are more adaptable and easier to deploy in confined or unpredictable environments.
Researchers are already exploring additional applications ranging from smart bandages and robotic clothing to ingestible robots, suggesting that miniature fluidic systems may become a key building block in future soft-machine design.
The research was published here.
