Soft robots excel at bending and stretching like living creatures but have struggled with heavy, rigid pumps to move them. Now, researchers have created a tiny, soft pump that uses liquid metal and magnetic forces to power these robots without cumbersome parts.
- Pump is the size of a pea and weighs just 0.2 grams
- Operates under 0.1 volts using magnetohydrodynamics
- Enables flexible, portable soft robots without rigid pumps
What happened
Researchers at the University of Bristol have developed a groundbreaking miniature soft pump designed specifically to address the limitations of traditional pumping systems in soft robotics. The pump, named the Liquid Metal Magnetohydrodynamic Actuator (LIMA), weighs about as much as a dried pumpkin seed and can generate sufficient hydraulic pressure to drive soft robotic actuators. It operates at extremely low voltages and does not rely on bulky compressors or rigid mechanical components.
Unlike conventional pumps that use mechanical parts to push fluids, the LIMA pump leverages electromagnetic forces on a tiny droplet of highly conductive liquid metal inside a soft channel. A magnet beneath the channel and a low electric current cause the liquid metal to oscillate, which displaces fluid and creates a pumping action. This unique approach eliminates the need for rigid moving parts, allowing the pump to be soft, light, and fully integrable with flexible robotic systems.
Why it feels good
This innovation addresses one of the biggest hurdles facing soft robotics: the need for compact, lightweight, and flexible pumping systems. Existing pumps are often heavier and larger than the robots themselves, necessitating tethers to external equipment that limit real-world applications such as wearable devices, medical implants, and search-and-rescue robots. By drastically shrinking the pump size and removing rigid parts, the LIMA pump offers a path to truly portable and adaptable soft robots.
Operating at less than 0.1 volts, this low-power requirement means enhanced safety and easier integration with small onboard power supplies. The use of liquid metal also results in high responsiveness and efficiency. Together, these qualities enable the development of more practical, energy-efficient, and versatile soft robotic technologies that maintain their unique flexibility and biomimetic movements.
What to enjoy or watch next
With this miniature pump technology now demonstrated, the next steps involve integrating it into fully functional soft robotic systems to unlock new applications. Potential uses include ultra-light wearable assistive devices that more naturally complement human movement, flexible medical implants that adapt within the body, and small-scale robots capable of agile movement in complex environments without external connections.
Additionally, this technology may inspire further research into liquid metal and magnetohydrodynamic applications beyond robotics, such as in microfluidic devices or soft actuators for haptic feedback. Keeping an eye on developments from the University of Bristol and the soft robotics field at large promises exciting advances as the tiny pump leads to bigger possibilities.