Soft robotics is experiencing a renaissance thanks to a concept as old as science itself: the use of water vapor. A team from the University of Coimbra has taken a step forward by presenting a phase transition actuator that transforms the controlled boiling of water into precise and powerful mechanical motion.
Innovation in wireless soft robots
Until now, soft robots soft robots relied on bulky pneumatic systems or exotic materials. The Portuguese proposal introduces a soft electrical system powered by just 24 V that uses integrated heating elements to generate steam. This process drives actuators made of elastomers and water, allowing forces in excess of 50 N and pressurization rates of 100 kPa/s to be generated .
The researchers took advantage of the vaporization enthalpy of water, traditionally seen as an obstacle, to achieve stable actuation cycles exceeding 1,000 cycles, while solving vibration problems using nonlinear control algorithms. Their findings were recently published in the prestigious journal Nature Communications.
Modular and versatile applications
The team developed modular actuators separated into three key components: the heating coil, the fluid chamber and the flexible outer structure. This design facilitates diverse applications, from McKibben-type linear motions to Pneu-Net geometry-inspired bending.
Among the prototypes presented were a biomimetic robotic hand capable of manipulating delicate objects, an adaptable gripper for picking fruit of various shapes and weights, and Bixo, a quadrupedal quadruped robot that climbs pipes and logs with a grip-and-release cycle managed by localized heating and cooling.
Prospects for robots without pumps and high-voltage systems
The future of this technology points towards miniaturization of actuators, improved heat dissipation and increased operating pressure. This approach opens the door to a new generation of flexible robots. flexible, safe and affordableThis approach opens the door to a new generation of flexible, safe and affordable robots that will be able to operate in natural environments without the need for pneumatic pumps or the risks associated with high-voltage systems.
According to the researchers, the key lies in efficiently harnessing the liquid-gas transition, demonstrating that even with a liquid as common as water, it is possible to push robotics towards more sustainable and scalable applications.
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Source and photo: Tech Xplore
