Some scientists have created a special type of robot capable of switching between soft and hard states, inspired by the sea cucumber.
Researchers have once again transformed science fiction into simple science by creating a shape-shifting robot, similar to the robots in “The Terminator,” that can melt and solidify on command without sacrificing its strength.
This new type of robot was developed by combining the best aspects of current robotic technology.
Chengfeng Pan, the lead researcher and engineer at the Chinese University of Hong Kong, stated in a press release: “Equipping robots with the ability to switch between liquid and solid states will provide them with many more functions.”
The team’s research was published in the journal Matter, where they explained that this new material – “magnetically active solid-liquid phase transition material” – was created by embedding magnetic particles into gallium.
It is noteworthy that gallium is a metal with an extremely low melting point of about 85.6 degrees Fahrenheit (or 29.8 degrees Celsius).
Researchers from the Shenzhen campus of Sun Yat-sen University, Carnegie Mellon University, the Chinese University of Hong Kong, and Zhejiang University created a new phase transition material – named magnetically phase transition material (MPTM) – by embedding neodymium magnetic iron-boron nanoparticles in gallium, a metal with a low melting temperature (29.8 degrees Celsius).
Carmel Majidi, a senior author and mechanical engineer at Carnegie Mellon University, remarked: “The magnetic particles here serve two roles. One is that they make the material responsive to alternating magnetic fields, allowing it to be heated through induction, which causes the phase change. But the magnetic particles also give the robot mobility and the ability to move in response to the magnetic field.”
The researchers drew inspiration for this device from observations of sea cucumbers. They noted that these creatures can alternately switch between “soft” and “hard” states to protect themselves and increase the weight they can carry.
The team’s material can reversibly switch between solid and liquid phases by heating through alternating magnetic fields or through cooling. Before exploring potential applications, the researchers tested the material’s mobility and durability in various contexts.
The robot measures just one millimeter wide and three millimeters tall, but tests conducted by the team determined that it could carry an object weighing 30 times its own mass when in solid form.
To turn it into a liquid, the researchers placed it near a magnet, activating a process called magnetic induction. In other words, the magnets exert a force on the smaller magnetic pieces within the robot, causing them to vibrate, heat up, and generate a current, displacing the surrounding metal as it reaches its melting point.
The scientists could also use different magnetic fields to pull the robot in specific directions, including making it jump by pulling it with a stronger magnetic field from above.
The scientists also demonstrated how this material could function as a smart welding robot for assembling and repairing wireless circuits (by flowing into hard-to-reach circuits and acting as both solder and conductor).
In a test of the control and flexibility of these robots, the research team had two tiny robots transport a light bulb on a circuit board, according to New Scientist. To fuse the light bulb with the circuit board, the robots simply needed to melt and solidify again, allowing the electric current to flow through them and into the bulb.
They conducted a similar experiment inside an artificial stomach, illustrating how these tiny robots could be used to remove foreign objects in situations where human hands or larger robots could not.
In this example, they used magnets to guide the robot to a small object, melt it, and then control the robot to carry the foreign object out.
In biomedical applications, the authors used the robots to retrieve foreign objects from a model stomach and deliver medication on demand into the same stomach.
The researchers also tested an experiment where a Lego-shaped robot could melt into a liquid, escape from a small prison, and then morph back into its original Lego shape.
Pan noted: “Now, we are pushing this material system in more practical ways so that it can address some very specific technical and medical issues.”
Majidi added: “Future research in this field will explore further how these robots can be utilized in biomedical contexts. What we are demonstrating is just a specific proof of concept, but more research is needed to understand how this could actually be used for drug delivery or removing foreign objects.”
