Although they have not yet reached their capacity in science fiction movies, there are robots that can do very complex tasks. For example, soft-bodied robots can enter tight spaces; however, what they can do there is still limited. They are also very difficult to control.
From the Chinese University of Hong Kong, Dr. A team led by Chengfeng Pan has built a robot that can change states to whatever is needed most, and released a video summarizing it. The robot’s escape from prison by doing this can trigger your fears. Because what you will see in the video will surely remind you of the Terminator 2 movie.
But it should not be forgotten that robots like this can also provide life-saving services that others cannot. “Giving robots the ability to switch between liquid and solid states makes them more functional,” Pan said in a statement.
This feat relies on a material that the authors refer to as a “magnetoactive solid-liquid phase transition machine,” which can switch between solid and liquid under the influence of a magnetic field. To do this, the researchers needed a metal that turned into a liquid at near room temperature. The solidification conditions for mercury are very cold, and it takes a lot of heat to liquefy most other metals. However, gallium was well suited, with a melting point of just 29.8 degrees.
The team added neodymium-iron-boron magnetic microparticles from Carnegie Mellon University to the gallium. Professor Carmel Majidi says these are two tasks. “They sensitize the material to an alternating magnetic field, so you can heat the material through induction and cause a phase change,” said Majidi, noting that induction heats gallium between 25 and 35 °C, “but magnetic particles also give robots mobility and movement in response to the magnetic field. It gives me the ability to do it,” he added.
You can watch the robot’s shape-shifting escape from prison in the video below:
Phase-change materials have been made before, but external heat sources or electric currents are needed to transform them. Neither is ideal if you want to send the robot somewhere hard to reach, such as inside the human body.
In addition to the achievements in the video, the article reports that its tiny robots can jump 21-millimeter trenches and climb walls while in solid state, but subdivide to get around objects before recombining in liquid state. “We are now exploring more practical uses of this material system to solve some very specific medical and engineering problems,” says Pan.
Human body temperature requires the use of a metal with a higher melting point than gallium, and phase change takes longer in liquids than in air because heat is lost more quickly to the environment. However, the potential exists for rapid delivery of drugs to the stomach or removal of foreign bodies from the stomach.
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