When it comes to Schwa's movie "* 2", many people's impression may not be of Mr. Mighty+mechanical skeleton, but of the gorgeous and anti beating liquid metal villain. The villains who were shattered and turned into mercury like creatures that could still be restored inside have become childhood shadows for many people.

Recently, a breakthrough has been made in designing the driving characteristics of liquid metal and its application in robots, and film creativity is moving towards reality.

In recent years, a joint research group consisting of the University of Science and Technology of China, the University of Wollongong in Australia, and Soochow University has begun to study the driving characteristics of liquid metals and their applications in robots, achieving a series of progress.

A joint research team consisting of Associate Professor Zhang Shiwu from the Department of Precision Machinery and Precision Instruments at the University of Science and Technology of China, Professor Li Weihua from the University of Wollongong in Australia, and Associate Professor Li Xiangpeng from the Robotics and Microsystems Center at Soochow University has designed a new type of robot driver based on gallium based room temperature liquid metal, realizing a functional wheeled mobile robot driven by liquid metal.

Recently, the achievement was published in the journal Advanced Materials under the title A Wheeled Robot Driven by a Liquid Metal Droplet (Adv. Mater. 2018, 201805039).

The liquid metal robot "T1000" in the movie "*" opened the dream door for the application of liquid metal in the field of robotics.

The surface properties and physicochemical properties of gallium based liquid metals at room temperature can be transformed, moved, separated, and fused through various energy fields such as electric fields, magnetic fields, and concentration gradient fields or surface modification methods. They have shown great application prospects in fields such as MEMS, microfluidics, biomedicine, and robotics, and have attracted widespread attention.

However, research on the application of liquid metal in the field of robotics is currently limited to using liquid metal droplets as the robot body, and there are no reports on functional robots based on liquid metal.

Gallium based liquid metal at room temperature has enormous surface tension and can exhibit mobility at extremely low electric field power consumption. The joint research team ingeniously combined liquid metal drive and variable center of gravity mechanism to develop a new type of liquid metal robot with simple and compact structure and good driving performance. Researchers have designed an extremely lightweight semi enclosed wheel structure with a superhydrophobic surface, which confines liquid metal droplets inside a narrow wheel body; By cleverly designing a follow-up micro electrode bracket, an external electric field is applied to drive the movement of liquid metal inside the wheel body, thereby continuously changing the center of gravity of the wheeled robot and driving it to roll.

At the same time, researchers conducted dynamic modeling and analysis on the proposed new liquid metal robot, and explored the effects of parameters such as electrolyte concentration, applied voltage, liquid metal volume, and wheel structure on the robot's motion performance through experiments, obtaining the matching of Zuijia parameters for driving motion.

Furthermore, by integrating a battery system, researchers have successfully designed a new type of liquid metal self-propelled wheeled mobile robot. This innovative research is expected to inspire a new type of driving method, which can make up for the shortcomings of traditional robot driving methods (such as motors, hydraulic and pneumatic) such as complex structure, large volume, and low driving energy efficiency, and promote the development of future micro robots and special robot systems.

The author of this paper is Wu Jian, a master's student in the Department of Precision Machinery and Precision Instruments at the University of Science and Technology of China. Zhang Shiwu from the University of Science and Technology of China, Tang Shiyang, a PhD candidate from the University of Wollongong in Australia, and Li Xiangpeng from Suzhou University are co corresponding authors. This project is supported by the National Natural Science Foundation of China.