Aquatic robot powered by light, rotating magnetic fields developed

Source: Xinhua| 2020-12-11 04:02:52|Editor: huaxia


CHICAGO, Dec. 10 (Xinhua) -- Northwestern University (NU) researchers have developed a first-of-its-kind life-like material that acts as a soft robot. It can walk at human speed, pick up and transport cargo to a new location, climb up hills and even break-dance to release a particle.


Nearly 90 percent water by weight, the centimeter-sized robot moves without complex hardware, hydraulics or electricity. Instead, it is activated by light and walks in the direction of an external rotating magnetic field.


Resembling a four-legged octopus, the robot functions inside a water-filled tank, The secret to the robot's precise movement and agility lies within its water-filled structure and the embedded skeleton of aligned nickel filaments that are ferromagnetic. The soft component is a molecularly designed network with parts that allow it to respond to light, hold or expel water in its interior, and have just the right stiffness to respond rapidly to magnetic fields.


The researchers used chemical synthesis to program the molecules within the hydrogel to respond to light. When exposed to light, the robot's molecules become hydrophobic or repelling water, causing the water molecules to escape. This conversion causes the robot to "come alive" by bending from a flat position to "standing." The researchers discovered that this bending enables the material to respond rapidly to rotating magnetic fields, activating its ability to walk fast. When the light turns off, the molecules revert back to their original state and the robot goes flat, but it is ready anytime for a new cycle of activity under a magnetic field when prompted by an LED.


When exposed to rotating magnetic fields, the embedded skeleton in the bent robot exerts cyclic forces on the soft molecular network and activates the legs. The rotating field can be programmed to navigate the robot along a pre-determined path.


"Using theory and computation, we can calculate the response to light and magnetic fields," said Monica Olvera de la Cruz, deputy director of the Center for Bio-Inspired Energy Science, a NU-based Energy Frontier Research Center funded by the U.S. Department of Energy. "This allows us to predict and program walking trajectories with great accuracy."


These soft robotic materials potentially could be used to create objects for many applications, including chemical production, new tools for environmentally important technologies or as smart biomaterials for highly advanced medicine, the researchers said.


The research was published Wednesday in the journal Science Robotics. 



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