Technique uses magnets, light to control and reconfigure soft robots: Study

Researchers have developed a technique that allows them to remotely control the movement of robots, lock them into position for as long as needed and reconfigure them later into new shapes, with the help of light and magnetic fields.

"We're particularly excited about the reconfigurability. By engineering the properties of the material, we can control the soft robot's movement remotely; we can get it to hold a given shape; we can then return the robot to its original shape or further modify its movement, and we can do this repeatedly," said Joe Tracy, the corresponding author of a paper on the study published in the journal 'Science Advances.'

The development said Tracy is valuable, in terms of this technology's utility in biomedical or aerospace applications.

Researchers used robots made of a polymer embedded with magnetic iron microparticles.

Under normal conditions, the material is relatively stiff and holds its shape but heating up the material using light from a light-emitting diode (LED), makes the polymer pliable.

Once pliable, researchers demonstrated that they could control the shape of the robot remotely by applying a magnetic field. After forming the desired shape, researchers could remove the LED light, allowing the robot to resume its original stiffness effectively locking the shape in place.

By applying the light a second time and removing the magnetic field, the researchers could get the soft robots to return to their original shapes or move the robots or get them to assume new shapes.

In experimental testing, the researchers demonstrated that these soft robots could be used to form "grabbers" for lifting and transporting objects. The soft robots could also be used as cantilevers or folded into "flowers" with petals that bend in different directions.

"We are not limited to binary configurations, such as a grabber being either open or closed. We can control the light to ensure that a robot will hold its shape at any point," said Jessica Liu, first author of the paper.

In addition, the researchers developed a computational model that can be used to streamline the soft robot design process.

The model allows them to finetune a robot's shape, polymer thickness, the abundance of iron microparticles in the polymer, and the size and direction of the required magnetic field before constructing a prototype to accomplish a specific task.

"Next steps include optimising the polymer for different applications. For example, engineering polymers that respond at different temperatures in order to meet the needs of specific applications," Tracy said.