Smart Micro Robots

Researchers at Paul Scherrer Institute PSI and ETH Zurich have developed a micromachine capable of performing different actions. First, nanomagnets found in the components of micro robots are programmed magnetically, and then various movements are controlled by magnetic fields.

These machines, measuring only a few micrometres in size, could be used to perform small operations in the human body. The researchers published their results in the scientific journal Nature. The robot, measuring only a few micrometres, resembles a paper bird made using Japanese paper folding art, origami.

However, unlike a paper structure, the robot can move without any visible force, as if by magic. It flaps its wings or bends its neck and pulls its head back, all these actions being made possible through magnetism.

Researchers at Paul Scherrer Institute PSI and ETH Zurich built the micromachine with materials containing small nanomagnets. These nanomagnets can be programmed to assume a specific magnetic orientation.

When the programmed nanomagnets are then exposed to a magnetic field, specific forces act upon them. If these magnets are placed in flexible components, the forces acting on them allow the components to move.

Programming Nanomagnets

Nanomagnets can be reprogrammed repeatedly. This reprogramming results in different forces and enables new movements. For the construction of the microbot, researchers manufactured cobalt magnet arrays on thin silicon nitride layers.

Bird-shaped microbots constructed from this material can then perform various movements such as wing flapping, hanging, rotating or lateral sliding.

Laura Heyderman, Head of the Multiscale Materials Experiments Laboratory at PSI and Professor of Mesoscopic Systems at ETH Zurich, says, "The movements performed by the microbot happen within milliseconds. However, programming the nanomagnets takes only a few nanoseconds.

This makes it possible to program different movements one after another. This shows that the small micro bird can first flap its wings, then move sideways and then flap its wings again. When needed, the bird can also remain stationary," says Heyderman.

Intelligent Microrobots

This new concept is an important step towards micro and nanorobots that not only store information to perform a specific action but can also be reprogrammed to perform different tasks.

Bradley Nelson, Head of the Department of Mechanical and Process Engineering at ETH Zurich, said, "In the future, one could imagine an autonomous micromachine circulating in human blood vessels and performing biomedical tasks such as killing cancer cells."

Tianyun Huang, a researcher from the Institute of Robotics and Intelligent Systems at ETH Zurich, said "Other application areas can also be considered, such as flexible microelectronics or microlenses capable of changing their optical properties".

Additionally, applications where surface properties change are also possible. Jizhai Cui, an engineer and researcher working at the Mesoscopic Systems Lab, shares his view by saying "For example, it could be used to create surfaces that can be wetted with water or water-repellent".

Image Caption: A scanning electron microscope image shows the arrangement of nanoscale magnets with a structure similar to a bird. The magnets can be magnetised in different directions parallel to the colour bars. By programming their magnetisation, researchers enable the bird to perform different movements in a magnetic field. (Photo: Paul Scherrer Institute / Swiss Federal Institute of Technology, Zurich)