Swarms of ‘ant-like’ robots lift heavy objects and hurl themselves over obstacles

The findings were published Wednesday, December 18, in the journal Cell Press deviceshowed that these swarms of tiny robots operating under rotating magnetic fields could be used to perform difficult tasks in challenging environments that would be difficult for a single robot to handle, such as providing minimally invasive treatment for clogged arteries and precisely guiding living organisms.

“The high adaptability of the microrobot swarm to the surrounding environment and the high degree of autonomy in swarm control are surprising,” said author Jeong Jae Wie of the Department of Organic and Nanoengineering at Hanyang University in Seoul, South Korea.

Wie and colleagues tested how swarms of microrobots with different assembly configurations performed on a variety of tasks. They found that swarms with high-aspect-ratio components could climb obstacles five times taller than a single microrobot’s body length and hurl themselves over obstacles one after another.

A swarm of 1,000 high-density microrobots formed a raft that floated on the water and wrapped itself around a pill that was 2,000 times heavier than each robot, allowing the swarm to transport the drug through liquids.

On land, a swarm of robots successfully transported cargo 350 times heavier than any human being, while another swarm of microrobots was able to unclog pipes similar to clogged blood vessels. Finally, through rotation and orbital dragging motion, Wei’s team developed a system through which a swarm of robots can guide the movement of small organisms.

Scientists are increasingly interested in studying how swarms of robots collectively achieve goals, inspired by the way ants band together to bridge gaps in their paths or squeeze into the shape of a raft to survive floods. Likewise, working together makes the robot more resistant to failure—even if some members of the team fail to reach a goal, the remaining members continue to perform their programmed actions until enough of them eventually succeed.

“Previous research on swarm robots mainly focused on spherical robots, which come together through point-to-point contact,” Wei said. In this study, researchers designed a swarm of cubic microrobots with stronger magnets

This is attractive due to the large surface area (the entire face of each cube) that can be contacted.

Each microrobot is 600 microns tall and consists of an epoxy resin body embedded with ferromagnetic neodymium iron boron (NdFeB) particles, which allows it to react to magnetic fields and interact with other microrobots. The swarm can assemble itself by using a magnetic field generated by rotating two connected magnets to power the robot. The researchers programmed the robots to fit together in different configurations by changing the angle at which they were magnetized.

“We developed a cost-effective mass production method that uses on-site replica molding and magnetization to ensure uniform geometry and magnetization distribution for consistent performance,” Wie said.

“While the results of this study are promising, clusters require a higher level of autonomy to be ready for real-world applications,” Wei said.

“Magnetic microrobot swarms require external magnetic control and lack the ability to autonomously navigate complex or narrow spaces such as real arteries,” he said. “Future research will focus on increasing the level of autonomy of microrobot swarms, such as for their movement and control. Instant feedback control of trajectories.”