Watch swarms of “ant-like” robots conquer obstacles and carry heavy loads

South Korean scientists have developed swarms of tiny magnetic robots that work together like ants to accomplish Herculean feats, including traversing and picking up objects several times their size.

The results, published on December 18 in Devicesuggest that these swarms of microrobots – operating under a rotating magnetic field – could be used to accomplish difficult tasks in harsh environments that individual robots would struggle to handle, such as offering minimally invasive treatment for blocked arteries and guiding with precision the organisms.

“The high adaptability of the microrobot swarms to their environment and the high level of autonomy in controlling the swarms were surprising,” says author Jeong Jae Wie of the Department of Organic and Nano Engineering at Hanyang University in Seoul, in South Korea.

Wie and his colleagues tested how effectively microrobots swarm with different assembly configurations and perform various tasks. They found that swarms with high aspect ratio assembly could scale an obstacle five times higher than the body length of a single microrobot and rush, one by one, over an obstacle.

A large swarm of 1,000 high-density microrobots formed a raft that floated on water and wrapped around a pill that weighed 2,000 times more than each individual robot, allowing the swarm to transport the drug across the liquid.

On dry land, a swarm of robots managed to carry cargo 350 times heavier than each individual, while another swarm of microrobots managed to unclog tubes that looked like blocked blood vessels. Finally, through rotational motion and orbital dragging, Wie’s team developed a system by which swarms of robots could guide the movements of small organisms.

Scientists are increasingly interested in studying how swarms of robots can collectively achieve goals, taking inspiration from the way ants group together to fill a gap in a path or group together under the shape of a raft to survive floods.

Likewise, working together makes robots more resilient to failure: even if some members of the group don’t reach the goal, the others continue to execute their programmed movements until enough of them they succeed.

“Previous research on swarm robotics has focused on spherical robots, which come together through point-to-point contact,” says Wie. In this study, the researchers designed a swarm composed of cube-shaped microrobots, which share stronger magnetic attractions since larger surfaces – entire faces of each cube – can come into contact.

Each microrobot is 600 micrometers tall and consists of an epoxy body embedded with ferromagnetic neodymium-iron-boron (NdFeB) particles, allowing it to respond to magnetic fields and interact with other microrobots. By powering the robots with a magnetic field generated by the rotation of two connected magnets, the swarm can self-assemble.

The researchers programmed the robots to come together in different configurations by varying the angle at which the robots were magnetized.

“We have developed a cost-effective mass production method using on-site replica casting and magnetization, ensuring uniform geometry and magnetization profiles for consistent performance,” explains Wie.

“While the study results are promising, the swarms will need higher levels of autonomy before they are ready for real-world applications,” says Wie.

“Magnetic microrobot swarms require external magnetic control and do not have the ability to autonomously navigate complex or confined spaces like real arteries,” he says.

“Future research will focus on improving the level of autonomy of microrobot swarms, such as real-time control of their movements and trajectories.”