Self-healing robot recovers from being stabbed then walks off

A simple robot has sensors that can detect when they are damaged, stop the robot, self-heal and instruct the robot to start moving again

By Karmela Padavic-Callaghan

A flexible quadruped robot can sense when it is damaged and stop moving until it heals.

Robots made of soft and deformable materials can change their body shape and imitate biological tissues like muscles for prosthetics. But because they are soft, they can be susceptible to damage. Hedan Bai at Northwestern University in Illinois and her colleagues made a simple soft robot that can detect when it is harmed and then mend itself before continuing to move.

The robot is about 12 centimetres long and shaped like the letter X. It moves using compressed air that is pushed through its body, making it undulate and lift its four legs. The top of the robot is covered in a layer of self-healing sensors made from a transparent rubbery material that track the robot’s motion. If the sensor is cut, its exposed sides become chemically reactive, allowing it to fuse back together.

The researchers tested the robot’s “damage intelligence” by stabbing a sensor on its leg six times. It stopped for about a minute to let the sensor heal after each cut then resumed moving. In another experiment, they stabbed the sensors on the robot’s legs one at a time. After each stab, the robot stopped to heal for a few minutes and then changed its gait in response to the damage. “We really tried to torture these sensors as much as we can,” says Bai.

Bram Vanderborght at the Free University of Brussels in Belgium says that perfecting self-healing components for robots would make them more sustainable since only parts that are damaged too severely to self-heal – like if they are burned or covered in chemicals, for example – will have to be discarded.

Eventually, soft robots with self-healing parts could be used to work in hazardous environments, while the self-healing sensors themselves could be integrated into wearable devices, like space suits where they could react to being damaged by space debris.

Journal reference: Science Advances, DOI: 10.1126/sciadv.abo3977