Soft robot detects damage and self-heals

According to the team at Cornell's Organic Robotics Lab, the robot can identify when and where it was damaged thanks to a technique using stretchable fibre-optic sensors coupled with LED lights, which are able to detect minute changes on the robot’s surface.

“Our lab is always trying to make robots more enduring and agile, so they operate longer with more capabilities,” said Rob Shepherd, associate professor of mechanical and aerospace engineering.

“If you make robots operate for a long time, they’re going to accumulate damage. And so how can we allow them to repair or deal with that damage?”

The sensors are combined with a polyurethane urea elastomer that incorporates hydrogen bonds, for rapid healing, and disulfide exchanges for strength.

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According to the team, the resulting SHeaLDS – self-healing light guides for dynamic sensing – provides a damage-resistant soft robot that can self-heal from cuts at room temperature without any external intervention.

To demonstrate the technology, the researchers installed the SHeaLDS in a soft robot resembling a four-legged starfish and equipped it with feedback control. Researchers then punctured one of its legs six times, after which the robot was able to detect the damage and self-heal each cut in about a minute, they confirmed. The robot could also autonomously adapt its gait based on the damage it sensed.

While the material is sturdy, it is not indestructible – Shepherd described it as having similar properties to human flesh.

“You don’t heal well from burning, or from things with acid or heat, because that will change the chemical properties. But we can do a good job of healing from cuts,” he explained.

Shepherd plans to integrate SHeaLDS with machine learning algorithms capable of recognising tactile events to eventually create ‘a very enduring robot that has a self-healing skin, but uses the same skin to feel its environment to be able to do more tasks’.

The research is published in Science Advances.