Self-healing soft robots are a significant engineering breakthrough.
Roboticists have designed soft robots that can heal themselves.
Researchers at the Vrije Universiteit Brussel (VUB) have extended this self-healing property specifically to soft robots. These are robots constructed from flexible materials that enable them to be used to grab delicate objects in the food industry or in minimally invasive surgery. They play an important role in rehabilitation and arm prostheses.
“A robot is very complex and difficult to repair. And the soft robots are particularly susceptible to sharp objects and high pressure” explains professor Bram Vanderborght of VUB, one of the five researchers behind the project. “This research is the first step in introducing self-healing materials in soft robotics, which we think will start a whole new research field of self-healing robotics,” Vanderborght continues.
During their experiments, the team built soft robots made entirely from rubbery polymers. When damaged, these materials first recovered their original shape and then healed completely. “This principle was tested on three self-healing robotic components: a gripper used for robots to pick up items, a robot hand, and an artificial muscle,” he continues. “Realistic damage could be healed completely without leaving any weak spot. The prototypes were able to fully resume their tasks.”
Once a soft robot is damaged, the material is able to heal after being heated for 40 minutes at 80°C. After 24 hours at 25°C, the damaged robot’s strength and flexibility would also be restored.
The polymer material used does this because it consists of a network of cross links that allow the Diels-Alder reaction to take place. This reaction allows new bonds to be made by the molecules. “By applying heat, those cross-links will break, which gives the polymer material more mobility. This mobility allows the molecules to close the gap made by the damage. When healed the material has to be cooled down, during which the initial properties are almost completely regained,” explains Vanderborght.
The team, which has backing from the European Research Council, also has big hopes for the impact of this research. Collaborator Seppe Terryn, who has worked on the project since 2014, says: “We hope that humans will develop a new kind of trust in robots, knowing that their functional performance is not depending on the human detection and repair of damages.”
Indeed, the gap in this field of industry makes this research particularly exciting. “The inability to heal is one of the major shortcomings of our mechanical systems versus their biological counterparts,” confirms electrical engineering expert, professor Russell Tedrake of the Massachusetts Institute of Technology. “Suitable progress in this direction could substantially improve the robustness of our machines.”
Tedrake also questions the extent to which this technology could be extended to other objects in the future, “such as self-repairing tyres for cars”.
However, more immediately, the VUB team is hoping to work towards adding a sensor network to detect the health status of robots and even new materials.Discover More