Print-in-one robots come a step closer with sensors embedded in soft machines

‘Get-up-and-go-bots’ that trundle off the production line after being built in one 3D-printing session have come a step closer after researchers successfully printed a machine with built-in sensors.

Print-in-one robots are desirable because they could be produced much more quickly than conventional machines. They could even be built without human supervision – on the Moon or Mars, for example.

One of the main roadblocks is the difficulty of developing effective sensors for soft robots, a growing field thanks to their durability and flexibility. Bendable materials have complex surfaces and movements, making them difficult to cover with sensors made with traditional manufacturing techniques.

Researchers at University of California San Diego have tackled this issue and led the way towards get-up-and-go-bots, however, by using a commercially-available Stratasys 3D printer and a black printing resin that they realised contains conductive carbon powder that can conduct power to sensors when connected to a power source.

The roboticists used the black resin to manufacture complex sensors that were embedded within robotic parts made of clear polymer. When stretched, the sensors failed at approximately the same strain as skin. The team designed and manufactured several prototypes, including a gripper.

“Embedded printing of sensors is a powerful process that could enable and enhance seamless integration of sensors into soft robots,” the researchers said. However, they added: “There does not yet exist a suitable, commercially available, easy-to-use platform that allows users to simultaneously print soft actuators and sensors.”

The polymers used were not designed to conduct electricity, so do not have optimal performance. The printed robots also need post-processing including careful washing before they can be used.

The research was published in Frontiers in Robotics and AI.