A team of robotics researchers from the University of California San Diego have made a breakthrough in robotics 3D printing by using a commercial machine to embed complex sensors inside robotic limbs and grippers. The project marks a step ahead in 3D printed soft robots and takes us a small step closer to printing an entire robot in a single go.
The ability to 3D print a robot that can walk (or scuttle, or roll) right off the print bed is something that has appealed to robotic researchers for some time. Besides the novelty aspect of the feat, it could also unlock new paths in robot production, reducing the need for human intervention significantly and increasing production rates. In space, for instance, the ability to automatically print a functional robot at a lunar or Mars base could be game-changing.
For now, there is still a ways to go before 3D printers are autonomously producing robots in space, but researchers from UC San Diego have made some important headway in the production of soft robots, finding an innovative solution to a challenge that has plagued them in the past: developing effective sensors for soft robots.
According to the research team, the challenge is caused because soft, flexible robots—which are more flexible and thus safer to work alongside humans than more rigid robots—have complex surfaces and movements that can be difficult to cover with sensors using traditional manufacturing techniques.
By using commercial 3D printing—and specifically Stratasys’ Objet350 Connex 3—and an adapted material, the researchers were able to overcome this challenge and print robotic limbs and grippers with fully integrated sensors.
One of the main breakthroughs achieved by the scientists was adapting an existing material for the project. That is, the team found that they could work with a black resin developed for the multi-material Objet350 Connex 3 system, which was made of carbon particles, that could conduct power to sensors when connected to a power source.
Using this approach, the researchers 3D printed complex sensors using the black resin which were embedded into robotics parts—including a gripper—that were made from a clear polymer.
In tests, the 3D printed prototypes faired fairly well though there is room for improvement. For one, the sensors failed at approximately the same strain as human skin, and, more significantly, the materials used were not optimized for electrical conductivity. The researchers also note that the 3D printed robots require a lot of post-processing before they are functional, including careful washing and drying.
Still, the achievement by the researchers is worth highlighting, especially as they continue their work. The team is also hopeful that as the 3D printing materials market grows, more conductive options will be developed.
As the researchers commented: “Embedded printing of sensors is a powerful process that could enable and enhance seamless integration of sensors into soft robots, but there does not yet exist a suitable, commercially available, easy to use platform that allows users to simultaneously print soft actuators and sensors.”