Meet the team behind the 3D-printed stretchable sensors equipping machines with a sense of touch.
Robots can’t feel. Or can they? Engineering researchers at the University of Minnesota have developed a revolutionary process for 3D printing a stretchable electronic fabric and it’s allowing robots to experience tactile sensation. We reached out to University of Minnesota mechanical engineering associate professor and lead researcher on the study, Michael McAlpine, to find out how the super sensors work.
McAlpine is no stranger to Red Bull or 3D printing. He first achieved international acclaim for integrating electronics and 3D-printed nanomaterials to create a ‘bionic ear’ designed to hear radio frequencies beyond human capability, and featured in our 20 Mightiest Minds on Earth edition of The Red Bulletin way back in 2012. Now he’s tackling a new sense, touch, and his bionic skin may just save lives.
“Putting this type of ‘bionic skin’ on surgical robots would give surgeons the ability to actually feel during minimally invasive surgeries, which would make surgery easier and more precise instead of just using cameras like they do now. These sensors could also make it easier for other robots to walk and interact with their environment,” McAlpine says.
In a further melding of man and machine, future sensors could be printed directly onto human skin for purposes of health monitoring or to protect soldiers in the field from dangerous chemicals or explosives – the ultimate in wearable tech.
“While we haven’t printed on human skin yet, we were able to print on the curved surface of a model hand using our technique,” McAlpine says. “We also interfaced a printed device with the skin and were surprised that the device was so sensitive that it could detect your pulse in real time.”
The applications are pretty impressive, but how exactly does it work? Well, as you might imagine, it’s not your standard 3D printer.
New technology could print directly on human skin© Shuang-Zhuang Guo and Michael McAlpine, University of Minnesota
Conventional 3D printing using liquid plastic is too rigid and hot to print on skin, so McAlpine and his team print their unique sensing material using a one-of-a-kind printer they built in the lab. The multifunctional printer has four nozzles to print the various specialised 'inks' that make up the layers of the device – a base layer of silicone, top and bottom electrodes made of a conducting ink, a coil-shaped pressure sensor and a sacrificial layer that holds the top layer in place while it sets. The supporting sacrificial layer is later washed away in the final manufacturing process.
All the 'inks' used in this process can set at room temperature and the 3D-printed sensors can stretch up to three times their original size.
“With most research, you discover something and then it needs to be scaled up. Sometimes it could be years before it ready for use,” McAlpine explains. “The nice thing about this 3D-printing tool is that the manufacturing is built right into the tool, so this is reality now. We’re starting to integrate these devices directly onto the human body now, and it’s going to completely revolutionise the way people think about 3D printing.”