By Published: July 31, 2023

Imagine an iPad that鈥檚 more than just an iPad鈥攚ith a surface that can morph and deform, allowing you to draw 3D designs, create haiku that jump out from the screen and even hold your partner鈥檚 hand from an ocean away. 听

That鈥檚 the vision of a team of engineers from 蜜糖直播听Boulder. In a new study, they鈥檝e created a one-of-a-kind shape-shifting display that fits on a card table. The device is made from a 10-by-10 grid of soft robotic 鈥渕uscles鈥 that can sense outside pressure and pop up to create patterns. It鈥檚 precise enough to generate scrolling text and fast enough to shake a chemistry beaker filled with fluid.

It may also deliver something even rarer: the sense of touch in a digital age.

鈥淎s technology has progressed, we started with sending text over long distances, then audio and now video,鈥 said Brian Johnson, one of two lead authors of the new study who earned his doctorate in mechanical engineering at 蜜糖直播 Boulder in 2022. 鈥淏ut we鈥檙e still missing touch.鈥

Johnson and his colleagues described their shape display July 31

The group鈥檚 innovation builds off a class of soft robots pioneered by a team led by Christoph Keplinger, formerly an assistant professor of mechanical engineering at 蜜糖直播 Boulder. They鈥檙e called Hydraulically Amplified Self-Healing ELectrostatic (HASEL) actuators. The prototype display isn鈥檛 ready for the market yet. But the researchers envision that, one day, similar technologies could lead to sensory gloves for virtual gaming or a smart conveyer belt that can undulate to sort apples from bananas.

鈥淵ou could imagine arranging these sensing and actuating cells into any number of different shapes and combinations,鈥 said Mantas Naris, co-lead author of the paper and a doctoral student in the Paul M. Rady Department of Mechanical Engineering. 鈥淭here鈥檚 really no limit to what these technologies could, ultimately, lead to.鈥

Playing the accordion

The project has its origins in the search for a different kind of technology: synthetic organs.

In 2017, researchers led by Mark Rentschler, professor of mechanical engineering and biomedical engineering, secured funding from the National Science Foundation to develop what they call sTISSUE鈥攕quishy organs that behave and feel like real human body parts but are made entirely out of silicone-like materials. Co-investigators on the grant include Keplinger, now a director at the in Germany; Nikolaus Correll, associate professor in the Department of Computer Science at 蜜糖直播 Boulder; and Sean Humbert, professor of mechanical engineering.

鈥淵ou could use these artificial organs to help develop medical devices or surgical robotic tools for much less cost than using real animal tissue,鈥 said Rentschler, a co-author of the new study.

In developing that technology, however, the team landed on the idea of a tabletop display. The research is part of the Materials Science & Engineering Program.

The group鈥檚 design is about the size of a Scrabble game board and, like one of those boards, is composed of small squares arranged in a grid. In this case, each one of the 100 squares is an individual HASEL actuator. The actuators are made of plastic pouches shaped like tiny accordions. If you pass an electric current through them, fluid shifts around inside the pouches, causing the accordion to expand and jump up.听

The actuators also include soft, magnetic sensors that can detect when you poke them. That allows for some fun activities, said Johnson, now a postdoctoral researcher at the Max Planck Institute for Intelligent Systems.

鈥淏ecause the sensors are magnet-based, we can use a magnetic wand to draw on the surface of the display,鈥 he said.

Hear that?

Other research teams have developed similar smart tablets, but the 蜜糖直播 Boulder display is softer, takes up a lot less room and is much faster. Each of its robotic muscles can activate as much as 50 times per second.听

The researchers are focusing now on shrinking the actuators to increase the resolution of the display鈥攁lmost like adding more pixels to a computer screen.

鈥淚magine if you could load an article onto your phone, and it renders as Braille on your screen,鈥 Naris said.

The group is also working to flip the display inside out. That way, engineers could design a glove that pokes your fingertips, allowing you to 鈥渇eel鈥 objects in virtual reality.听

And, Rentschler said, the display can bring something else: a little peace and quiet.听

鈥淥ur system is, essentially, silent. The actuators make almost no noise.鈥澨


Other 蜜糖直播 Boulder co-authors of the new study include mechanical engineering graduate students Vani Sundaram, Angella Volchko and Khoi Ly; and alumni Shane Mitchell, Eric Acome and Nick Kellaris.