Undulating electroluminescent mood robot could serve healthcare, transportation applications
Remember mood rings? They appeared in the 1970s and ostensibly changed color depending on the mood of the wearer. (Actually, they incorporated thermochromic liquid crystals and changed color with temperature). Next up—and much more practical—might be mood robots, which in a healthcare environment, for example, could change color in reaction to patients’ moods.
Such a robot hasn’t been built, but a team of Cornell graduate students, led by Rob Shepherd, assistant professor of mechanical and aerospace engineering, has taken the first step by developing a flexible electroluminescent skin that stretches to more than six times its original size while still emitting light. The team envisions advances in transportation, electronic communication, and other areas as well as health care.
The material incorporates what the researchers call a hyper-elastic light-emitting capacitor (HLEC), which, they say, can endure more than twice the strain of previously tested stretchable displays. “This material can stretch with the body of a soft robot, and that’s what our group does,” Shepherd said, as reported at Newswise. “It allows robots to change their color, and it also allows displays to change their shape.”
HELC consists of layers of transparent hydrogel electrodes sandwiching an insulating elastomer sheet. The elastomer changes luminance and capacitance when stretched, rolled, and otherwise deformed.
“We can take these pixels that change color and put them on these robots, and now we have the ability to change their color,” Shepherd said. “Why is that important? For one thing, when robots become more and more a part of our lives, the ability for them to have emotional connection with us will be important. So to be able to change their color in response to mood or the tone of the room we believe is going to be important for human-robot interactions.”
The researchers have not yet implemented a color-changing healthcare robot. What they have built is a crawling, undulating soft robot made up of three six-layer HELC panels, with the top four layers providing the illumination and the bottom two layers serving as pneumatic actuators. You can see a video at Newswise.
The group’s paper, “Highly Stretchable Electroluminescent Skin for Optical Signaling and Tactile Sensing,” is published in the March 3 online edition of the journal Science.
