A new, flexible sensor detects pressure, rubbing and twisting, three of the forces that human skin is able to feel. Although it doesn't work perfectly yet, this is the first flexible sensor that can feel rubbing and twisting, scientifically known as shear and torsion. The new research is part of an effort by many labs to create electronic "skin" for future robots and devices that can distinguish more types of touches.
In this new study, researchers from Seoul National University in South Korea and the University of Illinois at Urbana-Champaign engineered a material with microscopic hairs that are coated in metal, so they're electrically conductive. Then the entire, hairy sheet is covered in a soft plastic. The hairs inside the plastic shift around when the material is touched, which changes the hairs' electrical resistance. By measuring those resistance changes, researchers can determine what kind of touch the sheet felt, Nature News reported.
The researchers created a rectangle of their material that's 8 centimeters (3 inches) long and 5 centimeters (2 inches) wide. When they tested it, they found it could sense a water droplet bouncing on it and two ladybugs walking around on it. Researchers also stuck the material on people's wrists and found the material could measure the pulse. The researchers published their results yesterday (July 29) in the journal Nature Materials.
The system is the first to sense anything about the direction of forces applied to it, instead of just the pressure, Zhenan Bao, a Stanford University materials scientist who was not involved in the study, told Nature News. The hairy sensors' creators still need to improve the computer program that distinguishes the difference between shear and torsion, however, Bao said.
Research into sensitive robot skin is still in its early stages, but we've covered a few interesting efforts from the past year and a half. You can read here about super stretchy pressure sensors, solar-powered electronic skin and a squishy robot finger that distinguishes between textures.