Making robots more human by detecting human emotions
April 30, 2015
If robots could detect human emotions, it might make them more “human.” That’s the premise of new research by Korean scientists, who have developed simple, low-cost, ultra-sensitive wearable strain sensors that can detect facial expressions.
This kind if detection is normally done with vision sensors connected to a computer, with facial-analysis algorithms, but such systems are expensive and have low mobility and high complexity, the researchers note in a paper published in ACS Nano.
Instead, the researchers created a stretchable, transparent sensor by layering a carbon-nanotube film on two different kinds of electrically conductive elastomers. They found that changes in resistance values could indicate whether subjects were laughing or crying and where they were looking, based on characteristic patterns of resistance change.
The sensors could also have applications in monitoring heartbeats, breathing, dysphagia (difficulty swallowing),and other health-related cues, the researchers suggest.
The work was funded by the National Research Foundation of Korea.
Abstract of Stretchable, Transparent, Ultrasensitive, and Patchable Strain Sensor for Human–Machine Interfaces Comprising a Nanohybrid of Carbon Nanotubes and Conductive Elastomers
Interactivity between humans and smart systems, including wearable, body-attachable, or implantable platforms, can be enhanced by realization of multifunctional human–machine interfaces, where a variety of sensors collect information about the surrounding environment, intentions, or physiological conditions of the human to which they are attached. Here, we describe a stretchable, transparent, ultrasensitive, and patchable strain sensor that is made of a novel sandwich-like stacked piezoresisitive nanohybrid film of single-wall carbon nanotubes (SWCNTs) and a conductive elastomeric composite of polyurethane (PU)-poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS). This sensor, which can detect small strains on human skin, was created using environmentally benign water-based solution processing. We attributed the tunability of strain sensitivity (i.e., gauge factor), stability, and optical transparency to enhanced formation of percolating networks between conductive SWCNTs and PEDOT phases at interfaces in the stacked PU-PEDOT:PSS/SWCNT/PU-PEDOT:PSS structure. The mechanical stability, high stretchability of up to 100%, optical transparency of 62%, and gauge factor of 62 suggested that when attached to the skin of the face, this sensor would be able to detect small strains induced by emotional expressions such as laughing and crying, as well as eye movement, and we confirmed this experimentally.