The e-skin reported in the paper was sensitive enough to detect small weights of 15mg (a pressure under 0.5kPa) corresponding to the handling of a small 1mm diameter plastic bead.
The sensor was designed to work in a range up to a maximum of 100 kPa, a little higher than the typical human touch–sensitive range (circa 10 kPa), which would make it robust enough for robotic applications in the case of high-pressure events. The researchers also demonstrated their pixelated hilly capacitor structure with a nine-by-nine sensor array, noting that due to the stretchability of the polyurethane membrane, a force detected on a localized area had limited effect on nearby pixels, providing accurate texture information.
The authors also improved the e-skin's overall sensitivity by spatially distributing the tiny pyramids of the top electrodes following a bioinspired pattern, namely phyllotaxis spirals (an example is the spirals formed by the densely clustered florets of a sunflower).
The researchers anticipate such e-skin could be integrated in many robotic applications, including personalized domestic help, ambulatory and inpatient health care, medical diagnosis, the surgery, industry, and exploratory missions in hard-to-reach places.
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