Vision-Based High-Resolution Tactile Sensor by Using Visual Light Ring

In this letter, a vision-based high-resolution pressure array sensor with sensitivity enhanced by using visual light ring was proposed. The sensor consists of a transparent flexible layer integrating micropillar array and an image sensor with circular array light emitting diodes (LEDs). When pressure is applied to the micropillar, the surface of the substrate around the micropillar produces a concave, and the edges of the concave reflect the light of the LED array to form visual light ring in the image sensor. A relationship between the pressure and the size of the visual light ring was established. The sensitivity using the light ring was increased by three times compared with using deformation of the micropillar. The sensor achieves a high resolution of 625 sensing points per cm2, which was higher than that on the finger of a human. Thus, the sensor will be a competitive solution to artificial tactile system which is of great importance for intelligent robots.