Hetero-core fiber optic tactile sensor for accurate discrimination of texture and hardness

Abstract

This paper describes a novel tactile sensor using a hetero-core fiber optic sensor for detecting particular tactile information of surface texture and hardness. The hetero-core fiber optic sensor consists of two single-mode fibers with different core diameters, which can detect soft bending on a sensor portion, moreover being tolerant to several environmental fluctuation such as corrosion, temperature fluctuation and electromagnetic interference. The hetero-core fiber optic tactile sensor was designed in order to detect contact force by means of the hetero-core fiber optic sensor implanted in three-point bending structure. Force property of the tactile sensor was experimentally confirmed to be highly-sensitive in reaction to force given in the range of 0.01 - 5.0 N. Therefore, it was observed that the tactile sensor could detect minute level change of surface texture in the height of 0.01 mm with the spatial accuracy within 0.10 mm. In addition, the degree of hardness and the other physical property of viscoelasticity could be detected by pushing the tactile sensor on materials. As a result, it was successfully performed that the proposed tactile sensor could detect various kinds of tactile information with high sensitivity.