All-fiber curvature sensor based on asymmetric structure

In this paper, an asymmetrically structured curvature sensor fabricated as a biased core fusion bonding, which consists of a PDMS elastomeric material encapsulating an all-fiber Mach-Zehnder interferometer, is proposed to solve the problem of identifying vector bending and twisting. The curvature in the range of 0.2cm-1~0.67cm-1 was realized to recognize the bending direction of the Y-axis and Z-axis in the positive and negative four directions, and the twisting direction of clockwise/counterclockwise in the twisting range of 0-10°. Meanwhile, four repetitive experiments on the repeatability of the sensor were carried out in a constant temperature environment, and the sensitivity error was less than 0.211%. The designed flexible sensor has good linearity and repeatability.It has the advantages of small size,no electromagnetic interference and high sensitivity, which can be applied in the fields of robot intelligent skin and motion monitoring.