Diaphragm-Micro-Stylus-Based Fiber Bragg Grating Tactile Sensor

We propose a simple and novel circular diaphragm-micro-stylus based single fiber Bragg grating (FBG) tactile sensor for reading Standard English Grade-1 Braille cells. The surface protrusions on the cells are transduced into strain variations on the FBG sensor, bonded along the line of symmetry of the diaphragm, by a free, vertically moving Micro-Stylus (MS). The tension mode of the diaphragm and the mass of the micro-styli are varied to optimize the sensing properties of the system. The maximum sensitivity of 1.786nm/mm is exhibited by the sensor system with the highest mass of the MS (MS-1; 167mg) in the highest tension mode (770με). The repeatability error and resolution of the sensor in the aforementioned configurations are found to be 0.028nm and 559nm respectively. The proposed sensor system displayed good linearity, repeatability, high resolution, and easily adjustable sensitivity in the present scenario.