Fiber Bragg grating-based fingertip tactile sensors for normal/shear forces and temperature detection

To facilitate the acquisition of relevant tactile information from physical interaction, natural tactile perception requires tactile sensors adapted to tactile carriers. Herein, we propose a flexible tactile sensor based on fiber optic grating normal/shear forces detection. In order to develop a sensor with high sensitivity, real-time response, and good stability, the fiber Bragg gratings (FBGs) are deliberately embedded at off-axis positions of cylindrical shape silicone elastomer, the sensor can feedback both purely normal forces through FBG1 and purely shear forces through FBG1＆2. A third FBG is a strain-free sensor intended for temperature compensation. The experimental results show that the flexible tactile sensor is capable of simultaneous temperature and normal force or shear force measurement. The proposed method provides a new approach for multi-dimensional tactile sensing.