Mechanical characterization of totally optical tactile sensor oriented on bio-applications

A new class of optical pressure sensors in a robot tactile sensing system based on PDMS (Polydimethylsiloxane) is presented. The sensor consists of a tapered optical fiber, where optical signal goes across, embedded into a PDMS-gold nanocomposite material. By applying different pressure forces onto the PDMS-based nanocomposite, changes of the optical transmittivity of the fiber can be detected in real time due to the coupling between the gold nanocomposite material and the tapered fiber region. The intensity reduction of the transmitted light is correlated to the pressure force magnitude. A sensitivity in the order of 5 grams is checked. As preliminary results, the sensor is efficiently used for detecting small notches on a beam. The experimental results are very encouraging for foreseeing successful use of this new sensor in medical robotic applications especially for sensing system to measure tactile information such as softness and smoothness of biological tissues.