Development of a miniaturized model of a finger shaped tactile sensor using an optical waveguide

A finger-shaped tactile sensor which was previously proposed and investigated using a scaled-up model was miniaturized and its signal processing speed was improved. The miniaturized tactile sensor consists of a hemispherical optical waveguide with an elastic cover, a FOP (fiber optics plate), a PSD (position sensitive detector), and infrared LEDs (light emitting diodes) as the light source. When an object comes in contact with the sensor, the elastic cover is depressed and light from the LEDs which maintains a total internal reflection on the surface of the waveguide will be scattered at the contact location of the waveguide and the cover. The scattered light is transmitted to the PSD through the FOP. The contact location and the surface normal of the object are determined from the output of the PSD. Fundamental characteristics of the sensor are evaluated through experiments using the miniaturized sensor model