Sensing Characteristics of an Experimental CT Tactile Sensor

The CT (Computed tomography) method is very effective for making thinner optical waveguide-type tactile sensors. In a previous paper, the authors established the architecture of a CT tactile sensor and evaluated its principle using a series of computer simulations. As a result, the LU decomposition method showed better noise robustness compared to the ART method. On the basis of the simulations, we develop an experimental CT tactile sensor comprised of infrared diodes, phototransistors, an acrylic plate and a black rubber sheet. In the present study, the LU decomposition method is employed and we determine the validity of the algorithm by examining use of a loading machine produced for the CT tactile sensor. In a series of experiments, it is found that absorption of light intensity increases monotonically with increase of applied force and that the present reconstruction method can be applied to not only simply but also multiply connected contact domains. The estimated position of the pressure centroid possesses a rather large error of 4.9 mm, which is 10.8% of a segment of the sensing area.