Methods to Enhance Accuracy of an Optical Three-axis Tactile Sensor

Abstract

A robotic manipulator equipped an optical three-axis tactile sensor can detect the distribution of not only vertical but also horizontal force. This sensor is composed of a silicone-rubber sheet, an acrylic plate, a CCD camera and a light source. A silicone-rubber sheet has an array of 8×9 sensor cells consisting of columnar feeler and 2-by-2 conical feelers. Since the reflectance of silicone-rubber is naturally low, the contact area between conical feelers and an acrylic plate cannot be accurately identified. Thus we developed a new silicone-rubber sheet with high reflectance by adding aluminum powder into pre-hardened silicone-rubber. In the experiments, we measured the sensitivity of the present sensor equipped aluminum powder doped silicone-rubber sheet. As a result, the sensitivity of the present tactile sensor was enhanced because clearness of contact contour caused identification of contact area to be more precise.