An Experimental Optical Three-Axis Tactile Sensor for Micro Machines

Abstract

This paper described a micro optical three-axis tactile sensor capable of sensing not only vertical force but also horizontal force. The vertical force was detected from the integrated gray scale values of bright pixel emitted from the contact area of conical feelers. The conical feelers were formed on the rubber sheet surface keeping contact with an optical waveguide plate. The horizontal force was detected from the horizontal displacement of the conical feelers. In the experiments, a precise multi-axial loading machine was developed to measure sensing characteristics of the present sensor. It was found that the vertical force was specified uniquely under combined force conditions and that the horizontal force was specified by modifying the relationship between the horizontal force and the horizontal displacement on the basis of vertical force. From the experimental results calibration coefficients were identified to transform the integrated of gray scale values into vertical force and to transform the horizontal displacement into the horizontal force.