A Robotic Finger Equipped with an Optical Three-Axis Tactile Sensor

Abstract

In the preceding paper we developed an optical three-axis tactile sensor capable of acquiring normal and shearing force, with the aim of mounting it on a robotic finger. Normal force and shearing force applied to the sensing element were detected separately ; when we examined repeatability of the present tactile sensor with 1 000 loading-unloading cycles, the respective error of the normal forces was 2%. In the present paper, the three-axis tactile sensor is mounted on a robotic finger of 3 degrees of freedom to evaluate the tactile sensor for dexterous hands. In a series of experiments, three kinds of experiments are performed. First, the robotic hand touches and scans on flat specimens to evaluate ability of surface condition. Second, it detects contour of parallelepiped and cylindrical objects. Finally, it manipulates a parallelepiped case put on a table by means of sliding on the table. Since the present robotic hand was able to perform the abovementioned three tasks with appropriate precision, we prospected that the hand was applicable to the dexterous hand in the subsequent studies.