Sensitivity-enhancing All-in-type Optical Three-axis Tactile Sensor Mounted on Articulated Robotic Fingers

In a previous study, we developed an all-in-type optical three-axis tactile sensor to address two issues: the first is to be able to use external devices such as a CCD camera and light source; the other is the insensible zone. We miniaturized its whole structure through adoption of a CMOS board camera equipped with LEDs. Since a USB is installed in the CMOS camera as an interface, an additional image processing board is not required. Furthermore, it is equipped with a rubber dome including a sensing element array to remove the insensible zone because rubber is filled in between the sensing elements. However, even if it accepted under around 1-N force, no output of brightness appeared. In this paper, we enhance the characteristic in the low level applied force through improvement of image processing. Furthermore, the present sensor showed higher output level of normal and tangential forces through a series of experiments comparing the present and ordinal three-axis tactile sensors.