Abstract
This paper presents an improved touch probe system for higher sensitivity. In this system, three fiber ptic displacement sensors measure displacement and direction of a tip ball of the probe. In general, thin optical fiber improves the sensitivity of the sensor. However, using many fibers and coherent laser light to compensate for decreased light causes interference of the light. In this report, an incoherent LED light with a ball lens solved this problem. When the probe had in contact with a moving plate in Z direction, normalized sensitivity of 50-μm diameter fiber probe was approximately 24 times higher than that of 500-μm fiber probe. However, sensitivities in X and Y directions were less than one hundredth of that in Z direction because of high bending stiffness between the tip and displacement sensor.
