Optical Sensor Using Light Intensity Modulation : Feasibility Test

This paper describes the optical measuring method to detect a distance between a tool and a work piece. The sensing apparatus consists of a laserdiode, a quadrant photodiode and a signal analysis circuit. It measures various light intensity as the target tool is moving. Especially, it is possible to measure the tool position not only at Y-axis and Z-axis but also at X-axis by using laser beam as a source which has a constant radiation angle. Also, this paper proposes a numerical formula that determines the tool position at X-axis based on the size of tool shadow. The numerical formula would be useful aligning the tool axis with the work piece because we can exactly control the tool position.