REAL-TIME OPTICAL MEASUREMENT OF POSITION

This paper presents a sensor system, called CD-sensor (Compact Disc pick-up sensor system for measuring position of mechanical parts), used to measure in real time the angular or translatory position of a body. The CD-sensor system does not require a special made reference. This makes it light weight and small in size. Those are essential properties for integration in a mechatronical system. The measuring head consists of a pick-up from a Compact Disc Player System. The CD-sensor uses the ability of the pick-up to measure reflection from an arbitrary (solid) surface. The reflection profile from the measurement object is prestored and works as reference for subsequent measurement of position. Equations are derived for calculation. Finally, the CD-sensor performances are tested for angular and translatory motions to demonstrate the feasibility to measure in real-time positions accurately.