Precise shape measurements of rotating workpieces by a single optical sensor

摘要

The precise measurement of the shape of fast rotating workpieces is important at several applicationsrnsuch as lathe monitoring. For such tasks the laser Doppler distance sensor technique was invented byrnthe TU Dresden some years ago. This technique has been realized by two mutually tilted interferencernfringe systems, where the distance is coded in the phase difference between the generatedrninterference signals of two photo detectors. However, due to the speckle effect at rough surfaces,rnrandom envelopes and phase jumps occur disturbing the phase difference estimation. Recently arnscientific breakthrough for the measurement uncertainty budget has been achieved. Via illuminationrnand receiving optics matching the uncertainty of the measurement uncertainty was reduced by aboutrnone magnitude. For displacement measurements of a recurring rough surface an uncertainty of 110rnnm were attained. It enables precise shape measurements, since the lateral velocity and the rotationalrnspeed of rotating objects are determined additionally. This novel sensor technique can bernadvantageously used for the quality control of workpieces inside of a lathe towards the reduction ofrnprocess tolerances, installation times and costs.