Laser Doppler sensor employing a single fan-shaped interference fringe system for distance and shape measurement of laterally moving objects

Abstract

For monitoring the position and shape of fast moving and, especially, rotating objects such as turbo machine rotors, contactless and compact sensors with a high measurement rate as well as high precision are required. We present for the first time, to the best of our knowledge, a novel laser Doppler sensor employing a single fan-shaped interference fringe system, which allows measuring for the position and shape of fast moving solid bodies with known tangential velocity. It is shown theoretically as well as experimentally that this sensor offers concurrently high position resolution and high temporal resolution in contrast to conventional measurement techniques, since its measurement uncertainty is, in principle, independent of the object velocity. Moreover, it can be built very compact, because it features low complexity. To prove its operational capability and its potential for practical applications, radial and axial shape measurements of rotating bodies are demonstrated in comparison with triangulation. An average position resolution of about 2 microm could be achieved.

Dynamic Rotor Deformation and Vibration Monitoring Using a Non-Incremental Laser Doppler Distance Sensor

“…In practice, there are many applications in particular concerning rotating objects, where the tangential velocity v of the object surface is known very well [19]. For example at motors or turbo machines, the current rotational frequency f rot is generally measured by speed sensors inside the machine.…”

“…only one fan-shaped interference fringe system [19]. only one fan-shaped interference fringe system [19].…”

“…The S-LDDS features nearly the same measurement properties as the complete LDDS except for the necessity of knowing the tangential object velocity v. For details see [19].…”

Miniaturized nonincremental interferometric fiber-optic distance sensor for turning process monitoring

“…[6][7][8][9] Considering both measured quantities and applying the signal evaluation discribed in Sec. [6][7][8][9] Considering both measured quantities and applying the signal evaluation discribed in Sec.…”

“…[6][7][8][9] Considering both measured quantities and applying the signal evaluation discribed in Sec. 7,8,10 In this paper we present for the first time results of inprocess measurements at a metal working lathe with a miniaturized and robust LDD sensor. 9 Hence, only one optical access to the workpiece and a single sensor suffice to measure the absolute 3-D shape of the workpiece.…”