Laser scanning vibrometry
The laser scanning vibrometry is a fast imaging method for contactless measurement of vibrations , for example in the automotive, aerospace and engineering, in the microsystem and data technology and in the quality and production control. The optimization of vibration behavior and acoustics (e.g. operational vibration analysis ) has become an important goal of product development in many of these areas, as the dynamic and acoustic properties of products are among the essential quality features.
The functional principle is based on laser Doppler vibrometry : The vibration speed and displacement are determined from the laser light that is backscattered by a vibrating structure . In a scanning vibrometer, the laser Doppler vibrometer is integrated in a measuring head with a scanner-mirror unit and a video camera. During the measurement, the laser beam is scanned over the surface of the measurement object and sequentially delivers a series of single point measurements with a very high spatial resolution. From these sequentially measured vibration data, the simultaneous movement of the structure can be determined and visualized either in the time domain or the operating vibration forms in the frequency bands of interest from the analysis in the frequency domain . In contrast to tactile measurement methods, the vibration to be examined is not influenced by the measurement process. The measuring ranges accessible with today's vibrometers completely cover the entire area of technically relevant vibrations. With vibrometry, on the one hand, movements of microstructures with oscillation paths of a few pm at frequencies of up to 30 MHz (and thus v = 0.1 m / s) can be analyzed, on the other hand, rapid processes in Formula 1 engines with oscillation speeds of 30 m / s.
A 3D scanning vibrometer combines three measuring heads that detect the vibrating movement from different spatial directions and thus completely determine the 3D vibration vector. In the 3D representation of the vibration data, the vibrations of the measurement object can be observed spatially or individually in the x, y and z directions and in-plane and out-of-plane vector components can be clearly distinguished from one another.
Automated laser scanning vibrometry
By mounting the three laser Doppler vibrometers on a rail- mounted robot arm, the degree of automation of the vibration analysis can be further increased. After appropriate preparation, the measurement object is analyzed fully automatically without having to be controlled or supervised.