The laser beam of the scanning laser doppler vibrometer is deflected by 2 mirrors which are controlled by the computer. A camera inside the head delivers the picture of the object under test.
On this picture the measurement points can be arranged like with a CAD software. After the setup of points the measurement is done automaticly by the computer.
The scanning laser vibrometer is based on the single point laser vibrometer VibroMet500. The laser beam measures the velocity on the surface of the test object. The velocity signal is measured by a data aquisition system and stored in the computer.
In the picture above the components of a laser scanning system are displayed.
Laser head with mirror unit
Controller box
Data aquisiton
Laptop with control and analysis software
The complete system is very compact and can be carried by one person for example when using a plane.
The laser head includes the laser unit, the mirrors and the video camera. An adjustment of any lenses or optical system is not necessary. The mirrors are controlled by the computer.
The components inside the controller box are the RF amplifier, the demodulator and the output filter. The amplifier increases the signal level, the demodulator makes a velocity signal out of the Doppler signal and with the output low pass filter the frequency range can be limited to reduce noise etc.
The data aquisiton unit for the laser scanner is available as an internal PCI card or as an external USB box.
The control- and analysis sofware has all modules required for a good vibration measurement.
Video frame grabber
Measurement point generator / editor
FFT Analysater
Laser beam control
Operating deflection shape analysis
Animation
optional Modal analysis
The software works with standard PCs or laptops under Windows XP. It also can be used as an office version without any hardware to do the data analysis in the office.
