Scanning Laser Vibrometer

The scanning laser vibrometer is based on the single point laser vibrometer VibroMet500

Description

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.

Method

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.

Components

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 on person for example when using a plane.

Laser Head

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.

Controller

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.

Data Aquisition

The data aquisiton unit for the laser scanner is available as an internal PCI card or as an external USB box.

 Technical data

    •  Number of channels:
    • AD converter:
    • Frequency range:
    • Max. Input voltage:
    • Couppling:
    • Anti-Aliasing filter:

    • 4 channel and more
    • 20 Bit / 16 Bit
    • 0 – 20 kHz adjustable
    • 10mV – 10V adjustable
    • AC, DC, ICP source(2mA)
    • Automaticly tracked

Scanner Software

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.