Experimental validation of a newly designed 6 degrees of freedom scanning laser head: Application to three-dimensional beam structure

Abstract

A new scanning laser head is designed to use single Laser Doppler Vibrometer (LDV) for performing measurements up to 6 degrees of freedom (DOF) at a target. The scanning head is supported by a rotating hollow shaft, which allows the laser beam to travel up to the scanning head from an opposite direction where an LDV is set up. The scanning head is made of a set of two mirrors, which deflects the laser beam with an angle so that the rotation of the scanning head produces a conical scan. When measurements are performed at the focal point of the conical scan then three translational vibration components can be measured, otherwise the very small circle scan, before and after the focal point, can measure up to 6 degrees of freedom, including three translations and three rotations. This paper presents the 6DOF scanning head and the measurements of 3D operational deflection shapes of a test structure.

The robotized laser doppler vibrometer: On the use of an industrial robot arm to perform 3D full-field velocity measurements

“…Recently, automated solutions were developed in order to overcome these limitations. Using a set of mirrors assembled on a rotary hollow shaft, it has been shown that it is possible to measure the three translations and local rotations (6 DOFs) of a point by implementing continuous scanning along circular paths [14,15]. Perhaps the most complete solution can be found in [16], where three SLDVs are assembled on the head of an industrial robot arm.…”