Project Details
Projekt
Modular 3D-Scanning-Laser-Doppler-Vibrometer (Renewal)
Subject Area
Systems Engineering
Term
since 2026
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 584466286
As part of the extended application options for equipment renewal, an existing device—a modular, automated 3D scanning laser Doppler vibrometer (LDV) for small to medium-sized measurement objects—is to be upgraded and modernized. The upgrade will ensure the long-term usability of the device through targeted modernization of outdated modules and avoid the need for an expensive new purchase. A new purchase with comparable benefits (combination of three heterodyne 1D scanning vibrometers) would cost approximately eight times as much and would not offer the same technical benefits. The device to be modernized is a robot-assisted 3D scanning LDV, which enables three-dimensional measurement of vibrations through the use of three Helium-Neon (HeNe) laser heads, whereby focusing and adjustment of the cone angle and working distance are performed manually. The device is used by two research groups primarily for applications in the field of physiological and pathological hearing dynamics and related fundamental questions in the field of structural dynamics and system identification. Projects in the field of implantology of hearing aids and hearing implants as well as hearing diagnosis based on objective audiometric data are being worked on. A central component of these projects is the measurement of structural vibrations in the ear or in replacement models and the identification of suitable dynamic models to represent them. Two key limitations of the current configuration are apparent in these applications. Firstly, the HeNe laser heads used (wavelength 633 nm) are only suitable to a limited extent for highly scattering materials such as biomaterials or silicones. This makes it necessary to prepare the measurement objects with retroreflective foil or glass beads, which can distort the measurements and reduce measurement accuracy. Second, many of the measurement objects are very small and have measurement points that are difficult to access, which cannot or can only be reached with great effort with the existing setup. These limitations are being specifically addressed through modernization by replacing the HeNe laser heads with fiber-coupled infrared (IR) laser heads and replacing the mechanical setup with an automated mechano-optical setup. The IR laser heads (wavelength 1550 nm) enable up to tenfold increase in signal intensity. In addition, the penetration depth is increased and absorption is reduced, especially on biomaterials and plastics. This enables measurement of most objects without prior preparation. The new mechano-optical design enables automated focusing of the measuring point as well as adjustment of the working distance and cone angle. Together with the reduced installation space due to the small, fiber-coupled laser sources, accessibility to hard-to-reach measuring points is significantly improved.
DFG Programme
Major Research Instrumentation
Major Instrumentation
Modulares 3D-Scanning-Laser-Doppler-Vibrometer (Erneuerung)
Instrumentation Group
5750 Spezielle Laser-Mess-Systeme (z.B. Laser-Doppler-Vibrometer)
Applicant Institution
Hochschule Reutlingen
