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

• Published in: Optics and lasers in engineering 2021-02, Vol.137, p.106363, Article 106363
• Main Authors: Margerit, Pierre, Gobin, Tristan, Lebée, Arthur, Caron, Jean-François
• Format: Article
• Language: English
• Subjects: Automatic; Engineering Sciences; Full-field measurements; Instrumentation and Detectors; Laser doppler vibrometer; Physics; Robotics
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/j.optlaseng.2020.106363

•using a programmable 6-axis industrial robot arm to perform measurements with improved positioning accuracy and automatization.•Achieving full-field velocity measurements with an affordable setup.•implementation of an open-source software dedicated to the proposed setup.•using a virtual twin of the experiment aiming to the design, the simulation and the control of the experiment.•comparison of the measurement data with numerical results. An original experimental setup, dedicated to the measurement of the dynamic response of structures, is presented. Called the Robotized Laser Doppler Vibrometer (RLDV), it consists in the assembly of a fixed point Laser Doppler Vibrometer (LDV) on a 6-axis industrial robot arm. This allows to measure the 3D velocity on the surface of objects with a wide range of shapes and sizes. In comparison with commercially available solutions, it represents an affordable and versatile tool. First, the motivations and the new challenges associated to the use of a robot arm to do such experiments are discussed. Second, the different strategies implemented to overcome these difficulties are developed. A software solution is proposed. By the use of a virtual model of the experimental setup, the measurement procedure can be designed and simulated in order to preview robot motion and avoid collisions. With a small number of parameters, the good proceeding of the measurement can be insured on a fine measurement mesh. The software is completed by an interface that allows for the setting of the signal acquisition parameters. At the end, all the procedure is automated and long measurements can be achieved with a reduced supervision. To illustrate the proposed setup, an experimental application is developed. The 3D modal shapes of a curved beam are measured and compared with numerical predictions, showing an excellent correlation.