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Improved set-up for the dynamic characterization of multi-component sensors for force and moment

06.11.2018

To calibrate a sensor for force or moment, the sensor is loaded with a force or a moment of a known amplitude and the sensor signal is compared to this known load. Newton’s second law of motion is typically used to calculate a reference force. In this law, a force is described as the product of a known mass with a known acceleration. For the moment component, an additional lever arm between the force and the sensor is needed.

The electrodynamic shaker set-up used at PTB is capable of generating time variable accelerations in one axis. This acceleration is measured in the same axis using a laser vibrometer. By mounting a force sensor connected to a known load mass on top of the shaker, the force acting on the sensor can be calculated from the reference acceleration and the load mass.

For the characterization of multi-component sensors, it is necessary to change the direction of the reference force or the moment acting on the sensor. At the same time, the identification of the acceleration of the load mass in different directions is important. These two topics were investigated in a joint research project of PTB and the Institute of Production Metrology (IPROM) of the TU Braunschweig, funded by the Deutsche Forschungsgemeinschaft (DFG). For the excitation in different directions, mounting adapters were designed which allow the mounting of a sensor in different orientations on top of the shaker armature. This allows the excitation of force and moment components in the three axes of the sensor.

An additional photogrammetric measurement set-up, consisting of two stereo camera systems, was installed in the set-up. One camera system observes the load mass on top of the sensor and is able to identify the motion of the load mass with six degrees of freedom. The acceleration in the different directions can be calculated from the time-dependent displacement of the load mass. This allows the identification of the reference force and the moment components acting on the sensor. Figure 1 shows a photograph of a multi-component sensor mounted on the shaker armature. The cameras of the photogrammetry system can be seen in the background.

The first experiments were performed using a commercially available sensor. The development and the results of the first experiment are described in detail in an article, which has been accepted for publication in the Journal of Sensors and Sensor Systems [1].

Figure 1: Multi-component sensor mounted on the electrodynamic shaker. Cameras of the photogrammetric measurement system can be seen in the background. [1]

Literature:

[1] J. Nitsche, R. Kumme, R. Tutsch: Dynamic characterization of multi-component sensors for force and moment, Journal of Sensors and Sensor Systems, 7, 577–586, 2018, Opens external link in new windowLink

Contact:

Jan Nitsche, FB 1.2, AG 1.21, E-Mail: Opens window for sending emailjan.nitsche(at)ptb.de