Psychoacoustics and subjective assessment of variable-speed hydraulic drives

  Acoustic Measurement of a Pump

The electrification of industrial mechanical engineering is becoming increasingly widespread in both stationary and mobile applications. Especially in the field of mobile machines (excavators, wheel loaders, etc.), this leads to the hydraulic drive technology, which has so far been lost in the noise level of the combustion engine, becoming audible to the human ear and even perceptively coming to the fore. Pumps are the dominant noise source in hydraulic systems. They convert mechanical energy into hydraulic energy and can be found in almost all systems. The noise emission depends on the pump design and is still the subject of current research. However, only the noise level is considered, not the psychoacoustic parameters. The psychoacoustic classification of how people subjectively perceive and evaluate the noises emitted by different pump types - especially depending on speed and load - has not yet been researched. In addition, existing psychoacoustic models cannot be used to predict subjectively perceived annoyance, as they only allow product-specific statements. The acoustic and psychoacoustic properties of variable-speed hydraulic drives are investigated within the framework of the project.

 
Benefit Procedure

Consideration of the subjective hearing sensation of hydraulic drives with variable speed

Sound measurements (axial piston pump and internal gear pump) in the sound measurement room

Comparison of different pump designs (comparison of axial piston pump with an internal gear pump) regarding psychoacoustic parameters

Evaluation of sound measurements in terms of sound pressure levels and psychoacoustic parameters (loudness & sharpness)

Correlation regarding measured psychoacoustic quantities and the real subjective hearing sensation

Performing listening tests by the ifp

Model for the evaluation of subjective hearing sensation for hydraulic drives with variable speed Modelling of the subjective hearing sensation

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Psychoacoustics of pumps

The electrification of industrial mechanical engineering is becoming more and more common in both stationary and mobile applications. This leads, especially in the area of mobile machinery (excavators, wheel loaders, etc.), to the fact that the hydraulic drive technology, which up to now has been lost in the noise level of the combustion engine, is now audible to humans and may even come to the fore perceptively. The dominant noise source in hydraulic systems are pumps. They convert mechanical energy into hydraulic energy and can be found in almost all systems. The noise emission depends on the pump design and is still the subject of current research. However, only the noise level is considered, but not the psychoacoustic measurement variables. In this respect, the psychoacoustic classification of how people subjectively perceive and evaluate (e.g. in terms of annoyance) the noise emitted by different pump types - especially depending on speed and load - has not yet been researched. Furthermore, existing psychoacoustic models for predicting subjectively perceived annoyance cannot be adopted, as they only allow for product-specific statements. Within the project, the acoustic and psychoacoustic properties of hydraulic drives with variable speed are investigated.

Objective

In this project, the operating noise of variable-speed drives is investigated. For this purpose, the operating noises of an axial piston pump and an internal gear pump will be instrumentally recorded in sound measurements and the psychoacoustic parameters will be related to subjective perceptual judgements and noise evaluations from listening tests. To this end, the ifas works together with the Institute of Psychology (IfP) at the RWTH Aachen University.

 
 

Sound measurement of hydraulic drives with variable speed

Within the context of this project, an axial piston pump and an internal gear pump are being investigated. For this purpose, both pump types were measured in the sound measurement room and the instrumental noise level, loudness and sharpness were recorded. The essential operating parameters pressure and speed were varied in a targeted manner.

 

Acknowledgement

The research project is funded by the German Research Foundation. It is a joint project, which ifas is conducting together with the Institute of Psychology (IfP) with Univ.-Prof. Dr. Sabine Schlittmeier.