Layer ToF Methods for Ultrasonic Lubrication-film Thickness Measurements

Kæseler, Rasmus Leck; Johansen, Nicolaj W.; Johansen, Per Michael

doi:10.1145/3284516.3284533

Cited by 3 publications

(11 citation statements)

References 17 publications

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“…The most commonly used ultrasound reflectometry methods for lubrication film thickness estimation are based on estimating the time-of-flight from the frequency response between the incident wave and the reflected waves. Such methods include the spring model [13], resonance [14], and layer phase-lag method [15]. Frequency response methods are often preferred over time-domain methods, such as the cross-correlation method [2], since time-domain methods are associated with excessive computing [16].…”

Section: Ultrasound Reflectometry For Lubrication Filmsmentioning

confidence: 99%

“…The methods above all have in common that they require an estimate of the incident wave. Notably, the resonance method can be used without calibration, but it is only applicable for relatively large lubrication films [1,15,17]. The apparent challenge is that the incident wave is not directly measurable when the system is ready for operation.…”

Section: The Calibration Problemmentioning

confidence: 99%

“…It is seen that the term within the sum of L(ω) has the property |R 1 R 2 J(ω)| < 1. This means that with the assumption that infinite reflections occur, the sum can be seen as a geometric series with the solution given by Equation ( 13) [15].…”

Section: The Acoustic Model Used For Adaptive Calibrationmentioning

confidence: 99%

“…With the property described by Equations ( 10) and (14), it is seen that the RCS can be described as Equation (15).…”

Section: The Acoustic Model Used For Adaptive Calibrationmentioning

confidence: 99%

“…This is what a study by Kaeseler and Johansen [19] addressed, where an extended-Kalman-filter (EKF)based observer was proposed to solve the regression model, instead of the curve fitting approach. Furthermore, this study also proposed a new regression model based on the LPL representation of the RCS, Equation (15), instead of the spring model. The regression model proposed by Kaeseler and Johansen [19] is based on the magnitude constraint of the LPL, given by Equation (25).…”

Section: Regression Model Approach To Adaptive Calibrationmentioning

confidence: 99%

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A Comparison of Adaptive Ultrasound Reflectometry Calibration Methods for Use in Lubrication Films

Hansen

Johansen

2022

Energies

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Adaptive calibration for ultrasound reflectometry methods used in the detection of lubrication film thickness is of great research interest. This is mainly due to the versatile non-destructive implementation of the technology in industrial applications, allowing for measurements of the lubrication film thickness, which directly relates to the friction, wear, and overall efficiency of the system. This study reviews and compares a curve fitting, extended Kalman filter, and resonance frequency detection adaptive calibration approach. Furthermore, the study compares two different regression models, used for the curve fitting and the extended Kalman filter approach. The study compares the methods and regression models based on both a theoretical and experimental analysis. The experimental analysis is based on data with varying lubrication film thickness. The lubrication film thickness is varied such that the resonance frequency is both detectable and non-detectable within the ultrasound transducer bandwidth. It is found that all three methods give results very similar to those achieved through manual calibration. However, since the extended Kalman filter approach is the only method that allows for continuous calibration, this method is found to have the greatest potential of the methods compared.

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Section: Ultrasound Reflectometry For Lubrication Filmsmentioning

confidence: 99%

Section: The Calibration Problemmentioning

confidence: 99%

Section: The Acoustic Model Used For Adaptive Calibrationmentioning

confidence: 99%

“…With the property described by Equations ( 10) and (14), it is seen that the RCS can be described as Equation (15).…”

Section: The Acoustic Model Used For Adaptive Calibrationmentioning

confidence: 99%

Section: Regression Model Approach To Adaptive Calibrationmentioning

confidence: 99%

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A Comparison of Adaptive Ultrasound Reflectometry Calibration Methods for Use in Lubrication Films

Hansen

Johansen

2022

Energies

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An accurate measurement method for center oil film thickness in high-speed roller bearing using ultrasound

Wang,

Li,

Bao

et al. 2024

Tribology International

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Adaptive ultrasound reflectometry for lubrication film thickness measurements

Kæseler

Johansen

2019

Meas. Sci. Technol.

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Adaptive ultrasound reflectometry methods for lubrication film thickness measurements is of great use for condition monitoring and prognostics of systems which have high repair costs and are remotely located, such as off-shore systems, as they recursively calibrate the incident ultrasound wave. Typical manual calibration requires a constant incident wave over the life-cycle of the system, or until new manual calibration can be conducted. Auto-calibration accounts for the changes in the incident ultrasound wave caused by changing environmental conditions, occurring over longer periods of time. The vision of adaptive ultrasound reflectometry methods is therefore increased robustness of lubrication film thickness measurements in a range of applications. In this article an adaptive scheme is proposed. The scheme is based on a thin-layer time-of-flight method for thickness determination, and an extended Kalman filter for estimation of the incident wave spectrum. The adaptive scheme is experimentally tested, and the feasibility of the algorithm is established, but serious issues regarding the robustness and reliability of the method are revealed by a disturbance analysis. However, the experiments and a theoretical layer phase-lag sensitivity analysis reveal that the estimation of the incident wave phase is of high importance for layer thicknesses above m, and for very thin layers below m the estimation of the magnitude dominates the measurement accuracy. This entails that the research in adaptive schemes should be directed towards phase- or magnitude-tracking performance, depending on the working range of the layer thickness, such that sufficient robustness and reliability of the algorithms can be assured.

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Layer ToF Methods for Ultrasonic Lubrication-film Thickness Measurements

Cited by 3 publications

References 17 publications

A Comparison of Adaptive Ultrasound Reflectometry Calibration Methods for Use in Lubrication Films

A Comparison of Adaptive Ultrasound Reflectometry Calibration Methods for Use in Lubrication Films

An accurate measurement method for center oil film thickness in high-speed roller bearing using ultrasound

Adaptive ultrasound reflectometry for lubrication film thickness measurements

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