This file was created by the TYPO3 extension bib --- Timezone: CEST Creation date: 2024-04-25 Creation time: 03-32-06 --- Number of references 100 incollection brunsTraceableCalibrationDynamic2023 2023 73--98 https://www.degruyter.com/document/doi/10.1515/9783110713107-003/html 2023-12-12 Eichstädt, Sascha De Gruyter Dynamic Measuring Systems 978-3-11-071310-7 10.1515/9783110713107-003 ThomasBruns LeonardKlaus MichaelKobusch inproceedings klausChallengesLowFrequency2023 2023 The traceable calibration of seismometers is research work within the European research project InfraAUV, which is part of the EMPIR programme. In this project, novel in-laboratory and on-site calibration procedures for seismometers are developed. The in-laboratory calibrations are carried out using electrodynamic shakers to excite sinusoidal vibrations. These excitations are measured by the seismometer under test and a reference laser interferometer. https://doi.org/10.5194/egusphere-egu23-13404

Wien

LeonardKlaus FranckLarsonnier JacobWinther ThomasBruns inproceedings klausTraceableCalibrationSeismometers2023 2023 At present, seismometers are not traceably calibrated. This means that their output sensitivity is not determined in a way that is traceable to the International Systems of Units (SI). The European research project 19ENV03 Infra-AUV, which is part of the EMPIR programme, develops methods and procedures to enable such traceable calibrations. In contrast to many other sensors, seismometers are operated stationary in their typical measurement application, i.e., they must not be moved after their deployment. Conventional calibration approaches which involve a laboratory calibration of the seismometer to be calibrated are therefore not feasible. For this reason, a new concept currently developed by different European partners within the Infra-AUV project proposes an on-site calibration scheme. For the on-site calibration, a reference seismometer is traceably calibrated to the SI in a laboratory. This reference is then used on-site to provide a secondary calibration of other seismometers, e.g. in a seismic station, using natural excitation sources [Schwardt et al., 2022, DOI: 10.1007/s10712-022-09713-4]. The calibration of reference seismometers in the laboratory is carried out as a primary calibration. This means that the measured quantity (the velocity-proportional voltage output) is compared to a different quantity, in this case to a dynamic displacement measurement traced back to the units length and time, which can be measured very precisely by laser interferometry. In this calibration, the seismometer is excited with low-frequency mechanical vibrations generated by electrodynamic exciters. These calibrations must be performed for the horizontal and vertical axes. The frequency range of interest is from 20 Hz down to 0.01 Hz, depending on the seismometer under test. Either mono-frequency sinusoidal excitations of different frequencies are applied subsequently, or multiple frequencies are excited simultaneously using a multi-sine approach. The magnitudes and phases of both measured signals, the interferometric reference and the seismometer under test, are determined by using sine approximation algorithms or by applying a discrete Fourier transform (DFT). The results of the laboratory calibration, the transfer function of the reference seismometer, can then be derived from the ratios of the measured magnitudes and the differences of the phase angles for the different excitation frequencies. In addition, the associated measurement uncertainties are estimated and are part of the calibration result. Influences that may change the sensitivity of a seismometer, e.g., temperature effects, electromagnetic sensitivity, or ground stiffness need to be analysed and additionally taken into account for the uncertainty estimation. For the uncertainty of the on-site calibration, differences between the laboratory and the on-site environment also need to be taken into account. This includes, for example, aspects like typically different temperatures or different ground materials. https://dx.doi.org/10.5194/egusphere-egu23-13404

Wien

LeonardKlaus FranckLarsonnier JacobWinther MichaelaSchwardt MichaelKobusch ThomasBruns inproceedings schwardtDeterminationFrequencyResponse2023 2023 As part of the joint research project "Metrology for low-frequency sound and vibration - 19ENV03 Infra-AUV" laboratory calibration methods for seismometers and microbarometers in the low frequency range down to 0.01 Hz have been developed. These procedures provide the possibility of traceable on-site calibration during operation for field sensors of the Comprehensive Nuclear-Test-Ban Treaty Organization’s (CTBTO) International Monitoring System (IMS). The traceable calibration allows for accurate amplitude and phase information as well as for an assignment of uncertainties in amplitude and phase. Thereby, data quality and the identification of treaty-relevant events is improved. The on-site calibration procedure requires a reference sensor with a precise and traceable response function which is provided by the newly developed laboratory calibration methods, as well as the record of sufficient coherent excitation signals within the relevant frequency range. The reference sensors can be installed as transfer standards co-located to the operational IMS station sensors without disturbing their regular measurements for treaty validation purposes. At IMS stations PS19 and IS26 in Germany we performed on-site calibration tests with both seismometers and microbarometers calibrated in the laboratories at PTB and CEA, respectively, using signals from different natural and anthropogenic excitation sources. Following the approach of Gabrielson (2011) with modifications from Charbit et al. (2015) and Green et al. (2021), the gain ratio between the station sensor under test and the reference sensor is calculated. By multiplying the gain ratio with the precise frequency response of the reference, the frequency response function for both magnitude and phase of the station sensors including site-specific factors such as the wind noise reduction system or possible effects of pre-amplifiers and data loggers are determined. We present calibration results derived from the comparison of IMS station sensors with the laboratory-calibrated instruments along with the nominal responses. The results show agreement with deviations of less than 5% from the nominal response function for frequencies below 10 Hz for all components. The traceable determination of the response for the individual components in detail improves the sensor quality; subsequently waveform amplitudes can be estimated correctly. https://doi.org/10.5194/egusphere-egu23-11059

Wien

MichaelaSchwardt ChristophPilger SamuelKristoffersen FranckLarsonnier LeonardKlaus ThomasBruns LarsCeranna misc brunsPrimaryCalibrationSeismometers2023 2023 The presentation explains the process of primary calibration of motion sensors by laser interferometry with the example of seismometers. by looking at the involved units of voltage, time and length, it focuses on the methods used to confirm the traceability to the SI.

Wien

ThomasBruns misc brunsTraceabilitySIWhat2023 2023 The presentation explains the process of operation of the international system of Units to the geoscience community. It addressed the role and position of national metrology institutes on a national and international scale, as well as the tool of key comparisons for international harmonisation. Finally it advertises the benefits of linking measurements to national standards under the umbrella of the CIPM-MRA.

Wien

ThomasBruns misc brunsDeterminationFrequencyResponse2023 2023 The development of laboratory calibration methods for seismometers and microbarometers in the low frequency range down to 0.01 Hz provides the possibility of a traceable on-site calibration during operation for field sensors of the International Monitoring System. The laboratory calibrated reference sensors can be installed as transfer standards at the stations co-located to the operational sensor, thereby improving data quality and identification of Treaty-relevant events while not disturbing the regular measurements for Treaty validation purposes. At International Monitoring System stations PS19 and IS26 in Germany we performed on-site calibrations tests with both seismometers and microbarometers calibrated at the laboratories at PTB and CEA, respectively, using signals from different natural and anthropogenic excitation sources. Following the approaches of Gabrielson (2011) and Green et al. (2021), the frequency response function of the station sensors including site specific factors such as the wind noise reduction system or possible effects of pre-amplifiers and data loggers are determined. We present calibration results of the comparison between the station sensors with the laboratory-calibrated instruments along with the nominal responses of the sensors. Furthermore, the possibility of a station-wide calibration of seismometers with a single temporary and stationary reference sensor is assessed using suitable excitation signals and station-wide similarity measures.

Wien

ThomasBruns MichaelaSchwardt ChristophPilger LeonardKlaus SamuelKristoffersen FranckLarsonnier LarsCeranna PatrickHupe PeterGaebler article klaus20DynamicTorque2022 Measurement: Sensors 2022 22 100370 Research in the field of dynamic torque calibration has gained some momentum in the last few years. At PTB, a calibration device for small dynamic torque levels up to about 0.5 N⋅m proved the working principle of dynamic torque calibrations with sinusoidal excitation. In a next step, a new calibration device was developed with the intention of generating higher dynamic torque levels in the range of up to 20 N⋅m. Although this is still less than many industrial applications require, it could pave the way to higher torque levels. The new calibration device features a horizontal arrangement of all components of the drive shaft. The device consists mostly of industrial components that have been modified, rather than custom-made components. After commissioning, optimising the device enabled a frequency range from 10 Hz to up to 400 Hz with dynamic torque amplitudes of up to 20 N⋅m. https://linkinghub.elsevier.com/retrieve/pii/S2665917422000046 2024-04-10 26659174 10.1016/j.measen.2022.100370 LeonardKlaus MichaelKobusch article rosenkranzFinalReportSupplementary2022 Metrologia 2022 59 1A 09001 The Supplementary comparison EURAMET.AUV.V-S1 has been carried out within the framework of the CIPM MRA. The specific task of this comparison is the measurement of the magnitude and phase of the sensitivity of single-ended accelerometers in the medium frequency domain (10 to 10 000 Hz). The sensitivity is calculated as the ratio of the amplitude of the output of the accelerometer to the amplitude of the acceleration at its reference surface with secondary means in accordance with ISO 16063-21 "Methods for the calibration of vibration and shock transducers - Part 21: Vibration calibration by comparison to a reference transducer". The participating NMIs are BEV (Austria), BIM (Bulgaria), CMI (Czech Republic), IPQ (Portugal), KEBS (Kenya), METAS (Switzerland) and MIKES (Finland). BEV (Austria) was the pilot laboratory of the comparison. The measurements took place between October 2019 and February 2021. Three single-ended accelerometers were circulated. The final report includes the measurement results from the participants, information about their calibration methods, and the analysis leading to the assignation of equivalence degrees. https://iopscience.iop.org/article/10.1088/0026-1394/59/1A/09001 2022-06-01 0026-1394, 1681-7575 10.1088/0026-1394/59/1A/09001 PeterRosenkranz DanielaVirovska MilanPrasil Luis FilipeRibeiro Anderson KMaina ChristianHof JussiHämäläinen ThomasBruns EnverSadikoglu article seegerComparisonDynamicPrimary2022 Metrologia 2022 59 3 035002 In the framework of the EU-funded project Met4FoF Metrology for the Factory of the Future a method was developed to perform primary magnitude and phase calibration of accelerometers. The validation of the developed associated hard- and software, which is designed to complement conventional primary calibration systems, is demonstrated based on a comparison measurement between the project partners CEM and PTB. The results show that the statistical distribution of results is only a minor contribution to uncertainty. An evaluation of the comparison based on the conventional procedure and established CMCs proofed a good consistency between the two laboratories, although the utilized sensor was (only) industrial grade quality. https://iopscience.iop.org/article/10.1088/1681-7575/ac5a5d 2022-06-01 0026-1394, 1681-7575 10.1088/1681-7575/ac5a5d BenediktSeeger EhlimanaJugo AlenBosnjakovic SalustianoRuiz ThomasBruns inproceedings seegerAbsoluteTimebasedDynamic2022 2022 This paper describes an absolute time-based concept to simultaneously calibrate a large number of MEMS sensors using Ethernet as communication interface and investigates new uncertainty influences related to the absolute time base.

Dubrovnik

IMEKO International Conference 10.21014/tc22-2022.054 BenediktSeeger ThomasBruns inproceedings volkersUsingCommonlyAvailable2022 2022 We have demonstrated that commonly available small form-factor pluggable (SFP) modules can be used for LDV excitation and calibration. While the expected intensity modulation at the photodiode inside the LDV interferometer is sinusoidal, the SFP module output is designed for and provides a rectangular modulation shape. The conducted experiments produced comparable results.

Dubrovnik

IMEKO International Conference 10.21014/tc22-2022.067 HenrikVolkers BenediktSeeger inproceedings yanLowFrequencyPrimary2022 2022 The multi-component vibration calibration device at PTB consists of a triaxial shaker which is suitable and convenient for calibrating multi-axial seismometers. Three laser vibrometers are furthermore utilised as references. The frequency range was further extended for a European research project. Instead of a closed-loop control system limiting the vibration frequency down to 0.4 Hz, a signal generator is now used to provide the excitation voltage to the amplifier of the shaker in open-loop mode. This excites the shaker yielding vibrations with significantly lower frequencies. The first test measurements with a seismometer were carried out. The results demonstrate that a calibration down to 10 mHz is easily achievable.

Dubrovnik

IMEKO International Conference 10.21014/tc22-2022.019 NaYan LeonardKlaus ThomasBruns article brunsDemonstratorMeasurementWorkflows2021 Measurement: Sensors 2021 18 100208 Based on the existing specifications for digital calibration certificates (DCCs), this work presents two approaches to using DCCs in a fully digitised workflow. It shows the basic methods needed to access, edit and deposit DCCs in either a web repository or a file system. These methods are introduced to the reader in examples using Excel macros based on Visual Basic for Applications (VBA) or the Python 3 programming language, meaning that they can be used immediately. https://linkinghub.elsevier.com/retrieve/pii/S2665917421001719 2021-10-14 26659174 10.1016/j.measen.2021.100208 ThomasBruns JanNordholz DirkRöske ThorstenSchrader article brunsEfficientVeryLow2021 Measurement: Sensors 2021 18 100156 This article describes an extension to the usual primary calibration of accelerometers according to ISO 16063 which tackles the problem of extremely long measuring times for low frequency excitation. The method utilizes a superposition of sine-signals at discrete frequencies in order to determine the complex frequency response for several frequencies in a single run. The article describes the synthesis of the excitation signal taking care of the detection of potential harmonic distortion. It explains the process of data analysis extending the well-known sine-approximation to simultaneous multi-frequency fitting including a period-wise slicing of the data. Finally, some examples of real measurements are provided. https://linkinghub.elsevier.com/retrieve/pii/S2665917421001197 2021-10-14 26659174 10.1016/j.measen.2021.100156 ThomasBruns article eichstadtSmartTraceabilityDigital2021 Sensors 2021 21 6 2019 The Internet of Things (IoT) is characterized by a large number of interconnected devices or assets. Measurement instruments in the IoT are typically digital in the sense that their indications are available only as digital output. Moreover, a growing number of IoT sensors contain a built-in pre-processing system, e.g., for compensating unwanted effects. This paper considers the application of metrological principles to such so-called “smart sensors” in the IoT. It addresses the calibration of digital sensors, mathematical and semantic approaches, the communication of data quality and the meaning of traceability for the IoT in general. https://www.mdpi.com/1424-8220/21/6/2019 2021-08-24 1424-8220 10.3390/s21062019 SaschaEichstädt MaximilianGruber Anupam PrasadVedurmudi BenediktSeeger ThomasBruns GertjanKok article klausNewDynamicTorque2021 Measurement: Sensors 2021 18 100149 Research in the field of dynamic torque calibration has gained some momentum in the last few years. At PTB, a calibration device for small dynamic torque levels up to about 0.5 N m proved the working principle of dynamic torque calibrations with sinusoidal excitation. In a next step, a new calibration device was developed with the intention of generating higher dynamic torque levels in the range of up to 20 N m. Although this is still less than many industrial applications require, it could pave the way to higher torque levels. The new calibration device features a horizontal arrangement of all components of the drive shaft. The device consists mostly of industrial components that have been modified, rather than custom-made components. After commissioning, optimising the device enabled a frequency range from 10 Hz to up to 400 Hz. https://linkinghub.elsevier.com/retrieve/pii/S2665917421001124 2021-10-14 26659174 10.1016/j.measen.2021.100149 LeonardKlaus MichaelKobusch inproceedings seegerD1DynamicCalibration2021 2021 320--320 For the processing of dynamic data (e.g. vibrations) an exact knowledge of the temporal relations is necessary. In this topic we present a GPS based method for time stamping of dynamic signals. As well as dynamic calibration methods based on this data for sensors with exclusively digital output. https://www.ama-science.org/doi/10.5162/SMSI2021/D1.4 2021-10-14 AMA Service GmbH, Von-Münchhausen-Str. 49, 31515 Wunstorf, Germany

digital

SMSI 2021 - System of Units and Metreological Infrastructure 10.5162/SMSI2021/D1.4 BenediktSeeger ThomasBruns misc cerannaInfraAUVProjectMetrology2021 2021 Infra-AUV is a new EU project that will establish primary measurements standards for low frequency phenomena across the fields of airborne and underwater acoustics and vibration (seismology). Combining expertise from the national measurement institutes and geophysical monitoring station operators, it will develop both high-precision laboratory-based methods of calibration and methods suitable for field use. Infra-AUV will also address requirements for reference sensors that link laboratory calibration capabilities to field requirements for measurement traceability. To establish standards in the three technical areas, a variety of calibration principles will be employed, including extension of existing techniques such as reciprocity and optical interferometry, and development of new methods. There will also be an investigation of the potential for in-situ calibration methods, including use of both artificially generated and naturally occurring stimuli such as microseisms and microbaroms. The influence of calibration uncertainties on the determination of the measurands required by the monitoring networks will also be studied. The project was strongly motivated by the CTBTO strategy to drive new metrology capability to underpin IMS data. The intention is to maintain interaction with stakeholders, not only in connection with the IMS, but with the broad range of users of low frequency acoustic and vibration data. https://meetingorganizer.copernicus.org/EGU21/EGU21-16476.html 2023-06-30

Vienna, Austria

10.5194/egusphere-egu21-16476 LarsCeranna ThomasBruns ChristianKoch DominiqueRodrigues StephenRobinson Jacob HolmWinther FranckLarsonnier RichardBarham article daiNovelMaterialMeasure2020 Surface Topography: Metrology and Properties 2020 8 4 045025 A new material measure for characterising two-dimensional (2D) instrument transfer functions (ITF) of areal surface topography measuring instruments has been designed, manufactured, calibrated and applied. Several innovative ideas are implemented in its design. Firstly, the material measure is designed with circular structure patterns. Such rotational symmetric patterns are advantageous for characterising the ITF in different angular directions, thus for characterising angular-dependent asymmetries of instruments. Secondly, different types of patterns are designed: circular chirp (CC) pattern and circular discreate grating (CDG) pattern. They represent different kinds of spatial signals applicable for characterising ITFs. A material measure consists of 25 different circular patterns with radii from 30 μm to 300 μm, and wavelengths from 0.1 μm to 150 μm. These patterns can be applied complementary and combinedly, offering high application flexibility for calibrating a variety of instruments, e.g. with different optical objectives from 5× to 100× and with different sizes of field of view (FOV). Material measures with heights of 8 nm, 16 nm and 32 nm, respectively, have been manufactured using state-of-the-art e-beam lithography technique. The feature heights are far less than λ/4, thus they are suitable for characterising the ITF of optical tools which can be approximated as linear systems. A metrological large range atomic force microscope (AFM) has been applied in the calibration of the developed material measure, showing good feature quality. The calibrated material measure has been successfully applied in research and industry. https://iopscience.iop.org/article/10.1088/2051-672X/abc9d2 2021-02-25 2051-672X 10.1088/2051-672X/abc9d2 GaoliangDai ZiyangJiao LantingXiang BenediktSeeger ThomasWeimann WeichangXie RainerTutsch article klausleonardStaticDynamicBridge2020 ACTA IMEKO 2020 9 5 200 Dynamic measurements to correctly adjust the magnitude in fatigue testing require a dynamic calibration of force transducers and conditioning electronics if the dynamic loads are to be measured correctly. International standard ISO 4965 describes a calibration method for these components. At PTB, such a calibration of bridge amplifiers has now been performed for the first time. The calibration includes tests with static and dynamic signals. The reference for the calibration is the dynamic bridge standard of PTB. It is particularly suitable for this application as it can generate static and dynamic signals, and thus all investigations can be performed with one reference and in a reasonably short time. The signal creation and the data analysis were carried out using the open source program GNU Octave. For the data analysis, a semi-automatic procedure was developed to simplify the process. Calibrations of two digital bridge amplifiers were carried out. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-09%20%282020%29-05-42 2021-02-20 2221-870X 10.21014/acta_imeko.v9i5.969 Leonard</prt><prt>Klaus article kobuschmichaelInsituDynamicForce2020 ACTA IMEKO 2020 9 5 118 This paper presents experimental investigations of in-situ dynamic force calibrations in which an impact hammer provides the dynamic reference force. Here, the force transducer to be calibrated remains in the original mechanical structure of the force measurement application to which calibration shock forces are applied in a suitable way. Numerous experiments with different force transducer set-ups and different impact hammer configurations were conducted to validate this in- situ calibration method. The paper describes the analysis of the measurement data and presents the force transfer functions obtained. Finally, these dynamic calibration results are discussed. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-09%20%282020%29-05-26 2021-02-20 2221-870X 10.21014/acta_imeko.v9i5.952 Michael</prt><prt>Kobusch Leonard</prt><prt>Klaus article seegerbenediktDynamicCalibrationDigital2020 ACTA IMEKO 2020 9 5 394 MEMS gyroscopes/angular rate sensors are often equipped with a digital output only. As part of a European research project, the dynamic calibration of sensors with digital output is being investigated. In the following, the operation principle of digital gyroscopes is described, a possible way to derive correct timestamped data from those sensors using a digital acquisition unit is explained and a calibration procedure is presented. The calibration of the analogue input of the digital acquisition unit, which is a prerequisite to derive correct phase responses, is described. Measurements with digital sensors proved the working principles and gave insight into the dynamic behaviour of those gyroscopes. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-09%20%282020%29-05-81 2021-02-20 2221-870X 10.21014/acta_imeko.v9i5.1008 Benedikt</prt><prt>Seeger Leonard</prt><prt>Klaus Denis</prt><prt>Nordmann article volkershenrikLaserDopplerVibrometerCalibrationLaser2020 ACTA IMEKO 2020 9 5 357 A new set-up for primary laser vibrometer calibration was developed and tested at the acceleration laboratory of PTB. Contrary to existing set-ups, this configuration makes use of electro-optical excitation.While avoiding the limitations imposed by mechanical motion generators in classic set-ups, the new method still encompasses all components of commercial laser vibrometers in the calibration and thus goes beyond the current capabilities of the purely electrical excitation schemes. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-09%20%282020%29-05-73 2021-02-20 2221-870X 10.21014/acta_imeko.v9i5.1000 Henrik</prt><prt>Volkers Thomas</prt><prt>Bruns article volkershenrikPrimaryShockCalibration2020 ACTA IMEKO 2020 9 5 383 This paper describes the implementation of a new, fast and precise linear motor drive for PTB’s primary shock calibration device. This device is used for monopole shock calibrations of accelerometers using the “hammer-anvil” principle according to ISO 16063-13:2001 and operates in a peak acceleration range from 50 m/s² to 5000 m/s². The main challenge of implementing this kind of shock generator is accelerating a hammer to velocities up to 5 m/s within distances of less than 70 mm. In this paper, a few helpful improvements are described which lead to an enhanced repeatability of pulse generation over the full shock intensity range as well as a substantial decrease of harmonic disturbing signals. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-09%20%282020%29-05-79 2021-02-20 2221-870X 10.21014/acta_imeko.v9i5.1006 Henrik</prt><prt>Volkers Holger C.</prt><prt>Schoenekess Thomas</prt><prt>Bruns book volkersZurStosskalibrierungBeschleunigungssensoren2020 2020 Die vorliegende Arbeit beschreibt die Untersuchungen und die Entwicklung von Verfahren und Anregungsformen zur Parameteridentifikation eines Modells für Beschleunigungssensoren mit dem Ziel einer besseren Vergleichbarkeit von Stoßkalibrierungen von Beschleunigungssensoren bei Stoßamplituden größer 5 km/s². Die modellbasierte Rekonstruktion des Anregungssignals über ein 2-DOF-Modell ermöglicht es erstmals Stoßvergleichskalibrierungen unabhängig von der Stoßform und mit hoher Genauigkeit durchzuführen. Bedingt durch die Abhängigkeit des Spitzenwertverhältnisses von der spektralen Zusammensetzung der anregenden Pulsform waren in der Vergangenheit die Vergleiche von Übertragungsfaktoren zwischen unterschiedlichen Stoßeinrichtungen mit zunehmender Stoßintensität mit zunehmenden Unsicherheiten behaftet. Das vorgestellte Verfahren reduziert diese Unsicherheiten deutlich, weitestgehend unabhängig von der spektralen Zusammensetzung des Stoßes. Weiterhin erfolgte eine systematische Betrachtung aller relevanten Einflussgrößen zur Stoßkalibrierung von Beschleunigungssensoren und die Einführung neuer Mess- und Auswertungsverfahren, insbesondere für die korrekte Kalibrierung von Ladungsverstärkern, die systematische Abweichungen der Vergangenheit vermeidet. https://doi.org/10.2370/9783844076578 2021-08-24 Shaker Verlag GmbH

DE

1 HenrikVolkers article klausSetupDynamicCalibration2019 ACTA IMEKO 2019 8 1 19 Measurements of mechanical quantities are often carried out with transducers with a bridge output. The output signals are conditioned using bridge amplifiers. If dynamically changing quantities are going to be measured traceably, the bridge amplifier must be calibrated dynamically. This paper describes a dynamic bridge amplifier calibration setup based on the new PTB dynamic bridge standard. The calibration is carried out by the synchronous sampling of the bridge amplifier output voltage and a reference signal provided by the calibrated dynamic bridge standard. The dynamic bridge standard enables calibrations in a frequency range from DC (static calibration) up to 10 kHz. An overview of the different measurement uncertainty contributions is given, and the first measurement results show good agreement with a previously established measurement setup. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-08%20%282019%29-01-04 2019-04-02 2221-870X 10.21014/acta_imeko.v8i1.657 LeonardKlaus M. FlorianBeug ThomasBruns article volkersTwoDOFModelbasedInput2019 Measurement Science and Technology 2019 30 5 055001 This article describes a two-degree-of-freedom (two-DOF) model-based input prediction method in the frequency domain for the comparison of high-shock acceleration calibration facilities. The current measurand for transferring the unit is the shock sensitivity as the relationship between the peak values of the accelerometer output quantity and the acceleration. The common transfer standards applied in shock calibration facilities in the range up to 100 km s−2 are piezoelectric-based transducers with a first resonance close to, or within, the spectrum of the exciting shock. This leads to the effect that the provided is, technically speaking, only valid for shocks of the same spectral composition, resulting in unpleasantly high uncertainties in high-shock measurements. This is thus not feasible if applied to shocks of differing spectral composition. A parametrized two-DOF model is capable of describing the transfer standard and allows the prediction of the applied input excitation with unprecedented accuracy. A method for the parameter identification and input prediction in the frequency domain and the results for two transfer standards are presented. http://stacks.iop.org/0957-0233/30/i=5/a=055001?key=crossref.bae78a624ed17baa6d4b483c70facd89 2019-11-14 0957-0233, 1361-6501 10.1088/1361-6501/ab0a2f HenrikVolkers ThomasBruns Georg-PeterOstermeyer inproceedings larsonnierComparisonSeismometerSensitivity2019 2019 27003 Accelerometer calibration by primary and secondary means is now very well covered both in low and medium frequency range. This is obviously not the case for seismometers which are widely used in the world. Up to now, seismometers only have internal checks thanks to an integrated coil. Calibration of these devices address different challenges like large mass and volumes, non-rotatable devices, specific mounting. This inter laboratory comparison will help to investigate these fields and to give feedback to develop a methodology to calibrate seismometers. https://cfmetrologie.edpsciences.org/10.1051/metrology/201927003 2019-11-14 Gazal, Sandrine EDP Sciences

Paris, France

19th International Congress of Metrology (CIM2019) 978-2-7598-9069-9 10.1051/metrology/201927003 FranckLarsonnier GuillaumeRouillé ClaireBartoli LeonardKlaus PhilippBegoff inproceedings seegerMethodsDynamicCalibration2019 2019 22003 We present a method for data acquisition and calibration of digital accelerometers which is being developed within the EMPIR Met4FoF project based on STM32 microcontrollers. Unlike analog sensors, some MEMS sensors with digital interface generate the sample clock themselves. For a dynamic calibration the exact knowledge of the sample times is essential. Therefore, an interrupt controlled data acquisition based on hardware timers with absolute time stamping was implemented. These routines are generic and can be used both for sensors that perform the measurements automatically, or for sensors whose data acquisition is requested by a hardware or software interrupt. The synchronization of the hardware timer with the absolute time is done via GNS time services or another PPS time source. The data is transferred from the microcontroller via ethernet to a host PC, which is to provide an OPC-UA interface and thus enables simple integration of the sensor system into larger measuring systems, like existing calibration setups. In addition to the acquisition of raw data for sensor calibrations, the system consisting of microcontroller and driver on the host system is also intended to provide dynamic measurement uncertainties. In addition, information about the calibration and the status of the sensor should be available on the system. The calibration data should be stored inform of a signed xml file on the microcontroller. In addition to this static information, the system should also record dynamic information about the status of the sensor, such as operating time, exceeding of measuring ranges, min and max temperature during operation. https://cfmetrologie.edpsciences.org/10.1051/metrology/201922003 2019-11-14 EDP Sciences

Paris, France

19th International Congress of Metrology (CIM2019) 978-2-7598-9069-9 10.1051/metrology/201922003 BenediktSeeger ThomasBruns SaschaEichstädt article brunsEfficientCalibrationModelling2018 Journal of Physics: Conference Series 2018 1065 222005 Charge amplifier calibration at low frequencies is a time-consuming service. This paper presents a method to speed up the process by measuring decades of frequencies in a single run. Based on the calibration results gained, a filter design process is introduced that facilitates a multi-rate approach to digital IIR filters in order to circumvent the complications arising from high-pass filtering with low corner frequency at high sampling rates. http://stacks.iop.org/1742-6596/1065/i=22/a=222005?key=crossref.aea4d19370474d0c773269c164add15a 2018-11-20 1742-6588, 1742-6596 10.1088/1742-6596/1065/22/222005 ThomasBruns HenrikVolkers article brunsSmartSensorConcept2018 Journal of Physics: Conference Series 2018 1065 212011 Smart sensors are the metrological challenge of the current trend towards digitization and "Internet of Things" (IoT). In particular for use in dynamic measurement applications, these cross-linked devices could help to provide more accurate and reliable data for the user while at the same time relieving the burden of complex signal processing. This paper presents a concept for a smart sensor in metrological terms. It is a forecast of the development that is to be implemented in an approved joint European research project which is about to start in the summer of 2018. http://stacks.iop.org/1742-6596/1065/i=21/a=212011?key=crossref.563604c077a8ea328b3fc66e6a00e6e7 2018-11-20 1742-6588, 1742-6596 10.1088/1742-6596/1065/21/212011 ThomasBruns SaschaEichstädt article volkersMethodHighshockAccelerometer2018 Journal of Physics: Conference Series 2018 1065 222013 By applying a parameterized 2-DOF model to an Endevco type 2270 B2B sensor for the transfer of the unit shock sensitivity SSh, the drawback of the systematic spectral influence to SSh of shock exciters with different spectral composition can be compensated in the frequency domain. The method and first results are presented. http://stacks.iop.org/1742-6596/1065/i=22/a=222013?key=crossref.d2ba4e23690153146f9c45990d17c3d5 2018-11-20 1742-6588, 1742-6596 10.1088/1742-6596/1065/22/222013 HenrikVolkers ThomasBruns article klausMonteCarlobasedUncertaintyPropagation2018 Metrologia 2018 55 2 S70-S85 For a dynamic calibration, a torque transducer is described by a mechanical model, and the corresponding model parameters are to be identified from measurement data. A measuring device for the primary calibration of dynamic torque, and a corresponding model-based calibration approach, have recently been developed at PTB. The complete mechanical model of the calibration set-up is very complex, and involves several calibration steps—making a straightforward implementation of a Monte Carlo uncertainty evaluation tedious. With this in mind, we here propose to separate the complete model into sub-models, with each sub-model being treated with individual experiments and analysis. The uncertainty evaluation for the overall model then has to combine the information from the sub-models in line with Supplement 2 of the Guide to the Expression of Uncertainty in Measurement. In this contribution, we demonstrate how to carry this out using the Monte Carlo method. The uncertainty evaluation involves various input quantities of different origin and the solution of a numerical optimisation problem. http://stacks.iop.org/0026-1394/55/i=2/a=S70?key=crossref.72255d5da84958e9d00890f4ec8e7d56 2018-03-09 0026-1394, 1681-7575 10.1088/1681-7575/aaa21b LeonardKlaus SaschaEichstädt article klausSeismometerCalibrationUsing2018 Journal of Physics: Conference Series 2018 1065 222014 Seismometers are widely used all over the world, but rarely calibrated traceably. PTB analysed its capabilities for seismometer calibration and identified its multi-component acceleration exciter as suitable for carrying the comparably heavy seismometers. Additionally, multi-axial seismometers can be calibrated in all axes without moving the device. The calibration device needed to be analysed and tested for the required small excitation magnitudes and low excitation frequencies. The results show that it is capable of generating small sinusoidal excitation of less than 1 mm/s in a frequency range down to 0.4 Hz. For this purpose, the feedback control needed to be adapted. Additionally, a temperature control of the shaker armature prevents the problem of temperature increase due to hot hydraulic fluids near the armature. The vibrations in all three translational degrees of freedom are measured by laser vibrometers and then processed according to ISO 16063-11 by sine fit procedures. http://stacks.iop.org/1742-6596/1065/i=22/a=222014?key=crossref.884fccaafa25014746cf7c9209f986a5 2018-11-20 1742-6588, 1742-6596 10.1088/1742-6596/1065/22/222014 LeonardKlaus MichaelKobusch article klausVibrationTestingAssess2018 Journal of Physics: Conference Series 2018 1065 222015 It is becoming increasingly important to assess the suitability for transportation of reference standards used for intercomparisons and of scientific devices developed to be transportable. For this purpose, normative documents were analysed in order to find a suitable test schedule, and two devices under test – one inductance standard and one optical cavity – were exposed to acceleration spectra simulating the typical transportation of each of the devices under test for different durations. The different devices under test are described and the motivation for the transport simulation is given. The results of the different tests are presented. http://stacks.iop.org/1742-6596/1065/i=22/a=222015?key=crossref.beb384b34a5727ce77a4fccc741552d8 2018-11-20 1742-6588, 1742-6596 10.1088/1742-6596/1065/22/222015 LeonardKlaus StephanHannig HaraldBothe techreport marekspoorsBestimmungTorsionssteifigkeitMittels2018 2018 Die Torsionssteifigkeit von mechanischen Komponenten ist im Bereich der Entwicklung eines modelbasierten Verfahrens zur Kalibrierung von Drehmomentaufnehmern mit dynamischer Anregung eine wichtige Information. Zur Ermittlung der Torsionssteifigkeit wurde ein speziell hierfür geeigneter Messplatz aufgebaut. Die vorliegende Arbeit beschreibt die Erweiterung des bereits vorhandenen Messplatzes für statische Torsionsbelastung durch optische Messmittel. Mit Hilfe der optischen Sensoren kann die Verdrehung während einer Drehmomentbelastung im Messobjekt gemessen werden. Mit dieser Information und dem gemessenen Drehmoment wird die Torsionssteifigkeit bestimmt. Im Rahmen der Arbeit wurde hierzu ein Messdatenauswertungsprogramm entwickelt, welches die Daten des Messplatzes auswertet und eine Plausibilitätsprüfung der Messwerte durchführt. Die Torsionssteifigkeit wird dabei durch eine Regressionsgerade beschrieben, die mittels des mathematischen Verfahrens, der Methode der kleinsten Quadrate (least square method), errechnet wurde. Für die gewonnenen Messwerte wurden abschließend die Einzelmessunsicherheitseinflüsse untersucht. https://web.ptb.de/cms/fileadmin/internet/fachabteilungen/abteilung_1/1.7_angewandte_akustik/1.73/Spoors_Bachelor_Thesis_Torsionssteifigkeit.pdf <prt>MarekSpoors</prt> article klausComparisonTwoExperiments2017 Measurement Science Review 2017 17 1 To determine the mass-moment-of-inertia properties of devices under test with particularly small mass moments of inertia (some 10−4 kg m2), two measurement set-ups based on different measurement principles were developed. One set-up is based on a physical pendulum, the second set-up incorporates a torsion pendulum. Both measurement set-ups and their measurement principles are described in detail, includingthe chosen data acquisition and analysis. Measurement uncertainty estimations according to the Guide to the Expression of Uncertainty in Measurement (GUM) were carried out for both set-ups by applying Monte Carlo simulations. Both set-ups were compared using the samethree devices under test. For each measurement result, the measurement uncertainties were estimated. The measurement results are comparedin terms of consistency and the resulting measurement uncertainties. For the given devices under test, the torsion pendulum set-up gave results with smaller measurement uncertainties compared to the set-up incorporating a physical pendulum. https://sciendo.com/article/10.1515/msr-2017-0002 2017-02-27 1335-8871 10.1515/msr-2017-0002 LeonardKlaus article kobuschCaseStudyModelbased2017 ACTA IMEKO 2017 6 1 3 Investigations of the model-based dynamic calibration of a small strain gauge force transducer of high bandwidth revealed new challenges for parameter identification. This paper discusses a more generalized mechanical model of the calibration set-up employed taking account of the transducer’s connection to its mechanical environment at both ends. Based on new experimental sine and shock force data, the improved model is studied and its parameters are identified. It is shown that the proposed model is capable of linking the calibration results of both calibration methods to a much better degree. This paper is an extended version of the original contribution to the IMEKO 2015 conference in Prague, Czech Republic. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-06%20%282017%29-01-02 2017-04-26 2221-870X 10.21014/acta_imeko.v6i1.433 MichaelKobusch SaschaEichstädt article qiaoFinalReportCCAUV2017 Metrologia 2017 54 1A 09001--09001 This is the final report for CIPM key comparison CCAUV.V-K3 in the area of 'vibration' (quantity of acceleration). The aim of this comparison was to measure the voltage sensitivity of one accelerometer standard set with primary means at 27 frequencies from 0.1 Hz to 40 Hz. Fourteen Metrology Institutes from five RMOs have participated in the comparison with National Institute of Metrology, P.R. China as pilot lab and Laboratoire National de Métrologie et d'Essais and National Metrology Institute of South Africa as co-pilot labs. One quartz-flexure servo accelerometer of single-ended type and a signal conditioner was circulated among the participants. All but one of the participating laboratories provided their calibration results, which were mostly consistent within their declared expanded uncertainties for magnitude results. Only two participants failed to contribute to the KCRV values calculated for five frequencies. For phase shift, three participants could not contribute to the calculation of the KCRV values in a total of sixteen frequencies. This first low-frequency vibration key comparison revealed the current calibration capabilities of the fourteen participants of five RMOs. http://stacks.iop.org/0026-1394/54/i=1A/a=09001?key=crossref.dcbea97487ff55f1890e9bdd545f0335 2017-02-27 0026-1394, 1681-7575 10.1088/0026-1394/54/1A/09001 SunQiao YangLifeng ClaireBartoli IanVeldman Gustavo PRipper ThomasBruns Torben RaskLicht JoannaKolasa ChristianHof Guillermo SilvaPineda LaurenceDickinson AkihiroOta Wan SupCheung AlexanderYankovsky CuiShan inproceedings kobuschInvestigationsImpactHammer2017 2017 This paper presents recent theoretical and experimental investigations of calibration measurements of impact hammers using different dynamic calibration set-ups with primary traceability methods. In the scope of a scientific collaboration between the German national metrology institute PTB and the Mexican CENAM, measurements of selected hammers were conducted at both institutes. The analysis of the measurement signals in the time and frequency domain is presented and discussed. http://www.imeko.org/publications/tc3-2017/IMEKO-TC3-2017-029.pdf

Helsinki, Finnland

Proc. of IMEKO TC3, TC5 and TC22 International Conference 2017 MichaelKobusch LeonardKlaus inproceedings brunsUsingOpenSource2017 2017 This paper describes the concept and implementation of a model based data analysis of primary shock calibration. The concept follows to a large extent the scheme of ISO 16063-43. In addition, it uses classical statistics to combine a number of measurements. The implementation is programmed in Python, i.e. using open source software, in particular a new tool box for the analysis of dynamic measurements, PyDynamic, which features the integrated handling of uncertainties in terms of covariances. http://www.imeko.org/publications/tc22-2017/IMEKO-TC22-2017-007.pdf

Helsinki, Finnland

Proc. of IMEKO TC3, TC5 and TC22 International Conference 2017 ThomasBruns HenrikVolkers SaschaEichstädt inproceedings klausNewCalibrationSetup2017 2017 Measurements of mechanical quantities are often carried out with transducers having a bridge output. These output signals are conditioned using bridge amplifiers. If dynamically changing quantities are going to be measured traceably, the bridge amplifier has to be calibrated dynamically. This paper describes a dynamic bridge amplifier calibration set-up based on the new PTB dynamic bridge standard. The calibration is carried out by synchronous sampling of the bridge amplifier output voltage and a reference signal provided by the calibrated dynamic bridge standard. The dynamic bridge standard enables calibrations in a frequency range from DC (static calibration) up to 10 kHz. An overview of the different measurement uncertainty contributions is given and the first measurement results show a good agreement with a previously established measurement set-up. http://www.imeko.org/publications/tc3-2017/IMEKO-TC3-2017-011.pdf

Helsinki, Finnland

Proc. of IMEKO TC3, TC5 and TC22 International Conference 2017 LeonardKlaus FlorianBeug ThomasBruns article brunsCorrectionShakerFlatness2016 Metrologia 2016 53 3 986--990 This paper describes the influence of a constant curvature of the shaker's air bearing guidance on a low frequency primary accelerometer calibration. Based on the mathematical model, three different methods are developed that allow a quantitative evaluation of this disturbing effect and thus the correction of the resulting systematic deviation. All three methods are applied to the example of a primary low frequency accelerometer calibration performed at PTB, and the results are given in comparison to the original uncorrected magnitude of sensitivity results. http://stacks.iop.org/0026-1394/53/i=3/a=986?key=crossref.812deadc9ba806d8ca35993505bc0e80 2016-10-24 0026-1394, 1681-7575 10.1088/0026-1394/53/3/986 ThomasBruns SusanneGazioch article klausModelParameterIdentification2016 ACTA IMEKO 2016 5 3 55 The dynamic calibration of torque transducers requires the modelling of the measuring device and of the transducer under test. The transducer's dynamic properties are described by means of model parameters, which are going to be identified from measurement data. To be able to do so, two transfer functions are calculated. In this paper, the transfer functions and the procedure for the model parameter identification are presented. Results of a parameter identification of a torque transducer are also given, and the validity of the identified parameters is analysed by comparing the results with independent measurements. The successful parameter identification is a prerequisite for a model-based dynamic calibration of torque transducers. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-05%20%282016%29-03-09 2016-11-07 2221-870X 10.21014/acta_imeko.v5i3.318 LeonardKlaus phdthesis klausEntwicklungPrimarenVerfahrens2016 2016 Dynamische Drehmomentverläufe, die mit entsprechenden Drehmomentaufnehmern erfasst werden sollen, treten bei verschiedenen Anwendungen auf. Soll das Drehmoment rückführbar gemessen werden, müssen diese Drehmomentaufnehmer dynamisch kalibriert werden. Derzeit existieren allein Verfahren zur statischen Kalibrierung von Drehmomentmesstechnik. Einflüsse durch die dynamischen Signalkomponenten werden -- ebenso wie die zugehörigen Messunsicherheitsbeiträge -- in der Praxis bisher vernachlässigt. Diese Arbeit beschreibt erstmals einen modellbasierten Ansatz zur dynamischen Drehmomentkalibrierung. Die mechanischen Eigenschaften des Aufnehmers, die das dynamische Verhalten beeinflussen, werden durch ein Modell und dessen Modellparameter beschrieben. Die Modellparameter sind charakteristische Kenngrößen für den Aufnehmer. Sie werden experimentell bestimmt. Die mechanischen Eigenschaften des Aufnehmers sind deshalb so wichtig, da Drehmomentaufnehmer immer an beiden Enden einspannt sind. Die im Wellenstrang mechanisch gekoppelten Komponenten können das dynamische Verhalten des Aufnehmers beeinflussen und umgekehrt. Der Drehmomentaufnehmer wird durch ein lineares, zeitinvariantes Modell beschrieben. Um die Modelleigenschaften bestimmen zu können, muss die Signalaufbereitungs- und Übertragungselektronik ebenfalls dynamisch kalibriert sein. So können diese Einflüsse kompensiert werden. Für alle Messungen werden Messunsicherheitsbetrachtungen angestellt und die Unsicherheit der bestimmten Modellparameter des Drehmomentaufnehmers abgeschätzt. http://dx.doi.org/10.7795/110.20160714 2016-07-15

Hannover

Leibniz Universität Hannover LeonardKlaus article klausleonardDynamicTorqueCalibration2015 PTB-Mitteilungen 2015 125 2 http://dx.doi.org/10.7795/310.20150203 2016-04-20 0030-834X 10.7795/310.20150203 Leonard</prt><prt>Klaus article kobuschmichaelCharacterizationForceTransducers2015 PTB-Mitteilungen 2015 125 2 http://dx.doi.org/10.7795/310.20150207 2016-04-20 10.7795/310.20150207 Michael</prt><prt>Kobusch article kobuschmichaelEuropeanResearchProject2015 PTB-Mitteilungen 2015 125 2 http://dx.doi.org/10.7795/310.20150202 2016-04-20 0030-834X 10.7795/310.20150202 Michael</prt><prt>Kobusch Thomas</prt><prt>Bruns article klausCalibrationBridgeCharge2015 Metrologia 2015 52 1 72--81 Measuring amplifiers are used for transducer output signal conditioning in many dynamic measurement applications. For a traceable measurement, a calibration of all components of the measuring chain—and therefore of the conditioning amplifiers, too—is mandatory. In this paper methods for a dynamic calibration of different types of conditioning amplifiers are presented. Measurement uncertainties and calibration results for typical amplifiers are discussed. http://stacks.iop.org/0026-1394/52/i=1/a=72?key=crossref.92d7d5fa34143fbb0ea5edb1589d97d2 2016-04-20 0026-1394, 1681-7575 10.1088/0026-1394/52/1/72 LeonardKlaus ThomasBruns HenrikVolkers article klausDynamicTorqueCalibration2015 Acta IMEKO 2015 4 2 39--44 For the dynamic calibration of torque transducers, a model of the transducer and an extended model of the mounted transducer including the measuring device have been developed. The dynamic behaviour of a torque transducer under test is going to be described by its model parameters. This paper describes the models with these known and unknown parameters and how the calibration measurements are going to be carried out. The principle for the identification of the transducer's model parameters from measurement data is described using a least squares approach. The influence of a variation of the transducer's parameters on the frequency response of the expanded model is analysed. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-04%20%282015%29-02-07 2221-870X LeonardKlaus BarboraArendacká MichaelKobusch ThomasBruns article kobuschInvestigationsModelbasedDynamic2015 Acta IMEKO 2015 4 2 42--51 Within the scope of the joint research project EMRP IND09 "Traceable dynamic measurements of mechanical quantities", numerous measurements were performed at PTB's 20 kN primary shock force calibration device to investigate and validate the approach of a model-based dynamic calibration of force transducers by using shock excitations. The tests included several strain gauge force transducers of greatly differing structural design, size, weight and mechanical coupling. By looking at a few examples, investigated physical models of the measurement set-up and developed data analysis procedures for parameter identification based on measured shock data are presented and discussed. The models reproduce the dynamic response including the observed modal oscillations of various origins that limit the usable measurement bandwidth. Moreover, these modal oscillations may have an important role for the parameter identification process, which is further discussed. This paper is an extended version of the original contribution to the IMEKO 2014 conference in Cape Town, South Africa. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-04%20%282015%29-02-08 2221-870X MichaelKobusch SaschaEichstädt LeonardKlaus ThomasBruns inproceedings nozatoNovelLowshockCalibration2015 2015 A piezoelectric accelerometer output voltage with zero shift was induced by the low-frequency response of the charge amplifier. So we designed a virtual amplifier with same input-output characteristic as the charge amplifier, and shock sensitivities of a piezoelectric accelerometer were evaluated by applying the input acceleration to the virtual amplifier. The shock sensitivities were comparable to the vibration calibration results. http://www.imeko.org/publications/wc-2015/IMEKO-WC-2015-TC22-437.pdf

Prag, Tschechische Republik

Proc. of XXI IMEKO World Congress "Measurement in Research and Industry" HideakiNozato AkihiroOta WataruKokuyama HenrikVolkers ThomasBruns inproceedings volkers2DOFModelBack2015 2015 By applying a two-degree-of-freedom system model (2-DOF) for an Endevco type 2270 back-to-back reference accelerometer, systematic deviations between measured and fitted 1-DOF transfer functions could be improved. Some key information for the identification of the model parameters is found in the frequency range beyond the first resonance, a range which was rarely considered in the past. www.imeko.org/publications/wc-2015/IMEKO-WC-2015-TC22-444.pdf

Prag, Tschechische Republik

Proc. of XXI IMEKO World Congress "Measurement in Research and Industry" HenrikVolkers ThomasBruns inproceedings klausComparisonHilbertTransform2015 2015 For the analysis of rotational damping measurements in the time domain, two different identification procedures are compared. The first procedure investigated incorporates a Hilbert transform of the data, which enables an analysis by a linear regression calculation. The second approach is a direct nonlinear regression calculation of a damped sine function. The two approaches are compared using both simulated data and measurement data. The results of the comparison are presented. www.imeko.org/publications/wc-2015/IMEKO-WC-2015-TC15-323.pdf

Prag, Tschechische Republik

Proc. of XXI IMEKO World Congress "Measurement in Research and Industry" LeonardKlaus inproceedings klausIdentificationModelParameters2015 2015 The dynamic calibration of torque transducers requires the modelling of the measuring device and of the transducer under test. The transducer’s dynamic properties are described by means of model parameters, which are going to be identified from measurement data. To be able to do so, two transfer functions are calculated. In this paper, the transfer functions and the procedure for the model parameter identification are presented. An example shows results of the parameter identification. www.imeko.org/publications/wc-2015/IMEKO-WC-2015-TC3-050.pdf

Prag, Tschechische Republik

Proc. of XXI IMEKO World Congress "Measurement in Research and Industry" LeonardKlaus inproceedings klausleonardModelBasedApproachDynamic2015 2015 The demand for traceable dynamic torque measurement has increased over the few last years. Procedures for the dynamic calibration of torque transducers have been developed in a European metrology research project. In the scope of this project, a dynamic measuring device was developed, and the corresponding mechanical modelling, which also includes the transducer under test, was investigated. The dynamic behaviour of the torque transducer is described by the parameters of its model. These model parameters will be identified from measurement data. The model-based approach for the description of the dynamic behaviour of torque transducers and model parameter identification procedures are described in this paper. http://dx.doi.org/10.7795/820.20150414K 2016-04-20

Orlando, USA

Proc. of IMAC XXXIII - A Conference and Exposition on Structural Dynamics 10.7795/820.20150414K Leonard</prt><prt>Klaus Michael</prt><prt>Kobusch Thomas</prt><prt>Bruns inproceedings kobuschChallengesModelbasedDynamic2015 2015 Investigations of the model-based dynamic calibration of a force transducer of high bandwidth revealed new challenges for parameter identification. This paper discusses a more generalized mechanical model of the calibration set-up employed. Based on new experimental sine and shock force data, the improved model is studied and its parameters are identified. It is shown that the proposed model is capable of linking the calibration results of both calibration methods to a much better degree. www.imeko.org/publications/wc-2015/IMEKO-WC-2015-TC3-053.pdf

Prag, Tschechische Republik

Proc. of XXI IMEKO World Congress "Measurement in Research and Industry" MichaelKobusch SaschaEichstädt article arendackaLinearMixedModels2014 Measurement Science Review 2014 14 2 In Annex H.5, the Guide to the Evaluation of Uncertainty in Measurement (GUM) [1] recognizes the necessity to analyze certain types of experiments by applying random effects ANOVA models. These belong to the more general family of linear mixed models that we focus on in the current paper. Extending the short introduction provided by the GUM, our aim is to show that the more general, linear mixed models cover a wider range of situations occurring in practice and can be beneficial when employed in data analysis of long-term repeated experiments. Namely, we point out their potential as an aid in establishing an uncertainty budget and as means for gaining more insight into the measurement process. We also comment on computational issues and to make the explanations less abstract, we illustrate all the concepts with the help of a measurement campaign conducted in order to challenge the uncertainty budget in calibration of accelerometers. https://sciendo.com/article/10.2478/msr-2014-0009 2016-04-20 1335-8871 10.2478/msr-2014-0009 BarboraArendacká AngelikaTäubner SaschaEichstädt ThomasBruns ClemensElster article klausModellingDynamicTorque2014 Acta IMEKO 2014 3 2 14--18 For the dynamic calibration of torque transducers, a calibration device has been developed. This paper describes the model of the measuring device and methods for the determination of its model parameters. The modelling of the calibration set-up is required for the identification of the corresponding model parameters of the torque transducer under test. These parameters describe the transducer's dynamic behaviour. Measurement methods and devices for the determination of mass moment of inertia and torsional stiffness are explained. This research is part of EMRP JRP IND09 - "Traceable Dynamic Measurement of Mechanical Quantities". acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-03%20%282014%29-02-05 2221-870X LeonardKlaus ThomasBruns MichaelKobusch article taubnerBilateralComparisonCCAUV2014 Metrologia 2014 51 1A 09006--09006 A comparison CCAUV.V-S1 was organized to compare measurements of sinusoidal angular accelerations in the frequency range from 0.4 Hz to 1 kHz. This was a bilateral comparison between the Korea Research Institute of Standards and Science (KRISS), Republic of Korea, and the Physikalisch-Technische Bundesanstalt (PTB), Germany. Both NMIs applied laser interferometry in compliance with ISO 16063-15:2006 'Methods for the calibration of vibration and shock transducers—Part 15: Primary angular vibration calibration by laser interferometry'. The complex voltage sensitivity (magnitude and phase) of one angular transfer standard in the frequency range of 0.4 Hz to 100 Hz and the complex charge sensitivity (magnitude and phase) of one angular reference standard in the frequency range of 1 Hz to 1000 Hz were measured. http://stacks.iop.org/0026-1394/51/i=1A/a=09006?key=crossref.922156b6d87cea56f7b9aac2a2e8b520 2016-05-09 1681-7575 10.1088/0026-1394/51/1A/09006 AngelikaTäubner ThomasBruns article volkersInfluenceSourceImpedance2014 ACTA IMEKO 2014 2 2 56 This contribution discusses the influence of the source impedance on the complex sensitivity of a charge amplifier (CA). During calibration of a CA with varying source impedances deviations at higher frequencies were observed, which if not properly taken into account may generate systematic errors beyond the limits of the measurement uncertainty budget. The contribution discusses a model to describe the effect as well as an extension to established CA calibration procedures which allow to quantify and correct the effect. https://acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-02%20%282013%29-02-10 2016-10-21 2221-870X 10.21014/acta_imeko.v2i2.81 HenrikVolkers ThomasBruns inproceedings bartoliDynamicCalibrationForce2014 2014 Nine European Metrology institutes (NMIs) are collaborating together to develop appropriate methods for the dynamic calibration of force, torque and pressure sensors which are only statically calibrated at present. This work is funded by the European Metrology Research Program (EMRP) within the scope of a dedicated research project which runs over three years. This article describes the current state of progress of the different parts of the project after its second year. http://www.imeko.org/publications/tc22-2014/IMEKO-TC3-TC22-2014-007.pdf

Kapstadt, Südafrika

Proc. of Joint IMEKO International TC3, TC5 and TC22 Conference 2014 ClaireBartoli FlorianBeug ThomasBruns SaschaEichstädt TrevorEsward LeonardKlaus AndyKnott MichaelKobusch ChristianSchlegel inproceedings klausExperimentalMethodNoncontact2014 2014 For a model-based description of the dynamic behaviour of a dynamic torque calibration device, it is necessary to determine the model parameters. This paper describes a method for the determination of damping properties with rotational excitation. To minimise the influence of the measurement, the oscillations were investigated by non-contact measurement. http://www.imeko.org/publications/tc22-2014/IMEKO-TC3-TC22-2014-003.pdf

Kapstadt, Südafrika

Proc. of Joint IMEKO International TC3, TC5 and TC22 Conference 2014 LeonardKlaus MichaelKobusch inproceedings brunsPrimaryAccelerationMeasurements2014 2014 The application of heterodyne interferometry with direct access to the frequency modulated signal was deemed unfeasible for low frequency vibration measurement, because of the trade-off between a carrier frequency and modulation bandwidth in the MHz range calling for high sampling rates on the one hand, and the low vibration frequency calling for long measuring times on the other hand. Data acquisition systems with the necessary amount of sample memory are expensive and the CPU time needed for the appropriate data processing becomes prohibitive at very low vibration frequencies. http://www.imeko.org/publications/tc22-2014/IMEKO-TC22-2014-004.pdf

Kapstadt, Südafrika

Proc. of Joint IMEKO International TC3, TC5 and TC22 Conference 2014 ThomasBruns FrankBlume HenrikVolkers inproceedings volkersInvestigationsReferenceSurface2014 2014 This paper describes the investigation of transducer reference surface warping during high shock calibrations using a Hopkinson bar and two laser Doppler vibrometer (LDV) and one LDV in conjunction with a laser Doppler scanning vibrometer. Dipole shocks up to 80 km/s² where applied to transfer standard back to back accelerometers with and without mass loads. http://www.imeko.org/publications/tc22-2014/IMEKO-TC22-2014-009.pdf

Kapstadt, Südafrika

Proc. of Joint IMEKO International TC3, TC5 and TC22 Conference 2014 HenrikVolkers TimoBeckmann ReinhardBehrendt inproceedings klausModelParameterIdentification2014 2014 For the dynamic calibration of torque transducers, a model of the transducer and an extended model of the mounted transducer with the measuring device have been developed. The dynamic behaviour of a torque transducer is described by model parameters. This paper describes the model with the known and unknown parameters and how the calibration measurements are going to be carried out. The principle for the identification of the transducer’s model parameters from measurement data is described using a least squares approach. http://www.imeko.org/publications/tc3-2014/IMEKO-TC3-2014-018.pdf

Kapstadt, Südafrika

Proc. of Joint IMEKO International TC3, TC5 and TC22 Conference 2014 LeonardKlaus BarboraArendacká MichaelKobusch ThomasBruns inproceedings kobuschInvestigationsModelbasedDynamic2014 2014 To investigate and validate the approach of a model-based dynamic calibration of force transducers by using shock excitations, numerous measurements were performed at PTB’s 20 kN primary shock force calibration device. The tests included several strain gauge force transducers of greatly differing structural design, size, weight and mechanical coupling. Previous studies proved modal oscillations of the measurement set-up of various origins that limit the usable bandwidth. Their effect on the modal-based calibration method with its data analysis procedures, which are to be developed, is further investigated and discussed in this paper. http://www.imeko.org/publications/tc22-2014/IMEKO-TC3-TC22-2014-005.pdf

Kapstadt, Südafrika

Proc. of Joint IMEKO International TC3, TC5 and TC22 Conference 2014 MichaelKobusch SaschaEichstädt LeonardKlaus ThomasBruns inproceedings kobuschProyectoInvestigacionEuropeo2014 2014 111--119 Este artículo presenta los resultados de un proyecto de investigación, en el que un total de nueve Institutos Nacionales de Metrología participaron para dar trazabilidad a la medición dinámica de tres magnitudes mecánicas, la fuerza, la presión y el par torsional. El trabajo se ha enfocado en el desarrollo de métodos trazables de calibración en dinámico, de modelos matemáticos, y de la evaluación de la incertidumbre de medida, considerando tanto los sensores mecánicos como los amplificadores eléctricos. Este proyecto comenzó en septiembre del 2011, duró tres años, y fue apoyado por el programa EMRP de la Unión Europea. http://www.cenam.mx/memorias/doctos/SM2014-018.pdf Centro Nacional de Metrología, (CENAM)

Querétaro, Mexiko

Simposio de Metrología Memorias 2014 MichaelKobusch ClaireBartoli FlorianBeug ThomasBruns SaschaEichstädt TrevorEsward LeonardKlaus AndyKnott NievesMedina article bartoliTraceableDynamicMeasurement2013 International Journal of Metrology and Quality Engineering 2013 3 3 127--135 Nine european national metrology institutes (NMIs) are collaborating in a new project funded by the european metrology research programme (EMRP) to establish traceable dynamic measurement of the mechanical quantities force, pressure, and torque. The aim of this joint research project (JRP) is to develop appropriate calibration methods, mathematical models, and uncertainty evaluation. The duration of the project is 3 years for a global amount of €3.6 million. It began in September 2011. http://www.metrology-journal.org/10.1051/ijmqe/2012020 2016-04-20 2107-6839, 2107-6847 10.1051/ijmqe/2012020 ClaireBartoli FlorianBeug ThomasBruns ClemensElster TrevorEsward LeonardKlaus AndyKnott MichaelKobusch SaariSaxholm ChristianSchlegel article kobusch250kNPrimaryShock2013 Measurement 2013 46 5 1757--1761 A new facility for primary shock force calibrations up to a force amplitude of 250 kN is presented. Shock forces are generated by the impact of two airborne cylindrical mass bodies. Two laser-Doppler interferometers simultaneously measure the bodies’ dynamic motions on their common axis of motion. Traceability of force is realised by the determination of mass and acceleration. This paper is an extended version of the original contribution to the IMEKO 2010 conference in Pattaya, Thailand. http://linkinghub.elsevier.com/retrieve/pii/S0263224112004666 2016-04-20 02632241 10.1016/j.measurement.2012.11.045 MichaelKobusch ThomasBruns LeonardKlaus MichaelMüller article brunsLinkingDynamicStatic2013 Metrologia 2013 50 6 580--585 The primary calibration of pressure transducers is at present realized by static methods. This paper describes a new route to gaining traceability for dynamic calibration using the acousto-optic effect. The pressure range under consideration is up to 100 MPa. We set out a description of the general principle employed to gain traceability, the experimental set-ups that are used for the realization and the thermophysical background of the measurements, and some numerical estimates on the expected results for two different pressure-transmitting media are shown. http://stacks.iop.org/0026-1394/50/i=6/a=580?key=crossref.d5ac0fedecfe062d8b1236be36691afa 2016-04-20 0026-1394, 1681-7575 10.1088/0026-1394/50/6/580 ThomasBruns ErnstFranke MichaelKobusch article nozatoStudySavitzkyGolayFilters2013 Acta IMEKO 2013 2 2 41--47 This manuscript reports the result of an investigation into two types of digital filters for numerical differentiation of the displacement signal in the case of primary shock calibration of accelerometers. The first is a difference method with a 4th-order Butterworth low-pass (4th BW) filter; the other is a Savitzky-Golay (S-G) filter, which applies a moving polynomial approximation. The computational comparison was applied to low and high amplitude shocks using known excitation functions. Each sum of residuals was compared for the optimized conditions of the 4th BW and S-G filters. The results of computer simulation indicated that the S-G filters exhibited better performance for the derivatives than the 4th BW filters. In addition, an analytical comparison using experimental vibration data also indicated that the S-G filters exhibited better derivative characteristics than the 4th BW filters. acta.imeko.org/index.php/acta-imeko/article/view/IMEKO-ACTA-02%20%282013%29-02-08 2221-870X 10.21014/acta_imeko.v2i2.62 HideakiNozato ThomasBruns HenrikVolkers AkihiroOota inproceedings arendackaRandomEffectsANOVA2013 2013 Random effects ANOVA models are well established and implemented in statistical software, they provide enough freedom to model dependencies between repeated measurements (e.g. a stronger dependency between measurements obtained within one day as compared to measurements obtained on different days) and they offer a closer look at the structure of the uncertainty (by splitting the variability due to different sources). The paper illustrates these concepts and advocates the use of random effects ANOVA models for analysis of long-term repeated experiments conducted to assess repeatability of a measurement. Variability revealed by such an experiment is important when creating an uncertainty budget. The concepts are illustrated with the help of data coming from calibration of accelerometers. http://www.measurement.sk/M2013/doc/proceedings/039_Arendacka-1.pdf

Smolenice, Slowakei

Proc. of 9th International Conference on Measurement BarboraArendacká AngelikaTäubner SaschaEichstädt ThomasBruns ClemensElster inproceedings klausleonardDynamicTorqueCalibration2013 2013 The demand for traceable dynamic measurements of mechanical quantities has increased over the last few years. In this context, methods for the dynamic calibration of torque transducers are under development. A measuring device for dynamic torque calibration is presented in this paper, and methods to model the dynamic behaviour of torque transducers as well as the measuring device are described. http://dx.doi.org/10.7795/810.20140929P 2016-04-20 10.7795/810.20140929P Leonard</prt><prt>Klaus Thomas</prt><prt>Bruns Michael</prt><prt>Kobusch article brunsInfluenceDifferentVibration2012 Metrologia 2012 49 1 27--31 During the monitoring of the long term stability of two accelerometers intended for use in the CIPM key comparison CCAUV.V-K2, significant deviations of the magnitude results of the single-ended transducer were discovered. These deviations depend on whether the calibration was performed on an armature made of beryllium or of ceramic. After first investigations which led to an interpretation as a relative motion effect published in Täubner et al (2010 Metrologia 47 58–64), now, more detailed measurements combined with modelling and system identification have led to a better understanding of what is happening. The measurements, model considerations and corresponding results are presented and discussed in order to further the understanding of this important issue of primary accelerometer calibration. This contribution can be considered a sequel to the former publication (Täubner et al 2010 Metrologia 47 58–64) on the topic. https://iopscience.iop.org/article/10.1088/0026-1394/49/1/005 2016-04-20 0026-1394, 1681-7575 10.1088/0026-1394/49/1/005 ThomasBruns AlfredLink AngelikaTäubner inproceedings bartoliTraceableDynamicMeasurement2012 2012 Nine European National Metrology Institutes (NMIs) are collaborating in a new project funded by the European Metrology Research Programme (EMRP) to establish traceable dynamic measurement of the mechanical quantities force, pressure, and torque. The aim of this joint research project (JRP) is to develop appropriate calibration methods, mathematical models, and uncertainty evaluation. The duration of the project is 3 years for a global amount of €3.6 million. It began in September 2011. www.imeko.org/publications/wc-2012/IMEKO-WC-2012-TC21-O7.pdf

Busan, Republik Korea

Proc. of XX IMEKO World Congress: Metrology for Green Growth ClaireBartoli ThomasBruns ClemensElster TrevorEsward LeonardKlaus AndyKnott SaariSaxholm ChristianSchlegel inproceedings brunsRealizationResultsDKD2012 2012 The standard ISO/IEC 17025:2005 [1] demands from calibration laboratories that the 'participation in a suitable programme of interlaboratory comparisons is required where possible'. In 2009, the working group of the German DKD concerned with acceleration and vibration decided to start such an interlaboratory comparison programme regarding the measurand acceleration and related quantities. This paper presents the set-up and organization as well as some combined results of this programme. www.imeko.org/publications/wc-2012/IMEKO-WC-2012-TC22-O1.pdf

Busan, Republik Korea

Proc. of XX IMEKO World Congress: Metrology for Green Growth ThomasBruns PhilipBegoff MichaelMende inproceedings klausDeterminationModelParameters2012 2012 For the dynamic calibration of torque transducers, a calibration device has been developed. This paper describes the model of the measuring device and methods for the determination of its model parameters. The modelling of the calibration set-up is required for the identification of the corresponding model parameters of the torque transducer under test. These parameters describe the transducer's dynamic behaviour. Measurement methods and devices for the determination of mass moment of inertia and torsional stiffness are explained. This research is part of EMRP JRP IND09 - “Traceable Dynamic Measurement of Mechanical Quantities”. www.imeko.org/publications/wc-2012/IMEKO-WC-2012-TC3-O33.pdf

Busan, Republik Korea

Proc. of XX IMEKO World Congress: Metrology for Green Growth LeonardKlaus ThomasBruns MichaelKobusch inproceedings kobuschModelbasedAnalysisDynamic2012 2012 An analysis of the dynamic behaviour of the 250 kN primary shock force calibration device at PTB is presented. Two airborne mass bodies with the force transducer under test are brought to collision, and the generated inertial forces are determined by means of laser vibrometers. Measurements with a heavy transducer revealed modal oscillations which were identified by acceleration sensors. The dynamic system behaviour was analysed with a finite element model. It showed that the elastic coupling between the transducer and the reference mass body causes low-frequency oscillations that have to be taken into account for calibration purposes. www.imeko.org/publications/wc-2012/IMEKO-WC-2012-TC3-O10.pdf

Busan, Republik Korea

Proc. of XX IMEKO World Congress: Metrology for Green Growth MichaelKobusch LeonardKlaus ThomasBruns inproceedings nozatoInvestigationSavitzkyGolayFilters2012 2012 This manuscript reports about an investigation of two kinds of digital filters used for numerical differentiation of the displacement signal in the case of primary shock calibration of accelerometers. One is a 4th order Butterworth low-pass (4th BW) filter of infinite impulse response filters, and another is a Savitzky-Golay (SG) filter, which applies local polynomial approximation. The computational comparison was applied to low and high shocks using known analytical excitation functions. On the optimized condition of 4th BW and S-G filters, each sum of residuals was compared. As the result, the S-G filters showed for low and high shocks a better performance as low-pass filter than the 4th BW filters. In addition, the appropriate window width for the local polynomial approximation was derived. www.imeko.org/publications/wc-2012/IMEKO-WC-2012-TC22-O9.pdf

Busan, Republik Korea

Proc. of XX IMEKO World Congress: Metrology for Green Growth HideakiNozato ThomasBruns HenrikVolkers AkihiroOota inproceedings volkersInfluenceSourceImpedance2012 2012 This contribution discusses the influence of the source impedance on the complex sensitivity of a charge amplifier (CA). During calibration of a CA with varying source impedances deviations at higher frequencies were observed, which if not properly taken into account may generate systematic errors beyond the limits of the measurement uncertainty budget. The contribution discusses a model to describe the effect as well as an extension to established CA calibration procedures which allow to quantify and correct the effect. www.imeko.org/publications/wc-2012/IMEKO-WC-2012-TC22-O6.pdf

Busan, Republik Korea

Proc. of XX IMEKO World Congress: Metrology for Green Growth HenrikVolkers ThomasBruns inproceedings bartoliTraceableDynamicMeasurement2011 2011

Paris, Frankreich

Proc. of 15th International Metrology Congress ClaireBartoli FlorianBeug ThomasBruns ClemensElster AndyKnott MichaelKobusch ChristianSchlegel inproceedings kobuschFacilitiesShockForce2011 2011

Peking, China

Proc. of CIMM-PTB Seminar on Dynamic Measurements and Nanometrology MichaelKobusch article brunsFinalReportKey2010 Metrologia 2010 47 1A 09001--09001 This report of the EUROMET.AUV.V-K1.1 comparison presents the final results of the second, follow-up EUROMET comparison in the area of vibration, in this case defined as sinusoidal acceleration. The relation between the results of the participants in this RMO comparison and the results of the first CIPM comparison in the field of vibration CCAUV.V-K1 is calculated via a procedure using one linking laboratory and is fully described. Using this linking, the results of the participants can be directly compared with the results of other comparisons, whether the CCAUV.V-K1 itself or others that are also linked such as the EUROMET.AUV.V-K1. The full uncertainty budgets are given in Appendix A and the Technical Protocol that was used is included as Appendix B. http://stacks.iop.org/0026-1394/47/i=1A/a=09001?key=crossref.10ccbff27ff111220865bf967a493552 2016-03-07 1681-7575 10.1088/0026-1394/47/1A/09001 ThomasBruns article brunsFinalReportKey2010a Metrologia 2010 47 1A 09002--09002 This report of the CCAUV.V-K1.1 key comparison (KC) presents the final results of the second, follow-up CIPM comparison in the area of vibration, in this case defined as sinusoidal acceleration. The relation between the results of the participants in this follow-up comparison and the results of the first CIPM comparison in the field of vibration CCAUV.V-K1 is calculated via a procedure using one linking laboratory and is fully described. Using this linking, the results of the participants can be directly compared with the results of other comparisons like CCAUV.V-K1. Supplementing the scope of the original CIPM comparison, the frequency range of the reported KC was extended up to 10 kHz and the measurand phase was included for some of the participants. The Technical Protocol that was used is included as Appendix A and the full uncertainty budgets are given in Appendix B. http://stacks.iop.org/0026-1394/47/i=1A/a=09002?key=crossref.4225c41923bf8fc1db4500ce29f0bf5d 2016-03-07 1681-7575 10.1088/0026-1394/47/1A/09002 ThomasBruns article eichstadtOnlineDynamicError2010 Measurement 2010 43 5 708--713 The output signal of an accelerometer typically contains dynamic errors when a broadband acceleration is applied. In order to determine the applied acceleration, post-processing of the accelerometer’s output signal is required. To this end, we propose the application of a digital FIR filter. We evaluate the uncertainty associated with the filtered output signal and give explicit formulae which allow for on-line calculation. In this way, estimation of the applied acceleration and the calculation of associated uncertainties may be carried out during the measurement. The resulting uncertainties can strongly depend on the design of the applied filter and we describe a simple method to construct an uncertainty-optimal filter. The benefit of the proposed procedures is illustrated by means of simulated measurements. http://linkinghub.elsevier.com/retrieve/pii/S0263224110000023 2016-03-07 02632241 10.1016/j.measurement.2009.12.028 SaschaEichstädt AlfredLink ThomasBruns ClemensElster article taubnerInfluenceDifferentVibration2010 Metrologia 2010 47 1 58--64 During the monitoring of the long term stability of two accelerometers intended for use in the CIPM Key Comparison CCAUV.V-K2, significant deviations of the magnitude results of the single-ended transducer were discovered. These deviations depend on whether the calibration was performed on an armature made of beryllium or of ceramic. Further investigations showed that this effect must be attributed to some not yet readily understood dynamic process between the contact surfaces of the accelerometer and the armature. The relative motion underlying the deviations has a significant systematic influence already at 5 kHz and beyond. Therefore, the effect needs to be considered in some way while comparing results within the key comparison, as some laboratories use beryllium armatures and some use ceramic armatures. The contribution describes the details and outcome of the investigations performed on the topic so far and is intended to trigger the necessary discussion on consequences and solutions. http://stacks.iop.org/0026-1394/47/i=1/a=007?key=crossref.fdf52eebb3090ac903c88b6fedbc2e52 2016-03-07 0026-1394, 1681-7575 10.1088/0026-1394/47/1/007 AngelikaTäubner Hans-JoachimSchlaak MartinBrucke ThomasBruns inproceedings kobusch250KilonewtonPrimary2010 2010 9--11 A new facility for primary shock force calibrations up to 250 kN force amplitude is presented. Shock forces are generated by the impact of two airborne cylindrical mass bodies. Two laser-Doppler interferometers simultaneously measure the bodies’ dynamic motions on their axes of motion. Traceability of force is realised by the determination of mass and acceleration. www.imeko.org/publications/tc3-2010/IMEKO-TC3-2010-003.pdf

Pattaya, Thailand

Proc. of IMEKO TC3 &amp; TC5 &amp; TC22 International Conference MichaelKobusch ThomasBruns LeonardKlaus MichaelMüller inproceedings brunsOptoelectronicPhaseDelay2010 2010 237--239 For the primary calibration of the phase response of accelerometers, the knowledge of the response delay of the reference, i.e. the laser interferometer is a decisive prerequisite. However, an experimental determination of the interferometric response time is not a simple task. This contribution describes an opto-electronic set-up based on a femtosecond laser and originally developed for calibration of high speed sampling oscilloscopes, which enables a precise determination of the intrinsic delay of the photo detectors of a modified Michelson interferometer used at PTB. www.imeko.org/publications/tc22-2010/IMEKO-TC22-2010-NP-008.pdf

Pattaya, Thailand

Proc. of IMEKO TC3 &amp; TC5 &amp; TC22 International Conference ThomasBruns FrankBlume KaiBaaske MarkBieler HenrikVolkers article blumePrimaryPhaseCalibration2009 Metrologia 2009 46 5 489--495 A set-up for the calibration of a heterodyne laser-vibrometer is described. By a distinctive optical set-up it is possible to use the laser of the device under test as the single source for the calibration device. In this way many difficulties of the optical adjustment usually encountered in set-ups for laser-vibrometer calibration are avoided and exceptionally low measurement uncertainties are achieved. This article describes the set-up for the case of a commercially available device which is additionally modified to provide the means for primary traceability. The measurement results are discussed for the analogue output usually used in industrial applications as well as for the output of the photodetector signal, which is used if the device is part of a primary calibration system. Special attention is given to the provisions necessary to achieve low measurement uncertainties. https://iopscience.iop.org/article/10.1088/0026-1394/46/5/013 2016-03-07 0026-1394, 1681-7575 10.1088/0026-1394/46/5/013 FrankBlume AngelikaTäubner UweGöbel ThomasBruns article kobuschMicrocalorimeterArrayMeasurement2009 Thermochimica Acta 2009 492 1-2 89--94 This paper describes a novel calorimetric measurement method for the in situ measurement of the kinetic energy of micrometer-sized particles in space. An incoming particle hits the detector area with a typical velocity of about 10 km/s and the resulting impact heating of the absorber material is measured by an array of microcalorimeters utilizing a 16 × 16 array of thermopile heat power sensors. Experimental tests with accelerated dust particles as well as with laser pulses have proven the capability of this measurement principle. The detection threshold for heat deposition is about 10 nJ for a gold absorber of 2.8 μm thickness. At the moment, a flight model of the calorimetric particle detector is being developed and will be ready to be launched into space in the near future. http://linkinghub.elsevier.com/retrieve/pii/S0040603109001361 2016-03-07 00406031 10.1016/j.tca.2009.03.008 MichaelKobusch StefanSarge Karl DietrichBunte TorstenFichna DanielHagedorn FrankJäger RudolfMeeß article wegenerTraceabilityTorqueTransducers2009 Measurement 2009 42 10 1448--1453 Torque transducers in industrial applications are usually used under dynamic and rotating operating conditions. The present article provides a survey of state-of-the-art studies which describe methods for providing traceability of torque measurements under such operating conditions. The method of investigating the effects of rotation is a comparison of measurements of torque in a rotating shaft train gained simultaneously with two different methods. The first method is using a rotating torque transducer, the second one is with a cradle-mounted absorption dynamometer. The method for investigating the effects of dynamic torque is based on experiments with periodic torque but only minimal rotational motion. Torque is generated by a rotary exciter which forces a setup with a torque transducer and some auxiliary components into a periodic rotary motion. The torque measurement provided by the torque transducer is compared to a reference torque. The reference torque is gained by accurately measuring the angular acceleration of the rotation in conjunction with a priori knowledge of the mass moment of inertia. The developments on the periodic dynamic torque have been performed by the Physikalisch-Technische Bundesanstalt (PTB), the German National Metrology Institute. The investigations on rotating torque transducers have been performed by Hottinger Baldwin Messtechnik (HBM), Germany, a manufacturer of torque transducers with a wide experience in torque calibration. http://linkinghub.elsevier.com/retrieve/pii/S0263224109001675 2016-03-07 02632241 10.1016/j.measurement.2009.08.007 GeorgWegener ThomasBruns inproceedings brunsCalibrationAccelerometersUsing2009 2009 The currently established documentary standards for primary accelerometer calibration provide a characterisation of the device under test which is not well suited for the application to transient excitations. The model based parameter dentification (MBPI) introduced over the last years may provide better means of characterisation for such types of applications. The method was recently validated with extensive measurement series in a joint research project between PTB and the company “SPEKTRA Schwingungstechnik und Akustik GmbH Dresden” and is now considered by the authors to be ready for practical use and worthwhile to be standardized on an ISO level. This contribution will shortly re-visit the methodology of MBPI, report on the validation process and finally describe the current effort to implement a new ISO documentary standard on the topic. http://www.imeko.org/publications/wc-2009/IMEKO-WC-2009-TC22-118.pdf

Lissabon, Portugal

Proc. of XIX IMEKO World Congress: Fundamental and Applied Metrology 978-963-88410-0-1 ThomasBruns AlfredLink FrankoSchählig HolgerNicklich ClemensElster inproceedings brunsLaserVibrometerCalibration2009 2009 The calibration of Laser vibrometer is an increasing demand in industry and research. The equipment suggested for use in particular for high frequency calibration, however, is typically of prototype stage and not commercially available. This is due to the demand of the employed homodyne quadrature method for a certain minimum displacement, typically a quarter of a wavelength, of the vibrating object. The authors demonstrate that this is not necessarily a compulsory condition. With conventional, commercially available components it is possible to set-up a system for Laser vibrometer calibration up to 90 kHz. This could be achieved by employing a distinctive optical set-up combined with an unusual (dual frequency) excitation and an improved or extended signal processing. http://www.imeko.org/publications/wc-2009/IMEKO-WC-2009-TC22-495.pdf

Lissabon, Portugal

Proc. of XIX IMEKO World Congress: Fundamental and Applied Metrology 978-963-88410-0-1 ThomasBruns FrankBlume AngelikaTäubner inproceedings volkersDarfBisschenGenauer2009 2009 Begleitband Zum Kongress VIP 2009 978-3-7785-4057-2 HenrikVolkers inproceedings elsterRealtimeDynamicError2009 2009 The output signal of an accelerometer typically contains dynamic errors when a broadband acceleration is applied. In order to retrieve the applied acceleration, post-processing of the accelerometer’s output signal is required. To this end, we propose the application of a digital filter. We describe the construction of an appropriate filter and consider the uncertainty associated with the filtered output signal. Explicit formulae can be employed to calculate both, the filtered output sig nal and its associated uncertainty, in real-time. We illustrate the need and benefit of the proposed approach in terms of an example. http://www.imeko.org/publications/wc-2009/IMEKO-WC-2009-TC22-058.pdf

Lissabon, Portugal

Proc. of XIX IMEKO World Congress: Fundamental and Applied Metrology 978-963-88410-0-1 ClemensElster SaschaEichstädt AlfredLink ThomasBruns inproceedings herbstInsituDetectorAIDA2009 2009 In-situ detection of space debris and meteoroid particles is a method which was applied to gain knowledge of non-trackable small objects since the early days of spaceflight. Although the instruments in most cases only allow the measurement of particles in the size range of some micrometers due to size restrictions of the sensors, the available - but sparse - results are insightful: The small-particle population can be seen as a tracer to the population of larger non-trackable objects, and it was possible to confirm the correctness of model assumptions for solid rocket motor firing spacecraft cannot be neglected. Existing in-situ detectors for micro-sized particles in the Earth’s environment do not operate satisfactorily due to incompatibilities of the measurement principles with the space environment. For this reason the development of the Advanced Impact Detector Assembly - AIDA - was initiated to overcome the shortcomings of these instruments. Breadboard models have proven the high sensitivity of the measurement principles which are also expected to be less susceptible to environmental influences. Based on these results, the establishment of a development model has been initiated. Details of the sensor layout, the manufacturing process and the test results are presented. Some suggestions for the deployment of AIDA and future developments to obtain a fully operational instrument are outlined.

Darmstadt

Proceedings of the Fifth European Conference on Space Debris 978-92-9221-236-0 ChristianHerbst Karl DietrichBunte TorstenFichna DanielHagedorn GregorHemken ErnstKeßler MichaelKobusch inproceedings kobuschChallengesPracticalDynamic2008 2008 78 201--212 High precision calibration of electromechanical transducers using dynamic loads is a field of rapidly growing demand in industries. But in contrast, the number of validated methods or even written standards is still close to negligible considering the number of measurands concerned. For this reason, the Physikalisch-Technische Bundesanstalt (PTB) has put increasing effort into the field of dynamic measurement of mechanical quantities in the past several years. The dynamic measurands covered so far by this R&amp;D initiative include acceleration, angular acceleration, dynamic force, pressure and torque. New dynamic calibration facilities have been developed, applying either periodic or shock excitations and using either primary or secondary calibration methods. The working principles of these calibration devices are described subsequently as well as the different approaches for the dynamic characterization of transducers, like step response, impulse response or harmonic response, respectively. From the scientific point of view, the harmonization of different dynamic calibration results is an essential requisite towards future standardization work. Despite the different technical realizations, the mathematical procedures and the problems for a dynamic characterization of transducers as well as the dissemination of the dynamic units are generally similar. These challenges are now approached by methods of a model-based calibration, which seem to give very promising results. World Scientific

Paris

Series on Advances in Mathematics for Applied Sciences Advanced Mathematical and Computational Tools in Metrology and Testing : AMCTM VIII 978-981-283-951-0 MichaelKobusch ThomasBruns ErnstFranke inproceedings wubbelerImpactCorrelationMeasured2008 2008 78 369--374 The dynamic behaviour of accelerometers can be described in terms of a second-order model. The parameters of this model may be estimated from a measurement of the frequency response of the accelerometer as obtained in a dynamic calibration measurement. The impact of correlations of the measured frequency response on the results obtained from a subsequent analysis of this data is studied. Possible correlations are considered which arise from correlations of magnitude and phase measurements at the same frequency as well as from a common systematic influence. By using data from a dynamic calibration measurement it is shown that the considered correlations can have a large influence on the results and that they should be taken into account. World Scientific

Paris

Series on Advances in Mathematics for Applied Sciences Advanced Mathematical and Computational Tools in Metrology and Testing : AMCTM VIII 978-981-283-951-0 GerdWübbeler AlfredLink ThomasBruns ClemensElster