volume | PIER Journals

Abstract

This paper deals with the measurement of the magnetic flux generated by the armature of electromagnetic rail launchers linked with external pick-up loops. In particular we discuss possible methods to experimentally evaluate measurement uncertainty when the magnetic flux is obtained by numerical voltage integration. These methods aim at an approximate identification of the correlation among voltage samples introduced by the analog-to-digital converter, only based on the available measurements without requiring additional tests and instruments. An estimate of this correlation allows to better evaluate the overall measurement uncertainty, thus providing the applicability limits of the proposed inductive technique and contributing to a better understanding of the current and force distribution in the armature.

1. Novotny, M. and M. Sedlacek, "RMS value measurement based on classical and modified digital signal processing algorithms," Measurement, Vol. 41, 236-250, 2008.
doi:10.1016/j.measurement.2006.11.011 Google Scholar

2. Novotny, M., D. Slepicka, and M. Sedlacek, "Uncertainty analysis of the RMS value and phase in the frequency domain by noncoherent sampling," IEEE Trans. Instrum. Meas., Vol. 56, No. 3, 983-989, 2007.
doi:10.1109/TIM.2007.894189 Google Scholar

3. Xi, J. and J. F. Chicharo, "A new algorithm for improving the accuracy of periodic signal analysis," IEEE Trans. Instrum. Meas., Vol. 45, No. 4, 827-830, 1996.
doi:10.1109/19.517004 Google Scholar

4. Betta, G., C. Liguori, and A. Pietrosanto, "Propagation of uncertainty in a discrete Fourier transform algorithm," Measurement, Vol. 27, 231-239, 2000.
doi:10.1016/S0263-2241(99)00068-8 Google Scholar

5. Attivissimo, F., N. Giaquinto, M. Marracci, and B. Tellini, "Effect and compensation of ADC nonlinearity on magnetic accommodation measurements," Measurement, Vol. 46, No. 3, 1340-1348, 2013.
doi:10.1016/j.measurement.2012.11.006 Google Scholar

6. Ferrero, R., M. Marracci, and B. Tellini, "Characterization of inductance gradient and current distribution in electromagnetic launchers," IEEE Trans. Instrum. Meas., Vol. 60, No. 5, 1795-1801, 2011.
doi:10.1109/TIM.2010.2091186 Google Scholar

7. Ferrero, R., M. Marracci, and B. Tellini, "Uncertainty analysis of local and integral methods for current distribution measurements," IEEE Trans. Instrum. Meas., Vol. 62, No. 1, 177-184, 2013.
doi:10.1109/TIM.2012.2212503 Google Scholar

8. Ferrero, R., M. Marracci, and B. Tellini, "Dynamic experiments of current distribution in rail launcher multi-brush armatures," Proc. IMTC, 1-5, Graz, Austria, May 13-16, 2012. Google Scholar

9. Ferrero, R., M. Marracci, and B. Tellini, "Current distribution measurements in rail launcher multibrush armatures during launch," IEEE Trans. Instrum. Meas., Vol. 62, No. 5, 1138-1144, 2013.
doi:10.1109/TIM.2012.2220038 Google Scholar

10. Cordero, R. R., G. Seckmeyer, D. Pissulla, and F. Labbe, "Uncertainty of experimental integrals: Application to the UV index calculation," Metrologia, Vol. 45, 1-10, 2008.
doi:10.1088/0026-1394/45/1/001 Google Scholar

11. Edwards, T. S., "Effects of aliasing on numerical integration," Mechanical Systems and Signal Processing, Vol. 21, 165-176, 2007.
doi:10.1016/j.ymssp.2005.08.009 Google Scholar

12. BIPM JCGM 100:2008 "Evaluation of measurement data --- Guide to the expression of uncertainty in measurement,", GUM 1995 with Minor Corrections, 2008. Google Scholar

13. Pogliano, U., "Traceability of electrical quantities obtained by sampling," Measurement, Vol. 42, 1439-1442, 2009.
doi:10.1016/j.measurement.2009.07.018 Google Scholar

14. Pogliano, U., "Evaluation of the uncertainties in the measurement of distorted power by means of the IEN sampling system," IEEE Trans. Instrum. Meas., Vol. 55, No. 2, 620-624, 2006.
doi:10.1109/TIM.2006.870129 Google Scholar

15. Nuccio, S. and C. Spataro, "Approaches to evaluate the virtual instrumentation measurement uncertainties," IEEE Trans. Instrum. Meas., Vol. 51, No. 6, 1347-1352, 2002.
doi:10.1109/TIM.2002.808036 Google Scholar

16. Locci, N., C. Muscas, and E. Ghiani, "Evaluation of uncertainty in measurements based on digitalized data," Measurement, Vol. 32, 265-272, 2002.
doi:10.1016/S0263-2241(02)00034-9 Google Scholar

17. Ferrero, R., M. Marracci, and B. Tellini, "Analytical study of impulse current measuring shunts with cage confiuration," IEEE Trans. Instrum. Meas., Vol. 61, No. 5, 1260-1267, 2012.
doi:10.1109/TIM.2011.2175823 Google Scholar

Dr. Roberto Ferrero

Dr. Mirko Marracci

Prof. Bernardo Tellini