The primary objective of this these was to study the feasibility of using a MEMS accelerometer to monitor vibration signatures of a machine to determine if the machine is operating properly. The secondary objective was to investigate the self test features of the accelerometer used in the vibration monitoring. An Efector Octavis accelerometer sensor was used in this study. It was used to monitor a small air pump and an air conditioning (AC) system. The sensor provided the amplitude for the frequency spectrum of the motor vibration. A reference signal was calculated by taking an average of the spectrum over 30 seconds. Two methods (a ratio of cross-correlation coefficients and a spectral distance) were used to compare the reference to the sensor data. The spectral distance method proved to be the better of the two. Using this method, the system could sense when the pump or the AC unit were malfunctioning. The self test feature involved exciting the Built in Self Test (BIST) pin of the accelerometer with a signal generator. Then the impulse response of the accelerometer was measured from the output pin using an oscilloscope.
| Identifer | oai:union.ndltd.org:nps.edu/oai:calhoun.nps.edu:10945/2409 |
| Date | 12 1900 |
| Creators | Young, Jonathan C. |
| Contributors | Yun, Xiaoping, Cristi, Roberto., Naval Postgraduate School (U.S.)., Department of Electrical and Computer Engineering |
| Publisher | Monterey California. Naval Postgraduate School |
| Source Sets | Naval Postgraduate School |
| Detected Language | English |
| Type | Thesis |
| Format | xviii, 41 p. : ill. ;, application/pdf |
| Rights | Approved for public release, distribution unlimited |
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