A Smart Resonant Sensor Fabricated by Si MST for Online Vibration Control of Rotating Machinery

In this contribution we present a vibration-measurement system based on a micromechanical resonant vibration sensor for online control of rotating machinery. The monolithic sensor module realized by Si MST (Si microsystems technique) consists of a mechanical resonator, a piezoresistive bridge, and a PMOS amplifier. Due to the high sensitivity of the sensor when operated close to resonance the measured time-dependent signal is dominated by excitation frequencies from this spectral range. These frequencies can be determined directly from the measured signal by a fitting procedure. Thus the large amount of redundant data of the vibration spectra measured with an antifriction bearing is condensed to the significant information and a fast and effective control of wear of rotating machinery can be performed.