Citation:
F. Combet and L. Gelman, An automated methodology for performing time
synchronous averaging of a gearbox signal without speed sensor, Mechanical
Systems and Signal Processing, Volume 21, Issue 6, August 2007, Pages 2590-2606.
Abstract:
In this paper we extend a sensorless algorithm proposed by Bonnardot et al. for
angular resampling of the acceleration signal of a gearbox submitted to limited
speed fluctuation. The previous algorithm estimates the shaft angular position
by narrow-band demodulation of one harmonic of the mesh frequency. The harmonic
was chosen by trial and error. This paper proposes a solution to select
automatically the mesh harmonic used for the shaft angular position estimation.
To do so it evaluates the local signal-to-noise ratio associated to the mesh
harmonic and deduces the associated low-pass filtering effect on the time
synchronous average (TSA) of the signal. Results are compared with the TSA
obtained when using a tachometer on an industrial gearbox used for wastewater
treatment. The proposed methodology requires only the knowledge of an
approximate value of the running speed and the number of teeth of the gears. It
forms an automated scheme which can prove useful for real-time diagnostic
applications based on TSA where speed measurement is not possible or not
advisable due to difficult environmental conditions.