Virtual tachometers based on time series filtering
A system and method for receiving a plurality of first inputs from a transducer, where the plurality of first inputs correspond to vibrations of a rotational machine, and filtering the plurality of first inputs to derive a frequency of interest. The system and method then generates a sinusoidal signal at the frequency of interest and a pulse train of one or multiple pulses per revolution at the frequency of interest from the sinusoidal signal. The system and method further identifies a first pulse at a zero crossing within the pulse train and counts zero crossings to define blocks of data for use in time synchronous averaging calculations.
1. A computing device, configured to:
receive a plurality of first inputs from a transducer, the plurality of first inputs corresponding to vibrations of a rotational machine;
wide band-pass filter the plurality of first inputs from the transducer;
identify at least one zero-crossing of the wide band-pass filtered plurality of first inputs;
mark each zero-crossing as a tachometer pulse to calculate an estimated shaft speed;
narrow band-pass filter the plurality of first inputs from the transduced based on the estimated shaft speed to generate a sinusoidal signal at a frequency of interest;
identify zero crossings in the sinusoidal signal;
generate a pulse train of multiple pulses per revolution at the frequency of interest from the zero crossings;
identify a first pulse at a zero crossing within the zero crossings; and
count the zero crossings to define blocks of data for use in time synchronous averaging calculations.
2. The computing device of claim 1 , wherein the rotational machine is a gearbox, and wherein the transducer is an accelerometer configured to detect the vibrations of the gear box and output the vibrations to the computing device.
3. The computing device of claim 1 , wherein the frequency of interest corresponds to a component of the rotational machine.
4. The computing device of claim 1 , further configured to:
identify a shaft speed of the rotational device based on the identified zero-crossings.
5. The computing device of claim 1 , further configured to:
process the frequency of interest in support of condition monitoring of the rotational machine.
6. The computing device of claim 1 , wherein the computing device is a high speed tachometer.
7. The system of claim 1 , wherein the computing device is further configured to output a notification based on the estimated shaft speed to a system or user responsible for the rotational machine.
8. The system of claim 1 , wherein the rotational machine is carried by an aircraft.
9. A method, comprising:
receiving, by a computing device, a plurality of first inputs from a transducer, the plurality of first inputs corresponding to vibrations of a rotational machine;
wide band-pass filtering on the plurality of first inputs;
identifying, by the computing device, at least one zero-crossing of the wide-band filtered plurality of first inputs;
marking, by the computing device, each zero-crossing as a tachometer pulse to calculate an estimated shaft speed;
narrow band-pass filtering on the plurality of first inputs based on the estimated shaft speed to generate, by the computing device, a sinusoidal signal at a frequency of interest;
identifying, by the computing device, zero crossing in the sinusoidal signal;
generating, by the computing device, a pulse train of multiple pulses per revolution at the frequency of interest from the sinusoidal signal from the zero crossings;
identifying, by the computing device, a first pulse at a zero crossing within the zero crossings; and
counting, by the computing device, the zero crossings to define blocks of data for use in time synchronous averaging calculations.
10. The method of claim 9 , wherein rotational machine is a gearbox and the transducer is an accelerometer, and further comprising,
detecting the vibrations of the gearbox; and
outputting the vibrations to the computing device.
11. The method of claim 9 , wherein the frequency of interest corresponds to a component of the rotational machine.
12. The method of claim 9 , further comprising:
identifying a rotational speed of the rotational device based on the identified zero-crossings.
13. The method of claim 9 , further comprising:
processing the frequency of interest in support of condition monitoring of the rotational machine.
14. The method of claim 9 , wherein the computing device is a virtual high speed tachometer.
15. The method of claim 9 , further comprising outputting a notification based on the estimated shaft speed to a system or user responsible for the rotational machine.