US 2012/0072136 A1 · APPARATUS AND A METHOD FOR ANALYSING THE VIBRATION OF A MACHINE HAVING A ROTATING PART

Abstract

An apparatus for analyzing the condition of a machine having a part rotatable with a speed of rotation, includes an input for receiving an analogue measurement signal indicative of a vibration signal signature having a vibration frequency and a repetition frequency; an A/D converter for generating a digital measurement signal dependent on the analogue measurement signal, the digital measurement signal having a first sample rate, which is at least twice the vibration frequency; an enveloper for generating an enveloped signal indicative of the repetition frequency; a decimator for generating a decimated first digital signal dependent on the enveloped signal such that the decimated first digital signal has a reduced sample rate; an enhancer having an input for receiving the decimated signal, wherein the enhancer operates in the time domain to perform discrete autocorrelation for the decimated first digital signal so as to generate an enhancer output signal sequence; and an analyzer for performing a condition monitoring function so as to analyze the condition of the machine dependent on the output signal sequence.

Claims43

Dependent claims

An apparatus for analysing the condition of a machine having a part rotatable with a speed of rotation (fROT), comprising

an input (42) for receiving an analogue measurement signal (SEA) indicative of a vibration signal signature having a vibration frequency (fSEA) and a repetition frequency (fD);
an A/D converter (40, 44) for generating a digital measurement signal (SMD)) dependent on the analogue measurement signal, said digital measurement signal (SMD) having a first sample rate (fS), the first sample rate being at least twice (k) said vibration frequency (fSEA);
an enveloper (250, 94) for generating an enveloped signal indicative of said repetition frequency (fD);
a decimator (310, 94) for generating a decimated first digital signal (SRED, SRED1, SRED2) dependent on said enveloped signal such that said decimated first digital signal has a reduced sample rate (fSR);
an enhancer having an input for receiving said decimated signal, wherein the enhancer (320) operates in the time domain to perform discrete autocorrelation for the decimated first digital signal (SRED, SRED1, SRED2) so as to generate an enhancer output signal sequence (O, SMDP);
and
an analyzer (290;
290T, 294, 290F) for performing a condition monitoring function (F1, F2, Fn) so as to analyse the condition of the machine dependent on said enhancer output signal sequence (O, SMDP).

5 more elements

An apparatus for analysing the condition of a machine having a part rotatable with a speed of rotation (fROT), comprising

A first input (315) for receiving a first digital signal (SRED, SMD, SENV) dependent on mechanical vibrations emanating from rotation of said part;
said first digital signal (SRED) having a sample rate (fSR);
wherein said first digital signal (SRED, SMD, SENV) may include noise and a first signal signature (SD1) having a first repetition frequency (fD1);
an enhancer (320) for processing a first plurality (ILENGTH) of input sample values of said first digital signal (SRED, SMD, SENV) so as to generate an output signal sequence (O, SMHP) having a second plurality (OLENGTH) of output sample values (SMDP(t));
said second plurality being a positive integer;
an analyzer (290;
290T, 294, 290F) for performing a condition monitoring function (F1, F2, Fn) so as to analyse the condition of the machine dependent on said output signal sequence (O, SMDP);
wherein the enhancer (320) includes:
at least one second input (335, 350, 360, 364) for receiving data (Z, Y, fSR, fROT, OLENGTH) indicative of said second plurality (OLENGTH);
and
an output (394, 396, 398) for delivering said output signal sequence (O, SMDP);
wherein
said enhancer (320, 382, 386) is adapted to generate an output sample value (SMDP(t)) in dependence on a third plurality (CLENGTH) of input signal products (P(i,t));
said third plurality (CLENGTH) being a positive integer;
wherein an input signal product (P(i,t)) for an output sample position t is obtained by multiplying a first input sample value (I(i)) at a first sample position (i) with a second input sample value (I(i+t+SSTART)) at a second sample position (i+t+SSTART) said second input sample value being separated from said first input sample value by a certain number (t+SSTART) of sample positions, wherein said certain number is equal to, or larger than a certain value (SSTART);
the enhancer further comprising:
at least one third input (335, 366) for receiving data indicative of a Signal-to-Noise Ratio improver value (L);
and
means (365, 375;
375B) for generating a data value indicative of said third plurality (CLENGTH) in dependence on
said Signal-to-Noise Ratio improver value (L) and
said data (Z, Y, fSR, fROT) indicative of said second plurality (OLENGTH).

19 more elements

An apparatus for analysing the condition of a machine having a part rotatable with a speed of rotation (fROT), comprising

a first input (315) for receiving a first digital signal (SRED, SMD, SENV) dependent on mechanical vibrations emanating from rotation of said part;
said first digital signal (SRED) having a sample rate (fSR);
wherein said first digital signal (SRED, SMD, SENV) may include noise and a first signal signature (SD1) having a first repetition frequency (fD1);
an enhancer (320) for processing a first plurality (ILENGTH) of input sample values of said first digital signal (SRED, SMD, SENV) so as to generate an output signal sequence (O, SMDP) having a second plurality (OLENGTH) of output sample values (SMDP(t));
said second plurality being a positive integer;
an analyzer (290;
290T, 294, 290F) for performing a condition monitoring function (F1, F2, Fn) so as to analyse the condition of the machine dependent on said output signal sequence (O, SMDP);
wherein the enhancer (320) includes:
at least one second input (335, 350, 360, 364) for receiving data (Z, Y, fSR, fROT, OLENGTH) indicative of said second plurality (OLENGTH);
and
an output (394, 396, 398) for delivering said output signal sequence (O, SMDP);
wherein
said enhancer (320, 382, 386) is adapted to generate an output sample value (SMDP(t)) in accordance with the expression:
S
MDP
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(
t
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=
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i
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i
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0
i
=
i
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+
CLENGTH
-
1

I
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(
i
)
*
I
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(
i
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Sstart
+
t
)
Or in accordance with the expression:
S
MDP

(
t
)
=
∑
i
=
i
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0
i
=
i
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+
CLENGTH
-
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I
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(
i
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I
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i
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Sstart
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t
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wherein
SSTART is an integer having a value equal to, or greater than, said second plurality value (OLENGTH);
CLENGTH is an integer;
and
i0 is a constant integer;
and wherein the enhancer further comprises:
at least one third input (335, 366) for receiving data indicative of a Signal-to-Noise Ratio improver value (L);
and
means (365, 375;
375B) for generating a data value indicative of said integer value CLENGTH in dependence of
said Signal-to-Noise Ratio improver value (L) and
said data (Z, Y, fSR, fROT) indicative of said second plurality (OLENGTH).

103 more elements

A method for analysing the condition of a machine having a part rotating with a speed of rotation (fROT), comprising the steps of:

receiving a first digital signal (SRED, SMD, SENv) dependent on mechanical vibrations emanating from rotation of said part;
said first digital signal (SRED) having a sample rate (fSR);
wherein said first digital signal (SRED, SMD, SENV) may include noise and a first signal signature (SD1) having a first repetition frequency (fD1) and a second signal signature (SD2) having a second repetition frequency (fD2), further comprising:
processing a first plurality (ILENGTH) of input sample values of said first digital signal (SRED, SMD, SENV) so as to generate an output signal sequence (O, SMDP) having a second plurality (OLENGTH) of output sample values (SMDP(t)), wherein
an individual input sample value (I(i)) is addressable by an input sample position value (i), and
an individual output sample value ((SMDP(t)), O(t)) is addressable by an output sample position value (t);
and wherein
the processing step includes:
A) generating an output sample value SMDP(t) for an output sample position t, said output sample value generating step including:
Performing a third plurality (CLENGTH) of multiplications to produce input signal products;
wherein an input signal product is obtained by multiplying a first input sample value (I(i)) at a first sample position (i) with a second input sample value (I(i2), I(i+SSTART+t+t0);
I(i−SSTART+t+t0)) at a second sample position (i2), said second input sample value (I(i+SSTART+t0);
I(i−SSTART+t0)) being separated from said first input sample value (I(i)) by a certain number (SSTART+t) of sample positions;
said certain number being equal to, or larger than, a certain value (SSTART);
and
Adding said third plurality (CLENGTH) of input signal products to produce a sum of input signal products;
said sum of input signal products being the output sample value SMDP(t) for said sample position t;
and
Delivering said output sample value SMDP(t) for said sample position t;
B) repeating step A) for substantially all said output sample position values (t) such that said output signal sequence (O, SMDP) is generated;
said method further comprising:
performing a condition monitoring function (F1, F2, Fn) so as to analyse the condition of the machine dependent on said output signal sequence (O, SMDP).

19 more elements

A method of operating an apparatus for analysing the condition of a machine having a part rotating with a speed of rotation (fROT), comprising the steps of:

receiving a first digital signal (SRED, SMD, SENV) dependent on mechanical vibrations emanating from rotation of said part;
said first digital signal (SRED) having a sample rate (fSR);
processing a first plurality (ILENGTH) of input sample values of said first digital signal (SRED, SMD, SENV) so as to generate an output signal sequence (O, SMDP) having a second plurality (OLENGTH) of output sample values (SMDP(t)), wherein
an individual input sample value (I(i)) is addressable by an input sample position value (i), and
an individual output sample value ((SMDP(t)), O(t)) is addressable by an output sample position value (t);
wherein the processing step includes
1) setting the output sample position value (t) to an initial value (t0);
2) generating an output sample value (SMDP(t)) for the relevant sample position (t), said output sample value generating step including:
a) setting the input sample position value (i) to an initial value (i0);
b) generating an input signal product (P(i,t)) by multiplying a first input sample value (I(i)) at a first sample position (i) with a second input sample value (I(i2), I (i+SSTART+t0);
I (i−SSTART+t0)) at a second sample position (i2), said second input sample value (I(i+SSTART+t0);
I(i−SSTART+t0)) being separated from said first input sample value (I(i)) by a certain number (SSTART+t) of sample positions;
said certain number being larger than a certain value (SSTART);
and
c) changing the input sample position value (i) by one step;
d) repeating step b) so as to generate another input signal product (P(i,t)) and creating a sum of the generated input signal products;
wherein
e) step d) is repeated until a third plurality (CLENGTH) of input signal products (P(i,t)) have been summed;
f) setting the output sample value (SMDP(t)), relating to the output sample position (t) indicated by the output sample position value (t), in dependence of the sum of the generated input signal products (P(i,t));
g) delivering the output sample value (SMDP(t)), relating to the output sample position (t) indicated by the output sample position value (t);
3) changing the output sample position value (t) by one step;
4) repeating step 2) until at least said second plurality (OLENGTH) of output sample values (SMDP(t)) have been delivered;
the method further comprising:
performing a condition monitoring function (F1, F2, Fn) so as to analyse the condition of the machine dependent on said output signal sequence (O, SMDP).

21 more elements

Dependencies are inferred from the claim text.

Apparatus and a method for analysing the vibration of a machine having a rotating part

Life of this patent

Apparatus and a method for analysing the vibration of a machine having a rotating part

Life of this patent

Abstract

Claims43