JPS61272808A - Abnormality diagnostic device - Google Patents

Abstract

PURPOSE:To perform the diagnosis independent of the frequency band of the input-side quantity of state by differentiating input and output quantities of state of a diagnosis object to obtain variance values and performing the abnormality diagnosis in accordance with a ratio of input and output variance values. CONSTITUTION:Input and output are detected by sensors 12 and 13 and are differentiated by differentiators 14 and 15, and variance values are obtained by variance value computing elements 16 and 17. The ratio is obtained from outputs 18 and 19, and it is compared by a comparator 12 whether this ratio is within a designated range or not. The output is compared with a designated value by a comparator 22, and an AND circuit 23 is opened to display the output of the comparator 21 on the display device 28 if the output 18 is larger. If the output 18 is smaller, an AND circuit 26 is opened to display a value, which is obtained from a comparator 25 and indicates whether the output 19 is larger than a designated value or not, on the display device 28.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention can be used without depending on the frequency band width of the state quantity on the input side to be diagnosed, and even when no noise is superimposed on the input side. The present invention relates to an abnormality diagnosis device capable of diagnosing abnormalities.

[Conventional technology]

Figure 2 shows the flow of operation of a conventional abnormality diagnosis device, in which the state quantity and the output state quantity are detected by sensors 2 and 3, respectively, and the detected outputs of both sensors 2 and 3 are detected by Stella f4, which is the input value. A correlation function and a cross-correlation function between input and output are determined, and from these, a spectral density is calculated in step 5, and a transfer function is calculated in step 6.

Next, in step 7, the transfer function when the diagnostic target I is normal is determined by a parameter, and the value obtained by adding a certain range to the value of each meter is used as the reference value, and the value decreases to Stella f8. Use this as a threshold for comparison.

In the diagnosis, it is checked from time to time whether the determined transfer function parameter exceeds the above-mentioned threshold value, and when the parameter exceeds the threshold value, an abnormality is displayed on Stella f9.

Further, if the mother 2 meter does not exceed the threshold value at Stella f8, the process returns to Stella f4 and the above-mentioned calculation is repeated.

[Problem that the invention seeks to solve]

In order to prevent erroneous diagnosis when diagnosing an abnormality using a conventional abnormality diagnosis device, the movement of the state quantity on the input side of the diagnostic target I must have characteristics similar to white noise, and it must be limited to normal operation. No.

This is because, in order to accurately determine the transfer function, the state quantity on the input side of the diagnostic target must include a broadband frequency component, and a large amount of data is required. Must continue for a long time.

This invention was made in order to eliminate the above-mentioned conventional drawbacks, and it is possible to perform diagnosis without depending on the frequency band width of the state quantity on the input side to be diagnosed, and also to avoid noise being superimposed on the input side. It is an object of the present invention to provide an abnormality diagnosis device capable of diagnosing an abnormality of a diagnosis target even when there is no abnormality.

[Means for solving problems]

The abnormality diagnosis device of the present invention includes a first differentiator that differentiates a state quantity of an input to be diagnosed, and a value differentiated by the first differentiator from the current time to an average value within a specified past period of time. a first dispersion value calculator for calculating a dispersion value, a second differentiator for differentiating the state quantity of the output of the diagnosis target;
A second variance value calculator that calculates the variance value, which takes the value differentiated by the differentiator as the average value within a specified past period of time from the present time, and the first and second variance value calculators described above. A ratio calculator that calculates the ratio of variance values is compared with whether the ratio calculated by this ratio calculator is within a predetermined range, and if it is outside the range, outputs a logical value rIJ, and if it is outside the range, outputs a logical value rIJ. a first comparator outputting a logical value "0";
a second comparator that outputs a logical value "l" when the variance value calculated by the variance value calculator is smaller than a predetermined specified value; and a second comparator that outputs a logical value "0"otherwise; a third comparator that outputs a logical value "1" when the variance value calculated by the variance value calculation unit No. 2 is thicker than a predetermined designated value, and outputs a logical value "0"otherwise; The output of the first comparator and the second
a first AND circuit that performs logical product with the output of the comparator;
A second AND circuit that takes the logical product of the NOT operation result of the output of the second comparator and the output of the third comparator, and a logical sum of the outputs of the first and second AND circuits. 1"
The system is equipped with an abnormality diagnosis result display that displays an abnormality when.

[Effect]

In this invention, the state quantity of the input to be diagnosed is detected by the first sensor and differentiated by the first differentiator, and the variance value calculator of the apprentice 1 calculates the average value within a specified past period of time from the present time. After calculating the variance value, detecting the state quantity of the output to be diagnosed with the second sensor and differentiating it with the second differentiator, the second variance value calculator calculates the average value within a specified past period of time from the current time. A variance value to be used as a value is determined, a ratio of the variance values determined by the first and second variance value calculators is determined by a ratio calculator, and a first comparator determines whether this ratio is within a predetermined range. If it is outside the predetermined range, the first comparator outputs a logical value "1", and if it is not within the range, it outputs the logical value rOJ, and the first and second variance calculation units calculate the The second and second variance values are respectively
The third comparator compares it with a predetermined specified value, and when it is larger than this specified value, outputs a logical value "1", otherwise outputs a logical value rOJ, and the output of the first comparator and second
The logical AND with the output of the comparator is taken by the first piece circuit, and the second
When the logical product of the NOT operation result of the output of the comparator and the output of the third comparator is performed in the second piece circuit, and the logical sum of the outputs of the first and second circuits is "l", An error is displayed on the error diagnosis result display.

〔Example〕

Embodiments of the abnormality diagnosis device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment. In FIG. 1, the state quantity of the input X of the diagnostic target II is input to the first sensor 12. The state quantity of the output y of I is input to the second sensor I3.

The output of the first sensor I2 is sent to a first differentiator I4, and the output of the second sensor I3 is sent to a second differentiator I5.

The output of the first differentiator f4 is output to the variance value calculator I6,
The output of the second differentiator I5 is output to the second variance value calculator I7.

The output I8 of the first variance value calculator 16 and the output I9 of the second variance value calculator I7 are sent to the ratio calculator 20.

Further, the output of the first variance value calculator 16 is transmitted to the second comparator 2.
Similarly, the output of the second dispersion value calculator I7 is sent to the third comparator 25.

The ratio calculator 20 calculates the ratio between the output 18 of the first variance calculator I6 and the output 19 of the second variance calculator I7,
The signal is output to the first comparator 2I.

The output of the first comparator 2I and the output of the second comparator 22 are sent to the first AND circuit 23, and the second
The output of the comparator 22 is passed through the NOT circuit 24 to the second A
The signal is sent to the ND circuit 26.

The output of the third comparator 25 and the output of the NOT circuit 24 are
The output of the first AND circuit 23 is also sent to the OR circuit 27. The output of the OR circuit 27 is output to an abnormality diagnosis result display 28.

Next, the operation of the abnormality diagnosis apparatus of the present invention configured as described above will be explained. The state quantity of the input X of the diagnostic object II is detected by the first sensor I2, and its detection output is
Differentiate with a differentiator 14.

The value differentiated by the first differentiator I4 is used to obtain a variance value by a first variance value calculator I6. This variance value is an average value within a specified past period of time from the current time. The variance value calculated by the first variance value calculator I6, ie, the output I8, is sent to the ratio calculator 20 and the second comparator 22.

On the other hand, the output y of the diagnostic target 11 is also detected in the same manner as the input It is sent to the variance value calculator I7, where the variance value is determined.

In this case as well, similarly to the first variance value calculator I2, the variance value is the average value within a specified past period of time from the present time. The output I of this second variance value calculator 12
9 is sent to the ratio calculator 20 and at the same time, it is also sent to the second comparator 25.

The ratio calculator 20 receives the output Z8 of the first variance value calculator I6.
When σx1 is the output 19fσy of the second variance value calculator I7, the ratio σy/σX of this output 18.19 is determined by the ratio calculator 20. This ratio σy/σX is determined by the first comparator 2
Sent to I.

This first comparator 21 has a value α specified by the ratio σyρ−X.
1. A comparison is made to see if it is within the range of α2.

If the result of this comparison is outside the specified range, the logical value "1"
” is output to the first AND circuit 23. Moreover, if the comparison result is other than that, a logical value rOJ is output.

That is, if the comparison result is α2〉σy/ax〉α, then
A logical value "0" is output, and a logical value "1" is output otherwise. However, α2>α1.

Further, the second comparator 22 inputs the output 18 (σX) of the first variance value calculator I6, and if the value is larger than the specified value β, the logical value "1" is sent to the first AND circuit. 23 and N
Otherwise, the logical value rOJ is output to the first AND circuit 23 and the NOT circuit 24.

The first AND circuit 23 connects the output of the first comparator 2I and the second
The comparator 22 calculates the output 'ff:' and sends it to the OR circuit 27.

Furthermore, the NOT circuit 24 performs a NOT operation on the output of the second comparator 22 and outputs the result to the second AND circuit 26 .

On the other hand, the third comparator 25 inputs the output I(σy) of the second variance value calculator I7, and if the value is larger than the specified value β2, outputs a logical value "1". , otherwise outputs the logical value "OJ."
A D operation is performed and its output is output to the OR circuit 27.

This OR circuit 27 connects the output of the first AND circuit 23 and the second
An OR operation is performed on the outputs of the AND circuit 26 and the result is output to the abnormality diagnosis result display 28. This abnormality diagnosis result display 2
8, it is possible to indicate that an abnormality has occurred in the diagnostic object II when the output of the OR circuit 2'7 becomes the logical value rlJ.

〔Effect of the invention〕

As described above, according to the abnormality diagnosis device of the present invention, the variance value of the value obtained by differentiating the state quantity of the input and output to be diagnosed is obtained, and the abnormality diagnosis is performed based on the ratio of the variance value between the input and output. , diagnosis can be performed without depending on the frequency band width of the state quantity on the input side as in the conventional case.

Further, even when noise is not superimposed on the input/output side of the diagnostic target, the dispersion value of the output of the diagnostic target is utilized, so an abnormality can be diagnosed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the abnormality diagnosing apparatus of the present invention, and FIG. 2 is a flowchart showing the operation flow of the conventional abnormality diagnosing apparatus. II... Abnormal object, I2... First sensor, I3.
...Second sensor, I4...First differentiator, 15...
・Second differentiator, I6...first variance value calculator, I7
...Second variance value calculator, 20...Ratio calculator, 2
1... First comparator, 22... Second comparator, 23
...First AND circuit, 24...NOT circuit, 25
...Third comparator, 26...Second piece circuit, 27.
...OR circuit, 28...Abnormality diagnosis result display. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] A first differentiator that differentiates the state quantity of the input to be diagnosed, and a first differentiator that calculates a variance value that takes the value differentiated by the first differentiator as an average value within a specified past period of time from the present time. A variance value calculator, a second differentiator that differentiates the state quantity of the output of the above-mentioned diagnosis target, and the value differentiated by this second differentiator is set as an average value within a specified past period of time from the present time. a second variance value calculator for calculating a variance value, and the first and second
A ratio calculator that calculates the ratio of the variance values calculated by the variance value calculator compares whether or not the ratio calculated by this ratio calculator is within a predetermined range, and if it is outside the range, a logical value of "1" is set. ” and outputs a logical value “0” if the value is other than that, and a logical value “0” when the variance value calculated by the first variance calculator is larger than a predetermined specified value. a second comparator that outputs ``1'' and a logical value ``0''otherwise; and a logical value when the variance value obtained by the second variance value calculator is larger than a predetermined specified value. a third comparator that outputs "1" and a logic value "0"otherwise; and a third comparator that takes the AND of the output of the first comparator and the output of the second comparator. 1 AND circuit and the output of the second comparator
A second AND circuit that takes the logical product of the OT operation result and the output of the third comparator, and an abnormality that displays an abnormality when the logical sum of the outputs of the first and second AND circuits is "1" An abnormality diagnosis device comprising a diagnosis result display device.