KR102225195B1 - An Outputing Method of Overload Value of Machine Tool and Rotating Body Fault Diagnosis Method using the same - Google Patents

Abstract

The present invention includes the steps of measuring acceleration data in a steady state and acceleration data in an abnormal state for each axis; Calculating a ratio of a standard deviation for acceleration data in a steady state and a standard deviation for acceleration data in an abnormal state for each of the axes; Calculating a tool load value for each axis through the ratio of the standard deviation; And calculating a total tool load value through the tool load value for each axis, and a method for diagnosing an abnormality in a rotating body using the same. A method for calculating a tool load value may be provided, and a method for diagnosing an abnormality in a rotating body for diagnosing an abnormality in the rotating body may be provided by using this.

Description

An Outputing Method of Overload Value of Machine Tool and Rotating Body Fault Diagnosis Method using the same}

The present invention relates to a method of calculating a tool load value and a method of diagnosing an abnormality in a rotating body using the same, and more particularly, a method of calculating a tool load value capable of diagnosing an abnormality of a tool through a new method of calculating a tool load value, and using the same. It relates to a method for diagnosing an abnormality in a rotating body.

In general, in the case of a rotating machine, an abnormality occurs due to various causes, and when such an abnormality occurs, manufacturing defects are caused or damage to the corresponding machine is caused, requiring rapid maintenance.

Accordingly, conventionally, various methods for detecting the occurrence of an abnormality in a rotating body machine have been proposed, and in relation to this, Korean Patent No. 10-0942287, Korean Patent No. 10-0199105, and Japanese Patent Laid-Open No. 1997- 113416, Japanese Patent No. 3449194, etc. are disclosed.

That is, in the related art, a method of diagnosing an abnormality of a rotating machine by using the vibration data or sound data after detecting it has been mainly used.

However, the above-described conventional techniques simply diagnose the normality of the rotating body machine, the cause of the abnormality, or the damaged part, and have not been able to diagnose the lifespan of the rotating body machine to cope with the delay.

In other words, in the conventional technology, it is only possible to confirm this when the rotating body machine is damaged, but it is not possible to predict the risk of damage to the relevant part before the damage is done, so the response in case of damage is inevitably slow. There is always a problem that productivity is inevitably lowered.

In particular, in the case of machine tools, high speed and high precision are being made in order to improve processing productivity and quality, so it will be more necessary to maintain the optimum state and target accuracy of machine tools and products.If cost reduction is considered, more than a rotating body (e.g., spindle) There is a great demand for diagnostic technology.

Korean Patent Registration 10-1865897

An object to be solved by the present invention is to provide a new method of calculating a tool load value for diagnosing an abnormality in a tool.

In addition, an object of the present invention is to provide a method for diagnosing an abnormality in a rotating body for diagnosing an abnormality in a rotating body using a new method of calculating a tool load value.

The objects of the present invention are not limited to the objects mentioned above, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above-noted problem, the present invention includes measuring acceleration data in a steady state and acceleration data in an abnormal state for each axis; Calculating a ratio of a standard deviation for acceleration data in a steady state and a standard deviation for acceleration data in an abnormal state for each of the axes; Calculating a tool load value for each axis through the ratio of the standard deviation; And calculating a total tool load value through the tool load value for each axis.

In addition, in the present invention, each of the axes includes an x-axis, a y-axis, and a z-axis, and the ratio of the standard deviation for acceleration data in a steady state and the standard deviation for acceleration data in an abnormal state for each of the axes is, The ratio of the standard deviation of the x-axis, which is the ratio of the standard deviation of the steady state and the standard deviation of the abnormal state, the ratio of the standard deviation of the y-axis, which is the ratio of the standard deviation of the steady state and the standard deviation of the abnormal state, and the standard deviation of the z-axis, It includes the ratio of the standard deviation of the z-axis, which is the ratio of the standard deviation of the abnormal state, and the ratio of the standard deviation of the x-axis is defined by the following equation (1), and the ratio of the standard deviation of the y-axis is expressed by the following equation (2). It is defined, and the ratio of the standard deviation of the z-axis provides a method of calculating a tool load value defined by Equation (3) below.

... 수학식 (1)

... Equation (1)

(However, in Equation (1), α _x is the ratio of the standard deviation of the x-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _x,n is the normal standard deviation of the x-axis, σ _x,f Is the ideal standard deviation of the x-axis)

... 수학식 (2)

... Equation (2)

(However, in Equation (2), α _y is the ratio of the standard deviation of the y-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _y,n is the normal standard deviation of the y-axis, σ _y,f Is the ideal standard deviation of the y-axis)

... 수학식 (3)

... Equation (3)

(However, in Equation (3), α _z is the ratio of the standard deviation of the z-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _z,n is the normal standard deviation of the z-axis, σ _z,f Is the ideal standard deviation of the z-axis)

In addition, in the present invention, the tool load value for each axis includes the tool load value of the x-axis, the tool load value of the y-axis, and the tool load value of the z-axis, and the tool load value of the x-axis is Equation (4) The tool load value of the y-axis is defined by Equation (5) below, and the tool load value of the z-axis provides a method of calculating a tool load value defined by Equation (6) below.

... 수학식 (4)

... Equation (4)

(However, in Equation (4), F _x is the tool load value of the x-axis, α _x is the ratio of the standard deviation of the x-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _x is the acceleration data of the abnormal state of the x axis, μ _x,f is the average of the acceleration data of the abnormal state of the x axis, and σ _x,f is the standard deviation of the acceleration data of the abnormal state of the x axis)

... 수학식 (5)

... Equation (5)

(However, in Equation (5), F _y is the tool load value of the y-axis, α _y is the ratio of the standard deviation of the y-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _y is the acceleration data of the abnormal state of the y-axis, μ _y,f is the average of the acceleration data of the abnormal state of the y-axis, and σ _y,f is the standard deviation of the acceleration data of the abnormal state of the y-axis)

... 수학식 (6)

... Equation (6)

(However, in Equation (6), F _z is the tool load value of the z-axis, α _z is the ratio of the standard deviation of the z-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _z is the acceleration data of the abnormal state of the z axis, μ _z,f is the average of the acceleration data of the abnormal state of the z axis, σ _z,f is the standard deviation of the acceleration data of the abnormal state of the z axis)

In addition, the present invention provides a method of calculating a tool load value, wherein the total tool load value is defined by Equation (7) below.

...수학식 (7)

...Equation (7)

(However, in Equation (7), Ft is the total tool load value, F _x is the tool load value on the x-axis, F _y is the tool load value on the y-axis, and F _z is the tool load value on the z-axis)

_{In addition, the present invention corresponds to F y} = 0, F _z = 0 when only the tool load value of the x-axis is considered in Equation (7), and the total tool load value is defined by Equation (8) below. In Equation (7), when only the tool load value of the y-axis is considered, it _{corresponds to F x} = 0 and F _z = 0, and the total tool load value is defined by Equation (9) below, wherein In Equation (7), when only the tool load value of the z-axis is considered, it _{corresponds to F x} = 0 and F _y = 0, and the total tool load value is a method of calculating a tool load value defined by Equation (9) below. Provides.

...수학식(8)

...Equation (8)

...수학식(9)

...Equation (9)

...수학식 (10)

...Equation (10)

In addition, the present invention comprises the steps of measuring acceleration data in a normal state and acceleration data in an abnormal state for a short axis; Calculating a ratio of a standard deviation for acceleration data in a steady state and a standard deviation for acceleration data in an abnormal state for the short axis; And calculating a tool load value for the short axis through the ratio of the standard deviation.

In addition, the present invention relates to the ratio of the standard deviation of the short axis, which is the ratio of the standard deviation of the acceleration data in the steady state and the standard deviation of the acceleration data in the abnormal state, with respect to the short axis, defined by Equation (10) below. Provides a method of calculating the load value.

... 수학식 (10)

... Equation (10)

(However, in Equation (10), α is the ratio of the standard deviation of _{the corresponding minor axis, σ n} is the standard deviation for the steady state acceleration data of the _{corresponding minor axis, and σ f} is the standard for the acceleration data in the abnormal state of the corresponding minor axis. Deviation)

In addition, the present invention provides a method of calculating a tool load value, which is calculated through the ratio of the standard deviation, and the tool load value for the short axis is defined by Equation (11) below.

...수학식(11)

...Equation (11)

(However, in Equation (11), F is the tool load value in the minor axis direction, α is the ratio of the standard deviation of the minor axis, X is the acceleration data _{of the abnormal state of the corresponding minor axis, and μ f} is the abnormal state of the corresponding minor axis. The average of the acceleration data, σ _f is the standard deviation of the acceleration data in the abnormal state of the short axis)

In addition, in the present invention, the short axis is an x-axis, y-axis, or z-axis, and the criterion for selecting which axis of the x-axis, the y-axis, and the z-axis to calculate the tool load value is, the The standard deviation of the acceleration data in the abnormal state of any one of the x-axis, the y-axis, and the z-axis is used as the denominator, and the standard deviation of the acceleration data in the abnormal state of the other two axes is used as the numerator. A tool load value calculation method is provided in which a ratio is calculated and a value having a large ideal standard deviation ratio is selected as a criterion for calculating the tool load value.

In addition, the present invention provides a total tool load value according to Equation (7) below.

...수학식 (7)

...Equation (7)

(However, in Equation (7), Ft is the total tool load value, F _x is the tool load value on the x-axis, F _y is the tool load value on the y-axis, and F _z is the tool load value on the z-axis)

In addition, in the present invention, the tool load value of the x-axis is defined by the following equation (4), the tool load value of the y-axis is defined by the following equation (5), and the tool load value of the z-axis is expressed by the following equation ( Provides the tool load value defined as 6).

... 수학식 (4)

... Equation (4)

(However, in Equation (4), F _x is the tool load value of the x-axis, α _x is the ratio of the standard deviation of the x-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _x is the acceleration data of the abnormal state of the x axis, μ _x,f is the average of the acceleration data of the abnormal state of the x axis, and σ _x,f is the standard deviation of the acceleration data of the abnormal state of the x axis)

... 수학식 (5)

... Equation (5)

(However, in Equation (5), F _y is the tool load value of the y-axis, α _y is the ratio of the standard deviation of the y-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _y is the acceleration data of the abnormal state of the y-axis, μ _y,f is the average of the acceleration data of the abnormal state of the y-axis, and σ _y,f is the standard deviation of the acceleration data of the abnormal state of the y-axis)

... 수학식 (6)

... Equation (6)

(However, in Equation (6), F _z is the tool load value of the z-axis, α _z is the ratio of the standard deviation of the z-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _z is the acceleration data of the abnormal state of the z axis, μ _z,f is the average of the acceleration data of the abnormal state of the z axis, σ _z,f is the standard deviation of the acceleration data of the abnormal state of the z axis)

In addition, in the present invention, the ratio of the standard deviation of the x-axis is defined by the following Equation (1), the ratio of the standard deviation of the y-axis is defined by the following Equation (2), and the ratio of the standard deviation of the z-axis is Provides a tool load value defined by Equation (3).

... 수학식 (1)

... Equation (1)

(However, in Equation (1), α _x is the ratio of the standard deviation of the x-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _x,n is the normal standard deviation of the x-axis, σ _x,f Is the ideal standard deviation of the x-axis)

... 수학식 (2)

... Equation (2)

(However, in Equation (2), α _y is the ratio of the standard deviation of the y-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _y,n is the normal standard deviation of the y-axis, σ _y,f Is the ideal standard deviation of the y-axis)

... 수학식 (3)

... Equation (3)

(However, in Equation (3), α _z is the ratio of the standard deviation of the z-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _z,n is the normal standard deviation of the z-axis, σ _z,f Is the ideal standard deviation of the z-axis)

In addition, the present invention provides a tool load value according to the following equation (11).

...수학식(11)

...Equation (11)

(However, in Equation (11), F is the tool load value in the minor axis direction, α is the ratio of the standard deviation of the minor axis, X is the acceleration data _{of the abnormal state of the corresponding minor axis, and μ f} is the abnormal state of the corresponding minor axis. The average of the acceleration data, σ _f is the standard deviation of the acceleration data in the abnormal state of the short axis)

In addition, the present invention provides the ratio of the standard deviation of the corresponding short axis to a tool load value defined by Equation (10) below.

... 수학식 (10)

... Equation (10)

(However, in Equation (10), α is the ratio of the standard deviation of _{the corresponding minor axis, σ n} is the standard deviation for the steady state acceleration data of the _{corresponding minor axis, and σ f} is the standard for the acceleration data in the abnormal state of the corresponding minor axis. Deviation)

In the present invention as described above, a new method of calculating a tool load value for diagnosing an abnormality in a tool can be provided, and a method for diagnosing an abnormality in a rotating body for diagnosing an abnormality in a rotating body can be provided by using this method.

1 is a perspective view showing a general multi-axis processing machine.
2A is a schematic block diagram illustrating a system for diagnosing an abnormality in a rotating body according to the present invention.
2B is a block diagram showing the configuration of a signal processing module according to the present invention.
3A is a diagram illustrating an example of a Kurtosis graph by a statistical processing module.
3B is a diagram illustrating an example of a mean graph of vibrational displacements of acceleration data by a statistical processing module.
4 is a flowchart showing a method of calculating a tool load value according to the present invention.
5A is an example showing acceleration data in a normal state, and FIG. 5B is an example showing acceleration data in an abnormal state.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms different from each other, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the invention is only defined by the scope of the claims.

With reference to the accompanying drawings below will be described in detail for the implementation of the present invention. Regardless of the drawings, the same reference numerals refer to the same elements, and "and/or" includes each and all combinations of one or more of the recited items.

Although the first, second, and the like are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are only used to distinguish one component from another component. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical idea of the present invention.

The terms used in the present specification are for describing exemplary embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used herein, “comprises” and/or “comprising” do not exclude the presence or addition of one or more other elements other than the mentioned elements.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used with meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

Spatially relative terms "below", "beneath", "lower", "above", "upper", etc. It can be used to easily describe the correlation between a component and other components. Spatially relative terms should be understood as terms including different directions of components during use or operation in addition to the directions shown in the drawings. For example, if a component shown in a drawing is turned over, a component described as "below" or "beneath" of another component will be placed "above" the other component. I can. Accordingly, the exemplary term “below” may include both directions below and above. Components may be oriented in other directions, and thus spatially relative terms may be interpreted according to the orientation.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing a general multi-axis processing machine.

First, as shown in Figure 1, a general multi-axis processing machine, for example, a 5-axis processing machine 100 includes a T-bed 110, the T-bed 110 is a first direction bed (110a) And a second direction bed 110b disposed in a vertical direction with the first direction bed 110b.

In addition, the general 5-axis processing machine 100 includes an X-base 120 disposed above the first direction bed 110a of the T-bed 110, and the X-base 120, wherein the It includes an X-axis rail 121 disposed on the top of the X-base 120.

In this case, the X-axis rail 121 includes an X-axis first rail 121a and an X-axis second rail 121b disposed in parallel with the X-axis first rail 121a.

Meanwhile, for convenience of explanation, the first X-axis rail 121a will be defined as a front rail, and the second X-axis rail 121b will be defined as a back rail.

Subsequently, referring to FIG. 1, a general 5-axis processing machine 100 includes a table 130 disposed on the X-axis rail 121, and the table 130 is a support plate 131 for positioning an object to be processed. ).

In this case, the table 130 is disposed on the X-axis rail 121 and may move in the X-axis direction.

In addition, the general 5-axis processing machine 100 includes a column 140 disposed above the second direction bed 110b of the T-bed 110, and at this time, the Y-axis at the bottom of the column 140 Includes a rail 111.

In this case, the Y-axis rail 111 includes a Y-axis first rail (not shown) and a Y-axis second rail 111b disposed parallel to the Y-axis first rail (not shown).

However, for convenience of explanation, the Y-axis first rail (not shown) is defined as a left rail, and the Y-axis second rail 111b is defined as a right rail.

Meanwhile, in the above, it has been described that the column 140 includes a Y-axis rail 111 in the lower portion of the column 140, but the Y-axis rail 111 is an upper portion of the second direction bed 110b of the T-bed 110. And the column 140 is disposed on the Y-axis rail 111.

In this case, the column 140 is disposed on the Y-axis rail 111 and may move in the Y-axis direction.

In addition, as shown in FIG. 1, a Z-axis rail 141 is included in a certain area of the side surface of the column 140.

In this case, the Z-axis rail 141 includes a Z-axis first rail 141a and a Z-axis second rail 141b disposed parallel to the Z-axis first rail 141a.

Continuing, referring to FIG. 1, a general 5-axis processing machine 100 includes a spindle 150 disposed on the Z-axis rail 141 of the column 140, wherein the spindle 150 is Z It can be moved in the axial direction.

In addition, the 5-axis processing machine includes a tool, and the tool rotates while being mounted on the spindle 150 to perform cutting processing on the work piece.

In this case, the tool may be an end mill, a milling tool, a drill tool, or a boring tool, but the type of the tool is not limited in the present invention.

On the other hand, as described above, in the case of a spindle to which a tool is fastened in a multi-axis processing machine, if an abnormality occurs, it may cause enormous economic loss or personal injury.

Such an abnormality may occur excessively during continuous use of the spindle, even though the life of the spindle has ended, and therefore, it is necessary to diagnose the life of the spindle in advance and replace or repair it periodically.

That is, as described above, in general, in the case of a rotating machine, an abnormality occurs due to various causes, and when such an abnormality occurs, manufacturing defects are caused or damage to the corresponding machine is caused, so that rapid maintenance is required.

In particular, in the case of machine tools, high speed and high precision are being made to improve machining productivity and quality, so it will be more necessary to maintain the optimum state and target accuracy of machine tools and products.If cost reduction is considered, the life of the rotating body (eg, spindle) There is a great demand for diagnostic technology.

Hereinafter, a method for calculating a tool load value according to the present invention and a method for diagnosing an abnormality in a rotating body using the same will be described.

2A is a schematic block diagram illustrating a system for diagnosing an abnormality in a rotating body according to the present invention.

Referring to FIG. 2A, the rotational body abnormality diagnosis system 200 according to the present invention includes a measurement device 210 provided in a certain area of a rotation body to be diagnosed for life, and a measurement output from the measurement device 210. A signal processing module 220 that performs signal processing of data and a signal analysis module 230 that provides schedule information based on measurement data may be included.

The measuring device 210 may measure and transmit acceleration data from the vibration of the rotating body.

For example, the measuring device 210 may include an acceleration sensor 211 and a data logger.

At this time, in the case of the acceleration sensor 211, if the outputted analog data is transmitted to a remote data logger, it may be affected by external noise, so by configuring it as a digital output type, the influence of external noise can be minimized. This is desirable.

In addition, the acceleration sensor 211 is a semiconductor type MEMS (Micro Electro Mechanical System) that can be integrated with a CMOS circuit and has excellent low power consumption, temperature characteristics, and DC characteristics; Microelectronic control technology) Acceleration is measured by applying an acceleration sensor, and this MEMS acceleration sensor may be composed of a three-axis acceleration sensor capable of simultaneously measuring 2 horizontal components and 1 vertical component. A differential output method that removes noise that may be induced by can be used.

The data logger may transmit acceleration data measured by the acceleration sensor 211 to the signal processing module 220 according to a defined communication protocol.

The signal processing module 220 receives acceleration data transmitted from the measurement device 110, analyzes the input acceleration data, and analyzes the input acceleration data to pass and output only components of a required frequency band. Signal processing such as sampling and noise reduction can be performed.

The signal analysis module 230 may provide various monitoring information by performing analysis through an analysis algorithm using acceleration data signal-processed by the measuring device 210 or the signal processing module 220.

For example, the signal analysis module 230 may express PGA (Peak Ground Acceleration) of acceleration data, MMA (Min, Max, Avg) data, power spectrum, response spectrum (acceleration, speed, displacement response spectrum display), etc. It can be configured to perform an analysis function.

The signal analysis module 230 may select an analysis target time point or target period according to a request command input from the outside, provides analysis data for the selected time point or period, and provides the analysis data of the target spindle based on the analysis data. Vibration evaluation can be performed.

2B is a block diagram showing the configuration of a signal processing module according to the present invention.

2B, the signal processing module 220 performs data processing including filtering and sampling of the data prior to analyzing the vibration acceleration data received from the measuring device 210. can do.

More specifically, the signal processing module 220 may include a filtering unit 221 and a sampling unit 222.

The filtering unit 221 may apply a digital filter, and the digital filter removes an unwanted frequency band based on the analysis result by performing a Fast Fourier Transform (FFT) when an input signal (acceleration data) is input. Only components of the desired frequency band can be passed and output.

For example, the filtering unit 221 may use any one of LPF (Low Pas Filtering), HPF (High Pass Filtering), and BPF (Band Width Pass Filtering). You can improve the quality.

The sampling unit 222 may perform sampling on an input signal (acceleration data).

Sampling in signal processing means extracting analog data as digital data.

At this time, the signal analysis module 230 may be configured to analyze the dynamic characteristics of the object by analyzing the maximum amplitude and the natural period from the amplitude of the vibration signal of the rotating body, and to calculate the response spectrum and compare it with the design spectrum. In addition, it may be configured to calculate a vibration velocity from the acceleration data and also calculate the vibration displacement and the cumulative absolute velocity.

Meanwhile, although not shown in the drawing, the signal analysis module 230 is provided with an output interface for outputting the analyzed information, and is connected to a display device to provide the analyzed information as an image including a graph or figure to the user. can do.

Subsequently, referring to FIG. 2A, the rotational body abnormality diagnosis system 200 according to the present invention includes a statistics processing module 240 that processes data transmitted from the signal processing module 220 to perform statistical processing. .

That is, the statistics processing module 240 may perform statistical processing of the collected data according to a preset period and update the statistics database.

At this time, the setting period of the statistics processing module 240 may be selectively designated by the user. For example, it is set in minutes, hours, days, weeks, etc., and statistically processed according to the setting period. Information can be provided.

On the other hand, the statistical data provided by the statistical processing module 240 is processed data transmitted from the signal processing module 220, as described above, and the average data of the vibration displacement for the acceleration data, the standard deviation, and the kurtosis (Kurtosis) may be at least one or more.

3A is a diagram illustrating an example of a Kurtosis graph by a statistical processing module.

The kurtosis shown in FIG. 3A represents the degree to which acceleration data collected from the acceleration sensor 211 for a certain period of time is concentrated around the arithmetic mean, and in general, the statistics processing module 240 calculates the kurtosis by Equation 1 below. can do.

[Equation 1]

However, in Equation 1, K is the kurtosis, X is the signal value, n is the number of samples of the signal, μ is the average of the signal values, and σ is the standard deviation of the signal value (for all samples collected by the acceleration sensor for a certain period of time). Can be defined as

3B is a diagram illustrating an example of a mean graph of vibrational displacements of acceleration data by a statistical processing module.

The average of the acceleration data may be calculated by deriving an average value of the vibration displacement for the acceleration data of all samples collected by the acceleration sensor for a certain period of time.

As described above, in general, the statistics processing module 240 may calculate the kurtosis according to Equation 1 above.

In addition, an abnormality of the rotating body may be diagnosed through the kurtosis value according to Equation 1 described above.

However, in diagnosing an abnormality of a rotating body through the kurtosis value calculated by the general method as described above, the accuracy is low, and although an abnormality has occurred in the rotating body, it is not possible to diagnose this abnormality.

Accordingly, an object of the present invention is to provide a new method of calculating a tool load value for diagnosing an abnormality in a tool, and to provide a system for diagnosing an abnormality in a rotating body by using the method.

4 is a flowchart showing a method of calculating a tool load value according to the present invention.

Referring to FIG. 4, the method of calculating a tool load value according to the present invention includes measuring acceleration data in a steady state and acceleration data in an abnormal state for each axis (S100).

At this time, the general tool is driven in the three-axis directions, that is, the x-axis, the y-axis and the z-axis, and thus, in the present invention, the step of measuring acceleration data in a steady state and acceleration data in an abnormal state for each axis is , acceleration data in a normal state and acceleration data in an abnormal state for each of the x-axis, y-axis, and z-axis directions may be measured.

5A is an example showing acceleration data in a normal state, and FIG. 5B is an example showing acceleration data in an abnormal state.

The steady-state acceleration data indicates a standard in a state in which no abnormality has occurred in the rotating body as described above, and as shown in FIG. 5A, the acceleration data in the steady state indicates that the peak of the signal value is You can see that it is constant.

In addition, the acceleration data in the abnormal state corresponds to the actual acceleration data of the rotating body currently being driven, and as shown in FIG. 5B, the acceleration data in the abnormal state can confirm that the peak of the signal value is unstable. .

Of course, the actual acceleration data of the rotating body currently being driven may represent a signal value similar to the acceleration data in the steady state as in FIG. 5A described above.

In this case, it may be determined that no load has occurred on the tool through the value obtained by calculating the tool load value to be described later. However, the actual acceleration data of the currently driven rotating body is unstable as in FIG. 5B described above. If the signal value is indicated, it may be determined that no load has occurred on the tool through a value obtained by calculating a tool load value to be described later.

That is, the method for calculating the tool load value according to the present invention is in a state in which it is not possible to determine whether the actual acceleration data of the currently driven rotating body is in a normal state or an abnormal state, through the actual acceleration data of the currently driven rotating body. , A tool load value to be described later is calculated, and normal/abnormal of the rotating body may be determined through the tool load value.

In this situation, since the object of the present invention is to calculate a tool load value when a tool load occurs, it is defined as measuring acceleration data in an abnormal state in step S100.

That is, the term "abnormal state" acceleration data is a term defined to distinguish it from the reference "normal state" acceleration data, and the acceleration data of the "abnormal state" calculates the tool load value according to the present invention. For this purpose, it can be determined by actual acceleration data of the currently driven rotating body.

Next, the method of calculating a tool load value according to the present invention includes calculating a ratio of a standard deviation for acceleration data in a steady state and a standard deviation for acceleration data in an abnormal state for each axis (S110). ).

For convenience of explanation, the standard deviation of acceleration data in a steady state is defined as "normal standard deviation", and the standard deviation of acceleration data in an abnormal state is defined as "ideal standard deviation".

On the other hand, as described above, the acceleration data in the steady state presents a standard in a state in which no abnormality has occurred in the rotating body. Therefore, the standard deviation of the acceleration data in the steady state, that is, the normal standard deviation is Corresponds to the measured value.

At this time, as described above, the general tool is driven in the three-axis directions, that is, the x-axis, the y-axis, and the z-axis, and thus, in the present invention, calculating the ratio of the normal standard deviation and the ideal standard deviation is x It is possible to measure the respective ratios for the axis, y axis and z axis directions.

That is, in the present invention, the ratio of the standard deviation of the normal state of the x-axis and the standard deviation of the abnormal state (hereinafter referred to as "the ratio of the standard deviation of the x-axis"), the ratio of the standard deviation of the normal state of the y-axis and the standard deviation of the abnormal state (Hereinafter referred to as "the ratio of the standard deviation of the y-axis") and the ratio of the standard deviation of the normal state of the z-axis and the standard deviation of the abnormal state (hereinafter referred to as "ratio of the standard deviation of the z-axis") can be calculated. Each of these can be defined by the following equations (1) to (3).

... 수학식 (1)

... Equation (1)

(However, in Equation (1), α _x is the ratio of the standard deviation of the x-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _x,n is the normal standard deviation of the x-axis, σ _x,f Is the ideal standard deviation of the x-axis)

... 수학식 (2)

... Equation (2)

(However, in Equation (2), α _y is the ratio of the standard deviation of the y-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _y,n is the normal standard deviation of the y-axis, σ _y,f Is the ideal standard deviation of the y-axis)

... 수학식 (3)

... Equation (3)

(However, in Equation (3), α _z is the ratio of the standard deviation of the z-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _z,n is the normal standard deviation of the z-axis, σ _z,f Is the ideal standard deviation of the z-axis)

Next, the method of calculating a tool load value according to the present invention includes calculating a tool load value for each axis through the ratio of the standard deviation (S120).

As described above, a general tool is driven in three directions, that is, the x-axis, y-axis and z-axis, and in the present invention, calculating the ratio of the normal standard deviation and the ideal standard deviation is the X-axis, Y-axis And each ratio with respect to the Z-axis direction can be measured.

Accordingly, the tool load value according to the present invention can measure the tool load value for each of the x-axis, y-axis and z-axis, that is, the tool load value of the x-axis, the tool load value of the y-axis, and the tool load value of the z-axis. It can be calculated, and these can be defined by the following equations (4) to (6), respectively.

... 수학식 (4)

... Equation (4)

(However, in Equation (4), F _x is the tool load value of the x-axis, α _x is the ratio of the standard deviation of the x-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _x is the acceleration data of the abnormal state of the x axis, μ _x,f is the average of the acceleration data of the abnormal state of the x axis, and σ _x,f is the standard deviation of the acceleration data of the abnormal state of the x axis)

... 수학식 (5)

... Equation (5)

(However, in Equation (5), F _y is the tool load value of the y-axis, α _y is the ratio of the standard deviation of the y-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _y is the acceleration data of the abnormal state of the y-axis, μ _y,f is the average of the acceleration data of the abnormal state of the y-axis, and σ _y,f is the standard deviation of the acceleration data of the abnormal state of the y-axis)

... 수학식 (6)

... Equation (6)

(However, in Equation (6), F _z is the tool load value of the z-axis, α _z is the ratio of the standard deviation of the z-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _z is the acceleration data of the abnormal state of the z axis, μ _z,f is the average of the acceleration data of the abnormal state of the z axis, σ _z,f is the standard deviation of the acceleration data of the abnormal state of the z axis)

Next, the method of calculating the tool load value according to the present invention includes calculating the total tool load value through the tool load value for each axis (S130).

As described above, the tool load value according to the present invention can measure the tool load value for each of the x-axis, y-axis, and z-axis, that is, the tool load value of the x-axis, the tool load value of the y-axis, and the tool of the z-axis. The load value can be calculated, and these can be defined by Equations (4) to (6), respectively.

At this time, the total tool load value according to the present invention may be defined by Equation (7) below.

...수학식 (7)

...Equation (7)

(However, in Equation (7), Ft is the total tool load value, F _x is the tool load value on the x-axis, F _y is the tool load value on the y-axis, and F _z is the tool load value on the z-axis)

As described above, in the case of machine tools, high speed and high precision are being made in order to improve processing productivity and quality, so it will be more necessary to maintain the optimum state and target accuracy of machine tools and products, and if cost reduction is considered, a rotating body (e.g., Spindle) abnormality diagnosis technology is in great demand.

Therefore, in the present invention, through the total tool load value as described above, when the total tool load value is more than a certain value, it is determined as an abnormal state of the tool, and when the total tool load value is less than a certain value, the normal state of the tool. It can be judged as. At this time, a certain value can be set according to the needs of the user.

After all, in the present invention, a new method of calculating a tool load value for diagnosing an abnormality of a tool can be provided, and also, an abnormality of a rotating body for diagnosing an abnormality of a rotating body using a new method of calculating a tool load value. A diagnostic method can be provided.

Meanwhile, in the case of the total tool load value as described above, it was calculated by considering all the tool load values for the x-axis, y-axis, and z-axis.

When all the tool load values for the x-axis, y-axis, and z-axis are considered, the accuracy of the numerical value is high, but since all data for each axis must be considered, the amount of data can be enormous.

Accordingly, in the present invention, the abnormal state of the tool can be determined through the tool load value for any one of the x-axis, y-axis, and z-axis.

That is, in the above-described equation (7), when only the tool load value of the x-axis is considered, it corresponds to F _y = 0 and F _z = 0, so the total tool load value according to the present invention is expressed by the following equation (8). Can be defined.

...수학식(8)

...Equation (8)

In addition, in the above-described equation (7), when only the tool load value of the y-axis is considered, it corresponds to F _x = 0 and F _z = 0, so the total tool load value according to the present invention is expressed by the following equation (9). Can be defined.

...수학식(9)

...Equation (9)

In addition, in the above-described equation (7), when only the tool load value of the z-axis is considered, it corresponds to F _x = 0 and F _y = 0, so the total tool load value according to the present invention is expressed by the following equation (10). Can be defined.

...수학식 (10)

...Equation (10)

That is, if the tool load value of Equation (7) described above is a value considering the tool load in the three-axis direction, the Equations (8) to (10) correspond to values considering the tool load in the short axis direction. .

When referring to the above, the tool load value in the case of considering the tool load in the short axis direction can be calculated as in Equation (10) below, and in this case, the short axis direction may be an x-axis, a y-axis, or a z-axis. have.

...수학식(11)

...Equation (11)

(However, in Equation (11), F is the tool load value in the minor axis direction, α is the ratio of the standard deviation of the minor axis, X is the acceleration data _{of the abnormal state of the corresponding minor axis, and μ f} is the abnormal state of the corresponding minor axis. The average of the acceleration data, σ _f is the standard deviation of the acceleration data in the abnormal state of the short axis)

In addition, the ratio α of the standard deviation of the corresponding short axis in Equation (11) may be defined as in Equation (11) below.

... 수학식 (12)

... Equation (12)

(However, in Equation (12), α is the ratio of the standard deviation of _{the corresponding short axis, σ n} is the normal standard deviation _{of the corresponding short axis, and σ f} is the ideal standard deviation of the corresponding short axis)

Accordingly, referring to FIG. 4 and the related description, the method of calculating the tool load value in the short axis direction according to the present invention is summarized, the steps of measuring acceleration data in a normal state and acceleration data in an abnormal state for the short axis. ; Calculating a ratio of a standard deviation for acceleration data in a normal state and a standard deviation for acceleration data in an abnormal state for the short axis; And calculating the tool load value for the short axis through the ratio of the standard deviation.

In this case, the ratio of the standard deviation to the acceleration data in the steady state and the standard deviation to the acceleration data in the abnormal state may be defined by Equation (11) above, and the ratio of the standard deviation The tool load value calculated through, for the short axis, may be defined by Equation (10) described above.

Meanwhile, as described above, when considering the tool load in the short axis direction, the tool load value may be calculated as in Equation (10), and in this case, the short axis direction may be an x-axis, a y-axis, or a z-axis. .

In this case, among the x-axis, y-axis, and z-axis, which axis to measure the tool load in the short axis direction may be selected as follows.

That is, in determining which axis of the x-axis, y-axis, and z-axis to measure the tool load in the minor axis direction, the ideal standard deviation of one axis is the denominator, and the ideal standard deviation of the other two axes is the numerator, respectively. As a result, a value with a large ideal standard deviation ratio can be selected as a standard for measuring the tool load in the short axis direction.

,

이 큰 값을 단축 방향 공구부하를 측정하는 기준으로 선정할 수 있다.For example, when the ideal standard deviation of each of the x-axis, y-axis and z-axis is σ _x , σ _y , σ _z , respectively, the ideal standard deviation of any one axis, that is, σ _z is the denominator, and the remainder Ideal standard deviation of two axes, that is, σ _x and σ _y as the numerator, the ratio of the ideal standard deviation, that is,

,

This large value can be selected as a criterion for measuring the tool load in the minor axis direction.

의 값이 0.7이고,

의 값이 0.3인 경우, 이상 표준편차의 비율은

의 값이

이 크므로, 단축 방향 공구부하를 측정하는 기준으로 x축을 선정하여, x축과 관련된 값을 단축 방향 공구부하 값으로 선정할 수 있다.E.g,

Is the value of 0.7,

If the value of is 0.3, the ratio of the ideal standard deviation is

The value of

Therefore, it is possible to select the x-axis as a reference for measuring the tool load in the minor axis direction, and select a value related to the x-axis as the tool load value in the minor axis direction.

Accordingly, in the present invention, a method for calculating a tool load value of a new method for diagnosing an abnormality in a tool may be provided, and a method for diagnosing an abnormality in a rotating body using the same can be provided.

Although the embodiments of the present invention have been described with reference to the above and the accompanying drawings, those of ordinary skill in the art to which the present invention pertains can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. You can understand that there is. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects.

Claims (14)

Measuring acceleration data in a normal state and acceleration data in an abnormal state for each axis;
Calculating a ratio of a standard deviation for acceleration data in a steady state and a standard deviation for acceleration data in an abnormal state for each of the axes;
Calculating a tool load value for each axis through the ratio of the standard deviation; And
Including the step of calculating a total tool load value through the tool load value for each of the axes,
Each of the axes includes an x-axis, a y-axis and a z-axis,
For each of the above axes, the ratio of the standard deviation of the acceleration data in the steady state and the standard deviation of the acceleration data in the abnormal state is the ratio of the standard deviation of the x-axis, which is the ratio of the standard deviation of the steady state of the x-axis and the standard deviation of the abnormal state. , the ratio of the standard deviation of the y-axis, which is the ratio of the standard deviation of the normal state of the y-axis and the standard deviation of the abnormal state, and the ratio of the standard deviation of the z-axis, which is the ratio of the standard deviation of the normal state and the standard deviation of the z-axis,
The ratio of the standard deviation of the x-axis is defined by the following Equation (1), the ratio of the standard deviation of the y-axis is defined by the following Equation (2), and the ratio of the standard deviation of the z-axis is the following Equation (3) Is defined as,
For each of the axes, the tool load value includes a tool load value of the x-axis, a tool load value of the y-axis, and a tool load value of the z-axis,
The x-axis tool load value is defined by the following equation (4), the y-axis tool load value is defined by the following equation (5), and the z-axis tool load value is defined by the following equation (6). How to calculate the tool load value.

... Equation (1)
(However, in Equation (1), α _x is the ratio of the standard deviation of the x-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _x,n is the normal standard deviation of the x-axis, σ _x,f Is the ideal standard deviation of the x-axis)

... Equation (2)
(However, in Equation (2), α _y is the ratio of the standard deviation of the y-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _y,n is the normal standard deviation of the y-axis, σ _y,f Is the ideal standard deviation of the y-axis)

... Equation (3)
(However, in Equation (3), α _z is the ratio of the standard deviation of the z-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _z,n is the normal standard deviation of the z-axis, σ _z,f Is the ideal standard deviation of the z-axis)

... Equation (4)
(However, in Equation (4), F _x is the tool load value of the x-axis, α _x is the ratio of the standard deviation of the x-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _x is the acceleration data of the abnormal state of the x axis, μ _x,f is the average of the acceleration data of the abnormal state of the x axis, and σ _x,f is the standard deviation of the acceleration data of the abnormal state of the x axis)

... Equation (5)
(However, in Equation (5), F _y is the tool load value of the y-axis, α _y is the ratio of the standard deviation of the y-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _y is the acceleration data of the abnormal state of the y-axis, μ _y,f is the average of the acceleration data of the abnormal state of the y-axis, and σ _y,f is the standard deviation of the acceleration data of the abnormal state of the y-axis)

... Equation (6)
(However, in Equation (6), F _z is the tool load value of the z-axis, α _z is the ratio of the standard deviation of the z-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _z is the acceleration data of the abnormal state of the z axis, μ _z,f is the average of the acceleration data of the abnormal state of the z axis, σ _z,f is the standard deviation of the acceleration data of the abnormal state of the z axis) delete delete The method of claim 1,
The total tool load value is a method of calculating a tool load value defined by Equation (7) below.

...Equation (7)
(However, in Equation (7), Ft is the total tool load value, F _x is the tool load value on the x-axis, F _y is the tool load value on the y-axis, and F _z is the tool load value on the z-axis) The method of claim 4,
In Equation (7), when only the tool load value of the x-axis is considered, it _{corresponds to F y} = 0 and F _z = 0, and the total tool load value is defined by Equation (8) below,
In Equation (7), when only the tool load value of the y-axis is considered, it _{corresponds to F x} = 0 and F _z = 0, and the total tool load value is defined by Equation (9) below,
In Equation (7), when only the tool load value of the z-axis is considered, it _{corresponds to F x} = 0 and F _y = 0, and the total tool load value is calculated by the tool load value defined by Equation (10) below. Way.

...Equation (8)

...Equation (9)

...Equation (10) Measuring acceleration data in a normal state and acceleration data in an abnormal state for the short axis;
Calculating a ratio of a standard deviation for acceleration data in a steady state and a standard deviation for acceleration data in an abnormal state for the short axis; And
Comprising the step of calculating a tool load value for the short axis through the ratio of the standard deviation,
The ratio of the standard deviation of the short axis, which is the ratio of the standard deviation of the acceleration data in the steady state and the standard deviation of the acceleration data in the abnormal state, with respect to the short axis, is defined by the following equation (12),
The tool load value calculated through the ratio of the standard deviation, for the short axis, is defined by Equation (11) below.

... Equation (12)
(However, in Equation (12), α is the ratio of the standard deviation of _{the corresponding minor axis, σ n} is the standard deviation for the steady state acceleration data of the _{corresponding minor axis, and σ f} is the standard for the acceleration data in the abnormal state of the corresponding minor axis. Deviation)

...Equation (11)
(However, in Equation (11), F is the tool load value in the minor axis direction, α is the ratio of the standard deviation of the minor axis, X is the acceleration data _{of the abnormal state of the corresponding minor axis, and μ f} is the abnormal state of the corresponding minor axis. The average of the acceleration data, σ _f is the standard deviation of the acceleration data in the abnormal state of the short axis) delete delete The method of claim 6,
The short axis is the x-axis, y-axis, or z-axis,
A criterion for selecting which axis of the x-axis, y-axis, and z-axis to calculate the tool load value is,
The standard deviation of the acceleration data in the abnormal state of any one of the x-axis, the y-axis, and the z-axis is used as the denominator, and the standard deviation of the acceleration data in the abnormal state of the other two axes is used as a numerator. A method of calculating a tool load value in which a deviation ratio is calculated and a value having a large ideal standard deviation ratio is selected as a criterion for calculating a tool load value. In the method of calculating the total tool load value,
The method of calculating the total tool load value is calculated by the following equation (7),
The tool load value of the x-axis is defined by Equation (4) below, the tool load value of the y-axis is defined by Equation (5) below, and the tool load value of the z-axis is the total tool load defined by Equation (6) below. How to calculate the value.

...Equation (7)
(However, in Equation (7), Ft is the total tool load value, F _x is the tool load value on the x-axis, F _y is the tool load value on the y-axis, and F _z is the tool load value on the z-axis)

... Equation (4)
(However, in Equation (4), F _x is the tool load value of the x-axis, α _x is the ratio of the standard deviation of the x-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _x is the acceleration data of the abnormal state of the x axis, μ _x,f is the average of the acceleration data of the abnormal state of the x axis, and σ _x,f is the standard deviation of the acceleration data of the abnormal state of the x axis)

... Equation (5)
(However, in Equation (5), F _y is the tool load value of the y-axis, α _y is the ratio of the standard deviation of the y-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _y is the acceleration data of the abnormal state of the y-axis, μ _y,f is the average of the acceleration data of the abnormal state of the y-axis, and σ _y,f is the standard deviation of the acceleration data of the abnormal state of the y-axis)

... Equation (6)
(However, in Equation (6), F _z is the tool load value of the z-axis, α _z is the ratio of the standard deviation of the z-axis, X is the acceleration data, μ is the average of the acceleration data, and σ is the standard deviation of the acceleration data. , X _z is the acceleration data of the abnormal state of the z axis, μ _z,f is the average of the acceleration data of the abnormal state of the z axis, σ _z,f is the standard deviation of the acceleration data of the abnormal state of the z axis) delete The method of claim 10,
The ratio of the standard deviation of the x-axis is defined by the following Equation (1), the ratio of the standard deviation of the y-axis is defined by the following Equation (2), and the ratio of the standard deviation of the z-axis is the following Equation (3) The method of calculating the total tool load value defined as.

... Equation (1)
(However, in Equation (1), α _x is the ratio of the standard deviation of the x-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _x,n is the normal standard deviation of the x-axis, σ _x,f Is the ideal standard deviation of the x-axis)

... Equation (2)
(However, in Equation (2), α _y is the ratio of the standard deviation of the y-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _y,n is the normal standard deviation of the y-axis, σ _y,f Is the ideal standard deviation of the y-axis)

... Equation (3)
(However, in Equation (3), α _z is the ratio of the standard deviation of the z-axis, σ _n is the normal standard deviation, σ _f is the ideal standard deviation, σ _z,n is the normal standard deviation of the z-axis, σ _z,f Is the ideal standard deviation of the z-axis) A method of calculating a tool load value calculated according to Equation (11) below.

...Equation (11)
(However, in Equation (11), F is the tool load value in the minor axis direction, α is the ratio of the standard deviation of the minor axis, X is the acceleration data _{of the abnormal state of the corresponding minor axis, and μ f} is the abnormal state of the corresponding minor axis. The average of the acceleration data, σ _f is the standard deviation of the acceleration data in the abnormal state of the short axis) The method of claim 13,
The ratio of the standard deviation of the corresponding short axis is a method of calculating a tool load value defined by Equation (12) below.

... Equation (12)
(However, in Equation (12), α is the ratio of the standard deviation of _{the corresponding minor axis, σ n} is the standard deviation for the steady state acceleration data of the _{corresponding minor axis, and σ f} is the standard for the acceleration data in the abnormal state of the corresponding minor axis. Deviation)

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