KR20170004406A - Apparatus for detecting and suppressing resonance in servo system using a plurality of fixed notch filter and method thereof - Google Patents

Abstract

The present invention relates to an apparatus to detect and suppress resonance in a servo system and a method thereof. The apparatus according to an embodiment of the present invention comprises: a resonance detector which detects generation, suppression, and magnitude of the resonance; a frequency estimator which estimates a frequency of the resonance generated from a current command in real time; a fixed notch filter unit which filters the current command to suppress a previously known first resonance; a resonance comparator which compares the magnitude of a second resonance with the magnitude of the first resonance when the second resonance is detected while the fixed notch filter unit is used; and a filter setting device which changes the notch frequency of the fixed notch filter unit into the frequency of the second resonance to suppress the second resonance when the magnitude of the second resonance is greater than that of the first resonance.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus and method for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters,

The present invention relates to an apparatus and method for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters, and more particularly, to a system and method for detecting and suppressing resonance in a servo system using a resonance detector, The present invention relates to a method for automatically detecting a plurality of generated resonances, estimating the resonance frequency thereof, and suppressing resonance according to the resonance amplitude.

Conventionally, a method of applying a notch filter to an output current command as a method for suppressing a resonance phenomenon of a servo system has been widely used. A notch filter is a filter that removes a component of a specific frequency band from an input signal. If a notch filter is used, the resonance influence of the servo system can be suppressed by removing frequency components causing resonance in the current command.

1 is a block diagram of a servo system according to the prior art. Referring to FIG. 1, a conventional servo system 1 includes a control unit 10 and a plant 20. The control unit 10 includes a servo controller 11, a fixed notch filter 12, and a current controller 13. The plant 20 includes a motor 21, a load 22 and an encoder 23. The servo controller 11 generates a current command for controlling the motor 21 of the plant 20. When the current command is transmitted from the servo controller 11, the current controller 13 provides the motor 21 with a drive current corresponding to the current command. The encoder 23 measures the rotation angle or rotation speed of the motor 21 driven in the plant 20 and provides the result to the servo controller 11 as feedback. Then, the servo controller 11 controls the motor 21 by referring to the received feedback.

Here, the fixed notch filter 12 removes a component corresponding to the notch frequency in the current command output from the servo controller 11. If the notch frequency of the fixed notch filter 12 is set to the resonance frequency when the resonance frequency of the servo system 1 including the plant 20 is known, the resonance frequency component of the output current command of the servo controller 11 And the drive current output from the current controller 13 does not cause the resonance phenomenon of the motor 21. [

However, such a resonance suppression method can be realized only when the resonance frequency of the system is known in advance, and when a new resonance is generated while the presently provided notch filter is in operation, resonance of a new resonance frequency can not be processed.

To solve this problem, there is a method of using a plurality of notch filters. However, even when a plurality of notch filters are used, the resonance frequencies must be known in advance, and when a plurality of notch filters are in use, new resonance occurs.

US Patent No. 6,507,165 Japanese Patent Application Publication JP2009-296746 A2

It is an object of the present invention to provide an apparatus and method for efficiently detecting and suppressing resonance occurring in a servo system, and efficiently operating a plurality of fixed notch filters.

An apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention includes a resonance detector for detecting resonance occurrence and suppression of a servo system from a current command generated in a servo controller, A frequency estimator for estimating a resonance frequency generated from the current command in real time, a fixed notch filter for filtering the current command to suppress a known first resonance, a second notch filter unit for detecting a second resonance A resonance comparator for comparing the magnitude of the second resonance with the magnitude of the first resonance and a resonance comparator for comparing the magnitude of the second resonance with the magnitude of the first resonance, And a filter setter for changing the notch frequency to the frequency of the second resonance.

The apparatus may further include a resonance detector for detecting and suppressing a resonance of the servo system using a plurality of fixed notch filters according to an embodiment of the present invention, Generation and suppression, and the magnitude of the generated resonance.

Also, in the apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment, the resonance comparator may store the size of the first resonance or the second resonance in a memory.

Further, in the apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment, when there are a plurality of known first resonances and the fixed notch filter unit includes a plurality of fixed notch filters, The plurality of fixed notch filters may each have a different notch frequency to suppress a plurality of first resonances.

Further, in an apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment, when the second resonance is detected while all the fixed notch filters in the fixed notch filter unit are in use, The size of the first resonance suppressed by the fixed notch filter unit may be compared with each other, and then the size of the smallest resonance and the size of the second resonance may be compared.

Further, in an apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment, when the magnitude of the second resonance is larger than the smallest resonance of the first resonance, The notch frequency of the fixed notch filter suppressing the smallest resonance may be changed to the second resonant frequency so that the second resonance is suppressed.

The apparatus may further include an adaptive notch filter for filtering the current command by using a frequency estimated by the frequency estimator as a notch frequency in the servo system resonance detection and suppression apparatus using a plurality of fixed notch filters according to an embodiment .

Further, in an apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment, the filter setter may further include a filter setting unit that, when the suppression of the second resonance is detected by the resonance sensor after filtering of the adaptive notch filter unit , The notch frequency of the adaptive notch filter unit may be regarded as the second resonance frequency.

The apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention is characterized in that the filter setting unit sets the notch frequency of the fixed notch filter for suppressing the smallest resonance in the fixed notch filter unit, After setting the notch frequency of the notch filter, the operation of the adaptive notch filter can be stopped.

A method of detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention includes a first step of filtering a current command using a fixed notch filter unit to suppress a first resonance previously known in a servo controller, Detecting a resonance frequency of the servo system from the current command, detecting a magnitude of the generated resonance, estimating a resonance frequency generated from the current command in real time, detecting a second resonance when the second resonance is detected, Comparing the magnitude of the second resonance with the magnitude of the first resonance, and, when the magnitude of the second resonance is larger than the magnitude of the first resonance, 2 resonant frequency.

In the method of detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention, the step of detecting occurrence and suppression of resonance of the servo system from the current command, A magnitude variation of the magnitude of the current command, or a probabilistic analysis value for the current command.

The apparatus may further include a step of storing the size of the first resonance or the second resonance in a memory, in the apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an exemplary embodiment.

In the apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention, the first resonance may be a plurality of previously known resonances, and the first filtering may include suppressing the plurality of first resonances A fixed notch filter unit including a plurality of fixed notch filters having different notch frequencies may be used.

In the apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment, if a second resonance is detected while all the fixed notch filters in the fixed notch filter unit are in use, And comparing the magnitude of the first resonance of the first resonator with the magnitude of the second resonance of the first resonator.

In the apparatus for suppressing and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment, the step of changing the notch frequency of the fixed notch filter unit such that the second resonance is suppressed may include: Changing the notch frequency of the fixed notch filter suppressing the smallest resonance to the second resonant frequency so that the second resonance is suppressed when the size of the notch filter is larger than the size of the smallest resonance.

[0027] In another aspect of the present invention, there is provided an apparatus for detecting and suppressing a resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention, wherein when the second resonance is detected in a state where the first resonance is suppressed, And a second filtering step of filtering the current command using a notch filter.

The apparatus may further include a plurality of fixed notch filters, wherein the notch frequency of the adaptive notch filter is set to a predetermined value when the suppression of the second resonance is detected after the filtering of the adaptive notch filter, The second resonant frequency may be regarded as a second resonant frequency.

The apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention is characterized in that the filter setter is configured to adjust the notch frequency of the fixed notch filter in the fixed notch filter unit to the notch frequency of the adaptive notch filter unit And stopping the operation of the adaptive notch filter.

According to embodiments of the present invention, it is possible to estimate and suppress, in real time, resonance occurring when a resonance phenomenon occurs in a servo system in which resonance information is not known.

Also, since the resonance suppression function is performed using the fixed notch filter, it is possible to suppress a plurality of resonance components as many as the number of fixed notch filters that can be operated by the servo system.

In addition, since the fixed notch filter is reset in consideration of the magnitude of the resonance generated when the servo system detects a larger number of resonances than the number of fixed notch filters that can be operated, a limited number of fixed notch filters necessary for resonance suppression can be efficiently used .

1 is a block diagram of a servo system according to the prior art.
2 is a block diagram of a servo system according to an embodiment of the present invention.
3A and 3B are block diagrams showing an example of a filter unit 120 according to an embodiment of the present invention.
4 is a flowchart illustrating a method of detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention.
5 is a flowchart illustrating a method of detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to another embodiment of the present invention.

This patent application was developed with the support of R & D program of Ministry of Commerce, Industry and Energy [10045630, Development of high-performance servo system with tuning function without tuning].

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of example, specific embodiments in which the invention may be practiced. Embodiments of the detailed description are provided to those skilled in the art for the purpose of disclosing the detailed description for carrying out the invention.

Each of the embodiments of the present invention can describe different cases, but it does not mean that the embodiments are mutually exclusive. For example, the specific shapes, structures, and characteristics described in connection with one embodiment of the detailed description may be implemented in other embodiments without departing from the spirit and scope of the present invention. It is also to be understood that the location or arrangement of the individual components of the embodiments disclosed herein may be varied without departing from the spirit and scope of the invention.

On the other hand, in various embodiments, the same or similar reference numerals refer to the same or similar components. In the accompanying drawings, the sizes of the respective components may be exaggerated for explanatory purposes and need not be equal to or similar to the actual applied size.

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

2 is a block diagram of a servo system according to an embodiment of the present invention. 2, a servo system 1000 according to an embodiment of the present invention may include a resonance suppression unit 100, a controller 200, and a plant 300. The controller 200 may include a servo controller 210 and a current controller 220. The servo controller 210 and the current controller 220 may perform the same functions as those of the servo controller 11 and the current controller 13 described with reference to FIG. That is, the servo controller 210 generates a current command, and the current controller 220 can generate a drive current according to a current command.

The plant 300 may include a motor 310, a load 320 and an encoder 330. The function of each component is the same as that of the motor 21, the load 22, and the encoder 23, ≪ / RTI >

The resonance suppression unit 100 may include a resonance detector 110, a frequency estimator 150, a filter unit 120, a resonance comparator 130, and a filter configurer 140. The filter unit 120 may include one or more fixed notch filters or one or more adaptive notch filters.

The components of the resonance suppressing unit 100 described above may be partially or wholly hardware or software.

The apparatus for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention includes a resonance detector 110, a frequency estimator 150, a filter unit 120 including a fixed notch filter unit, (130), and a filter configurer (140).

The resonance detector 110 receives the current command generated from the servo controller 210 as an input signal, and detects the resonance generation and resonance suppression of the servo system from the current command and the magnitude of the generated resonance. That is, the resonance detector 110 can detect whether resonance occurs in the plant 300 or not based on the current command generated in response to the signal fed back from the encoder 330.

Also, the resonance sensor 110 can measure the magnitude of the resonance generated when resonance is detected. Also, after the filtering operation of the filter unit 120, the resonance detector 110 can sense whether or not the sensed resonance is effectively suppressed by the filtering.

In order to detect (or measure) the magnitude of the generated resonance, whether resonance is generated and inhibited, and the magnitude of the generated resonance, the resonance sensor 110 may use a magnitude variation of the magnitude of the current command or a probabilistic analysis value for the current command . The probabilistic analysis value may include at least one of an average, a variance, a probability density function, an autocorrelation, a cross-correlation, and an n-th moment for the current command. The resonance sensor 110 may transmit the detection result or the resonance size measurement result to the resonance comparator 130 (path c) or the filter setter 140 (path c ').

The frequency estimator 150 receives the current command and estimates the frequency of the current command in real time. The frequency estimator 150 can continuously estimate the frequency of the input signal using the variation amount of the estimated frequency with respect to the frequency of the input signal at every calculation cycle so that the estimated frequency to be outputted becomes the resonance frequency represented by the current command . For example, the frequency estimator 150 may estimate the frequency of the input signal by integrating the variation of the estimated frequency calculated every cycle.

In one example, the frequency estimator 150 may start frequency estimation when a second resonance is detected.

As the integrated frequency becomes closer to the fundamental frequency of the current command, which is the input signal, the calculated variation amount of the estimated frequency becomes smaller, and the estimated frequency converges to the fundamental frequency of the current command as the input signal. Therefore, the estimated frequency e output from the frequency estimator 150 in the steady state becomes the fundamental frequency of the current command.

The frequency estimator 150 may be designed as an adaptive filter-based frequency estimator expressed by Equation (1).

는 적응형 필터의 감쇄비,

는 추정 주파수,

는 주파수 추정 이득,

는 입력 신호로 본 발명에서는 전류 명령(a)을 나타낸다. 상기 주파수 추정기(150)는 매 단위시간 마다 추정 주파수의 미소 변화량

을 계산하고 이를 적분하여 입력 신호

의 기본 주파수를 추정한다.Where x is the state of the adaptive filter,

The attenuation ratio of the adaptive filter,

Is the estimated frequency,

Is a frequency estimation gain,

(A) in the present invention as an input signal. The frequency estimator 150 estimates the amount of change of the estimated frequency

And integrates them to obtain an input signal

Of the fundamental frequency.

The filter unit 120 may suppress the resonance of the servo system by filtering the current command with respect to a fixed notch frequency. That is, the notch frequencies of the plurality of fixed notch filters held by the fixed notch filter unit of the filter unit 120 may be set to a previously known resonance frequency of the first resonance. The previously known first resonance may be plural.

The resonance comparator 130 may store the magnitude of the first resonance in a memory (not shown).

When the second resonance is detected while all the fixed notch filters in the fixed notch filter portion are being used to suppress the first resonance, a fixed notch filter for suppressing the second resonance is not set The problem that can not be done occurs. In this case, the resonance comparator 130 compares the sizes of the first resonance and the second resonance suppressed by the fixed notch filter unit.

When the magnitude of the second resonance is larger than the magnitude of the first resonance as a result of the comparison of the resonance comparator 130, the filter setter 140 adjusts the notch frequency of the fixed notch filter unit so that the second resonance is suppressed The frequency of the second resonance can be changed.

In addition, when the size of the second resonance is larger than the size of the first resonance as a result of the comparison of the resonance comparator 130, the resonance comparator 130 may store the size of the second resonance.

Also, in one example, a plurality of previously known first resonances may be present. The plurality of fixed notch filters included in the fixed notch filter section may have different notch frequencies to suppress the plurality of first resonances.

In the case where there are a plurality of previously known first resonances, the resonance comparator 130 compares sizes of a plurality of previously known first resonances with each other when the second resonance is sensed by the resonance sensor 110. The resonance comparator 130 determines the smallest resonance among a plurality of previously known first resonances. Thereafter, the resonance comparator 130 can compare the magnitude of the second resonance with the magnitude of the smallest resonance (i.e., the smallest resonance among the first resonances previously known).

As a result of the comparison, when the magnitude of the second resonance is larger than the magnitude of the smallest resonance, the filter setter 140 can change the notch frequency of the fixed notch filter suppressing the smallest resonance to the second resonant frequency.

In the apparatus for detecting and suppressing resonance of a servo system using the plurality of fixed notch filters according to an embodiment of the present invention, the filter unit 120 may include a resonance detector 110 , The frequency estimator 150 estimates the frequency of the second resonance by using the frequency estimated in real time by the frequency estimator 150 as a notch frequency to confirm whether or not the frequency estimator 150 succeeds in frequency estimation of the second resonance, And an adaptive notch filter for filtering the command.

When the second resonance is detected, the filter setter 140 operates the adaptive notch filter to confirm that the frequency estimator 150 successfully estimates the frequency of the second resonance. That is, if the suppression of the second resonance is detected by the resonance sensor 110 after the filtering of the adaptive notch filter set by sensing the second resonance, the filter setter 140 determines that the frequency estimator 150 It is determined that the frequency of the second resonance has been successfully estimated. In this case, the notch frequency of the adaptive notch filter may be regarded as the second resonance frequency.

The filter setter 140 successfully estimates the frequency of the second resonance generated by the frequency estimator 150 through the above operation and if it is confirmed that the second resonance is suppressed, After setting the notch frequency of the notch filter to the notch frequency of the adaptive notch filter, the operation of the adaptive notch filter can be stopped.

The adaptive notch filter may be designed as a second notch filter expressed by Equation (2) below, but the present invention is not limited thereto.

은 노치 주파수,

는 필터의 감쇄비 (damping factor)를 나타낸다. 상기 적응 노치 필터의 노치 주파수인

는 주파수 추정기(120)의 추정 주파수로서 시간에 따라 변할 수 있다.Where s is the Laplace operator,

Notch frequency,

Represents the damping factor of the filter. The notch frequency of the adaptive notch filter

May vary over time as an estimated frequency of the frequency estimator 120. [

3A and 3B are block diagrams showing an example of a filter unit 120 according to an embodiment of the present invention. 3A, the filter unit 120 may include a fixed notch filter unit 121, and the fixed notch filter unit 121 may include one or more fixed notch filters 121a and 121b.

Also, in another embodiment, the filter unit 120 may further include an adaptive notch filter unit 122 as shown in FIG. 3B. The adaptive notch filter unit 122 may include one adaptive notch filter 122a, but the present invention is not limited thereto, and a plurality of adaptive notch filters may be included.

In FIG. 3B, one adaptive notch filter 122a and two fixed notch filters 121a and 121b are shown, but their order and number are only exemplary. In a preferred embodiment of the present invention, however, the adaptive notch filter may be a single number, and the fixed notch filter may be plural.

Here, the adaptive notch filter is a notch filter in which a notch frequency is changed in real time as an estimated frequency of the frequency estimator 150, and a fixed notch filter is a notch filter in which a fixed frequency is a notch frequency.

The fixed notch filter unit 121 may filter the current command to suppress a plurality of previously known first resonances. Here, the first resonance refers to the resonance suppressed by the fixed notch filters 121a and 121b in the fixed notch filter unit.

The notch frequencies of the fixed notch filter 121a and the fixed notch filter 121b of the fixed notch filter unit 121 are set to f11 and f12 in order to suppress the first resonance with the resonance frequencies f11 and f12 Can be. In another example, at least one of the fixed notch filters of the fixed notch filter 121 may be in an empty state in which the notch frequency is not set.

The resonant comparator 130 may be configured to store the respective resonance sizes for the fixed notch filter in which the notch frequency of the fixed notch filter unit is set. That is, in one example, the resonance comparator 13 may be configured to store the magnitudes M1 and M2 of the first resonance having the resonance frequencies f11 and f12, respectively, in the memory.

The resonance comparator 130 compares the magnitude of the new resonance detected by the resonance sensor 110 with the magnitude of the new resonance detected by the resonance comparator 130 based on the sensed information c received from the resonance sensor 110, 1 resonance can be compared. And provide the result to the filter setter 140.

The resonance comparator 130 can compare the magnitude of the first resonance with the magnitude of the second resonance when a new resonance (i.e., second resonance) is sensed while the first resonance is suppressed. Specifically, when the second resonance is detected, the resonance comparator 130 can compare the magnitudes of the plurality of first resonances currently suppressed. It is possible to select the resonance having the smallest size among the first resonances and to compare the size of the smallest resonance and the size of the second resonance among the first resonances. And provide the result to the filter setter 140.

3A, when the size of the first resonance suppressed by the fixed notch filter 121a is M1 and the size of the first resonance suppressed by the fixed notch filter 121b is M2 and M2 is larger than M1 The resonance comparator 130 may compare the magnitude of the second resonance M3 sensed by the resonance sensor 110 with the magnitude of the first resonance M1.

The filter setter 140 may send a signal d to the filter unit 120 to control the operation of the filters in the filter unit 120. The filter setting unit 140 may be configured to set the fixed notch filter unit 121 so that the second resonance is suppressed when the magnitude M3 of the second resonance is larger than the smallest resonance M1 of the first resonance. The notch frequency of the fixed notch filter 121a can be changed. The operation of filter setter 140 described above may be implemented by user input or automated logic.

In the above example, since M2 is assumed to be larger than M1, the filter setter 140 can change the notch frequency of the fixed notch filter 121a to the resonance frequency of the second resonance when M3 is larger than M1.

That is, when the resonance frequency of the second resonance is f21, the filter setter 140 can change the notch frequency of the fixed notch filter 121a from f11 to f21. Accordingly, the largest resonance among the plurality of resonances occurring in the servo system 1000 can be selected and suppressed using a plurality of fixed notch filters that can be operated.

Referring to FIG. 3B, when the second resonance is detected by the resonance sensor 110 in a state where the first resonance is being suppressed, the frequency estimator 120 estimates the frequency of the second resonance And an adaptive notch filter unit 122 for filtering the current command by using a frequency estimated by the frequency estimator as a notch frequency.

The frequency estimator 150 can estimate the frequency of the current command in real time when a second resonance is detected by the resonance sensor 110 in a state where the first resonance is suppressed. And provide the estimated frequency e to the adaptive notch filter unit 122 of the filter unit 120. [

The adaptive notch filter 122a in the adaptive notch filter unit 122 may filter the current command by using the frequency e estimated in real time by the frequency estimator 150 as a notch frequency.

The adaptive notch filter unit 122 may filter the current command a by setting the frequency estimated by the frequency estimator 150 as a notch frequency and provide the filtered current command b to the current controller 220 .

If the suppression of the second resonance is detected by the resonance sensor 110 after filtering the adaptive notch filter unit 122, the frequency estimator 150 may determine that the frequency of the second resonance has been successfully estimated In this case, the notch frequency of the adaptive notch filter 122a may be regarded as the second resonant frequency.

4 is a flowchart illustrating a method of detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to an embodiment of the present invention. The resonance detection and suppression method of the servo system using the plurality of fixed notch filters may be implemented by the elements of the resonance detection and suppression apparatus of the servo system using the plurality of fixed notch filters.

Referring to FIG. 4, a method of detecting and suppressing resonance of a servo system using a plurality of fixed notch filters includes a first filtering step (S100) of filtering the current command using a fixed notch filter unit to suppress a known first resonance, (S200) of generating and suppressing resonance from the current command generated in the servo controller and estimating the magnitude of the generated resonance, estimating the resonance frequency generated from the current command in real time (S300), detecting the second resonance (S400) of comparing the detected second resonance with the magnitude of the first resonance (S400). When the magnitude of the second resonance is larger than the magnitude of the first resonance, And changing the negative notch frequency to the second resonance frequency (S500).

The step S200 of detecting whether the resonance of the servo system is generated or suppressed and the magnitude of the generated resonance from the current command may use a magnitude variation of the current command or a probabilistic analysis value of the current command .

In one embodiment, the step of storing the size of the previously known first resonance or the second resonance in the memory (S600) may be further included.

In this case, the first filtering step (SlOO) may include a fixed notch filter including a plurality of fixed notch filters having different notch frequencies to suppress the plurality of first resonances, And using a notch filter portion.

In one embodiment, the method for detecting and suppressing resonance of a servo system using the plurality of fixed notch filters may include using an adaptive notch filter having a notch frequency as an estimated frequency to check whether the frequency of the second resonance is successfully estimated And a second filtering step of filtering the current command.

When the second resonance is detected while all the fixed notch filters in the fixed notch filter unit are in use, the magnitudes of the plurality of first resonances being suppressed are compared, and the magnitude of the smallest resonance among them is compared with the magnitude of the second resonance And comparing the magnitudes of the first and second magnitudes.

Wherein the step of changing the notch frequency of the fixed notch filter unit such that the second resonance is suppressed may include changing the notch frequency of the fixed notch filter unit so that the second resonance is suppressed when the second resonance is larger than the smallest resonance size And changing the notch frequency of the suppressing notch filter to the second resonance frequency.

Wherein when the second resonance suppression is detected by the resonance sensor after filtering the adaptive notch filter, it is determined that the second resonance frequency has been successfully estimated. In this case, the notch frequency of the adaptive notch filter may be determined as the second resonance frequency .

In one embodiment, when the second resonance is detected in the state where the first resonance is suppressed, the method may further include a second filtering step of filtering the current command using an adaptive notch filter having the estimated frequency as a notch frequency have.

When it is confirmed that the resonance frequency generated by the above method is successfully estimated, the notch frequency of the fixed notch filter in the fixed notch filter unit is set to the notch frequency of the adaptive notch filter, and the operation of the adaptive notch filter is stopped have. If all of the fixed notch filters in the fixed notch filter section are being used for the first resonance suppression, the notch frequency of the fixed notch filter suppressing resonance of the smallest size of the first resonance, It can be changed to the notch frequency of the adaptive notch filter.

5 is a flowchart illustrating a method of detecting and suppressing resonance of a servo system using a plurality of fixed notch filters according to another embodiment of the present invention. Referring to FIG. 5, in a state where a plurality of first resonances are suppressed through the fixed notch filter unit (S10), the generation and the size of a second resonance different from the first resonance are sensed (S20).

If the second resonance is detected, it is determined whether there is a notch filter that does not operate among the currently held fixed notch filters (S30). That is, it is checked whether or not there is a fixed notch filter remaining in the fixed notch filter used for suppressing the first resonance.

If there is a fixed notch filter that is not currently operating, the notch frequency of the fixed notch filter not currently operating is set to the resonance frequency of the second resonance (S35). Therefore, the second resonance can be suppressed. Here, since the frequency of the resonance is estimated in real time by the frequency estimator, the notch frequency of the fixed notch filter can be set to the frequency of the second estimated resonance in real time.

However, if there is no fixed notch filter that is not currently operating, the magnitude of the first resonance is compared with the magnitude of the second resonance. First, the smallest resonance amplitude A among the first resonances is determined (S40). That is, the size of the fixed notch filter that suppresses the smallest resonance and the size of the corresponding resonance.

Then, the smallest resonance size A is compared with the currently sensed second resonance size B (S50)

When the size B of the second resonance is larger than the size A of the smallest resonance, the notch frequency of the fixed notch filter suppressing the smallest resonance A is changed to the resonance frequency of the second resonance (S60).

However, when the magnitude (B) of the second resonance is smaller than the magnitude (A) of the smallest resonance, the frequency setting for the fixed notch filter is ended unchanged. It is because it is inefficient to leave a large resonance in order to suppress a small resonance because all the fixed notch filters currently operating suppress the resonance larger than the newly found resonance.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. . However, it should be understood that such modifications are within the technical scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (18)

A resonance detector for detecting resonance occurrence and suppression of the servo system from the current command generated in the servo controller and detecting the magnitude of the generated resonance;
A frequency estimator for estimating a resonance frequency generated from the current command in real time;
A fixed notch filter unit for filtering the current command to suppress a previously known first resonance;
A resonance comparator that compares a magnitude of the second resonance with a magnitude of the first resonance when a second resonance is detected while the fixed notch filter unit is in use; And
And a filter setting unit for changing the notch frequency of the fixed notch filter unit to the frequency of the second resonance so that the second resonance is suppressed when the magnitude of the second resonance is larger than the magnitude of the first resonance, A resonance detection and suppression system for a servo system using a filter.
The method according to claim 1,
The resonance sensor comprises:
Wherein the resonance detection and the suppression of the resonance of the servo system and the magnitude of the generated resonance are detected by using a magnitude variation or a stochastic analysis value of the current command. Suppression device.
The method according to claim 1,
The resonant comparator comprises:
Wherein the magnitude of the first resonance or the second resonance is stored in a memory.
The method according to claim 1,
In the case where the predetermined first resonance is plural and the fixed notch filter section includes a plurality of fixed notch filters,
Wherein the plurality of fixed notch filters have different notch frequencies to suppress a plurality of first resonances, respectively.
5. The method of claim 4,
The resonant comparator comprises:
Wherein when the second resonance is detected while all the fixed notch filters in the fixed notch filter unit are in use, the magnitudes of the first resonance suppressed by the fixed notch filter unit are compared with each other, And comparing the magnitude of the second resonance with the magnitude of the second resonance.
6. The method of claim 5,
The filter setter includes:
The notch frequency of the fixed notch filter suppressing the smallest resonance is changed to the second resonance frequency so that the second resonance is suppressed when the size of the second resonance is larger than the smallest resonance size of the first resonance Wherein the plurality of fixed notch filters are used for detecting and suppressing resonance of the servo system.
The method according to claim 1,
Further comprising an adaptive notch filter for filtering the current command by using a frequency estimated by the frequency estimator as a notch frequency.
8. The method of claim 7,
The filter setter includes:
Wherein when the suppression of the second resonance is detected by the resonance sensor after the filtering of the adaptive notch filter section, the notch frequency of the adaptive notch filter section is regarded as the second resonance frequency. A system for resonance detection and suppression.
9. The method of claim 8,
The filter setter includes:
Wherein the notch frequency of the fixed notch filter for suppressing the smallest resonance in the fixed notch filter portion is set to the notch frequency of the adaptive notch filter and then the operation of the adaptive notch filter is stopped. Resonance detection and suppression system using servo system.
A first filtering step of filtering a current command using a fixed notch filter unit to suppress a first resonance previously known in the servo controller;
Detecting whether or not the resonance of the servo system is generated and suppressed from the current command, and detecting the magnitude of the generated resonance;
Estimating a resonance frequency generated from the current command in real time;
Comparing the detected second resonance with the magnitude of the first resonance when a second resonance is sensed; And
And changing the notch frequency of the fixed notch filter portion to the second resonance frequency so that the second resonance is suppressed when the magnitude of the second resonance is larger than the magnitude of the first resonance A Method of Detecting and Suppressing Resonance of Servo System Using Fixed Notch Filter.
11. The method of claim 10,
Wherein the step of detecting whether the resonance of the servo system is generated or suppressed from the current command and the magnitude of the generated resonance,
Wherein a change in magnitude of the current command or a probabilistic analysis value for the current command is used as a parameter for detecting and suppressing resonance of a servo system using a plurality of fixed notch filters.
11. The method of claim 10,
Further comprising the step of storing the size of the first resonance or the second resonance in a memory.
11. The method of claim 10,
The plurality of previously known first resonances are provided,
Wherein the first filtering step comprises:
Wherein a fixed notch filter unit including a plurality of fixed notch filters having different notch frequencies is used to suppress the plurality of first resonances.
14. The method of claim 13,
If a second resonance is detected while all the fixed notch filters in the fixed notch filter unit are in use, the magnitudes of the plurality of first resonances being currently suppressed are compared, and the magnitude of the smallest resonance among them and the magnitude of the second resonance And comparing the sizes of the plurality of fixed notch filters with each other.
15. The method of claim 14,
The step of changing the notch frequency of the fixed notch filter portion so that the second resonance is suppressed includes:
And changing the notch frequency of the fixed notch filter suppressing the smallest resonance to the second resonant frequency so that the second resonance is suppressed when the magnitude of the second resonance is larger than the magnitude of the smallest resonance Wherein a plurality of fixed notch filters are used to detect and suppress the resonance of the servo system.
11. The method of claim 10,
Further comprising a second filtering step of filtering the current command using an adaptive notch filter having the estimated frequency as a notch frequency when a second resonance is detected while the first resonance is suppressed A Method for Detecting and Suppressing Resonance of a Servo System Using Two Fixed Notch Filters.
17. The method of claim 16,
Further comprising the step of considering the notch frequency of the adaptive notch filter section as the second resonance frequency when suppression of the second resonance after the filtering of the adaptive notch filter is sensed. A method for detecting and suppressing resonance of a system.
18. The method of claim 17,
Characterized in that the filter setter further comprises stopping the operation of the adaptive notch filter after setting the notch frequency of the fixed notch filter in the fixed notch filter section to the notch frequency of the adaptive notch filter section A Method of Detecting and Suppressing Resonance of Servo System Using Fixed Notch Filter.

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