KR102483136B1 - Device and method for suppressing resonance in servo system - Google Patents

Abstract

A device for suppressing resonance in a servo system comprises a resonance suppression unit which includes an amplitude estimator for outputting an amplitude estimate value, which is an estimated value of the amplitude of resonance generated from a current command received from a servo controller, and a frequency estimator for estimating the frequency of the resonance generated from the current command in real time by using the amplitude estimate value and outputting an estimated frequency, and detects and determines the resonance in the servo system based on the current command and the estimated frequency and suppresses the resonance. Accordingly, the device can quickly estimate and respond to resonance having various amplitudes in situations in which the resonance having the various amplitudes occur in the servo system.

Description

Automatic resonance suppression device and method of servo system {DEVICE AND METHOD FOR SUPPRESSING RESONANCE IN SERVO SYSTEM}

The present invention relates to an automatic resonance suppression method of a servo system using an amplitude estimator and a frequency estimator, and more particularly, to automatically detect resonance occurring in a servo system using a frequency estimator using an output of the amplitude estimator and to suppress the resonance. It's about the art of suppression.

[Description of State-Supported R&D]

This application was made with the support of the Ministry of Small and Medium Venture Business World Class 300 (WC300) project (robot motion control solution for flexible response to smart machines/collaborative robots, task identification number: 9991008048, detailed task number: S2563339).

A method of applying a notch filter to an output current command is widely used as a method for suppressing a resonance phenomenon of a servo system. A notch filter is a filter that outputs a signal obtained by removing components of a specific frequency band from an input signal. By using the notch filter, a resonance phenomenon of a servo system can be suppressed by removing a frequency component that causes resonance from a current command.

1 is a block diagram of a servo system according to the prior art. Referring to FIG. 1 , a conventional servo system includes a control unit and a load unit. The control unit includes a servo controller, a filter unit and a current controller. The load unit includes a motor, a load, and an encoder. In an exemplary embodiment, the load may be a plant. The servo controller generates a current command (control input) for controlling the motor of the load unit. The control input of the servo controller passes through a filter unit, and the filter unit includes filters such as a low-pass filter to remove noise and a notch filter to remove signals of a specific frequency band. The current controller provides a driving current corresponding to the control input passed through the filter unit to the motor. The encoder measures the state of the driven load and provides feedback information to the controller as feedback.

The servo controller refers to the received feedback in subsequent motor control. Here, the feedback information may be generated based on angular displacement, but is not limited thereto, and may be information generated based on angular position and/or angular velocity of control. Since specific configurations and operating methods of the current controller, motor, and encoder are well known in the art, descriptions thereof are omitted here.

For the resonance suppression method, it is necessary to know the frequency characteristics of the system. To this end, a method of applying a sine wave signal to the system and obtaining the frequency characteristics of the system through frequency analysis of input and output has been widely used in the related art. However, since it is difficult to obtain the frequency characteristics in real time, it is difficult to apply the resonance suppression method in real time.

In order to overcome this problem, a method for suppressing resonance of a servo system using an adaptive notch filter and a fixed notch filter has been proposed (Patent Document 1 and Patent Document 2 of Prior Art Documents). The method detects the resonant component of the system in real time, estimates the resonant frequency using a frequency estimator, sets the estimated frequency as the notch frequency of the adaptive notch filter, and determines the resonant frequency of the system that can change according to driving conditions. How to deal with it in real time.

The method determines whether resonance suppression is determined when the adaptive notch filter is applied, and when the resonance is suppressed by applying the adaptive notch filter, the notch frequency of the adaptive notch filter is set to the notch frequency of the fixed notch filter, and fix it In addition, when a plurality of fixed notch filters are required, the sizes of resonances are compared, and fixed notch filters for suppressing small resonances may be replaced with fixed notch filters for suppressing large resonances. The method can suppress resonance in real time without acquiring the frequency characteristics of the plant, providing great convenience to the user.

On the other hand, the conventional frequency estimator has a characteristic in which the estimation speed is proportional to the difference between the estimated frequency, which is the output value of the frequency estimator, and the frequency of the input signal, and the magnitude (amplitude) of the input signal (Non-Patent Document 1 of Prior Art Documents). . The frequency estimator is devised so that the speed of estimating the frequency does not fluctuate greatly according to the frequency band of the input signal, and is applied to the resonance suppression method of the servo system using the adaptive notch filter and the fixed notch filter to reduce the resonance of the industrial servo system. It has been widely used for frequency estimation (applied to D8 series and CSD7 series of RS Automation Co., Ltd.).

However, the frequency estimator has a disadvantage in that the frequency estimation speed varies according to the magnitude of the input signal. Therefore, since the estimation speed slows down when the magnitude of the input signal is small, when a resonance with a small magnitude occurs in an actual servo system, there is a disadvantage in estimating the frequency of the corresponding resonance slowly.

KR 10-1757267 B1 KR 10-1708739 B1

W. Bahn, T. Kim, S. Lee, and D. Cho, "Resonant frequency estimation for adaptive notch filters in industrial servo systems," Mechatronics, vol.41, pp. 45-57, 2017.

The present invention has been made to solve the above-described problems, and in a servo system, the output of an amplitude estimator is used for a frequency estimator to relax the proportional relationship between the amplitude of an input signal and the estimation speed of the frequency estimator, thereby reducing resonance of various amplitudes. It is to provide a resonance suppression device of a servo system capable of quickly estimating and responding to it.

Another object of the present invention is to provide a method for suppressing resonance of a servo system using the above device.

Another object of the present invention is to provide a computer program stored in a medium to execute the resonance suppression method of the servo system.

A resonance suppression apparatus for a servo system according to an embodiment for realizing the object of the present invention described above includes an amplitude estimator outputting an amplitude estimation value, which is a value obtained by estimating an amplitude of a resonance generated from a current command received from a servo controller; and a frequency estimator for estimating a frequency of resonance generated from the current command in real time using the estimated amplitude value and outputting an estimated frequency; detecting and determining the resonance of the servo system based on the current command and the estimated frequency. and a resonance suppression unit for suppressing resonance.

In an embodiment of the present invention, the amplitude estimator may use at least one of an adaptive filter state of the frequency estimator, an estimated frequency of a previous sample, the current command, and a statistic value of the current command to generate a resonance generated from the current command. amplitude can be estimated.

In an embodiment of the present invention, the frequency estimator may estimate the frequency of the current command as an input signal using at least one of the current command, the amplitude estimation value, an adaptive filter state, and an estimated frequency of a previous sample. can

In an embodiment of the present invention, the frequency estimator may output the estimated frequency by dividing the small amount of change of the estimated frequency by the estimated amplitude value and integrating the same.

In an embodiment of the present invention, the frequency estimator divides the minute change amount of the estimated frequency by a threshold value when the amplitude estimate value is less than or equal to a specific threshold value, and divides the minute change amount of the estimated frequency by the amplitude estimate value when the amplitude estimate value exceeds the threshold value. can

In an embodiment of the present invention, the resonance suppression unit may further include at least one of a filter unit and a resonance detection and determination unit.

In an embodiment of the present invention, the filter unit further includes an adaptive notch filter for filtering the current command using the estimated frequency as a notch frequency and a plurality of fixed notch filters, wherein the fixed notch filter is an adaptive notch filter to suppress resonance If is confirmed, parameters of the adaptive notch filter including the notch frequency may be used as filter parameters of the fixed notch filter and the values may be fixed.

In an embodiment of the present invention, the resonance sensing and determining unit determines whether or not resonance of the servo system occurs, the magnitude of resonance, and whether or not to suppress resonance using the current command, and determines whether an adaptive notch filter is used or not, and a fixed notch filter. Whether or not to switch the parameters of , if a plurality of fixed notch filters are all in use and a new resonance occurs, it is possible to determine whether to replace the fixed notch filter by comparing the size of the newly generated resonance with the size of the resonance before applying each fixed notch filter.

A resonance suppression method of a servo system according to an embodiment for realizing another object of the present invention described above includes an amplitude estimation step of outputting an amplitude estimation value, which is a value obtained by estimating an amplitude of a resonance generated from a current command received from a servo controller; a frequency estimating step of estimating a frequency of resonance generated from the current command using the amplitude estimation value in real time and outputting an estimated frequency; and a resonance suppression step of detecting, determining, and suppressing resonance of the servo system based on the current command and the estimated frequency.

In an embodiment of the present invention, the estimating the amplitude may include determining the amplitude of resonance generated from the current command using at least one of an adaptive filter state, an estimated frequency of a previous sample, the current command, and a statistical value of the current command. can be estimated

In an embodiment of the present invention, the frequency estimating step may include estimating the frequency of the current command as an input signal using at least one of the current command, the amplitude estimation value, an adaptive filter state, and an estimated frequency of a previous sample. can do.

In an embodiment of the present invention, the step of estimating the frequency may further include outputting an estimated frequency by dividing the minute change in the estimated frequency by the estimated amplitude and integrating the same.

In an embodiment of the present invention, in the step of estimating the frequency, when the estimated amplitude value is less than or equal to a specific threshold value, the minute change amount of the estimated frequency is divided by the threshold value, and when the estimated amplitude value exceeds the threshold value, the minute change amount of the estimated frequency is used as the amplitude estimate value. can share

In an embodiment of the present invention, the resonance suppression step may include a filtering step; and a resonance sensing and determining step; At least one of them may be further included.

In an embodiment of the present invention, the filtering step may include filtering the current command by using an adaptive notch filter and a plurality of fixed notch filters to set the estimated frequency as a notch frequency, wherein the fixed notch filter suppresses resonance with an adaptive notch filter If is confirmed, parameters of the adaptive notch filter including the notch frequency may be used as filter parameters of the fixed notch filter and the values may be fixed.

In an embodiment of the present invention, the resonance sensing and determining step may include determining whether an adaptive notch filter is used or not, a fixed notch filter by determining whether or not resonance of the servo system occurs, the size of resonance, and whether or not resonance is suppressed by using the current command. Whether or not the parameter is switched to , if a plurality of fixed notch filters are all in use and a new resonance occurs, it is possible to determine whether to replace the fixed notch filter by comparing the size of the newly generated resonance with the size of the resonance before each fixed notch filter is applied.

A computer program according to an embodiment for realizing another object of the present invention described above is combined with hardware and stored in a medium to execute a method for suppressing resonance of a servo system.

According to embodiments of the present invention. In a situation where resonance of various amplitudes occurs in a servo system, it is possible to quickly estimate and respond to resonances of various amplitudes by using an amplitude estimator and a frequency estimator.

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.
3 is a block diagram illustrating an example of a filter unit of FIG. 2 .
4 is a flowchart of an automatic resonance suppression method of a servo system according to an embodiment of the present invention.
5 is a flowchart of a step of estimating a frequency in real time in FIG. 4 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The detailed description of the present invention which follows refers to the accompanying drawings which illustrate, by way of illustration, specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable one skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different from each other but are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in one embodiment in another embodiment without departing from the spirit and scope of the invention. Additionally, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. Accordingly, the detailed description set forth below is not to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, along with all equivalents as claimed by those claims. Like reference numbers in the drawings indicate the same or similar function throughout the various aspects.

2 is a block diagram of a servo system according to an embodiment of the present invention.

The servo system 1 according to the present invention automatically detects resonance occurring in the servo system 1 based on the frequency estimator 110 using the output of the amplitude estimator 130 and suppresses the resonance. 10).

Referring to FIG. 2 , the servo system 1 according to an embodiment of the present invention may include a control unit 30 , a resonance suppression unit 10 and a load unit 50 .

The controller 30 may include a servo controller 310 and a current controller 330 . The servo controller 310 and the current controller 330 may perform the same functions as the servo controller and current controller described in FIG. 1 . That is, the servo controller 310 may generate a current command, and the current controller 330 may generate a driving current according to the current command.

The load unit 50 may include a motor 510 , a load 530 and an encoder 550 . The function of each component may be the same as that of the motor, load, and encoder described in FIG. 1 .

The resonance suppression unit 10 includes a frequency estimator 110 and an amplitude estimator 130 to sense and determine the resonance of the servo system 1 and suppress the resonance.

The amplitude estimator 130 outputs an amplitude estimation value, which is a value obtained by estimating an amplitude of a resonance generated from a current command generated from the servo controller 310, and the frequency estimator 110 outputs an amplitude estimation value from the current command using the amplitude estimation value. The frequency of the generated resonance is estimated in real time and the estimated frequency is output.

In another embodiment, the resonance suppression unit 10 may further include at least one of a filter unit 170 and a resonance detection and determination unit 150 .

The frequency estimator 110 receives the current command as an input and estimates the frequency of the current command in real time. The frequency estimator 110 may continuously estimate the frequency of the current command by using the amount of change in the estimated frequency with respect to the frequency of the current command in each operation period so that the estimated frequency output becomes the resonant frequency appearing in the current command. there is. For example, the frequency estimator 110 may estimate the frequency of the current command by integrating minute changes in the estimated frequency calculated for each operation period.

As the estimated frequency approaches the resonant frequency of the current command, the magnitude of the minute change in the calculated estimated frequency decreases, and the estimated frequency may converge to the resonant frequency of the input current command. Accordingly, an output of the frequency estimator 110 in a steady-state becomes an estimated frequency for the resonant frequency of the current command.

Prior to describing the frequency estimator 110 and the amplitude estimator 130 according to an embodiment of the present invention, the conventional frequency estimator may be designed as an adaptive filter-based frequency estimator represented by Equation 1 below.

[Equation 1]

는 추정 주파수,

는 주파수 추정 이득,

는 입력 신호로 본 발명에서는 전류 명령을 나타낸다.Here, χ is the state of the adaptive filter, ζ is the attenuation ratio of the adaptive filter,

is the estimated frequency,

is the frequency estimation gain,

is an input signal and represents a current command in the present invention.

을 계산하고 이를 적분하여 상기 입력 신호의 주파수를 추정한다. 상기 입력 신호의 크기(진폭)가 A이고, 주파수가 ω인 정현파 신호일 경우

, 상기 적응형 필터의 정상 상태(steady-state)는 하기 수학식 2로 표현될 수 있다.The conventional frequency estimator is a small amount of change in the estimated frequency per unit time.

Calculate and integrate it to estimate the frequency of the input signal. If the input signal is a sinusoidal signal with a magnitude (amplitude) of A and a frequency of ω

, the steady-state of the adaptive filter can be expressed by Equation 2 below.

[Equation 2]

Substituting Equation 2 into the equation for calculating the minute change in the estimated frequency in Equation 1 can be calculated as in Equation 3 below.

[Equation 3]

That is, the estimation speed of the conventional frequency estimator represented by Equation 1 has characteristics that are proportional to the difference between the estimated frequency and the frequency of the input signal and the magnitude of the input signal.

Conventional frequency estimators are designed not to significantly change the speed of estimating the frequency according to the frequency band of the input signal, and have been widely used for estimating the resonant frequency of industrial servo systems.

However, the frequency estimator has a disadvantage in that the frequency estimation speed varies according to the magnitude of the input signal. Therefore, since the estimation speed is slow when the magnitude of the input signal is small, when a resonance with a small magnitude occurs, the frequency of the corresponding resonance is estimated slowly.

Since resonances of various magnitudes may occur in an actual servo system, it is necessary to develop a frequency estimator whose estimation speed does not vary depending on the magnitude of an input signal.

The frequency estimator 110 according to an embodiment of the present invention determines the proportional relationship between the amplitude of the input signal and the estimated speed using the amplitude estimation value, which is the output value of the amplitude estimator 130 for estimating the amplitude of the resonance generated from the current command. can be alleviated

, 상기 진폭 추정기(130)는 하기 수학식 4 또는 수학식 5로 설계될 수 있다. If the input signal is a sinusoidal signal with a magnitude (amplitude) of A and a frequency of ω

, The amplitude estimator 130 may be designed by Equation 4 or Equation 5 below.

However, the method for estimating the amplitude of the input signal is not limited to Equations 4 and 5 below, and in the servo system 1, such as the input signal, the statistical value of the input signal, and the state of the adaptive filter. It can be calculated using obtainable figures.

[Equation 4]

는 상기 입력 신호 의 기댓값,

는 상기 입력 신호 의 분산,

은 상기 입력 신호의 진폭 추정값을 나타낸다.here,

is the expected value of the input signal,

is the variance of the input signal,

represents an amplitude estimation value of the input signal.

[Equation 5]

Equation 4 is a method of calculating the amplitude of the input signal using the input signal and its statistical value. When applied to an actual servo system, a time delay inevitably occurs because the variance from before a specific unit time to the present must be calculated, and the expected value of the sinusoidal input signal may not become zero depending on the sampling time.

That is, since the amplitude value of the current time cannot be accurately calculated according to the time delay and the sampling time, it is difficult to obtain an accurate amplitude of the input signal using the variance of the input signal as in Equation 4 above.

Equation 5 is a method of estimating the amplitude of the input signal using the state of the frequency estimator adaptive filter of Equation 1 and the estimated frequency of the previous sample. By substituting the steady state of the frequency estimator adaptive filter represented by Equation 2 into Equation 5, an amplitude estimation value in the steady state can be calculated, and the amplitude estimation value is determined according to the frequency of the input signal and the estimated frequency. Accuracy may vary.

The frequency estimator 110 according to an embodiment of the present invention divides the minute change in the estimated frequency by the amplitude estimate value when calculating the minute change in the estimated frequency, so that the estimation speed of the conventional frequency estimator depends on the amplitude of the input signal. proportionality can be alleviated.

The frequency estimator 110 according to an embodiment of the present invention may be designed as a frequency estimator based on an adaptive filter and an amplitude estimation value represented by Equation 6 below by using the conventional frequency estimator represented by Equation 1 above. there is.

[Equation 6]

은 상기 수학식 6의 추정 주파수의 미소 변화량을 0으로 나누는 것을 방지하기 위해 설정된 문턱값이다. 상기 진폭 추정값

이

보다 작은 경우 상기 추정 주파수의 미소 변화량을

으로 나누고, 상기 진폭 추정값

이

보다 큰 경우 상기 추정 주파수의 미소 변화량을

으로 나누도록 설계될 수 있다. here,

Is a threshold value set to prevent division of the minute change in the estimated frequency of Equation 6 by zero. the amplitude estimate

this

If smaller than the small change in the estimated frequency

Divided by , and the amplitude estimate

this

If greater than the small change in the estimated frequency

It can be designed to divide by

,상기 수학식 2 및 수학식 5를 상기 수학식 6 중 추정 주파수의 미소 변화량 계산식에 대입하면 하기 수학식 7과 같이 계산된다.If the input signal is a sinusoidal signal with a magnitude (amplitude) of A and a frequency of ω

, When Equations 2 and 5 are substituted into the formula for calculating the minute change in the estimated frequency in Equation 6, it is calculated as in Equation 7 below.

[Equation 7]

When the frequency estimator is designed as in Equation 6, the estimation speed of the frequency estimator of the conventional frequency estimator represented by Equation 1 is obtained by dividing the effect on the magnitude of the input signal in Equation 3 above. The characteristic proportional to the size of can be relaxed.

3 is a block diagram illustrating an example of a filter unit of FIG. 2 .

Referring to FIG. 3 , the filter unit 170 may include an adaptive notch filter 171 and a plurality of fixed notch filters 174 and 176 connected in series. Although one adaptive notch filter and two fixed notch filters are shown in FIG. 3, the order and number are merely exemplary, and various filters such as a low-pass filter for noise reduction may be further included.

Here, the adaptive notch filter 171 may filter the current command using the estimated frequency estimated by the frequency estimator 110 as a notch frequency and provide the filtered current command to the current controller 330 .

The adaptive notch filter 171 may be designed as a second-order notch filter expressed by Equation 8 below, but the present invention is not limited thereto.

[Equation 8]

는 노치 주파수, ζ는 필터의 감쇄비(damping factor)를 나타낸다.Here, s is the Laplace operator,

is the notch frequency, and ζ is the damping factor of the filter.

The notch frequency of the adaptive notch filter 171 is the estimated frequency of the frequency estimator 110 and may change over time.

When the resonance detection and determination unit 150 determines that the resonance of the fixed notch filters 174 and 176 of the filter unit 170 is suppressed using the adaptive notch filter 171, the adaptive notch filter including the notch frequency ( 171) is used as a parameter of the fixed notch filters 174 and 176 and the value is fixed.

The fixed notch filters 174 and 176 may be designed as second-order notch filters represented by Equation 9 below similarly to Equation 8, but the present invention is not limited thereto.

[Equation 9]

는 고정 노치 필터(174, 176)의 노치 주파수,

는 고정 노치 필터의 감쇄비(damping factor)를 나타낸다. 고정 노치 필터(174, 176)의 노치 주파수 및 감쇄비는 공진 감지 및 판단부(150)로부터 공진이 억제되었다고 판단되었을 때 적응 노치 필터로부터 전달받은 값이며, 시간에 따라 변화하지 않는다.here,

Is the notch frequency of the fixed notch filters 174 and 176,

represents the damping factor of the fixed notch filter. The notch frequency and attenuation ratio of the fixed notch filters 174 and 176 are values transmitted from the adaptive notch filter when the resonance detection and determination unit 150 determines that the resonance is suppressed, and does not change over time.

Resonance detection and determination unit 150 according to an embodiment of the present invention receives the current command generated by the servo controller 310 as an input signal, determines whether or not resonance of the servo system is generated and suppresses resonance, and resonance size can be detected. That is, the resonance detection and determination unit 150 may determine whether the resonance of the load unit 50 is generated or suppressed from the current command generated according to the signal fed back from the encoder.

The resonance detection and determination unit 150 uses a value capable of determining the occurrence of resonance, such as the current command obtainable from the servo system 1 and a statistical value using the current command, and if the value exceeds a specific threshold, the estimation is performed. frequency can be designed to determine whether or not to apply the adaptive notch filter 171.

In addition, it is determined that the resonance is suppressed using the adaptive notch filter 171, and when it is determined that the resonance is suppressed, the parameter of the adaptive notch filter 171 is set as the parameter of the fixed notch filters 174 and 176, and the value can be designed to fix

After setting the fixed notch filters 174 and 176, the resonance detection and determination unit 150 determines whether a new resonance occurs, sets the notch frequency of the adaptive notch filter to the estimated frequency of the new resonance, and suppresses the new resonance. It may be designed to operate by repeating the process of determining and setting parameters of a fixed notch filter other than the fixed notch filter set before the new resonance occurs.

The resonance detection and determination unit 150 stores the magnitude of the resonance using a value capable of determining the occurrence of the resonance, and when all of the plurality of fixed notch filters 174 and 176 are in use and a new resonance occurs, a new resonance is generated. It may be designed to determine whether to replace the fixed notch filter by comparing the size of the generated resonance with the size of the resonance before parameter setting of each fixed notch filter.

When all of the plurality of fixed notch filters 174 and 176 are in use and the magnitude of the newly generated resonance is smaller than the resonance of each fixed notch filter prior to parameter setting, the resonance detection and determination unit 150 does not perform a separate operation. can be designed

If the size of the newly generated resonance is larger than the resonance before setting the parameters of a certain fixed notch filter, the adaptive notch filter 171 is operated to determine whether to suppress the resonance, and if it is determined that the resonance is suppressed, the size of the resonance is small. It can be designed to replace and fix the parameters of the fixed notch filter with the parameters of the adaptive notch filter 171.

At this time, if it is not determined that the resonance is suppressed, it may be designed to continue using the existing fixed notch filter. The resonance detection and determination unit 150 may be designed to replace and maintain the plurality of fixed notch filters 174 and 176 by repeating the above process when all of the plurality of fixed notch filters 174 and 176 are in use.

4 is a flowchart of a resonance suppression method of a servo system according to an embodiment of the present invention. 5 is a flowchart of a step of estimating a frequency in real time in FIG. 4 .

The resonance suppression method of the servo system according to the present embodiment may be performed in substantially the same configuration as the resonance suppression unit 10 of the servo system 1 of FIG. 2 . Therefore, components identical to those of the resonance suppression unit 10 of FIG. 2 are given the same reference numerals, and repeated descriptions are omitted.

Also, the resonance suppression method of the servo system according to the present embodiment may be executed by software (application) for performing resonance suppression of the servo system.

Referring to FIG. 4 , a method for suppressing resonance of a servo system includes calculating an amplitude estimation value of a resonance generated from a current command generated from a servo controller (step S10), and a frequency of resonance generated from the current command based on the amplitude estimation value. It may include estimating in real time (step S30), detecting and determining the resonance of the servo system using the current command and the estimated frequency, and suppressing it (step S50).

In one embodiment, the amplitude estimating step (step S10) may estimate the amplitude of resonance generated from the current command using an adaptive filter state, an estimated frequency of a previous sample, a current command, and a statistical value of the current command. there is.

In an embodiment, the frequency estimating step (step S30) may estimate the frequency of the input signal using the current command, the amplitude estimation value, the adaptive filter state, and the estimated frequency of the previous sample. Here, the estimated frequency may be output by dividing the small amount of change of the estimated frequency by the estimated amplitude value and integrating the same.

Referring to FIG. 5 , in order to prevent division by 0 when dividing by the estimated amplitude, it is first determined whether the estimated amplitude is equal to or less than a predetermined threshold (step S31).

When the estimated amplitude value is less than or equal to a specific threshold value, it can be calculated by dividing the minute change amount of the estimated frequency by the threshold value (step S33), and when exceeding the threshold value, by dividing the minute change amount of the estimated frequency by the amplitude estimate value (step S35). .

In one embodiment, the step of detecting and determining the resonance of the servo system and suppressing it (step S50) may further include a filtering step and a resonance sensing and determining step.

Here, the filtering step further includes an adaptive notch filter for filtering the current command using the estimated frequency as a notch frequency, and a plurality of fixed notch filters, wherein the fixed notch filter generates a notch when resonance suppression is confirmed by the adaptive notch filter. It is characterized in that parameters of the adaptive notch filter including frequency are used as filter parameters of the fixed notch filter and the values are fixed.

In addition, the sensing and determining of the resonance may include determining whether or not a resonance occurs in the servo system, a size of the resonance, and whether or not the resonance is suppressed using the current command to determine whether an adaptive notch filter is used or whether a parameter is converted to a fixed notch filter. , When a plurality of fixed notch filters are all in use and a new resonance occurs, it can be determined whether to replace the fixed notch filter by comparing the size of the newly generated resonance with the size of the resonance before applying each fixed notch filter.

Such a method for suppressing resonance of a servo system may be implemented as an application or implemented in the form of program instructions that can be executed through various computer components and recorded on a computer-readable recording medium. The computer readable recording medium may include program instructions, data files, data structures, etc. alone or in combination.

Program instructions recorded on the computer-readable recording medium may be those specially designed and configured for the present invention, or those known and usable to those skilled in the art of computer software.

Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-optical media such as floptical disks. media), and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like.

Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes such as those produced by a compiler. The hardware device may be configured to act as one or more software modules to perform processing according to the present invention and vice versa.

Although the above has been described with reference to embodiments, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. You will understand.

1: servo system
10: resonance suppression unit
110: frequency estimator
130: amplitude estimator
150: resonance detection and determination unit
170: filter unit
30: control unit
310: servo controller
330: current controller
50: load part
510: motor
530: load
550: encoder
171 Adaptive notch filter
174, 176: fixed notch filter

Claims (17)

an amplitude estimator outputting an amplitude estimation value, which is a value obtained by estimating an amplitude of a resonance generated from a current command received from the servo controller; and
A frequency estimator for estimating a frequency of resonance generated from the current command in real time using the estimated amplitude value and outputting an estimated frequency; detecting and determining resonance of the servo system based on the current command and the estimated frequency; and Including; a resonance suppression unit for suppressing resonance,
The frequency estimator estimates a frequency of the current command, which is an input signal, using at least one of the current command, the amplitude estimation value, an adaptive filter state, and an estimated frequency of a previous sample. .
According to claim 1,
The amplitude estimator estimates an amplitude of resonance generated from the current command using at least one of an adaptive filter state of the frequency estimator, an estimated frequency of a previous sample, the current command, and a statistical value of the current command. Resonance suppression device in the system.
an amplitude estimator outputting an amplitude estimation value, which is a value obtained by estimating an amplitude of a resonance generated from a current command received from the servo controller; and
A frequency estimator for estimating a frequency of resonance generated from the current command in real time using the estimated amplitude value and outputting an estimated frequency; detecting and determining resonance of the servo system based on the current command and the estimated frequency; and Including; a resonance suppression unit for suppressing resonance,
The amplitude estimator estimates an amplitude of resonance generated from the current command using at least one of an adaptive filter state of the frequency estimator, an estimated frequency of a previous sample, the current command, and a statistical value of the current command. Resonance suppression device in the system.
According to claim 1,
wherein the frequency estimator divides the minute change in the estimated frequency by the estimated amplitude value and integrates it to output the estimated frequency.
According to claim 4,
The frequency estimator divides the minute change amount of the estimated frequency by a threshold value when the amplitude estimate value is less than or equal to a specific threshold value, and divides the minute change amount of the estimated frequency value by the amplitude estimate value when the amplitude estimate value exceeds the threshold value. .
According to claim 1,
The resonance suppression unit further comprises at least one of a filter unit and a resonance detection and determination unit, the resonance suppression device of the servo system.
According to claim 6,
The filter unit further includes an adaptive notch filter and a plurality of fixed notch filters for filtering the current command by using the estimated frequency as a notch frequency,
The fixed notch filter uses parameters of the adaptive notch filter including the notch frequency as filter parameters of the fixed notch filter when resonance suppression is confirmed with the adaptive notch filter and fixes the value. Resonance suppression device of the servo system.
According to claim 6,
The resonance detection and determination unit determines whether or not resonance of the servo system occurs, the size of resonance, and whether or not to suppress resonance using the current command, and determines whether an adaptive notch filter is used, whether a parameter is converted to a fixed notch filter, and a plurality of When all fixed notch filters are in use and a new resonance occurs, a resonance suppression device of a servo system that determines whether to replace the fixed notch filter by comparing the size of the new resonance with the size of the resonance before applying each fixed notch filter.
an amplitude estimation step of outputting an amplitude estimation value, which is a value obtained by estimating an amplitude of a resonance generated from a current command received from the servo controller;
a frequency estimating step of estimating a frequency of resonance generated from the current command using the amplitude estimation value in real time and outputting an estimated frequency; and
A resonance suppression step of sensing, determining, and suppressing resonance of the servo system based on the current command and the estimated frequency;
The frequency estimating step may include estimating a frequency of the current command, which is an input signal, using at least one of the current command, the amplitude estimation value, an adaptive filter state, and an estimated frequency of a previous sample. method.
According to claim 9,
The estimating amplitude may include estimating an amplitude of a resonance generated from the current command using at least one of an adaptive filter state, an estimated frequency of a previous sample, the current command, and a statistical value of the current command. suppression method.
an amplitude estimation step of outputting an amplitude estimation value, which is a value obtained by estimating an amplitude of a resonance generated from a current command received from the servo controller;
a frequency estimating step of estimating a frequency of resonance generated from the current command using the amplitude estimation value in real time and outputting an estimated frequency; and
A resonance suppression step of sensing, determining, and suppressing resonance of the servo system based on the current command and the estimated frequency;
The estimating amplitude may include estimating an amplitude of a resonance generated from the current command using at least one of an adaptive filter state, an estimated frequency of a previous sample, the current command, and a statistical value of the current command. suppression method.
According to claim 9,
In the frequency estimating step, the step of outputting the estimated frequency by dividing the minute change of the estimated frequency by the amplitude estimate value and integrating it;
According to claim 12,
The frequency estimating step may include dividing a minute change in the estimated frequency by a threshold value when the estimated amplitude value is less than or equal to a specific threshold value, and dividing the minute change amount in the estimated frequency by the estimated amplitude value when the estimated amplitude value exceeds the threshold value, suppressing resonance of the servo system. method.
According to claim 9,
The resonance suppression step may include a filtering step; and a resonance sensing and determining step; Resonance suppression method of a servo system further comprising at least one of the following.
According to claim 14,
In the filtering step, the current command is filtered by using the estimated frequency as a notch frequency using an adaptive notch filter and a plurality of fixed notch filters;
The fixed notch filter uses parameters of the adaptive notch filter including the notch frequency as filter parameters of the fixed notch filter when resonance suppression is confirmed with the adaptive notch filter and fixes the value. Resonance suppression method of the servo system.
According to claim 14,
The resonance sensing and determining step may include determining whether or not resonance of the servo system has occurred, the magnitude of resonance, and whether or not to suppress resonance using the current command, and determining whether an adaptive notch filter is used, whether a parameter is converted to a fixed notch filter, and a plurality of A method of suppressing resonance in a servo system that determines whether to replace the fixed notch filter by comparing the size of the newly generated resonance with the size of the resonance before applying each fixed notch filter when all two fixed notch filters are in use and a new resonance occurs.
A computer program stored in a medium combined with hardware to execute the resonance suppression method of a servo system according to any one of claims 9 to 16.

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