JPH11304637A - Control device for vibration table - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a control device by which the excitation of a vibration table can be controlled in a short time by a method wherein, on the basis of a compensation signal which is input to the vibration table, the compensation-wave signal of the higher-harmonic component, of an acceleration signal in an excitation axial direction, which is changed into a vector is generated and the vibration table is excited by the compensation-wave signal. SOLUTION: While a vibration table 1 is being excited, an acceleration signal, in an excitation axial direction, measured by an accelerometer 3 is applied by an amplifier 4, and it is passed through an A/D converter 5 so as to be sent to a control device 30. By a first computing part in the control device 30, the higher-harmonic component of the acceleration signal in the excitation axial direction on the excitation table 1 is changed into a vector. By a second computing part, a vibration-table transfer characteristic with reference to the frequency component of N-order higher-harmonics is identified on the basis of a compensation signal which is input to the vibration table 1 and on the basis of the acceleration signal on the vibration table 1, and the compensation-wave signal of the N-order higher harmonics is generated. Until the magnitude of an observed vector becomes sufficiently small, a vibration- table transfer-function vector estimation value is updated sequentially. The compensation-wave signal is input to a servoamplifier 8 via a D/A converter 7 so as to be sent to an actuator 9, and a compensation computing operation can be performed in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a shaking table control device applied to a shaking table system.

[0002]

2. Description of the Related Art Conventionally, in a shaking table system, a test sample is mounted on a table serving as a shaking table, and a target waveform is reproduced to check the strength of the test sample with respect to an input waveform. Used for purpose. The shaking table controller used in this shaking table system needs to accurately reproduce the target wave, and the actual control method is to make the response waveform follow the target waveform as much as possible.

FIG. 8 is an overall system diagram of a conventional shaking table controller. An acceleration signal measured by the accelerometer 3 during the vibration test using the shaking table 1 is amplified by the amplifier 4 and is taken into the computer 6 via the A / D converter 5. In Calculator 6,
Perform the compensation calculation of the input wave for the next excitation,
A signal to be excited next time is input to the actuator 9 via the D / A converter 7 and the servo amplifier 8, and the vibration table 1
To excite.

FIG. 9 is a flow chart of a calculation for compensating an input wave for explaining a specific calculation content in the computer 6. The contents of the operation are roughly classified into two types. one,
This is a calculation at the time of vibration when grasping the transfer characteristic from the input to the vibrator to the table response (characteristic grasping vibration).

In this case, as shown in FIG. 9, an acceleration signal which becomes an input 27 is converted from time data to frequency data by a Fourier transform 10, converted from an acceleration to a displacement signal by a second-order integration 11, and this displacement signal is further converted. By performing the inverse Fourier transform 12, a displacement signal in the time domain to be input to the vibrator is obtained. The vibration 13 represents a system including a vibrator and a table (the vibration table 1).

The response acceleration signal in the time domain observed on the table is converted into frequency data by performing a Fourier transform 14, and this frequency data and the Fourier transform 1 are used.
Frequency response calculation 15 from both of the input signals converted at 0
By performing the above, the transfer characteristics of the shaking table system can be obtained. The transfer characteristics obtained here have a 6 × 6 matrix configuration because the table is generally controlled with six degrees of freedom.

Another operation is an operation for compensating an input wave for excitation using the transfer characteristics obtained above (input compensation excitation). In this case, first, the result of performing the inverse characteristic calculation 17 of the transfer characteristic obtained above and the target wave 28
An initial input compensation calculation 19 is performed from both the target wave data in the frequency domain obtained by performing the Fourier transform 18 on. Then, the obtained initial input compensation wave is subjected to the second-order integration 20 and the inverse Fourier transform 21 to generate an input signal to the vibrator.

Further, a signal obtained from a deviation 29 between the response acceleration signal of the table and the target wave 28 is subjected to Fourier transform 24, and an input compensation 25 is repeatedly calculated to generate an input compensation wave.

[0009]

As described above, according to the conventional control method, when the excitation by the generated input wave for a predetermined time is completed, the compensation program is executed to generate the input wave to be excited next time. Since this is a so-called discrete excitation control method, there is a problem that a plurality of compensation calculations are required to completely reproduce an input signal, which takes a lot of time.

An object of the present invention is to provide a shaking table control device which performs compensation calculation in a short time and continuously outputs a compensation wave to control the vibration of the shaking table.

[0011]

Means for Solving the Problems To solve the above problems and achieve the object, a shaking table control device of the present invention is configured as follows.

(1) A shaking table control apparatus according to the present invention is a shaking table control apparatus for controlling the vibration of the shaking table based on the acceleration measured at the shaking table to be measured. First arithmetic means for vectorizing harmonic components of the acceleration signal in the direction of the excitation axis, and a compensation wave of the acceleration signal vectorized by the first arithmetic means based on the compensation signal input to the vibration table It comprises a second calculating means for generating a signal, and vibrating means for vibrating the shaking table with the compensation wave signal generated by the second calculating means.

(2) The shaking table control device according to the present invention is the device described in (1) above, and the second calculating means receives an input from the compensation signal and the acceleration signal in the direction of the excitation axis. The transmission characteristic of the vibration table with respect to the frequency component of the harmonic is identified for each compensation signal to be generated, and the compensation wave signal is generated.

(3) A shaking table control device according to the present invention is a shaking table control device for controlling the vibration of the shaking table based on the acceleration measured at the target shaking table. First arithmetic means for vectorizing the harmonic component of the acceleration signal in the axis direction, and a compensation wave signal of the acceleration signal vectorized by the first arithmetic means based on the compensation signal input to the shaking table A second computing means for generating a harmonic component of an acceleration signal in an interference axis direction other than the vibration axis direction observed by the shaking table, and a third computing means,
A fourth calculating means for generating a compensation wave signal of the acceleration signal vectorized by the third calculating means on the basis of the compensation signal inputted to the shaking table; and a compensation generated by the second calculating means. A first vibration means for vibrating the shaking table by a wave signal; and a second vibration means for vibrating the shaking table by a compensation wave signal generated by the fourth arithmetic means. ing.

(4) The shaking table control device of the present invention is the device described in (3) above, and the second calculating means receives an input from the compensation signal and the acceleration signal in the direction of the excitation axis. The transfer characteristic of the vibration table with respect to the frequency component of the harmonic is identified for each compensation signal to be generated, and the compensation wave signal is generated. From the acceleration signal in the interference axis direction,
The transmission characteristic of the vibration table with respect to the frequency component of the fundamental wave is identified for each input compensation signal, and the compensation wave signal is generated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is an overall system diagram of a single-axis shaking table control apparatus according to a first embodiment of the present invention. In FIG. 1, the same portions as those in FIG. 8 are denoted by the same reference numerals.

As shown in FIG. 1, a specimen 2 is mounted on a shaking table 1 and an accelerometer 3 is mounted. The accelerometer 3 includes an amplifier 4 and an A / D converter 5
Is connected to the control device 30 via the
Is connected to an actuator 9 via a D / A converter 7 and a servo amplifier 8. A displacement gauge 31 is attached to the actuator 9, and the displacement gauge 31 is connected to the servo amplifier 8.

The acceleration signal in the direction of the vibration axis measured by the accelerometer 3 during the vibration experiment using the shaking table 1 is amplified by the amplifier 4 and taken into the control device 30 via the A / D converter 5.

FIG. 2 is a diagram showing an outline of the operation of the control device 30. As shown in FIG. 2, the control device 30 includes a first calculation unit 301 and a second calculation unit 302. Hereinafter, specific calculation contents of the control device 30 will be described. Control device 3
At 0, the first operation unit 301 and the second operation unit 302 perform the following operations to generate a signal for compensating for harmonics.

The first calculation unit 301 converts the harmonic component of the acceleration signal in the direction of the excitation axis observed on the table of the shaking table 1 into a vector. The contents of the calculation are shown below.

A periodic signal x (t) having a period T (sec) is
As shown in the following equations (1) to (4), it can be expanded to a Fourier series.

[0022]

(Equation 1)

Here, a0 represents the DC component of the signal, and the other represents the n-th harmonic component. Coefficients an and b
n is the reference signals cos (nωt) and sin (n
ωt), and extracts the same harmonic component as cos
Extract the size of the component and the sin component. The n-th harmonic component extracted here can be displayed as a vector diagram of the N-th harmonic by a complex Fourier coefficient as shown in FIG. In this way, it is possible to vectorize the n-th harmonic by using the complex Fourier coefficients an and bn.

The second arithmetic unit 302 calculates the shaking table transmission characteristic for the Nth harmonic frequency component from the compensation signal input to the shaking table 1 and the acceleration signal in the direction of the excitation axis observed on the table. Identify and generate a compensation wave of the Nth harmonic. The contents of the calculation are shown below.

FIG. 4 is a control block diagram in the direction of the vibration axis by the compensation calculation. As shown in FIG. 4, X on the table
Assume that an Nth harmonic having a complex Fourier coefficient of 0 is observed (shown in equation (5)).

Next, when an Nth-order compensation wave having a complex Fourier coefficient of Y1 is input, the following equation (6) is established when a shaking table transfer function having a complex Fourier coefficient of H is considered.

[0027]

(Equation 2)

At the stage when the equation (6) is completed, X0, Y1
, X1 are known vectors, so that the shaking table transfer function vector H1 can be easily obtained.

Assuming that the complex Fourier coefficients of X0, H, Y1, and X1 are as follows, equation (6) becomes equation (7) below.

[0030]

(Equation 3)

This is represented by a matrix.

[0032]

(Equation 4)

Therefore, the shaking table transfer function vector can be estimated by the following equation (8).

[0034]

(Equation 5)

Next, the shaking table transfer function vector estimated by equation (8)

(Equation 6)

Accordingly, the compensation wave Y2 input for the second time can be obtained by the following equation (9).

[0037]

(Equation 7)

The second compensation wave Y2 calculated by the equation (9)
Is input, and the observation wave vector on the table obtained as a result is represented by X2, the following equation (10) is established.

[0039]

(Equation 8)

Here, since the complex Fourier coefficients of X1, Y2, and X2 are known, H can be easily estimated.

Assuming that the complex Fourier coefficients of X1, H, Y2 and X2 are as follows, equation (10) becomes equation (11) below. That is,

(Equation 9)

Then,

(Equation 10)

Is obtained.

Here, since the shaking table transfer function vector is a constant,

[Equation 11]

Is as follows. Therefore, the shake table transfer function vector is estimated from Expressions (7) and (11).

[0046]

(Equation 12)

Equation (13) The matrix composed of the complex Fourier coefficients of the compensation wave on the right side is a 4-by-2 rectangular matrix, and there is no inverse matrix.

However, when a pseudo inverse matrix is introduced as in the following equation (14), the shaking table transfer function vector

(Equation 13)

Can be estimated.

[0050]

[Equation 14]

Thus, the estimated shaking table transfer function vector

(Equation 15)

Thus, the compensation wave Y3 input for the third time can be obtained.

The process of sequentially updating the estimated value of the shaking table transfer function vector is performed until the magnitude of the vector observed on the table is sufficiently smaller than the fundamental wave each time. The compensation wave signal generated by the control device 30 is amplified by the servo amplifier 8 via the D / A converter 7 and sent to the actuator 9.

The shaking table control device of the first embodiment is
Unlike the conventional discrete excitation method, in which the excitation is temporarily stopped and the compensation wave for the next excitation must be calculated, the compensation wave is output continuously until the harmonic component converges to a predetermined value. There are advantages that can be done. The shaking table control device realizes a sine wave response to a sine wave input signal, which is a single frequency component containing no harmonic component, on the shaking table. In the process, the Nth harmonic converges to a predetermined value. Then, the calculation is such that the process shifts to the compensation of the (N + 1) -th harmonic, and a sine wave response can be realized on the shaking table several seconds after the compensation control is started.

(Second Embodiment) FIG. 5 is an overall system diagram of a six-axis shaking table controller according to a second embodiment of the present invention. 5, the same parts as those in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 5, a specimen 2 is mounted on a shaking table 1 and an accelerometer 3 is mounted. The accelerometer 3 is connected to a control device 40 via an amplifier 4 and an A / D converter 5, and the control device 40 includes an input controller 32, a D / A converter 7, and a servo amplifier 81.
Is connected to the actuator 9a via the. A displacement gauge 31 is attached to the actuator 9a, and the displacement gauge 31 is connected to a servo amplifier 81. Also, D
Two actuators 9b, 9b are connected to the / A converter 7 via a servo amplifier 82. Displacement gauges 32, 32 are attached to each actuator 9b, 9b.

The acceleration signals in the vibration axis direction (number of signals 1) and the interference axes other than the vibration axis direction (number of signals 5) measured by the accelerometer 3 during the vibration test using the shaking table 1 are amplified by the amplifier 4. The signal is amplified and taken into the control device 40 via the A / D converter 5.

FIG. 6 is a diagram showing an outline of the operation of the control device 40. As shown in FIG. 6, the control device 40 includes first and second calculation units 401 and 401 that generate a compensation wave in the direction of the excitation axis.
402 and third and fourth calculation units 403 and 404 that generate compensation waves in the direction of an interference axis other than the excitation axis. Hereinafter, the specific calculation contents of the control device 40 will be described.

The first and second calculators 401 and 402 for generating the compensation wave in the direction of the excitation axis are the first and second calculators 301 and 3 of the control device 30 in the first embodiment described above.
02 performs the same processing. For the direction of the interference axis other than the excitation axis, the third and fourth arithmetic units 403 and 404 perform the following calculations to generate a signal for compensating for the fundamental wave of the interference axis other than the excitation axis.

The third calculation unit 403 converts the fundamental wave component of the acceleration signal in the direction of the interference axis other than the excitation axis observed on the table of the shaking table 1 into a vector. The contents of the calculation are shown below.

A fundamental signal x (t) having a period T (sec)
Can be expanded to a Fourier series as shown in the following equations (15) to (18).

[0062]

(Equation 16)

Here, a0 represents the DC component of the fundamental wave signal, and the coefficients a and b are the co components with respect to the reference signal.
It represents the magnitude of the s component and the sine component. As described above, vectorization is possible using the complex Fourier coefficients a and b.

The fourth arithmetic unit 404 calculates the shaking table transmission characteristics for the frequency component of the fundamental wave from the compensation signal input to the shaking table 1 and the signal in the direction of the interference axis other than the excitation axis observed on the table. Identify and generate a compensation wave of the fundamental wave in the direction of the interference axis other than the excitation axis. The contents of the calculation are shown below.

FIG. 7 is a control block diagram in the direction of the interference axis other than the vibration axis by the compensation calculation. As shown in FIG.
When the input wave having the complex Fourier coefficient of is input and the interference component of the fundamental wave having the complex Fourier coefficient of C1 is observed on the table, the following equation (19) is established.

[0066]

[Equation 17]

From the equation (19), the shaking table transfer function vector Hc can be estimated by the following equation (20).

[0068]

(Equation 18)

Here,

[Equation 19]

Then, the following equation (21) is obtained.

[0071]

(Equation 20)

Therefore, the complex Fourier coefficient Z1 of the first compensation wave for the degree of freedom of interference is given by the following equation (22). That is,

(Equation 21)

Is obtained.

The first compensation wave Z calculated by the equation (21)
If 1 is input and the observation wave vector on the table obtained as a result is C2, the following equation (23) is established.

[0075]

(Equation 22)

Here, since the complex Fourier coefficients of C1, Z1, and C2 are known, the shaking table transfer function Hc can be easily estimated. Ie

(Equation 23)

Then,

(Equation 24)

Is obtained. Here, since the shaking table transfer function vector is a constant,

(Equation 25)

Is obtained. Therefore, equations (21) and (22)
Then, the shaking table transfer function vector is estimated.

[0080]

(Equation 26)

Equation (25) The matrix composed of the complex Fourier coefficients of the compensation wave on the right side is a 4-by-2 rectangular matrix, and there is no inverse matrix.

However, when a pseudo inverse matrix is introduced as in the following equation (26), the shaking table transfer function vector

[Equation 27]

Can be estimated.

[0084]

[Equation 28]

The shaking table transfer function vector thus estimated

(Equation 29)

Thus, the compensation wave Z2 input for the second time can be obtained. That is,

[Equation 30]

## EQU10 ##

As described above, the estimated value of the shaking table transfer function vector is sequentially updated, and the process is repeated until the magnitude of the vector of the degree of freedom of interference observed on the table becomes sufficiently small.

As described above, the compensation signal for each degree of freedom generated by the controller 40 is supplied to the servo controller via the input controller 32 having a function of generating a command signal to each vibrator and the D / A converter 7. The signals are amplified by the amplifiers 81 and 82 and sent to the actuators 9a, 9b and 9b.

The shaking table control device according to the second embodiment includes:
Unlike the conventional discrete excitation method in which excitation must be temporarily stopped and the compensation wave for the next excitation needs to be calculated, continuous excitation is continued until the harmonic components in the excitation axis converge to a predetermined value. And the fundamental wave component can be continuously compensated for in the direction of the interference axis other than the excitation axis, so that a few seconds after the start of the compensation control, an extremely ideal uniaxial sine wave excitation test can be performed. .

The present invention is not limited to the above embodiments, but can be implemented with appropriate modifications without departing from the scope of the invention.

[0092]

According to the shaking table control apparatus of the present invention, a compensation wave can be continuously output until the harmonic component converges to a predetermined value, and compensation calculation is performed in a short time to control the vibration of the shaking table. Can do it. In other words, by targeting a sine wave as an input signal, it is possible to continuously compensate for the reproduced wave on the shaking table, and therefore it is possible to match the target wave of excitation with the reproduced wave in a short time. According to the shaking table control device of the present invention, the transmission characteristics of the shaking table are identified for each input compensation wave from the compensation wave and the observation wave in the excitation direction. Can be generated.

According to the shaking table control apparatus of the present invention, compensation can be continuously performed until the harmonic component in the direction of the excitation axis converges to a predetermined value, and the fundamental wave component in the direction of the interference axis other than the excitation axis can be compensated. Can be continuously compensated, so that an extremely ideal vibration control of the vibration table can be performed.

According to the shaking table control device of the present invention, the ratio of the magnitude of the Nth harmonic to the fundamental wave can be set to a predetermined value, and when the ratio reaches the predetermined value, the (N + 1) th harmonic can be set. The compensation is transferred continuously. Further, from the compensation wave and the observation wave in the direction perpendicular to the vibration of the shaking table, the transfer characteristic of the vibration table is identified for each compensation wave to be input, and the magnitude of the fundamental wave component of the observation wave in the direction of the vibration perpendicular to the predetermined direction is determined. Can be set to a value.

[Brief description of the drawings]

FIG. 1 is an overall system diagram of a single-axis shaking table control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an outline of calculations performed by a control device according to the first embodiment of the present invention.

FIG. 3 is a vector diagram of an Nth harmonic by a complex Fourier coefficient according to the first embodiment of the present invention.

FIG. 4 is a control block diagram in a vibration axis direction by a compensation operation according to the first embodiment of the present invention.

FIG. 5 is an overall system diagram of a six-axis shaking table control device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing an outline of calculations performed by a control device according to a second embodiment of the present invention.

FIG. 7 is a control block diagram in a direction of an interference axis other than a vibration axis by a compensation operation according to the second embodiment of the present invention.

FIG. 8 is an overall system diagram of a shaking table control device according to a conventional example.

FIG. 9 is a flowchart of compensation calculation of an input wave according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shaking table 2 ... Test piece 3 ... Accelerometer 4 ... Amplifier 5 ... A / D converter 6 ... Computer 7 ... D / A converter 8 ... Servo amplifier 81 ... Servo amplifier 82 ... Servo amplifier 9 ... Actuator 9a ... Actuator 9b: Actuator 30: Control device 31: Displacement meter 32: Accelerometer 40: Control device 301: First calculation unit 302: Second calculation unit 401: First calculation unit 402: Second calculation unit 403: Third calculation unit 404 ... Fourth calculation unit

Claims (4)

[Claims] 1. A shaking table control device for controlling excitation of said shaking table based on acceleration measured at a target shaking table, wherein: a harmonic of an acceleration signal in a direction of a shaking axis observed at said shaking table. First computing means for vectorizing the component; second computing means for generating a compensation wave signal of the acceleration signal vectorized by the first computing means based on the compensation signal input to the shaking table; And a vibration means for vibrating the vibration table with the compensation wave signal generated by the second calculating means. 2. The second calculating means identifies a transfer characteristic of the vibration table with respect to a frequency component of a harmonic for each input compensation signal from the compensation signal and the acceleration signal in the direction of the excitation axis. The shaking table control device according to claim 1, wherein the compensation wave signal is generated. 3. A shaking table control device for controlling the vibration of said shaking table based on the acceleration measured at a target shaking table, wherein a harmonic of an acceleration signal in a direction of a shaking axis observed at said shaking table. First computing means for vectorizing the component; second computing means for generating a compensation wave signal of the acceleration signal vectorized by the first computing means based on the compensation signal input to the shaking table; Third computing means for vectorizing harmonic components of an acceleration signal in an interference axis direction other than the excitation axis direction observed by the shaking table, and the third calculating means based on a compensation signal input to the shaking table. A fourth calculating means for generating a compensation wave signal of the acceleration signal vectorized by the calculating means, and a first vibration for vibrating the shaking table by the compensation wave signal generated by the second calculating means. Means, and a compensation wave generated by the fourth arithmetic means Vibrating table control apparatus characterized by comprising a second vibration means for vibrating the vibrating table by No.. 4. The second calculating means identifies, from the compensation signal and the acceleration signal in the direction of the excitation axis, a transfer characteristic of the vibration table with respect to a frequency component of a harmonic for each input compensation signal. Generating the compensation wave signal, the fourth calculating means calculates a frequency component of a fundamental wave for each input compensation signal from the compensation signal and an acceleration signal in an interference axis direction other than the vibration axis direction. The shaking table control device according to claim 3, wherein a transfer characteristic of the shaking table with respect to is identified, and the compensation wave signal is generated.