JP2002156308A - Shaking table and its control device and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate on real time basis the fluctuations of a shaking table transfer characteristics caused by a force (test piece reaction) applied to the shaking table by the test piece which is an excitation object, or the like. SOLUTION: This shaking table, equipped with this control device for feeding back a detection signal of a motion state measuring means 105, comparing the detection signal with a command signal which is a target inputted from the outside, and controlling a shaker 104 based on a deviation, has a reference signal generating means 3 having the shaking table transfer characteristics of the command signal which is the target, for generating a reference signal which is the target of a shaking table output signal by taking the command signal, an identification means 6 for identifying the fluctuations of the shaking table transfer characteristics due to disturbance from the reference signal from the reference signal generation means 3 and the detection signal detected by the measuring means 105, and calculating a control coefficient in order to compensate the identified fluctuations, and a control operation means 2 for correcting the command signal following the control coefficient from the identification means 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaking table, a control device therefor, and a control method, and more particularly, to a shaking table transmission by a force (specimen reaction force) exerted on a shaking table by a specimen to be excited. The present invention relates to a shaking table for compensating for fluctuations in characteristics in real time, a control device and a control method thereof.

[0002]

2. Description of the Related Art According to a conventional method of controlling a shaking table, for example, a "servo mechanism of a three-dimensional 6-degree-of-freedom shaking table" (Machine Design, Vol. 35, No. 4, April 1991, pp. 25-28)
Page), the displacement / acceleration of the shaking table is fed back (hereinafter referred to as prior art 1).

[0003] Also, Japanese Patent Application Laid-Open No. 10-318879,
As disclosed in Japanese Patent Application Laid-Open No. H11-94689, there is a method of estimating a disturbance using a disturbance observer, and generating and controlling a compensation signal for canceling the disturbance (hereinafter referred to as Conventional Technique 2).

Further, as disclosed in WO97 / 11344, there is a method of measuring a specimen reaction force and generating and controlling a compensation signal for canceling the reaction force (hereinafter referred to as prior art 3). .

Further, as a general control method, there is an adaptive control method in which a control target is identified and an input signal to the control target is corrected using a compensator having an inverse characteristic of the control target (hereinafter referred to as prior art 4). ).

Further, as disclosed in Japanese Patent Application Laid-Open No. 6-195105, a dynamic characteristic model of a system in which a control target and an adjusting operation unit are combined is identified and adjusted in order to realize the same transfer characteristic as a reference model. There is also a method of determining a control parameter of the operation unit (hereinafter, referred to as conventional technology 5).

Further, "Study on Electro-hydraulic Vibration Testing Machine (3rd Report)" (Transactions of the Japan Society of Mechanical Engineers, Vol. 42, No. 3)
No. 61, September 1976, pp. 2744-2751), there is also a method of compensating for the reaction force of a specimen using a shaker control circuit having a model of the specimen (hereinafter referred to as prior art 6). ).

[0008]

However, in the method of the prior art 1, the compensation effect decreases as the weight of the specimen becomes larger than the weight of the table. No consideration was given to reducing the compensation effect when shaking.

Further, the method of the prior art 2 requires an accurately identified shaking table model when estimating a disturbance, which is not always easy.

Further, in the method of the prior art 3, a means for measuring the reaction force of the specimen, which is not provided in a general shaking table, is required.

Further, in the method of the prior art 4, the dynamic characteristics of the shaking table are generally represented by a delay system of the fourth or higher order, and the poles and the zero point increase when the specimen resonates. That is, since the shaking table has higher-order transmission characteristics, it takes a relatively long time to identify the shaking table. However, tests using a shaking table often end in about several tens of seconds, and identification in a shorter time is required.

Further, in the method of the prior art 5, the control parameters of the adjusting operation section must be kept for a certain period of time in consideration of the delay of the controlled object, and when the characteristics of the controlled object change during this time. Was not taken into account that he could not compensate.

Further, in the method of the prior art 6, when the characteristics of the test sample change during the excitation, or when the test sample has nonlinear characteristics, the compensation is not always performed.

The details are as follows.

FIG. 4 shows an example of a configuration of a conventional vibration table. A table 101 is supported on a base 103 via a bearing 102. However, the bearing 102 is not always necessary depending on the configuration of the shaking table. Also, the table 101 is a vibrator 1 that is also installed on the foundation 103.
04 via a piston 104a. Further, the table 101 is provided with an acceleration measuring means 105. The vibration exciter 104 is controlled using at least a value measured by the acceleration measuring means 105 as a feedback signal so as to reproduce a target waveform input by the control device 106. Specimen 1 to be tested is placed on table 101
07 is installed.

FIG. 5 schematically shows a control block diagram of the shaking table.

An acceleration command signal U from a signal generator such as an earthquake acceleration is input to the control device 106 of the vibration exciter 104 in the form of, for example, a voltage signal proportional to the target output acceleration. The realized acceleration Y of the table 101 measured by the acceleration measuring means 105 is fed back and subjected to the processing indicated by the block B. Then, the acceleration command signal U is compared with a signal obtained by performing an appropriate processing P, and the deviation signal E is obtained. Is calculated.
Appropriate processing indicated by block Q is applied to the deviation signal E, and an excitation signal C of the exciter 104 is output. Exciter 104
Then, a table excitation force F is generated based on the excitation signal C. Here, a transfer function from the excitation signal C to the table excitation force F is represented by A. As a result, the realized acceleration Y is realized.

Assuming that the mass of the movable portion such as the piston 101 of the table 101 or the exciter 104 is M, the transfer function of the acceleration Y realized from the table excitation force F is 1 / M. At this time, when the test piece 107 is mounted on the table 101, the test piece 107 vibrates due to the realized acceleration Y, and a load F ′ is applied to the table 101 from the test piece 107. Here, a transfer function from the actual acceleration Y to the load F ′ is represented by T.

The signal fed back via the block B may be the speed or displacement of the table 101 or the piston 104a of the vibrator 104.

The transfer function from the acceleration command signal U to the actual acceleration Y when the test piece 107 is not mounted (no load state) is represented by (Equation 1).

[0021]

(Equation 1)

Blocks B, P, and Q have G in the operating frequency range.
Is adjusted to be 1 before use. However, when the specimen 107 is mounted, the transfer function is (Equation 2)
It changes like

[0023]

(Equation 2)

Therefore, the transfer characteristic of the shaking table changes due to the addition of the transfer function T, and the waveform reproducibility decreases when the blocks B, P, and Q adjusted by (Equation 1) are used. When the transfer function T is known in advance, the waveform reproducibility can be maintained by adjusting GH to be approximately 1 in the used frequency range. However, the transfer function T is non-linear, If it changes, it has been difficult to adjust.

Even if the transfer function T can be measured, it takes time and labor to perform such a measurement for each specimen and to adjust the blocks B, P, and Q.

In view of the above, it is an object of the present invention to perform compensation in real time and to cope with changes in the characteristics of a specimen, without requiring a specimen model and an accurate shaking table model. An object of the present invention is to provide a shaking table capable of real-time compensating for fluctuations in shaking table transfer characteristics due to disturbances such as a reaction force of a specimen, which can be realized only with the provided sensor, a control device therefor, and a control method.

[0027]

Means for Solving the Problems In order to solve the above-mentioned problems, the configuration of the invention of the control device for the shaking table according to the present invention is as follows.
A table for mounting the specimen, a vibrator for vibrating the table, and measuring means for measuring the motion state of the table are provided, and a detection signal of the measuring means is fed back, and the fed back detection signal is Compare with a target command signal input from the outside, in the control device of the shaking table to control the vibrator based on the deviation,
Reference signal generation having a shaking table transmission characteristic of the target command signal or a previously identified shaking table transmission characteristic in a no-load state, and capturing the command signal to generate a target reference signal of the shaking table output signal Means, and a reference signal from the reference signal generation means and a detection signal detected by the acceleration measurement means to identify a change in shaking table transfer characteristics due to disturbance,
An identification means for calculating a control coefficient for compensating the identified fluctuation, and a control operation means for correcting the command signal according to the control coefficient from the identification means.

Preferably, the input / output signal of the reference signal generation means, the input signal of the identification means, and the input / output signal of the control operation means are unified as either an acceleration signal or a displacement signal. Things.

Preferably, a low-pass filter or a band-pass filter is provided for each of the two input signals to the identification means.

Still preferably, the characteristics of a low-pass filter or a band-pass filter provided for each of the two input signals to the identification means are identical.

Further, the invention of a vibration table according to the present invention comprises a table for mounting a specimen, a vibrator for vibrating the table, and a measuring means for measuring a motion state of the table. A vibration control device that feeds back a detection signal of the measurement unit, compares the feedback detection signal with a target command signal input from the outside, and controls the vibrator based on the deviation. The table has a shaking table transmission characteristic of the target command signal or a previously identified shaking table transmission characteristic in a no-load state, and captures the command signal to generate a target reference signal of the shaking table output signal. A reference signal generating means, and a reference signal from the reference signal generating means and a detection signal detected by the measuring means identify fluctuations in shaking table transfer characteristics due to disturbances. And identifying means for calculating a control factor to compensate for, and has a control arithmetic unit for correcting the command signal according to the control coefficients from the identification means.

According to the invention, there is provided a method of controlling a shaking table according to the present invention, in which a detection signal of a measuring means for measuring a movement state of a table is fed back, and the fed back detection signal and a target command signal inputted from outside. In the control method of the shaking table, in which the control device controls the shaker based on the deviation, the shaking table transmission characteristic of the target command signal or the shaking table transmission in a no-load state identified in advance. The reference signal generating means generates a reference signal as a target of the shaking table output signal by taking in the command signal, and obtains a shaking table transmission characteristic due to a disturbance from the reference signal and the detection signal detected by the measuring means. Variability of
In order to compensate for the identified fluctuation, a control coefficient is calculated by the identification means, and the command signal is corrected by the control operation means in accordance with the control coefficient to identify the fluctuation of the shaking table transfer characteristic due to disturbance and to compensate for this fluctuation. Is repeated, and the command signal to the control device of the shaking table is compensated using the latest control coefficient.

Further, another configuration of the invention for controlling the shaking table according to the present invention is such that the detection signal of the measuring means for measuring the motion state of the table is fed back, and the fed back detection signal and the target inputted from the outside are fed back. In the control method of the shaking table in which the control device controls the vibrator based on the deviation, the shaking table transfer characteristic of the target command signal or the no-load state previously identified The shaking table transmission characteristics of the above, the reference signal targeted by the shaking table output signal by taking in the command signal is generated by the reference signal generating means, and the reference signal and the detection signal detected by the measuring means generate a disturbance signal. A fluctuation of the shaking table transfer characteristic is identified, a control coefficient is calculated by the identification means to compensate for the identified fluctuation, and the command signal is controlled and calculated according to the control coefficient. Corrected by stage, the one in which a signal for compensating the signal used to identify variations in the shaking table transfer characteristics are unified to one of the acceleration signal or displacement signal.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a control block diagram showing an embodiment of the shaking table according to the present invention.

In the figure, the same parts as those of the conventional shaking table control block diagram shown in FIG.

Reference numeral 1 denotes a signal generator for generating an acceleration command signal u. Reference numeral 2 denotes a control operation means for correcting the acceleration command signal u and outputting a corrected acceleration command signal u '. Reference numeral 3 denotes a reference signal generating means for calculating a target output acceleration y 'based on the corrected acceleration command signal u'. Reference numeral 4 denotes a reference signal filter for removing noise and DC components contained in the output acceleration y '.

Reference numeral 5 denotes an output signal filter for removing noise and DC components included in the actual acceleration y obtained by the acceleration measuring means 105 (see FIG. 4). Numeral 6 denotes an identification means for identifying the fluctuation of the shaking table transfer characteristic caused by the specimen 107 based on the reference signal output from the reference signal filter 4 and the output signal output from the output signal filter 5, and controlling the control operation means 2. This is for calculating the coefficient.

A portion constituted by the control operation means 2 to the identification means 6 is indicated by a broken line, and the function will be described in detail below. The control calculation means 2 compensates for the fluctuation of the shaking table transfer characteristics due to the test piece 107, and its function is realized, for example, as follows.

The acceleration command signal u [k] from the signal generator 1
(K is the number of samplings)
The control coefficients ai, bj (i =
1,..., N, j = 0,..., M), and generates a corrected acceleration command signal u ′ [k] based on (Equation 3).

[0040]

(Equation 3)

However, the initial values of the control coefficients are b0 = 1, a
i, bi = 0 (i = 1,..., n). The generated corrected acceleration command signal u ′ [k] is input to the shaking table controller 106 and the reference signal generator 3.

The reference signal generating means 3 should generate a shaking table having a target shaking table transmission characteristic or a previously identified shaking table transmission characteristic in a no-load state based on the corrected acceleration command signal u '[k]. The target output acceleration y '[k] is calculated, and its function is realized as follows, for example.

The system matrix, control matrix, output matrix of the target shaking table or the shaking table in a no-load state identified in advance,
When the transfer matrices are set as Ast, Bst, Cst, and Dst, and the state variable vector is set as Xst [k], the target output acceleration y ′ [k] is obtained by (Equation 4).

[0044]

(Equation 4)

The target output acceleration y '[k] calculated in this way and the actual acceleration y [k] obtained by the acceleration measuring means 105 are input to the reference signal filter 4 or the output signal filter 5, respectively. You.

The output signal filter 5 is provided for the acceleration measuring means 1.
05 to generate an output signal o [k] from which noise and a DC component included in the realized acceleration y [k] are removed.
The reference signal filter 4 generates a reference signal r [k] that matches the output signal in a no-load state.

For example, the filters 4 and 5 are band-pass filters, and their functions are realized as follows.

The system matrix, control matrix, output matrix, and transfer matrix of the band-pass filter are Abp, Bbp,
Cbp and Dbp, and the state variable vector is Xbp
[K], the reference signal r [k] is obtained by (Equation 5).

[0049]

(Equation 5)

The output signal o [k] is obtained by (Equation 6).

[0051]

(Equation 6)

The reference signal r [k] and the output signal o
[K] is input to the identification means 6.

The identification means 6 identifies a change in the shaking table transfer characteristics due to a disturbance such as a reaction force of the specimen 107, and generates a control coefficient for realizing the inverse characteristic of the identified change. For example, the function of the identification means 6 is realized as follows. Using the successive least squares method, the fluctuation of the shaking table transfer characteristic due to disturbance is identified as shown in (Equation 7).

[0054]

(Equation 7)

The obtained a'j, b'i (where i =
1,..., N, j = 0,.
Is obtained by (Equation 8).

[0056]

(Equation 8)

This control coefficient is sent to the control calculation means 2,
The dynamic characteristic of the control calculation means 2 is changed.

FIG. 2 is a flowchart collectively showing a method of controlling the shaking table by the control device. First, the parameters of the control calculation means 2 are set as b0 = 1, ai, bi = 0.
(I = 1,..., N) is initialized (110), and the transfer function of the control calculation means 2 is set to 1, that is, the state where no compensation is performed. Thereafter, the acceleration command signal u output from the signal generator 1 is read (120), and the acceleration command signal u is input to the control calculation means 2 to calculate the corrected acceleration command signal u 'according to (Equation 3) (130). ), And outputs it to the control device 106 (140).

The corrected acceleration command signal u 'is passed through the reference signal generating means 3 to calculate the target output acceleration y' [k] according to (Equation 4), and passed through the reference signal filter 4 (Equation 4). The reference signal r is calculated according to 5) (1)
50). Further, the realized acceleration y is read (160),
The output signal o is calculated according to (Equation 6) through the output signal filter 5 (170).

Using the reference signal r and the output signal o calculated as described above as identification inputs, the fluctuation of the shaking table transfer characteristics due to disturbance is identified as shown in (Equation 7) by the sequential least squares method (180). . From the result of this identification, the control coefficient of the control calculation means 2 is calculated according to (Equation 8) (19)
0). The operation after the above initialization is repeatedly performed using the control coefficient thus obtained.

The order of processing is not limited to this, and if equivalent processing can be performed, the order may be changed or parallel processing may be performed. For example, in the range where the reference signal and the output signal are substantially synchronized, the order of the operations after the above initialization may be changed. FIG. 3 schematically shows the principle of compensating the shaking table transfer characteristics of the present embodiment in terms of the relationship between frequency and gain.

Due to the influence of disturbance such as the reaction force of the test piece 107, the transfer table from the acceleration command signal u to the realized acceleration y [k] has the characteristic shown in FIG. ), The acceleration command signal u is corrected by the control operation means 2 of the transfer characteristic, and as a result, the shaking table transfer characteristic shown in FIG. Further, even if the characteristics of the test piece 107 change, identification of the fluctuation of the shaking table transfer characteristics by the test piece 107 is repeatedly performed.
The shaking table transfer characteristics shown in (c) are realized.

Here, the reference signal filter 4 and the output signal filter 5 are not limited to band-pass filters, and both the filters 4 and 5 may be low-pass filters for removing noise. Also, preferably, both filters 4,
Although the characteristics of the filters 5 and 5 are the same, if the difference between the reference signal and the output signal becomes sufficiently small in the no-load state, the characteristics of the two filters 4 and 5 may not be the same.
Further, when the DC component and noise of both signals are sufficiently small, both filters 4 and 5 are not required.

The signals handled by the control operation means 2, the reference signal generation means 3, the reference signal filter 4, the output signal filter 5, and the identification means 6 are not limited to acceleration signals, but may be displacement signals.

The identification means 6 calculates the transfer characteristic of the output signal with respect to the reference signal, calculates a transfer function by curve-fitting the curve, and sends a control coefficient consisting of a parameter of the inverse transfer function to the control calculation means 2. The calculating means may correct the acceleration command according to the control coefficient.

As described above, according to the present embodiment, compensation can be performed in real time, it is possible to cope with a change in the characteristics of the specimen, and a specimen model and an accurate shaking table model are not required. It can be realized only by the provided sensor, and can compensate in real time for the fluctuation of the shaking table transfer characteristics due to the reaction force of the specimen.

[0067]

As described above, according to the present invention,
Compensation can be performed in real time, it can respond to changes in the characteristics of the specimen, and it does not require a specimen model or an accurate shaking table model, it can be realized only with the sensor provided in the existing shaking table, the reaction force of the specimen, etc. And a control device and a control method for compensating in real time for fluctuations in shaking table transfer characteristics caused by the above.

[Brief description of the drawings]

FIG. 1 is a control block diagram showing one embodiment of a shaking table according to the present invention.

FIG. 2 is a flowchart collectively showing a method of controlling a shaking table by a control device.

FIG. 3 schematically illustrates the principle of compensation of the shaking table transfer characteristic of the present embodiment.

FIG. 4 shows a configuration example of a conventional shaking table.

FIG. 5 schematically shows a control block diagram of a conventional shaking table.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Signal generator 2 Control calculation means 3 Reference signal generation means 4 Reference signal filter 5 Output signal filter 6 Identification means 101 Table 102 Bearing 103 Foundation 104 Shaker, 104a Piston 105 Acceleration measurement means 106 Control device 107 Specimen

Continued on the front page (72) Inventor Toshihiko Horiuchi 502, Kachidate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (72) Inventor Takao Konno 603, Kandamachi, Tsuchiura-shi, Ibaraki Pref.Industrial Machinery Systems Division, Hitachi Ltd. (72) Inventor Mitsuru Kageyama 4-640 Shimoseito, Kiyose-shi, Tokyo, Japan Inside Obayashi Gumi Technical Research Institute (72) Inventor Hideo Katsumata 4-640 Shimoseito, Kiyose-shi, Tokyo Japan, Ltd. Mitsuru 4-640 Shimoseito, Kiyose-shi, Tokyo F-term in Obayashi Corporation Technical Research Institute (reference) 5H004 GB20 HA09 HB09 JA05 JA12 JB15 KA32 KB16 KC24 KC28 KC45 LA12 MA12 MA14

Claims (7)

[Claims] 1. A table for mounting a specimen, a vibrator for vibrating the table, and a measuring means for measuring a motion state of the table, wherein a detection signal of the measuring means is fed back, and A vibration table control device that compares the fed back detection signal with a target command signal input from the outside and controls the vibrator based on the deviation thereof, comprising: Reference signal generating means having characteristics or a pre-identified shaking table transfer characteristic in a no-load state, capturing the command signal and generating a target reference signal of the shaking table output signal, Identification means for identifying a change in the shaking table transfer characteristic due to disturbance from the reference signal and the detection signal detected by the measuring means, and calculating a control coefficient to compensate for the identified change, A control operation means for correcting the command signal according to a control coefficient from the identification means. 2. An input / output signal of the reference signal generation means, an input signal of the identification means, and an input / output signal of the control operation means are unified into either an acceleration signal or a displacement signal. The control device for a shaking table according to claim 1, wherein: 3. The control apparatus according to claim 1, wherein a low-pass filter or a band-pass filter is provided for each of the two input signals to the identification means. 4. The control apparatus for a shaking table according to claim 3, wherein characteristics of a low-pass filter or a band-pass filter provided for each of the two input signals to the identification means match. 5. A table for mounting a specimen, a vibrator for vibrating the table, and measuring means for measuring a motion state of the table, wherein a detection signal of the measuring means is fed back, and A vibration table having a control device that compares the feedback detection signal with a target command signal input from the outside and controls the vibrator based on the deviation, wherein the vibration table of the target command signal is provided. Reference signal generating means having a transfer characteristic or a previously identified shaking table transfer characteristic in a no-load state, taking in the command signal and generating a target reference signal of the shaking table output signal, From the reference signal and the detection signal detected by the measuring means, to identify a change in the shaking table transfer characteristic due to disturbance, and to calculate a control coefficient to compensate for the identified change. Vibrating table, characterized in that it comprises a stage, and a control arithmetic unit for correcting the command signal according to the control coefficients from the identification means. 6. A feedback signal of a detection signal of a measuring means for measuring a movement state of a table, a comparison between the feedback detection signal and a target command signal input from the outside, and a control device based on a deviation thereof. In a method of controlling a shaking table that controls a vibrator, the shaking table has a shaking table transmission characteristic of the target command signal or a previously identified shaking table transmission characteristic of a no-load state. A reference signal to be a target of the output signal is generated by the reference signal generation means, and a fluctuation of the shaking table transfer characteristics due to disturbance is identified from the reference signal and the detection signal detected by the measurement means, and the identified fluctuation is compensated. Therefore, the control coefficient is calculated by the identification means, the command signal is corrected by the control calculation means according to the control coefficient, and the fluctuation of the shaking table transfer characteristic due to disturbance is obtained. And a calculation of a control coefficient for compensating for this variation are repeated, and a command signal to a control device of the shaking table is compensated using the latest control coefficient. . 7. A feedback signal of a detection signal of a measuring means for measuring a movement state of a table, a comparison between the feedback detection signal and a target command signal inputted from the outside, and a control device based on a deviation thereof. In a method of controlling a shaking table that controls a vibrator, the shaking table has a shaking table transmission characteristic of the target command signal or a previously identified shaking table transmission characteristic of a no-load state. A reference signal to be a target of the output signal is generated by the reference signal generation means, and a fluctuation of the shaking table transfer characteristics due to disturbance is identified from the reference signal and the detection signal detected by the measurement means, and the identified fluctuation is compensated. Therefore, the control coefficient is calculated by the identification means, and the command signal is corrected by the control calculation means in accordance with the control coefficient. Vibrating table control method of a signal and that the signal and compensation there are characterized in that it is unified to any one of the acceleration signal or displacement signal.