JPH11300278A - Apparatus for controlling twin vibrating tables - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain on table observation waves of performance equivalent to the case of one vibrating table by a method in which when vibrating tables are connected through a specimen and vibrated the transmission characteristics of the whole coupled system comprising the vibrating tables and vibrator are identified, characteristic compensation calculations are implemented on the basis of the transmission characteristics, and input waves are formed. SOLUTION: In an electric hydraulic vibrating table system which reproduces actual earthquake waveforms and investigates the strength of a specimen against earthquakes, the specimen 2 such as a bridge model is mounted between vibrating tables 1a, 1b, and an accelerometer 3 is fitted to each of the vibrating tables 1a, 1b. When each vibrating table 1a, 1b is vibrated by an electrohydraulic actuator 9, and a vibrating experiment is performed, an acceleration signal measured by each accelerometer 3 is input into a computer 6 through an amplifier 4 and an A/D converter. In the computer 6, the characteristic compensation calculations of input waves to be vibrated next are done, and a driving control signal to be vibrated next is input into the actuator 9 through a D/A converter 7 and a servo amplifier 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a twin shaking table controller. For example, the present invention relates to a twin shaking table control device applied to an electro-hydraulic shaking table system.

[0002]

2. Description of the Related Art With a test specimen mounted on a table serving as a shaking table, the purpose is to reproduce the seismic waveform actually observed at a meteorological observatory, etc., and to examine the strength of the test specimen against earthquakes. There was an electro-hydraulic shaking table system utilized. The shaking table controller used in this electro-hydraulic shaking table system needs to accurately reproduce the acceleration waveform of the seismic wave. The actual control method is to make the table observation wave follow the target waveform as much as possible. I was

FIG. 4 is an overall system diagram of a conventional shaking table controller.
Shown in As shown in the figure, a vibrating table (table) 1 is provided with a specimen 2 and an accelerometer 3 so that the vibrating body 1 can be vibrated by an electro-hydraulic actuator 9. Has become. Therefore, shaking table 1
The accelerometer 3 provided in the device measures an acceleration signal during the vibration experiment, and the measured acceleration signal is supplied to the amplifier 4, A / A
The data is taken into the computer 6 via the D converter 5.

The computer 6 performs a characteristic compensation calculation of the input wave to be excited next time, and outputs a signal to be excited next time via the D / A converter 7 and the servo amplifier 8 to the electro-hydraulic actuator 9.
And vibrates the shaking table 1. Since the behavior of the table 1 is controlled with six degrees of freedom (three translational components and three rotational components), the computer 6 has a six-dimensional arithmetic configuration.

[0005] The specific operation of the computer 6 will be described with reference to FIG. FIG. 5 shows a flowchart of the characteristic compensation calculation of the input wave. The contents of the operation are roughly classified into two types. One is an operation related to characteristic grasp excitation, and the other is an operation related to input compensation excitation.

[I. Calculation for Characteristic Excitation and Excitation] This calculation is for calculating transmission characteristics from the input to the exciter to the table response. An input acceleration signal is converted from time data to frequency data by Fourier transform 10, converted from acceleration to a displacement signal by two-time integration 11, and the displacement signal is subjected to inverse Fourier transform 12 to be input to a shaker. It becomes a displacement signal in the time domain. The vibrator 13 represents a system including a vibrator and a table.

[0007] The response acceleration signal in the time domain observed on the table is converted to frequency data by performing a Fourier transform 14, and a frequency response calculation 15 is performed from both of the input signals converted by the Fourier transform 10 to obtain a vibration. The transfer characteristics of the platform system are obtained. The transfer characteristics obtained here are generally in the form of a 6 × 6 matrix because the table is controlled with six degrees of freedom.

[II. Calculation for Input Compensation Excitation] This calculation uses the transfer characteristics obtained above to compensate for the characteristics of the input wave for excitation. First, an inverse characteristic calculation 17 of the transfer characteristic obtained above is calculated, and an initial input compensation calculation 19 is performed from both target wave data in the frequency domain obtained by performing a Fourier transform 18 on the target wave 28.

The obtained initial input compensation wave is subjected to a second-order integration 20 and an inverse Fourier transform 21 to generate an input signal to a vibrator. If the deviation 29 between the response acceleration signal in the table and the target wave 28 does not satisfy the determination 23, the obtained signal is subjected to the Fourier transform 24, and the input compensation 25 is repeatedly calculated to generate an input compensated wave.

[0010]

The above-mentioned conventional shaking table control device has one table, and the table is controlled with six degrees of freedom, so that it has a 6 × 6 matrix operation configuration. There is a problem that the method cannot be applied when the control target has six or more degrees of freedom.

[0011]

According to a first aspect of the present invention, there is provided a twin-shaking table control apparatus for solving the above-mentioned problems, in which a plurality of shaking tables are connected and vibrated via a test piece in advance. The transmission characteristic of the entire coupled system of the shaking table and the exciter connected via the specimen is identified, and the input wave is generated by performing the characteristic compensation calculation of the input wave based on the transmission characteristic. .

[0012]

Embodiments of the present invention will be described below in detail with reference to embodiments shown in the drawings. Embodiment 1 FIG. 1 shows a twin shaking table control apparatus according to a first embodiment of the present invention. FIG. 1 is a conceptual diagram of a vibration control system including a specimen mounted over two vibrators (tables).

As shown in FIG. 1, a shaking table 1a and a shaking table 1
b, the specimen 2 is mounted over the vibration table 1a, and each of the vibrating tables 1a and 1b is provided with an accelerometer 3 respectively.
Each of the vibrating tables 1a and 1b can be vibrated by an electrohydraulic actuator 9. Therefore, the shaking table 1a,
When a vibration experiment is performed by vibrating the electrohydraulic actuator 9 with the electrohydraulic actuator 9, the response waves observed at the vibrating tables 1 a and 1 b are easily affected by the vibration behavior of each other via the test piece 2. . As the specimen 2, for example, a bridge model is used.

An acceleration signal measured by the accelerometer 3 of each of the vibrating tables 1a and 1b passes through an amplifier 4 and an A / D converter 5,
The data is taken into the computer 6. The computer 6 performs a characteristic compensation calculation of the input wave to be excited next time, and a signal to be excited next time is input to the electro-hydraulic actuator 9 via the D / A converter 7 and the servo amplifier 8, and the vibration table 1a, Vibrate 1b.

[Embodiment 2] FIG. 2 shows a twin shaking table control apparatus according to a second embodiment of the present invention. FIG. 2 is a configuration diagram showing an analysis model at the time of grasping the characteristics of the twin table used at the time of confirming the analysis. In this embodiment, the configuration of the vibration control system of the first embodiment described above is represented as a specific analysis model. In FIG. 2, each block indicates a set of governing equations constituting the element.

As shown in FIG. 2, input signals 30a, 30a
b denotes input control panels 31a and 31b, and each of the vibrators (x,
are converted into command signals to the three directions (y, z) 34a, 34b, and the servo control boards 32a, 32b, the servo valves 33a, 33
3b, the table 36 via the three-dimensional joints 35a and 35b.
a and 36b are transmitted as excitation force. Here, since the specimen 37 is interposed between the two tables 36a and 36b, the two tables 36 are passed through the specimen 37.
Vibration is transmitted to a and 36b mutually.

As described above, the two tables 36a and 36b
When a vibration is applied to the vibration control device including the specimen 37 mounted over the two
Since a and 36b are coupled through the rigidity of the specimen 37, the transfer characteristics of only the table 36a or only the table 36b are measured, and the reflection on the input wave is calculated. Control to match the waves is very difficult. Therefore, in the present invention, the transfer characteristics of the coupled system of the tables 36a and 36b including the characteristics of the specimen are measured, and the results are reflected in the compensation calculation of the input wave.

That is, the input signals 30a and 30b shown in FIG.
Is a random signal of a total of 12 components (6 components + 6 components) so that the respective tables 36a and 36b can grasp and excite characteristics with 6 degrees of freedom. In this way, the random input signals of 12 components are simultaneously inputted, and the sample 37 is obtained from the 12 output signals 38a and 38b obtained at that time as the transfer characteristics of a generally well-known multi-input multi-output system. The transfer characteristics of the coupled system of the included tables 36a and 36b can be identified.

There are various methods for identifying the transfer characteristic, but the method based on the FFT method is as follows. As shown in FIG. 6, the response of a multi-input / output system composed of n inputs and m output points is given by equation (1).

[0020]

(Equation 1)

[0021] Here, Y _i: i-th output of the spectrum X _j: j-th input spectrum H _ij of: transmitting between ij functions N _i: noise measured by the i-th output point

Thus, the transfer function that minimizes the measurement error is given by equation (2). [GYX] = [H] [GXX] + [Z] (2) Here, [GYX]: cross spectrum matrix between m × n inputs and outputs [GXX]: cross spectrum matrix between n × n inputs [H]: mxn transfer function matrix [Z]: Cross-spectral matrix of noise By performing signal averaging, [Z]
Can be made sufficiently small, and finally, the transfer function is obtained by Expression (3).

[H] = [GYX] [GXX] ^-1 ...
(3) However, when calculating the inverse matrix of [GXX] in equation (3), if there is a correlation between input signals, [GXX]
Are not independent, and the determinant of [GXX] becomes 0 and the inverse matrix cannot be calculated. Therefore, it is necessary to use a signal having a coherence function of 0 for each input signal. Using the transfer characteristics thus obtained, the characteristic compensation calculation of the input wave was performed according to the procedure shown in FIG. 5 described above.

The compensation calculation procedure is the same as that of the conventional shaking table, but the calculation scale is different and the compensation calculation in the twin table system is a 12 × 12 matrix. Here, the input waves specifically used in the simulation are three-directional components of the natural seismic wave, as shown in FIG. FIG. 3 shows a response spectrum of the target wave and the bench observation wave. When the calculation of the characteristic compensation was performed three times, a simulation result in which the target wave and the bench observation wave coincided was obtained.

[0025]

As described above in detail, the twin shaking table control apparatus according to the first aspect of the present invention is configured such that when a plurality of shaking tables are connected and vibrated via the test pieces, Identifies the transfer characteristics of the entire coupled system of the shaking table and the exciter achieved through, performs the input wave characteristic compensation calculation based on the transfer characteristics, and generates the input wave. A bench observation wave with the same performance as that of the shaking table shaker can be obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a vibration control system configuration including a specimen mounted over two vibration tables (tables).

FIG. 2 is a configuration diagram showing an analysis model at the time of grasping a twin table characteristic used at the time of confirming by analysis.

FIG. 3 is a graph showing response spectra of a target wave and a table observation wave.

FIG. 4 is an overall system diagram of a conventional shaking table controller.

FIG. 5 shows a flowchart of a characteristic compensation calculation of an input wave.

FIG. 6 is an explanatory diagram showing a response of a multi-input / output system including n inputs and m output points.

[Explanation of symbols]

 1, 1a, 1b Shaking table 2 Specimen 3 Accelerometer 4 Amplifier 5 A / D converter 6 Computer 7 D / A converter 8 Servo amplifier 9 Electro-hydraulic actuator

Claims (1)

[Claims] 1. When a plurality of shaking tables are connected via a specimen and vibrated, the transfer characteristics of the entire coupled system of the shaking table and the vibrator connected via the specimen are identified in advance. A twin shaking table control device, wherein the input wave is generated by performing a characteristic compensation calculation of the input wave based on the transfer characteristic.