JP3495595B2 - Shaking table controller - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a shaking table control apparatus applied to a shaking table system, and is capable of matching a response waveform to a target waveform in a short time. It is devised so that it can be done. 2. Description of the Related Art With a test specimen mounted on a table serving as a shaking table, a target waveform (for example, an earthquake waveform actually observed at a meteorological observatory or the like) is reproduced and the test specimen is reproduced. There is a vibrating body system used for examining the strength or the like of an input waveform (earthquake). A shaking table control device used in this shaking table system needs to accurately reproduce a target wave (eg, an acceleration waveform of a seismic wave). As an actual control method, a response waveform (on a shaking table) is used. (Observed and detected waveforms) follow the target waveform as much as possible. FIG. 3 is an overall system diagram showing a conventional shaking table controller. As shown in FIG. 1, a specimen 2 is mounted on a shaking table (table) 1, and the shaking table 1 is activated by an electrohydraulic actuator (vibrator) 9 operating.
Vibrates to excite the specimen 2. During a vibration experiment using the shaking table 1, the acceleration of the shaking table 1 is detected by the accelerometer 3, and the detected acceleration signal α (d ² Y / dt ² or d ² X / d
t ² ) is amplified by the amplifier 4 and taken into the computer 6 via the A / D converter 5. The acceleration signal α represents a response waveform of the shaking table 1. The computer 6 performs a compensation calculation for the input wave to be excited next time, and outputs a shaker command signal β (X
(T) or X ₁ (t)) is amplified by the servo amplifier 8 via the D / A converter 7 and then input to the actuator 9, which then outputs the signal based on the input shaker command signal β. It operates to excite the shaking table 1. Here, the specific calculation contents in the computer 6 will be described with reference to FIG. 4 which is a flowchart of the compensation calculation of the input wave. There are two types of arithmetic operations. One of them is a calculation at the time of vibration when grasping a transfer characteristic from an input to the vibrator (actuator 9) to a response of the table (vibration table 1) (characteristic grasp vibration). In the characteristic grasp vibration calculation, input (generation) 27
Is converted from time data to frequency data by the Fourier transform 10, converted from an acceleration signal to a displacement signal by the second-order integration 11, and the displacement signal is subjected to an inverse Fourier transform 12 to be input to a shaker. It becomes a displacement signal in the time domain. The vibration 13 represents a system including a vibration machine and a table. The response acceleration signal in the time domain observed on the table is converted to frequency data by performing a Fourier transform 14, and the response frequency data obtained by the Fourier transform 14 and the input signal converted by the Fourier transform 10 By performing the frequency response calculation 15 based on the input frequency data of (1), the transfer characteristic G of the shaking table system is obtained. The transfer characteristic G obtained here has a 6 × 6 matrix configuration since the table is generally controlled with six degrees of freedom (three translational components and three rotational components). It should be noted that the result of the frequency response calculation 15 is determined by the determination 16, and the input wave is changed when the frequency is poor, and when the frequency is good, the transfer characteristic G of the shaking table system obtained here is changed by the input compensation excitation described below. Is used for the calculation of Another operation is an operation for compensating an input wave for excitation using the transfer characteristics obtained as described above (input compensation excitation). In the input compensation excitation calculation, first, an inverse characteristic operation 17 of the transfer characteristic obtained by the above-described characteristic grasp excitation is calculated, and the calculated data and a frequency domain obtained by performing a Fourier transform 18 on the target wave 28 are calculated. An initial input compensation calculation 19 is performed based on the target wave data. 2nd integration 2
0 and inverse Fourier transform 21 are performed to generate an input signal to the vibrator, and the input signal is used to vibrate 22. After determining 23 a signal obtained from a deviation 29 between the response acceleration signal of the table and the target wave 28,
Fourier transform 24, repeatedly calculating input compensation 25,
Generate an input compensation wave. [0015] As described above, in the conventional control method, when the excitation by the generated fixed-time input wave ends, an input wave to be excited next time is generated.
Since this is a so-called discrete excitation control method for executing a compensation program, a complete input signal reproduction requires a plurality of compensation calculations, which takes a considerable amount of time. An object of the present invention is to provide a shaking table control device capable of causing a response waveform to coincide with a target waveform in a short time in view of the above prior art. According to the present invention, there is provided a vibration table on which a specimen is mounted, and a vibration table which is operated based on an input of a vibrator command signal. A vibrator that vibrates, an accelerometer that detects the acceleration of the shaking table and outputs an acceleration signal, and performs a compensation operation so that a response waveform represented by the acceleration signal becomes equal to a preset target waveform. And a calculator for obtaining and outputting the shaker command signal, wherein the calculator calculates an error between a sine wave having the same fundamental wave component as the target waveform and the acceleration signal. An error signal is obtained, and a Filtered-χ LMS algorithm operation is performed using a reference signal that is a rectangular wave having the same fundamental wave component as the sine wave and the error signal so that harmonic components of the error signal converge to zero. By doing Seeking vibrator command signal, a vibrator command signal obtained and outputting the vibrator. Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the same reference numerals are given to portions that perform the same functions as those of the related art, and overlapping descriptions will be omitted. FIG. 1 is an overall system diagram showing a shaking table control device according to an embodiment of the present invention. As shown in the figure, the acceleration signal α measured by the accelerometer 3 during the vibration experiment using the shaking table 1 is amplified by the amplifier 4 and is converted by the A / D converter 5.
Is taken into the computer 16 via the. The computer 16 performs an input wave compensation operation. The specific calculation contents are as follows. That is, the compensation operation that becomes the input wave is one of the adaptive control methods, Filtered- 適 応
This is performed based on the LMS algorithm 31. Filtered-χ LMS algorithm 31
Has a function of sequentially updating a compensation filter coefficient required for shaking table control based on a steepest descent method so as to minimize a root-mean-square value of an error signal from a reference signal and an error signal. LSM indicates least mean spuare (least mean square algorithm). Specifically, the following equation is used. σ ² = αχ (n) ² + (1−α) σ ² ·· (1) W (i) = W (i) + (2u / Nσ ² ) · ε (n) χ (n-1) ··· (2) where χ (n−1) is an input signal i-point before the current point n,
ε (n) is the error signal at the current point n, W (i) is the i-th coefficient of the impulse response, σ ² is the average power of the input signal, α is the weight coefficient for estimating the average power, u is the step size, and N is the number of taps. It is. The error signal input to the Filtered-χ LMS algorithm 31 includes an acceleration signal α detected and observed by the accelerometer 3 installed on the shaking table 1 and a sine wave 33 having the same fundamental wave component as the target wave. Is the difference from the signal output via the delay element 32. Also, Filtered-χ
The reference signal input to the LMS algorithm 31 is a rectangular wave 30 having the same fundamental wave component as the target sine wave. The signal (vibrator command signal β) output through the compensation filter generated by the Filtered-３１ LMS algorithm 31 passes through the D / A converter 7 and the servo amplifier 8
And is sent to the actuator 9. Actuator 9 operates based on the input shaker command signal β,
The shaking table 1 is vibrated. The shaking table control apparatus according to the present embodiment, which operates as described above, includes a discrete excitation method (conventional method) in which excitation is temporarily stopped and a compensation wave for the next excitation is calculated. However, there is an advantage that the compensation wave can be continuously output until the error signal converges to zero. FIG. 2 shows an outline of the operation of the computer 16 of the shaking table controller according to the present embodiment. This control device realizes a sinusoidal response of a single frequency component containing no harmonic component on the shaking table, but as a reference wave, a rectangular wave 30 having a frequency component whose fundamental component is to be reproduced. Is used. When the frequency analysis of the rectangular wave 30 is performed, in addition to the frequency component f _{1 serving} as a fundamental wave component, a component that oscillates at an integral multiple of the fundamental wave component appears as a harmonic component. The sinusoidal wave 33 having a single frequency component synchronized with the rectangular wave 30 is passed through the delay element 32, and the difference between the sinusoidal wave 33 and the vibration actually observed by the vibrating table 1 is calculated to obtain an error signal. If a harmonic component is included in the observed signal, the error signal also includes a harmonic component signal. Therefore, in the Filtered-χ LMS algorithm 31, the harmonic component of the error signal converges to zero in the LSM algorithm 34 based on the square wave 30 as the reference signal and the error signal (1) (2). A compensation filter 35 is generated based on the expression (1), and the rectangular wave 30 as a reference signal is processed by the filter to be a compensation wave (vibrator command signal β), which is output from the computer 16. As described above in detail with the embodiments, according to the present invention, the shaking table on which the specimen is mounted and the vibrator operated based on the input shaker command signal are operated. A shaker that shakes the shaking table, an accelerometer that detects the acceleration of the shaking table and outputs an acceleration signal, so that a response waveform represented by the acceleration signal is equal to a preset target waveform. A shaking table control device comprising: a calculator that performs compensation calculation to obtain and output the shaker command signal; wherein the calculator includes a sine wave having the same fundamental wave component as the target waveform and the acceleration signal. Find the error signal that is the error,
The excitation is performed by performing a Filtered-χ LMS algorithm operation using a reference signal that is a rectangular wave having the same fundamental wave component as the sine wave and the error signal so that the harmonic component of the error signal converges to zero. The apparatus command signal is obtained, and the obtained shaker command signal is output to the shaker. As described above, in the present invention, Filtered-χ L
By using a rectangular wave whose fundamental wave component matches the frequency component to be reproduced as a reference signal to be input to the MS algorithm, the signal output from the computer includes a component for removing harmonic components. Thus, a sine wave having a single frequency component can be reproduced. Further, in the shaking table control device of the present invention, since it is possible to continuously compensate for the on-table reproducible wave, the target wave and the response wave can be matched in a short time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram showing a shaking table control device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing a calculation outline of a computer of the shaking table control device according to the embodiment of the present invention. FIG. 3 is an overall system diagram showing a conventional shaking table controller. FIG. 4 is an explanatory diagram showing a calculation outline of a computer of a conventional shaking table controller. [Description of Signs] 1 Shaking table (table) 2 Specimen 3 Accelerometer 4 Amplifier 5 A / D converter 6, 16 Computer 7 D / A converter 8 Servo amplifier 9 Actuator (vibrator) α Acceleration signal β Exciter command signal

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-114930 (JP, A) JP-A-7-223444 (JP, A) JP-A-7-27664 (JP, A) JP-A-60-1985 63676 (JP, A) JP-A-11-304637 (JP, A) JP-A-2-38610 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 7/02 B06B 1 / 00 B06B 1/02 B06B 1/18

Claims (1)

(57) [Claims 1] A shaking table on which a specimen is mounted, a vibrator for vibrating the shaking table by operating based on an input of a vibrating machine command signal, An accelerometer that detects the acceleration of the shaking table and outputs an acceleration signal, and performs a compensation operation so that a response waveform represented by the acceleration signal is equal to a preset target waveform, and calculates the shaker command signal. In the shaking table control device comprising a calculator that obtains and outputs, the computer obtains a sine wave having the same fundamental wave component as the target waveform and an error signal that is an error between the acceleration signal and the sine wave. A shaker command signal is obtained by performing a Filtered-χ LMS algorithm operation using a reference signal that is a rectangular wave having the same fundamental wave component and the error signal so that harmonic components of the error signal converge to zero. Asked,
A shaking table control device, which outputs the obtained shaker command signal to the shaker.