JPS61290252A - Vibration controller - Google Patents

Abstract

PURPOSE:To effectively suppress vibration of an oscillator, by selecting a component of relatively low frequency of the vibrative speed of the oscillator and applying control force in accordance with said frequency component to the oscillator by an actuator. CONSTITUTION:A vibrative speed of an oscillator 4 is obtained by detecting a signal in an accelerometer 5 to be integrated by an integrator 7. Of the obtained vibrative speed, only a component of frequency lower than a predetermined frequency is selected by a low-pass filter 11, and a controller gives in control force, in proportion to the selected signal, a vibration of reverse phase to the oscillator 4 by an actuator 3. The controller, preventing a component of high frequency in the vibrative speed from participating in a control of the actuator, eliminates a condition of vibration that it can not be prevented by saturating the actuator with control force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration control device for reducing vibrations of structures such as elevated roads, and particularly to prevention of out-of-band noise in external forces.

(Conventional technology) -To reduce vibrations caused by the vibrating body in the crotch.

A mass damper is used. Figure 4 shows an example of this. In the figure, (1) is a movable mass.

Vibrating body (4) via spring (21 and actuator (3))
) is movably attached. (5) is an accelerometer, which detects the vibration speed of the vibrating body (4) using the integrator (7) of the controller (6), and uses the power amplifier (8) to control the actuator (3) so that the vibration speed is proportional to the vibration speed. It generates a control force in the opposite direction. (9) is a fixed core, which together with the movable core +11 constitutes an actuator (3).

Figure 5 is a model diagram explaining the operation of a mass damper.
l is the mass I of the vibrating body (11) Kr is the spring constant ec6 is the damping constant 2M is the quality t of the movable mass (1), is the spring constant of the mass damper spring (2), where X, f
If we take the displacement of the vibrating body (4) and Xt to be the displacement of the movable mass (11), the equation of motion becomes as follows.

MI Xs + C, +l Xs + Kr L
+ Km (Xt Xs 1=F-V
・・・・・・・・・－・・−・・・・・・・・・・・・・
・・・・・・・・・・・・・・・(11Mt L + K
t IX* XI) =V・−・・・・−・・・・−
(2) In the conventional mass damper, a control force V proportional to the vibration velocity X1 of the vibrating body (41) is generated in the following form, assuming that the gain constant is Cm.

v=CmXl・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・(3)'Mx
s + I Co +Cm) Xi + to + XI+
Kt (X+-X,)=F ・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
... (4) From equation (4), in the conventional mass damper, by applying control sound, the apparent damping t, C of the vibrating body (4)
It can be seen that an effective vibration reduction effect is obtained by increasing the distance from 0 to (Co+0m).

[Problem that the invention seeks to solve]

Considering that the movement of the vibrating body to be controlled by the mass damper is close to a sine wave, equation (3) can be written as a linear equation.

V=Cm-W-X!・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・(5) From equation (5), if the displacement XI of the vibrating body is the same at high frequencies (large W), a larger control force is required for W. I understand that.

In particular, when the controlled object is a complex structure such as an elevated road, it often has many natural frequencies up to high frequencies.
These high-frequency vibrations often result in localized vibrations due to the effects of road joints, etc.If these vibrations are excited, they can reach large vibration levels, which can saturate the actuator of the mass damper. There was a point.

This invention was made to solve this problem, even when there is an external force due to high-frequency local vibration that does not require vibration control.

The object of the present invention is to obtain a vibration control device that effectively reduces vibrations in a necessary frequency range without saturating the control force of an actuator.

[Means for solving problems]

The vibration control device according to the present invention includes a low-pass filter that cuts off frequency components higher than a preset frequency in the controller, and a signal that cuts off high-frequency components of the vibration speed of the vibrating body. The control force is generated by the actuator.

[Effect]

In this invention, the low-pass filter blocks unnecessary high frequency components of the vibration speed of the vibrating body, so the control force of the actuator is saturated due to the large noise of the vibration level at these high frequencies. This prevents it from being put away.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.
σG is exactly the same as in the conventional device. αυ is the controller (
6) The low-pass filter provided in 1 can be realized by, for example, a filter having the following frequency characteristics.

GIS) = 110 years old...
(6) Figure 2 shows the gain characteristics of the filter expressed by equation (6).If the cutoff frequency is set to wo in advance, then at a frequency 10 times this It can be seen that the gain is approximately 1/10 (-20 dBl).

Therefore, in the vibration control device configured as shown in FIG. That frequency is the cutoff frequency W of the 9 filter
If it is about 10 times thicker than 0, the control force will be about 1/10 of that before using the filter.In the end, the influence of this frequency component on the control force can be ignored.
The figure relates to another embodiment of the present invention, and shows the gain percentage of a filter that uses a plurality of filters shown in FIG. 2 in series to have even sharper high-frequency cutoff characteristics. Such a low-pass filter can be realized, for example, by a filter having the following transfer function.

G (81.=, is<-”knee)・・・・・・・・・
...+7+1-i 1 + S/Wi It is clear that by using such a filter, the influence of high-level noise at high frequencies on the control force can be further reduced.

〔Effect of the invention〕

As explained above, this invention uses a very easy-to-implement method in which a low-pass filter is provided all around the controller, and controls the actuator of the vibration controller using high frequency noise contained in the external force. Effectively suppresses force saturation.

This has the effect of making the hardware of the vibration control device economical.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing the gain characteristics of a low-pass filter. Figure 3 is a diagram showing the gain characteristics of other low-pass filters.
Fig. 4 is a diagram showing a conventional vibration control device, and Fig. 5 is a diagram showing the principle of the vibration control device. (5) is an accelerometer, and (6) is a controller. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] a vibration detection means for detecting the vibration of a vibrating body that vibrates in response to an external force; a movable mass that moves back and forth in the vibration direction of the vibrating body; an actuator that is fixed to the vibrating body and drives the movable mass; A controller for controlling the actuator so as to output a control force proportional to a signal that passes only a frequency component lower than a preset frequency among the vibration speed of the vibrating body detected by the means. Vibration control device.