JPS63180744A - Vibration controller - Google Patents

Abstract

PURPOSE:To reduce the dead zone of controlling force through lessening frictional force by using a hydraulic bearing which generates support-force in the direction of gravity and lightening the weight of a movable mass added to a rolling bearing. CONSTITUTION:A hydraulic bearing 12 is provided between a movable mass 1 and a vibration body 4, and high pressure operating oil 13 is supplied from an oil pressure source 14. Because of this, if the frictional force of the oil pressure bearing 12 portion could be ignored, the frictional force in this instance, for example, when operating oil pressure force or the like is regulated so that support force may become 9/10 of the weight of the movable mass 1, could even make the frictional force in the case of the oil pressure bearing 12 having been used, abt. 1/10 of the old one. Thus, the size of frictional force can be ignored although the movable mass equal to that of the old vibration controller is used. Accordingly, the weight of the movable mass 1 added to a rolling bearing 11 is lightened, and the dead zone of control can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration control device for reducing the vibration of a structure such as an elevated road, and particularly to a method for reducing the dead zone of the control force.

[Conventional technology]

Mass dampers are generally used to reduce vibrations generated in vibrating bodies. Figure 2 shows an example of this. In the figure, 11) is a movable mass that is supported by a bearing aυ and is movably attached to the vibrating body (4) via a spring (2) and an actuator (3). There is. (5) is an accelerometer that detects the vibration speed of the vibrating body (4) through the integrator (7) l of the controller (6), and uses the power amplifier (8) to adjust the vibration speed to the actuator (3). It generates a proportional and opposite control force. (9) is a fixed core.

The actuator (3) is configured together with the movable core α1.

FIG. 3 explains the operation of the mass damper. 9M in model diagram
, is the mass of the vibrating body (4), and , is the spring constant.

co is the attenuation constant and 2M2 is the mass of the mobile mass i fi+.

K2 is the spring constant of the mass damper spring (2). Here, I, t - displacement rx2 of the vibrating body (4) and movable mass 111
Taking the displacement of , the equation of motion becomes as follows.

M2x2+ plus 2(x2-x,)v
(2) In the conventional mass damper, a control force (2) proportional to the vibration velocity and viscosity of the vibrating body (4) is generated in the following form, assuming that the gain constant is Cm.

7-6↓ ・・・・・・Equation (3) (
3) Substituting I in formula (1) yields the following.

Ml;, + (co 1 cm) 1 x 1 + 2 (I, -
x2) Mouth F... (4) From equation (4), the apparent damping k of the vibrating body (4) can be increased from Co to (co 1 cm) by applying control in the conventional mass damper. It can be seen that an effective vibration reduction effect is obtained.

[Problem that the invention seeks to solve]

The size of the movable mass that makes up a mass damper is generally a few percent of the mass of the vibrating body, but if the vibrating body itself is a huge structure, the movable mass can be as large as 10 ToN or more. . In such cases, horizontal rolling bearings are often used to move the movable mass smoothly, but as the size of the moving mass increases, friction in the rolling bearings becomes a problem.

For simplicity, assume that this friction is Coulomb friction.

When the weight of the movable mass is W and the coefficient of friction due to the rolling bearing is μ, the frictional force P is expressed by the ninth-order equation.

P=μW (5
) Also, this frictional force P is shown in Equation 9 (3) and acts in the opposite direction E to the control force that is intended to act on the movable mass, so
The control force when there is frictional force is as follows.

Figure 5 shows the vibration velocity x1E in the case of frictionless equation (3).
FIG. 6 is a graph of control force versus vibration speed x1 in the case of equation (6) in which friction is taken into account.

From Fig. 6, in the range of l cnlxll<Hp l.

Due to frictional force, the movable mass does not move, creating a so-called dead zone where no control force is generated, and the vibration level cannot be controlled below this level.

Problems have arisen in that the control system becomes unstable.

This invention was made to solve these problems, and aims to reduce the weight of the movable mass added to the rolling bearing that causes frictional force, and to obtain a vibration control device with a small dead zone.

[Means for solving problems]

The vibration control device according to the present invention uses a hydraulic bearing that generates a supporting force in the direction of gravity to reduce the burden of movable mass added to the rolling bearing.

E is applied to reduce the frictional force.

[For production]

In this invention, most of the weight of the movable mass is carried by a hydraulic bearing with extremely low friction that has metal contact parts, so the frictional force can be greatly reduced, the dead zone is completely eliminated, and the vibration reduction effect is even more effective. can be made thicker.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

11) to αυ are completely the same as in the above conventional device. α2 is a hydraulic bearing provided between the movable mass and the vibrating body, and is supplied with high pressure hydraulic oil (2) from a hydraulic source θ4.

Now, the effective cross-sectional area of the hydraulic Bearisig is A1 hydraulic oil pressure fq
Then, the supporting force R generated in the hydraulic bearing is as follows.

R-Aqoo"-(7) Therefore, assuming that the frictional force of the hydraulic bearing part can be ignored, the frictional force Q in this case is as follows.

Q--μ(w = R>...
・(8) For example, if the hydraulic oil pressure is adjusted so that the supporting force R is 9/l of the weight W of the movable mass, the frictional force Q when using a hydraulic bearing can be reduced to the conventional frictional force. P's/,. It is also possible to set it as a degree.

In this way, the vibration control device configured as shown in Fig. 1 uses the same movable mass as the conventional vibration control device, but
The magnitude of the frictional force can be made negligible.

In addition, since the load applied to conventional supporting devices such as rolling bearings, such as restraining the direction of movement of the movable mass, is reduced, the life of these devices can be significantly extended.

〔Effect of the invention〕

As explained above, this invention uses an easy-to-implement method of supporting part of the weight of a movable mass with hydraulic bearings, which effectively reduces the effects of frictional forces that adversely affect vibration control at low vibration levels, and This has the effect of improving the vibration reduction effect of the control device and extending the life of rolling bearings, etc. that support the weight of the movable mass.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, Fig. 2 shows a conventional vibration control device, Fig. 3 shows the principle of the vibration control device, and Fig. 4 shows control when there is no friction. FIG. 5, a diagram showing force characteristics, is a diagram showing control force characteristics when frictional force is taken into consideration. In the figure, il+ is a movable mass, (2) is a spring, (3) is an actuator, (4) is a vibrator, (5) is an accelerometer,
(6) is a controller. Note that the same reference numerals in each figure indicate the same or similar parts.

Claims (1)

[Claims] a vibration detection means for detecting the vibration of a vibrating body that vibrates in response to external force; a movable mass that reciprocates in the vibration direction of the vibrating body; A hydraulic bearing that generates a supporting force, an actuator fixed to the vibrating body and driving the movable mass, and controlling the actuator so as to output a control force proportional to the vibration speed of the vibrating body detected by the vibration detection means. A vibration control device comprising: a controller for controlling vibrations;