JPH06241276A - Damping device of tower - Google Patents

Abstract

PURPOSE:To provide a simply structured damping device that is able to control a tower vibration in a building easily and accurately too. CONSTITUTION:A steel plate 5 is attached to four sides at the upper part of a tower A. In addition, four electromagnets 1 to 4 to be opposed in keeping a specified gap each, two acceleration sensors 6, 7 detecting any swing in both X- and Y-axis directions of the tower A, and a control circuit 8 controlling an exciting current of the electromagnet on the basis of each signal out of these sensors are all installed in each of these steel plates 5. In this constitution, this control circuit 8 outputs a signal, killing the vibration detected by the sensor, whereby a current amplified by a power amplifier 9 flows into the electromagnet, where the set gap in a gap with the tower A becomes enlarged, so that a swing in the tower A is controlled by electromagnetic attraction against the steel plate 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping device which suppresses the shaking of a tower installed mainly in a building by an active method.

[0002]

2. Description of the Related Art As a tower installed in a building, for example, there is a tower for drawing electric wires. Since this drawing tower is independent from the building, it easily shakes when the ground vibrates, and if the shaking is large, problems such as disconnection of the electric wire during drawing occur. Therefore, in order to avoid such troubles, a passive vibration isolation method is adopted in which the vibration transmitted from the ground to the structure is absorbed by the damper,
Also, as another method, an active vibration control method using a mass damper is considered.

The damping method using a mass damper includes a passive method in which the mass is naturally swung by the principle of a pendulum, an active method in which the movement of the mass is optimally controlled by an actuator to obtain a large damping effect in a wide frequency range, There are three hybrid methods that combine the passive method and the active method, and these are described in detail in Ishikawajima Harima Technical Report Vol. 31, No. 2.

[0004]

The passive vibration isolation method described above is not very effective and cannot cope with large shaking such as during an earthquake.

The passive mass damper cannot be expected to have a great effect if the vibration characteristic of the object to be damped (tower) changes or the mass of the mass is smaller than that of the tower. Also, in this method, the mass does not move unless the tower shakes to some extent.

On the other hand, the active type and hybrid type mass dampers can be said to be effective damping devices when there is no fixed surface around the tower, but the mechanism is very complicated, and it is a small size such as a drawing tower installed in a room. Not suitable for the tower.

[0007] Therefore, it is an object of the present invention to provide a vibration damping device which is suitable for use in a small tower in a building, is simple and small, and has excellent vibration damping performance.

[0008]

The vibration damping device of the present invention for solving the above-mentioned problems is supported by a ferromagnetic material mounted on the opposite side surfaces of a tower and a building having a higher self-sustaining stability than the tower. And an electromagnet that faces each of the ferromagnetic bodies with a predetermined gap maintained therebetween, a sensor that detects a shake of the tower, and a circuit that controls an exciting current of the electromagnet based on a signal from the sensor. This device is installed at least in the upper part of the tower, and the attraction force of the electromagnet is made to act on the ferromagnetic material in the direction of returning the deflection of the tower under the control of the exciting current control means.

When the tower is flexible and causes high-order self-excited vibrations, similar devices are installed not only on the upper part of the tower but also at several places, and the installation position of each device is controlled according to the deviation of the installation point. It is recommended to perform vibration control.

[0010]

When the shake of the tower is detected by, for example, an acceleration sensor, the direction and speed of the shake can be known. Therefore, the control circuit generates a signal for canceling the vibration detected by the sensor to drive the electromagnet. The driving is performed on the electromagnet on the side where the set gap with the ferromagnetic material is large, and the electromagnetic attraction force acting on the ferromagnetic material causes the tower to be retained, thereby producing a vibration damping effect.

In this way, when there is a fixed surface around the tower, by installing an electromagnet on the fixed surface, it is possible to easily suppress the tower vibration with a simpler device than the active or hybrid type mass damper.

Further, since it is only necessary to provide a ferromagnetic material and a sensor on the tower side, the tower can be installed without limitation at locations other than the upper part of the tower, and for flexible towers, vibration control at several locations can be used to achieve high-order self-control. The damping performance can be expected to be better than before, such as the fact that the excited vibration component can also be canceled.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the vibration damping device of the present invention. In the figure, A is a tower, B is a building, and C is an arm attached to the building. The tower A has a rectangular cross section, and the iron plate 5 is attached to each side surface of the upper part of the tower. Also, each iron plate 5
The electromagnets 1, 2, 3 and 4 are faced to each other with a predetermined gap maintained. The four electromagnets 1 to 4 are all supported by the arm C.

At the top of the tower A, as shown in FIG. 1B, an acceleration sensor 6 for detecting shake of the tower in the X-axis direction and an acceleration sensor 7 for detecting shake of the tower in the Y-axis direction are provided. There is. Further, the acceleration sensor 6,
A control circuit 8 is provided which inputs a signal from 7 and sends an excitation signal to the electromagnets 1, 2 or 3, 4. Since the control circuits for the X-axis direction and the Y-axis direction have the same configuration, only the control circuit for the X-axis direction is shown in the figure.

In the vibration damping device thus constructed, when the tower A is stationary, the electromagnets 1 to 4 are all in the non-excited state. Now, when the tower A swings to the right in the figure, a signal is output from the acceleration sensor 6 to generate a signal for causing the electromagnet 1 to generate an attractive force corresponding to the sensor output in the control circuit 8. Signal to power amplifier 9
The electric current amplified in step 3 flows through the electromagnet 1 and the tower A is pulled back to its original position. Even when the tower A swings in another direction, the tower is pulled back by the same action, and the swing becomes small.

FIG. 2 shows a vibration damping device effective for a flexible tower. In this device, the same device as that described in FIG. 1 is provided at the upper part of the tower and at two positions in the middle of the height direction, and vibration suppression control is performed at the installation point of each device according to the shake of the installation point. . Therefore, it is possible to cope with self-excited vibration, and the vibration can be sufficiently suppressed even in a flexible tower.

[0017]

As described above, since the vibration damping device of the present invention is configured to actively suppress the vibration of the tower by using the electromagnet, it is simple, and the drawing tower or the like to be installed in the building. Can be easily and effectively prevented.

Further, since the same device can be mounted on the same tower without being restricted by a plurality of units to perform high-level vibration damping, stationary stability can be enhanced even in a flexible tower, and the vibration of the tower is caused. Helps prevent problems.

[Brief description of drawings]

FIG. 1A is a front view showing an example of a vibration damping device of the present invention. FIG. 1B is a plan view of the same.

FIG. 2 is a front view of another embodiment in which vibration damping control is performed at several points.

[Explanation of symbols]

 1, 2, 3, 4 Electromagnet 5 Iron plate 6, 7 Acceleration sensor 8 Control circuit 9 Power amplifier A Tower B Building C Arm

Claims (1)

[Claims] 1. A ferromagnet attached to opposite side surfaces of a tower, and an electromagnet supported by a building having a higher self-sustaining stability than the tower so as to face each of the ferromagnets with a predetermined gap maintained therebetween. A sensor for detecting shake of the tower and a circuit for controlling the exciting current of the electromagnet on the basis of a signal from the sensor are provided, and a device including the above elements is provided at least in the upper part of the tower, and is controlled by the exciting current control circuit. A tower vibration control device that suppresses tower vibration by applying the attractive force of an electromagnet to the direction of returning the shake of the tower to a ferromagnetic material.