JPH0143177B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration suppression device for structures on the ground.

Conventionally, this type of device is known as a dynamic damper. However, since dynamic dampers are passive, they can only suppress a single frequency of vibration, so they cannot cope with systems that change over time, and it is extremely difficult to determine their constituent elements. There are many drawbacks.

The present invention aims to provide an active device, in particular, capable of extremely damping the vibration amplitude of a structure due to vibration disturbance from the ground, without the above-mentioned drawbacks of the conventional devices.

For this purpose, the present invention includes a device including an additional weight movably mounted on the floor or ceiling of a structure, and an actuator for driving the additional weight, the stationary part of which is fixed to the floor or ceiling. a control unit that operates the actuator; a vibration detector attached to the structure that detects vibrations of the structure; a vibration detector attached to the ground of the structure that detects vibrations of the ground; The subtraction circuit subtracts the detection signal of the ground vibration detector from the detection signal of the vibration detector and inputs the result to the control section.

FIG. 1 shows an embodiment of the present invention, where 1 is a structure, 1a and 1b are the ceiling and floor of the structure 1, 2 is the ground on which the structure 1 is installed, and 3 is the ceiling of the structure 1. 1a is an additional weight movably mounted; 4 is an electrodynamic actuator that drives the additional weight; 5 is a stationary part of the electrodynamic actuator 4 mounted on the ceiling 1 of the structure 1;
6 is a control circuit for operating the electrodynamic actuator 4; 7 is a vibration detector attached to the structure 1 to detect horizontal vibration acceleration; 8 is a vibration detector attached to the ground 2; A vibration detector 9 detects horizontal vibration acceleration, and is a subtraction circuit that subtracts the detection signal of the vibration detector 8 from the detection signal of the vibration detector 7 and inputs the result to the control circuit 6.

Figure 2 shows additional weight 3 and electrodynamic actuator 4.
4a is a cylindrical excitation magnet,
4b is a center pole, 4c is a yoke, 4d is a moving coil, 4e is a support around which the moving coil 4d is wound, and the support 4e is fixed to the additional weight 3.

FIG. 3 shows a drive system for the additional weight 3 as a block diagram, and 6a is an output circuit of the control circuit 6.

In the above embodiment, when the ground 2 on which the structure 1 is installed vibrates due to an earthquake or the propagation of external vibrations, the structure 1 is excited and vibrates due to the vibration. For convenience of explanation, this vibration is
When is replaced with a one-degree-of-freedom vibration system, the result is shown in Figure 4.
It is a vibration of a system of equivalent mass M and spring stiffness K, and the equation of motion of this mass M is as follows: Z¨ is the horizontal acceleration of the ground, x is the horizontal acceleration of mass M, and x is the vibration amplitude of mass M. Then, M=(x¨+Z¨)+Kx=0 (1). Rewriting this equation (1), we get x¨+ωn ² x=−Z¨ (2), where ωn=√, which represents the natural frequency of this system, and these two equations represent a one-degree-of-freedom vibration system. This is the equation of motion due to acceleration disturbance.

From the above equation (2), in order to reduce the vibration amplitude x of the structure 1, it is effective to apply a vibration suppressing force to the structure 1 as a function of the vibration amplitude x of the structure 1 only. Recognize. The horizontal acceleration Z¨ of the ground 2 is a movement of the ground 2 itself, and is not originally a target of reduction. As is clear from the block diagram of FIG.
This is a servo damping device that aims at suppressing vibrations of a structure 1 by operating an electrodynamic actuator 4 only by a vibration detection signal effective for suppressing vibrations of the structure 1. That is,
As can be seen from Fig. 3, the vibration detector 7 of the structure 1 detects the sum X¨ of the horizontal acceleration x¨ of only the structure 1 and the horizontal acceleration Z¨ of the ground 2, and also detects the vibration of the ground 2. Since the device 8 detects only the horizontal acceleration Z of the ground 2, the subtraction circuit 9 uses the horizontal acceleration x of only the structure 1, which is the difference between them, as an input signal to the control circuit 6, and the control circuit 6 receives this input signal. The current is converted into a velocity amount or a displacement amount of the structure 1, and a current corresponding to the vibration of the structure 1 is supplied from the output circuit 6a to the moving coil 4d of the electrodynamic actuator 4. As a result, a driving force is generated in the movable coil 4d of the electrodynamic actuator 4, and this driving force drives the additional weight 3. At this time, as a reaction, a driving force is also generated in the stationary part of the electrodynamic actuator 4, and this driving force is applied to the ceiling part 1a of the structure 1 via the fixture 5 as a force to counteract the vibration. , Due to this force, the vibration of the structure 1 is damped and suppressed. Since this vibration damping effect is based on the closed-loop servo mechanism as described above, it remains effective even if the vibration system of the structure 1 changes over time.

Note that the present invention is not limited to the above embodiments, and may include placing the additional weight on the floor of the structure, or
It goes without saying that the actuator can be of other types such as hydraulic or pneumatic.

As described above, according to the present invention, a servo mechanism that utilizes the inertial force of an additional weight, and a servo mechanism that responds only to the vibration component of a structure, is used.
The active vibration damping effect provides a device that can effectively and accurately suppress vibrations caused by vibration disturbances from the ground of a structure, regardless of temporal changes in the vibration characteristics.

[Brief explanation of drawings]

FIG. 1 shows one embodiment of the present invention, FIG. 2 shows details of the additional weight and electrodynamic actuator, FIG. 3 shows the drive system of the additional weight as a block diagram, and FIG. The figure shows the equivalent vibration system. 1 is a structure, 1a is a ceiling, 1b is a floor, 2 is a ground, 3 is an additional weight, 4 is an electrodynamic actuator, 5 is a fixture, 6 is a control circuit, 7 and 8 are vibration detectors, 9 is a subtraction circuit.

Claims (1)

[Claims] 1. An additional weight movably placed on the floor or ceiling of a structure, an actuator that drives the additional weight and has a stationary part fixed to the floor or ceiling, and a control unit that operates the actuator. , a vibration detector attached to the structure to detect the structure's vibration, a vibration detector attached to the ground of the structure to detect the ground vibration, and a vibration detector attached to the structure to detect the ground vibration from the detection signals of the structure's vibration detector. A vibration suppression device for a structure comprising a subtraction circuit that subtracts a detection signal from a vibration detector and inputs the result to a control unit.