Vibration isolating structure

Abstract

To provide a vibration isolating structure that enables accurate setting of an inertial mass value by estimating excitation vibration frequency to be controlled.SOLUTION: A vibration isolating structure includes: a structure 2; a floating floor 3 installed above the structure 2; a support spring 4 provided between the structure 2 and the floating floor 3; an inertial mass device 5 provided between the structure 2 and the floating floor 3; and an inertial mass adjustment section 7 that adjusts an inertial mass value of the inertial mass device 5. The inertial mass adjustment section 7 includes: an acceleration measurement section 71 that measures acceleration of the floating floor 3; an excitation vibration frequency estimation section 72 that estimates excitation vibration frequency of the floating floor 3 on the basis of the acceleration measured by the acceleration measurement section 71; an inertial mass value calculation section 73 that calculates the inertial mass value of the inertial mass device 5 required for controlling the excitation vibration frequency estimated by the excitation vibration frequency estimation section 72; and an inertial mass control section 74 that controls the inertial mass device 5 so as to add the inertial mass value calculated by the inertial mass value calculation section 73 to the floating floor 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vibration-isolating structure. [Background technology]

[0002] In live music venues and concert halls, vibrations caused by audience members moving vertically in time with the music can cause surrounding buildings to shake. Vibration-damaging forces generated on the floor can be transmitted to the surrounding area, resulting in vibration problems. One technology to address this vibration problem is a floating floor, isolating the affected area from the structural frame. This type of vibration-damaging structure creates a recess in the structural frame, with a floating floor supported by springs in this recess. The floating floor is supported vertically by springs against the structural frame. Since the frequency at which vertical vibrations cause problems is generally between 2 and 3.5 Hz, floating floors are typically designed with a vertical natural frequency of around 1 Hz and a vertical displacement of no more than 1 to 2 cm during normal use. However, for a typical floating floor with a natural frequency of 1 Hz, a vertical excitation frequency of 2 Hz would transmit more than one-third of the excitation force to the foundation, preventing significant vibration damping. On the other hand, a vibration-proof structure has been proposed in which, by adding an inertial mass device in parallel with a spring member between the floating floor and the structural body, the excitation force transmitted to the foundation at frequencies of 2 to 3.5 Hz, at which vibration damage due to vertical vibration becomes a problem, can be reduced to approximately 1 / 10 or less, thereby achieving a significant vibration-proofing effect (see, for example, Patent Document 1).

[0003] Such vibration-isolating structures can adjust the controlled frequency (cutoff frequency) by setting the inertial mass value, thereby achieving a high vibration reduction effect in the desired frequency range. However, because the inertial mass value is set in advance, it is difficult to change the controlled frequency by changing the inertial mass value after installation. For this reason, for example, if the dominant frequency, such as vertical movement at a concert, changes depending on the melody and the controlled frequency fluctuates, sufficient vibration reduction performance may not be achieved depending on the frequency. In response to this, floating floors have been proposed that allow the inertial mass value to be adjusted and the controlled frequency to be changed and adjusted (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-082541 [Patent Document 2] Japanese Patent Application Publication No. 2019-152288 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is difficult to know the melody and timing of its changes in advance at a concert, etc. Therefore, it is desirable to be able to estimate the excitation frequency to be controlled and set the inertial mass value with high accuracy.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vibration isolation structure that can estimate the excitation frequency to be controlled and set the inertial mass value with high accuracy. [Means for solving the problem]

[0007] In order to achieve the above object, the vibration-proof structure of the present invention comprises a structure, a floating floor installed above the structure, support springs provided between the structure and the floating floor, an inertial mass device provided between the structure and the floating floor, and an inertial mass adjustment unit that adjusts the inertial mass value of the inertial mass device, wherein the inertial mass adjustment unit comprises an acceleration measurement unit that measures the acceleration of the floating floor, an excitation frequency estimation unit that estimates the excitation frequency of the floating floor based on the acceleration measured by the acceleration measurement unit, an inertial mass value calculation unit that calculates the inertial mass value of the inertial mass device required to control the excitation frequency estimated by the excitation frequency estimation unit, and an inertial mass control unit that controls the inertial mass device so as to add the inertial mass value calculated by the inertial mass value calculation unit to the floating floor.

[0008] In the present invention, since the excitation frequency to be controlled can be estimated, the inertial mass value can be set with high accuracy, thereby enabling effective vibration reduction performance to be achieved even when the excitation frequency fluctuates.

[0009] In the vibration-proof structure according to the present invention, the excitation frequency estimation unit may calculate a Fourier spectrum based on acceleration data for a certain section measured by the acceleration measurement unit, set a threshold value for the maximum amplitude of the calculated Fourier spectrum, determine whether the maximum amplitude of the Fourier spectrum is equal to or greater than the threshold value, and, if the maximum amplitude of the Fourier spectrum is equal to or greater than the threshold value, calculate a predominant frequency to estimate the excitation frequency.

[0010] By setting a threshold for the maximum amplitude value of the Fourier spectrum calculated based on the measured acceleration of the floating floor and estimating the dominant frequency, for example, at a concert or live performance, if the maximum amplitude value of the Fourier spectrum is above the threshold, it can be determined that a song is in progress (being played), and if it is below the threshold, it can be determined that the song is not being played.This makes it possible to accurately estimate the frequency to be controlled within the frequency range to be adjusted by the inertial mass device. [Effects of the Invention]

[0011] According to the present invention, the excitation frequency to be controlled can be estimated and the inertial mass value can be set with high accuracy. [Brief explanation of the drawings]

[0012] [Figure 1] 1A and 1B are diagrams illustrating an anti-vibration structure according to an embodiment of the present invention. [Figure 2] 10 is a flowchart of calculation of an inertial mass value. [Figure 3] 10 is a graph showing the time history of the acceleration of the floating floor and the maximum amplitude of the spectrum. [Figure 4] 10 is a graph showing threshold settings for amplitude. [Figure 5] 10 is a graph showing an estimation of excitation frequency and BPM. [Figure 6](a) is a graph showing the Fourier spectrum and excitation frequency in a song with BPM=100, and (b) is a graph showing the Fourier spectrum and excitation frequency in a song with BPM=140. [Figure 7] 10 shows an example of the estimation result of the excitation frequency when the melody fluctuates. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, vibration-isolating structures according to embodiments of the present invention will be described with reference to FIGS. 1, the vibration-proof structure 1 according to this embodiment includes a structure 2, a floating floor 3 installed above the structure 2, a support spring 4 provided between the structure 2 and the floating floor 3, an inertial mass device 5 provided between the structure 2 and the floating floor 3, a damping mechanism 6 provided between the structure 2 and the floating floor 3, and an inertial mass adjustment unit 7 that adjusts the inertial mass of the inertial mass device 5. The support spring 4, the inertial mass device 5, and the damping mechanism 6 are provided in parallel between the structure 2 and the floating floor 3.

[0014] The vibration-isolation structure 1 according to this embodiment is intended to be used in buildings such as large halls, with people and objects standing on the floating floor 3. When the building is used for live music concerts, dance performances, etc., the vibration-isolation structure 1 is configured so that vertical vibrations (so-called vertical vibrations) occur in the floating floor 3 when a large number of people on top of the floating floor 3 bend and stretch to the music, causing the floating floor 3 to vibrate. In this embodiment, a concert is held on the floating floor 3, and the movements of the audience change depending on the melody of the music being played, causing the vibrations of the floating floor 3 to change. Note that when the building is used for exhibitions, sporting events, etc., the floating floor 3 may be configured to be used as a fixed floor that does not vibrate vertically.

[0015] The structure 2 is, for example, a building foundation and is constructed of reinforced concrete. The floating floor 3 is formed in the shape of a flat plate and is installed above the structure 2 with the plate surface oriented horizontally. A plurality of support springs 4 are provided horizontally spaced apart between the structure 2 and the floating floor 3. When the floating floor 3 is vibrated, the support springs 4 expand and contract, causing the floating floor 3 to vibrate vertically relative to the structure 2. The spring stiffness of the plurality of support springs 4 is set to the same value. The damping mechanism 6 is, for example, a viscous damper. The inertial mass device 5 is installed between the structure 2 and the floating floor 3. The inertial mass device 5 is, for example, a rotary inertial mass damper.

[0016] The inertial mass adjustment unit 7 has an acceleration measurement unit 71 , an excitation vibration frequency estimation unit 72 , an inertial mass value calculation unit 73 , and an inertial mass control unit 74 . The acceleration measurement unit 71 is an accelerometer or the like attached to the floating floor 3. The acceleration measurement unit 71 measures vibrations such as the acceleration of the floating floor 3. The excitation frequency estimation unit 72 calculates the amplitude and dominant frequency of the vibration of the floating floor 3 based on the measurement data of the acceleration measurement unit 71, and estimates the excitation frequency to be controlled. The excitation frequency estimation unit 72 estimates the melody (excitation frequency) from the vibration of the floating floor 3 and determines the need for control.

[0017] The inertial mass value calculation unit 73 calculates the inertial mass value of the inertial mass unit 5 required to control the excitation frequency estimated by the excitation frequency estimation unit 72. The excitation frequency (frequency to be controlled) is a natural frequency consisting of the spring stiffness of the support springs 4 of the floating floor 3 and the inertial mass of the inertial mass unit 5. If the frequency to be controlled is f and the spring stiffness is k, then the required inertial mass m d (Inertia mass value) can be calculated using the following formula (1). m d =k / (2πf) 2 ···(1) The inertial mass control unit 74 controls the inertial mass device 5 so that the inertial mass value becomes the inertial mass value calculated by the inertial mass value calculation unit 73. In other words, the inertial mass control unit 74 controls the inertial mass device 5 so that the inertial mass value calculated by the inertial mass value calculation unit 73 is added to the floating floor 3.

[0018] A flowchart for calculating the inertial mass value is shown in Figure 2. In order to automatically estimate the excitation frequency in real time, measurement data from the acceleration measurement unit 71 at regular intervals (for example, every 10 seconds) up to a certain period in the past (for example, 1 minute) is used. First, the acceleration of the floating floor 3 is measured by the acceleration measuring unit 71 (S-1). Measurement data for a certain section measured by the acceleration measuring unit 71 is extracted (S-2), and a Fourier spectrum (frequency response) is calculated based on the extracted measurement data (S-3). Next, a threshold is set for the calculated maximum amplitude of the Fourier spectrum, and it is determined whether the maximum amplitude of the Fourier spectrum is equal to or greater than the threshold (S-4). If the maximum amplitude of the Fourier spectrum is less than the threshold (NO), no control is performed, and the process returns to step S-1, where the acceleration measurement unit 71 measures the acceleration of the floating floor 3. If the maximum amplitude of the Fourier spectrum is equal to or greater than the threshold (YES), control is performed according to the melody of the song (S-5 to S-7). By setting a threshold, if the maximum amplitude of the Fourier spectrum is equal to or greater than the threshold, it is determined that a song is not in progress. If the maximum amplitude of the Fourier spectrum is less than the threshold, it is determined that a song is not in progress (for example, before or after a song, during an MC, during a break, before the doors open, after the performance ends, etc.), and no control is performed, and the nominal inertial mass value (initial setting value) is maintained.

[0019] If it is determined that the maximum amplitude of the Fourier spectrum is equal to or greater than the threshold, the dominant frequency is calculated (S-5). Based on the calculated Fourier spectrum, the dominant frequency is extracted within the range of 2.0 to 4.0 Hz, which is the frequency range to be controlled, and the excitation frequency of the control target (control target frequency) is estimated by the excitation frequency estimation unit 72 (S-6). The inertial mass value is calculated from the estimated excitation frequency (S-7). For example, depending on the melody, such as a song with a BPM (Beats Per Minute) of 120 or less, the dominant frequency may be outside the range of 2.0 to 4.0 Hz. However, by using the nth harmonic component as the frequency to be controlled, the excitation frequency can be estimated within the control range of the inertial mass device 5.

[0020] Figures 3 to 5 show examples of processing results using measurement data of the floating floor during an actual live performance. As shown in Figures 3 to 5, the amplitude of the Fourier spectrum is calculated based on the acceleration of the floating floor 3 measured by the acceleration measurement unit 71, and when the threshold value is exceeded, the dominant frequency is calculated, making it possible to accurately estimate the excitation frequency of the floating floor 3. Furthermore, as shown around 500 seconds to 1500 seconds in the time history waveform, it is possible to detect fluctuations in the excitation frequency due to changes in songs even when consecutive songs are played.

[0021] Figure 6 shows the Fourier spectrum and excitation frequency (controlled frequency) during songs with BPM=110 and BPM=140. As shown in Figure 6(a), when BPM=110, the dominant frequency of the floating floor is around 1.8 Hz, but by setting the second harmonic component, around 3.6 Hz, as the controlled frequency, the excitation frequency is estimated in the range of 2.0 to 4.0 Hz, which is the control range of the inertial mass device. Also, as shown in Figure 6(b), when BPM=140, the dominant frequency of the floating floor is around 2.3 Hz, which is within the range of 2.0 to 4.0 Hz, so the dominant frequency is estimated as the excitation frequency.

[0022] In this embodiment, it is possible to detect changes in the excitation frequency even when the melody changes during a song. In this embodiment, the excitation frequency is estimated automatically in real time, so it is possible to detect fluctuations in the excitation frequency that accompany changes in the melody (changes in BPM) during a song, as well as changes in the song. Figure 7 shows an example of the estimation result of the excitation frequency when the melody changes.

[0023] Next, the operation and effect of the vibration isolation structure according to this embodiment will be described. The vibration-isolating structure according to this embodiment can accurately estimate the excitation frequency to be controlled automatically in real time, allowing the inertial mass value to be set with high accuracy, thereby enabling the structure to effectively demonstrate vibration reduction performance even when the excitation frequency fluctuates.

[0024] By setting a threshold value for the maximum amplitude value of the Fourier spectrum calculated based on the measured acceleration of the floating floor 3 and estimating the dominant frequency, it is possible to determine whether a song is in progress and accurately estimate the frequency to be controlled within the frequency range to be adjusted by the inertial mass device 5.

[0025] When estimating the excitation frequency of 2 to 3 Hz based on the calculated Fourier spectrum, by extracting the dominant frequency within the range of 2.0 to 4.0 Hz, which is the target frequency for vertical bending, and setting it as the frequency to be controlled, it is possible to accurately estimate the excitation frequency within the control range of the inertial mass unit 5. For example, when BPM = 110, the dominant frequency of the floating floor 3 is around 1.8 Hz, but by setting the second harmonic component, around 3.6 Hz, as the frequency to be controlled, it is possible to stably estimate the excitation frequency within the range of 2.0 to 4.0 Hz, which is the control range of the inertial mass unit 5.

[0026] Since the excitation frequency is estimated in real time, it is possible to detect fluctuations in the excitation frequency when multiple songs are played in succession or when the melody (BPM) changes within a song, and adjust the characteristics of the floating floor 3. Even if there is a problem with estimating the excitation frequency, the vibration reduction rate will be low if no control is performed, but due to the effect of the inertial mass value set as the initial value (for example, 2.5 Hz as the cut-off frequency), a certain vibration reduction effect can be obtained, with the reaction force magnification being roughly 1 / 10 or less at 2 to 4 Hz.

[0027] Although the embodiment of the vibration-proof structure according to the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate within the scope of the invention. For example, in the vibration-proof structure 1 of the above embodiment, the damping mechanism 6 is provided between the structure 2 and the floating floor 3, but this does not necessarily have to be provided.

[0028] The Sustainable Development Goals (SDGs) are 17 international goals adopted at the United Nations Summit in September 2015. The vibration-proof structure of this embodiment can contribute to achieving one of the 17 SDGs, such as goal 9, "Create indispensable infrastructure for industry, innovation and sustainable development." [Explanation of symbols]

[0029] 1. Vibration-proof structure 2 structure 3. Floating floor 4 Support spring 5 Inertial mass device 6 Damping mechanism 7 Inertial mass adjustment section 71 Acceleration measurement unit 72 Excitation frequency estimation unit 73 Inertia mass value calculation unit 74 Inertial mass control unit

Claims

1. a structure; a floating floor installed above the structure; A support spring provided between the structure and the floating floor; an inertial mass device provided between the structure and the floating floor; an inertial mass adjustment unit that adjusts the inertial mass value of the inertial mass device, The inertial mass adjustment unit is an acceleration measuring unit that measures the acceleration of the floating floor; an excitation frequency estimation unit that estimates the excitation frequency of the floating floor based on the acceleration measured by the acceleration measurement unit; an inertial mass value calculation unit that calculates an inertial mass value of the inertial mass unit required to control the excitation frequency estimated by the excitation frequency estimation unit; an inertial mass control unit that controls the inertial mass device so as to add the inertial mass value calculated by the inertial mass value calculation unit to the floating floor.

2. The excitation frequency estimation unit calculating a Fourier spectrum based on acceleration data for a certain section measured by the acceleration measuring unit; A threshold is set for the maximum amplitude of the calculated Fourier spectrum, and it is determined whether the maximum amplitude of the Fourier spectrum is equal to or greater than the threshold; 2. The vibration isolation structure according to claim 1, wherein when the maximum amplitude of the Fourier spectrum is equal to or greater than a threshold value, the dominant frequency is calculated to estimate the excitation frequency.

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