JP2010085373A - Device, method, and program for detecting frequency of vibrations and antivibration apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the amount of time required to detect the frequency of vibrations of an object of detection after a change in the frequency of vibrations. <P>SOLUTION: Vibration detection data input from a vibration sensor that detects vibrations of a structure whose vibration is to be suppressed are acquired in a cycle T<SB>0</SB>(206). A vibrational component in the range of frequency of vibrations of a vibration-free object is extracted (208). After that, the integral value B of the vibrational component A thus extracted is computed (210). The effective value Ae of the vibrational component A is computed (212), and the effective value Be of the integral value B is computed (214). The angular frequency ω of vibrations of the vibration-free object is computed by dividing the effective value Ae by the effective value Be (216). The center frequency ω<SB>0</SB>of vibrations of the vibration-free object is computed by eliminating a noise component by performing low-pass filtering on the angular frequency ω of vibrations N times (218). Thus, the frequency of vibrations of the vibration-free object can be detected in a small amount of time even after a change in the frequency of vibrations. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a frequency detection device, a method, a program, and a vibration control device, and in particular, a frequency detection device that detects a frequency of an input signal that exhibits a sine wave or a periodic change approximated to a sine wave, and the frequency detection device. The present invention relates to a vibration detection device provided with a frequency detection method, a frequency detection method applicable to the frequency detection device, and a frequency detection program for causing a computer to function as the frequency detection device.

Conventionally, the vibration target object is detected by detecting the vibration of the vibration target object and controlling the excitation force applied to the vibration target object by the vibration control actuator according to the vibration detection result of the vibration target object. There is known a vibration damping device that suppresses vibrations of the above (for example, see Patent Documents 1 and 2). A zero crossing method is used to detect the frequency in this type of vibration control device. The zero-crossing method measures the time interval at the point where the detection target signal indicating a period change crosses the zero line several times, and doubles the measured time interval to obtain the period T, thereby detecting the detection target signal. The frequency (frequency) f (= 1 / T) of the period change is detected. The zero crossing method is frequently used not only for obtaining the vibration frequency of an object but also for detecting the vibration frequency in various fields.
JP-A-5-2448489 JP 2002-115742 A

  In the frequency detection by the zero crossing method, in practice, an average time interval of the timing of crossing the zero line is often obtained from the number of times the zero line is crossed over a certain time length. At this time, if the frequency of the detection target changes by ΔF, theoretically, it takes a time of 1 / Δf seconds at the minimum to detect the changed frequency, and the frequency of the detection target falls in the low frequency range. Accordingly, there is a problem that the above time becomes longer. For example, if the detection target frequency changes from 3.0 Hz to 3.1 Hz by 0.1 Hz, detection of the frequency after the change requires at least 10 seconds (= 1 / | 3.0-3.1 |). Become. In addition, when noise components are mixed in the signal used to detect the frequency, filter processing is also required to remove the mixed noise components. The time required for detecting the frequency after the change is longer than the above theoretical value.

  In the detection of the frequency by the zero crossing method, in order to confirm how much time is actually required to detect the frequency after the change when the frequency of the detection target is changed, the inventors of the present application perform a filtering process. The noise component of the input signal is removed and the frequency of the input signal is changed from the state in which the input signal having a frequency of 30 Hz is input to the existing frequency detection device configured to detect the frequency by the zero crossing method. An experiment was conducted to measure the time required until a change in frequency was detected when switching to 40 Hz. As a result, it has become clear that it takes about 4 seconds until the frequency detection result becomes 40 Hz after the frequency of the input signal is switched to 40 Hz. From this result, when the frequency of the detection target is changed by detecting the frequency in the lower frequency range, for example, when the frequency of the detection target is changed from 3.0 Hz to 4.0 Hz, the value of 1 / Δf is Since it is 10 times the above experiment, it can be estimated that the detection of the frequency after the change is likely to take a very long time of about 40 seconds.

  Therefore, when the detection of the frequency by the zero crossing method is applied to, for example, vibration suppression of a vibration control object that vibrates at a relatively low frequency, the vibration control There has been a problem that it is difficult to accurately control the vibration of the object to be controlled because a very long time delay occurs in the control of the actuator. In addition to the zero crossing method described above, a method of counting the number of beats due to wave interference between the vibration to be detected and the reference vibration (heterodyne method) is also known as the frequency detection method. Also in the heterodyne method, the beat time interval increases as the two frequencies approach each other. Therefore, as with the zero crossing method, it takes time to detect the changed frequency when the frequency changes. there were.

  The present invention has been made in consideration of the above facts, and when the frequency of the detection target changes, the frequency detection device, the frequency detection method, and the vibration that can reduce the time required to detect the frequency after the change The purpose is to obtain a number detection program.

  It is another object of the present invention to provide a vibration damping device that can accurately suppress vibration of a vibration suppression target object even when the vibration frequency of the vibration suppression target object changes.

When a certain periodic function f (t) = Asin (ωt + θ) (where ω = 2πf, f is the frequency of the periodic function f (t), A is the amplitude, and θ is the phase) is integrated over time t, the periodic function F ( t) =-(A / ω) cos (ωt + θ) is obtained. Thus, the periodic function F (t) obtained by integrating the periodic function f (t) at time t has an amplitude that is 1 / ω times the original periodic function f (t). The effective value fe (t) of the periodic function f (t) and the effective value Fe (t) of the periodic function F (t) are expressed by the following equation (1).
fe (t) = A / √2 Fe (t) = A / (√2 · ω) (1)
Thus, since the effective value Fe (t) of the periodic function F (t) is also 1 / ω times the effective value fe (t) of the periodic function f (t), the following equation (2) is obtained. By dividing the ratio of the effective value fe (t) to the effective value Fe (t) (the value obtained by dividing the effective value fe (t) by the effective value Fe (t)) by 2π, the periodic function f (t) The frequency f is obtained.
fe (t) / (Fe (t) · 2π) = ω / 2π = 2πf / 2π = f (2)
Further, when the periodic function f (t) = Asin (ωt + θ) is differentiated with respect to time t, the periodic function F ′ (t) = Aωcos (ωt + θ) is obtained. Thus, the periodic function F ′ (t) obtained by differentiating the periodic function f (t) with respect to time t has an amplitude that is ω times the original periodic function f (t). The effective value fe (t) of the periodic function f (t) and the effective value F′e (t) of the periodic function F ′ (t) are expressed by the following equation (3).
fe (t) = A / √2 Fe (t) = (A · ω) / √2 (3)
Thus, since the effective value F′e (t) of the periodic function F ′ (t) is also ω times the effective value fe (t) of the periodic function f (t), the following equation (4) is obtained. Further, by dividing the ratio of the effective value fe (t) to the effective value Fe (t) (the value obtained by dividing the effective value F′e (t) by the effective value fe (t)) by 2π, the periodic function f The frequency f of (t) is obtained.
F′e (t) / (fe (t) · 2π) = ω / 2π = 2πf / 2π = f (4)
As is clear from the above equations (2) and (4), the inventors of the present application determine that the ratio between the effective value of the input signal and the effective value of the integral value or the differential value of the input signal is the change in the period of the input signal. If the frequency f is calculated based on the fact that it is proportional to the frequency f, the frequency to be detected is also changed after the change compared to the case of using the zero crossing method or the like. The inventors have conceived that the vibration frequency can be detected in a short time, and have achieved the present invention.

  Based on the above, the frequency detection device according to the first aspect of the present invention includes a first calculation means for repeatedly calculating an integral value or a differential value of an input signal indicating a sine wave or a periodic change approximated to a sine wave, and the input signal. Second effective means for repeatedly calculating the effective value of the integral value or the differential value calculated by the first calculating means, and the effective value of the input signal calculated by the second calculating means, And third calculation means for repeatedly calculating the frequency of the periodic change of the input signal using a ratio of the integral value or the effective value of the differential value calculated by the second calculation means. It is configured.

  According to the first aspect of the present invention, the integral value or the differential value of the input signal indicating a sine wave or a periodic change approximated to a sine wave is repeatedly calculated by the first calculation means, and the effective value of the input signal and the first calculation means The effective value of the integral value or differential value of the input signal calculated by the above is repeatedly calculated by the second calculation means. The third calculating means uses the ratio between the effective value of the input signal calculated by the second calculating means and the effective value of the integral value or differential value of the input signal calculated by the second calculating means. Repeat the calculation of the frequency of the period change.

  When measuring the frequency by measuring the period of the input signal, such as the zero crossing method, the frequency at which the detection result of the frequency is updated depends on the frequency of the target frequency, and the detection of the frequency is detected. Even if it is performed with a period that is much shorter than the period of the target frequency, the period in which the detection result of the frequency is updated is theoretically at least 1/2 of the period of the target frequency. On the other hand, the invention according to claim 1 repeats the calculation (detection) of the frequency using the ratio of the effective value of the input signal and the effective value of the integral value or differential value of the input signal. Yes, the effective value of the input signal and the effective value of the integral value or the differential value of the input signal change immediately according to the change of the frequency when the frequency of the periodic change of the input signal changes. Therefore, the cycle of the input signal is measured as in the zero crossing method, etc. by making the calculation cycle of the repetitive calculation of the first calculation means to the third calculation means sufficiently smaller than the frequency of the frequency to be detected. Compared with the case where the frequency is detected, the time required to detect the frequency after the change can be shortened when the frequency of the detection target (the frequency of the change in the period of the input signal) changes.

  In the first aspect of the invention, when the first calculation means calculates the integral value of the input signal, for example, as described in claim 2, the second calculation means sets the effective value of the integral value of the input signal. The third calculating means vibrates the effective value of the input signal calculated by the second calculating means and the value obtained by dividing the effective value of the integral value of the input signal calculated by the second calculating means and 2π, respectively. It can be configured to operate as a number. By the above calculation, the frequency f of the period change of the input signal can be calculated (detected) as is clear from the above equation (2).

  In the first aspect of the invention, when the first calculation means calculates the differential value of the input signal, for example, as described in claim 3, the second calculation means sets the effective value of the differential value of the input signal. The third calculating means vibrates the effective value of the differential value of the input signal calculated by the second calculating means and the value obtained by dividing the effective value of the input signal calculated by the second calculating means and 2π respectively. It can be configured to operate as a number. By the above calculation, the frequency f of the period change of the input signal can be calculated (detected) as is clear from the above equation (4).

  In the invention according to any one of claims 1 to 3, the effective value of the effective value of the input signal, the effective value of the integral value of the input signal, or the effective value of the differential value of the input signal by the second calculating means. For example, as described in claim 4, the value is calculated by calculating a square value with respect to an input signal to be calculated as an effective value, an integral value of the input signal, or a differential value of the input signal, and a predetermined frequency or more. This can be done by performing a low-pass filter process for removing signal components in the frequency range of and calculating a ½ power value.

  Moreover, in the invention according to any one of claims 1 to 4, the first calculation means may be configured such that, for example, as described in claim 5, the integrated value of the input signal or the differential value of the input signal with respect to the input signal. Before performing this calculation, it is preferable to perform a band-pass filter process for removing signal components that are out of a predetermined frequency range including the frequency to be detected from the input signal. As a result, even when a noise component that indicates a periodic change and the frequency of the periodic change is outside the predetermined frequency range is mixed in the input signal, the mixed noise component is removed by the band-pass filter processing. Thus, the influence of the mixed noise component on the frequency detection can be reduced, and the frequency detection accuracy can be improved.

  In addition, as a result of experiments conducted by the inventors of the present application, when the frequency of the change in period of the input signal is detected by applying the present invention, a noise component in a relatively high frequency range is superimposed on the detection result of the frequency, It was confirmed that the value of the detected frequency fluctuates in a relatively short cycle due to the influence of this superimposed noise component (details will be described later). In consideration of this, in the invention according to any one of claims 1 to 5, the third calculation means, for example, as described in claim 6, from the calculation result of the frequency, from the frequency of the detection target It is preferable that the low-pass filter process for removing signal components in a frequency range higher than a predetermined frequency is performed N times (N ≧ 1). Thereby, it is possible to remove a superimposed noise component in a relatively high frequency range from the calculation result of the frequency, and it is possible to improve the frequency detection accuracy.

  According to a seventh aspect of the present invention, there is provided a vibration damping device comprising: detection means for detecting vibration of a vibration suppression target object having a spring and a damper interposed between the reference object and a vibration detection signal output from the detection means. The frequency detection device according to any one of claims 1 to 6, which detects the vibration frequency of the vibration suppression target object as the input signal, and the excitation force that suppresses the vibration of the vibration suppression target object. Based on the vibration frequency of the vibration of the vibration target object detected by the vibration frequency detection device and the vibration suppression actuator. And a control means for controlling the excitation force applied to the target object.

  A seventh aspect of the invention includes the vibration detection device according to any one of the first to sixth aspects, wherein the vibration of the vibration suppression target object in which a spring and a damper are interposed between the reference object and the reference object. Is detected by the detection means, and the above-described frequency detection device detects the vibration frequency of the vibration control target object using the vibration detection signal output from the detection means as an input signal. Thereby, even when the vibration frequency of the vibration suppression target object changes, the changed frequency is detected in a short time by the frequency detection device. The control means controls the excitation force applied to the vibration suppression object by the vibration suppression actuator based on the vibration frequency in the vibration of the vibration suppression object detected by the vibration frequency detection device. The control delay when the vibration frequency changes can be suppressed to the minimum, and the vibration of the vibration control target object can be accurately suppressed even when the vibration frequency of the vibration control target object changes.

  According to an eighth aspect of the present invention, there is provided a frequency detection method, comprising: calculating an integral value or a differential value of an input signal indicating a sine wave or a periodic change approximated to a sine wave; and calculating an effective value of the input signal and the input signal. The effective value of the integral value or the differential value of the input signal is calculated, and the period change of the input signal is calculated using the ratio between the effective value of the input signal and the effective value of the integral value or the differential value of the input signal. Since the calculation of the frequency is repeated, the time required for detecting the frequency after the change can be reduced when the frequency of the detection target is changed, as in the first aspect of the invention.

  According to a ninth aspect of the present invention, there is provided a frequency detection program comprising: a first calculation means for calculating an integral value or differential value of an input signal indicating a sine wave or a periodic change approximated to a sine wave; A second computing means for computing an effective value of the integral value or the differential value computed by the first computing means, and an effective value of the input signal computed by the second computing means; 2 function as third calculation means for calculating the frequency of the periodic change of the input signal using the ratio of the integral value or the effective value of the differential value calculated by the calculation means.

  Since the frequency detection program according to the invention described in claim 9 is a program for causing a computer to function as the first calculation means, the second calculation means, and the third calculation means, the computer according to claim 9. By executing the frequency detection program according to the invention, the computer functions as the frequency detection device according to claim 1, and the frequency of the detection target is changed, as in the invention according to claim 1. In this case, the time required for detecting the frequency after the change can be shortened.

  As described above, the present invention calculates the integral value or differential value of the input signal, calculates the effective value of the input signal, and the effective value of the integral value or differential value of the input signal, Because the frequency of the input signal's period change is calculated using the ratio of the input signal's integral value or differential value to the effective value, detection of the changed frequency when the target frequency changes It has an excellent effect that the time required for the process can be shortened.

  According to the present invention, the vibration frequency detection device according to any one of claims 1 to 6 detects the vibration frequency of the vibration target object, and based on the detected frequency, the vibration damping actuator Since the excitation force applied to the vibration suppression target object is controlled, there is an excellent effect that the vibration of the vibration suppression target object can be accurately suppressed even when the vibration frequency of the vibration suppression target object changes.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a structure (building) 10 according to the present embodiment. In the structure 10, a pile 12 made of concrete or the like is formed in a vertical direction with respect to the ground 22, and a plurality of pillars 14 made of H steel and a plurality of beams 16 are assembled and fixed on the pile 12 so that the ground 20 Built on top. The structure 10 has a hall 24 on the top floor that can accommodate a large number of people. The hole 24 is provided with a vibration sensor 26 that detects vibration (amplitude and vibration frequency) of the upper structure including the hole 24 generated on the floor 18 of the hole 24.

  On the other hand, in the central portion 14B of the plurality of pillars 14A immediately below the hole 24, vibration (see arrow B in FIG. 1) that cancels the vibration of the upper structure (see arrow A in FIG. 1) generated on the floor 18 of the hole 24. A vibration damping device 100 capable of generating the above is attached. On the lower floor of the hall 24, a control device 30 that controls vibration generated by the vibration control device 100 based on the amplitude and frequency of vibration detected by the vibration sensor 26 is installed. The control device 30 and the vibration sensor 26 are connected by a cable 28. More specifically, as shown in FIG. 4, the control device 30 and the vibration sensor 26 are connected to a computer 88 via an amplifier 84 and an A / D converter 86 of the control device 30. . Therefore, the vibration detection signal output from the vibration sensor 26 is amplified by the amplifier 84, converted into digital vibration detection data by the A / D converter 86, and then input to the computer 88. The control device 30 and the vibration control device 100 are connected by a cable 32. The control device 30 has a built-in power supply (not shown), and electric power for operating the vibration control device 100 is supplied from the control device 30 to the vibration control device 100 via the cable 32.

  In addition, in the structure 10 according to the present embodiment, a portion (lower structure) below the portion where the vibration damping device 100 is attached and a portion above the portion where the vibration damping device 100 is attached. Support members such as columns and beams are provided in addition to the vibration damping device 100 between the (the upper structure including the hole 24), and these support members are connected to the lower structure and the upper structure. The above support member can be represented by a spring and a damper when modeled with respect to the transmission of vibration between them. Accordingly, in the structure 10 according to the present embodiment, the lower structure is the reference object according to claim 7, the upper structure is the vibration suppression target object according to claim 7, and the support member is the claim. 7 corresponding to “springs and dampers interposed between the reference object and the vibration suppression target object”. The vibration control device 100 corresponds to the vibration control actuator described in claim 7, and the vibration sensor 26 corresponds to the detection means described in claim 7.

  As shown in FIG. 2A, the vibration damping device 100 is made of a steel plate and is horizontally disposed between the flanges of the central portion 14B of the column 14A and welded to the flanges of the central portion 14B. 106, and storage portions 107A and 107B surrounded by the ceiling wall 104 and the bottom wall 106 are respectively formed on both sides of the web of the central portion 14B. The vibration control devices 100 are respectively provided in the storage portions 107A and 107B. Contained. In addition, since the damping device 100 accommodated in storage part 107A, 107B is the same structure, below, the damping device 100 accommodated in storage part 107A is demonstrated.

  As shown in FIGS. 2A and 2B, the vibration damping device 100 includes a vibration generating unit 108 that generates vibrations, and a ceiling wall 104 and a bottom wall by amplifying the frequency generated by the vibration generating unit 108. It is roughly divided into a vibration amplifying unit 110 that transmits to 106.

  The vibration unit 108 includes a column 120 in which a pair of channel steels 140 are erected on the bottom plate 118 so that each opening of a U-shaped cross section is opposed to each other while forming a gap 121. Two auxiliary columns 126 standing on both sides, a movable portion 122 provided in a hollow cylindrical shape so as to surround the column 120, and a top plate 116 supported by the column 120 and the auxiliary columns 126 are provided. . A weight 124 made of a steel plate is fixed to the outer surface of the movable portion 122 in a replaceable manner by fixing means such as bolts and nuts (not shown). The weight of the entire movable portion 122 can be changed by changing the weight of the weight 124 fixed to the outer surface of the movable portion 122.

  A plurality of permanent magnets 142 are arranged along the vertical direction on the inner side (web) of the channel steel 140 constituting the support column 120. In addition, an electromagnetic coil 130 wound around a core metal (not shown) is disposed in the support column 120 (in a hollow portion formed by the opening of the pair of channel steels 140). It is connected to the movable part 122 through a support member 128 extending therethrough. Therefore, the electromagnetic coil 130, the movable portion 122, and the weight 124 are integrally movable along the support column 120 in the vertical direction. Further, the distance between the electromagnetic coil 130 and the permanent magnet 142 is maintained approximately constant regardless of the position in the vertical direction. The electromagnetic coil 130, the movable part 122, and the weight 124 correspond to the auxiliary mass part described in claim 3, and these are referred to as “auxiliary mass part” as necessary.

  Each of the electromagnetic coils 130 is connected to the control device 30 via a cable 132. Specifically, as shown in FIG. 4, the electromagnetic coil 130 is connected to a computer 88 via an electromagnetic coil drive circuit 90 of the control device 30. The electromagnetic coil drive circuit 90 supplies a drive current to the electromagnetic coil 130, and the computer 88 functions as an electromagnetic actuator in which the electromagnetic coil 130 and the plurality of permanent magnets 142 function as an auxiliary mass including the electromagnetic coil 130, the movable portion 122, and the weight 124. Part moves in the vertical direction (in the direction of arrow F in FIG. 2 (B)) with a period and amplitude according to the vibration component in the vibration frequency range of the vibration isolation object among the vibrations detected by the vibration sensor 26. The direction and magnitude of the drive current supplied to the electromagnetic coil 130 by the electromagnetic coil drive circuit 90 is controlled. Due to the vertical movement (displacement) of the auxiliary mass part composed of the electromagnetic coil 130, the movable part 122, and the weight 124, the vibration excitation part 108 generates an excitation force (vibration for canceling the vibration component to be isolated). Vibration force).

  On the other hand, the vibration amplifying unit 110 includes a coil spring 112 having a predetermined spring constant (inherent rigidity) and a variable rigidity spring 40 capable of changing the spring constant (rigidity) from the outside. The coil spring 112 and the variable stiffness spring 40 are respectively provided between the ceiling wall 104 and the top plate 116 and between the bottom wall 106 and the bottom plate 118, and each coil spring 112 and variable stiffness spring 40 has one end on the ceiling. The other end is fixed to the top plate 116 or the bottom plate 118. Hereinafter, the configuration of the variable rigid spring 40 provided between the ceiling wall 104 and the top plate 116 will be described as an example, but the variable rigid spring 40 provided between the bottom wall 106 and the bottom plate 118 is also configured in the same manner. It is.

  As shown in FIG. 3 (A), the variable rigid spring 40 is configured by connecting three variable spring units 42, 44, 46 having a displacement lock function in series along the vertical direction. The variable spring unit 42 includes a substantially flat lower attachment member 54 and a substantially flat upper attachment member 52 disposed above the lower attachment member 54 with a space therebetween. A metal coil spring 50 is disposed between the lower mounting member 54 and the upper mounting member 52. The coil spring 50 is fixed to the upper mounting member 52 at the upper end and to the lower mounting member 54 at the lower end by bonding or the like. Has been. Therefore, in the variable spring unit 42, the state in which the space between the upper mounting member 52 and the lower mounting member 54 is maintained by the coil spring 50 and the variable spring unit 42 is displaced in the vertical direction (the upper mounting member and When an external force (which changes the distance to the lower mounting member) is applied, the coil spring 50 expands and contracts to cause a displacement that is inversely proportional to the spring constant of the coil spring 50 (a displacement that changes the distance).

  Similarly, the variable spring unit 44 includes a lower mounting member 66, an upper mounting member 64, and a metal coil spring 62. When an external force that displaces the variable spring unit 44 in the vertical direction is applied, the coil spring 62 expands and contracts. Thus, a displacement that is inversely proportional to the spring constant of the coil spring 62 (a displacement in which the interval between the upper mounting member and the lower mounting member changes) is generated. The variable spring unit 46 includes a lower mounting member 76 and an upper mounting member 74. And a metal coil spring 72, and when an external force is applied to displace the variable spring unit 46 in the vertical direction, the coil spring 72 expands and contracts to cause a displacement that is inversely proportional to the spring constant of the coil spring 72 (upper mounting member and lower mounting). (Displacement in which the distance from the member changes) occurs. The coil springs 50, 62, and 72 of the variable spring units 42, 44, and 46 may have the same spring constant, but preferably have different spring constants.

  The lower mounting member 54 of the variable spring unit 42 is formed with a protruding portion 54A that protrudes downward from substantially the center of the lower surface. The upper mounting member 64 of the variable spring unit 44 has a protruding portion 54A that is approximately centered on the upper surface. A hole 64 </ b> A having an inner diameter substantially equal to the outer diameter is formed. The protruding portion 54A is fitted in the hole 64A, thereby preventing the relative movement of the variable spring units 42 and 44 in the left-right direction. Similarly, the lower mounting member 66 of the variable spring unit 44 is formed with a protruding portion 66A that protrudes downward from substantially the center of the lower surface, and the upper mounting member 74 of the variable spring unit 46 protrudes at the approximately center of the upper surface. A hole 74A having an inner diameter substantially equal to the outer diameter of 66A is formed. The protrusion 66A is fitted in the hole 74A, thereby preventing the relative movement of the variable spring units 44 and 46 in the left-right direction. The upper attachment member 52 of the variable spring unit 42 is attached to the ceiling wall 104 by fixing means such as adhesion or fastening of bolts, nuts, etc., and the upper attachment member 54 of the variable spring unit 42 and the upper part of the variable spring unit 44 are fixed. The attachment member 64, the lower attachment member 66 of the variable spring unit 44 and the upper attachment member 74 of the variable spring unit 46, and the lower attachment member 76 and the top plate 116 of the variable spring unit 44 are also fixed by the same fixing means. ing.

  On the upper surface of the lower mounting member 54 of the variable spring unit 42, a substantially cylindrical storage case 58 with an opening formed in the upper portion is mounted. In the storage case 58, the granular magnetic material G is dispersed and mixed. An MR (Magneto-Rheological) fluid 56 made of silicone oil is contained. Further, on the lower surface side of the upper mounting member 52 of the variable spring unit 42, on the inner side of the coil spring 50, a convex portion 60 that is inserted into the opening of the housing case 58 and immersed in the MR fluid 56 is provided. Similarly, an accommodation case 68 for accommodating the MR fluid 56 is attached to the upper surface of the lower attachment member 66 of the variable spring unit 44, and inside the coil spring 62 on the lower surface side of the upper attachment member 64 of the variable spring unit 44. Is provided with a convex portion 70 which is inserted into the opening of the housing case 68 and immersed in the MR fluid 56. Further, a housing case 78 for housing the MR fluid 56 is attached to the upper surface of the lower mounting member 76 of the variable spring unit 46, and on the lower surface side of the upper mounting member 74 of the variable spring unit 46 inside the coil spring 72. A convex portion 80 that is inserted into the opening of the housing case 78 and immersed in the MR fluid 56 is provided.

  In the MR fluid 56 accommodated in the accommodating cases 58, 68, 78 of the individual variable spring units 42, 44, 46, the granular magnetic material G is dispersed in the fluid when the magnetic field (magnetic field) is not acting. (In the state shown in FIG. 3 (A)), the liquid is fluid, but when the magnetic field M acts as shown in FIG. 3 (B), the granular magnetic bodies G gather in the fluid. By forming a cluster along the lines of magnetic force, a cluster is formed and a solid with a yield stress is formed. 3B shows a state in which the magnetic field M acts on the MR fluid 56 of the variable spring unit 46, the same applies to the other variable spring units 42 and 44. FIG. When the magnetic field M acts on the MR fluid 56 and the granular magnetic bodies G in the MR fluid 56 form clusters, the individual spring units displace the variable spring unit in the vertical direction (the upper mounting member and the lower mounting member). Even if an external force is applied (which changes the distance from the member), the displacement is blocked (locked) against the external force.

When the spring constant of the coil spring 50 is K1, the spring constant of the coil spring 62 is K2, the spring constant of the coil spring 72 is K3, and the spring constant of the variable stiffness spring 40 is K, the spring constant K has a displacement locked. If the number of variable spring units is 0,
K = 1 / (1 / K1 + 1 / K2 + 1 / K3)
When the displacement of the variable spring unit 42 including the coil spring 50 is locked,
K = 1 / (1 / K2 + 1 / K3)
When the displacement of the variable spring unit 44 including the coil spring 62 is locked,
K = 1 / (1 / K1 + 1 / K3)
When the displacement of the variable spring unit 46 including the coil spring 72 is locked,
K = 1 / (1 / K1 + 1 / K2)
When the displacement of the variable spring units 42, 44 is locked, K = K3. When the displacement of the variable spring units 42, 46 is locked, K = K2, and the displacement of the variable spring units 44, 46 is locked. K = K1 in the case, and K = ∞ when the displacements of all the variable spring units are locked. The resonance frequency ω _M of the entire vibration damping device 100 changes according to the spring constant K of the variable stiffness spring 40.

As shown in FIG. 3 (A), the coil springs 50, 62, 72 of the individual variable spring units 42, 44, 46 are connected to each other through the cable 82, and the upper end and lower end thereof are The selection drive circuit 92 is connected to a computer 88 as shown in FIG. The selection drive circuit 92 can supply drive currents independently to the coil springs 50, 62, 72. When the coil spring to be supplied with current is instructed by the computer 88, the selected drive circuit 92 Supply drive current. In the variable spring unit in which the drive current is supplied to the coil spring, the magnetic field M is generated by the drive current flowing through the coil spring, and the granular magnetic bodies G in the MR fluid 56 form clusters, as described above. The displacement is locked. Although details will be described later, the computer 88 determines that the resonance frequency ω _{M of the} vibration damping device 100 as a whole is based on the vibration detected by the vibration sensor 26, and the center frequency of the vibration component to be vibration-isolated among the detected vibrations. 0 to 3 variable spring units that lock the displacement by supplying a drive current to the coil spring are selected so as to be as close as possible (that is, the frequency of the excitation force generated by the excitation unit 108). As a result, the resonance frequency ω _M of the vibration damping device 100 as a whole is controlled so as to be synchronized with the frequency of the excitation force generated by the excitation unit 108, and the excitation force generated by the excitation unit 108 vibrates. Amplified by the entire vibration damping device 100 including the amplification unit 110.

  As shown in FIG. 4, the computer 88 of the control device 30 includes a CPU 88A, a memory 88B including a RAM, and a non-volatile storage unit 88C including an HDD (Hard Disk Drive), a flash memory, and the like. Is installed with a vibration suppression control program for performing a vibration suppression control process to be described later by the CPU 88A. This vibration suppression control program is configured to include the frequency detection program according to the present invention. When the CPU 88A executes the vibration suppression control program, the computer 88 functions as the first to third arithmetic means according to the present invention. In addition, the computer 88 functions as the frequency detection device according to the present invention, and the control device 30 and the vibration control device 100 are the vibration control device according to the seventh aspect. Will function as. The storage unit 88C stores an actuator control calculation formula for calculating the excitation force to be generated by the excitation unit 108 by the electromagnetic actuator including the electromagnetic coil 130 from the vibration detection data.

Further, as in the present embodiment, the variable rigid spring 40 has a configuration in which three variable spring units 42, 44, 46 are connected in series, and the coil springs 50, 62 of the individual variable spring units 42, 44, 46. 72, the spring constants of the variable stiffness spring 40 are changed as described above by switching the lock of the displacement in units of the individual variable spring units 42, 44, 46. The constant K changes in 2 ³ = 8, and accordingly, the resonance frequency ω _M of the damping device 100 as a whole also changes in 8 ways. In the present embodiment, the resonance frequency of the vibration damping device 100 as a whole when changing the spring constant K of the variable rigid spring 40 by switching whether or not each variable spring unit 42, 44, 46 is locked is changed. ω _M is obtained in advance by calculation or measurement. The eight resonance frequencies ω _M and the displacements of the individual variable spring units 42, 44, 46 when the resonance frequencies ω _M are each value. A lock unit-resonance frequency table associated with information indicating the presence / absence of lock is also stored in the storage unit 88C.

  Next, the operation of this embodiment will be described. When a concert or the like is performed in the hall 24 of the structure 10 according to the present embodiment and the audience jumps together in accordance with the rhythm of the music being played, the floor 18 of the hall 24 vibrates in the vertical direction. As a result, the entire upper structure including the hole 24 vibrates in the vertical direction. In the case of a normal structure, the vibration of the upper structure propagates once to the lower part of the structure via a pillar, etc., and then propagates to the surrounding building via the foundation and ground. Up and down vibrations that are likely to be uncomfortable will be induced. The vibration damping device 100 according to the present embodiment suppresses the vibration of the upper structure generated in the floor 18 of the hall 24 due to an event such as the audience jumping as a group as described above, and the structure 10 The computer 88 of the control device 30 according to the present embodiment is configured so that the CPU 88A stores the storage unit when the control device 30 is powered on. By reading and executing the vibration suppression control program from 88C, the vibration suppression control process is always executed while the control device 30 is operating. Hereinafter, the vibration suppression control process will be described with reference to FIG.

In the vibration suppression control process, first, in step 200, a predetermined value set in advance as an initial value of the center frequency ω ₀ is set. In the next step 202, it is determined whether or not the timing (sampling period T ₀ ) for taking in the result of detection of the vibration of the upper structure by the vibration sensor 26 has arrived, and step 202 is repeated until the determination is affirmed. Note that the sampling period T ₀ is set to a period sufficiently smaller than a half period of the vibration frequency to be isolated. If the determination in step 202 is affirmed, the process proceeds to step 206, vibration detection data input from the vibration sensor 26 via the amplifier 84 and the A / D converter 86 is acquired, and the acquired vibration detection data is stored in the memory 88B. Remember me.

In the next step 208 to step 218, processing for detecting the center frequency ω ₀ of the vibration to be isolated is performed. That is, first, in step 208, a digital component corresponding to applying a band-pass filter to the obtained vibration detection data is performed, so that vibration components in the frequency range of the vibration removal target (detection target) are obtained from the vibration detection data. Extract. In the present embodiment, since the vibration of the upper structure including the hole 24 generated due to an event such as the audience jumping in a group is the vibration isolation target, the vibration of the vibration isolation target is within a certain frequency range. . On the other hand, a low-frequency seismic motion X ₀ is input to the upper structure including the hole 24, or a low-frequency external force Fw caused by a wind or the like acting directly on the upper structure is input to the upper structure. In this case, the vibration of the upper structure detected by the vibration sensor 26 is a vibration in which a vibration component having a low frequency due to the seismic motion X ₀ or the external force Fw is superimposed on the vibration (component) to be subjected to vibration isolation. As described above, in step 208, by performing a digital operation corresponding to applying a band-pass filter, the vibration component in the low frequency range outside the frequency range to be isolated is added to the vibration of the superstructure represented by the vibration detection data. Even if vibration components (noise components) in the high frequency range are mixed, these noise components can be roughly removed. Note that the processing of step 208 corresponds to the first computing means described in claim 5.

  In the next step 210, the integral value B of the vibration component A in the frequency range of the vibration isolation object extracted from the vibration detection data through the processing of step 208 is calculated. The calculation of the integral value B can be realized, for example, by performing a digital operation corresponding to applying an integral filter equivalent to performing an integral on the vibration component A. The calculation of the integral value B can also be realized by performing an operation of multiplying the vibration component A by 1 / s in the Laplace transform region (where s is a complex number iω) instead of using an integral filter. The calculation at step 210 corresponds to the first calculation means according to the present invention (more specifically, the first calculation means according to claim 2).

  In the next step 212, the effective value Ae of the vibration component A in the frequency range to be vibration-isolated is calculated. As shown in FIG. 6, the effective value Ae is calculated by first calculating the square value of the vibration component A (see “the square value of the input waveform” shown in FIG. 6). A digital operation equivalent to applying a low-pass filter to the multiplication value is performed (see “the square value of the input waveform after passing through the low-pass filter” shown in FIG. 6), and 1 of the data that has undergone the above-described digital calculation. / The square value is calculated (see “the square root of the square value of the input waveform after passing through the low-pass filter” shown in FIG. 6). Of the series of operations described above, in the digital operation corresponding to applying a low-pass filter, the change in amplitude of the vibration component A is averaged by removing the component in the high frequency range. The effective value of the vibration component A is calculated by calculating the square value and the 1/2 power value (square root) before and after.

  In addition, the digital calculation corresponding to applying the low-pass filter is performed using data from the time (time t = 0) when the vibration suppression control process in FIG. 5 is started. In this embodiment, sampling is performed. The digital calculation is performed by multiplying individual data by a weighting factor set so that the weight becomes smaller as the elapsed time from the point of time increases. As a result, the influence of the individual data used for the digital calculation on the effective value Ae is reduced as the elapsed time from the sampling is increased.

  In the next step 214, the effective value Be of the integral value B calculated in the previous step 210 is calculated. As for the calculation of the effective value Be, similarly to the calculation of the effective value Ae in step 212, first, the square value of the integral value B is calculated, and the low-pass filter is applied to the square value of the calculated integral value B. Is performed by calculating a 1/2 power value of data that has undergone the digital calculation. The calculations in steps 212 and 214 correspond to the second calculation means according to the present invention (more specifically, the second calculation means according to claim 4).

In the next step 216, the effective value Ae calculated in step 212 is divided by the effective value Be performed in step 214 to calculate the vibration frequency (specifically, the angular frequency) ω of the vibration isolation target (next frequency). (See also equation (5)).
ω = Ae / Be (5)
In step 216, the angular frequency ω is calculated on the assumption that it will be used for the calculation described later. However, the angular frequency ω obtained by the equation (5) is further divided by 2π to calculate the frequency f. Needless to say, you can do it.

In the zero lock loss method, the center frequency ω is not updated until the amplitude of the vibration component crosses the zero line, so even if the frequency of the vibration to be isolated changes, this frequency Although it takes time for the change to appear in the calculation result of the angular frequency ω, the detection of the angular frequency ω in the vibration suppression control processing according to the present embodiment is more than half the frequency of the vibration isolation target frequency. When the angular frequency ω is calculated for every small sampling period T ₀ and the vibration frequency of the vibration isolation target changes, this change appears as a change in the effective values Ae and Be. It immediately appears in the calculation result, and a change in the vibration frequency of the vibration isolation target can be detected immediately. Therefore, in the control of the electromagnetic actuator (described later) performed using the calculation result of the angular frequency ω, the frequency of the vibration to be vibration-isolated is changed, for example, because the rhythm of the music played in the hall 24 has changed. Even in the case of a change, it is possible to prevent a significant control delay from occurring due to a change in the frequency of the vibration to be isolated.

  In the next step 218, the digital operation corresponding to multiplying the angular frequency ω calculated in step 216 by a low-pass filter N times is performed. N is preferably a value of 4 or more, for example, but may be a value of 3 or less. As is clear from the experimental results described later, a noise component in a relatively high frequency range is superimposed on the angular frequency ω calculated in step 216, but the noise component is removed by the above-described digital calculation. Therefore, in the control of the electromagnetic actuator (described later), it is possible to prevent the occurrence of inconvenience such as vibration of the control amount for the electromagnetic actuator.

In the next step 220 to step 228, vibration (excitation force) for canceling out the vibration component of the vibration isolation object among vibrations of the upper structure including the hole 24 detected by the vibration sensor 26 is generated by the excitation unit 108. A process of controlling to occur is performed. That is, first, in step 220, an actuator control arithmetic expression stored in advance in the storage unit 88C is read. In the present embodiment, the equation for the transfer function H ₁ (s) of the following equation (6) is used as the actuator control equation.

In the next step 222, the center frequency ω ₀ of the vibration component to be isolated and calculated and set in the previous step 218 is set as the natural frequency ω _{0 in} the actuator control calculation formula read in step 220. Note that other constants (attenuation constant h and Kg / K ₂ ) in the actuator control arithmetic expression (Expression (6)) are set in the storage unit 88C in a state preset in the arithmetic expression. do not have to. Furthermore, the damping constant h as is used a value of, for example, about _{h = 0.05, Kg / K 2} = The _{0 <Kg / K 2 <1.0} , e.g. Kg / K ₂ = 0.9 degree value is used.

In step 224, the vibration detection data stored in the memory 88B in the previous step 206 is read. In the next step 226, based on the vibration detection data read in step 224, first, the displacement of the upper structure including the hole 24 is calculated, and then the speed and acceleration of the upper structure including the hole 24 are calculated from the calculated displacement. The calculated speed of the upper structure is used as the speed V ₁ of the vibration target object, and the acceleration of the upper structure is used as the acceleration A ₁ of the vibration target object, and is read out in the previous step 220 and read in the previous step 222. The control amount for the electromagnetic actuator including the electromagnetic coil 130 is calculated by using an actuator control calculation formula in which the center frequency ω ₀ of the vibration component to be isolated is set.

In step 228, the auxiliary mass unit including the electromagnetic coil 130, the movable unit 122, and the weight 124 is opposite to the displacement of the upper structure according to the actuator control amount (virtual mass displacement X ₂ ) calculated in step 226. The direction and magnitude of the drive current supplied to the electromagnetic coil 130 by the electromagnetic coil drive circuit 90 is controlled so as to shift to the phase.

In the next steps 230 and 232, processing is performed to control the resonance frequency ω _{M of the} entire vibration damping device 100 so as to approach the center frequency ω ₀ of the vibration component to be isolated. That is, in step 230, the lock unit-resonance frequency table stored in the storage unit 88C is referred to, and among the plurality of values of the resonance frequency ω _M of the entire vibration damping device 100 stored in the table, the first one The variable spring unit lock that recognizes the value closest to the center frequency ω ₀ of the vibration component to be isolated and calculated and set in step 218 and stores it in association with the recognized value of the resonance frequency ω _M. Is read, the lock combination of the variable spring unit is recognized in which the resonance frequency ω _{M of the} vibration damping device 100 as a whole is the closest value to the center frequency ω ₀ of the vibration component to be isolated.

In step 232, the selection drive circuit 92 is controlled so that the drive current is supplied to the coil springs of the individual variable spring units corresponding to the recognized combination of locks in the variable rigid spring 40. Thereby, in each variable spring unit corresponding to the recognized combination of locks, a magnetic field is generated by the drive current flowing through the coil spring, and the granular magnetic bodies G in the MR fluid 56 to which the generated magnetic field acts form clusters. As a result, the displacement is locked. As a result, the resonance frequency ω _M of the vibration damping device 100 as a whole becomes a value closest to the center frequency ω ₀ of the vibration component to be isolated. After completing the process of step 232 returns to step 202, step 206 to step 232 is repeated every time the determination of step 202 is affirmative (every sampling period T ₀ is reached).

While the control device 30 is in operation, the above-described vibration suppression control process is always executed by the computer 88, so that the auxiliary mass unit including the electromagnetic coil 130, the movable unit 122, and the weight 124 includes the upper structure including the hole 24. The body is vibrated in the vertical direction so as to generate a vibration (vibration force) for canceling out the vibration component of the vibration isolation object. Here, in this embodiment, based on the vibration of the upper structure including the hole 24 detected by the vibration sensor 26, the electromagnetic control is performed according to the actuator control calculation formula (the calculation formula of the transfer function H ₁ (s): Formula (6)). By controlling the driving of the electromagnetic actuator including the coil 130, the vibration control device 100 controls the excitation force applied to the upper structure including the hole 24. Therefore, the upper structure including the hole 24 is (8) A behavior corresponding to the addition of a virtual dynamic absorber indicating the behavior represented by the equation, that is, the behavior represented by the equation (7) is shown.

Equation (7) is defined so that the virtual dynamic absorber exhibits a behavior that does not react to vibrations in a frequency region lower than the center frequency ω ₀ of the vibration component to be vibration-isolated. (6) When the drive of the electromagnetic actuator is controlled according to the equation, the control characteristic is that the sensitivity to the input of the frequency region near the central frequency ω ₀ of the vibration component to be isolated is not reduced, and the input of the other frequency region is reduced. Sensitivity to is greatly reduced. Therefore, even when the vibration component in the low frequency range due to the ground motion X ₀ or the external force Fw is superimposed on the vibration of the superstructure detected by the vibration sensor 26, it responds to the vibration component in the low frequency range. By driving the actuator, the actuator is driven in response to only the vibration component of the vibration isolation target, and only the vibration component of the vibration isolation target is accurate. It can be suppressed well. The maximum displacement amount (= stroke) of the actuator can be suppressed, and it is possible to achieve both improvement in performance for vibration isolation of the vibration component to be isolated, and reduction in size and configuration of the vibration damping device 100.

Further, in the vibration suppression control processing according to the present embodiment, the center frequency ω ₀ of the vibration component to be vibration-isolated is always detected, and the actuator control arithmetic expression using the detected center frequency ω ₀ is used to calculate the electromagnetic actuator. since controlling the drive, for example, when the center frequency [omega ₀ of the oscillating components of the target vibration damping for reasons such as changed rhythm of the song being played by the hole 24 is also changed, the central frequency [omega ₀ The amount of actuator control is calculated so as to follow the change of the vibration, and the vibration component of the vibration isolation target is accurately isolated (vibration controlled) regardless of the change in the center frequency ω ₀ of the vibration component of the vibration isolation target. can do.

In this embodiment, the electromagnetic actuator is driven to vibrate the auxiliary mass unit, and at the same time, the deviation of the resonance frequency ω _M of the vibration damping device 100 as a whole from the center frequency ω ₀ of the vibration component to be isolated is minimized. Thus, since the displacement of 0 to 3 variable spring units of the variable rigid spring 40 is locked, the vibration damping device 100 as a whole resonates and displaces with the displacement of the auxiliary mass unit, so that the auxiliary mass unit The excitation force generated by the excitation unit 108 due to this displacement is amplified by the entire damping device 100 at a high magnification (for example, 10 to 20 times) and then applied to the upper structure including the hole 24. As a result, the mass of the object (auxiliary mass part) displaced by the actuator can be reduced as compared with the magnitude of the vibration component to be isolated included in the vibration of the upper structure. Can be reduced, the configuration can be simplified, and the power consumption of the actuator can be reduced. Further, since the changing is also to follow the change in the center frequency [omega ₀ of the vibration component of the vibration damping subject the resonance frequency [omega _M of the whole vibration damping device 100, the vibration isolation of the vibration components of the target center frequency [omega ₀ of Regardless of the change, it is possible to maintain a state in which the excitation force generated by the excitation unit 108 is applied to the upper structure including the hole 24 after being amplified at a high magnification.

  In the above description, the configuration in which the magnetic field applied to the MR fluid 56 is generated by flowing a drive current through the coil spring of the variable spring unit is not limited to this. A magnetic field may be generated by a coil or the like. Further, the variable stiffness spring is not limited to the configuration in which the stiffness (spring constant) is changed using the MR fluid, and other known configurations such as a configuration in which the stiffness (spring constant) is changed using the air pressure. You may use the variable rigidity spring of the structure.

  Moreover, although the example which provided the damping device 100 which concerns on this invention in the middle of the pillar of the structure was demonstrated above, it is not limited to this, A damping target object is in the lower layer side of a structure. In the case where it exists, the vibration damping device according to the present invention may be provided on a pile of a structure or the like.

  In the above description, the vibration of the vibration isolation target in the vibration suppression target object is the vertical vibration (vertical direction). However, the present invention is not limited to this, and the vibration of the vibration isolation target is horizontal (horizontal). Direction) or the direction of vibration may be indefinite. Even when the direction of vibration is indefinite, a vibration damping device that suppresses vibration in the vertical direction and a vibration suppression device that suppresses vibration in the left-right direction are provided, and the vibration to be isolated is decomposed in the vertical direction and left-right direction. It is only necessary to control the operation of the vibration damping device having different vibration directions to be detected based on the detected vibrations in the respective directions.

  Further, in the above calculation (detection) of the vibration frequency of the vibration to be isolated, for the vibration component A in the vibration frequency range of the vibration isolation object extracted from the vibration detection data through digital calculation corresponding to a bandpass filter, A mode in which the integral value B is calculated, the effective value Ae of the vibration component A and the effective value Be of the integrated value B are calculated, and the ratio (Ae / Be) between the effective value Ae and the effective value Be is calculated as the angular frequency ω. As described above, the present invention is not limited to this, and the differential value C is calculated by performing a digital calculation corresponding to applying a differential filter to the vibration component A in the frequency range to be isolated. The effective value Ae of the vibration component A and the effective value Ce of the differential value C may be calculated, and the ratio (Ce / Ae) between the effective value Ae and the effective value Ce may be calculated as the angular frequency ω. This aspect corresponds to the invention described in claim 3.

  However, the calculation of the integral value B is equivalent to multiplying the vibration component A by 1 / s in the Laplace transform domain (where s is a complex number iω), and the calculation of the differential value C is s in the Laplace transform domain. Equivalent to multiplying. Here, changes in the absolute values of 1 / s and s in the frequency region are shown in FIG. 7. As is clear from FIG. 7, the absolute value of 1 / s decreases as the frequency increases. Therefore, when the vibration component A is multiplied by 1 / s in the Laplace transform region, the amplitude is attenuated when the noise component exists in the high frequency region, while the noise component exists in the low frequency region. If so, the amplitude will be amplified. Also, since the absolute value of s increases as the frequency increases, when the vibration component A is multiplied by s in the Laplace transform region, the amplitude increases when a noise component exists in the low frequency region. On the other hand, when a noise component is present in the high frequency range, the amplitude is amplified. In the vibration damping device 100 according to the present embodiment, typical noise components that are present in a low frequency range where the frequency to be controlled is about 5 to 10 Hz and are superimposed on the vibration component A are power supply noise, equipment vibration, and the like. Therefore, it is preferable to calculate the frequency using the integral value B as described in the present embodiment, since it is a vibration component in a higher frequency range (for example, about several tens of Hz).

  In the above description, the case where the vibration suppression target object is a part of a structure (building) has been described. However, the present invention is not limited to this. For example, in an electric / electronic device including a motor, vibration generated by the motor It is also possible to apply the present invention to the case where it is desired to suppress the propagation to the surroundings.

Further, the detection of the frequency according to the present invention is not limited to use in combination with vibration suppression control as described above, and it goes without saying that it can also be used alone. In addition, the detection of the frequency according to the present invention is not limited to using a signal obtained by detecting the vibration as an input signal, but may be a sine wave or an input signal showing a periodic change approximated to a sine wave. The input signal may be a signal representing a physical quantity other than vibration, or may not be a signal representing a specific physical quantity (
In the above description, the vibration control program including the frequency detection program according to the present invention has been previously stored (installed) in the storage unit 88C of the computer 88. However, the frequency detection program according to the present invention is It is also possible to provide the information recorded in a recording medium such as a CD-ROM or a DVD-ROM.

  Next, the results of experiments conducted by the inventors will be described. When the inventors of the present invention applied the present invention to actually detect the frequency of the input signal, a noise component in a relatively high frequency range was superimposed on the frequency detection result, and the detected frequency It became clear that the value fluctuated with a relatively short period.

  For this reason, the inventors of the present application, for the purpose of removing noise components in the high frequency range superimposed on the frequency detection result, are digital equivalent to applying a low-pass filter to the frequency detection result N times. The operation was repeated while changing the value of N (the number of low-pass filter processes), and an experiment was performed to compare the results. The result of this experiment is shown in FIG. As shown in FIG. 7, the frequency of the input signal was set to a value around 6.5 Hz in this experiment. As apparent from FIG. 8, when N = 2, the noise component in the high frequency region remains considerably, but when N = 3, the amplitude of the noise component in the high frequency region is considerably suppressed, and N = 4 confirms that most of the noise components in the high frequency range have been removed.

  Subsequently, in order to confirm the effect of the present invention, the inventors of the present application use an input signal whose frequency is switched at intervals of 4 seconds as shown in FIG. 9 as an example. An experiment was carried out to detect the frequency of and confirm the detection result of the frequency. In this experiment, the frequency between time t = 0 and 4 seconds was 3.0 Hz, the frequency between t = 4 and 8 seconds was 4.0 Hz, and the frequency after t = 8 seconds was 3.1 Hz. In addition, the number of times of low-pass filter processing is N = 4. The result of this experiment is shown in FIG.

  As shown in FIG. 10, when the frequency of the input signal changes from 3.0 Hz to 4.0 Hz and when the frequency of the input signal changes from 4.0 Hz to 3.1 Hz, the frequency detection result (Denoted as “estimated frequency” in FIG. 10) changes to a value that matches the changed frequency in about 1.5 seconds after the frequency of the input signal changes. As explained above, when the frequency of the detection target changes from 3.0 Hz to 4.0 Hz, the zero crossing method is likely to take a very long time of about 40 seconds to detect the frequency after the change. According to the present invention, especially when the frequency of the detection target is in a low frequency range, the time required to detect the changed frequency when the frequency of the detection target changes is compared with the zero crossing method. Can be greatly shortened.

It is a general view of the structure to which the vibration damping device concerning this embodiment was attached. (A) is a perspective view of the vibration damping device, and (B) is a cross-sectional view of the vibration damping device along the section DD ′ of (A). (A) is a schematic block diagram of a variable rigid spring, (B) is explanatory drawing which shows the magnetic field generation state in the variable spring unit provided with the displacement lock function. It is a block diagram which shows schematic structure of a control apparatus. It is a flowchart which shows the content of the vibration suppression control processing performed with the computer of a control apparatus. It is an image figure for demonstrating the calculation of an effective value. It is a diagram which shows the change of the absolute value of 1 / s and s in a frequency domain. It is a diagram which shows the result of the experiment which this inventor etc. implemented. It is a diagram which shows the result of the experiment which this inventor etc. implemented. It is a diagram which shows the result of the experiment which this inventor etc. implemented.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Structure 24 Hall 26 Vibration sensor 30 Control apparatus 56 MR fluid 88 Computer 90 Electromagnetic coil drive circuit 92 Selective drive circuit 100 Damping apparatus 108 Excitation part 110 Vibration amplification part 122 Movable part 124 Weight 128 Support member 130 Electromagnetic coil 142 Permanent magnet

Claims (9)

A first calculation means for repeatedly calculating an integral value or a differential value of an input signal indicating a sine wave or a periodic change approximated to a sine wave;
Second calculation means for repeatedly calculating the effective value of the input signal and the effective value of the integral value or the differential value calculated by the first calculation means;
Using the ratio between the effective value of the input signal calculated by the second calculating means and the effective value of the integral value or the differential value calculated by the second calculating means, the period change of the input signal is calculated. A third calculating means for repeating calculating the frequency;
A frequency detection device including:   The first computing means computes an integral value of the input signal, the second computing means computes an effective value of the integral value, and the third computing means is the input computed by the second computing means. The frequency detection device according to claim 1, wherein a value obtained by dividing an effective value of a signal by dividing an effective value of the integral value calculated by the second calculation means and 2π is calculated as the frequency.   The first calculation means calculates a differential value of the input signal, the second calculation means calculates an effective value of the differential value, and the third calculation means calculates the differentiation calculated by the second calculation means. The frequency detection device according to claim 1, wherein a value obtained by dividing an effective value of the value by an effective value of the input signal calculated by the second calculation means and 2π is calculated as the frequency.   The second calculation means calculates a square value for an input signal to be calculated for an effective value or the integral value or the differential value, and removes a signal component in a frequency range equal to or higher than a predetermined frequency. The effective value of the input signal of the said effective value calculation object, the said integral value, or the said derivative value is calculated by performing a process and calculating a 1/2 power value, The any one of Claims 1-3 The described frequency detection device.   The first calculating means calculates a signal component out of a predetermined frequency range including a frequency to be detected from the input signal before calculating the integral value or the differential value with respect to the input signal. The frequency detection apparatus according to any one of claims 1 to 4, wherein a band-pass filter process for removal is performed.   The third calculation means performs N times (N ≧ 1) low-pass filter processing for removing a signal component in a frequency range equal to or higher than a predetermined frequency higher than the detection target frequency from the calculation result of the frequency. The frequency detection device according to any one of claims 1 to 5. Detecting means for detecting vibration of a vibration control target object having a spring and a damper interposed between the reference object and the reference object;
The vibration detection device according to any one of claims 1 to 6, wherein the vibration detection signal output from the detection means is used as the input signal, and the vibration frequency of a vibration to be controlled is detected.
A vibration control actuator capable of applying an excitation force to the vibration target object to suppress vibration of the vibration target object;
Control means for controlling the excitation force applied to the vibration suppression target object by the vibration suppression actuator based on the vibration frequency of the vibration suppression target object detected by the frequency detection device;
Damping device including. Calculate the integral value or derivative value of the input signal showing the sine wave or periodic change approximated to the sine wave,
Calculate the effective value of the input signal, and the effective value of the integral value or the differential value of the input signal,
A frequency detection method for repeatedly calculating a frequency of a periodic change of the input signal using a ratio between an effective value of the input signal and an effective value of the integral value or the differential value of the input signal. Computer
A first calculation means for repeatedly calculating an integral value or a differential value of an input signal indicating a sine wave or a periodic change approximated to a sine wave;
Second calculation means for repeatedly calculating the effective value of the input signal and the effective value of the integral value or the differential value calculated by the first calculation means;
And the period of the input signal using a ratio between the effective value of the input signal calculated by the second calculating means and the effective value of the integral value or the differential value calculated by the second calculating means. A frequency detection program that functions as third calculation means that repeats calculating the frequency of change.

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