KR102637551B1 - Active dynamic absorber using negative stiffness phenomenon - Google Patents

Abstract

The present invention relates to an active absorber using the negative stiffness phenomenon, and more specifically, to an active absorber using a leaf spring structure configured to generate a negative stiffness phenomenon by appropriate arrangement. .
According to the present invention, by applying a leaf spring structure in which a plurality of leaf springs are arranged to generate a negative stiffness phenomenon, an active type that can be implemented to generate a stress sufficiently smaller than the strength allowed for the leaf spring while maintaining low rigidity. Provides a reducer.

Description

Active dynamic absorber using negative stiffness phenomenon}

The present invention relates to an active absorber using the negative stiffness phenomenon, and more specifically, to an active absorber using a leaf spring structure configured to generate a negative stiffness phenomenon by appropriate arrangement. .

In order to construct an active reducer, it is advantageous to induce low stiffness. Coil springs are mainly used as existing mechanical parts that induce rigidity, but in general, due to their structural characteristics, in order to maintain a low natural frequency, if low rigidity coil springs of 10 Hz or less are used, the spring cannot overcome the load and is completely compressed. The function cannot be maintained or damage occurs. In addition, in order to create low rigidity, a long spring is required, which takes up a large space, making it difficult to satisfy design results of a practical size.

As a way to overcome this, leaf springs can be used. However, when using a general leaf spring, it remains a very difficult task to generate a stress that is sufficiently smaller than the strength allowed for the leaf spring while maintaining low rigidity in order to function as an effective active reducer. .

KR 10-1266831 B1

The present invention was created to solve this problem, by applying a leaf spring structure in which a plurality of leaf springs are arranged to generate a negative stiffness phenomenon, while maintaining low rigidity, the strength is sufficiently smaller than the allowable strength of the leaf spring. The purpose is to provide an active reducer that can be implemented to generate stress.

In order to achieve this purpose, a plate spring structure using the negative stiffness phenomenon according to the present invention includes a first tuning mass connected to the plate spring structure; A support portion coupled to the edge portion of the leaf spring to support the leaf spring; a first leaf spring whose edge (hereinafter referred to as 'first edge portion') is coupled to and supported by the support portion, and on which a pre-displacement is applied by at least a portion of the total tuning mass including the mass of the first tuning mass portion; And, an edge (hereinafter referred to as a 'second edge part') is coupled to and supported by the support part and is in contact with the first edge part, is located below the first leaf spring, and is preset by at least a portion of the total tuning mass. It includes a second leaf spring to which displacement is applied, wherein a negative stiffness phenomenon is generated in at least one of the first leaf spring and the second leaf spring due to the behavior of the entire tuning mass, and the total tuning mass is If there is another tuned mass unit (hereinafter referred to as 'second tuned mass unit') connected to the spring structure, the mass is the sum of the mass of the first tuned mass unit and the mass of the second tuned mass unit, and is connected to the leaf spring structure. If there is no other tuning mass part, it is the mass of the first tuning mass part.
The leaf spring structure has an edge (hereinafter referred to as 'third edge portion') coupled to and supported by the support portion, is located below the second leaf spring, and has a pre-displacement caused by at least a portion of the total tuning mass. a third leaf spring applied; And, an edge (hereinafter referred to as 'fourth edge part') is coupled to and supported by the support part, is in contact with the third edge part, is located below the third leaf spring, and is pre-aligned by at least a portion of the total tuning mass. It may further include a fourth leaf spring to which displacement is applied, and a negative stiffness phenomenon may be generated in at least one of the third leaf spring or the fourth leaf spring due to the behavior of the entire tuned mass.
The first tuning mass portion is provided in at least one of the spaces between each leaf spring of the leaf spring structure, each of which has an upper surface in contact with a lower surface of the upper leaf spring and a lower surface of which is an upper surface of the lower leaf spring. It may include a liner that is in contact with and maintains a certain gap between the upper leaf spring and the lower leaf spring.
According to another aspect of the present invention, an active absorber using a negative stiffness phenomenon includes the leaf spring structure using the negative stiffness phenomenon; a second tuned mass connected to the leaf spring structure; It includes an actuator that provides force between the entire tuning mass portion and the lower absorption object, wherein the entire tuning mass portion includes: a first tuning mass portion of the leaf spring structure; and the second tuning mass part, wherein the second tuning mass part means 'another tuning mass part (hereinafter referred to as 'second tuning mass part')' described in the configuration of the leaf spring structure.
The actuator includes a voice coil through which a current controlled by a controller flows; And, a permanent magnet located inside the voice coil may be provided.
The second tuning mass unit may include the permanent magnet.
A negative stiffness phenomenon may occur in the leaf spring structure due to the behavior of the mass of the entire tuning mass (hereinafter referred to as 'total tuning mass').

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According to the present invention, by applying a leaf spring structure in which a plurality of leaf springs are arranged to generate a negative stiffness phenomenon, an active type that can be implemented to generate a stress sufficiently smaller than the strength allowed for the leaf spring while maintaining low rigidity. It has the effect of providing a reducer.

1 is a diagram showing the structures of a passive reducer and an active reducer.
Figure 2 is a diagram for comparing the performance of a passive reducer and an active reducer.
Figure 3 is a diagram showing the structure of a voice coil motor used as an actuator.
Figure 4 is a diagram illustrating a simulation model for confirming the effect of the exciting force generated from the actuator on the object to be absorbed.
Figure 5 is a diagram showing the acceleration response of the absorption object due to the input of the actuator.
Figure 6 is a diagram showing the shape and equivalent stiffness of a plate spring.
Figure 7 is a diagram showing the mechanical properties of SM45C, a material used in leaf springs.
Figure 8 is a diagram showing analysis results according to the number of leaf spring patterns.
Figure 9 is a diagram showing the analysis results of reinforcing the stress concentration part of a four-layer leaf spring with a pattern number of 11.
Figure 10 is a diagram showing the results of natural vibration analysis of an active absorber when the mass is designed to be 2 kg.
Figure 11 is a diagram showing a quadruple leaf spring structure.
Figure 12 is a diagram showing the structure of an active reducer using a quadruple leaf spring structure.
Figure 13 is a diagram for explaining the buckling phenomenon occurring in a beam.
Figure 14 is a diagram showing a quadruple leaf spring structure using the negative stiffness phenomenon.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately use the concept of terms to explain his or her invention in the best way. It must be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle of definability. Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing this application, various alternatives are available to replace them. It should be understood that equivalents and variations may exist.

1 is a diagram showing the structures of a passive reducer and an active reducer.

An absorber (Dynamic Absorber) or TMD (Tuned Mass Damper) is a vibration control device that is additionally attached when a structure generates a resonance phenomenon where the natural frequency and external excitation force match. Additional devices are attached without changing the existing structure. This is a device that improves the vibration suppression performance of the structure.

The passive absorber in Figure 1(a) uses a passive element that does not receive energy from the outside, selects a tuned mass or additional mass of an appropriate size (hereinafter referred to as 'tuned mass') m _tuned , and installs the structure. It is implemented by designing and attaching stiffness (K _optimal ) and damping (C _optimal ) considering the characteristics of .

The active extractor of Figure 1(b) is a vibration suppression device that has better performance and convenience of tuning by attaching a sensor and an actuator to a passive extractor and implementing an algorithm through a controller. Instead of stiffness (K _optimal ) and damping (C _optimal ) with optimal parameter values, it has an appropriate stiffness K _a , and the actuator performs control operations using the signal received from the sensor to determine the mass (M) of the absorption object. Better performance can be achieved by supplying an appropriate force (f) between ) and the tuned mass m _tuned of the active absorber. The illustrated exhaust object refers to various equipment and a base table on which such equipment is placed, and its total mass is M. A vibration isolator consisting of a spring (k) and a damper (c) is provided at the bottom.

Figure 2 is a diagram for comparing the performance of a passive reducer and an active reducer.

Figure 2(a) is the impulse response for the case without an absorber (without TMD), a passive absorber (Optimal TMD), and an active absorber (Active TMD), respectively, and Figure 2(b) shows the amplitude ( Shows a Bode plot for magnitude and phase. Referring to the drawing, the active absorber shows excellent performance with the shock response disappearing faster than the passive absorber and the peak almost disappearing in terms of frequency.

Figure 3 is a diagram showing the structure of a voice coil motor used as an actuator.

A voice coil motor is a linear actuator that includes a coil and a permanent magnet inside the coil, and can control the driving force by controlling the current flowing in the coil. Since the driving force of these actuators is controlled by changing the control signal supplied from the controller, it is important to select an appropriate stiffness k _a in the design of the active absorber.

Figure 4 is a diagram illustrating a simulation model for confirming the effect of the exciting force generated from the actuator on the object to be absorbed.

The active absorber comes down to the problem of determining the tuned mass m _tuned and the stiffness k _a . In general, the larger m _tuned , the more effective it is, but if it has a large value based on the mass M of the absorption object using an active absorber, problems in realistic implementation may arise, so it is generally set at 5 to 10% of M. Therefore, determination of stiffness k _a remains an important issue.

Figure 4 is a simulation model to check the effect of stiffness k _a and exciting force generated from the actuator on the mass M of the structure. The structure placed at the bottom is assumed to have 1 degree of freedom, and the mass is set to 100 kg and the natural frequency is set to 5 Hz. This is because low natural frequencies are advantageous for vibration isolation performance, so most vibration isolation tables use low-rigidity materials that induce low natural frequencies. At this time, the additional mass m _tuned , which constitutes the active absorber, is set to 5 kg, and the stiffness K _a is set so that the natural frequencies f _na of the TMD are 5 Hz, 10 Hz, and 20 Hz. At this time, the low natural frequency is due to low rigidity. Using this model, the acceleration of the mass M of the absorbing object relative to the input of the actuator can be expressed as a frequency response.

Figure 5 is a diagram showing the acceleration response of the absorption object due to the input of the actuator.

If a large acceleration occurs with respect to the input of the same actuator, the exciting force generated from the actuator will have a significant impact on the structure, which can be judged as a desirable design result. Figure 5 shows the analysis results of this model. It can be seen that the acceleration of the structure due to the driving of the actuator shows a larger value as f _na is lower in the band of around 5 Hz, which is the natural frequency of the structure of interest. In other words, if the stiffness of the active absorber is high, it has less influence on the natural frequency of the structure that needs to be controlled, making it difficult to expect good control characteristics. In contrast, the low rigidity of the active extractor shows a large driving force in the actuator of interest around 5 Hz, so good control characteristics can be expected.

Figure 6 is a diagram showing the shape and equivalent stiffness of a plate spring, and Figure 7 is a table showing the mechanical properties of SM45C, a material used in the plate spring.

Figure 6(a) is a diagram showing a beam supported at both ends and its equivalent stiffness in a mathematical manner, and Figure 6(b) is a diagram showing the shape of the leaf spring used in the present invention as seen from above.

As previously mentioned, in order to construct an active absorber, it is advantageous to induce low stiffness. Coil springs are mainly used as existing mechanical parts that induce rigidity, but in general, due to their structural characteristics, in order to maintain a low natural frequency, if low rigidity coil springs of 10 Hz or less are used, the spring cannot overcome the load and is completely compressed. The function cannot be maintained or damage occurs. In addition, in order to create low rigidity, a long spring is required, which takes up a large space, making it difficult to satisfy design results of a practical size.

Therefore, in order to maintain low rigidity in a small space, a leaf spring 1110 as shown in Figure 6 below is used. This is a structure in which the load points are aligned by using multiple structures that induce appropriate rigidity using double-end support beams, and is designed in a rotation type to save space. Referring to Figure 6(a), the equivalent stiffness of the double end support beam is determined by the length (l), the elastic modulus of the material (E), and the area moment of inertia of the cross section (I). Additionally, the vertical stress that occurs at this time is determined by the bending formula derived based on Hooke's law.

The leaf spring 1110 forms a plurality of patterns 100 formed in the shape of grooves on a plate. The leaf spring 1110 performs the function of a spring by generating displacement in the up and down directions due to the pattern 100 when force in the up and down directions is applied.

For the design of the leaf spring 1110, the thickness of the plate, the width of the beam, the number of beams, etc. are used as design parameters. You can design one beam and determine its number by copying the pattern in the direction of rotation. The applied load is selected as 200 N considering the tuning mass of the active extractor, the force of the actuator, and the safety factor, and an appropriate shape design is performed by performing various analyzes. It can be seen from the table in FIG. 7 that SM45C, the material used, has a tensile strength of 490 MPa. That is, a large amount of displacement is induced in response to the applied load, so that low rigidity is maintained while the generated stress is maintained below the allowable tensile strength.

Figure 8 is a diagram showing analysis results according to the number of leaf spring patterns.

Figure 8(a) is the analysis result of a single leaf spring with a thickness of 4 mm and using one plate, Figure 8(b) is the analysis result of a double leaf spring using two plates, and Figure 8(c) is the analysis result of four plates. This is the analysis result of a quadruple leaf spring using plates. In each table, 'Pattern' refers to the number of patterns, 'Disp.' refers to the maximum vertical displacement of the leaf spring, and 'Stress' refers to the stress received by the leaf spring. Also, in Figures 8(b) and (c), 't' refers to the thickness of each plate. Each table is the result of static analysis while changing the number of patterns.

In the single leaf spring of Figure 8(a), when the pattern is 8, a displacement of 12.8 mm occurs, and the stress at that time has a value much larger than the allowable strength.

In the double leaf spring of Figure 8(b), the parallel support structure results in the stiffness of each spring being added, so to create the same stiffness as in the case of a single leaf spring, two leaf springs with half the stiffness must be used. do.

The analysis results are as shown in the table in Figure 8(b). When the thickness is 1.5 mm and the pattern is 5, the displacement is 25.6 mm, which means it has very low rigidity, but it cannot be used because the stress greatly exceeds the allowable stress. However, when the thickness is 2.0 mm and the pattern is 8, it has a displacement of 16.0 mm, but the stress is smaller than that of a single leaf spring with a displacement of 12.8 mm.

In other words, it can be confirmed that structural design with greater displacement and lower stress is possible by adjusting the pattern and thickness. Additionally, double-structured parallel leaf springs are advantageous in terms of displacement-to-stress ratio. Therefore, better results can be expected by expanding the leaf spring to quadruple.

Figure 8(c) shows the results of arranging leaf springs in a quadruple parallel structure and analyzing the displacement and stress according to changes in various patterns. The table in Figure 8(c) shows the results of fixing the thickness of each plate to 1.5 mm and changing only the number of patterns.

It can be seen that as the number of patterns increases, the displacement increases proportionally, but the stress is not proportional. It can be seen that the stress is the smallest when the pattern is 10, but the displacement increases significantly compared to single or double patterns. Compared to the stress of 709 MPa at the 16.0 mm displacement of the double structure, the displacement increased to 19.3 mm in pattern 10 of the quadruple structure, but the stress decreased significantly to 554 MPa.

The voice coil motor of the actuator used in this design has a stroke of +/- 15 mm, so when the pattern is 11 in the quadruple structure, the displacement of 21.2 mm is not implemented. Therefore, even if this was adopted, the stress generated was estimated to be below the allowable strength, so this was selected, and the process of confirming the stress using finite element analysis was repeated while reinforcing the local stress generation area.

Figure 9 is a diagram showing the analysis results of reinforcing the stress concentration part of a four-layer leaf spring with a pattern number of 11.

The analysis results are shown by reinforcing the area where stress is concentrated on a four-layer leaf spring with a thickness of 1.5 mm and a number of patterns of 11. It can be seen that for a load of 200 N, the displacement is 21.2 mm and the stress at that time has decreased to 335 MPa. In addition, as mentioned earlier, the actuator's voice coil motor has a stroke of +/-15 mm, so the actual stress generated is reduced proportionally and can be estimated at 237 MPa, which is about half the allowable strength, with a safety factor of 200. You can confirm that the design has no problems with operation by using the %.

Figure 10 is a diagram showing the results of natural vibration analysis of an active absorber when the mass is designed to be 2 kg.

It can be confirmed that the natural frequency of mode 1 in Figure 10(a) shows a vertical mode shape and has a natural frequency of 10.4 Hz.

FIG. 11 is a diagram showing the quadruple leaf spring structure 1100, and FIG. 12 is a diagram showing the overall structure of the active reducer 1000 to which the quadruple leaf spring structure 1100 is applied.

The support portion 1130 is connected to the mass M of the vibration control absorbing object, and the middle portion supported by the leaf spring 1110 adjusts the gap between the leaf springs 1110 using several liners 1120. there is. This part corresponds to the tuning mass part of the active extractor 1000 to which the driving force of the actuator 1200 is applied. Even when the actuator is not driven, all four leaf springs 1110 sag in the downward direction due to static load due to gravity.

FIG. 12(a) is a perspective view showing a cross-section of the active reducer 1000, and FIG. 12(b) is a perspective view showing the shape of the active reducer.

In FIG. 12, the tuned mass m _tuned is the sum of the mass of the liner 1120 and the mass of the permanent magnet 1220 of the voice coil motor 1200, which is an actuator. Meanwhile, the coil unit 1210 of the voice coil motor is fixed to the bottom and is fixed to the absorption object M that is the object of vibration control.

It was confirmed that the active absorber 1000 adopting the quadruple leaf spring structure 1100 of FIG. 11 had a natural frequency of 10.9 Hz in the initial state, and the dynamic stiffness ka was confirmed to be 9380.9 N/m.

Hereinafter, the principle applied to reduce the rigidity of the quadruple leaf spring structure 1100 will be described with reference to FIG. 13, and the quadruple leaf spring structure 1100 of the present invention to which such principle is applied will be described with reference to FIG. 14. Let me explain.

Figure 13 is a diagram for explaining the buckling phenomenon occurring in a beam.

Negative stiffness means that the stiffness value is negative at F=kx, which represents the relationship between spring stiffness (k), external force (F), and displacement (x), and is considered a structure that cannot be physically achieved in general mechanical structures. However, as shown in FIG. 13, methods for implementing the method using the buckling phenomenon occurring in long slender beams have been studied.

(1) in Figure 13(a) is the initial state of a beam with both ends fixed vertically, and a line load is already applied and it starts in a buckling state. At this time, if the force F _t applied in the horizontal direction to the center is small, it is obvious that it has positive stiffness for a very small size. This corresponds to section (1) in the graph of Figure 13(b). The stiffness determined by the displacement of the horizontal axis and the force of the vertical axis becomes the slope, which has a positive sign.

However, when a continuous load is applied and the state transitions to (2) in Figure 13(a), it moves from the buckling state to the state (3) in Figure 13(a) by magnetic force. In other words, in the transition section, even if the small external force F _t becomes negative, it moves to state (3), so it shows the effect of showing the phenomenon of negative stiffness. This shows section (2) in the graph of Figure 13(b), and the slope has a negative sign. Therefore, the displacement section showing this transition characteristic is a structure with negative stiffness.

FIG. 14 is a diagram illustrating a quadruple leaf spring structure 1100 using the negative stiffness phenomenon.

In the initial state of FIG. 14(a), if each leaf spring 1110 is supported in a way that touches the support part 1130, a line load is naturally applied by the liner 1120, and the shape behaves as shown in FIG. 14(b). I do it. At this time, the expression 'contact' is not necessarily limited to 'meeting' each leaf spring 1110 at the support portion 1130 as shown in FIG. 14, but encompasses the meaning of being sufficiently close to each other, and the same applies hereinafter.

That is, the part where leaf spring 1 (1111) is coupled to the support part 1130 and the part where leaf spring 2 (1112) is coupled to the support part 1130 contact each other at the support part 1130, as shown in FIG. 14(a). , the portion where leaf spring 3 (1113) is coupled to the support portion 1130 and the portion where leaf spring 4 (1114) is coupled to the support portion 1130 are in contact with each other at the support portion 1130 as shown in FIG. 14(a). is formed by

When the structure in Figure 14(a) is deformed under a load from a mass, it behaves in the same shape as Figure 14(b). At this time, the liner 1120 constitutes a part of the tuning mass that causes such prior displacement, and the permanent magnet 1220 of the actuator 1200 as described above with reference to FIG. 12 also forms part of the tuning mass. That is, from the top, leaf spring 1 (1111) and leaf spring 3 (1113) are placed in a transition section in the negative stiffness structure as described with reference to FIG. 13, thereby inducing negative stiffness. However, leaf spring 2 (1112) and leaf spring 4 (1114) perform behavior with general positive stiffness, and the stiffness of the entire system is the sum of the stiffnesses of the individual leaf springs (1111, 1112, 1113, and 1114). Therefore, it cannot always be considered negative stiffness. However, this results in lower rigidity compared to the general quadruple leaf spring installation structure. In addition, the size of the line load can be easily adjusted depending on the thickness of the liner 1120 inserted between the leaf springs, resulting in a structure that can be adjusted to an appropriately low rigidity.

Here, when additional load is applied and leaf spring 1 (1111) and leaf spring 3 (1113) exceed the transition section, positive rigidity is again induced, so the size of the rigidity is again the same size as the installation structure of a general quadruple leaf spring. have it Therefore, in order to maintain low rigidity, set it to operate only within the transition section.

The quadruple leaf spring structure 1100 using the negative stiffness phenomenon formed in this way was measured to have a natural frequency of 7.9 Hz in the static deflection state of Figure 14(b), and When the dynamic stiffness of the active extractor (1000) to which this leaf spring structure (1100) is applied is extracted considering the tuned mass m _tuned , it is confirmed that ka is 4927.7 N/m, which is 44.5% of the stiffness compared to the active extractor of Figure 12. It can be seen that the stiffness has decreased. From this, it can be confirmed that when the quadruple leaf spring structure 1100 using the negative stiffness phenomenon of FIG. 14 is mounted on the active extractor 1000, it has a very effective effect.

1000: Active reducer
1100: plate spring structure
1110: leaf spring
1111: Leaf spring 1
1112: leaf spring 2
1113: leaf spring 3
1114: Leaf spring 4
1120: liner
1130: support part
1200: actuator
1210: voice coil
1220: permanent magnet

Claims (7)

A plate spring structure that utilizes the phenomenon of negative stiffness,
a first tuned mass connected to the leaf spring structure;
A support portion coupled to the edge portion of the leaf spring to support the leaf spring;
a first leaf spring whose edge (hereinafter referred to as 'first edge portion') is coupled to and supported by the support portion, and on which a pre-displacement is applied by at least a portion of the total tuning mass including the mass of the first tuning mass portion; and,
An edge (hereinafter referred to as a 'second edge part') is coupled to and supported by the support part and is in contact with the first edge part, is located below the first leaf spring, and has a pre-displacement caused by at least a portion of the total tuning mass. Second leaf spring loaded
Including,
A negative stiffness phenomenon is generated in at least one of the first leaf spring and the second leaf spring due to the behavior of the entire tuned mass,
The total tuned mass is,
If there is another tuning mass part (hereinafter referred to as 'second tuning mass part') connected to the leaf spring structure, the mass is the sum of the mass of the first tuning mass part and the mass of the second tuning mass part,
If there is no other tuning mass connected to the leaf spring structure, the mass of the first tuning mass is,
Leaf spring structure that utilizes the negative stiffness phenomenon. In claim 1,
A third leaf spring whose edge (hereinafter referred to as 'third edge portion') is coupled to and supported by the support portion, is located below the second leaf spring, and has a pre-displacement applied by at least a portion of the total tuning mass. ; and,
An edge (hereinafter referred to as 'fourth edge part') is coupled to and supported by the support part and is in contact with the third edge part, is located below the third leaf spring, and has a pre-displacement caused by at least a portion of the total tuning mass. 4th leaf spring loaded
It further includes,
A negative stiffness phenomenon occurs in at least one of the third leaf spring or the fourth leaf spring due to the behavior of the entire tuned mass.
A leaf spring structure using the negative stiffness phenomenon characterized by . In claim 1 or claim 2,
The first tuning mass unit,
It is provided in at least one of the spaces between each leaf spring of the leaf spring structure, and each has an upper surface in contact with the lower surface of the upper leaf spring and a lower surface in contact with the upper surface of the lower leaf spring, and the upper surface is in contact with the upper surface of the leaf spring. A liner that maintains a certain gap between the spring and the lower leaf spring.
A leaf spring structure using a negative stiffness phenomenon comprising a. An active absorber that utilizes the phenomenon of negative stiffness,
The leaf spring structure of claim 1 utilizing the negative stiffness phenomenon;
a second tuned mass connected to the leaf spring structure;
An actuator that provides force between the entire tuned mass and the lower absorption object.
Including,
The entire tuned mass portion is,
a first tuned mass portion of the leaf spring structure; and
The second tuned mass portion
Includes,
The second tuned mass unit,
Means 'another tuned mass part (hereinafter referred to as 'second tuned mass part')' described in claim 1,
Active reducer that utilizes the negative stiffness phenomenon. In claim 4,
The actuator is,
A voice coil carrying a current controlled by a controller; and,
Permanent magnet located inside the voice coil
An active reducer that utilizes the negative stiffness phenomenon, characterized in that it has a. In claim 5,
The second tuned mass unit,
The permanent magnet
An active reducer that utilizes the negative stiffness phenomenon, comprising: In claim 4,
A negative stiffness phenomenon occurs in the leaf spring structure due to the behavior of the mass of the entire tuning mass (hereinafter referred to as 'total tuning mass').
An active absorber that utilizes the negative stiffness phenomenon characterized by .