JP2002081498A - Vibration resisting method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration resisting method and its device having high vibration resistance for precise machining applications by securing high rigidity for direct acting disturbance without impairing vibration insulating performance to the ground motion disturbance. SOLUTION: Vibration resistance is conducted by using a spring 5 between a floor 6 and an intermediate block 1 and a magnetic floating mechanism having a zero-power property formed with a permanent magnet 3 and an electromagnet 4 between the intermediate block 1 and a vibration resistant table 2. With spring vibration resistance obtained by using the spring 5 between the floor 6 and the intermediate block 1 and the vibration resistance obtained by using the magnetic floating mechanism between the intermediate block 1 and the vibration resistant table 2, high rigidity is secured for the direct acting disturbance and good vibration resistance capability is provided for precise machining applications without impairing vibration insulating performance to the ground motion disturbance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to vibration isolation of equipment, and more specifically to passive vibration isolation for the purpose of insulating ground motion disturbances as well as active vibration isolation capable of dealing with sprung disturbances. Related to a vibration method and a device thereof,
It is used in machine tools such as machines and machining centers, as well as various devices typified by steppers in the IC industry, and insulates machining tables and the like from disturbances to achieve high-precision machining.

[0002]

2. Description of the Related Art At present, a semiconductor device manufacturing system and an ultra-small area measuring system are rapidly increasing in accuracy and performance, and in these systems, anti-vibration and anti-vibration for removing disturbances such as vibrations. The importance of the device is increasing. Vibration disturbances to be removed by the anti-vibration device can be broadly classified into ground disturbance due to vibration from the installation floor and linear motion disturbance input on the spring of the device. For the latter, a highly rigid mechanism is suitable. FIG. 11 shows a conventional passive vibration isolation system that insulates ground motion disturbance and isolates vibrations. When the spring constant k is reduced to lower the spring stiffness in order to reduce the vibration transmission rate from the floor 36, It becomes weak against disturbance on the spring such as a change in mass Δm on the vibration isolation table 32 (mass m) and a change in load acting on the vibration isolation table 32. Conversely, it is necessary to increase the spring stiffness to some extent against the disturbance on the spring. Conflicting characteristics such as a low-rigidity mechanism for absorbing such disturbances and a high-rigidity mechanism for maintaining position and orientation are required.

In general, when two springs 35-1 and 35-2 having positive spring constants k ₁ and k ₂ are connected in series to constitute one vibration isolation mechanism, the spring constant is obtained by the following equation. . k _c = k ₁ k ₂ / (k ₁ + k ₂ ) (1) That is, when springs having a normal positive spring constant are connected in series, the spring constant formed by the connection is always smaller than the spring constant before the connection. It becomes. Therefore, it is extremely difficult to secure high rigidity against disturbances on the spring such as mass change and vibration with these conventional vibration damping devices using only springs. Was done.

FIG. 12 shows the principle of a general active vibration isolation control apparatus. The controller 115 controls the vibration of the vibration isolation table 110 based on a detection signal from an acceleration sensor 114 installed on the vibration isolation table 110. Control input for suppressing the spring 11 is calculated based on the obtained control input.
The anti-vibration control is performed by operating the actuator 113 installed in parallel with the attenuator 1 and the attenuator 112.

[0005]

However, such an approach is based on the premise that vibrations of the vibration isolation table and the floor are accurately detected. It is necessary to use a servo-type acceleration sensor that can detect it, so it becomes expensive and, depending on the servo-type acceleration sensor employed, the rigidity against linear motion disturbance is not yet sufficient, and complete vibration isolation performance is secured. Was insufficient.

Therefore, the present invention solves the problems of the conventional vibration isolation method and the conventional vibration isolation device, and secures high rigidity against linear motion disturbance without impairing the vibration insulation performance against ground motion disturbance, and achieves a high vibration isolation function. It is an object of the present invention to provide an anti-vibration method and an apparatus for realizing precision processing and the like by utilizing the above.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a linear motion disturbance generated on a device by connecting a support mechanism having a positive spring characteristic and a support mechanism having a negative spring characteristic in series. , And has substantially infinite rigidity, and is insulated from vibration with respect to the floor. Further, the present invention provides a spring disposed between the floor and the first member to insulate vibration transmitted from the floor to the first member,
A vibration transmitted from the first member to the second member is insulated by disposing a magnetic levitation mechanism having a zero power characteristic including a permanent magnet and an electromagnet between the member and the second member. And The present invention also provides an intermediate table supported on the floor by a spring having a predetermined positive spring constant, and a permanent magnet and an electromagnet for the intermediate table to provide a zero power characteristic of a predetermined negative spring constant. And a vibration isolation table supported by a magnetic levitation mechanism. Further, the present invention is characterized in that a damping device having a predetermined damping rate is provided between the floor and the intermediate table in parallel with the spring. Further, the present invention is characterized in that the attraction force of the electromagnet provided on the intermediate table is increased or decreased according to the increase or decrease of the load acting on the vibration isolation table provided with the permanent magnet. Further, according to the present invention, the attraction force of the composite magnet composed of the electromagnet and the permanent magnet provided on the intermediate table to the vibration isolation table provided with the ferromagnetic material is increased or decreased according to the load applied to the vibration isolation table. It is characterized in that it is configured to increase or decrease. Further, the present invention is characterized in that the electromagnet provided on the vibration isolation table is configured to increase or decrease the attraction force to the intermediate table provided with the permanent magnet in accordance with the increase or decrease of the load acting on the vibration isolation table. I do. Further, the present invention provides a composite magnet comprising an electromagnet and a permanent magnet provided on the vibration isolation table,
It is characterized in that the suction force on the intermediate table provided with the ferromagnetic material is increased or decreased according to the increase or decrease of the load acting on the vibration isolation table. Also, the present invention provides a magnetic levitation mechanism having a zero power characteristic composed of a permanent magnet and an electromagnet between the floor and the first member to insulate vibration transmitted from the floor to the first member, The vibration transmitted from the first member to the second member is insulated by disposing a spring between the first member and the second member. Further, the present invention provides an intermediate table supported by a magnetic levitation mechanism composed of a permanent magnet and an electromagnet with respect to a floor and having a zero power characteristic of a predetermined negative spring constant, and a predetermined positive spring mounted on the intermediate table. And a vibration isolation table supported by a spring having a constant. Further, the present invention is characterized in that a damping device having a predetermined damping rate is provided between the intermediate table and the vibration isolation table, in parallel with the spring. Further, the present invention is characterized in that the attraction force of the electromagnet installed on the floor side to the intermediate table provided with the permanent magnet is increased or decreased according to the increase or decrease of the load acting on the intermediate table. Further, the present invention provides a composite magnet comprising an electromagnet and a permanent magnet installed on the floor side,
It is characterized in that the suction force acting on the intermediate table provided with the ferromagnetic material is increased or decreased in accordance with the increase or decrease of the load acting on the intermediate table. Further, the present invention is characterized in that the attraction force of the electromagnet provided on the intermediate table with respect to the permanent magnet installed on the floor is increased or decreased according to the increase or decrease of the load acting on the intermediate table. Further, the present invention provides a composite magnet composed of an electromagnet and a permanent magnet provided on the intermediate table, wherein the attractive force acting on the ferromagnetic material installed on the floor side is increased or decreased according to the load applied to the intermediate table. It is characterized in that it is configured to increase or decrease. The present invention also provides a floor and a first floor.
A spring is disposed between the first and second members to insulate vibration transmitted from the floor to the first member, and a negative spring is provided between the first and second members by a support mechanism including an actuator and a controller. By imparting characteristics, vibration transmitted from the first member to the second member is insulated. Further, according to the present invention, there is provided an intermediate table supported on a floor by a spring having a predetermined positive spring constant, and an intermediate table supported by a supporting mechanism having an actuator and a control device and having a predetermined negative spring constant. And a vibration isolation table. Further, the present invention is characterized in that a damping device having a predetermined damping rate is provided between the floor and the intermediate table in parallel with the spring. Further, the present invention is characterized in that a spring having a predetermined spring constant and a damping device having a predetermined damping rate are provided between the intermediate table and the vibration isolation table in parallel with the actuator. Further, the invention is characterized in that the extension of the actuator provided on the intermediate table is increased or decreased in accordance with the increase or decrease of the load acting on the vibration isolation table. Further, according to the present invention, a negative spring characteristic is provided between the floor and the first member by a support mechanism including an actuator and a control device, and the first member is moved from the floor to the first member.
The vibration transmitted to the member is insulated, and the vibration transmitted from the first member to the second member is insulated by disposing a spring between the first member and the second member. Further, the present invention provides an intermediate table supported by a support mechanism having an actuator and a control device with respect to the floor and having a predetermined negative spring characteristic, and a spring having a predetermined positive spring constant on the intermediate table. And a vibration isolation table. The present invention also provides
A damping device having a predetermined damping rate is provided between the intermediate table and the vibration isolation table in parallel with the spring. Further, the present invention is characterized in that a spring having a predetermined spring constant and a damping device having a predetermined damping rate are provided between the floor and the intermediate table in parallel with the actuator. Further, the present invention is characterized in that the extension of the actuator provided on the floor is increased or decreased according to the increase or decrease of the load acting on the vibration isolation table. Also, in the present invention, the actuator is a voice coil motor, a linear motor,
It is a linear actuator such as a pneumatic actuator or a hydraulic actuator, wherein the control device comprises a displacement sensor, a control circuit, and a power amplifier, and these are used as means for solving the problem.

Hereinafter, embodiments of a vibration isolating method and apparatus according to the present invention will be described with reference to the drawings. According to the present invention, a support mechanism having a positive spring characteristic and a support mechanism having a negative spring characteristic are connected in series, thereby providing a substantially infinite rigidity against a linear motion disturbance generated on the device. At the same time, an embodiment using a magnetic levitation mechanism having zero power characteristics as a support mechanism having negative spring characteristics will be described. FIG. 1 shows a first embodiment of an anti-vibration method and apparatus according to the present invention. In the present invention, a spring 5 is disposed between a floor 6 and a first member 1 as an intermediate base. 6 has a zero power characteristic consisting of a permanent magnet 3 and an electromagnet 4 between the first member 1 and the second member 2 which is a vibration isolation table, while insulating the vibration transmitted from the first member 1 to the first member 1. By providing a floating mechanism, vibration transmitted from the first member 1 to the second member 2 is insulated. In this embodiment, an intermediate table 1 supported by a spring 5 having a predetermined positive spring constant k _P with respect to a floor 6, and a permanent magnet 3 and an electromagnet 4 for the intermediate table 1. And an anti-vibration table 2 supported by a magnetic levitation mechanism having a zero power characteristic of a negative spring constant ks.
Is controlled by an appropriate control device (not shown) so as to increase or decrease the attraction force according to the increase or decrease of the load caused by the increase in the mass of the vibration isolation table 2 provided with the permanent magnet 3. .

As shown in FIG. 2A, the ferromagnetic material 7 may be arranged on the vibration isolation table 2 in combination with the permanent magnet 3 in order to increase the attractive force of the magnet. Alternatively, as shown in FIG. 2B, the permanent magnet 3 may be embedded in the core of the electromagnet 4 to form a composite magnet, and only the ferromagnetic material 7 may be provided on the vibration isolation table 2 side. Further, the arrangement of the electromagnet and the permanent magnet is reversed, that is, the electromagnet 4 is provided on the vibration isolation table 2 side, and the permanent magnet 3 is provided on the intermediate table 1 side, and the attraction force of the electromagnet 4 increases and decreases the load acting on the vibration isolation table 2. May be configured to be increased or decreased according to. Also in this case, FIG.
As shown in (1), the ferromagnetic material 7 may be installed on the intermediate stage 1 side in combination with the permanent magnet 3. Alternatively, as shown in FIG. 2D, the permanent magnet 3 may be embedded in the iron core of the electromagnet 4 to form a composite magnet, and only the ferromagnetic material 7 may be provided on the intermediate stage 1 side.

Next, a zero power magnetic levitation control system employed between the intermediate table and the vibration isolation table according to the present invention will be described with reference to FIGS. The zero-power control is an attractive magnetic levitation system configured by combining an electromagnet and a permanent magnet. As shown in FIG. 3, the weight of the vibration isolation table 12, which is a floating object, is determined only by the attractive force of the permanent magnet 13. The electromagnet 14 on the support fixed side 11 while supporting
This is a control method for constantly maintaining the coil current at zero. In the stationary state of a, the vibration isolation table 12 is stopped at the stationary position in a state in which the forces are balanced, but as shown in the case of the load of b, a constant downward downward external force (mass increase Δm etc.) is applied to the vibration isolation table 12. ) Is applied, an electric current is caused to flow through the coil of the electromagnet 14 to generate an attractive force for raising the vibration isolation table 12, and the attractive force by the permanent magnet 13 and the downward force are controlled so as to be balanced. Thus, at the position where the gap becomes narrow, the current flowing through the electromagnet 14 becomes zero and the electromagnet 14 is brought into a stationary state. Although the control system that performs the above-described operation is omitted in FIG. 1, as shown in FIG. 1D, the position of the vibration isolating table 12, which is the object to be lifted, with respect to the support fixed side (the intermediate table in the apparatus of FIG. 1). Sensor 2 for detecting
1. The anti-vibration table 1 while constantly maintaining the coil current of the electromagnet 14 at zero based on the output signal of the sensor 21.
Control circuit 2 for generating a control signal for holding and floating
2 and a control device 20 including a power amplifier 23 for flowing a predetermined current through the coil of the electromagnet 14 in accordance with the output of the control circuit 22.

FIG. 4 explains a comparison with a normal spring system. As shown on the left side of the drawing, in a normal spring system, the mass m22 supported by a spring having a predetermined positive spring constant increases the mass increase Δm. When this occurs, so-called passive vibration isolation control that moves in the direction of mass increase (load) is performed. On the other hand, in the zero power control, as shown in the right side of the drawing, when the mass increase Δm occurs, the mass m1 is moved in the opposite direction to the spring system.
Electromagnet 1 so that 2 moves upward to narrow the gap
4 is controlled. Therefore, it appears as if it has a negative spring constant. Utilizing the property of the negative spring constant realized by this zero power control, the present invention combines the passive vibration isolation control with the normal positive spring constant to prevent the mass from changing even on the spring. m, that is, the vibration isolation table or the like is configured not to cause displacement.

That is, as shown in FIG.
Constant external force downward due to mass increase Δm etc. in table 2
F₀(= Δmg) adds to the action of zero power control
Therefore, the electromagnet 4 installed on the intermediate table 1 and the vibration isolation table
Is F₀/ K_s(K_sIs zero power
Negative spring constant realized by control). Therefore,
k_s= K_PIs designed to satisfy the following relationship:
If it is, the vibration isolation table will not be displaced at all.
Equation (1) k_c= K₁k_Two/ (K₁+ K _Two)
Explaining that, by zero power control, k₁= -K_TwoWhat
When a negative spring constant that satisfies the relationship_c| = + ∞ (2) The following spring constant is obtained. That is, the magnitude of the spring constant
By combining positive and negative springs
Thus, a spring having an infinite spring constant is obtained. This is a comp
This means that the liance will be zero.

Hereinafter, a theoretical analysis will be performed on the vibration isolation control system of the present invention shown in FIG. <Basic equation> In this analysis, only the displacement of each mass and the floor in the vertical direction is handled. The equation of motion of this system is obtained as follows. _{‥ · · m 1 x 1 =} -k P (x 1 -x 0) -c P (x 1 -x 0) -f c (4) · m 2 x 2 = f c + f d (5) where, x _1, x _2: intermediate scaffold, displacement x from the equilibrium point of the anti-vibration table _0: floor vibration displacement k _P: a spring for supporting the intermediate platform floor spring constant f _c: the operating point of the attractive force of the magnet F _d : Linear motion disturbance acting on the vibration isolation table c _P is a damping coefficient of a damping device, which is not shown in FIG. If there is no damping device, c _P = 0 may be set. The variation of the attraction force of the magnet is approximately expressed as follows. _{f c = k s (x 2} -x 1) + k i i (6) where, k _s: displacement and attraction force coefficient of the magnet k _i: current and attraction force coefficient of the magnet i: Control current

<Zero power control system> Here, the control input is constituted by the relative displacement between the intermediate table and the vibration isolation table. In this case, the control input that achieves zero power control can generally be expressed as: I (s) = − c ₂ (s) s (X ₂ (s) −X ₁ (s)) (7) where c ₂ (s) is a strong proper transfer function having no zero as a pole, It is selected so that the control system is stable. If the dynamics of the intermediate stage can be neglected, stabilization can be achieved by a controller having an order of two or more.

<Analysis of Basic Characteristics> Initial conditions are set for simplicity.
When Laplace transform is performed assuming zero, equations (4) to (7) are obtained.
From the following equation is obtained. X₁(S) = (c)_Ps + k_P) T_Two(S) X₀(S) / t_c(S) + (k_i c_Two(S) sk_s) F_d(S) / t_c(S) (8) X_Two(S) = (c)_Ps + k_P) (K_ic_Two(S) sk_s) X₀(S) / t _c (S) + (m₁s^Two+ (C_P+ K_ic_Two(S)) s + k_P-K_s) F_d(S) / t_c(S) (9) where t₁(S) = m₁s^Two+ C_Ps + k_P (10) t_Two(S) = m_Twos^Two+ K_ic_Two(S) sk_s (11) t_Three(S) = t₁(S) t_Two(S) + m_Twos^Two(K_ic_Two(S) sk_s) (12)

The Laplace transform of each variable is the corresponding uppercase letter.
It is represented by To evaluate stiffness against linear disturbance
, F_d= F₀/ S (F₀: Const) (13) Ignoring the effect of floor vibration (x₀= 0), excluding
Steady displacement x of shake table _Two(∞) asked as follows
It is. x_Two(∞) / F₀= Lim (m₁s^Two− (C_P+ K₁c_Two(S)) s + k_P s → 0 -k_s) / L_c(S) = (k_P-K_s) / K_P(-K_s) = 1 / k_P−1 / k_s (14) Therefore, k_P= K_s If the anti-vibration device is designed to satisfy (15), x_Two(∞) / F₀= 0 (16). This is because compliance is zero,
It means that sex becomes infinite. Also, the displacement of the intermediate table
x₁(∞) and the gap between the electromagnet and the vibration isolation table
Variation (x₁(∞) -x_Two(∞)) is as follows
Is required. x₁(∞) / F₀= 1 / k_P (17) (x₁(∞) -x_Two(∞)) / F₀= 1 / k_s (18) Therefore, a downward force (F₀<0)
When acting, the intermediate platform is displaced downward, while
The swing table can be displaced upward so as to approach the intermediate table.
Was confirmed. Thus, the zero power magnetic levitation mechanism
In a vibration isolator using a mechanical spring, a mechanical spring
Of the spring constant of the magnet and the magnitude of the magnet displacement / attraction force coefficient
By setting, the rigidity against linear motion disturbance is infinite
It was theoretically shown that

FIG. 5 shows a basic experiment apparatus of the vibration isolation method and the apparatus according to the present invention. FIG. 5 (A) is a front view of the experiment apparatus, and FIG. 5 (B) is a side view thereof. An intermediate table 1 is installed via springs 5a, 5b inserted into linear shafts 9a, 9b erected from a base 10 fixed to the floor, and the linear table 9a, 9b is fitted to the intermediate table 1 1
The movement of the intermediate table 1 is restricted by the translational movement of one degree of freedom in the vertical direction by the linear bushes 8a and 8b installed in the first stage. On the other hand, the guide blocks 15a and 15b installed on both lower sides of the vibration isolation table 2 engage with the guide rails 16a and 16b erected on the base 10, and
Is constrained to a single degree of freedom translation in the vertical direction. At the lower end of the vibration isolation table 2, permanent magnets 3
Is installed, and an electromagnet 4 is installed below the opposing intermediate table 1. The sensor 17 detects the relative displacement of the vibration isolation table 2 with respect to the intermediate table 1, and the sensor 18 detects the relative displacement of the intermediate table 1 with respect to the base 10.

Next, referring to FIG. 6 and FIG. 7, an explanation will be given of the results of an experiment performed using the prototype experimental device. FIG. 6 shows the experimental results on the negative spring characteristics of the zero-power magnetic levitation system in the case where the intermediate table 1 is fixed and the mass of the vibration isolation table is increased to 1700 g, 1310 g, and 700 g. Measurements of the table displacement showed that the table displacement increased linearly with any mass, indicating that the zero power control was operating as a linear negative spring. It can also be seen that the spring constant of the zero power control can be set to various values by manipulating the mass of the vibration isolation table.

FIG. 7 shows the results of an experiment on the displacement of the vibration isolation table with respect to the floor when the intermediate table is supported by a spring. The positive spring constant is 6.825 (kN / m), and the positive and negative spring constants are shown. Where the table mass is 1
Based on around 300 g, it can be estimated to be in the range of 1280 g to 1400 g. Incidentally, the negative spring constant at 1310 g is about 7 kN / m. According to the figure, when the table mass is 1380 g, the displacement amount of the vibration isolation table is 20 μm,
It can be seen that a good operation is performed while the table position keeps almost the initial position. This value of 1380 g is within the range estimated before the experiment, and it can also be seen that the operating performance decreases as the difference between the positive and negative spring constants increases.

From these relationships, the validity of the theoretical analysis described above was confirmed. The zero compliance mechanism, which combines the zero power magnetic levitation mechanism and the spring mechanism, makes the displacement of the vibration isolation table with respect to the floor zero, and enables infinite table rigidity against linear motion disturbance. In the actually measured range, the maximum rigidity of the table with respect to the floor is about 490 kN / m. At this time, the displacement of the vibration isolation table with respect to the floor also shows the minimum value. It was confirmed that the compliance could be made almost zero by combining the zero-power magnetic levitation mechanism and the spring, and the rigidity against the linear motion disturbance could be extremely increased.

FIG. 8 shows a second embodiment of the vibration isolating method and apparatus according to the present invention, which is constituted by a permanent magnet 203 and an electromagnet 204 with respect to a support 207 installed on a floor 206. Intermediate table 20 supported by a magnetic levitation mechanism having a zero power characteristic with a negative spring constant K _S
1 and an anti-vibration table 202 supported on the intermediate table 201 by a spring 205 having a predetermined positive spring constant K _{P. In} the illustrated example, the attraction force of the electromagnet 204 provided on the support 207 is permanently set. Intermediate table 2 provided with magnet 203
The electromagnet 204 and the intermediate table 20 are controlled by an appropriate control device (not shown) so as to increase or decrease according to the increase or decrease of the load on the intermediate table 20.
It is configured to control the distance from the device 1.

With such a configuration, the vibration isolation table 2
02, a downward constant external force F ₀ (=
When Δmg) is applied, the spring 205 supporting the vibration isolation table 202 is compressed by F ₀ / K _P and shortened. At the same time, a downward external force F ₀ is also applied to the intermediate table 201 by the reaction force of the spring 205, and the distance between the electromagnet 204 and the intermediate table 201 becomes F ₀ by the action of zero power control.
/ K _S, and the intermediate table 201 is displaced upward by that amount. Therefore, if the anti-vibration device is designed to satisfy the relationship of K _S = K _P , the anti-vibration table 202 will not be displaced at all. This means that the compliance becomes zero, that is, the rigidity becomes infinite. That is, it is understood that the vibration isolation device illustrated in FIG. 8 has the same vibration isolation performance as the vibration isolation device illustrated in FIG.

FIG. 9 shows a third embodiment of the vibration damping method and device according to the present invention. The intermediate table is supported on a floor 300 by a spring 301 having a predetermined positive spring constant K _P and a damping device 302. 303, a magnetic levitation mechanism having a zero power characteristic having a predetermined negative spring constant K _S composed of a permanent magnet 304 and an electromagnet 305 with respect to the intermediate table 303, and a predetermined positive spring constant K _P 'spring 31
1 and the intermediate table 31 supported by the damping device 312
3 and a vibration isolation table 320 supported by a magnetic levitation mechanism having a zero power characteristic having a predetermined negative spring constant K _S ′ and comprising a permanent magnet 314 and an electromagnet 315 with respect to the intermediate table 313. It is composed.

In such a configuration, if the anti-vibration device is designed to satisfy the relations of K _S = K _P and K _S '= K _P ', the left side of the anti-vibration table 320 (the intermediate table 3)
Since the compliance is zero, that is, the rigidity is infinite on the 03 side) and on the right side (the side of the intermediate table 313), the vibration isolation table 320 is completely irrespective of the position on the vibration isolation table 320 where a constant vertical external force acts. No displacement. From such characteristics, when the movable stage 321 is installed on the vibration isolation table 320, the vibration isolation table 320 is not displaced regardless of the position where the moving load 322 is located, and its posture can be kept horizontal.

FIG. 10 shows a vibration damping method and a vibration damping apparatus according to a fourth embodiment of the present invention. A spring 401 and a damping device 402 having a predetermined positive spring constant K _P ¹ are vertically arranged on a floor 400. In the horizontal direction, an intermediate table 405 supported by a spring 403 and a damping device 404 having a predetermined positive spring constant K _P ² , and a permanent magnet 406 and an electromagnet 407 in a vertical direction with respect to the intermediate table 405. A magnetic levitation mechanism having a zero power characteristic having a predetermined negative spring constant K _S ¹ and a permanent magnet 408 and an electromagnet 409 in the horizontal direction.
And is supported by a magnetic levitation mechanism having a zero power characteristic having a predetermined negative spring constant K _S ^2, and a predetermined positive spring constant K in the vertical direction on the floor 400.
A spring 411 and a damping device 412 of _P ³ , an intermediate table 415 supported by a spring 413 and a damping device 414 having a predetermined positive spring constant K _P ^{4 in} the horizontal direction, and the intermediate table 4
15 and the permanent magnet 416 and the electromagnet 4 in the vertical direction.
Magnetic levitation mechanism having a zero power characteristic having a predetermined negative spring constant K _S ³ constructed from 17., the predetermined negative constructed from a permanent magnet 418 and the electromagnet 419 in the horizontal direction spring constant K _S ⁴ And a vibration isolation table 420 supported by a magnetic levitation mechanism having zero power characteristics.

In such a configuration, K _S ¹ =
K _P ¹ , K _S ² = K _P ² , K _S ³ = K _P ³ and K _S ⁴
If the anti-vibration device is designed to satisfy the relationship of = K _P ^4, the left side of the anti-vibration table 420 (the side of the intermediate table 405)
On the right side (on the side of the intermediate table 415), the compliance is zero, that is, the rigidity is infinite, and at the same time, the horizontal compliance on the vibration isolation table 420 is also zero. Even if a constant external force is applied, the vibration isolation table 42
0 is not displaced at all.

Next, referring to FIG. 13 to FIG. 27, a vibration isolation method using a support mechanism including an actuator and a control device as a support mechanism having a negative spring characteristic, a theoretical analysis and an embodiment of the device will be described. Will be described. FIG.
3 includes an intermediate table 1 supported on a floor 6 by a spring 5 having a predetermined positive spring constant, an actuator 25 and a control device 26 for the intermediate table 1, and a predetermined negative And a vibration isolation table 2 supported by a support mechanism having a spring constant. As the actuator 25, a linear actuator such as a voice coil motor, a linear motor, a pneumatic actuator, or a hydraulic actuator is employed. The device 26 includes a displacement sensor 27 for detecting displacement of the vibration isolation table 2 with respect to the intermediate table 1, a control circuit 28, and a power amplifier 29.

FIG. 14 shows a damping device 19 having a predetermined damping rate, which is provided between the floor 6 and the intermediate table 1 in parallel with the spring 5.
Is installed to avoid the resonance of the vibration isolation system and improve the damping characteristics. FIG. 15 shows an arrangement in which a spring 30 having a predetermined spring constant and a damping device 31 having a predetermined damping rate are provided between the intermediate table 1 and the vibration isolation table 2 in parallel with the actuator 25. By supporting the weight of the anti-vibration table 2 at 30, the energy consumption of the actuator 25 can be reduced, and furthermore the resonance of the anti-vibration system can be avoided to improve the damping characteristics. The one shown in FIG. 16 is a combination of those shown in FIGS. 14 and 15. That is, a damping device 19 having a predetermined damping rate is installed between the floor 6 and the intermediate table 1 in parallel with the spring 5, and an actuator 25 is installed between the intermediate table 1 and the vibration isolation table 2. A spring 30 having a predetermined spring constant and a damping device 31 having a predetermined damping rate.

The negative spring characteristic will be described with reference to FIGS. <Normal Spring Characteristics (Positive Spring Characteristics)> As shown in FIG. 17A, on a table 24 having a mass m supported by an ordinary spring having a predetermined positive spring constant (k),
If a new mass Δm is generated as shown in FIG. 17B and a downward external force Δm is applied, the spring contracts by Δmg / k, and the table 24 is displaced by Δmg / k in the same direction as the external force, and 6 is L-Δmg / k. <Negative Spring Characteristics> In FIG. 18A, the gravity mg acting on the table 24 having the mass m and the force generated in the actuator 25 are in a balanced state, and the distance between the floor 6 and the mass m is L.
Is kept in As shown in FIG. 18B, when a new mass increase Δm occurs on the table 24 and a downward external force Δmg is applied, the actuator 25 extends and the distance of the mass m from the floor 6 increases to L + ΔL. It is assumed that it has the characteristic of: At this time, the table 24 is displaced by ΔL in a direction opposite to the external force. This system can be said to have negative spring properties. The magnitude k _s of the negative spring constant is k _s = Δ
It is given in mg / ΔL.

The one shown in FIG. 19 corresponds to FIG. 15 and FIG.
6 shows a behavior when a system in which a spring 30 and a damping device 31 are provided in parallel with the actuator 25 has a negative spring characteristic like the vibration isolator shown in FIG. 6, and FIG. It is assumed that the gravity mg acting on the table 24, the force generated in the actuator 25, and the spring force of the spring 30 are in a balanced state, and the distance between the floor 6 and the mass m is kept at L. As shown in FIG.
4, a new mass increase Δm is generated and a downward external force Δmg
Is applied, the actuator 25 extends, and the distance from the floor 6 of the table 24 of the mass m increases to L + ΔL. At this time, as in the case shown in FIG. 18, since the table 24 is displaced by ΔL in the direction opposite to the external force, it can be said that this system has a negative spring characteristic. It is given by the magnitude of the negative spring constant k _s = Δmg / ΔL.

<Response to Linear Motion Disturbance of Vibration Isolator> Here, the response of the vibration isolator to linear motion disturbance shown in FIG. 13 will be described with reference to FIG. If a constant downward force F ₀ (= Δmg) is applied to the vibration isolation table 2 due to a mass increase Δm or the like, a negative spring characteristic is realized, and the distance between the vibration isolation table 2 and the intermediate table 1 is Δmg / k _S only to increase. On the other hand, for the spring 5, its spring constant is k ₁
Then, since it shrinks by Δmg / k ₁ , the intermediate table 1 and the floor 6
Decreases by Δmg / k ₁ . Therefore, k
If vibration isolation device is designed to meet the _S = k ₁ the relationship, anti-vibration table 2 would not at all displaced.
That is, by connecting in series a positive spring and a negative spring having the same spring constant, a spring having an infinite spring constant is realized.

<First Control Method for Realizing Negative Spring Characteristics> A method for realizing negative spring characteristics in the system shown in FIG. 19 will be described with reference to FIG. A control device 28 including a displacement sensor 27, a control circuit 28, and a power amplifier 29 is added to the system shown in FIG. These elements are shown in FIG.
3 to 16 correspond to the displacement sensor 27, the control circuit 28, and the power amplifier 29. The control circuit 28 has the following mechanism. The external force estimating mechanism 28A estimates the external force f _d (corresponding to −Δmg in the example shown in FIG. 19 ₎ acting on the table 24 based on the information of the displacement sensor 27. When the estimated value is expressed as f ＾ _d , the target displacement generation mechanism 2
In step 8B, based on the output from the external force estimating mechanism 28A, a target displacement determined from the realized negative spring characteristic is calculated. Assuming that the magnitude of the negative spring constant to be set is k _S , the target displacement x _ref can be obtained from the following equation. x _ref = −f ＾ _d / k _S (19) where the sign of the displacement is positive when the direction is the same as the direction of the external force. The position control mechanism 28C controls the displacement of the table 24 so as to match the target displacement. Specifically, a control signal for expanding and contracting the actuator 25 by the target displacement calculated by Expression 19 is generated and output to the power amplifier circuit 29. The power amplifier circuit 29 drives the actuator 25 according to the control signal.

<Theoretical analysis> Here, the actuator 2
The case where a voice coil motor is used as 5 will be described. In the case where another actuator is used, a negative spring characteristic can be realized in the same manner. FIG. 22 shows a mechanical model.
The equation of motion of this system is obtained as follows. _{‥ · m 2 x + c a} x + k a x = f a + f d, where (20), m _2: mass of the table 24 x: displacement from the equilibrium point of the table 24 k _a: spring 30 inserted in parallel with the actuator 25
The spring constant c _a: damping coefficient of the actuator 25 and the inserted damping device in parallel 31 f _a: force generated by the actuator 25 f _d: force generated in the linear disturbance actuator 25 acting on the table 24, the coil current Since it is proportional, it is expressed as follows. f _a = ki _{i ,} (21) where _ki : thrust constant of voice coil motor i: control current

By substituting equation (21) into equation (20), the following equation is obtained. ‥ · m ₂ x + c _ax + k _ax = ki _i + f _d , (22) When designing a control system, it is assumed that the linear disturbance f _d is constant. F _d = 0 (23) When the expressions (22) and (23) are collectively expressed in a state space, the following expression is obtained. X (t) = Ax (t) + Bu (t) (24) where:

(Equation 1) u = i, a ₀ = k _a / m ₂ , a ₁ = c _a / m ₂ , b ₀ =
by applying the _{k i / m 2, d 0} = 1 / m 2 observer theory, the displacement x of the table 24 is detected by the sensor 27, it is possible to estimate the external force acting on the table 24.

When the same-dimensional observer is used, the dynamic characteristic of the observer is expressed by the following equation. X ＾ = (A−EC) x ＾ (t) + Bu (t) + ECx (t) (25) where

(Equation 2) The matrix E is a matrix called an observer gain, and a procedure for determining the matrix E will be described below. Actual state vector x
An error vector e (t) = (t) −x ＾ (t) (26) between (t) and its estimated value x ＾ (t) satisfies the following equation. E (t) = (A-EC) e (t) (27) Therefore, if all the eigenvalues of the matrix (A-EC) have a negative real part, limx ＾ (t) = x (t) (28) ) T → ∞.

The eigenvalues of the matrix (A-EC) are called observer poles, which are characteristic polynomials of the matrix (A-EC) det [sI- (A-EC)] = s ³ + (a ₁ + e ₁ ). s ² + (a ₀ + a ₁ e ₁ + e ₂ ) s + d ₀ e ₃ (29) Here, the observer gain E is determined so that the poles of the observer are as follows: Λ = ｛− λ _1, −λ ₂ , −λ ₃ ｝ (30). Here, it is assumed that λ ₁ is selected so as to satisfy Re [λ ₁ ]> 0 (i = 1, 2, 3) (31). The characteristic polynomial determined by the pole to be arranged is obtained as in the following equation. t _d (s) = (s + λ ₁ ) (s + λ ₂ ) (s + λ ₃ ) = s ³ + (λ ₁ + λ ₂ + λ ₃ ) s ² + (λ ₁ λ ₂ + λ ₂ λ ₃ + λ ₃ λ ₁ ) s + λ ₁ λ ₂ λ ₃ (32) By comparing Equation (29) and Equation (32), the gain E of the observer is determined as follows. e ₁ = λ ₁ + λ ₂ + λ ₃ -a ₁ (33) e ₂ = λ ₁ λ ₂ + λ ₂ λ ₃ + λ ₃ λ ₁ -a ₀ -a ₁ e ₁ (34) e ₃ = λ ₁ λ ₂ λ ₃ / D ₀ (35)

When the gain E of the observer is determined as described above, if f ＾ _d is an estimated value of f _d , the following equation is established. _{f ^ d = f d + c} 1 exp (-λ 1 t) + c 2 exp (-λ 2 t) + c 3 exp (-λ 3 t) (36) _{where, c 1, c 2, c} 3 is the control object And a constant determined from the initial conditions of the observer. From the condition of Expression 31, limf ＾ _d (t) = f _d (37) t → ∞ holds. Assuming that the magnitude of the negative spring constant to be set is k _s , the target displacement x _ref can be obtained from the following equation. _{x ref = -f ^ d / k} s (38) where, f ^ _d is an estimate of f _d as determined by the observer (25). I-PD control is applied to position control. That is, the control input is determined as in the following equation. _{· U (t) = p I} ∫ (x ref -x) dt-p d x (t) -p V x (t) (39)

Substituting equation (35) into equation (21),
By rearranging the transformed equations, the following equation is obtained. X (s) = (b₀p_I/ (S^Three+ (B₀p_V+ A₁) S^Two+ (B₀p_d+ A ₀ ) S + b₀p_I)) X_ref(S) + (sd₀/ (S^Three+ (B₀p_V+ A₁) S ^Two + (B₀p_d+ A₀) S + b₀p_I)) F_d(S) (40) where the Laplace-transformed variable is the corresponding uppercase letter
Is shown. Feedback gain p_I, P_d, P_VBut
When the poles of the closed loop system are selected to be stable,
From equations (36) and (40), f that satisfies equation (23)_dTo
And limx (t) =-f_d/ K_s (41) t → ∞ is established. Therefore, the magnitude k of the spring constant_sNegative
Spring characteristics are realized.

<Second Control Method for Achieving Negative Spring Characteristics> Here, a method of directly configuring a control input for achieving negative spring characteristics without explicitly using an observer or a position control system will be described. For the derivation on the control side, a transfer function expression method is used. When Laplace transform is performed with the initial condition set to zero for simplicity, the following equation is obtained from equations (20) and (21). _{X (s) = (b 0} I (s) + d 0 F d (s)) / (s 2 + a 1 s + a 0) (42) control input i (t) (I (s )) , the signal of the displacement sensor When performing linear control of a time-invariant gain, the control law can be generally expressed as the following equation. I (s) =-p (s) X (s) (43) When a controller having a proper transfer function is used as a controller, it can be generally expressed as the following equation. p (s) = h (s ) / g (s) = (h n s n + h n-1 s n-1 + ··· + h 1 s + h 0) / (s n + g n-1 s n-1 + .. + G ₁ s + g ₀ ) (44) When a controller having a strictly proper transfer function is used, h _n = 0 (45).

Substituting equation (43) into equation (42) and rearranging
Then, the following equation is obtained. X (s) = (g (s) / ((s^Two+ A₁s + a₀) G (s) + b₀h (s))) d₀F_d(S) (46) To evaluate the rigidity against the linear motion disturbance, F_d(S) = F₀/ S (F₀Is constant.) (47) A control law is selected so that the closed-loop system is stable.
If this is the case, the steady displacement x (∞) can be obtained as follows. x_Two(∞) / F₀= Lim ((g (s) / ((s^Two+ A₁s + a₀) G (st → 0) + b₀h (s))) d₀= D₀g₀/ (A₀g₀+ B₀h₀(48) From equation (48), this system has a size k_sNegative spring stiffness
In order to have g
It can be seen that (s) and h (s) should be selected. d₀g₀/ (A₀g₀+ B₀h₀) =-1 / k_s (49) ∴k_a+ K_ih₀/ G₀= -K_s (50) When using a controller with a proper transfer function,
Equation (49) must be satisfied and the closed-loop system must be stable.
For this purpose, it is necessary to have an order of n = 2 or more. Reverse
If this condition is satisfied, the poles of the closed loop
Can be arranged. When n = 2, from equation (46)
Characteristic polynomial t of closed loop system_c(S) is calculated as follows:
Can be t_c(S) = s^Four+ (A₁+ G₁) S^Three+ (A₀+ G₀+ A₁g₁+ B₀h _Two ) S^Two+ (A₀g₁+ A₁g₀+ B₀h₁) S + (a₀g₀+ B₀h₀) (51)

It is assumed that a characteristic polynomial determined by the pole to be arranged is given by the following equation. t _d (s) = s ⁴ + c ₃ s ³ + c ₂ s ² + c ₁ s + c ₀ (52) From the equations (50), (51) and (52), it is desirable to have a negative spring stiffness of the set magnitude. The coefficient of the controller that realizes the closed-loop system having the pole is obtained as follows. _{g 0 = -c 0 / d 0} k s = -c 0 m / k s (53) g 1 = c 3 -a 1 (54) h 0 = (c 0 -a 0 g 0) / b 0 (55 _{) h 1 = (c 1 -a} 0 g 1 -a 1 g 0) / b 0 (56) h 2 = (c 2 -a 0 -g 0 -a 1 g 1) / b 0 (57) strictly When a controller having a proper transfer function is used, a controller having three or more orders is required in order to satisfy Expression (50) and arbitrarily arrange the poles of the closed loop system. in the case of n = 3, the characteristic polynomial determined from placement want electrode, when _{~ t d (s) = s} 5 + c 4 s 4 + c 3 s 3 + c 2 s 2 + c 1 s + c 0 (58), the coefficients of the controller It is required as follows. _{g 0 = -c 0 / d 0} k n = -c 0 m / k s (59) g 2 = c 4 -a 1 (60) g 1 = c 3 -a 0 -a 1 g 2 (61) h _{0 = c 0 (a 0 /} d 0 k s +1) / b 0 = c 0 (k / k s +1) / b 0 (62) h 1 = (c 1 -a 0 g 1 -a 1 g 0) / B ₀ (63) h ₂ = (c ₂ −a ₀ g ₂ −a ₁ g ₁ −g ₀ ) / b ₀ (64)

<Operation Analysis of Anti-Vibration Apparatus> A theoretical analysis is performed on the anti-vibration apparatus shown in FIG. FIG. 23 shows the dynamic model. It is assumed that a voice coil motor is used as the actuator, as in the above-described theoretical analysis on the control method for realizing the negative spring characteristic. <Basic equation> Each mass 1, 2 and floor 6 in FIG.
Shall translate in the vertical direction. The equation of motion of this system is obtained as follows. _{‥ · · m 1 x 1 =} -k 1 (x 1 -x 0) -c 1 (x 1 -x 0) -k a (x 1 -x 2 · ·) -c a (x 1 -x 2) _{-f a (65) ‥ · ·} m 2 x 2 = -k a (x 2 -x 1) -c a (x 2 -x 1) + f a + f d (66) where, x _1: intermediate scaffold 1 displacement x ₂ from the equilibrium point of: anti-vibration displacement x from the equilibrium point of the table 2 _0: vibration displacement k ₁ floor 6: spring constant of the spring 5 c _1: damping coefficient of the damping device 19 k _a: actuator 25 and hotel is a spring constant of the spring 30 c _a: damping coefficient of the actuator 25 and the hotel is a damping device 31 f _d: vibration-linear disturbances acting on the table 2 f _a: thrust actuator of the actuator 25 (voice coil motor) occurs The force exerted is proportional to the coil current and is expressed as follows. f _a = ki _i (67) where _ki : thrust constant of the voice coil motor i: control current

<Control System for Realizing Negative Stiffness (Control Method)
2)> The second control method is applied here. Middle
The control input is composed of the relative displacement of the table and the vibration isolation table.
Then, the control input can be generally expressed as
it can. I (s) = − p (s) (X_Two(S) -X₁(S)) = ((h_nsⁿ+ H_n-1 s^n-1+ ... + h₁s + h₀) / (Sⁿ+ G_n-1s^n-1+ ... + g₁s + g ₀ )) (X_Two(S) -X₁(S)) (68) where p (s) stabilizes the closed loop system and
(See equation (50)).
See). k₀+ K_ih₀/ G₀= -K_s (69) If the dynamic of the intermediate stage 1 can be ignored, n = 2
Using a controller with the above order stabilizes the closed loop
At the same time, it is possible to satisfy equation (69).
Wear.

<Analysis of Basic Characteristics> For simplicity, the Laplace transform is performed assuming that the initial condition is zero.
From 8), the following equation is obtained. _{X 1 (s) = (c} 1 s + k 1) (m 2 s 2 + c a s + k a + k i p (s)) X 0 (s) / t c (s) + (c a s + k a + k i p (s _{)) F d (s) /} t c (s) (70) X 2 (s) = (c 1 s + k 1) (c a s + k a + k i p (s)) X 0 (s) / t c (s ^{_{) + (m 1 s 2 +}} c 1 s + k 1 + c a s + k a + k i p (s)) F d (s) / t c (s) (71) _{where, t c (s) = (} m 1 s 2 _{+ c 1 s + k 1)} (m 2 s 2 + c a s + k a + k i p (s)) + m 2 s 2 (c a s + k a + k i p (s)) (72)

In order to evaluate the rigidity against a linear motion disturbance, it is assumed that F _d = F ₀ / s (F ₀ : constant) (73) If the effect of the vibration of the floor 6 is ignored (x ₀ = 0),
The steady displacement x ₂ (∞) of the vibration isolation table 2 is obtained as follows. _{x 2 (∞) / F 0} = lim (m 1 s 2 + c 1 s + k 1 + c a s + k a + k i t → 0 p (s)) / t c (s) = (k 1 + k a + k i h 0 / _{g 0) / k 1 (k} a + k i h 0 / g 0) (74) equation (69) from _{x 2 (∞) / F 0} = - (k 1 -k s) / k 1 k s (75) Therefore, if the anti-vibration device is designed to satisfy k ₁ = k _s (76), then x ₂ (∞) / F ₀ = 0 (77). This means that the compliance is zero, ie the stiffness is infinite. In the above analysis, if c ₁ = 0, k _a = 0, and c _a = 0, FIG.
The analysis result of the vibration isolation device indicated by is obtained, and k _a =
0, putting a c _a = 0, the analysis results on anti-vibration apparatus shown in FIG. 14 is obtained by placing a c ₁ = 0, the analysis results on anti-vibration apparatus shown in FIG. 15 is obtained immediately.

FIG. 24 shows a basic experiment apparatus of the vibration isolation method and the vibration isolation method according to the present invention.
A voice coil motor 104 is mounted on an intermediate base 103 connected to the base 100 via the bases 1 and 102. The movement of the intermediate table 103 is performed by the parallel leaf spring 101,
102 constrains the translation to one degree of freedom in the vertical direction. On the other hand, an anti-vibration table 106 is attached to the movable portion 105 of the voice coil motor, and the voice coil motor is driven by the voice coil motor to perform a vertical translational motion.
The relative displacement of the vibration isolation table 106 with respect to the intermediate table 103 is detected by the sensor 107 and the intermediate table 1 with respect to the base 100 is detected.
03 is configured to be detected by the sensor 108.

Next, with reference to FIG. 25 and FIG. 26, the results of an experiment performed using the prototype basic experiment apparatus will be described. FIG. 25 shows experimental results on negative spring characteristics realized using the second control method for realizing negative spring characteristics (paragraphs 0039 to 0041). (A) 15k
N / m, (b) 20 kN / m, and (c) 25 kN / m, and the table displacement was measured when the additional mass Δm to the table was increased. In the figure, the vertical axis represents the load due to the additional mass Δm (= Δmg).
[N], and the horizontal axis represents the upward displacement [mm] of the table. From FIG. 25, it was found that in any of the cases (a) to (c), the table displacement increased linearly, and a negative spring characteristic was realized. Also, the magnitude of the actually measured negative spring constant is (a) 14.9 kN / m,
(B) was 19.7 kN / m, and (c) was 25.1 kN / m, which was almost the same as the set value when the control system was designed. From this result, the size of the negative spring constant is also seen that it is possible to freely set the value of k ₃ is set to festival to design the control system.

FIG. 26 shows the results of experiments on the displacement of the vibration isolation table with respect to the base and the displacement of the intermediate table with respect to the base when the intermediate table is supported by the parallel leaf springs. The value of the positive spring constant by the parallel leaf spring is 16.4 kN
/ M, the magnitude of the negative spring constant set at the festival for designing the control system is also set to 16.4 kN / m. From the figure, it can be seen that when the load on the table is increased, the intermediate table descends linearly, while the table is hardly displaced. When the load on the table is 5N, the amount of displacement of the table is about 5 μm, and the rigidity with respect to the base is about 1000 kN / m, which is about 61 times the magnitude of the positive spring constant or the set negative spring constant. I have.

From these relationships, the validity of the theoretical analysis described above was confirmed. The zero compliance mechanism, which combines a support mechanism with a negative spring characteristic and a spring mechanism composed of a voice coil motor (actuator) and a control device, theoretically reduces the displacement of the vibration isolation table relative to the base (floor) to zero. In addition, it is possible to have infinite rigidity against a linear motion disturbance. Within the measured range, the rigidity of the table relative to the base (floor) is about 1000 kN / m.
In this case, the displacement of the vibration isolation table with respect to the floor is 5 μm with respect to a 5N linear motion disturbance. This is because the compliance can be made almost zero by combining a spring mechanism with a support mechanism having a negative spring characteristic composed of a voice coil motor (actuator) and a control device. It was confirmed that the rigidity could be extremely increased.

FIGS. 27 to 30 show another embodiment.
The basic structure is the same as that shown in FIGS. 13 to 16, except that the spring 5 or the spring 5 and the damping device are provided between the intermediate table 1 and the floor 6 as shown in FIGS. 19
And the actuator 25, or the actuator 25, the spring 30, and the damping device 31 are disposed between the intermediate table 1 and the vibration isolation table 2,
27 to 30 employ a mode in which a mechanism for supporting the intermediate table 1 and a mechanism for supporting the vibration isolation table 2 are exchanged. In other words, in the configuration shown in FIGS. 27 to 30, a negative spring characteristic composed of an actuator and a control device is provided between the floor 6 and the intermediate base 1 to insulate vibration transmitted from the floor to the intermediate base 1. It is configured as follows. With this configuration, the displacement sensor 2
7. The floor 6 on which the control of the control device 26 comprising the control circuit 28, the power amplifier 29 and the actuator 25 is on the stationary side.
In this case, routing of wiring and the like can be simplified.

The embodiments of the vibration-damping method and the vibration-damping device according to the present invention have been described above. However, within the scope of the present invention, the shapes and types of the intermediate table and the vibration-isolating table, and the shapes of the electromagnet and the permanent magnet , Type and arrangement thereof (Electromagnet is installed on the intermediate table or vibration isolation table, permanent magnet is installed on the vibration isolation table or intermediate table, ferromagnetic material is provided in addition to permanent magnet, or Permanent magnets may be incorporated in the core of the electromagnet and installed on only one of the vibration isolation table and the intermediate table, and the other may be installed with a ferromagnetic material), actuators, springs and damping devices , Type and arrangement on the intermediate table (an appropriate damping device may be provided in addition to the spring between the floor and the intermediate table), zero power control means, actuator control means ( The type of the position sensor, the type of the control circuit, the power amplification mode and the control mode of the actuator using them, and the direction of vibration isolation (in each of the above-described embodiments, mainly the vertical vibration isolation has been described. It is needless to say that the vibration or the vibration in the vertical direction and the horizontal direction can be simultaneously eliminated.

[0052]

As described above in detail, according to the present invention, a support mechanism having a positive spring characteristic and a support mechanism having a negative spring characteristic are connected in series to generate on a device. By providing almost infinite rigidity against linear motion disturbances and isolating vibration to the floor, devices such as anti-vibration tables can support the floor with a support mechanism having a positive spring characteristic and a negative spring characteristic. Since it is arranged via a supporting mechanism having a high rigidity against linear motion disturbance generated on the device without deteriorating the vibration insulation performance against ground motion disturbance from the floor, it exhibits a high vibration isolation function. To enable precision machining.

Further, a spring is provided between the floor and the first member to insulate vibration transmitted from the floor to the first member, and a permanent magnet and an electromagnet are provided between the first member and the second member. By providing a magnetic levitation mechanism having a zero power characteristic composed of a magnetic force levitation mechanism, the vibration transmitted from the first member to the second member is insulated by only the magnetic force control which is relatively easy to control, and High rigidity against linear motion disturbances is maintained without impairing vibration insulation performance against ground motion disturbances.
Demonstrates high vibration isolation function and enables precision machining.

Further, a spring is provided between the floor and the first member to insulate vibration transmitted from the floor to the first member, and between the first member and the second member by an actuator and a control device. By imparting the following negative spring characteristics, the vibration transmitted from the first member to the second member is insulated, thereby isolating the vibration transmitted from the first member to the second member, and isolating the vibration. Of course, it is necessary to ensure high rigidity against linear motion disturbances without deteriorating the vibration insulation performance of the table against ground motion disturbances, and demonstrate high vibration isolation function to enable precision machining, etc. Therefore, various actuators can be employed to achieve the above, and the degree of freedom in design is improved.

In the case where a damping device having a predetermined damping rate is installed between the floor and the intermediate table in parallel with the spring,
It is possible to suppress the occurrence of resonance and exhibit a higher vibration isolation function as a whole. Furthermore, when the attraction force of the electromagnet provided on the intermediate table is increased or decreased in accordance with the increase or decrease of the load acting on the vibration isolation table provided with the permanent magnet, or the actuator provided on the intermediate table When the elongation is increased or decreased in accordance with the increase or decrease of the load acting on the vibration isolation table, wiring to the vibration isolation table can be avoided, so that the control equipment is simplified.

Further, the attractive force of the composite magnet composed of the electromagnet and the permanent magnet provided on the intermediate table with respect to the vibration removing table provided with the ferromagnetic material is changed according to the increase and decrease of the load acting on the vibration removing table. In the case of increasing or decreasing, it is possible to avoid wiring to the vibration isolation table, and at the same time, it becomes easy to manufacture a vibration isolation table in which only the ferromagnetic material is installed. Furthermore, when the electromagnet provided on the vibration isolation table is configured to increase or decrease the attraction force to the intermediate table provided with the permanent magnet in accordance with the increase or decrease of the load acting on the vibration isolation table, only the permanent magnet is used. Can be simplified in the configuration of the intermediate table where the is installed. Also, the attractive force of the composite magnet composed of the electromagnet and the permanent magnet provided on the vibration isolation table to the intermediate table provided with the ferromagnetic material may be increased or decreased according to the increase or decrease of the load acting on the vibration isolation table. In this case, it is easy to manufacture an intermediate table on which only the ferromagnetic material is installed.

When a magnetic levitation mechanism having a zero power characteristic is provided between the floor and the first member, or a support having a predetermined negative spring characteristic is constituted by an actuator and a control device for the floor. In the case of being constituted by an intermediate table supported by a mechanism, and a vibration isolation table supported by a spring having a predetermined positive spring constant in the intermediate table,
Since the magnetic force control of the magnetic levitation mechanism or the control of the actuator can be performed between the magnetic levitation mechanism and the floor on the stationary side, routing of wiring and the like is simplified. Further, when a spring having a predetermined spring constant and a damping device having a predetermined damping rate are installed between the intermediate table and the vibration isolation table in parallel with the actuator, the weight of the vibration isolation table is supported by the spring. As a result, the energy consumption of the actuator can be reduced, and the resonance of the vibration isolation system can be avoided to improve the damping characteristics.
Thus, according to the present invention, without damaging the vibration isolation performance against ground motion disturbances, a high rigidity against linear motion disturbances is ensured, a high vibration isolation function is exhibited, and a precision processing or the like is enabled, and the vibration isolation method. An apparatus is provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a first embodiment using a magnetic levitation mechanism having a zero power characteristic of a vibration isolation method and a vibration isolation device according to the present invention.

FIG. 2 is a diagram showing a modification of the first embodiment.

FIG. 3 is an explanatory diagram of features of a zero power control system used in the present invention.

FIG. 4 is an operation comparison diagram of a spring system and a zero power control system.

FIG. 5 is a view showing a basic experiment apparatus of the vibration isolation method and the apparatus according to the present invention.

FIG. 6 is an experimental result diagram of a negative spring characteristic of a zero power magnetic levitation system.

FIG. 7 is an experimental result diagram of displacement of a vibration isolation table with respect to a floor.

FIG. 8 is an explanatory view showing a second embodiment of the vibration isolation method and the vibration isolation device according to the present invention.

FIG. 9 is an explanatory view showing a third embodiment of the vibration isolation method and the vibration isolation device according to the present invention.

FIG. 10 is an explanatory view showing a fourth embodiment of the vibration isolation method and the vibration isolation device according to the present invention.

FIG. 11 is a diagram of a conventional vibration isolation system for a spring system.

FIG. 12 is an explanatory diagram of a conventional active vibration isolation device.

FIG. 13 is an explanatory view showing a fifth embodiment using a support mechanism having a negative spring characteristic using an actuator and a control device of the vibration isolation method and the device of the invention.

FIG. 14 is an explanatory diagram showing a sixth embodiment of the vibration isolation method and the vibration isolation device according to the present invention.

FIG. 15 is an explanatory diagram showing a seventh embodiment of the vibration isolation method and the device therefor according to the present invention.

FIG. 16 is an explanatory view showing an eighth embodiment of the vibration isolation method and the device therefor according to the present invention.

FIG. 17 is an explanatory diagram of a positive spring characteristic.

FIG. 18 is an explanatory diagram of a negative spring characteristic.

FIG. 19 is a negative spring characteristic behavior diagram by an actuator provided with a spring and a damping device.

FIG. 20 is a response diagram of the vibration isolation device to a linear motion disturbance.

FIG. 21 is an explanatory diagram of a control method for realizing negative spring characteristics using an actuator.

FIG. 22 is a mechanical model diagram using a voice coil motor as an actuator.

FIG. 23 is a mechanical model diagram of the vibration isolator of FIG.

FIG. 24 is a basic experimental apparatus diagram of a support mechanism having negative spring characteristics.

FIG. 25 is a diagram showing the relationship between the load and the displacement of the table.

FIG. 26 is a displacement diagram of a table and an intermediate table.

FIG. 27 is an explanatory diagram showing a ninth embodiment of the vibration isolation method and the device thereof according to the present invention.

FIG. 28 is an explanatory view showing a vibration-damping method and a vibration-damping device according to a tenth embodiment of the present invention.

FIG. 29 is an explanatory diagram showing an eleventh embodiment of the vibration isolation method and the device therefor according to the present invention.

FIG. 30 is an explanatory view showing a twelfth embodiment of the vibration isolation method and the vibration isolation device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intermediate table (1st member) 2 Vibration isolation table (2nd member) 3 Permanent magnet 4 Electromagnet 5 Spring 6 Floor 7 Ferromagnetic material 19 Damping device 25 Actuator 26 Control device 27 Displacement sensor 28 Control circuit 29 Power amplifier 30 Spring 31 Damping device

Claims (26)

[Claims] 1. By connecting a support mechanism having a positive spring characteristic and a support mechanism having a negative spring characteristic in series, it has a substantially infinite rigidity against a linear motion disturbance generated on the apparatus. A vibration isolation method characterized by insulating the floor against vibrations. 2. A spring is provided between the floor and the first member to insulate vibration transmitted from the floor to the first member, and a permanent magnet and an electromagnet are provided between the first member and the second member. A vibration isolation method characterized by disposing a magnetic levitation mechanism having zero power characteristics composed of: (a) to isolate vibration transmitted from the first member to the second member. 3. An intermediate table supported on a floor by a spring having a predetermined positive spring constant, and a permanent magnet and an electromagnet for the intermediate table to provide a zero power characteristic of a predetermined negative spring constant. And a vibration isolation table supported by a magnetic levitation mechanism. 4. An anti-vibration device according to claim 3, wherein a damping device having a predetermined damping rate is provided between said floor and said intermediate table in parallel with said spring. 5. The apparatus according to claim 3, wherein the attraction force of the electromagnet provided on the intermediate table is increased or decreased according to an increase or decrease of a load acting on a vibration isolation table provided with a permanent magnet. 5. The vibration isolator according to 4. 6. The attraction force of a composite magnet comprising an electromagnet and a permanent magnet provided on the intermediate table to a vibration isolation table provided with a ferromagnetic material according to an increase or decrease of a load acting on the vibration isolation table. The anti-vibration device according to claim 3, wherein the anti-vibration device is configured to increase or decrease. 7. The apparatus according to claim 1, wherein an attraction force of an electromagnet provided on the vibration isolation table to an intermediate table provided with a permanent magnet is increased or decreased in accordance with an increase or decrease of a load acting on the vibration isolation table. The anti-vibration device according to claim 3 or 4, wherein 8. The attraction force of the composite magnet composed of the electromagnet and the permanent magnet provided on the vibration isolation table to the intermediate table provided with the ferromagnetic material according to the increase and decrease of the load acting on the vibration isolation table. The anti-vibration device according to claim 3, wherein the anti-vibration device is configured to increase or decrease. 9. A magnetic levitation mechanism having zero power characteristics comprising a permanent magnet and an electromagnet is disposed between the floor and the first member to insulate vibration transmitted from the floor to the first member, and A vibration isolation method, comprising: arranging a spring between a first member and a second member to insulate vibration transmitted from the first member to the second member. 10. An intermediate table composed of a permanent magnet and an electromagnet with respect to the floor and supported by a magnetic levitation mechanism having a zero power characteristic with a predetermined negative spring constant, and a predetermined positive spring mounted on the intermediate table. A vibration isolation table supported by a spring having a constant. 11. Between the intermediate table and the vibration isolation table,
The vibration damping device according to claim 10, wherein a damping device having a predetermined damping rate is provided in parallel with the spring. 12. The apparatus according to claim 1, wherein an attraction force of the electromagnet provided on the floor side to an intermediate table provided with a permanent magnet is increased or decreased in accordance with an increase or decrease of a load acting on the intermediate table. Item 12. The vibration isolation device according to item 10 or 11. 13. A composite magnet composed of an electromagnet and a permanent magnet installed on the floor side, in which an attractive force acting on an intermediate table provided with a ferromagnetic material is increased or decreased according to a load applied to the intermediate table. The anti-vibration device according to claim 10, wherein the anti-vibration device is configured to increase or decrease. 14. The apparatus according to claim 1, wherein the attraction force of the electromagnet provided on the intermediate table with respect to the permanent magnet installed on the floor is increased or decreased in accordance with the increase or decrease of the load acting on the intermediate table. Item 12. The vibration isolation device according to item 10 or 11. 15. A composite magnet comprising an electromagnet and a permanent magnet provided on the intermediate table, the attraction force acting on the ferromagnetic material installed on the floor side being increased or decreased according to the increase or decrease of the load acting on the intermediate table. The anti-vibration device according to claim 10, wherein the anti-vibration device is configured to increase or decrease. 16. A spring is disposed between the floor and the first member to insulate vibration transmitted from the floor to the first member, and between the first member and the second member from the actuator and the control device. A vibration isolation method, wherein a vibration transmitted from the first member to the second member is insulated by imparting a negative spring characteristic by a supporting mechanism having the structure. 17. An intermediate table supported on a floor by a spring having a predetermined positive spring constant, and an intermediate table supported by a supporting mechanism having an actuator and a control device and having a predetermined negative spring constant. And a vibration isolation table. 18. The vibration damping device according to claim 17, wherein a damping device having a predetermined damping rate is provided between the floor and the intermediate table in parallel with the spring. 19. Between the intermediate table and the vibration isolation table,
19. The vibration damping device according to claim 17, wherein a spring having a predetermined spring constant and a damping device having a predetermined damping rate are installed in parallel with the actuator. 20. The apparatus according to claim 17, wherein the extension of the actuator provided on the intermediate table is increased or decreased in accordance with the increase or decrease of the load acting on the vibration isolation table.
Or the vibration isolator according to 18. 21. A support mechanism comprising an actuator and a control device between the floor and the first member imparts a negative spring characteristic to insulate vibration transmitted from the floor to the first member, and to provide the first member with a negative spring characteristic. A vibration isolation method characterized by insulating a vibration transmitted from the first member to the second member by disposing a spring between the first member and the second member. 22. An intermediate base supported by a support mechanism having an actuator and a control device with respect to the floor and having a predetermined negative spring characteristic, and supported by a spring having a predetermined positive spring constant on the intermediate base. And a vibration isolation table. 23. Between the intermediate table and the vibration isolation table,
23. The vibration damping device according to claim 22, wherein a damping device having a predetermined damping rate is installed in parallel with the spring. 24. The apparatus according to claim 2, wherein a spring having a predetermined spring constant and a damping device having a predetermined damping rate are provided between said floor and said intermediate table in parallel with said actuator.
24. The vibration isolation device according to 2 or 23. 25. The filter according to claim 22, wherein an extension of the actuator provided on the floor is increased or decreased in accordance with an increase or decrease of a load acting on the vibration isolation table. Shaking device. 26. The system according to claim 26, wherein the actuator is a linear actuator such as a voice coil motor, a linear motor, a pneumatic actuator, and a hydraulic actuator, and the control device includes a displacement sensor, a control circuit, and a power amplifier. 27. The vibration isolation device according to any one of 17 to 25.