WO2007007580A1

WO2007007580A1 - Vibration isolation device and vibration isolation method

Info

Publication number: WO2007007580A1
Application number: PCT/JP2006/313243
Authority: WO
Inventors: Takeshi Mizuno
Original assignee: National University Corporation Saitama University
Priority date: 2005-07-13
Filing date: 2006-07-03
Publication date: 2007-01-18
Also published as: JPWO2007007580A1

Abstract

[PROBLEMS] To provide a low cost vibration isolation device capable of isolating vibration caused by ground motion disturbance and direct acting disturbance and realizing zero-compliance over a wide load range. [MEANS FOR SOLVING PROBLEMS] This vibration isolation device comprises a support mechanism supporting a vibration-isolated member (34) having an active first support mechanism (31) with an actuator and a low rigid second support mechanism (32) arranged in series with the first support mechanism (31). The displacement of the actuator of the first support mechanism (31) is controlled to offset the displacement of the second support mechanism (32). Accordingly, even if the vibration due to the ground motion disturbance and the direct acting disturbance occurs, the position of the vibration-isolated member (34) is not changed. The vibration isolation device can isolate the vibration caused by the ground motion disturbance and the direct acting disturbance, realize the zero-compliance over the wide load range, and comprises high reliability. Furthermore, the vibration isolation device can be manufactured at low cost.

Description

Specification

Vibration isolator and vibration isolation method

Technical field

TECHNICAL FIELD [0001] The present invention relates to a vibration isolation device and a vibration isolation method that suppress transmission of vibrations, and in particular, achieves excellent vibration isolation characteristics at low cost.

Background art

In recent years, in a semiconductor device manufacturing system, in order to increase the accuracy of a product, a vibration isolator is applied to the manufacturing apparatus to prevent intrusion of disturbances such as vibration.

As shown in Fig. 10, the vibration propagates from the floor to the equipment (this is called ground disturbance). In order to absorb this ground motion disturbance, a “passive vibration isolation device” that supports a vibration isolation object such as a device or table with a low-rigidity mechanical panel or air panel has been widely used. However, if it is supported only by a low-stiffness panel, vibration F is generated by the disturbance F that directly acts on the vibration isolation object (this is called direct disturbance). Vibration cannot be suppressed.

In addition, as shown in FIG. 11, the object 10 for vibration isolation is supported by the actuator 13, the vibration of the object 10 for vibration isolation is detected by the acceleration sensor 11, and the controller 12 2 cancels the vibration. Both the “active vibration isolator” that drives the actuator 13 and the conventional force are used. However, with this device, it is necessary to use multiple servo-type acceleration sensors that can detect even low-frequency vibrations with high sensitivity (six if two are placed on the x, y, and z planes). Therefore, the active vibration isolator is about 10 times more expensive than the passive vibration isolator.

[0004] In the following Patent Document 1, the present inventors have combined a support mechanism using a panel and a zero power magnetic levitation control mechanism to reduce vibrations caused by ground motion disturbance and linear motion disturbance. Propose.

The zero-power magnetic levitation control mechanism is a mechanism that achieves magnetic levitation using the electromagnet 22 and the permanent magnet 21 attached to the levitation object 28 so as to oppose the electromagnet 22 as shown in FIG. 12 (b). . The suction of the permanent magnet 21 I balance the force and gravity, and the mass m When mass Am is applied to the upper object 28, in order to obtain an increase in attractive force commensurate with the increase in gravity, the energization of the electromagnet 22 is increased, and the permanent magnet 21 is further attracted to the electromagnet 22 side. Is called.

[0005] As shown in FIG. 12 (a), a normal panel having a positive stiffness increases in length as the mass increases due to an increase in mass Am. On the other hand, the zero power magnetic levitation control mechanism can be viewed as a panel having negative rigidity because the distance between the electromagnet 22 and the permanent magnet 21 is shortened when gravity is increased by increasing the mass Δm.

As shown in Fig. 13, when a panel with stiffness kl and a panel with k2 are connected in series, the stiffness kc of the composite panel is given by the following equation.

kc = kl -k2 / (kl + k2)

Therefore, if kl = -k2 is satisfied, I kc I = + ∞.

[0006] Based on this idea, the vibration isolator of Patent Document 1 has zero power that acts as a panel with positive stiffness (kl) 26 and a panel with negative stiffness (one kl), as shown in FIG. Combined with the magnetic levitation control mechanism in series, the overall rigidity (kc) is set to infinity, and vibration of the vibration isolation table 24 due to linear motion disturbance is suppressed. As a result, as shown in Fig. 15 (a), when a direct acting disturbance is applied to the vibration isolation table 24, as shown in Fig. 15 (b), the intermediate is directly connected to the panel 26 with respect to the base 25. Only the base 23 moves and the vibration isolation table 24 does not move.

In addition, vibration due to ground disturbance can be eliminated by setting the panel 26 stiffness (kl) to a small value.

Patent Document 1: Japanese Patent Laid-Open No. 2002-81498

Disclosure of the invention

Problems to be solved by the invention

[0007] However, the vibration isolator of Patent Document 1 has a problem that when the linear motion disturbance is large, the vibration cannot be completely suppressed following the linear motion disturbance (that is, zero compliance cannot be realized). There is.

FIG. 16 shows various loads applied to the vibration isolation table 24 of this vibration isolation device. At that time, the relative displacement of the vibration isolation table 24 with respect to the intermediate base 23, the displacement of the intermediate base 23 with respect to the base 25, and the base 25 The result of measuring the displacement between 24 and 25 is shown. Yes. In Fig. 16, the horizontal axis indicates the magnitude of the downward load in N (Newton), and the vertical axis indicates the magnitude of the upward displacement in mm. The displacement of the vibration isolation table 24 relative to the base 25 is obtained by accounting for the relative displacement of the vibration isolation table 24 relative to the intermediate base 23 and the displacement of the intermediate base relative to the base.

As is apparent from FIG. 16, when the load is about 6 N or more, the displacement of the distance between the vibration isolation table 24 and the base 25 deviates from 0, and zero compliance is not realized. This attraction force F of the permanent magnets, as shown in the following equation, and because the proportional child to 1ZX ² gap distance (X).

F = μ μ Ν Ι

o So X ²

Where is the relative permeability of the gap (1 for air), μ is the vacuum permeability, Ν is the coil 卷

0

The number, S is the gap cross section, and I is the equivalent current determined by the magnetomotive force of the permanent magnet. If the gear changes from X to X—Δ 上, the above equation can be expressed as follows.

F = μ μ N ² Sf / (X— Δ Χ) ²

o

μ Ν Ι ² / Χ ² + 2 μ N

ο ο ² SlVx ³ ) Δ Χ

Where the coefficient of the second term on the left side is 2 μ N ² SI

0 ² ZX ³ ) is the negative stiffness. In other words, the magnitude of negative stiffness is proportional to the third power of the reciprocal of the gap. When a downward load is applied to the vibration isolation table 24, the distance between the intermediate base 23 and the base 25 decreases in proportion to the weight (indicated by a negative displacement in FIG. 16). On the other hand, the gap between the magnet 22 and the permanent magnet 21 of the zero-power magnetic levitation control mechanism is reduced and the magnitude of the negative stiffness is increased, so how to increase the relative displacement of the vibration isolation table 24 relative to the intermediate platform 23 is Get smaller. Therefore, the displacement of the vibration isolation table 24 with respect to the base 25 is shifted to the negative side.

[0009] The present invention solves these conventional problems, and can eliminate vibrations due to ground disturbance and linear disturbance, and can achieve zero compliance over a wide load range. Therefore, the object is to provide a low-cost vibration isolator and a vibration isolation method.

Means for solving the problem

[0010] In the vibration isolation device of the present invention, the support mechanism for supporting the vibration isolation object includes an active first support mechanism having an actuator, and a low-rigidity structure arranged in series with the first support mechanism. Second A support mechanism and a measurement means for measuring the displacement of the second support mechanism, and the displacement of the actuator of the first support mechanism cancels the displacement of the second support mechanism based on the measurement result of the measurement means. To be controlled.

For this reason, the position of the object to be isolated does not change even if vibrations occur due to ground motion disturbance or linear motion disturbance.

[0011] Further, in the vibration isolator of the present invention, the first support mechanism and the second support mechanism are connected in series in the vertical direction so that the second support mechanism is positioned above the first support mechanism. Can be arranged.

In such an arrangement, since the displacement of the second support mechanism caused by the linear motion disturbance can be detected quickly, the effect of improving the response to the linear motion disturbance can be obtained.

In the vibration isolation device of the present invention, the first support mechanism and the second support mechanism are connected in series in the vertical direction so that the first support mechanism is positioned above the second support mechanism. Can be arranged.

In such an arrangement, the mass driven by the actuator can be reduced only to the vibration isolation table, so that the effect of reducing the size of the actuator can be obtained.

[0013] Further, in the vibration isolation device of the present invention, the first support mechanism and the second support mechanism can be arranged in series in the horizontal direction.

With such a configuration, vibration isolation in the horizontal direction can be performed.

[0014] Further, the vibration isolator of the present invention includes an intermediate base supported by an active first support mechanism having an actuator with respect to the floor, and a second rigid low relative to the intermediate base. The vibration isolation table supported by the support mechanism, the measurement means for measuring the displacement of the second support mechanism, and the first support so as to cancel the displacement of the second support mechanism based on the measurement result of the measurement means Control means for controlling the displacement of the actuator of the support mechanism.

In this device, ground disturbance and linear disturbance to the vibration isolation table are absorbed, and vibration is not transmitted to the article placed on the vibration isolation table. In particular, since the displacement of the second support mechanism caused by the linear motion disturbance to the vibration isolation table can be detected quickly, it has a good response to the linear motion disturbance.

[0015] Further, the vibration isolator of the present invention is a medium supported by the second support mechanism having low rigidity with respect to the floor. An intermediate table, an anti-vibration table supported by an active first support mechanism having an actuator with respect to the intermediate table, a measurement means for measuring the displacement of the second support mechanism, and a Control means for controlling the displacement of the actuator of the first support mechanism so as to cancel out the displacement of the second support mechanism based on the measurement result.

In this device, ground disturbance and linear disturbance to the vibration isolation table are absorbed, and vibration is not transmitted to the article placed on the vibration isolation table. Further, since the actuator only needs to drive the vibration isolation table and the article placed thereon, the actuator can be reduced in size.

In the vibration isolator of the present invention, a voice coil motor or a piezoelectric actuator can be used as the actuator of the first support mechanism, and a mechanical panel or an air panel can be used as the second support mechanism.

[0017] Further, the vibration isolation method of the present invention includes an active first support mechanism including an actuator and a low-rigidity second support mechanism arranged in series with the first support mechanism. This is a vibration isolation method that suppresses the linear motion disturbance acting on the vibration isolation object by supporting the object and blocks the ground motion disturbance transmitted from the floor to the vibration isolation object. Then, based on the measurement result, the displacement of the actuator of the first support mechanism is controlled so as to cancel the displacement of the second support mechanism.

The invention's effect

[0018] The vibration isolation device of the present invention is capable of vibration isolation due to ground disturbance and linear disturbance, and can achieve zero compliance over a wide load range, and has high reliability. is doing. Also, this device can be manufactured at low cost.

In addition, the vibration isolation method of the present invention can achieve zero compliance over a wide load range using this vibration isolation device.

Brief Description of Drawings

FIG. 1 is a diagram showing a configuration of a vibration isolation device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a displacement canceling operation of the vibration isolation device according to the embodiment of the present invention. [3] A diagram showing a displacement cancellation control system of the vibration isolation device in the embodiment of the present invention.

[4] A diagram showing a block diagram of a control system of the vibration isolator in the embodiment of the present invention

FIG. 5 is a diagram showing a vibration isolator arranged horizontally in the embodiment of the present invention.

FIG. 6 is a diagram showing an apparatus used for measurement of vibration isolation characteristics of the vibration isolation apparatus in the embodiment of the present invention.

[FIG. 7] A diagram showing a block diagram of a control system for controlling the VCM of the measuring device.

[9] A diagram showing another displacement cancellation control system of the vibration isolation device in the embodiment of the present invention.

[Fig.10] Diagram explaining ground motion disturbance and linear motion disturbance

圆 11] Diagram showing the configuration of a conventional active vibration isolator

圆 12] Illustration of zero power magnetic levitation control mechanism

FIG. 13 is a diagram for explaining the vibration isolation principle of a conventional vibration isolation device

FIG. 14 is a diagram showing the configuration of a conventional vibration isolator

FIG. 15 is a diagram for explaining the vibration isolation operation of a conventional vibration isolation device.

FIG. 16 is a diagram showing vibration isolation characteristics of a conventional vibration isolation device

Explanation of symbols

10 Anti-vibration object

11 Accelerometer

12 Controller

13 Actuator

21 Permanent magnet

22 Electromagnet

23 Intermediate stand

24 Vibration isolation table

25 base

26

28 Ascent object

31 First support mechanism 32 Second support mechanism

33 Intermediate stand

34 Vibration isolation table

35 base

36 Linear slider

41 Controller

42 Amplifier

43 VCM

44 Strain gauge sensor

45 Distortion amplifier

46 DSP

47 PD section

48 integrator

49 Subtractor

50 Subtractor

51 amplifier

BEST MODE FOR CARRYING OUT THE INVENTION

As shown in FIG. 1, the vibration isolator according to the embodiment of the present invention includes a base 35, an intermediate base 33, a vibration isolation table 34, and a first base that is on the base 35 and supports the intermediate base 33. 1 The support mechanism 31 and the second support mechanism 32 provided on the intermediate base 33 and supporting the vibration isolation table 34 are provided with a low rigidity. It expands and contracts in response to the applied linear motion disturbance. In addition, the second support mechanism 32 absorbs vibration due to ground motion disturbance that propagates through the base 35 and suppresses propagation of the vibration to the vibration isolation table 34.

On the other hand, the first support mechanism 31 is an active support mechanism having an actuator, and the actuator is controlled so as to cancel the displacement of the distance between the vibration isolation table 34 and the intermediate base 33, and this control is immediately performed. It has a quick response.

FIG. 2 shows the first support mechanism 31 and the second support mechanism when a linear motion disturbance is applied to the vibration isolation table 34. The state of displacement of the support mechanism 32 is shown. As shown in Fig. 2 (a), the second support mechanism 32 keeps the distance between the vibration isolation table 34 and the intermediate base 33 at xl, and the first support mechanism 31 sets the distance between the intermediate base 33 and the base 35 to x2. When this is maintained, a linear motion disturbance is applied to the vibration isolation table 34, the second support mechanism 32 contracts as shown in Fig. 2 (b), and the distance between the vibration isolation table 34 and the intermediate base 33 becomes (xl Assume that ΔX) has changed.

[0023] The displacement of the distance between the vibration isolation table 34 and the intermediate base 33 is detected by, for example, a mechanical or optical gap sensor or the like, and the first support mechanism 31 determines that the intermediate base 33 It is controlled to keep the distance between the bases 35 at (χ2 + Δχ). As a result, the distance L between the vibration isolation table 34 and the base 35 is

L = (χ1-Δ χ) + (χ2 + Δ χ)

= xl + x2

Thus, the original distance is maintained (note that the thickness of the intermediate stage 33 is assumed to be 0 for the sake of simplicity).

In this way, in this vibration isolation device, as shown in FIG. 3, the displacement information of the second support mechanism 32 is input to the controller 41 that controls the actuator of the first support mechanism 31, and the controller 41 is Then, a control signal for generating a displacement that cancels out the displacement of the second support mechanism 32 to the first support mechanism 31 is generated. This control signal is amplified by the amplifier 42 and input to the first support mechanism 31, and the first support mechanism 31 is displaced according to the control signal. As a result, the displacement of the second support mechanism 32 is canceled out.

FIG. 4 is a block diagram illustrating an example of a control system that controls the first support mechanism 31. This control system includes a VCM (Voice Coil Motor) 43 that constitutes the actuator of the first support mechanism 31, a strain gauge sensor 44 that measures the displacement x of the movable part of the VCM 43, and a strain amplifier 45 that converts strain into an electrical signal. And a DSP (Digital Signal Processor) 46 that constructs a control system for IPD control (proportional derivative precedence type PID control), and an amplifier 51 that converts the voltage output from the DSP 46 into current.

The DSP 46 also includes a subtractor 49 that subtracts the input signal from the command value ei (V) force, an integrator 48 that performs the integration operation of the output of the subtractor 49, and a PD unit that performs the proportional operation and differentiation operation of the input signal. And a subtractor 50 for subtracting the output of the PD unit 47 from the output of the integrator 48. finger The command value ei is given a signal that cancels out the displacement of the second support mechanism 32.

[0026] The equation in VCM43 shows the transfer function of VCM, Ki is the VCM thrust coefficient (N / A), m is the mass of the moving part of VCM (kg), k is the panel constant of the panel in VCM ( NZm), s is a variable. C of the strain gauge sensor 44 indicates a sensor gain (ε Zm). Ka of the distortion amplifier 45 indicates the distortion amplifier gain (VZ ε). DSP46's Pi, Pd, and Pv represent integral gain, proportional gain, and differential gain. Also, Kb of the amplifier 51 indicates the amplifier gain (AZV)! /

After the control parameters of this control system are obtained experimentally, cancellation control is executed.

Next, characteristics of the vibration isolator will be described.

In order to measure this characteristic, as shown in FIG. 5, the base 35, the first support mechanism 31, the intermediate base 33, the second support mechanism 32, and the vibration isolation table 34 are arranged horizontally, and the intermediate base 33 and the vibration isolation table 34 are The vibration isolator supported by the linear slider 36 was used so that the table 34 could move without friction with the ground. Figure 6 shows the vibration isolation device actually used for the measurement. In this apparatus, the first support mechanism 31 is composed of VCM, and the second support mechanism 32 is composed of VCM so that arbitrary rigidity can be obtained. FIG. 7 shows a control system that controls the VCM of the second support mechanism 32. Compared to the control system in Fig. 4, this control system is configured to input a signal specifying the initial displacement of the second support mechanism as the command value ei, and to construct a control system for PD control with DSP46. However, the points are different.

In addition, the VCM37 for generating disturbance is installed in the equipment shown in Fig. 6. In addition, in order to measure the horizontal displacement of the vibration isolation table 34 and the intermediate base 33, a gap sensor 38 with a strain gauge attached to the panel panel is connected between the vibration isolation table 34 and the intermediate base 33, and the intermediate base 33. Place yourself between 33 and base 35!

[0028] Fig. 8 shows the VCM 37 for disturbance generation, where a horizontal load was applied to the vibration isolation table 34, and the “displacement of the distance between the vibration isolation table 34 and the intermediate base 33” “intermediate base 33—base 35” The results of the measurement of the “displacement of the distance between” and “the displacement of the distance between the vibration isolation table 34 and the base 35” are shown. The horizontal axis shows the load in N (Newton) and the vertical axis shows the magnitude of displacement in mm. “Displacement of the distance between the vibration isolation table 34 and the base 35” refers to “Displacement of the distance between the vibration isolation table 34 and the intermediate base 33” and “Displacement of the distance between the intermediate base 33 and the base 35”. It will be added.

As is clear from this figure, the displacement of the distance between the vibration isolation table 34 and the base 35 is substantially zero over a wide range of loads, and zero compliance is realized.

[0029] As described above, this vibration isolation device is capable of vibration isolation due to ground motion disturbance and linear motion disturbance, and can realize zero compliance over a wide load range. In addition, since an expensive servo-type acceleration sensor is not required !, it can be manufactured at low cost.

[0030] It should be noted that here, even with the force and other actuators (for example, piezoelectric actuators, etc.) shown in the example in which the first support mechanism 31 is configured by VCM, the one having the rapid response that can be applied to the displacement cancellation control. If so, the first support mechanism 31 can be used. Further, the second support mechanism 32 may be a machine panel or an air panel having low rigidity.

In addition, as shown in FIG. 5 in which the vibration isolator is simply installed vertically, it can be arranged horizontally and used for suppressing horizontal vibration.

[0031] Also, here, a first support mechanism 31 having an actuator is disposed between the base 35 and the intermediate base 33, and a second low-rigidity second is provided between the intermediate base 33 and the vibration isolation table 34. The case where the support mechanism 32 is disposed has been described. Conversely, as shown in FIG. 9, the second support mechanism 32 is disposed between the base 35 and the intermediate base 33, and the first support mechanism 31 is disposed. It may be arranged between the intermediate table 33 and the vibration isolation table 34. With this arrangement, the mass driven by the actuator can be made only by the vibration isolation table, so that the effect of reducing the size of the actuator can be obtained.

Industrial applicability

[0032] The vibration isolator of the present invention includes a semiconductor manufacturing system, an ultraprecision measuring device such as a scanning tunneling microscope (STM) and an atomic force microscope (AFM), an ultraprecision processing machine that performs laser processing and nanoscale processing. Or, it can be widely used for vibration isolation of various devices that do not like vibration, such as devices in the cutting-edge fields that handle bio micro-duplication and nanotechnology.

Claims

The scope of the claims

[1] The support mechanism for supporting the vibration isolation object includes an active first support mechanism including an actuator, and a low-rigidity second support mechanism arranged in series with the first support mechanism; Measuring means for measuring the displacement of the second support mechanism, and the displacement of the actuator of the first support mechanism is changed based on the measurement result of the measurement means. An anti-vibration device controlled to cancel the position.

[2] The vibration isolation device according to claim 1, wherein the first support mechanism and the second support mechanism are located above the first support mechanism. Thus, the vibration isolator is arranged in series in the vertical direction.

[3] The vibration isolation device according to claim 1, wherein the first support mechanism and the second support mechanism are located above the second support mechanism. Thus, the vibration isolator is arranged in series in the vertical direction.

4. The vibration isolation device according to claim 1, wherein the first support mechanism and the second support mechanism are arranged in series in the horizontal direction.

[5] An intermediate base supported by an active first support mechanism having an actuator with respect to the floor, and a vibration isolation table supported by the second support mechanism having a low rigidity with respect to the intermediate base Measuring means for measuring the displacement of the second support mechanism; and based on the measurement result of the measurement means, the first support mechanism is configured to cancel out the displacement of the second support mechanism. A vibration isolation device comprising: control means for controlling the displacement of the actuator.

[6] An intermediate table supported by a low-stiffness second support mechanism with respect to the floor, and an anti-vibration table supported by the active first support mechanism having an actuator with respect to the intermediate table And measuring means for measuring the displacement of the second support mechanism, and the first support mechanism actuating so as to cancel the displacement of the second support mechanism based on the measurement result of the measurement means. And a vibration control device for controlling the displacement of the vibration isolator.

[7] The vibration isolator according to any one of claims 1 to 6, wherein the actuator of the first support mechanism is a voice coil motor or a piezoelectric actuator, and the second support mechanism is a mechanical panel or an air panel. An anti-vibration device characterized by

[8] An active first support mechanism including an actuator, and the first support mechanism in series By supporting the vibration isolation object with the low-stiffness second support mechanism, the linear motion disturbance acting on the vibration isolation object is suppressed, and the ground disturbance transmitted to the floor vibration isolation object is blocked. A vibration isolation method,

The displacement of the second support mechanism is measured, and the displacement of the actuator of the first support mechanism is controlled so as to cancel the displacement of the second support mechanism based on the measurement result. Vibration isolation method.