JP2002372098A - Vibration isolator and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration isolator and a control method capable of substantially reducing the attitude change of a vibration isolating mount. SOLUTION: Multiple actuators 26 and 27 actuating a vertical drive force are provided from a lower side of the vibration isolating mount 21 mounting a device having an XY stage 20. An actuator generation force setting means 37 applies an actuator generation force command value increasing the drive force according to a stage moving distance to the actuator 27 in a side of the moving directional of the XY stage 20 and the actuator generation force command value decreasing the drive force according to a stage moving distance to the actuator 26 in a side of the separating direction of the XY stage 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration apparatus equipped with a precision instrument having an XY stage and a method of controlling the same, and more particularly to a posture change caused by a movement of a load of the mounted equipment by driving the XY stage. The present invention relates to a vibration damping device and a control method for reducing noise.

[0002]

2. Description of the Related Art Conventionally, as a defect inspection apparatus for inspecting minute defects on a surface such as a semiconductor or a liquid crystal substrate, an apparatus using an optical microscope is known.

In such a defect inspection apparatus, a high-resolution optical microscope is used, and under this microscope, a semiconductor and a liquid crystal substrate to be inspected are moved and positioned by an XY stage to perform a defect inspection. However, if a high-resolution optical microscope is used, even a slight external vibration will greatly affect the observation result, so the entire apparatus is installed on the vibration isolator.

FIG. 6 shows an example of such an anti-vibration apparatus. An anti-vibration table 3 on which an apparatus having an XY stage 2 controlled by a stage control apparatus 1 such as the above-mentioned defect inspection apparatus is mounted is mounted on an actuator. As a plurality of air springs 4
The air spring 4 is supplied with air from an air compression source 5, and the amount of supplied air is controlled by the leg 6 and the vibration isolation table 3.
In accordance with the deviation between the output of the displacement detecting means 7 for detecting the relative displacement during the operation and the level target value 8, the supply / exhaust of the supply / exhaust adjusting valve 10 is controlled via the level maintaining device 9 to generate the actuator generating force at the air spring 4. Is adjusted to maintain the posture level of the vibration isolation table 3 at a constant level.

According to such a vibration isolator, the air spring 4
By supporting the vibration isolation table 3, the vibration from the floor can be attenuated and not transmitted to the devices on the vibration isolation table 3. In this case, since the air spring 4 has a property of absorbing and damping vibration, it has a structure and properties that are easily deformed. For this reason, even when a device is mounted on the anti-vibration table 3 without considering the balance of the center of gravity, the deviation between the output of the displacement detecting means 7 and the level target value 8 is maintained so that the anti-vibration table 3 can be kept horizontal. The supply / exhaust adjusting valve 1 is controlled by the level maintaining device 9 based on the
A closed loop is formed such that the air spring 4 is expanded and contracted by adjusting 0.

However, when the equipment mounted on the vibration isolation table 3 includes the XY stage 2, when the XY stage 2 is moved by the stage controller 1, a load shift occurs on the vibration isolation table 3. For example, as shown in FIG. 7A, when the XY stage 2 moves from a state in which the vibration isolation table 3 is kept horizontal, as shown in FIG. The load applied to the air spring 4 increases, and the anti-vibration table 3 inclines so as to descend in the direction in which the XY stage 2 has moved, as much as the air spring 4 is compressed. In this case, the actuator generating force of the air spring 4 by the above-described level maintaining device 9 acts even during the movement of the XY stage 2, but cannot follow the movement of the XY stage 2, so that the vibration isolation table 3 Without returning to the position and posture,
After the XY stage 2 is displaced until it sinks on the moved side, it returns to the original posture. For this reason, there is a problem that a considerable time is required until the posture is returned, and the work must be stopped and waited from the stage movement until the microscope observation becomes possible.

FIG. 9 illustrates the operation of various parts in such a vibration damping device. The force generated by the actuator of the air spring 4 in the stage movement direction is different from the movement of the stage shown in FIG. , And act with a delay as shown in FIG. For this reason, an acceleration is generated in the mounted device due to the change in the posture of the vibration isolation table 3 during this time, and a large fluctuation occurs in the deviation signal as shown in FIG.
As shown in 2), a large posture change occurs in the vibration isolation table 3 as a vertical displacement.

Therefore, in order to speed up the return to the attitude of the vibration isolation table 3, it is conceivable to increase the gain of the level maintaining device 9. However, in this case, a slight change in the attitude of the vibration isolation table 3 due to vibration disturbance or the like is considered. Therefore, the force generated by the actuator in the air spring 4 is increased, and the vibration isolator 3 is more likely to vibrate. It is also conceivable to reduce the change in the attitude of the vibration isolation table 3 without increasing the gain of the level maintaining device 9 and to speed up the return to the attitude by lowering the moving speed of the XY stage 2. In defect inspection of a substrate or the like, work efficiency is regarded as important, and it is required that the moving speed of the XY stage 2 be as high as possible.

To solve such a problem, Japanese Patent Laid-Open No.
Japanese Unexamined Patent Publication No. 252822 discloses a method. FIG.
Is disclosed in this publication, and the same parts as those in FIG. 6 described above are denoted by the same reference numerals. In this case, instead of the level target value 8 described in FIG.
a, a target level setting means 11 having an operation section 11c for changing the target level setting values 11a, 11b for the level maintaining device 9 based on a stage drive signal from the stage control device 1; By controlling the actuator generation force of the air spring 4 on the movement direction side of the actuator 2 to be large and the actuator generation force of the air spring 4 on the side where the XY stage 2 moves away, the posture change of the vibration isolation table 3 can be reduced. It is made smaller to shorten the settling time of the posture return. That is, FIG.
When there is a stage movement shown in FIG. 5, the target level setting means 11 synchronizes with the movement of the stage,
To change. In this case, the target level set value 11b corresponding to the moving direction side of the XY stage 2 becomes a predetermined level value in the positive direction as shown in FIG. Is a predetermined level value in the negative direction opposite to the predetermined level value in the positive direction. Then, on the movement direction side of the XY stage 2, the deviation input to the level maintaining device 9 increases, and a large actuator generating force is generated. Conversely, on the side where the XY stage 2 moves away, the input to the level maintaining device 9 is performed. The resulting deviation is reduced, and the force generated by the actuator is suppressed, so that the posture change of the vibration isolation table 3 due to the stage movement can be suppressed.

[0010]

However, according to the configuration described above, the control system for maintaining the level including the displacement detecting means 7 and the like actually has an inherent delay element. Due to the delay element, the deviation signal input to the level maintaining device 9 has a dull waveform as shown in FIG. 9 (b3). As a result, the force generated by the actuator in the air spring 4 also has a dull waveform with a delay as shown in FIG. 5B, so that the timing of suppressing the change in the posture of the anti-vibration table 3 due to the force generated by the actuator is delayed. However, the vibration isolation table 3 still has a problem that a posture change occurs as a vertical displacement as shown in FIG.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vibration damping apparatus and a control method capable of greatly reducing a change in the posture of a vibration damping table.

[0012]

According to the first aspect of the present invention,
An anti-vibration table mounted with a device that causes load movement and supported to be able to move vertically, a plurality of actuators for applying an upward driving force to the anti-vibration table, and An anti-vibration apparatus comprising: a displacement detection unit that detects a displacement in a moving direction; and a level maintaining mechanism that performs feedback control on the actuator in order to maintain a vertical movement position of the anti-vibration table at a predetermined target value. And controlling the driving force of the plurality of actuators based on the moving state of the load of the device so as to generate a driving force that cancels a change in the load acting on the plurality of actuators caused by the load movement of the device. And control means.

According to a second aspect of the present invention, in the first aspect of the present invention, the control means includes a driving force applied to one of the plurality of actuators, the load acting on the actuator being increased by a load movement of the device. , And is controlled so as to reduce the driving force in response to a decrease in the applied load.

According to a third aspect of the present invention, there is provided an anti-vibration table mounted with a device which generates a load movement and supported so as to be able to move up and down, and applies an upward driving force to the anti-vibration table. In a vibration isolator including a plurality of actuators, the load acting on the actuator is increased by the load movement of the device so as to offset a variation in the load acting on the plurality of actuators caused by the load movement of the device. On the other hand, each of the plurality of actuators is controlled so that the driving force is increased and the driving force is reduced in response to a decrease in the applied load.

As a result, according to the present invention, even if a load shift occurs on the vibration isolation table, the actuator in the direction of the load shift gradually increases the driving force, and conversely, on the side where the load shifts away. In this actuator, the driving force gradually decreases, so that the posture of the vibration isolation table can be stably maintained even during the load movement.

Further, since the driving force of the actuator is directly controlled by the actuator control means, it is possible to prevent the delay element inherent in the control system for maintaining the level of the vibration isolation table from adversely affecting the attitude maintenance of the vibration isolation table. it can.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a schematic configuration of a vibration isolator to which the present invention is applied. In the figure, reference numeral 21 denotes a rectangular anti-vibration table, on which a defect inspection apparatus having an XY stage 20 controlled by a stage control device 19 is mounted.
There are a plurality of anti-vibration tables 21 (four corresponding to the four corners of the anti-vibration table 21 in the illustrated example, only two of them are shown, and the remaining 2
(Not shown) are supported by legs 24, 25 via vibration-proof support members 22, 23 as vibration-proof support means. A spring material or a rubber material is used for the vibration isolation support members 22 and 23.

Also, between the legs 24 and 25 and the vibration isolating table 21, there are also a plurality (four corresponding to the four corners of the vibration isolating table 21 in the illustrated example, of which only two are shown, and the remaining two are shown). (Not shown) are provided. These actuators 26 and 27 apply a vertical driving force from the lower surface side of the vibration isolation table 21.
As the actuators 26 and 27, an electromagnetic actuator, an air spring, a pneumatic cylinder, a hydraulic cylinder, or the like is used. In this case, the actuators 26 and 27
Are fixed to the legs 24 and 25 and apply a force to the vibration isolation table 21, so that the vibration isolation table 21 and the actuator 26,
If the connection (contact) of the 27 is rigid, the vibration of the legs 24 and 25 will be transmitted to the vibration isolation table 21 via the actuators 26 and 27. Therefore, the connection between the actuators 26 and 27 and the vibration isolation table 21 is desirably configured to have a vibration isolation effect. Specifically, a configuration is conceivable in which the working ends of the actuators 26 and 27 are connected to the vibration isolation table 21 via a viscoelastic member such as a rubber material. If an air spring is used, it can be used as both an anti-vibration support member and an actuator.
Such considerations need not be taken into account.

The legs 24 and 25 are provided with displacement detectors 2 as displacement detecting means for detecting relative displacement between the legs 24 and 25.
8, 29 are provided.

The displacement detectors 28 and 29 are provided with the comparator 3
0 and 31 are connected to one input terminal. A target value for maintaining the vibration isolation table 21 at a predetermined position, that is, a level target value (= 0 horizontal) 32 is provided to the other input terminals of the comparators 30 and 31. These comparators 3
Numerals 0 and 31 compare the displacement outputs of the displacement detectors 28 and 29 with the level target value 32 and output a deviation signal.

The comparators 30 and 31 are connected to level maintaining devices 33 and 34, respectively. These level maintaining devices 33 and 34 adjust the actuator generating force necessary to maintain the posture level of the vibration isolation table 21 constant based on the deviation signals from the comparators 30 and 31.

The level maintaining devices 33 and 34 include an adder 3
One of the input terminals 5 and 36 is connected. The other input terminals of the adders 35 and 36 are connected to actuator generating force setting means 37 as actuator control means.

This actuator generating force setting means 37
Are the calculation unit 37a, the generation force command value generation units 37b and 37c
When the information about the movement of the XY stage 20 output from the stage control device 19 is received, the actuator 2 receives the information from the generated force command value generation units 37b and 37c.
An actuator generation force command value is output to actuators 6 and 27 as an actuator control command. In this case, the actuator force command value output from the force command value generation units 37b and 37c increases in accordance with the stage movement distance on the movement direction side of the XY stage 20, and conversely, on the side where the XY stage 20 moves away. Thus, the distance is reduced in accordance with the moving distance of the stage. That is, of the four actuators 26 and 27 supporting the vibration isolation table 21, the actuator 2 is moved by the movement of the XY stage 20.
The driving force is increased when the load acting on the elements 6 and 27 increases, and the driving force is decreased when the acting load decreases. In the illustrated example, the actuator generated force command value and the generated force command value generation unit 37 decrease from the generated force command value generation unit 37b according to the stage moving distance.
From c, an actuator generation force command value that increases in accordance with the stage moving distance is output. These actuator generated force command values are used to determine the load fluctuation when the XY stage 20 moves to the target position.
6 and 27 are set to values that cancel out the actuator generated force.
Is calculated by

The generated force command value generating section 37
b, 37c, the actuator generating force command values are added to the level maintaining devices 33, 34 by the adders 35, 36.
And the output from each actuator 2
6, 27.

Next, the operation of the embodiment configured as described above will be described.

Now, when the XY stage 20 mounted on the vibration isolation table 21 is controlled to move in the direction indicated by the arrow in FIG.
Information about the movement of the XY stage 20 is output from 9 and given to the actuator generating force setting means 37.

In the actuator generating force setting means 37,
When the information about the movement of the XY stage 20 is received from the stage control device 19, the generated force command value generating section 37c on the moving direction side of the XY stage 20 generates an actuator generated force command value that increases according to the stage movement distance. On the other hand, the generated force command value generator 37b on the side where the XY stage 20 moves away generates an actuator generated force command value that decreases in accordance with the stage movement distance.
These actuator generation force command values are added to adders 35, 3
6 to actuators 26 and 27.

Accordingly, even if the XY stage 20 moves in the direction indicated by the arrow and a load moves on the vibration isolation table 21, the actuator 27 on the moving direction side of the XY stage 2 can move.
Then, an actuator generation force command value that increases in accordance with the stage moving distance is given, and the actuator generation force (driving force) is gradually increased. Conversely, in the actuator 26 on the side where the XY stage 20 moves away, When the XY stage 2 moves on the anti-vibration table 21, the actuator generation force command value that decreases in accordance with the stage movement distance is given, and the actuator generation force (driving force) gradually decreases. Irrespective of the above, the posture of the vibration isolation table 21 is kept constant.

On the other hand, the outputs of displacement detectors 28 and 29 for detecting the relative displacement between the legs 24 and 25 and the vibration isolation table 21 are given to comparators 30 and 31 and compared with a level target value 32. . In this case, during the series of operations described above, the vibration isolation table 21
Does not affect the outputs of the adders 35 and 36 if the deviation from the level target value 32 is zero, but if a slight change in posture occurs on the vibration isolation table 21 for some reason, When this occurs, the outputs of the displacement detectors 28 and 29 change, so that the comparators 30 and 31 generate deviations according to changes in the attitude of the vibration isolation table 21. Then, this deviation is provided to adders 35 and 36 via level maintaining devices 33 and 34,
Generated force command value generator 37b and generated force command value generator 3
It is added to the actuator generating force command value generated by 7c and is given to the actuators 26 and 27, whereby the posture change of the vibration isolation table 21 is corrected.

In other words, when the stage is moved as shown in FIG. 2A, the actuator force setting means 37 generates a force command value generator 37c on the moving direction side of the XY stage 20 as shown in FIG. As shown in the figure, an actuator force command value which increases in accordance with the stage movement distance in the forward direction is generated. An actuator generating force command value that decreases is generated. Thus, the actuator 27 on the movement direction side of the XY stage 20 gradually increases the actuator generation force (driving force) as shown in FIG. 3E, and conversely, the actuator 2 on the side where the XY stage 20 moves away.
6, the actuator generated force (driving force) is gradually reduced. At this time, the actuator generated force command value is determined by the load fluctuation when the XY stage 20 moves to the target position. Since the actuator generation force is set to cancel each other, the posture of the vibration isolation table 21 does not change as shown in FIG.
Even while the XY stage 20 is moving, the posture of the vibration isolation table 21 can be kept constant.

Accordingly, even if the XY stage 20 moves in the direction indicated by the arrow and a load moves on the anti-vibration table 21, the actuator 27 on the moving direction side of the XY stage 2 can move the stage by the moving distance. , The actuator generation force (driving force) gradually increases, and conversely, XY
In the actuator 26 on the side where the stage 20 moves away,
Since the actuator generating force (driving force) gradually decreases according to the stage moving distance, the XY stage 2
The posture of the vibration isolation table 21 can be stably maintained even during the movement of.

The actuator generating force setting means 37
, The actuator generating force of the actuators 26 and 27 is directly controlled by the displacement detector 2.
Even if the control system for maintaining levels including 8, 29, and the like has delay elements specific to them, it is possible to prevent the delay elements from adversely affecting the attitude maintenance of the vibration isolation table 21. Further, since the level target value 32 of the level maintaining devices 33 and 34 is always constant, it is possible to prevent the influence of the fluctuation of the level target value.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described.

FIG. 3 shows a schematic configuration of a second embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

In this case, an anti-vibration table 21 on which equipment such as a defect inspection apparatus having an XY stage 20 controlled by a stage controller 19 is mounted on legs 24, 25 by air springs 41, 42. I have.

These air springs 41 are connected to an air compression source 451 via supply and exhaust adjustment valves 43 and 46 arranged in parallel, and the air spring 42 controls supply and exhaust adjustment valves 44 and 47 arranged in parallel. It is also connected to the air compression source 452 via this. The air compression sources 451 and 452 are
2 for supplying compressed air.

The supply and exhaust of the supply and exhaust adjustment valves 43 and 44 are controlled by the outputs of the level maintaining devices 33 and 34, and the supply and exhaust adjustment valves are controlled by the outputs of the output signal generators 48b and 48c of the actuator generating force setting means 48. 46, 4
7 is controlled. In this case, the actuator generating force setting means 48 has a calculating section 48a and output signal generating sections 48b and 48c. When the information about the movement of the XY stage 20 output from the stage control device 19 is received, the output signal generating section 48 48b, 48c
Further, an output signal for controlling the supply and exhaust of the supply and exhaust adjustment valves 46 and 47 is generated. An output signal generator 48b,
An output signal generated from the XY stage 20c is an “ON” signal on the movement direction side of the XY stage 20.
On the side that is farther away, the signal is turned off.
In the illustrated example, the output signal generation unit 48b sends the air supply / exhaust adjustment valve 4
An "off" signal for instructing the exhaust of No. 6 and an "on" signal for instructing the air supply of the air supply / exhaust adjusting valve 47 from the output signal generating section 48c are generated.

In such a configuration, when the XY stage 20 mounted on the anti-vibration table 21 is controlled to move in the direction indicated by the arrow in FIG. Information on the movement of the actuator 20 is output and given to the actuator generating force setting means 48.

In the actuator generating force setting means 48,
When the information about the movement of the XY stage 20 is received from the stage control device 19, an “ON” signal that instructs the air supply / exhaust adjustment valve 47 to supply air from the output signal generator 48c on the movement direction side of the XY stage 20 is output. On the other hand, the output signal generator 4 on the side where the XY stage 20 moves away
8b, an "OFF" signal is generated to instruct the supply / exhaust adjusting valve 46 to exhaust.

The degree of opening of the supply / exhaust adjusting valves 46 and 47 based on the "ON" and "OFF" signals is adjusted by the amount of stage movement.
For example, when the moving amount of the stage is large or when the moving time of the stage is short, the amount of supply / exhaust air per unit time increases, so that the degree of opening of the supply / exhaust adjusting valves 46 and 47 increases.
The opening degree of the supply / exhaust adjustment valves 46 and 47 is determined by the current coordinates of the stage
The calculation unit calculates the movement amount and the movement speed of the stage.

Thus, even if the load movement occurs on the vibration isolator 21 with the movement of the XY stage 20 in the direction of the arrow shown in the figure, the air spring 42 on the movement direction side of the XY stage 2
The actuator generating force (driving force) gradually increases in accordance with the stage moving distance, and conversely, the air spring 41 on the side where the XY stage 20 moves away gradually increases the actuator generating force (driving force) in accordance with the stage moving distance. Therefore, the attitude of the vibration isolation table 21 is maintained constant regardless of the movement of the XY stage 2 on the vibration isolation table 21.

Therefore, even in this case, the same effect as that described in the first embodiment can be expected. Further, this embodiment can be realized only by adding the actuator generating force setting means 48 and the supply / exhaust adjusting valves 46 and 47 to the conventional structure described in FIG. 6, so that the existing device can be effectively used. It can be economically advantageous.

In the above description, the supply / exhaust control of the supply / exhaust control valves 46, 47 by the output signal generating sections 48b, 48c of the actuator generating force setting means 48, and the supply / exhaust control valve by the outputs of the level maintaining devices 33, 34. The control of the supply and exhaust of the 43 and 44 is used together. For example, as shown in FIG.
The supply / exhaust control of the supply / exhaust control valves 3 and 44 may be omitted, and only the control of the supply / exhaust of the supply / exhaust adjustment valves 46 and 47 by the output signal generators 48 b and 48 c of the actuator generating force setting means 48 may be performed.
The same effect as described above can be expected.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
An embodiment will be described.

FIG. 5 shows a schematic configuration of the third embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

In this case, the anti-vibration table 21 on which equipment such as a defect inspection device having an XY stage 20 controlled by the stage control device 19 is supported by the legs 24 and 25 by air springs 51 and 52. Together with the vibration isolation table 21
Actuators 53 and 54 for applying a vertical driving force to the actuator are provided. Also in this case, since the actuators 53 and 54 are fixed to the legs 24 and 25 and apply a force to the vibration isolation table 21, the connection (contact) between the vibration isolation table 21 and the actuators 53 and 54 is rigid. And leg 2
The vibrations of 4 and 25 are transmitted to the vibration isolation table 21 via the actuators 53 and 54. Therefore, the actuator 5
It is desirable that the connection between the vibration dampers 3 and 54 and the vibration isolation table 21 be configured to have a vibration isolation effect. Specifically, a configuration is conceivable in which the working ends of the actuators 53 and 54 are connected to the vibration isolation table 21 via a viscoelastic member such as a rubber material.

The air spring 51 is connected to an air compression source 561 via a supply / exhaust adjustment valve 55, and the air spring 52 is also connected to an air compression source 562 via a supply / exhaust adjustment valve 57. The supply and exhaust of the supply and exhaust adjustment valves 55 and 57 are controlled by the outputs of the level maintaining devices 33 and 34.

The actuator generating force setting means 37
Receives the information on the movement of the XY stage 20 output from the stage control device 19, and outputs the actuator force command values for the actuators 53 and 54 from the force command value generators 37b and 37c. The generated force command value generating units 37b, 37
The actuator generating force command value output from c is directly supplied to the actuators 53 and 54.

In such a configuration, when the XY stage 20 mounted on the anti-vibration table 21 is controlled to move in the direction shown by the arrow in the drawing according to the instruction of the stage controller 19, the stage controller 19 simultaneously controls the XY stage. Information on the movement of the actuator 20 is output and given to the actuator generating force setting means 37.

In the actuator generating force setting means 37,
When the information about the movement of the XY stage 20 is received from the stage control device 19, the generated force command value generating section 37c on the moving direction side of the XY stage 20 generates an actuator generated force command value that increases according to the stage movement distance. On the other hand, the generated force command value generator 37b on the side where the XY stage 20 moves away generates an actuator generated force command value that decreases in accordance with the stage movement distance.
These actuator generation force command values are directly given to the actuators 53 and 54.

Thus, even if the XY stage 20 moves in the direction indicated by the arrow and a load moves on the vibration isolation table 21, the actuator 54 on the moving direction side of the XY stage 2 can move.
Then, the actuator generating force (driving force) is gradually increased in accordance with the stage moving distance. Conversely, in the actuator 53 on the side where the XY stage 20 moves away, the actuator generating force (driving force) is gradually increased in accordance with the stage moving distance. Therefore, the attitude of the vibration isolation table 21 is maintained constant regardless of the movement of the XY stage 2 on the vibration isolation table 21.

On the other hand, the outputs of the displacement detectors 28 and 29 for detecting the relative displacement between the legs 24 and 25 and the anti-vibration table 21 are given to the comparators 30 and 31 and compared with the level target value 32. . In this case, if a slight change in the posture of the vibration isolation table 21 occurs for any reason, the outputs of the displacement detectors 28 and 29 change. Occurs. This deviation is supplied to the supply / exhaust adjusting valves 55, 5 via the level maintaining devices 33, 34.
7 to control its supply and exhaust. Thereby, the expansion and contraction state of the air springs 51 and 52 is changed, and thereby,
The posture change of the vibration isolation table 21 is corrected.

Therefore, even in this case, the same effect as that described in the first embodiment can be expected. Further, the air springs 51, 52 and the actuators 53, 54 are used in combination, and the actuator generation force setting means 37 directly supplies the actuator generation force command value to the actuators 53, 54.
By selecting 4, an operation with good responsiveness can be obtained.

[0055]

As described above, according to the present invention, it is possible to provide an anti-vibration apparatus and a control method capable of greatly reducing the change in the attitude of the anti-vibration table.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the first embodiment.

FIG. 3 is a diagram showing a schematic configuration of a second embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a modification of the second embodiment.

FIG. 5 is a diagram showing a schematic configuration of a third embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of an example of a conventional vibration damping device.

FIG. 7 is a diagram for explaining a problem of the conventional vibration isolator.

FIG. 8 is a diagram showing a schematic configuration of another example of the conventional vibration isolator.

FIG. 9 is a view for explaining the operation of each part of the conventional vibration isolator.

[Explanation of symbols]

 Reference Signs List 19 stage control device 20 XY stage 21 anti-vibration table 22.23 anti-vibration support member 24.25 leg 26.27 actuator 28.29 displacement detector 30.31 comparator 32 level target Value 33.34 Level maintaining device 35.36 Adder 37 Actuator generating force setting means 37a Operation unit 37b. 37c: Generated force command value generator 41.42 ... Air spring 43.44 ... Supply / exhaust adjustment valve 451.452 ... Air compression source 46.47 ... Supply / exhaust adjustment valve 48 ... Actuator generation force setting means 48a ... Calculation unit 48b. 48c: output signal generator 51.52: air spring 53.54: actuator 55.57: supply / exhaust adjustment valve 561, 562: air compression source

Claims (3)

[Claims] 1. An anti-vibration table mounted with a device that generates a load movement and supported so as to be able to move up and down, a plurality of actuators for applying an upward driving force to the anti-vibration table, Displacement detecting means for detecting the vertical movement of the vibration isolation table, and a level maintaining mechanism for performing feedback control on the actuator to maintain the vertical movement direction position of the vibration isolation table at a predetermined target value. In the vibration isolator provided, to generate a driving force to offset the variation of the load acting on the plurality of actuators caused by the load movement of the device, the plurality of actuators of the plurality of actuators based on the movement state of the load of the device A vibration isolator comprising a control unit for controlling a driving force. 2. The control means increases a driving force for one of the plurality of actuators in which the load acting on the actuator increases due to the load movement of the device, and drives the one in the plurality of actuators for which the acting load decreases. 2. The vibration isolator according to claim 1, wherein the vibration is reduced so as to reduce the force. 3. An anti-vibration table mounted with a device that generates a load movement and supported so as to be able to move up and down, and a plurality of actuators for applying an upward driving force to the anti-vibration table. In the vibration damping device, a driving force is increased with respect to a device in which the load acting on the actuator is increased by the load movement of the device so as to offset a variation in the load applied to the plurality of actuators caused by the load movement of the device. And controlling each of the plurality of actuators so as to reduce the driving force in response to a reduction in the applied load.