JPH06147256A - Control method for vibration eliminating mount - Google Patents

Abstract

PURPOSE:To perform rapid positive damping by computing and inferring a coordinate position to be moved by means of signals from three or more vibration sensors through vibration of each of the vibration eliminating mount supporting points of four or more positive actuators, and controlling a damping amount of each actuator. CONSTITUTION:Vertical movement amounts of the support points A-C of a vibration eliminating mount 2 owing to a load W are detected by means of a level sensor 9, a level voltage therefrom is compared with a reference level voltage, and a displacement amount is computed. Control valves 6b at the support points A-C are controlled, and compressed air is fed to an air spring 3e to raise the vibration eliminating mount 2. At a support point D at which there is no level sensor 9, an amount to be moved of the support point D is computed and inferred by means of signals from three level sensors 9 and a control amount of the air spring 3e is decided. When the vibration eliminating mount 2 is raised and an output voltage from the level sensor 9 is adjusted to a value equal to a reference level voltage, the vibration eliminating mount 2 is horizontally maintained at a reference level. When the vibration eliminating mount 2 is floated up to a level higher than the reference level, operation is reversed. This constitution causes prevention of the occurrence of interference and execution of rational control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method of controlling an active actuator for vibration isolation mounted on a main body of a vibration isolation table.

[0002]

2. Description of the Related Art At present, the precision of a manufacturing apparatus mounted and used on a vibration isolation table is dramatically improved. However, it has been required to significantly improve its vibration damping ability.

Therefore, as an epoch-making method for improving the performance of the vibration isolation table, the vibration input to the vibration isolation table is sensed, and this is detected as CP.
A technique of active vibration control has been newly introduced, in which a U or the like instantly performs arithmetic processing to control the vibration control amount of the actuator.

Now, the vibration isolation table main body is generally in the shape of a rectangular platform, and active actuators (A) to (D) composed of air springs and the like are arranged at each of the four corners thereof. It supports the shaking table body (2). And, in order to output the vibration component in the horizontal and vertical directions as an electric signal for damping in any direction such as the vertical direction of the vibration isolation table main body (2), the horizontal direction or the rotation direction, the sensor (Sa) ( Sb) and (Sc) are arranged in each of the active actuators (A) to (D). The sensors (Sa) (Sb) (Sc) control the corresponding active actuators (A) to (C), and the remaining one active actuator (D) is the sensor (Sa) of the adjacent active actuator (A). ) Is controlled by receiving the signal from. Thereby, the sensors (Sa) (Sb) (Sc) control all the active actuators (A) to (D).

The active actuators (A) to (D) are concepts including the horizontal direction active actuators (A1) to (D1) and the vertical direction active actuators (A2) to (D2), and the sensor (S
a) (Sb) (Sc) ... means a group of sensors attached to the active actuators (A) to (D). Position sensors (1a) (1b) (1c) for detecting horizontal position displacement, vertical acceleration Sensor (10a) (10b) (1
0c), horizontal direction acceleration sensor (11a) (11b) (11c), and level sensor (9a) (9b) (9c) concept, when only level sensing is performed, when only horizontal position displacement is detected There are cases in which only vertical vibrations are controlled, only horizontal vibrations are controlled, and a combination of all of these is controlled. In each case, a sensor is used in combination. The alphabets represent the correspondence between actuators and sensors. In addition, the symbols of the support points of the vibration isolation table main body (2) supported by the active actuators (A) to (D) are the same as those of the active actuator (A) for convenience.
Use ~ (D).

The conventional control method will be described taking the case of only level control as an example. One level sensor (9a) controls two adjacent active actuators (A) and (D), and the remaining two actuators are controlled. The active actuators (B) and (C) are controlled by the level sensors (9b) and (9c) installed on a one-to-one basis with them. The two active actuators (A) (D) controlled by one level sensor (9a) are the horizontal lines connecting the two active actuators (A) (D) in order to perform the same control.
It is controlled as (L ''). On the other hand, the active actuators (B) and (C), in which the sensor and the active actuator have a one-to-one correspondence, are individually level sensors (9b).
It will be controlled by (9c), and the plane (A'B'C'D '') including the horizontal line (L '') and these two points is originally the position (D) where the point (D) should be ( The active actuator (D) will control so that it will be located at a position (D '') that is displaced by (Δdp) from (D '), and the original control plane (A'B'C'D' (I.e., it becomes a distorted surface with respect to the control plane in the present invention) (in other words, the active actuator (D) is required to make a displacement correction larger than necessary), and as a result, the vibration isolation table body There is a problem in that the movements of the active actuators (A) to (D) that suppress the vibration input to (2) interfere with each other and it takes time to set the level.

Therefore, four active actuators (A)
It was considered that the sensors (S) were attached to all of (D) and the active actuators (A) to (D) were controlled independently, but as described above, firstly, the sensor (S) Not only the number of active controllers (A) to (D) and the control circuit (cont) become too complicated due to too many numbers, but also the cost becomes too high. Secondly, four active actuators ( When controlling A) to (D) independently, 4 active actuators (A)
It is extremely difficult to control ~ (D) to return to the reference level (H ₀ ) in the same plane at the same time, and even in this case, each active actuator (A) ~ (D) interferes with each other. The underlying problem was that the damping effect would be impaired in some cases.

[0008]

The problems to be solved by the present invention are as follows.
The purpose is to rationally control four or more active actuators with three or more sensors for vibration detection without interfering with each other to achieve quick active vibration control.

[0009]

A method of controlling an anti-vibration table according to the present invention is described as "4 or more active actuators (A) to (D) mounted for vibration control of the anti-vibration table main body (2). ) And 3 arranged to control the active actuators (A) to (D)
Sensors (Sa) (Sb) (Sc) for detecting more than one vibration and signals from the sensors (Sa) (Sb) (Sc) are fetched and calculated, and input to the vibration isolation table body (2) from the outside. Control circuit (cont) for controlling the active actuators (A) to (D) so as to suppress the vibration
In the vibration isolation table configured with, the sensor (Sa) (Sb) (S
the active actuator (A) by capturing the signal from c)
~ (D) Coordinate positions (A ') ~ (D') to be moved by vibration of each of the vibration isolator support points are calculated and inferred, and active actuators (A) ~ (D) are calculated based on these calculated values. Each of the vibration isolation table main body support points controls the amount of damping of each active actuator (A)-(D) so that the vibration isolation table main body (2) returns to the origin position where the vibration isolation table main body (2) stabilizes. It is what As a result, all the active actuators (A) to (D) can be rationally controlled without interfering with each other, and quick active vibration control can be achieved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. The vibration isolation table consists of a vibration isolation table main body (2), which is a surface plate part for mounting manufacturing equipment such as holography set, electron microscope, ultra-precision measuring equipment such as semiconductor manufacturing equipment, and vibration isolation table main body (2). Four active actuator sets (A) to (D), a sensor (S) group, and the active actuator set (A) to be arranged at four corners of the vibration isolation table main body (2) for supporting.
(D) and a control circuit (cont) for active control.

The active actuator sets (A) to (D) described in this embodiment are blocks in which vertical active actuators (A2) to (D2) and horizontal active actuators (A1) to (D1) are integrally incorporated. It is a shape. Of course, vertical active actuator (A2) ~ (D2) and horizontal active actuator (A1) ~
You may use the unipotential type active actuator which separated (D1) separately. The active actuator sets (A) to (D) are arranged in a wind turbine type so that the horizontal control directions of the adjacent active actuator sets (A) to (D) are perpendicular to each other as shown in FIG. It has been done.

Active actuator set according to the present invention
(A) to (D) include those using an air spring, those using a piezo element, and those using a linear motor. Hereinafter, the case where air springs are used as the vertical active actuators (A2) to (D2) and the horizontal active actuators (A1) to (D1) will be mainly described. Further, the vertical support (7) uses a laminated body in which rubber plates and metal plates are alternately laminated, and the vibration isolation table main body (2) and the horizontal active actuators (A1) to (D1) are used. The case where a wire is used for the horizontal support (8) connected to each is mainly described.

In FIGS. 2 and 3, the active actuator sets (A) to (D) are vertically and horizontally two-way control.
(Of course, one active actuator may be controlled in three axes in vertical and two horizontal directions.) Active actuator set (A) "The same applies to other active actuators. Is composed of a vertical air spring (3e), a vertical support (7), a pair of horizontal air springs (3a) (3b), sensors (Sa) attached to each of them, and the like.
Position sensors (1a) (1b) (1c) and level sensors (9a) (9b) (9c) use non-contact analog output type proximity sensors, and vibration control uses acceleration sensors. There is.

Vertical air spring (3e) and horizontal air spring (3a)
Each of (3b) has a known structure including a rubber spring portion (5) and an air tank (4) communicating with the rubber spring portion (5).

Air tank (4) for horizontal air springs (3a) (3b)
Are independently arranged on the left and right sides through a central partition plate (26 '). In this embodiment, the horizontal air springs (3a) (3b) have a control side and a reference side, and the reference side horizontal air spring (3a) has a constant pressure air source via a precise regulator (19). (1
It is connected to 6).

On the other hand, the control side horizontal air spring (3b) is a control valve.
The air pressure source (16) is connected via (6a), and the control valve (6a) is controlled by a vibration isolation circuit (cont) described later. (Of course, using the reversing device, the reference side horizontal air spring (3a)
In addition, the control signal input to the control side air spring (3b) may be inverted to input the signal, and in this case, push-pull control is performed. )

As can be seen in FIG. 2, the horizontal air spring (3a)
(3b) is surrounded by the casing (30),
The thin line member (8) connects the (30) and the vibration isolation table body (2).

The vertical air spring (3e) is mounted on a vertical support (7) mounted on a fixed base (25).

The active actuators (A) to (D) assembled as described above are used by being attached to the four corners of the base (28) as shown in FIG. As shown by arrows (A1) to (D1) in FIG. 1, the mounting directions are arranged in a wind turbine type so that the expansion and contraction control directions of the adjacent horizontal air springs (3a) and (3b) are orthogonal to each other.

In the present invention, (1) active control in the case where the centers of the active actuators (A) to (D) and the mounting positions of the sensors (S) coincide with each other, (2) the active actuator ( A)
There are two possible cases: active control when the center of (D) and the mounting position of sensors (S) do not match, but here is the simplest case (1) where only level control is performed. The control method of the present invention will be described by taking a typical example.

As can be seen from FIG. 4, a reference level voltage corresponding to the reference level (H ₀ ) of the vibration isolation table main body (2) is input to the control circuit (cont). 2) When the load (W) is applied on top and the vibration isolation table body (2) sinks, on the contrary, when the vibration isolation table body (2) rises due to unloading, or when the load moves, the vibration isolation table When the main body (2) is tilted, the vertical movement amount (d ₁ ) to (d ₃ ) of each supporting point (A) to (C) relative to the reference level (H ₀ ) (see FIG. 17) It is detected by each level sensor (9a) (9b) (9c) and output as each level voltage, and the control circuit (c
ont) and is compared with the reference level voltage. An operation for adding the difference in an integral and proportional manner (that is, PI control)
Then, the amount of displacement in each of the level sensors (9a) (9b) (9c) is immediately calculated. Then, each control valve (6b) is controlled so as to correspond to this output value. The control valves (6b) are respectively connected to the air tanks (4) of the air springs (3e) for maintaining the levels of the active actuators (A2) to (C2). The control valve (6b) is, for example, a servo valve,
Air spring (3e) for maintaining the level by precisely controlling the valve opening
It has the ability to accurately control the pressure in the air tank (4).

As a result, the control valve (6b) at the support points (A) to (C) is controlled by the output value from the control circuit (cont), and compressed air is supplied to the air tank (4) of the air spring (3e). And lift the vibration isolation table body (2). In the air spring (3e) at the support point (D) where the level sensor (9) is not attached, the output of the adjacent level sensor (9a) is used as it is, but in the present invention, three level sensors are used. (9a) (9b) (9c) signal is taken in and the level sensor (9) is not mounted
Instantaneous calculation and inference of the amount of movement of (D), and a support point where the level sensor (9) is not attached by this inference value
The control amount of the air spring (3e) of (D) is determined. The calculation method is an ordinary mathematical method.

When the four active actuators (A2) to (D2) are operated by being controlled by the output values individually given from the control circuit (cont), the vibration isolation table main body (2) begins to lift, and As a result, the output voltage of each level sensor (9a) (9b) (9c) gradually increases, gradually approaching the reference level voltage (H ₀ ), and finally the level sensors (9a) (9b) (9c) almost simultaneously. It becomes equal to the level voltage (H ₀ ), and the difference between the two becomes zero. The input value to the control valve (6b) is stable at this point, and the vibration isolation table body (2) is stably maintained at the horizontal position corresponding to the reference level (H ₀ ). When the main body (2) of the vibration isolation table is lifted above the reference level (H ₀ ), the reverse operation to the above is performed.

In the above cases, the active actuator (A2)
(C2) Air spring (3e) support points (A) to (C) and level sensor (9
a) (9b) (9c) and the installation position is the same,
Level sensor (9a) (9b) (9c) displacement detection amount and vibration isolation table body
Although it corresponds to the amount of displacement of the support points (A) to (C) of (2), the support points (A) to (A) of the air springs (3e) of the active actuators (A2) to (C2)
If (C) and the installation positions of the level sensors (9a) (9b) (9c) do not match, the two do not match. Therefore, in the case of such a mismatch, the signals from the level sensors (9a) (9b) (9c) are taken into the control circuit (cont), and the level sensors (9a) (9b) (9
c) and the corresponding active actuators (A2) to (C2) are calculated by considering the amount of deviation of the mounting position from the center of gravity (G), and the active actuator (A2) to (C2) vibration isolator support points
Coordinate position (A ') to be moved by vibration of each of (A) to (C)
~ (C ') is calculated and inferred in consideration of the deviation amount, and based on the calculated value, each of the vibration isolation table main body supporting points (A) to (C) of the active actuators (A2) to (C2) However, the damping amounts of the respective active actuators (A2) to (C2) are controlled so that the vibration isolation table main body (2) returns to the stable origin position.

In the air spring (3e) at the supporting point (D) where the level sensor (9) is not mounted, the three level sensors (9a) (9b) (9c) are connected as in the first embodiment. The signal is taken in and the amount of movement of the support point (D) to which the level sensor (9) is not attached is instantly calculated and inferred in consideration of the amount of deviation, and the level sensor (9) is inferred by this inference value. The control amount of the air spring (3e) of the support point (D) which is not attached is determined. The calculation method is an ordinary mathematical method.

In the above case, only the level control is described as an example, but the same applies to the case of horizontal position variation, and four active actuators (A1) to (D1) arranged in a wind turbine type are used. ), The three horizontal position displacement detection sensors (1) are controlled to return the vibration isolation table main body (2) to its original position. In Fig. 4, (6a) is a horizontal active actuator (A
This is the control valve of 1).

Further, it is of course possible to simultaneously perform the level control, the horizontal position control and the acceleration detection. Even in this case, the level sensors (9a) (9b) (9c) and the horizontal position detection sensor (1a) ) (1b) (1c), vertical and horizontal acceleration sensors (10a) (10b) (10c), (11a) (11b) (11c), etc.
(Sa) (Sb) (Sc) by capturing the signal from the active actuator (A) ~ (D) of each of the vibration isolation table main body support points, coordinate position (A ') ~ (D to move by vibration ') Is calculated and inferred based on this calculated value so that each of the vibration isolation table main body support points of the active actuators (A) to (D) returns to the origin position where the vibration isolation table main body (2) stabilizes. Each active actuator (A) ~ (D)
Will control the amount of vibration suppression.

13 to 16 show an example of control by the conventional method, FIG.
In the present invention, as shown in (1), 8 to 8 show the results of active control under the assumption that the centers of the active actuators (A) to (D) and the mounting positions of the sensors (S) are aligned. 9 to 12 are graphs showing the present invention, and in the present invention, as shown in (2), the centers of the active actuators (A) to (D) and the sensors
It is a graph showing the result of active control when the mounting position of (S) does not match. Figure 4 is a schematic front view of the experimental device, 35 kg.
The load (W) was set on the moving stage (St), and the level settling state was observed when the load was moved by 20 mm. FIG. 1 shows the moving directions (X1) to (X4) of the moving stage (St). (D ₁ ), (d ₂ ), and (d ₃ ) shown in FIG. 17 indicate minute displacements detected by the level sensors (9a) (9b) (9c). 5 to 16, the horizontal axis indicates the moving direction, and the two squares indicate the moving amount of 20 mm. Therefore, the movement is measured 20 mm × 4 times. The vertical axis represents the output value from the control circuit (cont). Comparing FIGS. 5 to 16, it can be seen that the levels of the methods (1) and (2) of the present invention are settled more quickly than the conventional method.

Finally, an example of calculation in the present invention will be shown. The horizontal, vertical and rotational components of the vibration of the vibration isolation table main body (2) are controlled by the three horizontal sensors and the three sensors as described above.
It can be measured with two vertical sensors. This means that it is possible to calculate the fluctuation of any position described by the coordinates of the rigid system.

The anti-vibration table main body (2) controls the horizontal and vertical directions by 8 (= 4 × 2) active actuators and 6 active actuators.
(= 3 × 2) sensor. At this time, if it is attempted to obtain the amount of fluctuation of the support points (A) to (D) of the active actuator with six sensors, dU = E · dS '... (1) where dS' is the dS Transposition dS can be written as the detection amount of the sensor, and dU can be written as the variation amount of the supporting points (A) to (D) of the active actuator. Also, E is a mathematical formula

[Equation 1] as well as

[Equation 2] Is asked for.

In particular,

From [Equation 2], it is possible to obtain a simple input method of the variation amount (U4) of the support point (D) of the vertical active actuator and the variation amount (U8) of the support point of the horizontal active actuator with no sensor attached. . dS = [dS1, dS2, dS3,
dS4, dS5, dS6], dU4 = dS1 + dS2-dS3 ……………… (2) Equation dU8 = (L / W) dS4 + dS5− (L / W) dS6 ………… (3) Equation

The equations (2) and (3) show that it is possible to generate a control signal for a vertical actuator having no sensor by adding and subtracting each sensor using only the sensor in the vertical direction.

A signal of the amount of fluctuation (U8) of the supporting point of the horizontal active actuator to which no sensor is attached can also be generated by using the horizontal sensor. At this time, some coefficient calculation is involved, but a simple analog amplifier can sufficiently cope with this.

From the above, it is possible to obtain a control signal generation rule that can be applied to a large number of active actuators by an analog amplifier by limiting the arrangement of the sensors and the arrangement of the active actuators described later.

The results using the control signals thus generated are very useful as shown in the experimental data.
Practically, even if the arrangement is loose, the effect is sufficient. For example, the shape does not have to be strictly rectangular, and even if (e) is slightly different, a sufficient effect can be achieved as compared with the conventional method.

[0036]

[Equation 1]

[0037]

[Equation 2]

Limitation in (Equation 1) Equation 1 is a case where the height of the sensor is adjusted to the active actuator, and the sensor is arranged so as to be shifted by (e) in the wind turbine type. However, Lp2 = L + 2e, Lp1 = L + e, Wp2 = W
+ 2e, Wp1 = W + e Ls2 = L-2e, Ls1 = L + e, Ws2 = W-2e,
Ws1 = W−e L, W = distance between active actuators e = distance between active actuator and sensor

Limitation in (Equation 2) When the position of the sensor and the active actuator are so close to each other that they can be ignored. It is obtained by substituting (e = 0) into Equation 1.

[0040]

Since the present invention has the above-mentioned structure,
It was possible to rationally control four or more active actuators with three or more vibration detection sensors without interfering with each other, and achieve quick active vibration control.

[Brief description of drawings]

FIG. 1 is a layout plan view of an active actuator according to the present invention.

FIG. 2 is a plan sectional view of an active actuator according to one embodiment of the present invention.

FIG. 3 is a vertical sectional view of an active actuator according to an embodiment of the present invention.

FIG. 4 is a block circuit diagram of one embodiment of the circuit of the present invention.

FIG. 5: X1 → X2 in the control method (1) of the present invention
Position when the moving stage moves by 20mm
Graph showing the output value of the control circuit based on the signal from the level sensor installed in (A) ~ (C)

FIG. 6 shows X2 → X1 in the control method (1) of the present invention.
Position when the moving stage moves by 20mm
Graph showing the output value of the control circuit based on the signal from the level sensor installed in (A) ~ (C)

FIG. 7: X3 → X4 in the control method (1) in the present invention
Position when the moving stage moves by 20mm
Graph showing the output value of the control circuit based on the signal from the level sensor installed in (A) ~ (C)

FIG. 8: X4 → X3 in the control method (1) of the present invention
Position when the moving stage moves by 20mm
Graph showing the output value of the control circuit based on the signal from the level sensor installed in (A) ~ (C)

FIG. 9 is a signal from the level sensor installed at positions (A) to (C) when the moving stage moves by 20 mm from X1 to X2 in the experimental example in the control method (2) of the present invention. Graph showing the output value of the control circuit based on

FIG. 10 is a signal from the level sensor installed at positions (A) to (C) when the moving stage is moved by 20 mm from X2 to X1 in the experimental example in the control method (2) of the present invention. Graph showing the output value of the control circuit based on

FIG. 11 is a signal from a level sensor installed at positions (A) to (C) when the moving stage is moved by 20 mm from X3 to X4 in the experimental example in the control method (2) of the present invention. Graph showing the output value of the control circuit based on

FIG. 12 is a signal from the level sensor installed at positions (A) to (C) when the moving stage moves by 20 mm from X4 to X3 in the experimental example in the control method (2) of the present invention. Graph showing the output value of the control circuit based on

FIG. 13: The moving stage is 20 from X1 to X2 in the conventional example.
Graph showing the output value of the control circuit based on the signal from the level sensor installed at the positions (A) to (C) when moving by mm.

[Fig.14] The moving stage is 20 m from X2 to X1 in the conventional example
Graph showing the output value of the control circuit based on the signal from the level sensor installed at positions (A) to (C) when moving by m

FIG. 15: The moving stage moves from X3 to X4 in the conventional example
Graph showing the output value of the control circuit based on the signal from the level sensor installed at the positions (A) to (C) when moving by mm.

FIG. 16: The moving stage moves from X4 to X3 in the conventional example
Graph showing the output value of the control circuit based on the signal from the level sensor installed at the positions (A) to (C) when moving by mm.

FIG. 17 is a perspective view when comparing the displacement amounts of the control method (1) of the present invention and the control method of the conventional example.

FIG. 18 is a perspective view for explaining a calculation method according to the present invention.

FIG. 19 is a plan view for explaining a calculation method according to the present invention.

[Explanation of symbols]

(A)… Horizontal vibration isolation device (A1)… Horizontal active actuator (A2)… Vertical active actuator (H ₀ )… Reference level (S ₀ )… Reference horizontal position (1)… Position sensor (2)… Exclude Shaking table body (3a) ... Horizontal reference side air spring (3b) ... Horizontal control side air spring (3e) ... Vertical air spring (4) ... Air tank (5) ... Rubber spring parts (6a) (6b) )… Control valve (7)… Laminate (8)… Wire (9)… Level sensor (10)… Vertical acceleration sensor (11)… Horizontal acceleration sensor (16)… Pneumatic pressure source (19)… Regulator ( 25)… Fixed base (26 ')… Partition plate (28)… Base (30)… Casing

Claims (1)

[Claims] 1. A four or more active actuators mounted for vibration control of a vibration isolation table main body, three or more vibration detection sensors arranged for controlling the active actuator, and the sensor. In the vibration isolation table configured with a control circuit for controlling the active actuator so as to suppress the vibration input from the outside to the vibration isolation table main body, the signal from the sensor is captured. The coordinate position of each of the vibration isolation table main body supporting points of the active actuator to be moved by vibration is calculated and inferred, and each of the vibration isolation table main body supporting points of the active actuator stabilizes the vibration isolation table main body based on the calculated value. A method for controlling an anti-vibration table, characterized in that the damping amount of each active actuator is controlled so as to return to the origin position.