JP2864038B2 - Microvibration test method and device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an epoch-making precision microvibration test apparatus capable of performing tests for various vibrations with almost no influence of disturbance vibration.

(Conventional technology and its problems) Various vibrations such as strong vibration, weak vibration, various frequencies from high frequency to low frequency, horizontal vibration, vertical vibration, etc. are transmitted to the floor and installed on the test machine stand The above-mentioned miscellaneous vibrations are also transmitted to the installed device from the floor surface. Also, there is disturbance due to compression waves from the surrounding air, and vibrations are generated from the equipment itself.

Conventional vibration test equipment fixes a precision device to be tested on a test machine table for vibration, and then inputs test vibrations to the test machine table to vibrate the precision device to perform a vibration test. I was going.

However, as described above, since the disturbance vibration and the vibration at the time of the operation of the device under test are constantly input to the test machine table, the test vibration is not affected by the disturbance vibration or the operation vibration (hereinafter simply referred to as disturbance vibration, etc.). When the test vibration is very large, the influence of the disturbance vibration on the test result is small.However, when the test vibration is small, the test result is extremely inaccurate due to the influence of the disturbance vibration. In addition, it was impossible to test disturbance vibrations or minute vibrations below the disturbance vibrations.

(Object of the present invention) The present invention has been made in view of the drawbacks of the conventional example, and the object thereof is to input a control force for controlling disturbance vibration and the like to a test machine stand to offset the control force to some extent. Another object of the present invention is to provide a microvibration test method and a microvibration test method capable of performing a vibration test of almost pure test vibration only by inputting a test vibration.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides, as set forth in claim (1): a vertically disturbing vibration of a test machine stand (2) by expanding and contracting vertically. A vertical actuator (A ₂ ) that almost cancels G) and vibrates the vertical test vibration (T), and is connected to the test machine stand (2), and expands and contracts in the horizontal direction, and the test machine stand (2) A horizontal actuator (A ₁ ) for substantially canceling the horizontal disturbance vibration (G) and exciting the horizontal test vibration (T), and the operating vibration of the disturbance source of the test machine stand (2) or the test machine A vertical disturbance vibration (G) input to the table (2) is detected, and a control signal for generating a control force based on the disturbance vibration or the operation vibration is transmitted to the vertical actuator (A).
₂ ) A vertical vibration damping circuit (B ₂ ) that feeds back and / or feeds forward, and operates a vibration source of a disturbance source of the test stand (2) or a horizontal disturbance vibration input to the test stand (2). A horizontal vibration damping circuit (B ₁ ) that detects and feeds back and / or feeds back a control signal for generating a control force based on the disturbance vibration or the operation vibration to the horizontal actuator (A ₁ ); A practical three-dimensional six-degree-of-freedom micro-vibration test device composed of a test vibration input device (C) for inputting a test vibration (T) to each of the directional actuator (A ₂ ) and the horizontal actuator (A ₁ ) Is provided.

(Operation) In the above-described configuration, the micro-vibration test is started after the precision equipment to be tested is installed and fixed on the test machine stand (2). First, the input disturbance vibration (G) is set as the vibration acceleration. It is detected by the acceleration sensors (10) and (11) of the vibration suppression circuit (B), and for example, the disturbance vibration acceleration is differentiated, proportional, or /
And multiplying the multiplied value by a coefficient. The multiplied value is fed back to the actuator (A) to obtain the disturbance vibration (G).
On the other hand, the control force (F) for controlling this is input to the test machine stand (2) with almost no delay to substantially cancel the disturbance vibration (G) and minimize the influence of the disturbance (G). At the same time, the necessary test vibration (T) is input to the test stand (2), and a vibration test using only the test vibration (T) is performed.
Also, so-called feed-forward control is performed in which the disturbance vibration (G) or the like is patterned in advance and a control force patterned in accordance with the input of the disturbance vibration (G) or the like.
This enables a precise vibration test that is hardly affected by the disturbance (G) and a microvibration test that is about the same as or less than the disturbance (G).

(Examples) Hereinafter, the present invention will be described in detail with reference to illustrated examples.

The microvibration test apparatus according to the present invention substantially cancels out the disturbance vibration (G) input to the test machine stand (2) and the test machine stand (2) and excites the test vibration (T). And a control force (F) for detecting disturbance vibration (G) of the test machine stand (2) and for substantially canceling the disturbance vibration (G) and the like.
(B) and actuator (A)
And a test vibration input device (C) for inputting a test vibration (T) to the device.

The testing machine base (2) is a platen-shaped one as shown in FIGS. 4 and 5, and has an upper surface on which an ultra-precision device such as an electron microscope and a semiconductor manufacturing device is mounted and fixed.

The number of actuators (A) may be one in the case of one dimension, but in the case of three-dimensional control, it is composed of three to four vertical actuators (A ₂ ) and three to four horizontal actuators (A ₁ ). Will be done. (Of course, a two-dimensional case is also possible in some cases.) In this embodiment, a case of three-dimensional and six degrees of freedom will be described as an example. There are various actuators (A) such as a system using an air spring, a system using a piezo element, and a system using a linear motor. In this embodiment, the case of air spring control is mainly described. However, the method is not limited to the air spring control method, and is not limited to the piezo element method or the linear motor method. Further, these may be appropriately combined according to the characteristics. The control method also differentiates, proportionally and integrates the detected vibration acceleration.
A description will be given focusing on PID control, but there are other various control methods, and the present invention is not limited to the embodiment.

When the vibration suppression circuit (B) also has three-dimensional six degrees of freedom, the vertical vibration suppression circuit (B ₂ ) and the horizontal vibration suppression circuit (B ₁ ) control the actuators (A ₁ ) and (A ₂ ), respectively. ) Is installed.

The test vibration input device (C) is a device for inputting a signal to be tested to the actuator (A), and is usually built in the CPU. The test waveform is generated by being fetched from an external device or generated inside the CPU. The waveform can be reproduced in a wide frequency band by using the vibration characteristics of the test stand (2) as an inverse filter. Alternatively, a more accurate test waveform can be generated by using a region having a flat phase as the excitation control region as shown in FIGS.

The test stand (2) is supported by the vertical support (7) via the vertical actuator (A ₂ ).
The vertical support (7) moves almost freely with respect to the horizontal direction, but is hardly compressed in the vertical direction.

 Hereinafter, each component block will be described in detail.

First, the air spring type actuator (A) according to the present invention will be described. The air spring type actuator (A) includes a vertical air spring (3c), a support (7) and a pair of horizontal air springs (3a) (3b) [(3) (3 ')], a vertical acceleration sensor (10). ), And a horizontal acceleration sensor (11). Both the vertical air spring (3c) and the horizontal air springs (3a) (3b) [(3) (3 ')] communicate with the rubber spring part (5) if necessary due to the relationship with the spring constant. And an air tank (4). The entire circumference of the rubber spring portion (5) is tightly bolted to the standing plate (25) to the partition plate (26) to which the air tank (4) is attached by a ring-shaped fixing seat (24). A circular washer (27) having a trapezoidal cross section is fitted into the central movable part. Horizontal air spring (3a) (3b) [(3)
(3 ')] air tank (4)
6 ') are arranged independently on the left and right. In this embodiment, the horizontal air springs (3a) and (3b) have a control side and a reference side. The reference side horizontal air spring (3a) has a constant pressure pneumatic source through a precision regulator (19). Connected to (16). On the other hand, the control side air spring (3b) is connected to the control valve (1
The air pressure source (16) is connected via 4), and the control valve (14) is controlled by a vibration suppression feedback circuit (B ₁ ) (B ₂ ) described later. As can be seen from FIG. 2, the horizontal air springs (3a) and (3b) are surrounded by a casing (30), and both circular washers (27) are attached to the casing (30).
Is fixed to the inner surface of the. In this embodiment, the casing (30) and the test stand (2) are connected by a thin wire (8) [or a laminate (not shown, but having the same structure as a support (7) described later)]. I have. As shown by the solid line in FIG. 2, the connecting method is such that the arm (29) is protruded from the outer surface of the casing (30), and the wire (8) is stretched between the side walls (2a) of the test machine stand (2). The arm (29) may be fixed, or a wire (8) projecting from the center of the casing (30) may be fixed to the side wall (2a) of the test machine stand (2) as shown by a virtual line. Is also good.

The vertical air spring (3c) is mounted on a support (7) mounted on an upright plate (25). The support (7) is, for example, a laminate in which a rubber plate (31) and a metal plate (32) are laminated in multiple layers, and moves almost freely in the horizontal direction but hardly compresses in the vertical direction. have. In this embodiment, the support (7) is used in two stages.

In this embodiment, the air spring actuator (A) assembled as described above is mounted and used at four corners of the base (28) as shown in FIG. As shown by the arrow in FIG. 1, the mounting direction is such that the expansion and contraction directions of the adjacent horizontal air springs (3a) and (3b) are orthogonal to each other. (Not shown, the air spring actuator (A) is used as a base (28)
May be used by attaching to the three corners.

The piezo element system utilizes a phenomenon in which the piezo element expands and contracts in proportion to the input voltage. The linear motor system utilizes the Fleming's left-hand rule. Similarly, the carrier (shown in FIG. Is a method that utilizes the movement of The control method is not limited to this, but may be any method that can achieve the above functions.

Next, the control circuit (B) will be described. A horizontal acceleration sensor (11) is attached to the arm (29) of the air spring actuator (A) that moves back and forth, right and left, and rotates together with the test machine stand (2).

First, a description will be given of the vibration suppression of the minute horizontal vibration of the minute vibration test apparatus. The horizontal vibration is transmitted from the floor surface or the surrounding air, and when the equipment operates or generates vibration, the test machine stand (2) shakes. The horizontal acceleration detecting the horizontal vibration acceleration () A sensor (11) is provided for each of the air spring actuators (A) (four locations in this embodiment), and a horizontal vibration integration amplifier (20a) for integrating the output of the horizontal acceleration sensor (11). A horizontal vibration differential amplifier (21a) for differentiating the output and a horizontal vibration proportional amplifier (22a) for amplifying the output are provided.

Here, the combination of these amplifiers will be described as follows, but as a practical combination, the combination differs depending on the type of the actuator (A).

 Hereinafter, combinations of amplifiers will be described.

Horizontal vibration integration amplifier (20a) only, horizontal vibration differentiation amplifier (21a) only, horizontal vibration proportional amplifier (22a) only, combination of horizontal vibration integration amplifier (20a) and horizontal vibration differentiation amplifier (21a), Combination of horizontal vibration integral amplifier (20a) and horizontal vibration proportional amplifier (22a), Combination of horizontal vibration differential amplifier (21a) and horizontal vibration proportional amplifier (22a), Horizontal vibration integral amplifier (20a) and horizontal Directional vibration differential amplifier (21a) and horizontal vibration proportional amplifier (22a)
There are combinations.

Outputs from these amplifiers are input to a horizontal drive circuit (17) together with an electric signal of a test vibration (T) to be described later, and are input to a control valve (14) to adjust a valve opening, and a control side air spring ( Adjust the pressure in the air tank (4) in 3b).

Here, when the function of each amplifier, the horizontal direction vibration integrating amplifier (20a) integrates the horizontal acceleration () and ₃ times K, outputs the converted velocity component (K ₃ · 1 / S) to control the absolute displacement of the test stand (2) at that position regardless of the position of the test stand (2),
In other words, it functions to absorb the micro vibration and eliminate the vibration of the micro vibration test apparatus. In terms of the spring characteristics, it performs the same function as the “hardening the spring” function, and is particularly effective for low frequency control.

Horizontal direction vibration proportional amplifier (22a) is for amplifying the horizontal acceleration () to K ₄ times, control side air spring (3
It serves to increase the damping efficiency (b) in the resonance region.

Acts horizontal direction vibration differentiating amplifier (21a), the horizontal acceleration () K ₅ multiplies, which corresponds to the case where increasing the mass of the differential to the output (K ₅ · S) was intended, tester board (2) And contributes to the damping effect especially in the high frequency range.

By using the above amplifiers in combination, the minute vibration is controlled according to the characteristics of the amplifiers.

Controlling the flow rate by controlling the valve opening with the control valve (14) and controlling the pressure of the control-side air spring (3b) is equivalent to integrating the flow rate as described above.

With the above PID control, even if disturbance vibration (G) of any frequency from low frequency to high frequency is transmitted from the floor surface or ambient air to the test machine stand (2), the horizontal acceleration The horizontal acceleration () is detected by the sensor (11), and this is used as a test vibration input device (C) for the CPU.
Is input to the subtractor (34a), the inverted signal of the horizontal acceleration () and the test vibration (T) component are added, and the added value is used as the described amplifiers (20a) (21a) ( twenty two
a), the calculated value, the vibration and vibration (T), and the proportional or fine / integral value, the phase compensation, or the addition thereof are calculated according to the characteristics of the object to be controlled. T × K (S)} is input to the adder (35a) and added, and the added value is input to the control valve (14) to substantially cancel the disturbance vibration and to purely apply only the test vibration (T) to the actuator. (3b). << FIG. 4 (b) >> As shown in FIG. 4 (a), the horizontal acceleration () is input to the subtractor (34a) and the test vibration (T) from the test vibration input device (C) of the CPU is input. ) Is input to the subtractor (34a), the test vibration (T) component is added to the inversion signal of the horizontal acceleration (), and the result is integrated. The integrated value and the described amplifiers (21a) (2
The proportional value and differential value processed in 2a) are added and input to the horizontal drive circuit (17), which is input to the control valve (14) to adjust the valve opening, and the control side air spring (3b ) Adjust the pressure in the air tank <4).

This relationship is the same in the vertical direction, and a description thereof will be omitted.

Further, a coil spring may be used instead of the reference-side control-side air spring (3a) so that the response is improved and active damping can be performed even in a high-frequency range. Without distinction, a pair of air springs (3) as shown in FIG.
(3 ') A control signal whose phase is inverted by 180 ° may be input to each of them, and the two air springs (3) and (3') may be controlled in the same direction to double the damping force. In addition, (3
3) inverts the output of one adder (35a) to control valve (1
This is a phase inverter for input to 4).

Here, since the casing (30) and the side wall (2a) of the test machine stand (2) are connected by the wire (8), the vibration in the direction parallel to the wire (8) is transmitted through the wire (8). Vibrations that are not parallel to the wire (8) will be transmitted to the horizontal air springs (3a) (3b) [(3) (3 ')] from the floor because the wire (8) bends, although it will be canceled. The horizontal and vertical vibrations are cut off at the wire (8) and are not transmitted to the test stand (2). Therefore, the horizontal vibration in the control direction is almost completely canceled, and at the same time, the vibration other than in the control direction is cut off at the wire (8), and the air spring actuator (A) does not act as a medium for transmitting the vibration.

Next, vibration suppression of minute vertical vibration will be described. A vertical component acceleration sensor (10) for detecting a vertical vibration acceleration () of the test machine stand (2) is disposed at a portion that vibrates together with the test machine stand (2) of the air spring actuator (A). Output () of this vertical component acceleration sensor (10)
Vertical oscillation integral amplifier (20b) that integrates and multiplies K ₈ times,
One of the vertical vibration proportional amplifier (22c) for amplifying or two or more are equipped said output differentiation to K ₁₀ multiplied vertical vibration differentiating amplifier (21b) and said output () to K ₉ times ing.

Here, the combination of these amplifiers is the same as that in the case of the horizontal vibration control, and thus the description is omitted.

The output from these amplifiers is the test vibration input device (C)
Along with the electric signal of the test vibration (T) from the controller, it is input to the vertical drive circuit (18) and is input to the control valve (14) to adjust the valve opening, and the air springs (3a) (3b) [(3) (3 ')], the pressure of the air tank (4) is adjusted.

Here, the description of the function of each amplifier is the same as that in the case of the horizontal vibration control, and thus the description thereof is omitted. Note that the vertical subtractor is (34
b), the adder is (35b), and the amplifiers in the figures also have the same numbers for the same functions, and those in the vertical direction have the additional symbol (b). Directional (a)
Is distinguished.

In addition, a feedforward control method can be adopted in place of the feedback control method. That is, the disturbance vibration (G) and the like are preliminarily patterned and stored in a CPU, an external storage device, or the like, and the accelerations () and () of the disturbance vibration (G) immediately before input to the test stand (2) are detected. The control force of the pattern corresponding to this is selected or produced or calculated and feed-forwarded to the actuator (A), or the control force of the pattern corresponding to the operation signal is detected by detecting the operation start signal of the EUT. Selection, production or calculation may be performed, and this may be feed-forwarded to the actuator (A).

It is of course possible to combine the feedback control method and the feedforward control method.

FIG. 6 shows a third embodiment of the present invention in which the horizontal air springs (3a) (3b) [(3) (3 ')] and the vertical air spring (3c) are arranged as shown in FIG. FIG. 3 is a cross-sectional view when the air spring is installed in the opposite direction, and a horizontal air spring (3a) (3b)
The partition plate (26) of [(3) (3 ')] is disposed so as to straddle the vertical air spring (3c).

FIG. 7 shows a fourth embodiment of a horizontal air spring (3a) (3a).
b) [(3) (3 ')], the vertical air spring (3c) and the common base (34).

Next, a case where a piezo element (40) is used as the actuator (A) will be described as a fifth embodiment. The piezo element (40) is an incompressible block having the property of expanding and contracting in proportion to the input voltage. The installation of the piezo element (40) is the same as that of the air spring actuator (A). However, since the piezoelectric element (40) is an incompressible block as described above, the vertical support (7) becomes unnecessary. In addition, the combination of the amplifiers described above needs to add an integration function to perform control equivalent to that of the air spring type actuator (A) due to the characteristics of the piezo element (40).
Even in this case, the vertical integration amplifier is mainly used, and other vertical proportional amplifiers and vertical double integration amplifiers are appropriately combined. Piezo element (40) is a test stand (2)
May be arranged so as to oppose each other, and a control voltage in the opposite direction may be input to each. However, since the stiffness of the piezo element (40) itself is extremely high, only one element is arranged in one direction. You may.

The linear motor (41) is the same as the piezo element (40), and the amplifier configuration is the same as the piezo element (40).

As shown in FIG. 8 (b), the piezo element (40) and the wire (8) << or the laminated material >> are combined to form a test machine stand (2).
May be supported by a supporting elastic body (45), and in this case, one test machine stand (2) can control three axes and six degrees of freedom.

The test vibration is subtracted from the acceleration detected as described above, processed by the amplifier group, and then added to the test vibration, whereby the disturbance vibration (G) and the like are almost canceled out, and the disturbance vibration (G) and the like are cancelled. The actuator (A) can be controlled with the influence reduced as much as possible, and the vibration test can be performed in three dimensions and six degrees of freedom with little disturbance (G) or the like. FIG. 10 to FIG. 11 show control examples in a case where a region having a flat phase is set as a vibration control region.

FIG. 12 is a block circuit diagram for implementing the method of the present invention using only digital control (solid line in the figure) or using analog control (solid line and broken line).

In terms of digital control, the acceleration sensor (1
0) The vibration acceleration in the X, Y, and Z axes taken out from (11) is amplified by a preamplifier, digitized by an A / D converter, input to the CPU, and internally processed to form a vibration suppression waveform.
A digital test waveform fetched from an external device (or processed in the CPU) is superimposed on this and output, and this is converted by a D / A converter and input to the drive amplifier of the actuator (A). It controls the actuator (A).

Also, as shown by the broken line, the vibration suppression control is performed by the analog circuit described, only the test vibration is input by the CPU, added to the D / A converted test vibration, and input to the actuator drive amplifier. ing.

Note that an analog test waveform can also be input. When the analog test waveform is input to an analog control amplifier, the analog control described above is applied.

Also, the analog test waveform can be input to the A / D converter and processed by the CPU. (Effect) The microvibration test apparatus according to the present invention includes a vertical actuator that expands and contracts in the vertical direction to substantially cancel the vertical disturbance vibration of the test machine table and vibrates the test vibration in the vertical direction. A horizontal actuator that is connected, expands and contracts in the horizontal direction, almost cancels the horizontal disturbance vibration of the test stand, and vibrates the test vibration in the horizontal direction, and an operation signal of the disturbance source of the test stand or the test stand. A vertical vibration damping circuit that detects a vertical disturbance vibration input to the vertical actuator and feeds back and / or feeds back a control signal for generating a control force based on the vibration or the operation signal to the vertical actuator; A control for generating a control force based on the vibration or operation signal by detecting an operation signal of a disturbance source of the machine stand or a horizontal disturbance vibration input to the test machine stand. A control signal is fed back to the horizontal actuator and / or a horizontal vibration damping circuit, and a test vibration input device for inputting a test vibration to each of the vertical actuator and the horizontal actuator. The influence is almost eliminated three-dimensionally, and almost pure vibration test by test vibration becomes possible.
In addition to significantly improving the test accuracy, it is also possible to perform a microvibration test at a level equal to or lower than the disturbance that was impossible with the conventional method. Moreover, the microvibration test could be performed three-dimensionally.

[Brief description of the drawings]

Fig. 1 ... Layout plan of microvibration test apparatus according to the present invention Fig. 2 ... Plane sectional view of the present invention Fig. 3 ... Longitudinal sectional view of the present invention Fig. 4 (a) ... FIG. 4B is a block circuit diagram of another embodiment of the present invention. FIG. 5 is a block circuit diagram of a second embodiment of the present invention. 7 is a sectional view of a third embodiment of the invention. FIG. 7 is a sectional view of a fourth embodiment of the present invention. FIG. 8 (a) is a schematic front view when a piezo element is used as an actuator of the present invention. (B): Another schematic front view when a piezo element is used as the actuator of the present invention FIG. 9: Front view when a linear motor is used as the actuator of the present invention FIG. 10: Excitation of the present invention Graph showing control region FIG. 11: Graph showing acceleration control region of the present invention FIG. 12: Method of the present invention Block circuit diagram when used with digital control or analog control (A) Actuator (A ₁ ) Horizontal actuator (A ₂ ) Vertical actuator (B) Vibration suppression feedback circuit (B ₁ ) Horizontal feedback circuit (B ₂ ) Vertical feedback circuit (C) Test vibration input device (G) Disturbance vibration, (S) Vibration suppression vibration or control force (T) Test vibration (2) Test machine stand (3a) Horizontal reference side air spring (3b) Horizontal control side air spring (3c) Vertical air spring (3) (3 ') ... a pair of air springs, (4) ... air tank (5) ... rubber spring part, (7) ... vertical support (8) ... wire or laminated material (10) ... vertical acceleration sensor ( 11) Horizontal acceleration sensor, (14) Control valve (16) Pneumatic source (17) Horizontal drive circuit (18) Vertical drive circuit (19) Regulator (20a) Horizontal vibration integration amplifier (21a) … Horizontal vibration differential amplifier (22a)… Horizontal vibration proportional amplifier (20b)… Vertical integral amplifier (21b)… Vertical differential amplifier (22b)… Vertical proportional amplifier (24)… Fixed seat , (25)… Standing plate (26)… Partition plate, (27)… Circular washer (28)… Base, (29)… Arm (30)… Casing, (31)… Rubber Plate (32) Metal plate (33) Phase inverter (34a) Horizontal subtractor (34b) Vertical subtractor (35a) Horizontal adder (35b) Vertical adder (40) Piezo element, (41) Linear motor (45) Elastic support

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01M 7/00

Claims (1)

(57) [Claims] 1. A vertical actuator which expands and contracts in a vertical direction to substantially cancel a disturbance vibration in a vertical direction of a test machine table and vibrates a test vibration in a vertical direction, and is connected to the test machine table and expands and contracts in a horizontal direction. A horizontal actuator that almost cancels the horizontal disturbance vibration of the test stand and excites the test vibration in the horizontal direction, and the operating vibration of the disturbance source of the test stand or the vertical disturbance input to the test stand. A vertical vibration suppression circuit for detecting vibration and feeding back and / or feed-forward a control signal for generating a control force based on the disturbance vibration or the operation vibration to the vertical actuator; An operation vibration or a horizontal disturbance vibration input to a test machine stand is detected, and a control signal for generating a control force based on the disturbance vibration or the operation vibration is transmitted to the water. A microvibration test apparatus comprising: a horizontal vibration damping circuit for feeding back and / or feedforward to a directional actuator; and a test vibration input device for inputting test vibration to each of a vertical actuator and a horizontal actuator. .