JP4388009B2 - Vibration isolator - Google Patents

Description

  The present invention relates to a vibration isolator, and more particularly, to a vibration isolator capable of effectively isolating a vibration isolation object that can move in a horizontal direction on a surface plate.

  In precision equipment that requires high-precision specifications, such as semiconductor manufacturing equipment, liquid crystal manufacturing equipment, and high-precision machine tools, in addition to insulating external vibration that can be transmitted to the equipment side, reducing the vibration generated by moving objects such as the stage to be mounted. For this purpose, for example, an active vibration isolator or the like is used to install the precision device. This active vibration isolator actively imparts vibration in the direction opposite to the direction of vibration to be damped.

  This type of device includes a plurality of position sensors that detect the position of the surface plate that is displaced by external vibration and an acceleration sensor that detects the acceleration of the surface plate, and inputs signals output from these sensors to the controller. Furthermore, after the feedback control, a vibration isolator of a type that outputs a control signal to a servo valve to drive and control an air spring actuator has been put into practical use.

  However, in such a vibration isolator, the displacement and acceleration of the surface plate can be detected after the inclination of the surface plate actually occurs, and in particular, the object to be isolated mounted on the surface plate is For example, in the case of a moving body that moves in the horizontal direction, the tilt remains on the surface plate even if active control is performed, and thus the above-described feedback control is limited.

Therefore, there is known a vibration isolator that applies so-called SFF control (stage feed forward control) to reduce vibration of the surface plate (see, for example, Patent Document 1).
Japanese Patent No. 3224489

  However, in the above-described air spring type actuator, there is a time delay from the supply / exhaust control signal to the actual completion of supply / exhaust of the air spring. If the pressure feedback control (minor control loop) is provided and the responsiveness of the servo valve is not improved, the SFF control does not function effectively.

  Here, when pressure feedback is performed, it is necessary to dispose a pressure sensor in the actuator and to provide a pressure feedback circuit in the controller, resulting in an increase in cost due to an increase in the number of parts and a decrease in design flexibility. It will be.

  Therefore, the present invention has been made to solve such problems, and it is possible to improve the response of the operation control of the surface plate with respect to external vibration and obtain a good vibration isolation performance with a relatively simple configuration. The purpose is to provide a vibration device.

To achieve the above object, anti-vibration apparatus according to the present invention includes a platen divided Futai elephants moving object that can be moved in the horizontal direction is mounted, the constant of the dividing Futai elephants moving object is mounted A plurality of acceleration sensors for detecting vibration of the board, a plurality of position sensors for detecting the position of the surface plate, feedback control of outputs of the acceleration sensor and the position sensor, and a deviation between vibration and position are controlled. A plurality of air spring actuators that respectively support a plurality of locations of the surface plate, a servo valve that supplies and exhausts air springs provided in the air spring actuator, and the vibration isolation pair on the surface plate A position signal output unit for detecting a horizontal position of the moving object and outputting a position signal corresponding to the detected position; and a signal indicating a proportional value of the position signal output from the position signal output unit. Output A control unit having an example device, and a pseudo-differentiator that outputs a signal obtained by multiplying a pseudo-differential value of the position signal output from the position signal output unit by a predetermined gain value, and The control unit includes a feedback control signal generated based on outputs of the acceleration sensor and the position sensor, and a feedforward control signal obtained by adding signals output from the proportionalator and the pseudo-differentiator, respectively. the by outputting to the servo valve side by adding, individually controls intake and exhaust operations of the plurality of air spring actuator to eliminate the inclination of the surface plate, characterized by a crotch.

Moreover, anti-vibration apparatus of the present invention, the detected horizontal accelerations of the dividing Futai elephant movement thereof in the surface plate, the acceleration signal output unit for outputting an acceleration signal corresponding to the detected acceleration The control unit further includes a value obtained by multiplying a signal obtained by adding the feedforward control signal and the feedback control signal by a predetermined gain to a pseudo differential value of the acceleration signal output from the acceleration signal output unit. the further addition was based on a signal obtained by, characterized in that that control individual supply and exhaust operation of said plurality of air spring actuators.

Furthermore, in the vibration isolator according to the present invention, the control unit supplies and exhausts the plurality of air spring actuators based on at least the feedforward control signal and the feedback control signal that have passed through a low-pass filter and / or a notch filter. characterized in that that control individual operation.

  As described above, according to the present invention, it is possible to provide a vibration isolator capable of improving the response of the operation control of the surface plate to the external vibration with a relatively simple configuration and obtaining good vibration isolation performance. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a perspective view showing a vibration isolation device according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a vibration damping mechanism in which a plurality of actuators and sensors provided in the vibration isolation device are unitized. FIG. 3 is a diagram functionally showing the configuration of the main part of the vibration isolator. In addition, in FIG. 1, in order to make it easy to visually grasp the structure of the vibration isolator, the surface plate provided in the vibration isolator and two stages as vibration isolating objects mounted on the surface plate are provided. Shown with a chain line.

  As shown in FIGS. 1 to 3, the vibration isolator 1 of this embodiment is an active vibration isolator, and includes a support base 3 fixed to a floor surface and a stage 45 as a vibration isolation object. Mounted surface plate (base) 2, air spring type actuators 41 to 44 and 11 to 14 having air springs formed of a hollow rubber body, position sensors 21 to 23, position sensors 25 to 28, and A position sensor 46, an acceleration sensor 49, servo valves 38 and 48 for individually supplying and exhausting air springs of the actuators 41 to 44 and 11 to 14, and a storage unit 36a for comprehensively controlling these hardware are provided. And a control device (controller) 36. Here, the stage 45 as the vibration isolation object is configured as a moving body that moves in the horizontal direction (x direction and y direction), for example.

  The actuators 41 and 11 and the sensor 25, the actuators 42 and 12 and the sensors 21 and 26, the actuators 43 and 13 and the sensors 22 and 27, and the actuators 44 and 14 and the sensors 23 and 28 are divided into four units. The vibration control mechanism shown in FIG. 2 is configured. The bottoms of these united damping mechanisms are fixed via the bottom plate 16 at the four corners on the support base 3 whose upper surface is often formed in a rectangular (quadrangle) shape. The platen 2 is fixed to the four corners of the platen 2 so as to support the platen 2 from below through the upper plate 15. The vibration isolation device 1 does not necessarily include the support base 3 described above. For example, the support base 3 is deleted from the components of the vibration isolation device 1 and the bottom plate 16 of the vibration suppression mechanism is directly fixed to the floor surface. You may do it.

  As shown in FIGS. 1 to 3, the actuators 41 to 44 support the surface plate 2 so as to be movable in the horizontal direction (the direction along the mounting surface of the vibration isolation object on the surface plate 2). The actuators 41 to 44 are arranged in two sets at positions that are point-symmetric with respect to the center of gravity of the surface plate 2 as viewed from the vertical direction (positions that sandwich the center of gravity of the surface plate 2 from the horizontal direction). On the other hand, the actuators 11 to 14 support the surface plate 2 so as to be movable in the vertical direction (direction perpendicular to the mounting surface of the vibration isolation object on the surface plate 2: Z direction). The position sensors 21 to 23 detect the horizontal position (displacement) of the surface plate 2. Further, the position sensors 25 to 28 detect the position (displacement) of the surface plate 2 in the vertical direction. The acceleration sensor 49 detects acceleration generated on the surface plate 2. The position sensor 46 detects the position of the stage 45 that moves in the horizontal direction on the surface plate 2, that is, the relative position (relative horizontal position) of the stage 45 with respect to a predetermined position of the surface plate 2.

  The four actuators 41 to 44 are respectively provided with the servo valves 38 described above, and the control device 36 is based on the detection results of the position sensors 21, 22, 23, the acceleration sensor 49, and the position sensor 46. Thus, the actuators 41 to 44 are individually driven and controlled via the four servo valves 38 so that the surface plate 2 is positioned at a predetermined position (horizontal position) in the horizontal direction. Specifically, the control device 36 individually controls the opening / closing amount of the servo valve 38 based on the detection results of the sensors, that is, individually supplies and exhausts the air springs provided in the actuators 41 to 44.

  The four actuators 11 to 14 are each provided with the servo valve 48 described above, and the control device 36 is based on the detection results of the position sensors 25 to 28, the acceleration sensor 49, and the position sensor 46. The actuators 41 to 44 are individually driven and controlled via the four servo valves 48 so that the surface plate 2 is positioned at a predetermined position (height position) in the horizontal direction. Specifically, the control device 36 individually controls the opening / closing amount of the servo valve 48 based on the detection result of each sensor, that is, individually supplies and exhausts the air springs provided in the actuators 11 to 14. Here, as the acceleration sensor 49, at least two or more plural acceleration sensors 49 can be detected so that acceleration generated in the horizontal direction with respect to the surface plate 2 and acceleration generated in the vertical direction with respect to the surface plate 2 can be individually detected. It may be provided.

  Next, the structure of the control apparatus 36 with which the vibration isolator 1 of this embodiment is provided is demonstrated based on FIG.4 and FIG.5. Here, FIG. 4 is a block diagram functionally showing the configuration of each part realized by the control device 36 by software, and FIG. 5 is a diagram of the surface plate corresponding to the horizontal movement of the stage 45 performed by the control device 36. It is a schematic diagram which shows a proportional control notionally. Here, in order to make the invention easier to understand, the operation control in the vertical direction of the surface plate 2 (inclination direction of the surface plate) is taken as an example and described.

  That is, the control device 36 refers to the content stored in the storage unit 36a, and controls a feedback (hereinafter referred to as “FB”) control unit 50a and a stage feed forward (hereinafter referred to as “SFF”) control unit. 60a and an adder 72 that adds signals respectively output from the FB control unit 50a and the SFF control unit 60a are realized by software.

  The FB control unit (FB control loop) 50 a includes a target setting unit 51, a proportional product (proportion / integral / differential) unit 52, a proportional product product 53, and an adder 72. The outputs of the position sensors 25 to 28 and the acceleration sensor 49 described above are input to the control device (controller) 36 via a preamplifier, are A / D converted, and are further calculated by digital calculation. The target setting unit 51 sets the target heights of the four corners of the surface plate 2 to be controlled by the actuators 11 to 14 based on the detection results of the height positions of the four corners of the surface plate 2 detected by the position sensors 25 to 28. To do. The proportional product 52 obtains a deviation between the set value (target value) of the target height and the detected value (current value) detected by the position sensors 25 to 28, and outputs a control signal for making the deviation zero. Output. The proportional product 53 outputs an input value from the acceleration sensor 49 and a value obtained by inverting the input value as a control signal so as to cancel the acceleration generated on the surface plate 2. The adder 72 outputs a signal obtained by adding the signal input from the proportional differential product unit 52 side and the signal input from the proportional differential product unit 53 to the adder 72 side as a feedback control signal.

  The SFF control unit 60 a includes a distributor 61, a proportional device 62, a pseudo differentiator 63, and an adder 64. The output of the position sensor 46 described above is input into the control device 36 via a preamplifier, is A / D converted, and is further calculated by digital calculation. The distributor 61 outputs the position signal L1 output from the position sensor 46 and further A / D converted to the proportional device 62 and the pseudo differentiator 63, respectively. The proportional device 62 outputs the proportional value of the position signal input from the distributor 61 side to the adder 64 side. The pseudo differentiator 63 performs pseudo differentiation (differential compensation) on the position signal input from the distributor 61 side, and outputs a signal obtained by multiplying this signal by a predetermined gain value to the adder 64 side. The adder 64 adds the signals respectively output from the proportional device 62 and the pseudo-differentiator 63, and outputs this to the adder 72 side as a feedforward control signal.

  That is, as shown in FIG. 5, the SFF control unit 60a performs the horizontal direction so as to cancel the moment mgL generated when the stage (weight mg) 45 of mass m moves on the surface plate 2 by the distance L in the horizontal direction. Are provided to individually control the actuators 11 to 14 arranged with a pitch P therebetween. Specifically, the SFF control unit 60a is an air spring type having an integrator element that causes a time delay from the start of the actual supply / exhaust control to the completion of the desired supply / exhaust of the air spring. In order to compensate for the specification defects of the actuators 11 to 14, the displacement of the stage 45 on the surface plate 2 can be detected and reflected in the control of the inclination of the surface plate 2.

The signals output from the SFF control unit 60 a and the above-described FB control unit 50 a are added by the adder 72, D / A converted, and output to the servo valve 48. According to the control signal (voltage) input to the servo valve 48, the air springs of the actuators 11 to 14 are individually supplied and exhausted, whereby the position control and the surface plate for holding the target position of the surface plate 2 are performed. Acceleration control that cancels the vibration of 2 is realized.
In the above description, A / D and D / A conversion are used for signal transmission to the controller and are described via analog signals. However, a serial or parallel digital signal may be used for the controller.

  As described above, according to the vibration isolation device 1 according to the present embodiment, it is possible to improve the responsiveness of the operation control of the surface plate 2 with respect to external vibration and obtain a good vibration isolation performance with a relatively simple configuration. .

(Second Embodiment)
Next, a second embodiment of the present invention will be described based on FIGS. 6 and 7, FIGS. 8a to 8c, and FIGS. 9a and 9b. Here, FIG. 6 is a block diagram functionally showing the configuration of each unit realized by software by the control device 86 provided in the vibration isolation device of this embodiment, and FIG. 7 is a stage performed by the control device 86. FIG. 5 is a schematic diagram conceptually showing the control of the surface plate corresponding to the acceleration generated in 45. 8A is a diagram showing an output waveform of the position sensor 46, FIG. 8B is a waveform diagram corresponding to the moving speed of the stage 45 shown as a reference diagram, and FIG. 8C is a diagram showing an output waveform of the acceleration sensor 47. . Further, FIG. 9a is a diagram showing the responsiveness corresponding to the displacement in the tilt direction of the surface plate 2 by the control device 86 of this embodiment, and FIG. 9b is the view of the tilt direction of the surface plate 2 by the control device 86 of this embodiment. It is a figure which shows the responsiveness corresponding to an acceleration. In these drawings, the same components as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

That is, the vibration isolation device of this embodiment includes a control device 86 instead of the control device 36 provided in the vibration isolation device 1 of the first embodiment, and further includes an acceleration sensor 47. The acceleration may be directly measured by the acceleration sensor, the differential value (pseudo differential value) of the speed sensor may be used, or the second order differential (pseudo differential value) of the position sensor may be used.
The control device 86 includes an SFF control unit 60 b instead of the SFF control unit 60 a of the control device 36, and further includes an adder 73.

  The SFF control unit 60b further includes a pseudo differentiator 65 in addition to the configuration of the SFF control unit 60a. The acceleration sensor 47 detects the acceleration of the stage 45 that moves in the horizontal direction on the surface plate 2. Separately from the output of the position sensor 46 illustrated in FIG. 8 a, the output of the acceleration sensor 47 illustrated in FIG. 8 c is input into the control device 36 via the preamplifier and then A / D converted. The signal α1 is input to the pseudo-differentiator 65. The pseudo differentiator 65 performs pseudo differentiation (differential compensation) on the acceleration signal α1 and outputs a signal obtained by multiplying this signal by a predetermined gain value to the adder 73 side.

  That is, as shown in FIG. 7, when the stage 45 having a mass m moves on the surface plate 2 with an acceleration α in the horizontal direction, the SFF control unit 60 b generates a moment in the direction in which the surface plate 2 tilts due to the reaction force. It is provided for individually controlling the actuators 11 to 14 so as to cancel out mαh (where h is the distance between the center of gravity of the stage 45 and the center of gravity of the surface plate 2 in the vertical direction). Yes.

  That is, in the control device 86 according to the vibration isolation device of this embodiment, the signals output from the adders 64 of the FB control unit 50a and the SFF control unit 60b are added by the adder 72, and the added signal and The signal output from the pseudo-differentiator 65 of the SFF controller 60 b is further added by the adder 73, and then D / A converted and output to the servo valve 48. According to the control signal (voltage) input to the servo valve 48, the air springs of the actuators 11 to 14 are individually supplied and exhausted, whereby the position control and the surface plate for holding the target position of the surface plate 2 are performed. Acceleration control that cancels the vibration of 2 is realized.

  Here, FIG. 9a and FIG. 9b described above are the platen rotational displacement (fixed) between the case where only the FB control unit (FB control loop) 50a is used and the case where the SFF control unit 60b is added to the FB control unit 50a. It is the data which measured the responsiveness of the displacement of the inclination direction of the board | plate 2, and the responsiveness of the surface plate rotational acceleration (acceleration of the inclination direction of the surface board 2). That is, in the case of only the FB control, since the FB control starts after the rotational displacement of the surface plate (the inclination of the surface plate) occurs, a large inclination occurs in the surface plate 2, but by using the SFF control together. It can be seen that the rotational displacement is reduced to about 1/10. Moreover, in FIG. 9b, it turns out that the acceleration of the inclination direction of the surface plate 2 is reduced to about 1/2 by using SFF control together.

  Therefore, according to the vibration isolator according to the present embodiment, the responsiveness of the operation control of the surface plate 2 is further improved with respect to the vibration isolator of the first embodiment, and the vibration isolation performance can be further improved. it can.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. Here, FIG. 10 is a block diagram functionally showing the configuration of each unit realized by software by the control device 96 provided in the vibration isolation device of this embodiment. In FIG. 10, the same components as those described in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  That is, the vibration isolation device of this embodiment includes a control device 96 having an FB control unit 50c and an SFF control unit 60c instead of the control device 86 provided in the vibration isolation device of the second embodiment. Has been. Specifically, the control device 96 includes a proportional differential product section 52 and an adder 71, a proportional differential product section 53 and an adder 71, an adder 64 and an adder 72, and a pseudo-differentiation. Filter units 54, 55, 66, 67 realized by a low-pass filter, a notch filter or the like having an appropriate amplification degree and time constant are provided between the unit 65 and the adder 73, respectively.

  Thereby, according to the vibration isolator which concerns on this embodiment, in addition to the effect acquired by the vibration isolator of 1st, 2nd embodiment, the signal aiming at the removal of the noise and the structural resonance phenomenon of an apparatus main body The processing is realized, and thereby the vibration isolation performance can be further improved.

The present invention has been specifically described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the invention. That is, in each of the above-described embodiments, the operation control in the vertical direction of the surface plate 2 (the inclination direction of the surface plate) is taken as an example to facilitate the understanding of the invention. It is also possible to realize the SFF control in the horizontal direction of the surface plate 2 by applying the control illustrated in FIG. 4, FIG. 6, and FIG.
In addition, many parts of this content are realized by software. For system flexibility, it is desirable to implement with software, but a part of it may be replaced with hardware.

The perspective view which shows the vibration isolator which concerns on the 1st Embodiment of this invention. FIG. 2 is a cross-sectional view showing a vibration damping mechanism in which a plurality of actuators and sensors provided in the vibration isolator of FIG. 1 are unitized. The figure which shows the structure of the principal part of the vibration isolator of FIG. 1 functionally. The block diagram which shows the structure of each part which the control apparatus with which the vibration isolator of FIG. 1 is provided implement | achieves by software. The schematic diagram which shows notionally the proportional control of the surface plate corresponding to the horizontal movement of a stage which the control apparatus with which the vibration isolator of FIG. 1 is provided performs. The block diagram which shows functionally the structure of each part which the control apparatus provided in the vibration isolator which concerns on the 2nd Embodiment of this invention implement | achieves by software. The schematic diagram which shows notionally the control of the surface plate corresponding to the acceleration which arises in a stage performed by the control apparatus of FIG. The figure which shows the output waveform of the position sensor which detects the position of the stage of FIG. The waveform diagram corresponding to the moving speed of the stage of FIG. The figure which shows the output waveform of the acceleration sensor which detects the acceleration of the stage of FIG. The figure which shows the responsiveness corresponding to the displacement of the inclination direction of the surface plate by the control apparatus of 2nd Embodiment. The figure which shows the responsiveness corresponding to the acceleration of the inclination direction of a surface plate by the control apparatus of 2nd Embodiment. The block diagram which shows functionally the structure of each part which the control apparatus provided in the vibration isolator of the 3rd Embodiment of this invention implement | achieves with software.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vibration isolator, 2 ... Surface plate, 11-14, 41-44 ... Actuator, 21-23, 25-28, 46 ... Position sensor, 36, 86, 96 ... Control apparatus, 36a ... Memory | storage part, 38, 48 ... servo valve, 45 ... stage, 47,49 ... acceleration sensor, 50a, 50c ... feedback (FB) control unit, 51 ... target setting unit, 52,53 ... proportional product unit, 54,55,66, 67: Filter section, 60a, 60b, 60c: Stage feed forward (SFF) control section, 62: Proportionator, 63, 65: Pseudo differentiator, 64, 71, 72, 73: Adder.

Claims (3)

A surface plate dividing Futai elephants moving object capable of moving in the horizontal direction is mounted,
A plurality of acceleration sensors for detecting vibration of the surface plate in which the dividing Futai elephants moving object is mounted,
A plurality of position sensors for detecting the position of the surface plate;
A plurality of air spring actuators that respectively support a plurality of portions of the surface plate, which are provided for feedback control of outputs of the acceleration sensor and the position sensor, and to control a deviation between vibration and position;
A servo valve for supplying and exhausting an air spring provided in the air spring actuator;
Wherein detecting a horizontal position of the dividing Futai elephant movement thereof in the surface plate, and the position signal output unit that outputs a position signal corresponding to the detected position,
Obtained by multiplying a proportional unit that outputs a signal indicating a proportional value of the position signal output from the position signal output unit and a pseudo-differential value of the position signal output from the position signal output unit by a predetermined gain value. A control unit having a pseudo-differentiator for outputting the received signal;
With
Further, the control unit is a feedforward control signal obtained by adding a feedback control signal generated based on outputs of the acceleration sensor and the position sensor, and a signal output from each of the proportionalator and the pseudo-differentiator. And adding and outputting to the servo valve side individually controls the intake and exhaust operations of the plurality of air spring actuators so as to eliminate the inclination of the surface plate.
Anti-vibration apparatus is characterized and this. Wherein detecting a horizontal acceleration of the vibration Futai elephant movement thereof in the surface plate, further comprising an acceleration signal output unit for outputting an acceleration signal corresponding to the detected acceleration,
The control unit further adds a value obtained by multiplying a pseudo differential value of the acceleration signal output from the acceleration signal output unit by a predetermined gain to a signal obtained by adding the feedforward control signal and the feedback control signal. based on a signal obtained by, vibration isolator according to claim 1, wherein the that control individual supply and exhaust operation of said plurality of air spring actuators. Wherein the control unit, characterized in that on the basis of at least the feedforward control signal and the feedback control signal has passed through the low-pass filter and / or notch filter, Gosuru individually control the supply and exhaust operation of said plurality of air spring actuator The vibration isolator according to claim 1 or 2.

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