JP2006022858A - Vibration resistant apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration resistant apparatus that has a simple configuration, is inexpensive, and can perform vibration resistant control efficiently. <P>SOLUTION: The vibration resistant apparatus 1 comprises a vibration resistant table 3 for placing an object 2; an air spring 10 for floating and supporting the vibration resistant table 3 in the vertical direction for positioning; an electromagnetic actuator 20 for controlling the vibration in the vertical and horizontal directions of the vibration resistant table 3 and for positioning; acceleration sensors AZ1-AZ3 for detecting the vibration of the vibration resistant table; and displacement sensors Z1-Z4 for detecting the position of the vibration resistant table 3. In the vibration resistant apparatus 1, a first control circuit 40 for controlling the air spring 10 and a second control circuit 50 for controlling the electromagnetic actuator 20 are provided separately, the position of the vibration resistant table is controlled by the control circuit 40, and the vibration of the vibration resistant table 3 is controlled by the control circuit 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-accuracy vibration isolation device that blocks vibration transmitted from an installation floor to a semiconductor manufacturing apparatus, an electron microscope, or the like, or suppresses vibration of the apparatus itself that adversely affects product yield, measurement observation accuracy, and the like. In particular, the present invention relates to an air spring / electromagnetic actuator combined type vibration isolation device in which a vertical support force is mainly allocated by an air spring and precise vibration isolation control is mainly allocated by an electromagnetic actuator.

  Conventionally, a mechanical device such as a semiconductor manufacturing apparatus and an electron microscope that is not susceptible to vibration has been installed in a vibration isolator and installed in a factory or the like. An anti-vibration device (active anti-vibration device) using magnetic levitation using an electromagnetic actuator that can realize high-performance vibration isolation has been developed in place of the traditional passive vibration isolator using air springs and rubber. Yes. By the way, when performing the active control, if the weight of the vibration isolation table and the mounted object is heavy, the necessary control force is too large to support the suspension with only the force generated by the electromagnetic actuator. Therefore, there is a vibration isolator configured to support the weight of the load using an electromagnetic actuator and an air spring in combination.

  In other words, the majority of the weight of the vibration isolation table on which the mechanical device is mounted is supported by the air spring, and the vibration is removed by controlling the electromagnetic actuator. In this vibration isolation device, the vibration isolation table and the mounted object are levitated and supported in a stable state by an air spring, and then controlled by an electromagnetic actuator to perform vibration isolation in a more precise and stable state.

  By the way, in this vibration isolator, the vibration damping table is suppressed while positioning the vibration isolating table in the vertical direction with an air spring. Further, the electromagnetic actuator mainly suppresses vibration of the vibration isolation table and positions the vertical and horizontal directions. That is, the position control and vibration control of the vibration isolation table are performed by both the air spring and the electromagnetic actuator. Therefore, both the displacement sensor signal output from the displacement sensor that detects the position of the vibration isolation table and the acceleration signal output from the acceleration sensor that detects the vibration of the vibration isolation table are sent to the same control circuit. It was configured to control the operation of both the air spring and the electromagnetic actuator.

  However, the air spring has the ability to generate a large force, but has the property that it cannot follow a high frequency, while the electromagnetic actuator has the property that it can generate a high frequency force but cannot generate a very large force. Have. Thus, the air spring and the electromagnetic actuator have completely different properties. For this reason, if both the air spring and the electromagnetic actuator are controlled by the same control circuit as described above, there is a problem that they cannot be efficiently controlled with high accuracy to be isolated.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a vibration isolation device capable of efficiently performing vibration isolation control utilizing the characteristics of the air spring and the electromagnetic actuator. .

  The invention described in claim 1 of the present application includes a vibration isolation table on which an object is placed, an air spring that supports and positions the vibration isolation table, and an electromagnetic actuator that controls vibration of the vibration isolation table. The vibration device is characterized in that a first control circuit for controlling the air spring and a second control circuit for controlling the electromagnetic actuator are separately provided.

  The invention according to claim 2 of the present application is the vibration isolation device according to claim 1, further comprising an acceleration sensor for detecting vibration of the vibration isolation table and a displacement sensor for detecting the position of the vibration isolation table. The control circuit has a function of causing the air spring to control the position of the vibration isolation table using the displacement signal from the displacement sensor as an input signal, and the second control circuit uses the acceleration signal from the acceleration sensor as an input signal to the electromagnetic actuator. It has a function of performing vibration control of the vibration isolation table.

  According to a third aspect of the present invention, in the vibration isolation device according to the first or second aspect, both the first control circuit and the second control circuit include a digital control circuit.

  According to the first aspect of the present invention, the first control circuit for controlling the air spring and the second control circuit for controlling the electromagnetic actuator are provided separately. It is possible to control efficiently while taking advantage of the features. Further, the configuration of the first control circuit and the second control circuit is simplified and the size thereof can be reduced, and the configuration of the vibration isolation device is simple and inexpensive.

  According to the second aspect of the present invention, the first control circuit inputs the displacement signal from the displacement sensor and causes the air spring to control the position of the vibration isolation table, and the second control circuit includes the acceleration signal. Since the acceleration signal from the sensor is input and the vibration control of the vibration isolation table is performed by the electromagnetic actuator, the air spring and the electromagnetic actuator can be efficiently and accurately controlled while taking advantage of the respective characteristics.

  According to the third aspect of the present invention, since the first control circuit and the second control circuit are both equipped with digital control circuits, the air spring and the electromagnetic actuator are used with high accuracy and appropriateness while taking advantage of the respective characteristics. Can be controlled.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of a vibration isolation device 1 according to an embodiment of the present invention, where FIG. 1A is a plan view of the vibration isolation device 1 and FIG. 1B is a side view thereof. . The vibration isolation device 1 includes a vibration isolation table 3 on which a placement object (object) 2, which is a precision machine such as an electron microscope or a semiconductor manufacturing apparatus, is mounted on a base 4 by an actuator unit 30 including an air spring 10 and an electromagnetic actuator 20. The configuration supported above. The gantry 4 is installed on the installation surface 7 via the mounting table 5 and the support legs 6. In the present embodiment, the case where the vibration isolation table 3 is divided into four pieces is shown, but the vibration isolation table 3 may be composed of a single piece. The actuator unit 30 is disposed below each vibration isolation table 3. An air spring control circuit (first control circuit) 40 is connected to the air spring 10, and an electromagnetic actuator control circuit (second control circuit) 50 is connected to the electromagnetic actuator 20.

  The vibration isolation table 3 is provided with acceleration sensors AZ1 to AZ3 that detect the vibration. The acceleration sensors AZ1 to AZ3 may be installed at any position as long as the vibration of the vibration isolation table 3 can be detected. Preferably, it is installed at the corner of the vibration isolation table 3 having the largest amount of movement in the vertical direction. In FIG. 1, three of the vibration isolation tables 3 are installed at the corners of the vibration isolation tables 3.

  Although not shown in FIG. 1, the vibration isolation table 3 is provided with displacement sensors Z1 to Z4 (see FIG. 3) for detecting the position. The displacement sensors Z <b> 1 to Z <b> 4 are disposed, for example, in the vicinity of the actuator unit 30 on the lower surface of each vibration isolation table 3 in order to increase the accuracy of position measurement of the vibration isolation table 3. Alternatively, it can be incorporated into the electromagnetic actuator 20 as described below.

  The configuration of the actuator unit 30 will be described. The air spring 10 floats and supports the vibration isolation table 3 in the vertical direction by air pressure. On the other hand, FIG. 2 is a schematic sectional side view showing the configuration of the electromagnetic actuator 20. As shown in the figure, the electromagnetic actuator 20 includes a movable portion 21 and a fixed portion 22, and the fixed portion 22 oscillates in the horizontal direction of the movable portion 21 at a position surrounding the outer periphery of the shaft portion 21 a of the movable portion 21. A radial magnetic coil 23 for controlling the above is installed. An axial magnetic coil 25 for controlling the vertical vibration of the movable portion 21 is installed at a position sandwiching the upper and lower sides of the axial disk 24 provided at the lower end of the shaft portion 21a.

  Further, a radial displacement sensor 26 for detecting the horizontal displacement of the movable portion 21 is disposed at a position facing the outer periphery of the shaft portion 21a, and at a position facing the sensor target 27 installed on the lower surface of the axial disk 24, An axial displacement sensor 28 that detects the vertical displacement of the movable portion 21 is disposed. The radial displacement sensor 26 and the axial displacement sensor 28 constitute a displacement sensor Z1 (or any one of Z2 to Z4). The movable portion 21 is fixed to the vibration isolation table 3, and the fixed portion 22 is fixed to the gantry 4. The radial magnetic coil 23 and the axial magnetic coil 25 of the electromagnetic actuator 20 are controlled by the electromagnetic actuator control circuit 50 so as to remove the vibration of the vibration isolation table 3. Further, the vibration isolation table 3 can be positioned by the radial magnetic coil 23 and the axial magnetic coil 25.

  In FIG. 1, the actuator unit 30 is shown in which the air spring 10 and the electromagnetic actuator 20 that are separately configured are arranged side by side. However, the actuator unit 30 is not limited to this, and the air spring 10 is disposed inside the air spring 10. An electromagnetic actuator 20 may be installed, or an air spring 10 may be provided inside the electromagnetic actuator 20.

  FIG. 3 shows a block configuration of an air spring control circuit 40 that controls the air spring 10, and FIG. 4 shows a block configuration of an electromagnetic actuator control circuit 50 that controls the electromagnetic actuator 20. The air spring control circuit 40 and the electromagnetic actuator control circuit 50 are provided separately. First, the air spring control circuit 40 includes an A / D converter 41, a mode calculator 42, a controller 43, a mode distributor 44, and a D / A converter 45. Each displacement signal of the vibration isolation table 3 detected by the displacement sensors Z1 to Z4 is input to the air spring control circuit 40, A / D converted by the A / D converter 41, and input to the mode calculator 42. Is done. The mode calculator 42 calculates the mode of each displacement signal, and each displacement signal is converted into a predetermined displacement signal Z, α, β for each motion mode. The displacement signals Z, α, and β for each motion mode are input to the controller 43, and calculation processing with a command voltage or the like is performed. Here, the controller 43 is a digital control circuit and can be arbitrarily set by a program. The motion mode-specific displacement signals Z, α, and β calculated by the controller 43 are input to the mode distributor 44 and converted into drive signals Faz1 to Faz4 for driving and controlling the air springs 10. The drive signals Faz1 to Faz4 are input to the D / A converter 45 and output to the air springs 10 via the control valves 15. In this manner, by controlling the air pressure of each air spring 10 based on the output signals of the displacement sensors Z1 to Z4, the vibration isolation table 3 is positioned at a certain target position and controlled to fly.

  On the other hand, similarly to the air spring control circuit 40, the electromagnetic actuator control circuit 50 includes an A / D converter 51, a mode calculator 52, a controller 53, a mode distributor 54, and a D / A converter 55. The electromagnetic actuator control circuit 50 receives each vibration signal of the vibration isolation table 3 detected by the acceleration sensors AZ1 to AZ3, A / D-converted by the A / D converter 51, and input to the mode calculator 52. Is done. The mode calculator 52 calculates the mode of each vibration signal and converts it into predetermined control signals Z, α, β for each motion mode. The vibration signals Z, α, and β for each motion mode are input to the controller 53, and calculation processing with the command voltage and the like is performed. The controller 53 is a digital control circuit and can be arbitrarily set by a program. The motion mode-specific vibration signals Z, α, and β calculated by the controller 53 are input to the mode distributor 54 and converted into control signals Faz1 to Faz4 for driving and controlling the electromagnetic actuators 20. The control signals Faz1 to Faz4 are input to the D / A converter 55 and output to the electromagnetic actuators 20 through the current amplifiers 29. Thus, the vibration of the vibration isolation table 3 is controlled by controlling the driving of the electromagnetic actuator 20 based on the output signals of the acceleration sensors AZ1 to AZ3.

  As described above, the air spring control circuit 40 that controls the air spring 10 and the electromagnetic actuator control circuit 50 that controls the electromagnetic actuator 20 are provided separately, and the position control of the vibration isolation table 3 is performed by the air spring control circuit 40 and the air spring 10. Since the vibration control of the vibration isolation table 3 is performed by the electromagnetic actuator control circuit 50 and the electromagnetic actuator 20, the air spring 10 and the electromagnetic actuator 20 are efficiently and accurately controlled while taking advantage of the respective characteristics. be able to. Further, it is possible to reduce the size and cost of the vibration isolation device. Furthermore, since both the air spring control circuit 40 and the electromagnetic actuator control circuit 50 are provided with a digital control circuit, the air spring 10 and the electromagnetic actuator 20 can be accurately and appropriately controlled while taking advantage of the respective features. .

  In the vibration isolator 1, when the air spring 10 is used only for position control of the vibration isolation table 3 as described above, the air spring control circuit 40 includes the DC component of the output signals of the displacement sensors Z1 to Z4. Since only the low frequency part needs to be controlled, the sampling frequency of the A / D converter 41 does not need to be so high. On the other hand, since the electromagnetic actuator 20 requires a response speed in order to perform vibration control by the acceleration signals output from the acceleration sensors AZ1 to AZ3, the sampling frequency of the A / D converter 51 is set in the electromagnetic actuator control circuit 50. Although it is necessary to select a high one, the electromagnetic actuator 20 has a sufficient response speed, so there is no need to provide a special mechanism for that purpose. Further, since the electromagnetic actuator 20 is configured not to control the position of the vibration isolation table 3, the electromagnetic actuator 20 does not need to generate a large force due to a direct current. And the size of the electromagnetic actuator 20 itself can be reduced. Therefore, the vibration isolator 1 can be made compact.

  The configurations of the air spring control circuit 40 and the electromagnetic actuator control circuit 50 are not limited to the above. The air spring control circuit 40 is connected to the air spring 10 by the output signals of the displacement sensors Z1 to Z4. Any configuration can be used as long as it allows position control, and the electromagnetic actuator control circuit 50 can perform any vibration control of the vibration isolation table 3 on the electromagnetic actuator 20 based on the output signals of the acceleration sensors AZ1 to AZ3. Other configurations may be used.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. Note that any shape or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are achieved.

It is a figure which shows the vibration isolator concerning one Embodiment of this invention, The figure (a) is a top view, The figure (b) is a side view. 3 is a schematic sectional side view showing an electromagnetic actuator 20. FIG. 3 is a block diagram showing a configuration of an air spring control circuit 40. FIG. 3 is a block diagram showing a configuration of an electromagnetic actuator control circuit 50. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibration isolator 2 Mounted object 3 Vibration isolation table 4 Mounting base 5 Mounting base 6 Support leg 7 Installation surface 8 Acceleration sensor 10 Air spring 15 Control valve 20 Electromagnetic actuator 21 Movable part 21a Shaft part 22 Fixed part 23 Radial magnetic coil 24 Axial disk 25 Axial magnetic coil 26 Radial displacement sensor 27 Sensor target 28 Axial displacement sensor 29 Current amplifier 30 Actuator unit 40 Air spring control circuit 41 A / D converter 42 Mode calculator 43 Controller 44 Mode distributor 45 D / A converter 50 Electromagnetic Actuator control circuit 51 A / D converter 52 Mode calculator 53 Controller 54 Mode distributor 55 D / A converters Z1 to Z4 Displacement sensors AZ1 to AZ4 Acceleration sensor

Claims (3)

  An anti-vibration device comprising: an anti-vibration table for placing an object; an air spring for levitating and supporting and positioning the anti-vibration table; and an electromagnetic actuator for controlling vibration of the anti-vibration table. And a second control circuit for controlling the electromagnetic actuator separately provided.   2. The vibration isolation device according to claim 1, further comprising an acceleration sensor that detects vibration of the vibration isolation table and a displacement sensor that detects a position of the vibration isolation table, wherein the first control circuit includes: The second control circuit has a function of causing the air spring to control the position of the vibration isolation table using the displacement signal as an input signal, and the second control circuit uses the acceleration signal from the acceleration sensor as an input signal to vibrate the vibration isolation table. A vibration isolator having a function of performing control.   3. The vibration isolation device according to claim 1, wherein both the first control circuit and the second control circuit include a digital control circuit.

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