KR20060036938A - Anti-vibration unit for actively controlling vibration and its control system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dustproof unit for actively controlling vibration and a control system thereof, comprising: a chamber in which a support plate, a shaft, and an air inlet are formed in a dustproof unit that supports a vibration table and controls vibration by using an air spring. Viscous fluid, piston, rubber, one end of the wall and chamber wall below the air inlet, sensor dock that is connected to the base plate, acceleration sensor, position sensor, and air inlet that contact the sensor dock to measure acceleration and position respectively. Connected inlet valve module for supplying compressed air, exhaust valve module for discharging compressed air, controller for receiving control signal and outputting control signal from acceleration sensor and position sensor, receiving and control signal from controller It characterized in that it comprises a valve driver for controlling, actively curses the vibration component It is possible to control from the frequency band, and to keep the vibration table horizontal and constant at all times, so that the machined product can be precision and the measurement can be made precisely.

Dustproof, Dustproof Control, Air Spring, Dustproof Table, Oil Damper, Active Control

Description

A vibration control unit for actively controlling vibration and a control system thereof             

1 is a cross-sectional view showing a dustproof unit of a passive vibration control method using a conventional air spring,

2 is a cross-sectional view showing a dustproof unit of the present invention, each unit supporting a dustproof table;

3 is a dustproof circuit diagram schematically showing a dustproof unit of the present invention and a dustproof circuit for controlling the same;

4 is a block diagram schematically showing the flow of an active vibration control system of the present invention;

FIG. 5 is a view illustrating a part of an ON / OFF control process for a time of a solenoid valve in an anti-vibration circuit for active vibration control according to the present invention. FIG.

6 is a plan view showing a dustproof table supported by the dustproof units of the present invention.

※ Brief description of the reference numerals

20: air spring

21: support plate 22: shaft

22a: moving plate 23: chamber wall

23a: air inlet 24: viscous fluid

25: piston 26: elastic rubber

27: sensor dock 28: acceleration sensor

29: position sensor 30: micro controller

30a: measuring unit 30b: control unit

30c: A / D converter 30d: D / A converter

30e: Input port 30f: Output port

31: valve actuator

321, 322, 323, 324: Solenoid Valve

32a: inlet valve module 32b: exhaust valve module

33: speed control valve

The present invention relates to a dustproof unit and a control method thereof, each unit supporting a dustproof table, which is one of infrastructures such as a precision measuring device, a precision machine tool, especially a semiconductor manufacturing equipment, which requires precise measurement or precise operation. In order to prevent the vibration factors from the outside from affecting the precision measuring device or processing machine installed on the dustproof table, the required precision measurement and processing can be performed. In addition, the present invention relates to an anti-vibration unit and a control system for actively controlling vibration, which can attenuate external vibrations to a low frequency band, and further, can keep the level of the vibration table continuously at a desired position.

Hereinafter, with reference to the accompanying drawings looks at the configuration, operation and problems of the conventional dustproof unit.

1 is a cross-sectional view showing a dustproof unit of a passive vibration control method using a conventional air spring.

As shown, a dustproof unit which is conventionally used to hold it at various places (at least three or more) at the bottom of the dustproof table 19 includes a support plate 10 which is in contact with the dustproof table 10 and the bottom of the support plate. A shaft 11 coupled to the center, an upper cover 12 through which the shaft is in close contact with the center, an upper movable plate 13a and a lower movable plate 13b coupled to the lower portion of the shaft and bolted to each other, and air Intermediate cylinder 14 formed on one side of the entrance 14a, the outer periphery is sandwiched between the upper cover and the intermediate cylinder is bolted and fixed position, the central portion is sandwiched between the upper and lower movable plates bolted together Elastic rubber (15) that moves in accordance with the air pressure, the outer periphery is fixed to the position below the air inlet of the inner surface of the intermediate cylinder, the partition 16 is formed with an orifice (16a) in the center, bolted to the intermediate cylinder and ground The lower plate 17 which is in contact with the ground bottom, and one end thereof is in contact with the lower surface of the dustproof table, and the lever 18a which is moved together with the movement of the dustproof table is connected to the upper part and connected to the air inlet. It can be seen that it is composed of a mechanical valve (18). (The orifice is a normal use, not shown separately.)

On the other hand, the mechanical valve 18 is a three-port three-position compressor (18b) is connected, the A port is a port connected to the air spring where the compressed air in and out, the P port is a compressed air with a constant force in the compressor Is the port to which is supplied, and the R port is the port to discharge the compressed air inside the air spring to the atmosphere.

Hereinafter, it will be described how to passively absorb the vibration when the vibration or the load according to the vibration is applied to the conventional dustproof unit having the above-described configuration.

The supporting plate 10 may be a portion of which the upper surface is in contact with the lower surface of the dustproof table and supports a load by a mechanical device or the like placed on the dustproof table.

The shaft 11 is coupled to the center of the base plate, penetrates the center of the upper cover 12, and the upper movable plate 13a and the lower movable plate 13b are coupled to the lower side, the upper movable plate 13a The center portion of the elastic rubber 15 is inserted and bolted together between the bottom and the lower movable plate 13b. When a load is applied to the support plate, the load is transmitted to the shaft and the upper and lower movable plates, and consequently, the elastic This results in the movement of the central portion of the rubber. (The outer circumference of the elastic rubber is sandwiched between the upper cover and the intermediate cylinder and bolted together to fix the position.)

On the other hand, an air inlet 14a is formed on one side of the intermediate cylinder 14 to be connected to a mechanical valve 18 at a three-port three position, and its shape is fixed to the position below the air inlet on the inner surface, unlike elastic rubber. The outer circumference of the partition wall 16 is coupled and fixed, and the movement of the central portion of the elastic rubber changes the volume of the space between the partition wall and the elastic rubber, and accordingly, the space between the partition wall and the elastic rubber (hereinafter, 'the upper chamber Will cause fluctuations in the air pressure of the compressed air. In addition, another chamber (hereinafter referred to as a 'lower chamber') is present between the lower plate and the partition wall.

The fluctuation of the air pressure causes compressed air to enter and exit the two chambers through an orifice 16a formed at the center of the partition wall, and at the same time, an air inlet 14a is provided on the side of the upper chamber, that is, on one side of the intermediate cylinder. And a mechanical valve 18 is connected to the air inlet, and the compressed air in the upper chamber is discharged to the atmosphere (when the lever is raised) through the air inlet to discharge the air into the atmosphere (when the lever is raised). Can be maintained at a constant air pressure, resulting in vibration control by absorbing vibrations accordingly. (As such, it is also commonly called air spring.)

That is, when the lower surface of the dustproof table 19 descends, one end of the lever 18a is pressed and the P port and the A port connected to the compressor 18b are interconnected to supply compressed air compressed from the compressor to the air spring. do. On the contrary, when the lower surface of the dustproof table rises, the lever 18a is lifted upward, so that the A port and the R port of the mechanical valve are released into the air. In a certain range, the compressed air is maintained at a neutral position, that is, the three ports are shorted to each other.

However, the conventional dustproof unit and thus the dustproof table as described above has a problem that it is impossible to control the vibration of the low frequency band.

That is, in order to control the vibration from the outside, by using the compressibility of the compressed air supplied to the air spring, the vibration is passively absorbed and controlled only within a certain range by a mechanical valve, so the vibration of the high frequency band is caused by the compressibility of the air. Absorption control was possible, but there was a problem that there is no countermeasure in the case of vibration in the low frequency band, in particular, the amplitude is small. In other words, to suppress the vibration of the low frequency band is limited by the mechanical valve, the control system that can be actively adjusted to the desired position by feedback control by measuring the position of the vibration table by the electrical signal, the reality is also urgent The need to control vibrations in the low frequency band has been increasing.

In addition, the use of a control method by a mechanical valve, there is a problem in that the level of the inclination of the vibration table generated by the mechanical motion on the vibration table or to keep the desired target position constantly constant. .

The present invention has been made to solve the above problems, the object of the present invention is to ensure the precise measurement, processing, etc. required by the vibration factor from the outside does not affect the precision measuring device or processing machine installed on the dustproof table, etc. In order to achieve this, it is possible to passively attenuate external vibration not only to the high frequency band but also to the low frequency band, in addition to passively absorbing external vibration, and also to keep the level of the dustproof table constantly at a desired position. The present invention provides an anti-vibration unit that actively controls vibration and a control system thereof.

In order to achieve the above object, the present invention provides a dustproof unit for supporting a vibration table and controlling vibration by using an air spring (20), comprising: a support plate (21) in contact with the dustproof table; A shaft 22 having an upper portion coupled to a lower center of the support plate, and a movable plate 22a formed at a lower portion thereof; A chamber wall (23) formed in a cylindrical shape and having a shaft penetrating close to the center of the upper surface and having an air inlet (23a) formed on a cylindrical side surface; A viscous fluid 24 contained below the air inlet of the chamber wall; An upper portion bolted to the moving plate and a lower portion of the piston submerged in the viscous fluid; An outer circumference of the chamber wall is fixed to the inner surface of the upper portion of the air outlet by bolting, and the central portion is sandwiched between the moving plate and the piston and is bolted together to move in accordance with the air pressure; A sensor dock 27 whose one end is coupled to the support plate; An acceleration sensor 28 and a position sensor 29 contacting the sensor dock to measure acceleration and position, respectively; An intake valve module 32a connected to the air inlet for supplying compressed air and an exhaust valve module 32b for discharging the compressed air; A controller 30 which receives signals of the acceleration sensor and the position sensor and emits a control signal; It characterized in that it comprises a valve driver 31 for controlling the intake and exhaust valve module in response to the control signal of the controller.

Hereinafter, with reference to the accompanying drawings will be described in more detail the configuration and operation of the present invention.

Fig. 2 is a sectional view showing the air spring 2 in the dustproof unit of the present invention which is each unit supporting the dustproof table.

As shown, the dustproof unit of the present invention is used to hold it at various places (at least three or more places) at the bottom of the dustproof table, and the air spring 20 is roughly provided with a support plate 21 in contact with the dustproof table, The upper portion is coupled to the lower center of the support plate, and the lower plate 22 has a movable plate 22a formed therein, and a cylindrical surface is formed in the center of the upper surface. Chamber wall 23, a viscous fluid 24 contained below the air inlet of the chamber wall, the upper part is bolted to the moving plate and the lower part of the piston 25 is immersed in the viscous fluid, the outer air of the chamber wall Elastic rubber 26 is fixed to the inner surface of the upper part of the entrance and exit, the central portion is sandwiched between the moving plate and the upper piston and bolted together to move in accordance with the air pressure, one end of the support plate Sensor dock (27) is coupled, are brought into contact with the sensor dock can be seen that consists of an acceleration sensor 28, position sensor 29 to measure the respective accelerations and positions.

When the vibration is applied to the support plate 21, the vibration becomes the vibration of the sensor dock 27 whose one end is coupled to the support plate, and is positioned by the acceleration sensor 28 and the position sensor 29 which are in contact with the sensor dock. Change and acceleration are measured.

In addition, the vibration applied to the support plate is the vibration of the shaft 22, the moving plate 22a is formed in the lower part of the shaft, the piston upper part is bolted to the moving plate, the elastic rubber is sandwiched between the bolted together The elastic bar causes movement and deformation of the central portion of the elastic rubber. (The outer circumference of the elastic rubber is bolted and fixed to the inner surface of the upper portion of the air inlet of the chamber wall.)

The movement and deformation of the elastic rubber changes the volume of the space between the viscous fluid and the elastic rubber (hereinafter, referred to as a "chamber"), causing variation in air pressure in the chamber, and at the same time, the piston 25 contained in the viscous fluid. It causes the movement of the lower part.

The lower part of the piston is installed to be locked to a sufficient depth inside the viscous fluid, the lower part of the piston acts as a damping function for controlling the vibration because the vertical movement is made in the viscous fluid. In other words, it has the function of an oil damper to sufficiently absorb vibrations even against low frequency vibrations.

As a result, the anti-vibration unit of the present invention is not simply using a conventional air spring method, but is sufficiently absorbed by an air spring having the function of an oil damper, and actively used by a control system to be described later using a sensor. By controlling the vibration, it is possible to control even when the amplitude of the low frequency is small, and further, to adjust it to the desired position and horizontal.

The air inlet (23a) may be installed on one side, but in order to maximize the response of the dustproof unit, the compressed air flows into one side and the compressed air inside the air spring is discharged from the opposite side to the length of the pneumatic pipe. This can reduce the responsiveness of the response.

FIG. 3 is a dustproof circuit diagram schematically showing a dustproof unit of the present invention and a dustproof circuit for controlling it, and FIG. 4 is a block diagram schematically showing the flow of an active vibration control system of the present invention. Hereinafter, it demonstrates in order.

(1) The acceleration and the position are measured by the acceleration sensor 28 and the position sensor 29 installed in the dustproof unit.

② The measured signal goes through the signal processor and then the A / D converter converts the acceleration and displacement signals into digital values. The A / D converter 30c, the D / A converter 30d, the input / output ports 30e and 30f, etc., are constructed on the controller 30 using the microprocessor, in addition to the measuring unit 30a and the control unit 30b. It is.

③ The controller 30 using the microprocessor recognizes the converted digital value (acceleration information and displacement information), and the target displacement and vibration values set by the user in advance are input to the control program. The vibration value and the displacement error are generated by comparing the measured value recognized from the sensor with the value (controller measuring part, 30a).

④ When the generated error value reaches the target value set in advance by the user, the measurement is performed by the sensor again to continuously reach the target value, and the generated error value is the target value preset by the user. If it is not reached, the control unit of the controller calculates the opening time and closing time of the solenoid valve corresponding to the error value, and sends the control signal to the valve driver through the D / A converter 30d and the output port 30f. , 31) (controller control unit, 30b).

On the other hand, the control unit 30b sends a measurement signal to the sensor via the D / A converter and the output port to measure the sensor after the sampling time St, separately from the control signal for opening / closing the solenoid valve.

⑤ The time calculated by the control part is transmitted to the valve driver 31 through the D / A converter and the output port, and the valve driver sends the signal of the input or exhaust to each solenoid valve according to the input or exhaust. Send to control the solenoid valve.

Compressed air is input from the P port of the solenoid valve and discharged to the A port, and the flow rate of the air can be controlled by adjusting the effective cross-sectional area of the speed control valve 33.

In the case of using two solenoid valves, a fixed error range is set, and if the error is large, the solenoid valves 321 and 323 on the side where the cross-sectional area of the speed control valve is largely operated are operated. A program is prepared to operate the solenoid valves 322 and 324 on the side of the regulated speed control valve to control the supply and discharge flow rates of air.

On the other hand, the intake valve module (32a) composed of two solenoid valves (323, 324) configured on the supply source side of the compressed air serves to supply compressed air to the air spring, the other two solenoid valves (321, Exhaust valve module 32b consisting of 322 is used to discharge the compressed air inside the air spring to the atmosphere. Power is connected to the valve driver 33, and a compressor is connected to the intake valve module 32a.

FIG. 5 is a view illustrating a part of an ON / OFF control process with respect to time of a solenoid valve in an anti-vibration circuit for active vibration control according to the present invention.

In the drawing, St denotes a time until the time when the signal input from the sensor is input to the microprocessor controller 30 and the error is calculated to output the signal to control the solenoid valve 32, that is, the sampling time, δt ₁ Is the opening time of the solenoid valve and t ₀ means the closing time of the valve.

When the position or acceleration error is set to e, the actual open time δt ₁ of the solenoid valve is calculated as follows.

δt ₁ = e × c

Here, c means a controller.

Next, the closing time t ₀ of a valve is calculated | required with the following formula | equation.

t ₀ = St-δt ₁

The smaller the error is small, the open time of the valve is δt ₁ becomes shorter, the longer the closing time t ₀ of the valve, whereas the larger the larger the error of the valve open time δt ₁ are the longer, the shorter is the time t ₀ of the closed valve.

6 is a plan view showing a dustproof table supported by the dustproof units of the present invention.

As shown, to install the air spring 20 in the dustproof unit at the bottom of the dustproof table 4 at four corners and to control the supply or exhaust flow rate of the compressed air supplied to the air spring 20 or exhausted from the air spring. For this purpose, the modules 32a and 32b of the solenoid valve are installed on the side of the air spring 20 in the dustproof unit.

As the four dustproof units, the vibration component transmitted to the dustproof table is actively controlled to the low frequency band, and the tilt of the dustproof table generated by the mechanical movement on the dustproof table can be corrected to maintain a constant level. It enables position control to maintain a constant height according to the height. That is, the inclination of the dustproof table may be the same as the set height of the user for each of the dustproof units.

In the case of FIG. 6, four or more dustproof units are installed below the dustproof table, or in some cases, three or more dustproof units may be installed within the scope of the present invention.

As described above, the present invention provides a vibration control table equipped with a measuring device and a processing machine that require precise operation and operation, which can actively control the vibration component transmitted from the bottom of the installation surface from the low frequency band, It is configured to keep the level and position of the dustproof table generated from the movement of the mechanical device installed at all times constant. Therefore, it is possible to refine the machined product by the mechanical device using the active dustproof table and to make accurate measurement. Has the effect of enabling it.

In addition, since the vibration of the high frequency band can be controlled by the compressibility of the air using the air spring, the vibration is measured using the controller to actively control the vibration by measuring the vibration using the acceleration sensor to control the vibration of the low frequency band. By generating the error by comparing the target value of the vibration with the measured value and controlling the opening and closing time of the solenoid valve, it controls the flow rate of the compressed air supplied to the air spring to actively suppress the vibration in the low frequency band. It has an effect that can be controlled by.

In addition, when the tilt of the table due to the mechanical operation on the dustproof table, the deviation of the measured value measured from the position sensor of each dustproof unit is calculated to calculate the slope of the dustproof table and generate an error by comparing with the target position. By using this to control the compressed air flow rate is supplied or discharged to the air spring has a horizontal and position control capable of maintaining the dustproof table horizontally at the desired height position (level).

Claims (3)

In the dustproof unit for supporting the vibrationproof table and controlling the vibration using the air spring 20, A support plate 21 in contact with the dustproof table; A shaft 22 having an upper portion coupled to a lower center of the support plate, and a movable plate 22a formed at a lower portion thereof; A chamber wall (23) formed in a cylindrical shape and having a shaft penetrating close to the center of the upper surface and having an air inlet (23a) formed on a cylindrical side surface; A viscous fluid 24 contained below the air inlet of the chamber wall; An upper portion bolted to the moving plate and a lower portion of the piston submerged in the viscous fluid; An outer circumference of the chamber wall is fixed to the inner surface of the upper portion of the air outlet by bolting, and the central portion is sandwiched between the moving plate and the piston and is bolted together to move in accordance with the air pressure; A sensor dock 27 whose one end is coupled to the support plate; An acceleration sensor 28 and a position sensor 29 contacting the sensor dock to measure acceleration and position, respectively; An intake valve module 32a connected to the air inlet for supplying compressed air and an exhaust valve module 32b for discharging the compressed air; A controller 30 which receives signals of the acceleration sensor and the position sensor and emits a control signal; And a valve driver (31) for controlling the intake and exhaust valve modules in response to a control signal of the controller. The intake valve module 32a is composed of two solenoid valves 323 and 324 connected to the air inlet and supplying compressed air, and a speed control valve 33 for each of the exhaust valves. The valve module (32b) is an anti-vibration unit for actively controlling vibration, characterized in that consisting of two solenoid valves (321, 322) for discharging the compressed air and a speed control valve (33) for each. The acceleration and position of the air spring 20 is measured by the acceleration sensor 28 and the position sensor 29, The measured signal is passed through a signal processor and then converted into a digital value by an A / D converter (). The controller 30 recognizes the converted digital value and generates an error from the target value set by the user in advance. When the generated error value reaches the target value, the sensor is measured again.If the error value does not reach the target value, the open / close time of the solenoid valve corresponding to the error value is calculated to convert the control signal to the D / A converter (30d). And the valve driver 31 via the output port 30f, Separately, the measurement signal to be measured after the sampling time St is sent to the sensors 28 and 29 through the D / A converter and the output port, In the valve driver 31, an inlet valve module 32a or two outlets of compressed air consisting of two solenoid valves 323 and 324 for supplying compressed air according to intake or exhaust and a speed control valve 33 for each of them. A control system for actively controlling vibration, characterized in that the solenoid valve (321, 322) and the speed control valve (33) for each of the exhaust valve module (32b) consisting of the input or exhaust signal to control.

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