Anti-vibration apparatus and anti-vibration method thereof

• US 6,170,622 B1
• Filed: 03/06/1998
• Issued: 01/09/2001
• Est. Priority Date: 03/07/1997
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kato, Hiroaki, Mayama, Takehiko, Wakui, Shinji
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US09/035,982
• Time in Patent Office: 1,040 Days
• Field of Search: 188/378, 188/379, 188/380, 188/1.11 E, 188/266.1, 267/136, 267/64.11, 267/64.28, 267/122, 248/550, 248/635, 248/631, 318/632, 318/618, 318/652, 318/568.17, 318/592, 318/611, 318/623, 318/600, 318/448, 108/136, 355/53, 73/149, 73/660-664, 356/400, 364/167.02
• US Class Current: 188/378
• CPC Class Codes: F16F 15/02 Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems F16F15/005 takes precedence ; layered products B32B; suppression of vibration in ships B63; relieving load on bearings, using magnetic means F16C39/06
• CPC Class Codes: F16F 15/027 comprising control arrangements F16F15/0237 takes precedence
• CPC Class Codes: F16F 15/03 using magnetic or electromagnetic means F16F9/53, F16F15/005 take precedence
• CPC Class Codes: G03F 7/709 Vibration, e.g. vibration detection, compensation, suppression or isolation
• CPC Class Codes: G05D 19/02 characterised by the use of electric means

Abstract

An anti-vibration apparatus is equipped with a plurality of active support legs which support an anti-vibration table and which are able to actively operate to control the motion of the anti-vibration table in a horizontal plane. The apparatus is further equipped with a pressure feedback loop for detecting the internal pressure of an air spring provided in each of the plurality of active support legs and for feeding a signal, which is based on the detected internal pressure of the air spring, back to the control system of the anti-vibration apparatus.

Claims

1. An anti-vibration apparatus for eliminating the vibration of an anti-vibration table, said anti-vibration apparatus comprising:

a plurality of active support legs which support said anti-vibration table and which are able to actively operate to control the motion of said anti-vibration table in a horizontal plane;

control means for controlling the operation of said plurality of active support legs; and

a plurality of pressure detecting means for detecting the internal pressures of air springs respectively provided in said plurality of active support legs,

wherein said control means comprises a pressure feedback loop which feeds the signals, which are based on the internal pressures of said air springs detected by said plurality of pressure detecting means, back to a control system of said control means in order to adjust the internal pressures of said air springs according to the detected internal pressures.

2. An anti-vibration apparatus according to claim 1, wherein the air springs provided in each of said plurality of active support legs are a pair of air springs, and further comprising a three-way or four-way type servo valve for supplying or exhausting air, which is a medium for operating the pair of air springs, to or from the air springs, and

said pressure detecting means detects the differential pressure produced in said pair of air springs by the supply or exhaustion of air by said servo valve; and

said pressure feedback loop feeds a signal, which is based on the differential pressure detected by said pressure detecting means, back to the control system of said control means.

3. An anti-vibration apparatus according to claim 2, further comprising:

vibration measuring means for measuring the vibration of said anti-vibration table; and

position measuring means for measuring the position of said anti-vibration table,

wherein said control means comprises an acceleration feedback loop for feeding a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result given by said vibration measuring means, back to the control system of said control means, and a position feedback loop for feeding a signal, which corresponds to the position of said anti-vibration table measured by said position measuring means, back to the control system of said control means.

4. An anti-vibration apparatus according to claim 2, wherein said acceleration feedback loop and said position feedback loop are decoupling control schemes based on the motional mode of said anti-vibration table, and

said pressure feedback loop is provided separately for each of said plurality of active support legs.

5. An anti-vibration apparatus according to claim 1, further comprising an exposure apparatus for depositing a predetermined mask pattern on a silicon wafer, said exposure apparatus being mounted on said anti-vibration table.

6. An anti-vibration apparatus according to claim 1, wherein the air springs provided in each of said plurality of active support legs are a pair of air springs, and further comprising a three-way type servo valve for supplying or exhausting air, which is a medium for operating the pair of air springs, to or from the air springs;

said pressure detecting means detects the pressure produced in said pair of air springs when air is supplied or exhausted by said servo valve; and

said pressure feedback loop feeds a signal, which corresponds to the differential pressure which is produced between said pair of air springs and which has been calculated according to the pressures which are respectively generated in said pair of air springs and which have been detected by said pressure detecting means, back to the control system of said control means.

7. An anti-vibration apparatus according to claim 6, further comprising:

vibration measuring means for measuring the vibration of said anti-vibration table; and

position measuring means for measuring the position of said anti-vibration table,

wherein said control means further comprises an acceleration feedback loop for feeding a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result given by said vibration measuring means, back to the control system of said control means, and a position feedback loop for feeding a signal, which corresponds to the position of said anti-vibration table measured by said position measuring means, back to the control system of said control means.

8. An anti-vibration apparatus according to claim 1, wherein the air springs provided in each of said plurality of active support legs are a pair of air springs, and further comprising a three-way type servo valve for supplying or exhausting air, which is a medium for operating the pair of air springs, to or from the air springs,

said pressure detecting means detects the pressure produced in said pair of air springs when air is supplied or exhausted by said servo valve, and

said pressure feedback loop is provided for each air spring of said pair of air springs and a signal, which corresponds to the pressure generated at each of said pair of air springs and detected by said pressure detecting means, is fed back to the control system of said control means by the pressure feedback loop.

9. An anti-vibration apparatus according to claim 8, further comprising:

vibration measuring means for measuring the vibration of said anti-vibration table; and

position measuring means for measuring the position of said anti-vibration table,

wherein said control means further comprises an acceleration feedback loop for feeding a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result given by said vibration measuring means, back to the control system of said control means, and a position feedback loop for feeding a signal, which corresponds to the position of said anti-vibration table measured by said position measuring means, back to the control system of said control means.

10. An anti-vibration apparatus according to claim 9, wherein, in the control system of said control means, said signal corresponding to the acceleration and said signal corresponding to the position are not applied to either one of said pressure feedback loops provided for each air spring of said pair of air springs.

11. An anti-vibration apparatus for eliminating the vibration of an anti-vibration table, said anti-vibration apparatus comprising:

a plurality of active support legs which support said anti-vibration table and which are able to actively operate to control the motion of said anti-vibration table in a horizontal plane;

control means for controlling the operation of said plurality of active support legs; and

a plurality of load measuring means for detecting the load generated by the operation of air springs respectively provided in said plurality of active support legs,

wherein said control means comprises a load feedback loop for feeding the signals, which correspond to the loads measured by said plurality of load measuring means, to a control system of said control means in order to adjust the loads produced by the operation of said air springs according to the detected loads.

12. An anti-vibration apparatus according to claim 11, wherein the air springs provided in each of said plurality of active support legs are a pair of air springs, and further comprising a three-way or four-way type servo valve for supplying or exhausting air, which is a medium for operating the pair of air springs, to or from the air springs,

said load measuring means detects the load produced by the operation of the pair of air springs for each of said pair of air springs, and

said load feedback loop feeds a signal, which corresponds to the load measured by said load measuring means, back to the control system of said control means.

13. An anti-vibration apparatus according to claim 12, further comprising:

vibration measuring means for measuring the vibration of said anti-vibration table; and

position measuring means for measuring the position of said anti-vibration table,

wherein said control means further comprising an acceleration feedback loop for feeding a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result given by said vibration measuring means, back to the control system of said control means, and a position feedback loop for feeding a signal, which corresponds to the position of said anti-vibration table measured by said position measuring means, back to the control system of said control means.

14. An anti-vibration apparatus according to claim 11, wherein said load measuring means is a load sensor.

15. An anti-vibration apparatus according to claim 13, wherein said acceleration feedback loop and said position feedback loop are decoupling control schemes based on the motional mode of said anti-vibration table, and

said load feedback loop is provided separately for each of said plurality of active support legs.

16. An anti-vibration apparatus according to claim 11, further comprising an exposure apparatus for depositing a predetermined mask pattern on a silicon wafer, said exposure apparatus being mounted on said anti-vibration table.

17. An anti-vibration apparatus for eliminating the vibration of an anti-vibration table, said anti-vibration apparatus comprising:

a plurality of active support legs which support said anti-vibration table and which can be actively operated by an air spring actuator to control the motion of said anti-vibration table in a horizontal plane;

control means for controlling the operation of said plurality of active support legs; and

pressurizing force measuring means for measuring the pressurizing force of said air spring actuator,

wherein said control means comprises a pressurizing force feedback loop for feeding a signal, which corresponds to the pressurizing force measured by said pressurizing force measuring means, back to a control system of said control means in order to adjust the pressurizing force of said air spring actuator according to the measured pressurizing force.

18. An anti-vibration apparatus according to claim 17, further comprising:

vibration measuring means for measuring the vibration of said anti-vibration table; and

position measuring means for measuring the position of said anti-vibration table,

wherein said control means comprises an acceleration feedback loop for feeding a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result given by said vibration measuring means, back to the control system of said control means, and a position feedback loop for feeding a signal, which corresponds to the position of said anti-vibration table measured by said position measuring means, back to the control system of said control means, and

said control means imparts damping to said anti-vibration table according to said signal based on acceleration and carries out control so as to place said anti-vibration table at a predetermined position according to said signal based on position.

19. An anti-vibration apparatus according to claim 18, wherein said acceleration feedback loop and said position feedback loop are decoupling control schemes based on the motional mode of said anti-vibration table, and

said pressurizing force feedback loop is provided separately for said air spring actuator.

20. An anti-vibration apparatus according to claim 18, wherein said pressurizing force measuring means is pressure measuring means for measuring the internal pressure of said air spring actuator,

said pressurizing force feedback loop is a pressure feedback system which negatively feeds a signal, which corresponds to the internal pressure of said air spring actuator detected by said pressure measuring means, back to a section preceding a voltage-current converter which drives said air spring actuator, and

further comprising a PI compensator which has a zero for canceling the pole of the first-order lag of the pressure feedback system provided at a section preceding said pressure feedback system.

21. An anti-vibration apparatus according to claim 18, wherein said pressurizing force measuring means is pressure measuring means for measuring the load generated by the operation of said air spring actuator,

said pressurizing force feedback loop is a pressure feedback system which negatively feeds a signal, which corresponds to the load detected by said pressure measuring means, back to a section preceding a voltage-current converter which drives said air spring actuator, and

further comprising a PI compensator which has a zero for canceling the pole of the first-order lag of the pressure feedback system provided at a section preceding said pressure feedback system.

22. An anti-vibration apparatus according to claim 18, wherein said pressurizing force measuring means is pressure measuring means for measuring the internal pressure of said air spring actuator,

said pressurizing force feedback loop is a pressure feedback system for supplying an error signal, which is obtained by comparing a signal corresponding to the internal pressure of said air spring actuator detected by said pressure measuring means with a predetermined control signal, to a voltage-current converter, which drives said air spring actuator, via a PI compensator, and

in the pressure feedback system, the zero of said PI compensator is set so that it cancels the pole exhibiting the first-order lag frequency characteristic from said voltage-current converter to said pressure measuring means.

23. An anti-vibration apparatus according to claim 18, wherein said pressurizing force measuring means is load measuring means for measuring the load generated by the operation of said air spring actuator,

said pressurizing force feedback loop is a load feedback system for supplying an error signal, which is obtained by comparing a signal corresponding to the load detected by said pressure measuring means with a predetermined control signal, to a voltage-current converter, which drives said air spring actuator, via a PI compensator, and

in the load feedback system, the zero of said PI compensator is set so that it cancels the pole exhibiting the first-order lag frequency characteristic from said voltage-current converter to said load measuring means.

24. An anti-vibration apparatus according to claim 18, wherein, when said PI compensator is provided at the section preceding the junction point of said pressurizing force feedback loop and said acceleration feedback loop and/or said position feedback loop,

a position error compensator for said position feedback loop is a PI compensator or a gain compensator.

25. An anti-vibration apparatus according to claim 17, further comprising:

floor vibration measuring means for measuring the vibration of the floor on which said anti-vibration apparatus is installed;

a floor vibration feedforward compensator which issues a feedforward signal to the control system of said control means according to a measurement result given by said floor vibration measuring means; and

a reaction force feedforward compensator which issues a feedforward signal, which is based on the reaction force generated by the driving force of an apparatus mounted on said anti-vibration table, to the control system of said control means in accordance with a drive signal of said apparatus,

wherein the feedforward signals issued by said floor vibration feedforward compensator and said reaction force feedforward compensator are applied to the section preceding said pressurizing force feedback loop in the control system of said control means.

26. An anti-vibration apparatus according to claim 25, wherein said floor vibration feedforward compensator includes PI compensators connected in a double-stage cascade,

the zero of one of the PI compensators is set to cancel the pole acting as the first-order lag system of said pressurizing force feedback loop, and

the zero of the other PI compensator is set to −

K/C where C denotes the viscosity damping coefficient of said anti-vibration table, and K denotes the spring constant of said air spring actuator.

27. An anti-vibration apparatus according to claim 25, wherein said floor vibration feedforward compensator includes an integrator and a PI compensator in a cascade connection, and

the zero of the PI compensator is set so as to cancel the pole acting as the first-order lag system of said pressurizing force feedback loop.

28. An anti-vibration apparatus according to claim 25, wherein said reaction force feedforward compensator is a phase lead compensator, and the zero of the phase lead compensator is set to cancel the pole acting as the first-order lag system of said pressurizing force feedback loop, and the pole of the phase lead compensator is set to have a break point in a high-frequency zone.

29. An anti-vibration method for an anti-vibration apparatus for eliminating the vibration of an anti-vibration table by controlling the motion of a plurality of active support legs, which support said anti-vibration table and which are able to actively operate, in a horizontal plane, said anti-vibration method comprising:

a pressure detecting step for detecting the internal pressures of the air springs provided respectively in said plurality of active support legs; and

a control step for feeding the signals, which are based on the internal pressures of said air springs detected in said pressure detection step, back to a control system of said anti-vibration apparatus in order to adjust the internal pressures of said air springs according to the detected internal pressures.

30. An anti-vibration method according to claim 29, wherein, when the air springs provided in each of said plurality of active support legs are a pair of air springs, and there is provided a three-way or four-way type servo valve for supplying or exhausting air, which is a medium for operating the pair of air springs, to or from the air springs,

said pressure detecting step detects the differential pressure produced in said pair of air springs when air is supplied or exhausted by said servo valve, and

said control step feeds a signal, which is based on the differential pressure detected in said pressure detecting step, back to the control system of said anti-vibration apparatus.

31. An anti-vibration method according to claim 30, further comprising:

a vibration measurement step for measuring the vibration of said anti-vibration table; and

a position measuring step for measuring the position of said anti-vibration table,

wherein said control step feeds a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result obtained in said vibration measurement step and a signal, which corresponds to the position of said anti-vibration table measured in said position measurement step, back to the control system of said anti-vibration apparatus.

32. An anti-vibration method according to claim 29, wherein, when the air springs provided in each of said plurality of active support legs are a pair of air springs, and there is provided a three-way type servo valve for supplying or exhausting air, which is a medium for operating the pair of air springs, to or from the air springs,

said pressure detection step detects the pressure produced in said pair of air springs when air is supplied or exhausted by said servo valve, and

said control step feeds a signal, which corresponds to the differential pressure which is produced between said pair of air springs and which has been calculated according to the pressures which are respectively generated at said pair of air springs and which have been detected in said pressure detection step, back to the control system of said anti-vibration apparatus.

33. An anti-vibration method according to claim 32, further comprising:

a vibration measuring step for measuring the vibration of said anti-vibration table; and

a position measuring step for measuring the position of said anti-vibration table,

wherein said control step feeds a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result given in said vibration measurement step, and a signal, which corresponds to the position of said anti-vibration table measured in said position measurement step, back to the control system of said anti-vibration apparatus.

34. An anti-vibration method according to claim 29, wherein, when the air springs provided in each of said plurality of active support legs are a pair of air springs, and there is provided a three-way type servo valve for supplying or exhausting air, which is a medium for operating the pair of air springs, to or from the air springs,

said pressure detection step detects the pressure produced in said pair of air springs when air is supplied or exhausted by said servo valve, and

said control step feeds a signal, which corresponds to the pressure generated at each of said pair of air springs and detected in said pressure detection step, back to the control system of said anti-vibration apparatus.

35. An anti-vibration method according to claim 34, further comprising:

a vibration measurement step for measuring the vibration of said anti-vibration table; and

a position measurement step for measuring the position of said anti-vibration table,

wherein said control step feeds a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result obtained in said vibration measurement step, and a signal, which corresponds to the position of said anti-vibration table measured in said position measurement step, back to the control system of said anti-vibration apparatus.

36. An anti-vibration method for an anti-vibration apparatus for eliminating the vibration of an anti-vibration table by controlling the motion of a plurality of active support legs, which support said anti-vibration table and which are able to actively operate, in a horizontal plane, said anti-vibration method comprising:

a plurality of load measurement steps for detecting the loads generated by the operation of the air springs provided respectively in said plurality of active support legs; and

a control step for feeding the signals, which are based on the loads measured in said load measurement steps, back to a control system of said anti-vibration apparatus in order to adjust the loads produced by the operation of said air springs according to the detected loads.

37. An anti-vibration method according to claim 36, wherein, when the air springs provided in each of said plurality of active support legs are a pair of air springs, and there is provided a three-way or four-way type servo valve for supplying or exhausting air, which is a medium for operating the pair of air springs, to or from the air springs,

said load measurement steps detect the load produced by the operation of said pair of air springs for each of said air springs, and

said control step feeds a signal, which is based on the load measured in said load measurement step, back to the control system of said anti-vibration apparatus.

38. An anti-vibration method according to claim 37, further comprising:

a vibration measurement step for measuring the vibration of said anti-vibration table; and

a position measuring step for measuring the position of said anti-vibration table,

wherein said control step feeds a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result obtained in said vibration measurement step and a signal, which corresponds to the position of said anti-vibration table measured in said position measurement step, back to the control system of said anti-vibration apparatus.

39. An anti-vibration method for an anti-vibration apparatus for eliminating the vibration of an anti-vibration table by controlling the motion of a plurality of active support legs, which support the anti-vibration table and which can be actively operated by air spring actuators, in a horizontal plane, said anti-vibration method comprising:

a pressurizing force measurement step for measuring the pressurizing forces of said air spring actuators; and

a control step for feeding the signals, which are based on the pressurizing forces measured in said pressurizing force measurement step, to a control system of said anti-vibration apparatus in order to adjust the pressurizing forces of said air spring actuators according to the measured pressurizing forces.

40. An anti-vibration method according to claim 39, further comprising:

a vibration measurement step for measuring the vibration of said anti-vibration table; and

a position measurement step for measuring the position of said anti-vibration table,

wherein said control step feeds a signal, which corresponds to the acceleration of the vibration of said anti-vibration table which is based on the measurement result obtained in said vibration measurement step, back to the control system of said anti-vibration apparatus so as to impart damping to said anti-vibration table in accordance with the signal based on the acceleration, and

feeds a signal, which corresponds to the position of said anti-vibration table measured in said position measurement step, back to the control system of said anti-vibration apparatus so as to place said anti-vibration table at a predetermined position in accordance with the signal based on the position.

41. An anti-vibration apparatus comprising:

an anti-vibration table;

a plurality of air springs which support said anti-vibration table and which are able to actively operate by air being supplied to or exhausted from said air springs;

a plurality of position detectors which detect a position of said anti-vibration table;

a plurality of vibration detectors which detect vibration of said anti-vibration table;

a plurality of pressure detectors which detect internal pressures of said air springs; and

a controller which controls, for eliminating the vibration of said anti-vibration table, the operation of said air springs on the basis of output signals from said position detectors, vibration detectors and pressure detectors.

42. An anti-vibration apparatus comprising:

an anti-vibration table;

a plurality of air springs which support said anti-vibration table and which are able to actively operate by air being supplied to or exhausted from said air springs;

a plurality of position detectors which detect a position of said anti-vibration table;

a plurality of vibration detectors which detect vibration of said anti-vibration table;

a plurality of load detectors which detect a load generated by the operation of said air springs; and

a controller which controls, for eliminating the vibration of said anti-vibration table, the operation of said air springs on the basis of output signals from said position detectors, vibration detectors and load detectors.

43. An anti-vibration apparatus comprising:

an anti-vibration table;

a plurality of air springs which support said anti-vibration table and which are able to actively operate by air being supplied to or exhausted from said air springs;

a plurality of position detectors which detect a position of said anti-vibration table;

a plurality of vibration detectors which detect vibration ofsaid anti-vibration table;

a plurality of pressurizing force detectors which detect a pressurizing force of said air spring; and

a controller which controls, for eliminating the vibration of said anti-vibration table, the operation of said air springs on the basis of output signals from said position detectors, vibration detectors and pressurizing force detectors.

44. An anti-vibration method for an anti-vibration apparatus for eliminating vibration of an anti-vibration table by controlling the motion of a plurality of air springs, which support said anti-vibration table and which are able to actively operate by air being supplied to or exhausted from the air springs, said anti-vibration method comprisings:

a position detecting step for detecting a position of the anti-vibration table;

a vibration detecting step for detecting vibration of the anti-vibration table;

a pressure detecting step for detecting internal pressures of the air springs; and

a contol step for controlling the operation of the air springs on the basis of results of the detected position of the anti-vibration table, the detected vibration of the anti-vibration table and the detected internal pressures of the air springs.

45. An anti-vibration method for an anti-vibration apparatus for eliminating vibration of an anti-vibration table by controlling the motion of a plurality of air springs, which support the anti-vibration table and which are able to actively operate by air springs, said anti-vibration method comprising:

a position detecting step for detecting a position of the anti vibration table;

a vibration detecting step for detecting vibration of the anti-vibration table;

a load detecting step for detecting a load generated by the operation of the air springs; and

a control step for controlling the operation of the air springs on the basis of results of the detected position of the anti-vibration table, the detected vibration of the anti-vibration table and the detected load of the air springs.

46. An anti-vibration method for an anti-vibration apparatus for eliminating vibration of an anti-vibration table by controlling the motion of a plurality of air springs, which support the anti-vibration table and which are able to actively operate by air being supplied to or exhausted from the air springs, said anti-method comprising:

a position detecting step for detecting a position of the anti-vibration table;

a vibration detecting step for detecting vibration of the anti-vibration table;

a pressurizing force detecting step for detecting a pressurizing force of the air springs; and

a control step for controlling the operation of the air springs on the basis of results of the detected position of the anti-vibration table, the detected vibration of the anti-vibration table and the detected pressurizing force of the air springs.