A stiffness-adjustable three-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform

Abstract

The application provides a stiffness-adjustable three-degree-of-freedom ultra-low-frequency quasi-zero stiffness vibration isolation platform, which comprises a base, a vertical plate, a top plate, a support block one and an air spring A, the vertical plate is vertically welded around the top of the base, the support plate is vertically welded at the top middle of the vertical plate, the air spring B is installed at the top middle of the base, the support block two is installed at the top of the air spring B, the air spring C is connected through hinges around the support block two, the flexural beam is connected around the middle of the support block one, the flexible rod is vertically installed at the top middle of the flexural beam, and the top of the flexible rod is connected with the bottom of the top plate. The air spring A and the flexural beam form the first layer of quasi-zero stiffness system, the air spring B and the air spring C form the second layer of quasi-zero stiffness system, the two layers of quasi-zero stiffness system form a series mechanism, the double-layer quasi-zero stiffness system vibration isolation is realized, a wider quasi-zero stiffness vibration isolation band is obtained, and vibration control of 0.1Hz-200Hz can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor special devices, and particularly relates to a stiffness-adjustable three-degree-of-freedom ultra-low-frequency quasi-zero-stiffness vibration isolation platform. BACKGROUND

[0002] At present, the semiconductor industry develops rapidly, the precision requirement of semiconductor production equipment is higher and higher, and the equipment is more and more sensitive to the environment such as micro-vibration. A little micro-vibration will reduce the yield of the equipment, and even make the equipment unable to work normally. Therefore, the isolation of micro-vibration becomes more and more important.

[0003] In order to solve the above problems, in recent years, researchers have found some novel vibration isolation methods based on nonlinear dynamics theory-quasi-zero stiffness vibration isolator. The vibration isolator has the characteristics of high static and low dynamic in system stiffness, that is, when the system bears static load, the vibration isolator has relatively high system stiffness and can provide sufficient supporting force; when the system bears dynamic load, the vibration isolator has relatively low system stiffness, and realizes low-frequency and ultra-low-frequency vibration isolation. However, most of the nonlinear vibration isolators based on the quasi-zero stiffness theory can only realize the vibration reduction of specific controlled objects, and cannot meet the vibration isolation of different objects. In addition, the low stiffness displacement interval of the existing quasi-zero stiffness vibration isolator is relatively narrow, and the stiffness increases obviously with the increase of displacement, the nonlinearity is obviously enhanced, the initial vibration isolation frequency is increased, the vibration isolation frequency band is narrowed, and the low-frequency vibration isolation performance is decreased, thereby affecting the application range of the quasi-zero stiffness vibration isolator. In addition, most of the existing quasi-zero stiffness vibration isolation methods focus on one-way vibration isolation, and the research on multi-degree-of-freedom quasi-zero stiffness vibration isolation is still relatively rare. SUMMARY

[0004] The present application relates to the technical field of semiconductor special devices, and particularly relates to a stiffness-adjustable three-degree-of-freedom ultra-low-frequency quasi-zero-stiffness vibration isolation platform.

[0005] The technical solution of this invention is implemented as follows: A stiffness-adjustable three-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform includes a base, a vertical plate, a top plate, a support block 1, and an air spring A. The vertical plate is vertically welded to the top four sides of the base, and a support plate is vertically welded to the center of the top of the vertical plate. An air spring B is installed in the center of the top of the base, and a support block 2 is installed on top of the air spring B. Air springs C are connected to the support block 2 around its perimeter via hinges. A servo motor is installed on the top of the base and below the support plate. A ball screw is connected to the top of the servo motor, and the top of the ball screw is connected to the bottom of the support plate via a bearing. A ball screw nut is fitted onto the ball screw. The other end of the air spring C is connected to the ball screw nut via a hinge. Air spring A is installed on the top of the support block 2. Air spring A includes an air chamber A, and the top of the air chamber A... A piston A is installed, with its top connected to a gas chamber A via a gas membrane. A push rod is vertically installed inside the piston A, with its top connected to the middle of the bottom of a support block. A buckling beam is connected around the middle of the support block, with a screw connected to the other end of the buckling beam. A flexible rod is vertically installed at the middle of the top of the buckling beam, with its top connected to the bottom of a top plate. The middle of the top of the support block is connected to the middle of the bottom of the top plate via a ball joint. A screw hole is horizontally opened in the middle of the support plate, through which the screw is bolted to the support plate. A vertical voice coil motor is installed inside the gas chamber A and at the bottom of the piston A. Baffles are installed around the middle of the bottom of the top plate. A horizontal voice coil motor is installed on the top of the support plate and outside the baffles. An acceleration sensor is also installed at the bottom of the top plate, and a position sensor and a controller are installed on the top of the support plate.

[0006] Furthermore, the air spring C includes a housing, which is cylindrical in shape. A piston C is installed inside the housing, and the piston C and the lower part of the housing form an air chamber C. A linear bearing is installed on the top of the housing, and a guide rod passing through the linear bearing is installed on the top of the piston C. The guide rod is connected to the support block 2 via a hinge. An air inlet pipe C is installed on one side of the air chamber C, and a pneumatic valve C is installed on the air inlet pipe C.

[0007] Furthermore, the base, top plate, support block one, and support block two are all made of stainless steel plates to form a rectangular structure.

[0008] Furthermore, a handle is vertically mounted on the outer side of the screw.

[0009] Furthermore, an air inlet pipe A is installed on one side of the air chamber A, and a pneumatic valve A is installed on the air inlet pipe A.

[0010] Furthermore, an air intake pipe B is installed on one side of the air spring B, and a pneumatic valve B is installed on the air intake pipe B.

[0011] Furthermore, the controller is connected to the vertical voice coil motor, the horizontal voice coil motor, the acceleration sensor, and the position sensor via cables.

[0012] The beneficial effects of this invention are as follows:

[0013] This invention uses air spring A and a buckling beam to form a first-layer quasi-zero stiffness system, and air spring B and air spring C to form a second-layer quasi-zero stiffness system. The two quasi-zero stiffness systems are connected in series to achieve vibration isolation of the double-layer quasi-zero stiffness system, resulting in a wider quasi-zero stiffness vibration isolation band, which can achieve vibration control from 0.1Hz to 200Hz.

[0014] This invention uses a push rod and an air spring A to form an inverted pendulum mechanism with near-zero stiffness in the horizontal direction. A flexible rod is used for high-frequency vibration reduction in the horizontal direction, and a voice coil motor is used for low-frequency vibration reduction in the horizontal direction, thereby obtaining a large vibration isolation bandwidth in the horizontal direction.

[0015] This invention allows for adjustment of the system's load-bearing capacity to meet the load-bearing and stiffness requirements of different loads by adjusting the air pressure of air springs A and B. The negative stiffness of the buckling beam can be adjusted by using a screw, and the negative stiffness of the inclined air spring C can be adjusted by adjusting the air pressure of air spring C, thereby adjusting the negative stiffness of the entire system and achieving overall system stiffness adjustment to meet the vibration isolation requirements of different loads.

[0016] The vibration isolation platform of this invention can achieve vibration isolation in three degrees of freedom: up and down, left and right, and front and back. It has a wide vibration isolation bandwidth and precise positioning, and can be adapted to different types of precision instruments. The maximum load capacity can reach 3000kg. It has a wide range of applications and strong versatility. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] In the diagram: 1-Base, 2-Vertical plate, 3-Top plate, 4-Support block one, 5-Air spring A, 501-Air chamber A, 502-Piston A, 503-Air film, 504-Push rod, 505-Inlet pipe A, 506-Pneumatic valve A, 6-Support plate, 601-Screw hole, 602-Screw, 603-Handle, 7-Air spring B, 701-Inlet pipe B, 702-Pneumatic valve B, 8-Support block two, 9-Air spring C, 901-Outer shell, 902 - Piston C, 903- Air Chamber C, 904- Linear Bearing, 905- Guide Rod, 906- Inlet Pipe C, 907- Pneumatic Valve C, 10- Servo Motor, 11- Ball Screw, 12- Bearing, 13- Ball Screw Nut, 14- Ball Joint, 15- Bending Beam, 16- Flexible Rod, 17- Vertical Voice Coil Motor, 18- Baffle, 19- Horizontal Voice Coil Motor, 20- Acceleration Sensor, 21- Position Sensor, 22- Controller, 23- Hinge. Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, a stiffness-adjustable three-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform includes a base 1, a vertical plate 2, a top plate 3, a support block 4, and an air spring A5. The vertical plate 2 is vertically welded to the top perimeter of the base 1, and a support plate 6 is vertically welded to the center of the top of the vertical plate 2. An air spring B7 is installed in the center of the top of the base 1, and a support block 8 is installed on top of the air spring B7. Air springs C9 are connected to the support block 8 around its perimeter via hinges 23. A support spring is installed on the top of the base 1 and below the support plate 6. A servo motor 10 is connected to a ball screw 11 at its top. The top of the ball screw 11 is connected to the bottom of the support plate 6 via a bearing 12. A ball screw nut 13 is fitted onto the ball screw 11. The other end of an air spring C9 is connected to the ball screw nut 13 via a hinge 23. An air spring A5 is mounted on the top of the support block 8. The air spring A5 includes an air chamber A501. A piston A502 is mounted on the top of the air chamber A501. The piston A502 is connected to the air chamber A501 via an air film 503. A push rod 504 is vertically mounted inside the piston A502. The top of the push rod 504 is connected to the bottom center of the support block 4. A buckling beam 15 is connected around the center of the support block 4. A screw 602 is connected to the other end of the buckling beam 15. A flexible rod 16 is vertically mounted at the top center of the buckling beam 15. The top of the flexible rod 16 is connected to the bottom of the top plate 3. The top center of the support block 4 is connected to the bottom center of the top plate 3 via a ball joint 14. A screw hole 601 is horizontally opened in the middle of the support plate 6. The screw 602 passes through the screw hole 601 and is bolted to the support plate 6. A vertical voice coil motor 17 is installed inside the air chamber A501 and at the bottom of the piston A502. Baffles 18 are installed in the middle of the bottom of the top plate 3. A horizontal voice coil motor 19 is installed on the top of the support plate 6 and outside the baffles 18. An acceleration sensor 20 is also installed at the bottom of the top plate 3. A position sensor 21 and a controller 22 are also installed on the top of the support plate 6.

[0021] The air spring C9 includes a housing 901, which is cylindrical. A piston C902 is installed inside the housing 901. The piston C902 and the lower part of the housing 901 form an air chamber C903. A linear bearing 904 is installed on the top of the housing 901. A guide rod 905 passing through the linear bearing 904 is installed on the top of the piston C902. The guide rod 905 is connected to the support block 8 via a hinge 23. An air inlet pipe C906 is installed on one side of the air chamber C903. A pneumatic valve C907 is installed on the air inlet pipe C906.

[0022] The base 1, top plate 3, support block 1 4, and support block 2 8 are all made of stainless steel plates in a rectangular structure.

[0023] A handle 603 is vertically mounted on the outer side of the screw 602.

[0024] An air inlet pipe A505 is installed on one side of the air chamber A501, and a pneumatic valve A506 is installed on the air inlet pipe A505.

[0025] An air intake pipe B701 is installed on one side of the air spring B7, and a pneumatic valve B702 is installed on the air intake pipe B701.

[0026] The controller 22 is connected to the vertical voice coil motor 17, the horizontal voice coil motor 19, the acceleration sensor 20, and the position sensor 21 via cables.

[0027] During installation, the precision instrument is mounted on top plate 3. The weight of the precision instrument is supported by air springs A and B connected in series. Based on the weight and stiffness requirements of the precision instrument, the air intake volume of the air intake pipe A is first controlled by pneumatic valve A, thereby controlling the positive stiffness of the internal air pressure adjustment system of air spring A to achieve load-bearing capacity. Simultaneously, the negative stiffness of the buckling beam 15 is adjusted by rotating screw 602 via handle 603, thus achieving a static near-zero stiffness for the parallel positive and negative stiffness system composed of air spring A5 and buckling beam 15. Furthermore, the air intake volume of the air intake pipe B701 is controlled by pneumatic valve B702, thereby controlling the positive stiffness of the internal air pressure adjustment system of air spring B7. Simultaneously, the air intake volume of the air intake pipe C906 is controlled by the pneumatic valve C907, thereby controlling the negative stiffness of the internal air pressure adjustment system of the air spring C9. This allows the parallel positive and negative stiffness system composed of air spring B7 and air spring C9 to achieve static quasi-zero stiffness. The air spring C9 is in a diagonal tie rod state, and can be driven by the servo motor 10 to rotate the ball screw 11, thereby driving the ball screw nut 13 to move up and down, adjusting the diagonal angle of the air spring C, further adjusting the negative stiffness of the air spring C, and better achieving the static quasi-zero stiffness of the system. The entire device system presents a double-layer static quasi-zero stiffness state in the vertical direction, obtaining a wider quasi-zero stiffness range.

[0028] During operation, the precision instrument generates vibrations. These vibration signals are collected by the accelerometer 20 and position sensor 21, and then transmitted to the controller 22. For vertical high-frequency vibration sources, vibration isolation is achieved first through a first-layer parallel system of positive and negative stiffness, consisting of a positive stiffness air spring A5 and a negative stiffness buckling beam 15. Simultaneously, further vibration reduction is achieved through a second-layer parallel system of positive and negative stiffness, consisting of a positive stiffness air spring B and a negative stiffness air spring C. These parallel systems on both sides form a series mechanism, achieving a wider quasi-zero stiffness vibration isolation bandwidth. For vertical low-frequency vibration sources, low-frequency vibration isolation is mainly achieved by controlling the vertical voice coil motor 17 via the controller 22. For horizontal high-frequency vibration sources, high-frequency vibration isolation is achieved through the flexible rod 16; for horizontal low-frequency vibration sources, low-frequency vibration isolation is achieved by controlling the horizontal voice coil motor 19 via the controller 22.

[0029] The vibration isolation platform can achieve vibration isolation in three directions: vertical, front-back, and left-right.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A stiffness-adjustable three-degree-of-freedom ultra-low-frequency quasi-zero-stiffness vibration isolation platform comprising a base, a vertical plate, a top plate, a support block one and an air spring A, characterized in that, The vertical plate is vertically welded around the top of the base, a support plate is vertically welded in the middle of the top of the vertical plate, an air spring B is installed in the middle of the top of the base, a support block two is installed on the top of the air spring B and connected with the air spring C through a hinge around, the air spring C comprises a shell, the shell is cylindrical, a piston C is installed inside the shell, the piston C and the lower part of the shell form a gas chamber C, a linear bearing is installed on the top of the shell, a guide rod is installed on the top of the piston C and passes through the linear bearing, the guide rod is connected with the support block two through a hinge, an air inlet pipe C is installed on one side of the gas chamber C, a pneumatic valve C is installed on the air inlet pipe C, a servo motor is installed below the top of the base and the support plate, a ball screw is connected on the top of the servo motor, the ball screw is connected with the bottom of the support plate through a bearing, a ball screw nut is sleeved on the ball screw, the air spring C is connected with the ball screw nut through a hinge on the other end, an air spring A is installed on the top of the support block two, the air spring A comprises a gas chamber A, a piston A is installed on the top of the gas chamber A, the piston A is connected with the gas chamber A through an air film on the top, a push rod is vertically installed inside the piston A, the push rod is connected with the middle of the bottom of the support block one on the top, a flexure beam is connected around the middle of the support block one, a screw rod is connected on the other end of the flexure beam, a flexible rod is vertically installed in the middle of the top of the flexure beam, the flexible rod is connected with the bottom of the top plate on the top, the support block one is connected with the middle of the bottom of the top plate through a ball hinge in the middle of the top, a screw hole is horizontally formed upwards in the middle of the support plate, the screw rod is bolted and fixed with the support plate through the screw hole, a handle is vertically installed on the outside of the screw rod, a vertical voice coil motor is installed inside the gas chamber A and at the bottom of the piston A, a baffle is installed in the middle around the bottom of the top plate, a horizontal voice coil motor is installed on the top of the support plate and outside the baffle, an acceleration sensor is also installed on the bottom of the top plate, a position sensor and a controller are also installed on the top of the support plate.

2. The stiffness-adjustable three-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that, The base, the top plate, the support block one and the support block two are all made of stainless steel plates into rectangular structures.

3. The stiffness-adjustable three-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that, An air inlet pipe A is installed on one side of the gas chamber A, and a pneumatic valve A is installed on the air inlet pipe A.

4. The stiffness-adjustable three-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that, An air inlet pipe B is installed on one side of the air spring B, and a pneumatic valve B is installed on the air inlet pipe B.

5. The stiffness-adjustable three-degree-of-freedom ultra-low frequency quasi-zero stiffness vibration isolation platform according to claim 1, characterized in that, The controller is connected with the vertical voice coil motor, the horizontal voice coil motor, the acceleration sensor and the position sensor through a cable.

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