Ultra-low-frequency six-degree-of-freedom active vibration isolator based on air floatation

Abstract

An ultra-low-frequency six-degree-of-freedom active vibration isolator based on air floatation comprises a panel, four vibration isolators, a base and a controller, the four vibration isolators are located at the four corners of the top of the base respectively, the tops of the vibration isolators are connected with the top corners of the bottom of the panel, each vibration isolator comprises a top plate and a main air chamber, and the bottom of each main air chamber is connected with a bottom air chamber through an air hole; four side air chambers are installed on the periphery of the main air chamber, a piston A is installed in the main air chamber, the top of the piston A is connected with the top of the main air chamber through a diaphragm, a supporting rod A is installed in the piston A, a spherical rotor is installed at the top of the supporting rod A, and the spherical rotor is in contact connection with the middle of the bottom of the top plate. The bottom of the supporting rod A is connected with the bottom side in the piston A through a ball. The vibration isolation belt of the system is wide, six-degree-of-freedom vibration control of 0.1 Hz to 300 Hz can be achieved, the bearing capacity is large, and the bearing requirement of a 10000kg precise instrument can be met.

Description

Technical Field

[0001] The invention relates to the technical field of vibration isolation devices, in particular to an air-floating ultra-low frequency six-degree-of-freedom active vibration isolator. Background Art

[0002] At present, the semiconductor industry is developing rapidly. The precision requirements of semiconductor production equipment are getting higher and higher, and the equipment is becoming more and more sensitive to environmental requirements such as micro-vibration. A small amount of micro-vibration will reduce the output yield of the equipment or even make the equipment unable to work normally. Therefore, the isolation of micro-vibration is becoming more and more important.

[0003] The vibration isolator can be directly regarded as a low-pass filter, which can effectively filter out environmental vibration interference above its natural frequency, but the suppression effect on vibration interference near its natural frequency is weak, and sometimes even amplifies the vibration amplitude due to resonance. Therefore, in order to obtain better vibration isolation effect in the low frequency band, the method of reducing its natural frequency is usually adopted to avoid resonance at certain frequencies.

[0004] According to vibration reduction theory, the passive vibration isolation system will reduce vibration when the external interference frequency is greater than 1.414 times the natural frequency of the vibration isolation system. It can effectively isolate medium and high frequency vibrations, but its ability to isolate low frequency vibrations, especially ultra-low frequency vibrations, is poor. In order to improve the system's ability to isolate low frequency vibrations, it is necessary to reduce the natural frequency of the system. There are usually two ways to do this: one is to reduce the stiffness of the vibration isolation system; the other is to increase the load-bearing mass. However, for most applications, the mass of the load cannot be increased, so how to reduce the stiffness of the system has become a research hotspot. In addition, general vibration isolators are mainly used to reduce vibration of vertical vibration sources, and pay less attention to vibration reduction control of horizontal vibration sources. Summary of the invention

[0005] The purpose of the present invention is to provide an air-floating ultra-low frequency six-degree-of-freedom active vibration isolator to solve the problems existing in the above-mentioned background technology.

[0006] The technical solution of the present invention is achieved as follows: an air-floating ultra-low frequency six-degree-of-freedom active vibration isolator, comprising a panel, a vibration isolator, a base and a controller, wherein the vibration isolators are four and are respectively located at the four corners of the top of the base, and the top of the vibration isolator is connected to the top corner of the bottom of the panel, the vibration isolator comprises a top plate and a main air chamber, the bottom of the main air chamber is connected to the bottom air chamber through an air hole, four side air chambers are installed around the main air chamber, a piston A is installed inside the main air chamber, the top of the piston A is connected to the top of the main air chamber through a diaphragm, a support rod A is installed inside the piston A, a spherical rotor is installed on the top of the support rod A, the spherical rotor is in contact with the middle of the bottom of the top plate, the bottom of the support rod A is connected to the bottom side of the piston A through a ball, and the outer side of the support rod A is connected to the inner side of the piston A A flexible ring is also installed, a piston B is installed inside the side air chamber, a support rod B is vertically installed on the top of the piston B, the bottom of the support rod B is connected to the bottom side of the bottom of the piston B through a curved surface rotating device, the top of the support rod B is vertically connected to the bottom of the top plate, a vertical voice coil motor is respectively installed between the middle of the outer side of the top of the side air chamber and the top plate, a horizontal voice coil motor is respectively installed between the middle of the inner side of the top of the side air chamber and the support rod B, an acceleration sensor and a position sensor are also installed at the bottom of the top plate, an intake pipe A is opened on one side of the bottom air chamber, a servo valve A is installed on the intake pipe A, an intake pipe B is opened on the outer side of the side air chamber, a servo valve B is installed on the intake pipe B, an opening is provided on the top of the side air chamber, and a lower limit rod and an upper limit rod are installed on the support rod B.

[0007] Furthermore, the lower limit rod is located inside the side air chamber, and the size of the lower limit rod is larger than the diameter of the opening, so the lower limit rod cannot pass through the opening.

[0008] Furthermore, the upper limit rod is located above the side air chamber, the size of the upper limit rod is larger than the diameter of the opening, and the lower limit rod cannot pass through the opening.

[0009] Furthermore, the curved surface rotating device is provided with limit rings around it.

[0010] Furthermore, the panel and the base have the same size and are both made of stainless steel plates in a rectangular structure.

[0011] Furthermore, the controller is located on the top of the base, and the controller is connected to the vertical voice coil motor, the horizontal voice coil motor, the acceleration sensor and the position sensor through cables.

[0012] The beneficial effects of the present invention are: The main air chamber of the present invention is connected in series with the bottom air chamber, which expands the volume of the air chamber and reduces the natural frequency of the system. At the same time, the piston A cooperates with the diaphragm and the ball to play the function of a universal piston. A spherical rotor is installed on the top of the support rod A to cooperate with the universal piston A to reduce the airbag characteristics of the main air chamber, reduce the rigidity of the system, and further reduce the natural frequency of the system. At the same time, a curved surface rotating device is installed at the bottom of the side air chamber support rod B to further reduce the rigidity of the system, thereby further reducing the natural frequency of the system.

[0013] When the present invention uses a vertical high-frequency vibration source, the first high-frequency vibration reduction is achieved through the main air chamber and the bottom air chamber connected in series, and then the second high-frequency vibration reduction is achieved through the four side air chambers connected in parallel; when the present invention uses a horizontal high-frequency vibration source, the first high-frequency vibration reduction is achieved through the combination of a spherical rotor and a universal piston A, and then the second high-frequency vibration reduction is achieved through the restoring force of the curved surface torque of the parallel curved surface rotating device, and vibration reduction control can be achieved for a higher frequency horizontal vibration source; the vibration isolation band of the system of the present invention is relatively wide, and six-degree-of-freedom vibration control of 0.1Hz~300Hz can be achieved, and the bearing capacity is large, which can meet the load-bearing requirements of 10,000kg precision instruments, and the positioning accuracy is high, and the ability to adjust the bearing capacity and stiffness can be adapted to precision instruments of different models, with a wide range of applications and strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention.

[0015] Figure 2 It is a schematic structural diagram of the vibration isolator of the present invention.

[0016] In the figure, 1- panel, 2- vibration isolator, 201- top plate, 202- main air chamber, 203- bottom air chamber, 204- side air chamber, 205- piston A, 206- support rod A, 207- spherical rotor, 208- diaphragm, 209- ball, 210- flexible ring, 211- piston B, 212- support rod B, 213- curved surface rotating device, 214- vertical voice coil motor, 215- horizontal voice coil motor, 216- air hole, 217- acceleration sensor, 218- position sensor, 219- air inlet pipe A, 220- servo valve A, 221- air inlet pipe B, 222- servo valve B, 223- opening, 224- lower limit rod, 225- upper limit rod, 226- limit ring, 227- support plate, 3- base, 4- controller. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be described clearly and completely in conjunction with the embodiments below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] like Figure 1-2 As shown, an air-floating ultra-low frequency six-degree-of-freedom active vibration isolator comprises a panel 1, a vibration isolator 2, a base 3 and a controller 4. The vibration isolator 2 is composed of four components located at the four corners of the top of the base 3, and the top of the vibration isolator 2 is connected to the top corner of the bottom of the panel 1. The vibration isolator 2 comprises a top plate 201 and a main air chamber 202. The bottom of the main air chamber 202 is connected to a bottom air chamber 203 through an air hole 216. Four side air chambers 204 are installed around the main air chamber 202. A piston is installed inside the main air chamber 202. A205, the top of the piston A205 is connected to the top of the main air chamber 202 through a diaphragm 208, a support rod A206 is installed inside the piston A205, a spherical rotor 207 is installed on the top of the support rod A206, the spherical rotor 207 is in contact with the middle of the bottom of the top plate 201, the bottom of the support rod A206 is connected to the bottom side of the piston A205 through a ball 209, and a flexible ring 210 is installed between the outer side of the support rod A206 and the inner side of the piston A205. A piston B211 is installed inside the chamber 204, a support rod B212 is vertically installed on the top of the piston B211, the bottom of the support rod B212 is connected to the bottom side of the bottom of the piston B211 through a curved surface rotating device 213, the top of the support rod B212 is vertically connected to the bottom of the top plate 201, a vertical voice coil motor 214 is installed between the middle of the top outer side of the side air chamber 204 and the top plate 201, and a horizontal voice coil motor 214 is installed between the middle of the top inner side of the side air chamber 204 and the support rod B212. A voice coil motor 215, an acceleration sensor 217 and a position sensor 218 are also installed at the bottom of the top plate 201, an air intake pipe A219 is opened on one side of the bottom air chamber 203, a servo valve A220 is installed on the air intake pipe A219, an air intake pipe B221 is opened on the outside of the side air chamber 204, a servo valve B222 is installed on the air intake pipe B221, an opening 223 is provided on the top of the side air chamber 201, and a lower limit rod 224 and an upper limit rod 225 are installed on the support rod B212.

[0019] The lower limiting rod 224 is located inside the side air chamber 204 . The size of the lower limiting rod 224 is larger than the diameter of the opening 223 , and the lower limiting rod 224 cannot pass through the opening 223 .

[0020] The upper limit rod 225 is located above the side air chamber 204 . The size of the upper limit rod 225 is larger than the diameter of the opening 223 . The lower limit rod 225 cannot pass through the opening 223 .

[0021] The curved surface rotating device 213 is provided with limiting rings 226 around its periphery.

[0022] The panel 1 and the base 3 have the same size and are both made of stainless steel plates in a rectangular structure.

[0023] The controller 4 is located on the top of the base 3 , and is connected to the vertical voice coil motor 214 , the horizontal voice coil motor 215 , the acceleration sensor 217 and the position sensor 218 through cables.

[0024] During installation, the load is mounted on panel 1, and then the air pressure of the main air chamber 202 and the side air chamber 204 is controlled by adjusting the servo valve 220 and the servo valve 222 according to the weight of the load to ensure that the load-bearing requirements are met. When the system reaches static balance, the lower limit rod 224 and the upper limit rod 225 are in a non-contact state with the side air chamber 204.

[0025] During operation, vibration signals are collected through the acceleration sensor 217 and the position sensor 218, and then the signals are transmitted to the controller 4. When the vibration source is vertical, the first high-frequency vibration reduction is first achieved through the main air chamber 202 and the bottom air chamber 203 connected in series, and then the second high-frequency vibration reduction is achieved through the four side air chambers 204 connected in parallel; when the vibration source is horizontal, the first high-frequency vibration reduction is achieved through the combination of the spherical rotor 207 and the universal piston A, and then the second high-frequency vibration reduction is achieved through the restoring force of the curved surface moment of the parallel curved surface rotating device 213; when the vibration source is vertical, the vibration reduction is achieved through the vertical voice coil motor 214; when the vibration source is horizontal, the vibration reduction is achieved through the horizontal voice coil motor 215.

[0026] The present invention can realize six-degree-of-freedom vibration reduction of X-axis, Y-axis, Z-axis, around X-axis, around Y-axis and around Z-axis.

[0027] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An air-floating ultra-low frequency six-degree-of-freedom active vibration isolator, comprising a panel, a vibration isolator, a base and a controller, characterized in that: The vibration isolator is composed of four parts, which are respectively located at the four corners of the top of the base. The top of the vibration isolator is connected to the top corner of the bottom of the panel. The vibration isolator includes a top plate and a main air chamber. The bottom of the main air chamber is connected to the bottom air chamber through an air hole. Four side air chambers are installed around the main air chamber. A piston A is installed inside the main air chamber. The top of the piston A is connected to the top of the main air chamber through a diaphragm. A support rod A is installed inside the piston A. A spherical rotor is installed on the top of the support rod A. The spherical rotor is in contact with the middle of the bottom of the top plate. The bottom of the support rod A is connected to the bottom side of the piston A through a ball. A flexible ring is also installed between the outer side of the support rod A and the inner side of the piston A. A piston B is installed inside the side air chamber. A support rod B is vertically installed on the top of plug B, and the bottom of the support rod B is connected to the inner bottom side of the bottom of the piston B through a curved surface rotating device, and the top of the support rod B is vertically connected to the bottom of the top plate. Vertical voice coil motors are respectively installed between the outer middle of the top of the side air chamber and the top plate, and horizontal voice coil motors are respectively installed between the inner middle of the top of the side air chamber and the support rod B. An acceleration sensor and a position sensor are also installed at the bottom of the top plate. An intake pipe A is opened on one side of the bottom air chamber, and a servo valve A is installed on the intake pipe A. An intake pipe B is opened on the outer side of the side air chamber, and a servo valve B is installed on the intake pipe B. An opening is provided on the top of the side air chamber, and a lower limit rod and an upper limit rod are installed on the support rod B.

2. The air-floating ultra-low frequency six-degree-of-freedom active vibration isolator according to claim 1, characterized in that: The lower limit rod is located inside the side air chamber, and the size of the lower limit rod is larger than the diameter of the opening, so the lower limit rod cannot pass through the opening.

3. The air-floating ultra-low frequency six-degree-of-freedom active vibration isolator according to claim 1, characterized in that: The upper limit rod is located above the side air chamber, the size of the upper limit rod is larger than the diameter of the opening, and the lower limit rod cannot pass through the opening.

4. The air-floating ultra-low frequency six-degree-of-freedom active vibration isolator according to claim 1, characterized in that: Limiting rings are installed around the curved surface rotating device.

5. The air-floating ultra-low frequency six-degree-of-freedom active vibration isolator according to claim 1, characterized in that: The panel and the base are of the same size and are both made of stainless steel plates in a rectangular structure.

6. The air-floating ultra-low frequency six-degree-of-freedom active vibration isolator according to claim 1, characterized in that: The controller is located on the top of the base, and is connected with the vertical voice coil motor, the horizontal voice coil motor, the acceleration sensor and the position sensor through cables.

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