A three-degree-of-freedom quasi-zero-stiffness vibration isolator

Abstract

The present invention provides a three-degree-of-freedom quasi-zero stiffness vibration isolator, including a table, a base, a baffle and a vertical vibration isolator, the baffles are vertically welded around the top of the base, the middle of the bottom of the table is vertically connected to the vertical vibration isolator, and the middle of the sides of the table and the baffle are respectively vertically connected with horizontal vibration isolators. The present invention can achieve quasi-zero stiffness in the three degrees of freedom in the vertical and horizontal directions, the system vibration isolation band is wide, and vibration control of 0.1Hz~300Hz can be achieved, and the system has large static stiffness and large bearing capacity, which can meet the load-bearing requirements of 10,000kg precision instruments, and has high positioning accuracy, and has the ability to adjust bearing capacity and stiffness, and can be adapted to precision instruments of different models, with a wide range of applications and strong versatility.

Description

Technical Field

[0001] The invention relates to the technical field of vibration isolation devices, in particular to a three-degree-of-freedom quasi-zero-rigidity 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] Quasi-zero stiffness isolator is a combination isolator that connects positive and negative stiffness elastic components in parallel at a static equilibrium position to obtain zero stiffness. This type of isolator has a large static stiffness and can bear the weight of the isolated equipment. When the equipment vibrates at a static equilibrium position, the stiffness is very low, or even approaches zero, which is conducive to low-frequency vibration isolation. Most quasi-zero stiffness isolators are designed for a single vibration isolation object. Once the isolator is manufactured, the structural parameters cannot be changed. Therefore, when the vibration isolation mass changes, such as overload or underload, the isolator no longer has the quasi-zero stiffness characteristic, the vibration isolation performance decreases, and the effect is even worse than that of the linear vibration isolation system, which greatly limits its application range. A small number of isolators can still have quasi-zero stiffness characteristics under variable loads, but the vibration isolation mass cannot change continuously. The isolator can only maintain quasi-zero stiffness at several specific masses, with a small scope of application, and generally cannot meet the vibration isolation requirements of large loads. In addition, at present, most quasi-zero stiffness isolators can achieve quasi-zero stiffness for a single vertical degree of freedom, and cannot achieve quasi-zero stiffness for multiple degrees of freedom. Summary of the invention

[0004] The object of the present invention is to provide a three-degree-of-freedom quasi-zero stiffness vibration isolator to solve the problems existing in the above-mentioned background technology.

[0005] The technical solution of the present invention is achieved as follows: a three-degree-of-freedom quasi-zero stiffness vibration isolator comprises a table, a base, a baffle and a vertical vibration isolator, baffles are vertically welded around the top of the base, the middle of the bottom of the table is vertically connected to the vertical vibration isolator, horizontal vibration isolators are vertically connected between the middle of the sides of the table and the baffle, the vertical vibration isolator comprises a support rod A and a support plate A, the top of the support rod A is vertically connected to the middle of the bottom of the table, the bottom of the support rod A is vertically welded to the middle of the top of the support plate A, an air spring is installed between the middle of the bottom of the support plate A and the base, bottom plates A are respectively installed on both sides of the air spring and the top of the base, side plates A are vertically welded to the outer side of the top of the bottom plate A, the top of the side plate A is vertically welded to the outer side of the bottom of the top plate A, permanent magnets A are respectively installed on both sides of the bottom of the support plate A, electromagnets A are installed at the top of the bottom plate A at a position vertically corresponding to the permanent magnet A, electromagnets B are respectively installed on both sides of the top of the support plate A, and the top plate A permanent magnet B is installed at a position vertically corresponding to the electromagnet B at the bottom of A, a vertical voice coil motor is installed between the top of the top plate A and the bottom of the table, the horizontal vibration isolator includes a support rod B and a support plate B, the top of the support rod B is vertically connected to the middle of the side of the table, the bottom of the support rod B is vertically welded to the middle of the top of the support plate B, permanent magnets C are installed on both sides of the bottom of the support plate B, an electromagnet C is installed on the inner side of the baffle at a position vertically corresponding to the permanent magnet C, a bottom plate B is also installed between the electromagnet C and the baffle, a side plate B is vertically welded on the outer side of the bottom of the bottom plate B, the top of the side plate B is vertically welded to the outer side of the bottom of the top plate B, metal springs are respectively installed between the two sides of the top of the support plate B and the bottom of the top plate B, horizontal voice coil motors are respectively installed between the top of the top plate B and the side of the table, an acceleration sensor and a position sensor are also installed at the bottom of the table, a controller is also installed on the top of the base, and ball joints are also installed between the support rods A, support rods B and the table.

[0006] Furthermore, there is an attractive force between the permanent magnet A and the electromagnet A, between the permanent magnet B and the electromagnet B, and between the permanent magnet C and the electromagnet C.

[0007] Furthermore, the table top is made of a stainless steel plate in a square structure.

[0008] Furthermore, the bottom plate A, side plate A, top plate A, bottom plate B, bottom plate B, and top plate B are all magnetic isolation plates.

[0009] Furthermore, the support plate A and the support plate B are also magnetic isolation plates.

[0010] Furthermore, an air intake pipe is provided on one side of the bottom plate A and is connected to the air spring, and a servo valve is installed on the air intake pipe.

[0011] Furthermore, the controller is connected to the electromagnet A, the electromagnet B, the electromagnet C, the vertical voice coil motor, the horizontal voice coil motor, the acceleration sensor and the position sensor through cables.

[0012] Furthermore, the ball joint is a flexible ball joint.

[0013] The beneficial effects of the present invention are: The present invention realizes negative stiffness adjustment vertically through four groups of magnetic levitation devices, and provides positive stiffness through air springs. Negative stiffness adjustment horizontally through sixteen groups of magnetic levitation devices, and provides positive stiffness through eight groups of metal springs. The system can achieve quasi-zero stiffness in three degrees of freedom in the vertical and horizontal directions.

[0014] When the present invention is a vertical high-frequency vibration source, firstly, the air spring is passed to realize the first vertical high-frequency vibration reduction. Secondly, the current of electromagnet B is increased by the controller to enhance the attraction between electromagnet B and permanent magnet B. At the same time, the controller 8 controls to reduce the current of electromagnet A to weaken the attraction between electromagnet A and permanent magnet A, thereby realizing the second and third vertical high-frequency vibration reduction. When the present invention is a horizontal high-frequency vibration source, one of the metal springs on both sides of the table is compressed and the other is stretched to realize the first and second horizontal high-frequency vibration reduction. Secondly, the controller controls to increase the current opposite to the movement of the table. The controller reduces the current of the electromagnet C on the same side as the table movement, thereby weakening the attraction between the electromagnet C and the permanent magnet C, thereby achieving the third and fourth high-frequency vibration reduction in the horizontal direction; when the low-frequency vibration source is vertical, the vertical voice coil motor is controlled by the controller to achieve vertical low-frequency vibration reduction; when the low-frequency vibration source is horizontal, the horizontal voice coil motor is controlled by the controller to achieve low-frequency vibration reduction; the horizontal low-frequency vibration source is realized by the voice coil motor to achieve vibration reduction, so that the system can achieve vibration reduction for lower vibration frequencies.

[0015] The present invention can achieve quasi-zero stiffness in three degrees of freedom in the vertical and horizontal directions. The system has a wide vibration isolation band and can achieve vibration control of 0.1Hz~300Hz. The system has large static stiffness and bearing capacity, which can meet the load-bearing requirements of 10,000kg precision instruments. It also has high positioning accuracy and the ability to adjust bearing capacity and stiffness. It can be adapted to precision instruments of different models, has a wide range of applications, and is highly versatile. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] Figure 2 It is the front view of the present invention.

[0018] In the figure, 1-table, 2-base, 3-baffle, 4-vertical vibration isolator, 401-support rod A, 402-support plate A, 403-air spring, 404-bottom plate A, 405-side plate A, 406-top plate A, 407-permanent magnet A, 408-electromagnet A, 409-permanent magnet B, 410-electromagnet B, 411-vertical voice coil motor, 412-intake pipe, 413-servo valve, 5-horizontal vibration isolator, 501-support rod B, 502-support plate B, 503-bottom plate B, 504-side plate B, 505-top plate B, 506-permanent magnet C, 507-electromagnet C, 508-metal spring, 509-horizontal voice coil motor, 6 deceleration sensor, 7-position sensor, 8-controller, 9-ball joint. DETAILED DESCRIPTION

[0019] 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.

[0020] like Figure 1-2As shown, a three-degree-of-freedom quasi-zero stiffness vibration isolator comprises a table 1, a base 2, a baffle 3 and a vertical vibration isolator 4, wherein the baffle 3 is vertically welded around the top of the base 1, the middle of the bottom of the table 1 is vertically connected to the vertical vibration isolator 4, and horizontal vibration isolators 5 are vertically connected between the middle of the sides of the table 1 and the baffle 3, respectively, and the vertical vibration isolator 4 comprises a support rod A401 and a support plate A402, the top of the support rod A401 is vertically connected to the middle of the bottom of the table 1, the bottom of the support rod A401 is vertically welded to the middle of the top of the support plate A402, and the middle of the bottom of the support plate A402 is vertically connected to the base 2. An air spring 403 is installed between the support plate A402 and the support plate 1. Bottom plates A404 are installed on both sides of the air spring 403 and on the top of the base 1. Side plates A405 are vertically welded to the outer side of the top of the bottom plate A404. The top of the side plate A405 is vertically welded to the outer side of the bottom of the top plate A406. Permanent magnets A407 are installed on both sides of the bottom of the support plate A402. Electromagnets A408 are installed at the top of the bottom plate A404 at a position corresponding to the permanent magnet A407. Electromagnets B410 are installed on both sides of the top of the support plate A402. The bottom of the top plate A406 is vertically welded to the electromagnet B410. A permanent magnet B409 is installed at the corresponding position, a vertical voice coil motor 411 is installed between the top of the top plate A406 and the bottom of the table 1, and the horizontal vibration isolator 5 includes a support rod B501 and a support plate B502. The top of the support rod B501 is vertically connected to the middle of the side of the table 1, and the bottom of the support rod B501 is vertically welded to the middle of the top of the support plate B502. Permanent magnets C506 are installed on both sides of the bottom of the support plate B502. An electromagnet C507 is installed on the inner side of the baffle 3 at a position vertically corresponding to the permanent magnet C506. There is also a The bottom plate B503 has a side plate B504 vertically welded to the outer side of the bottom plate B503, the top of the side plate B504 is vertically welded to the outer side of the bottom of the top plate B505, metal springs 508 are respectively installed between the two sides of the top of the support plate B502 and the bottom of the top plate B505, horizontal voice coil motors 509 are respectively installed between the top of the top plate B505 and the side of the table top 1, an acceleration sensor 6 and a position sensor 7 are also installed at the bottom of the table top 1, a controller 7 is also installed at the top of the base 2, and ball joints 9 are also installed between the support rods A404, B501 and the table top 1.

[0021] There is attraction between the permanent magnet A407 and the electromagnet A408, between the permanent magnet B409 and the electromagnet B410, and between the permanent magnet C506 and the electromagnet C507.

[0022] The table top 1 is made of a stainless steel plate and has a square structure.

[0023] The bottom plate A404, side plate A405, top plate A406, bottom plate B503, bottom plate B504 and top plate B505 are all magnetic isolation plates.

[0024] The support plate A402 and the support plate B502 are also magnetic isolation plates.

[0025] An air inlet pipe 412 is provided on one side of the bottom plate A404 and is in communication with the air spring 403 . A servo valve 413 is installed on the air inlet pipe 412 .

[0026] The controller 8 is connected to the electromagnet / 408, the electromagnet B400, the electromagnet C507, the vertical voice coil motor 411, the horizontal voice coil motor 509, the acceleration sensor 6 and the position sensor 7 through cables.

[0027] The ball joint 9 is a flexible ball joint.

[0028] During installation, the air pressure of the air spring 403 is controlled by adjusting the servo valve 413 according to the weight of the precision instrument to ensure that the load-bearing requirements are met and positive stiffness is provided for the system vertically. Then the precision instrument is placed on the table 1; the current of the electromagnet A408 and the electromagnet B410 is controlled by the controller 8, thereby controlling the strength of the electromagnetic field generated by them, and then controlling the attraction between the electromagnet A408 and the permanent magnet A407, and the attraction between the electromagnet B410 and the permanent magnet B409, respectively, thereby controlling the vertical negative stiffness of the system. The size of the positive and negative stiffness in parallel with the air spring 403 can be adjusted by controlling the air pressure of the air spring 403. In the horizontal direction of the system, the current of the electromagnet C507 is controlled by the controller 8, thereby controlling the strength of the electromagnetic field generated by it, and then controlling the attraction between the electromagnet C507 and the permanent magnet C508. The attraction between the electromagnet C507 and the permanent magnet C508 is the same, thereby controlling the negative stiffness in the horizontal direction of the system. At this time, the metal spring 508 is in a natural expansion and contraction state. Through the adjustment of positive and negative stiffness, the system reaches static quasi-zero stiffness in the three degrees of freedom in the vertical and horizontal directions when it is in the initial equilibrium position.

[0029] During operation, vibration signals are collected through the acceleration sensor 6 and the position sensor 7, and then the signals are transmitted to the controller 8. When the vibration source is vertical, the air spring 403 is firstly passed to realize the first vertical high-frequency vibration reduction. Secondly, the current of the electromagnet B410 is increased through the controller 8 to enhance the attraction between the electromagnet B410 and the permanent magnet B409. At the same time, the controller 8 controls to reduce the current of the electromagnet A408 to weaken the attraction between the electromagnet A408 and the permanent magnet A407, thereby realizing the second and third vertical high-frequency vibration reduction. When the vibration source is horizontal, the metal springs 508 on both sides of the table 1 are compressed and stretched to realize the first and second horizontal high-frequency vibration reduction. Secondly, through The controller 8 controls to increase the current of the electromagnet C507 on the side opposite to the movement of the table 1, thereby enhancing the attraction between the electromagnet C507 and the permanent magnet C506. At the same time, the controller 8 reduces the current of the electromagnet C507 on the same side as the movement of the table 1, thereby weakening the attraction between the electromagnet C507 and the permanent magnet C506, thereby achieving the third and fourth high-frequency vibration reduction in the horizontal direction; when the low-frequency vibration source is vertical, the vertical voice coil motor 411 is controlled by the controller 8 to achieve vertical low-frequency vibration reduction; when the low-frequency vibration source is horizontal, the horizontal voice coil motor 509 is controlled by the controller 8 to achieve low-frequency vibration reduction.

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

Claims

1. A three-degree-of-freedom quasi-zero stiffness vibration isolator, comprising a table, a base, a baffle and a vertical vibration isolator, characterized in that: Baffles are vertically welded around the top of the base, the middle of the bottom of the table top is vertically connected to the vertical vibration isolator, and horizontal vibration isolators are vertically connected between the middle of the sides of the table top and the baffles. The vertical vibration isolator includes a support rod A and a support plate A. The top of the support rod A is vertically connected to the middle of the bottom of the table top, and the bottom of the support rod A is vertically welded to the middle of the top of the support plate A. An air spring is installed between the middle of the bottom of the support plate A and the base. Bottom plates A are installed on both sides of the air spring and the top of the base respectively. Side plates A are vertically welded on the outer side of the top of the bottom plate A. The top of the side plate A is vertically welded to the outer side of the bottom of the top plate A. Permanent magnets A are installed on both sides of the bottom of the support plate A, and electromagnets A are installed at the top of the bottom plate A at positions corresponding to the permanent magnet A. Electromagnets B are installed on both sides of the top of the support plate A, and permanent magnets B are installed at the bottom of the top plate A at positions corresponding to the electromagnet B. A vertical voice coil motor is respectively installed between the top of the top plate A and the bottom of the table top. The horizontal vibration isolator includes a support rod B and a support plate B. The top of the support rod B is vertically connected to the middle of the side surface of the table top. The bottom of the support rod B is vertically welded to the middle of the top of the support plate B. Permanent magnets C are respectively installed on both sides of the bottom of the support plate B. An electromagnet C is installed on the inner side of the baffle at a position vertically corresponding to the permanent magnet C. A bottom plate B is also installed between the electromagnet C and the baffle. A side plate B is vertically welded to the outer side of the bottom of the bottom plate B. The top of the side plate B is vertically welded to the outer side of the bottom of the top plate B. Metal springs are respectively installed between the two sides of the top of the support plate B and the bottom of the top plate B. Horizontal voice coil motors are respectively installed between the top of the top plate B and the side surface of the table top. An acceleration sensor and a position sensor are also installed at the bottom of the table top. A controller is also installed on the top of the base. Ball joints are also installed between the support rods A, B and the table top.

2. A three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: There is attraction between the permanent magnet A and the electromagnet A, between the permanent magnet B and the electromagnet B, and between the permanent magnet C and the electromagnet C.

3. The three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The table top is made of a stainless steel plate and has a square structure.

4. The three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The bottom plate A, side plate A, top plate A, bottom plate B, bottom plate B and top plate B are all magnetic isolation plates.

5. The three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The support plate A and the support plate B are also magnetic isolation plates.

6. The three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: An air intake pipe is provided on one side of the bottom plate A and is connected to the air spring. A servo valve is installed on the air intake pipe.

7. The three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The controller is connected with the electromagnet A, the electromagnet B, the electromagnet C, the vertical voice coil motor, the horizontal voice coil motor, the acceleration sensor and the position sensor through cables.

8. The three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The ball joint is a flexible ball joint.

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