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

Abstract

The present invention provides a variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator, comprising a top plate, an outer shell, an air spring and an additional air chamber, wherein an air spring is connected to the middle of the top of the additional air chamber, a swing rod is installed on the top of the air spring, the top of the swing rod is vertically connected to the middle of the bottom of the top plate, a support plate A is installed between the additional air chamber and the air spring, an iron pipe A is sleeved on the top of the support plate A and the periphery of the air spring, a coil A is wound around the outside of the iron pipe A, a permanent magnet A is installed above the iron pipe A and the lower part of the swing rod, a support plate A is installed on the top of the permanent magnet A and the swing rod, a support plate B is installed above the support plate A and the inner side of the outer shell, an iron pipe B is sleeved on the top of the support plate B and the periphery of the swing rod, a coil B is wound around the outside of the iron pipe B, and a permanent magnet B is installed above the iron pipe B and on the swing rod. The present invention has the ability to adjust the bearing capacity and stiffness, a wide vibration isolation band, a wide range of application, and strong versatility.

Description

Technical Field

[0001] The invention relates to the technical field of vibration isolation devices, in particular to a variable-rigidity 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. The equipment is also more and more sensitive to the environment 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. Quasi-zero stiffness isolator is a combined 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, even approaching zero, which is conducive to low-frequency vibration isolation. Most quasi-zero stiffness isolators are designed only for a single vibration isolation object. Once the vibration isolator is manufactured, the structural parameters cannot be changed. Therefore, when the vibration isolation quality changes, such as overload or underload, the vibration isolator no longer has the quasi-zero stiffness characteristics, the vibration isolation performance decreases, and the effect is even worse than that of the linear vibration isolation system, which greatly limits its scope of application. A small number of vibration isolators can achieve quasi-zero stiffness characteristics under variable loads, but the isolation mass cannot change continuously. The vibration isolators can only maintain quasi-zero stiffness at several specific masses, have a small scope of application, and generally cannot meet the vibration isolation requirements of large loads. Summary of the invention

[0003] The object of the present invention is to provide a variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator to solve the problems existing in the above-mentioned background technology.

[0004] The technical solution of the present invention is achieved as follows: a variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator comprises a top plate, an outer shell, an air spring and an additional air chamber, wherein the additional air chamber is located at the inner bottom of the outer shell, an air spring is connected to the middle of the top of the additional air chamber, a swing rod is installed on the top of the air spring, the top of the swing rod is vertically connected to the middle of the bottom of the top plate, a support plate A is installed between the additional air chamber and the air spring, air holes are opened on the support plate A, an iron pipe A is sleeved on the top of the support plate A and the periphery of the air spring, a coil A is wound around the outside of the iron pipe A, a permanent magnet A is installed above the iron pipe A and at the bottom of the swing rod, a support plate A is installed on the top of the permanent magnet A and on the swing rod, a magnetic isolation plate A is installed between the support plate A and the permanent magnet A, a support plate B is installed above the support plate A and on the inner side of the outer shell, an iron pipe B is sleeved on the top of the support plate B and the periphery of the swing rod, a coil B is wound around the outside of the iron pipe B, and a permanent magnet is installed above the iron pipe B and on the swing rod B, a support plate B is installed on the top of the permanent magnet B and on the swing arm, a magnetic isolation plate B is installed between the support plate B and the permanent magnet B, vertical springs are respectively installed between the inner side of the top of the shell and the support plate B, and on the left and right sides of the swing arm, vertical voice coil motors are respectively installed between the top of the shell and the top plate, and on the left and right sides of the swing arm, transverse springs A are respectively installed between the left and rear sides of the support plate A and the shell, transverse springs B are respectively installed between the right and front sides of the support plate B and the shell, transverse voice coil motors A are respectively installed between the right and front sides of the support plate A and the shell, transverse voice coil motors B are respectively installed between the left and rear sides of the support plate B and the shell, a vertical acceleration sensor and a vertical position sensor are respectively installed at the bottom of the top plate, a transverse acceleration sensor A and a transverse position sensor A are respectively installed at the top of the support plate A, a transverse acceleration sensor B and a transverse position sensor B are respectively installed at the top of the support plate B, and a controller is also installed at the top of the shell.

[0005] Furthermore, the permanent magnet A and the permanent magnet B have the same magnetic pole direction, and the current directions of the coil A and the coil B are opposite. After power is turned on, the magnetic field generated by the permanent magnet A and the coil A exhibits an attractive force, and the magnetic field generated by the permanent magnet B and the coil B exhibits a repulsive force.

[0006] Furthermore, the shell is of a rectangular structure and has magnetic isolation performance. An opening is provided on the top of the shell, and a certain gap is maintained between the rocker arm and the shell when the rocker arm passes through the opening.

[0007] Furthermore, the rocker arm is a flexible rocker arm.

[0008] Furthermore, the vertical spring, transverse spring A, and transverse spring B are all metal springs.

[0009] Furthermore, the air hole is used to connect the air spring with the additional air chamber and has a certain damping effect.

[0010] Furthermore, a frame A and a frame B are installed on the inner side of the shell for installing coil A and coil B respectively.

[0011] Furthermore, an air inlet pipe is provided at the bottom of the side of the shell and is connected to the additional air chamber, and a servo valve is installed on the air inlet pipe.

[0012] Furthermore, the controller is connected to coil A, coil B, vertical voice coil motor, lateral voice coil motor A, lateral voice coil motor B, vertical acceleration sensor, vertical position sensor, lateral acceleration sensor A, lateral position sensor A, lateral acceleration sensor B and lateral position sensor B through cables.

[0013] The beneficial effects of the present invention are:

[0014] The present invention realizes load-bearing through air springs, which can meet the load-bearing requirements of large precision instruments. The volume of the air chamber is enlarged by connecting the air spring with the additional air chamber, thereby reducing the vertical natural frequency of the system. Two sets of parallel magnetic levitation devices respectively pass currents in different directions into the coils to generate magnetic forces in opposite directions between the coils and the permanent magnets in the vertical direction. The magnitude of the currents is controlled to control the magnitude of the magnetic force and thus adjust the negative stiffness of the system. At the same time, the pressure of the air spring is controlled by the servo valve to adjust the positive stiffness of the system, so that the system reaches static quasi-zero stiffness at the initial equilibrium position.

[0015] The present invention realizes three-time vibration reduction for the vertical high-frequency vibration source through the air spring and the parallel vertical spring and magnetic levitation device, and realizes two-time vibration reduction for the horizontal high-frequency vibration source through the rocker rod and the horizontal spring in parallel, so that the system can realize vibration reduction for higher vibration frequencies; the vertical low-frequency and horizontal low-frequency vibration sources are respectively realized by parallel voice coil motors, so that the system can realize vibration reduction for lower vibration frequencies. The system has a wide vibration isolation band and can realize vibration control of 0.1Hz~200Hz.

[0016] The system of the present invention has large static rigidity and large bearing capacity, can meet the load-bearing requirements of 5000kg precision instruments, has high positioning accuracy, has the ability to adjust the bearing capacity and rigidity, can be adapted to precision instruments of different models, has a wide range of applications, and has strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] In the figure, 1-top plate, 2-housing, 3-air spring, 4-additional air chamber, 401-intake pipe, 402-servo valve, 5-rocker, 6-support plate A, 7-air hole, 8-iron pipe A, 9-wire A, 10-permanent magnet A, 11-support plate A, 12-magnetic isolation plate A, 13-support plate B, 14-iron pipe B, 15-coil B, 16-permanent magnet B, 17-support plate B, 18-magnetic isolation plate B, 19-vertical spring, 2 0-vertical voice coil motor, 21-lateral spring A, 22-lateral spring B, 23-lateral voice coil motor A, 24-lateral voice coil motor B, 25-vertical acceleration sensor, 26-vertical position sensor, 27-lateral acceleration sensor A, 28-lateral position sensor A, 29-lateral acceleration sensor B, 30-lateral position sensor, 31-controller, 32-skeleton A, 33-skeleton B, 34-opening. 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 1As shown, a variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator comprises a top plate 1, a shell 2, an air spring 3 and an additional air chamber 4, wherein the additional air chamber 4 is located at the inner bottom of the shell 2, the top of the additional air chamber 4 is connected to the air spring 3, a swing rod 5 is installed on the top of the air spring 3, the top of the swing rod 5 is vertically connected to the middle of the bottom of the top plate 1, a support plate A6 is installed between the additional air chamber 4 and the air spring 3, an air hole 7 is opened on the support plate A6, an iron pipe A8 is sleeved on the top of the support plate A6 and the periphery of the air spring 3, and the iron pipe A8 is sleeved on the top of the support plate A6 and the periphery of the air spring 3. A coil A9 is wound around the outer side of A8, a permanent magnet A10 is installed above the iron tube A8 and at the bottom of the pendulum 5, a support plate A11 is installed on the top of the permanent magnet A10 and on the pendulum 5, a magnetic isolation plate A12 is installed between the support plate A11 and the permanent magnet A10, a support plate B13 is installed above the support plate A11 and inside the shell 2, an iron tube B14 is sleeved on the top of the support plate B13 and outside the pendulum 5, a coil B15 is wound around the outer side of the iron tube B15, a permanent magnet B16 is installed above the iron tube B14 and on the pendulum 5, and the permanent magnet B16 is installed on the top of the iron tube B14 and on the pendulum 5. 6, a support plate B17 is installed on the top of the swing rod 5, a magnetic isolation plate B18 is installed between the support plate B17 and the permanent magnet B16, vertical springs 19 are installed between the inner side of the top of the housing 2 and the support plate B17, and on the left and right sides of the swing rod 5, vertical voice coil motors 20 are installed between the top of the housing 2 and the top plate 4, and on the left and right sides of the swing rod 5, transverse springs A21 are installed between the left and rear sides of the support plate A11 and the housing 2, transverse springs B22 are installed between the right and front sides of the support plate B17 and the housing 2, and the right side of the support plate A11 is installed between the top plate 4 and the housing 2. A horizontal voice coil motor A23 is installed between the side and front sides and the outer shell 2, a horizontal voice coil motor B24 is installed between the left side and rear side of the support plate B17 and the outer shell 2, a vertical acceleration sensor 25 and a vertical position sensor 26 are installed at the bottom of the top plate 1, a horizontal acceleration sensor A27 and a horizontal position sensor A28 are installed at the top of the support plate A11, a horizontal acceleration sensor B29 and a horizontal position sensor B30 are installed at the top of the support plate B17, and a controller 31 is installed at the top of the outer shell 2.

[0021] The magnetic poles of the permanent magnet A10 and the permanent magnet B16 are in the same direction, and the currents of the coils A9 and B15 are in opposite directions. After power is turned on, the magnetic fields generated by the permanent magnet A10 and the coil A9 show an attractive force, and the magnetic fields generated by the permanent magnet B16 and the coil B15 show a repulsive force.

[0022] The housing 2 is of a rectangular structure and has magnetic isolation performance. An opening 34 is provided on the top of the housing 2 . The swing rod 5 passes through the opening 34 and a certain gap is maintained between the swing rod 5 and the housing 2 .

[0023] The swing rod is a flexible swing rod.

[0024] The vertical spring 19, the transverse spring A21 and the transverse spring B22 are all metal springs.

[0025] The air hole 7 is used to connect the air spring 3 with the additional air chamber 4 and has a certain damping effect.

[0026] The inner side of the housing 2 is also provided with a frame A32 and a frame B33 for installing the coil A9 and the coil B15 respectively.

[0027] An air inlet pipe 401 is provided at the bottom of the side of the housing 2 and is in communication with the additional air chamber 4 . A servo valve 402 is installed on the air inlet pipe 401 .

[0028] The controller 31 is connected to the coil A9, coil B15, vertical voice coil motor 20, lateral voice coil motor A21, lateral voice coil motor B22, vertical acceleration sensor 25, vertical position sensor 26, lateral acceleration sensor A27, lateral position sensor A28, lateral acceleration sensor B29 and lateral position sensor B30 through cables.

[0029] During installation, first determine the weight of the precision instrument to be loaded, then adjust the servo valve 402 to control the air pressure of the air spring 31 according to the weight of the precision instrument to ensure that the load-bearing requirements are met, then place the precision instrument on the top plate 1, and then control the current of coil A9 and coil B15 respectively through the controller 31, thereby controlling the strength of the electromagnetic field generated by them, and then controlling the size of the attractive force between the permanent magnet A10 and the repulsive force between the permanent magnet B16, thereby adjusting the positive and negative stiffness of the system so that the system reaches a static quasi-zero stiffness at the initial equilibrium position.

[0030] During operation, the vibration signal is collected by the vertical acceleration sensor 25 , the vertical position sensor 26 , the lateral acceleration sensor A27 , the lateral position sensor A28 , the lateral acceleration sensor B29 and the lateral position sensor B30 , and then the signal is transmitted to the controller 31 . When the vibration source is vertical, the first vibration reduction is achieved through the air spring 3, and then the second vibration reduction is achieved through the parallel vertical spring 19. Finally, the current of coil A9 and coil B15 can be controlled by the controller 31, so as to control the strength of the electromagnetic field generated by them, and then the attractive force between permanent magnet A10 and repulsive force between permanent magnet B16 can be controlled respectively, so as to further achieve the third vibration reduction. When the vibration source is vertical, the vertical voice coil motor 20 connected in parallel is controlled by the controller 31 to achieve vibration reduction. When the vibration source is horizontal, the first vibration reduction is achieved through the rocker 5, and then the second vibration reduction is achieved through the horizontal spring A and the horizontal spring B connected in parallel. When the vibration source is horizontal, the horizontal voice coil motor A23 and the horizontal voice coil motor B24 connected in parallel are controlled by the controller 31 to achieve vibration reduction.

[0031] 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 variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator, comprising a top plate, a shell, an air spring and an additional air chamber, characterized in that: The additional air chamber is located at the bottom inner side of the shell, an air spring is connected in the middle of the top of the additional air chamber, a swing rod is installed on the top of the air spring, the top of the swing rod is vertically connected to the middle of the bottom of the top plate, a support plate A is installed between the additional air chamber and the air spring, an air hole is opened on the support plate A, an iron pipe A is sleeved on the top of the support plate A and the periphery of the air spring, a coil A is wound around the outside of the iron pipe A, a permanent magnet A is installed above the iron pipe A and at the bottom of the swing rod, a support plate A is installed on the top of the permanent magnet A and on the swing rod, a magnetic isolation plate A is installed between the support plate A and the permanent magnet A, a support plate B is installed above the support plate A and at the inner side of the shell, an iron pipe B is sleeved on the top of the support plate B and the periphery of the swing rod, a coil B is wound around the outside of the iron pipe B, a permanent magnet B is installed above the iron pipe B and on the swing rod, a support plate B is installed on the top of the permanent magnet B and on the swing rod, a magnetic isolation plate B is installed between the support plate B and the permanent magnet B, the inner side of the shell top and the support plate B, and the swing rod Vertical springs are installed on the left and right sides respectively, vertical voice coil motors are installed between the top of the shell and the top plate and on the left and right sides of the swing arm respectively, transverse springs A are installed between the left and rear sides of the support plate A and the shell respectively, transverse springs B are installed between the right and front sides of the support plate B and the shell respectively, transverse voice coil motors A are installed between the right and front sides of the support plate A and the shell respectively, transverse voice coil motors B are installed between the left and rear sides of the support plate B and the shell respectively, vertical acceleration sensors and vertical position sensors are also installed on the bottom of the top plate respectively, transverse acceleration sensors A and transverse position sensors A are also installed on the top of the support plate A respectively, transverse acceleration sensors B and transverse position sensors B are also installed on the top of the support plate B respectively, a controller is also installed on the top of the shell, the air hole is used to connect the air spring with the additional air chamber, and has a certain damping effect, an air intake pipe connected with the additional air chamber is opened at the bottom of the side of the shell, and a servo valve is installed on the air intake pipe; Determine the weight of the precision instrument to be loaded, and then adjust the servo valve to control the air pressure of the air spring according to the weight of the precision instrument to ensure that the load-bearing requirements can be met. Then place the precision instrument on the top plate, and then control the current of coil A and coil B respectively through the controller, thereby controlling the strength of the electromagnetic field generated by them, and then controlling the attractive force between permanent magnet A and the repulsive force between permanent magnet B respectively, thereby adjusting the positive and negative stiffness of the system, so that the system reaches static quasi-zero stiffness at the initial equilibrium position; Vibration signals are collected by vertical acceleration sensor, vertical position sensor, lateral acceleration sensor A, lateral position sensor A, lateral acceleration sensor B and lateral position sensor B, and then the signals are transmitted to the controller; in case of vertical high-frequency vibration source, the first vibration reduction is first achieved by air spring, and secondly, the second vibration reduction is achieved by vertical springs in parallel, and finally, the current of coil A and coil B can be controlled by the controller respectively, so as to control the strength of electromagnetic field generated by them, and then the attractive force between permanent magnet A and repulsive force between permanent magnet B can be controlled respectively, so as to further achieve the third vibration reduction; in case of vertical low-frequency vibration source, the parallel vertical voice coil motors are controlled by the controller respectively to achieve vibration reduction; in case of horizontal high-frequency vibration source, the first vibration reduction is first achieved by rocker arm, and then the second vibration reduction is achieved by horizontal spring A and horizontal spring B in parallel up and down; in case of horizontal low-frequency vibration source, the horizontal voice coil motor A and horizontal voice coil motor B in parallel up and down are controlled by the controller respectively to achieve vibration reduction.

2. The variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The magnetic poles of the permanent magnet A and the permanent magnet B are in the same direction, and the currents of the coil A and the coil B are in opposite directions. After power is turned on, the magnetic fields generated by the permanent magnet A and the coil A show an attractive force, and the magnetic fields generated by the permanent magnet B and the coil B show a repulsive force.

3. The variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The shell is in a rectangular structure and has magnetic isolation performance. An opening is arranged on the top of the shell, and a certain gap is maintained between the swing rod and the shell while passing through the opening.

4. The variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The swing rod is a flexible swing rod.

5. The variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The vertical spring, transverse spring A and transverse spring B are all metal springs.

6. The variable stiffness three-degree-of-freedom quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The inner side of the shell is also equipped with a frame A and a frame B for mounting coil A and coil B respectively.

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

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