Split type self-sensing piezoelectric active vibration reduction table

Abstract

The invention discloses a split type self-sensing piezoelectric active vibration reduction table, and belongs to the technical field of vibration suppression and isolation. The vibration reduction table comprises two vibration isolation units which are in central symmetry and parallel to each other, each vibration isolation unit comprises two axisymmetric vibration reduction units, each vibration reduction unit comprises a passive vibration reduction unit and an active vibration reduction unit, the passive vibration isolation units are used for achieving high-frequency attenuation of the vibration reduction table, and the active vibration isolation units are used for achieving active control of the vibration reduction table. A piezoelectric acceleration sensor and a piezoelectric actuator in the active vibration isolation unit jointly form a self-sensing piezoelectric active vibration reduction device, and the self-sensing piezoelectric active vibration reduction device not only can sense the change of the environment or the self-state, but also can actively adjust the self-behavior or the self-state according to the sensing result. A vibration reduction technology combining passive vibration isolation and active vibration reduction is adopted, high-frequency vibration can be comprehensively isolated, low-frequency vibration can be effectively restrained, the low-frequency vibration transmissibility is guaranteed, meanwhile, the high attenuation rate of high-frequency vibration is provided, full decoupling of six-degree-of-freedom control can be achieved, and application is flexible.

Description

Technical Field

[0001] This invention belongs to the field of vibration isolation and control technology, and in particular relates to a split-type self-sensing piezoelectric active vibration damping table. Background Technology

[0002] With the development of cutting-edge scientific research fields such as precision manufacturing and processing, precision optoelectronic equipment, and aerospace technology, relevant personnel and institutions have begun to place more stringent requirements on the stability of system structures and the accuracy of measurement and processing. A key factor limiting the improvement of structural stability and system accuracy has always been the influence of vibration interference, especially the influence of low-frequency, minute vibrations. In fact, the influence of these minute vibrations has become a bottleneck for many cutting-edge technology applications. High-performance vibration isolation technology solves the problem of minute vibrations affecting the normal operation of precision equipment by isolating environmental micro-vibrations and providing an ultra-stable working environment.

[0003] Active control systems can precisely counteract low-frequency vibrations, while split structures suppress high-frequency vibrations through mechanical decoupling, covering low-frequency scenarios that are difficult to handle with traditional passive vibration isolation. Traditional air-bearing vibration isolation tables rely on a stable air source and cannot suppress low-frequency vibrations; passive vibration isolation systems typically have a high resonant frequency, and due to the contradiction between the natural frequency and static stiffness, it is difficult to further reduce its natural frequency. Summary of the Invention

[0004] In view of this, in order to solve the problems that traditional air-bearing vibration isolation tables rely on a stable air source and cannot suppress low-frequency vibrations; and that the resonant frequency of passive vibration isolation systems is usually high, and it is difficult to further reduce the natural frequency due to the contradiction between the natural frequency and the static stiffness, this invention proposes a split-type self-sensing piezoelectric active vibration reduction table.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a split-type self-sensing piezoelectric active vibration damping table, comprising two centrally symmetrical parallel vibration isolation units, each vibration isolation unit comprising two axisymmetric vibration damping units, each vibration damping unit comprising a passive vibration damping unit and an active vibration damping unit, wherein the passive vibration isolation unit comprises a metal spring assembly, a damping base, a top plate and a bottom plate, the metal spring assembly being mounted on the damping base, and the metal spring assembly being connected to the top plate and the bottom plate respectively at the top and bottom; The active vibration damping unit includes a vertical drive mechanism and a horizontal drive mechanism, which are mounted on the top plate. The vertical drive mechanism includes a vertical piezoelectric actuator and a vertical acceleration piezoelectric sensor, with the vertical acceleration piezoelectric sensor having the vertical piezoelectric actuator mounted on it. The horizontal drive mechanism includes a horizontal acceleration piezoelectric sensor and a horizontal piezoelectric actuator, with the horizontal acceleration piezoelectric sensor having the horizontal piezoelectric actuator mounted in front of it.

[0006] Furthermore, the metal spring assembly includes a metal spring and an adjustment mechanism. The metal spring is mounted on a rubber damping base and serves as a load-bearing element and provides passive vibration isolation. The adjustment mechanism is connected to the base plate via bolts and is used to adjust the height and level of the top plate.

[0007] Furthermore, the metal spring is provided with a damping plate.

[0008] Furthermore, the horizontal and vertical acceleration piezoelectric sensors are used to measure vibration signals from the base plate.

[0009] Furthermore, the horizontal and vertical piezoelectric actuators are used as force actuators to output damping force in real time, thereby achieving active vibration reduction.

[0010] Furthermore, the controller is used to calculate the vibration signals collected by the acceleration piezoelectric sensor and output them to the piezoelectric actuator.

[0011] Furthermore, the horizontal drive mechanism is fixedly connected to the top plate via a fixed plate and a crossbeam.

[0012] Furthermore, the two horizontal drive mechanisms within each vibration isolation unit are arranged orthogonally.

[0013] Furthermore, a right-angled triangular prism adapter is installed on the base plate. The right-angled triangular prism adapter is located at the intersection of the extension lines of the two horizontal driving and measuring mechanisms within each vibration isolation unit, and is in contact with both of them.

[0014] Furthermore, each set of piezoelectric actuators and accelerometers are placed in the same direction and rigidly connected by copper discs to form a driving and sensing unit. In the static state, the two copper discs are parallel to the two right-angled faces of the right-angled triangular prism adapter connected to the base plate. Compared with existing technologies, the advantages of the split-type self-sensing piezoelectric active vibration damping table described in this invention are: 1. The split-type self-sensing piezoelectric active vibration damping table of the present invention adopts a vibration damping technology that combines passive vibration isolation and active vibration damping. It can not only completely isolate high-frequency vibration, but also effectively suppress low-frequency vibration, ensuring the low-frequency vibration transmission rate, while providing a high attenuation rate for high-frequency vibration. The lowest natural frequency can be lower than 3Hz. It can also achieve full decoupling of six-degree-of-freedom control, making it flexible in application.

[0015] 2. This invention employs a split structure, which allows for asymmetrical layout to avoid uneven ground or spatial obstacles. The split vibration isolation table consists of multiple independent units that can be freely combined or expanded according to actual needs. Future upgrades to the system performance can be achieved by adding modules (such as active vibration isolation units) without redesigning the entire platform. Each independent module allows for individual adjustment of parameters such as stiffness and damping, enabling differentiated optimization for different directions (such as vertical / horizontal vibration) and improving overall vibration isolation efficiency.

[0016] 3. This invention allows for distributed load-bearing, reducing the load pressure on individual units, making it suitable for the long-term stable operation of large equipment (such as electron microscopes and lithography machines). It can be used in various application scenarios such as optical experiments, precision measurement, microelectronics manufacturing and testing, precision processing equipment, microscopic imaging and cell manipulation, and medical equipment. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a three-dimensional structural diagram of a split-type self-sensing piezoelectric active vibration damping table according to the present invention; Figure 2 This is a diagram showing the arrangement of sensors and actuators in a split-type self-sensing piezoelectric active vibration damping table according to the present invention. Figure 3 This is a top view of a split-type self-sensing piezoelectric active vibration damping table according to the present invention; Figure 4 This is a schematic diagram of the passive vibration isolation principle used in this invention; Figure 5 This is a schematic diagram of the active vibration reduction principle used in this invention; Figure 6 This is a schematic diagram of a split-type metal spring active vibration damping table according to the present invention; Figure 7 The transmissivity curve (z-direction) of the split-type metal spring active vibration damping table has been changed. Figure 8 The transmissivity curve (x-direction) of the split-type metal spring active vibration damping table; Figure 9 The transmissivity curve (y-direction) of the split-type metal spring active vibration damping table; In the diagram: 1-Damping plate, 2-Spring, 3-Damping base, 4-Horizontal acceleration piezoelectric sensor, 5-Horizontal piezoelectric actuator, 6-Fixed plate, 7-Crossbeam, 8-Vertical piezoelectric actuator, 9-Vertical acceleration piezoelectric sensor, 10-Triangular prism adapter, 11-Baffle, 12-Side plate, 13-Adjustment mechanism, 14-Top plate, 15-Bottom plate, 16-Vertical drive mechanism a, 17-Horizontal drive mechanism a, 18-Horizontal drive mechanism b, 19-Vertical drive mechanism b, 20-Vertical drive mechanism c, 21-Horizontal drive mechanism c, 22-Horizontal drive mechanism d, 23-Vertical drive mechanism d. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0019] See Figure 1-9 This embodiment describes a split-type self-sensing piezoelectric active vibration damping platform, which includes two centrally symmetrical, parallel vibration isolation units. Each damping platform includes two axisymmetric damping units, and each damping unit includes a passive damping unit and an active damping unit.

[0020] The passive vibration isolation unit is used to achieve high-frequency attenuation of the vibration damping table. It includes a metal spring assembly, a damping base 3, a top plate 14 and a bottom plate 15. The metal spring assembly is installed on the damping base 3 and is connected to the top plate 14 and the bottom plate 15 at the top and bottom, respectively.

[0021] The metal spring assembly includes a metal spring 2 and an adjustment mechanism 13. The metal spring 2 is mounted on a rubber damping base 3 and serves as a load-bearing element and passive vibration isolation. The adjustment mechanism 13 is connected to the base plate 15 by bolts and is used to adjust the height and level of the top plate 14. A damping plate 1 is provided on the metal spring 2.

[0022] The adjustment mechanism 13 is a column with bolt holes, which ensures that the displacement during vibration is constrained. At the same time, it assists in centering during installation, ensuring that the top plate 14 and the bottom plate 15 are aligned, improving assembly accuracy, reducing uneven load caused by drift, and optimizing the initial working state of the vibration isolator by adjusting the distance between the top plate 14 and the bottom plate 15.

[0023] The top plate 14 and bottom plate 15 of the vibration isolation unit are connected by a spring 2. The pre-compression spring 2 can also be used to adapt to different load weights. The relative displacement between the top plate 14 and bottom plate 15 can be made within a limited range by the adjustment mechanism.

[0024] The active vibration damping unit is used to realize the active control of the vibration damping table, including a vertical drive mechanism and a horizontal drive mechanism. The vertical drive mechanism and the horizontal drive mechanism are installed on the top plate 14. The vertical drive mechanism includes a vertical piezoelectric actuator 8 and a vertical acceleration piezoelectric sensor 9. The vertical acceleration piezoelectric sensor 9 is equipped with the vertical piezoelectric actuator 8. The horizontal drive mechanism includes a horizontal acceleration piezoelectric sensor 4 and a horizontal piezoelectric actuator 5. The horizontal acceleration piezoelectric sensor 4 is equipped with the horizontal piezoelectric actuator 5 in front of it.

[0025] The two horizontal driving and measuring mechanisms within each vibration isolation unit are arranged orthogonally. A right-angled triangular prism adapter 10 is installed on the base plate 15. The right-angled triangular prism adapter 10 is located at the intersection of the extension lines of the two horizontal driving and measuring mechanisms within each vibration isolation unit and is in contact with both of them, serving as an output point of the horizontal driving and measuring unit.

[0026] The acceleration piezoelectric sensor is used to measure the vibration signal from the base plate 15. It is mounted on the piezoelectric acceleration sensor base, which is fixedly connected to the base plate 15. The controller is used to calculate the vibration signal collected by the acceleration piezoelectric sensor and output it to the piezoelectric actuator. The piezoelectric actuator is used as a force actuator to output damping force in real time to achieve active vibration reduction.

[0027] A piezoelectric actuator combined with an accelerometer piezoelectric sensor forms a self-sensing unit. This design breaks the traditional architecture of separating "sensor" and "actuator" in the system. By achieving "sensing-execution integration" through structural design, it can significantly improve the system's compactness, response speed and energy efficiency.

[0028] The method of using the split-type self-sensing piezoelectric active vibration damping table described in this invention is as follows: The load is placed on the top plate 14, and the passive vibration isolation unit achieves passive vibration reduction through the mass-spring-damping principle. The specific principle is as follows: Figure 4 As shown: X0 and X1 represent the displacements of the foundation and the load, respectively. For total load mass, For the overall system stiffness, Let be the system damping. Under no external force input, the open-loop transmissivity of this system is as follows:

[0029] There are three stages as the frequency changes: At low frequencies, the foundation vibrates very slowly (very low frequency), or the vibration isolator is very stiff (high natural frequency). The spring is slowly compressed and stretched, and the mass block moves almost synchronously with the foundation, resulting in no vibration isolation effect.

[0030] When the external vibration frequency approaches the system's natural frequency, resonance occurs, and the vibration amplitude of the mass block is drastically amplified, far exceeding the amplitude of the base vibration. A peak appears on the transmissibility curve, potentially much greater than 1. Damping becomes crucial at this point. Greater damping suppresses the resonance peak, preventing equipment damage due to resonance. However, excessive damping prolongs the system's settling time.

[0031] The external vibration frequency is high enough. The result from the above equation is that the mass block remains almost stationary, while the spring and damper violently expand and contract and dissipate energy between the foundation and the mass. The effective vibration isolation zone is reached; the higher the frequency, the better the vibration isolation effect.

[0032] The active vibration isolation unit transmits the load vibration signal to the controller through an acceleration piezoelectric sensor. After the controller calculates and converts the signal, it outputs it to the piezoelectric actuator. The actuator outputs damping force through feedback control, thereby eliminating or reducing the impact of foundation vibration on the vibration-damped equipment.

[0033] As attached Figure 2 The piezoelectric actuator and the accelerometer piezoelectric sensor are placed in the same direction and rigidly connected by copper discs, forming a single drive-sensor unit. Each vibration isolation unit includes four drive-sensor units fixed to the top plate of the isolation unit, acting in the vertical and horizontal directions respectively. The two sets of horizontal drive-sensor units are placed orthogonally. In the static state, the two copper discs are parallel to the two right-angled faces of the right-angled triangular prism adapter 10 connected to the base plate 15, and together with the two vertical drive-sensor units, they contact the base plate 15 through variable-direction copper discs. The horizontal drive-sensor mechanism is fixedly connected to the top plate 14 through the fixing plate 6 and the crossbeam 7. This structure ensures a 6-degree-of-freedom vibration isolation effect.

[0034] The variable orientation of the copper disc means that it can have a slight angular change. The function of the copper disc is to transmit force. The variable orientation is to ensure that all six degrees of freedom have a good vibration isolation effect and to ensure that there is still good contact when there is a change in rotational degree of freedom.

[0035] As attached Figure 3 The base plate 15 is fixed to the ground, and the two vibration isolation units are placed in parallel. The side plates 12 and the base plate 15 are used to enclose the vibration isolation units to prevent debris from falling into them. Load plates are placed on the top plates 14 of the two vibration isolation units to bear the load.

[0036] Figure 4 The passive vibration isolation principle used in this invention achieves vibration isolation through mass-spring-damping.

[0037] Figure 5 The active vibration reduction principle used in this invention is to transmit the load vibration signal to the controller through an acceleration piezoelectric sensor. After the controller calculates and converts the signal, it is output to the actuator. The actuator outputs damping force through feedback control, thereby eliminating or reducing the impact of foundation vibration on the equipment being vibration reduced.

[0038] Figure 6 This is a schematic diagram of the split-type metal spring active vibration damping table provided by the present invention. Mass-spring-damping represents the passive vibration isolation unit, and sensor-controller-actuator represents the active vibration damping unit. The present invention employs a vibration reduction technology combining passive isolation and active vibration damping. In the active vibration damping unit, a feedforward sensor monitors foundation vibration, and a feedback sensor monitors the vibration of the equipment being damped. A combined feedback and feedforward control technology is used to eliminate or reduce the impact of vibration on the load.

[0039] Figure 7 The transmissivity curve of the active vibration damping platform is shown in the figure. As can be seen from the figure, passive vibration isolation effectively attenuates high-frequency vibrations, but has little effect on low-frequency vibrations, especially near the resonance point, where the vibration not only fails to be attenuated but actually increases, forming a resonance peak. Active vibration damping effectively reduces low-frequency vibrations, with a particularly significant suppression effect near the resonance point. After adopting a combined feedback and feedforward control technology, the transmissivity in the low-frequency band is significantly reduced again. For different actual foundation vibrations, the feedforward parameters can be adaptively adjusted, allowing the feedforward control to move specifically within the controlled bandwidth, thus improving the practicality and effectiveness of vibration damping.

[0040] The split-type self-sensing piezoelectric active vibration damping stage of this invention employs a vibration damping technology that combines passive vibration isolation with active vibration damping. This technology can comprehensively isolate high-frequency vibrations while effectively suppressing low-frequency vibrations, ensuring low-frequency vibration transmission rate, and simultaneously providing a high attenuation rate for high-frequency vibrations. In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating orientation and positional relationships are based on the orientation and positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0041] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A split-type self-sensing piezoelectric active vibration damping table, characterized in that: It includes two centrally symmetrical parallel vibration isolation units. Each vibration isolation unit includes two axisymmetric damping units. Each damping unit includes a passive damping unit and an active damping unit. The passive vibration isolation unit includes a metal spring assembly, a damping base (3), a top plate (14), and a bottom plate (15). The metal spring assembly is installed on the damping base (3). The metal spring assembly is connected to the top plate (14) and the bottom plate (15) respectively. The active vibration reduction unit includes a vertical drive mechanism and a horizontal drive mechanism. The vertical drive mechanism and the horizontal drive mechanism are installed on the top plate (14). The vertical drive mechanism includes a vertical piezoelectric actuator (8) and a vertical acceleration piezoelectric sensor (9). The vertical acceleration piezoelectric sensor (9) is equipped with the vertical piezoelectric actuator (8). The horizontal drive mechanism includes a horizontal acceleration piezoelectric sensor (4) and a horizontal piezoelectric actuator (5). The horizontal acceleration piezoelectric sensor (4) is equipped with the horizontal piezoelectric actuator (5) in front of it.

2. The split-type self-sensing piezoelectric active vibration damping table according to claim 1, characterized in that: The metal spring assembly includes a metal spring (2) and an adjustment mechanism (13). The metal spring (2) is mounted on a rubber damping base (3) and is used to bear load and achieve passive vibration isolation. The adjustment mechanism (13) is connected to the base plate (15) by bolts and is used to achieve height adjustment and horizontal adjustment of the top plate (14).

3. The split-type self-sensing piezoelectric active vibration damping table according to claim 2, characterized in that: The metal spring (2) is provided with a damping plate (1).

4. The split-type self-sensing piezoelectric active vibration damping table according to claim 1, characterized in that: The horizontal acceleration piezoelectric sensor (4) and the vertical acceleration piezoelectric sensor (9) are used to measure vibration signals from the base plate (15).

5. The split-type self-sensing piezoelectric active vibration damping table according to claim 1, characterized in that: The horizontal piezoelectric actuator (5) and the vertical piezoelectric actuator (8) are used as force actuators to output damping force in real time and achieve active vibration reduction.

6. The split-type self-sensing piezoelectric active vibration damping table according to claim 1, characterized in that: The controller is used to calculate the vibration signals collected by the accelerometer piezoelectric sensor and output them to the piezoelectric actuator.

7. The split-type self-sensing piezoelectric active vibration damping table according to claim 1, characterized in that: The horizontal drive mechanism is fixedly connected to the top plate (14) through the fixed plate (6) and the crossbeam (7).

8. The split-type self-sensing piezoelectric active vibration damping table according to claim 1, characterized in that: The two horizontal drive mechanisms within each vibration isolation unit are arranged orthogonally.

9. The split-type self-sensing piezoelectric active vibration damping table according to claim 1 or 8, characterized in that: A right-angled triangular prism adapter (10) is installed on the base plate (15). The right-angled triangular prism adapter (10) is located at the intersection of the extension lines of the two horizontal driving and measuring mechanisms in each vibration isolation unit and is in contact with both.

10. The split-type self-sensing piezoelectric active vibration damping table according to claim 1, characterized in that: Each set of piezoelectric actuators and acceleration piezoelectric sensors are placed in the same direction and are rigidly connected by copper discs to form a driving and measuring unit. In the static state, the two copper discs are parallel to the two right-angled surfaces of the right-angled triangular prism adapter (10) connected to the base plate (15).

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