Piezoelectric vibration isolator and control system thereof

Abstract

The invention relates to a piezoelectric vibration isolator and a control system thereof, the piezoelectric vibration isolator comprises a shell unit, the shell unit comprises a shell and an end cover, one end of the shell is provided with an opening, and the end cover is detachably arranged in the opening; the bearing unit is arranged on the end cover, the bearing unit comprises a bearing platform and a first sensor assembly, the first sensor assembly is installed on the bearing platform, and the bearing platform is used for bearing a load; the middle mass unit is connected with the bearing platform, the middle mass unit is contained in the shell, the middle mass unit comprises a middle mass block and a second sensor assembly, and the second sensor assembly is installed on the middle mass block; and the passive vibration isolation unit is arranged in the shell, the passive vibration isolation unit is connected with the bearing platform, and the passive vibration isolation unit is further connected with the middle mass unit. The high vibration isolation efficiency can be obtained, the gain margin of the system is improved, and the stability of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration isolation devices, and in particular to a piezoelectric vibration isolator and its control system. Background Art

[0002] The disturbances of precision instruments come from two aspects. One is ground disturbance, and the other is the movement of internal moving parts of the instrument. The role of the vibration isolator is to counteract ground disturbances and internal interference of the equipment to be vibration-isolated. Piezoelectric material characteristics: Piezoelectric ceramics will generate mechanical deformation (inverse piezoelectric effect) when an electric field is applied, and vice versa, generate charges under mechanical stress (direct piezoelectric effect). In an active vibration isolation system, the inverse piezoelectric effect is mainly used to generate a force to counteract vibration. Specifically, a piezoelectric active vibration isolator is a device that uses the inverse piezoelectric effect of piezoelectric materials to achieve active vibration control to isolate the interference of external vibration to sensitive equipment; it is widely used in fields such as precision measurement instruments, aerospace, and semiconductor manufacturing, and its functions include vibration isolation of lithography machines and electron microscopes, and stabilization of precision optical systems. In the prior art, traditional passive vibration isolation devices rely on low-frequency (such as 1 - 10 Hz) rubber or air springs and cannot effectively isolate medium-high frequency (such as 50 - 500 Hz) vibrations. The bottleneck of active vibration isolation devices lies in that the load is directly coupled with the actuator, and the system resonance frequency may fall within the control bandwidth, resulting in a decrease in robustness.

[0003] The deficiency of the prior art is that if the load directly falls on the piezoelectric stack, the system resonance frequency may drop to around 100 Hz (determined by the load mass and piezoelectric stiffness). At this time, the control bandwidth will overlap with the resonance peak, resulting in phase lag, insufficient gain margin, and even system instability. Summary of the Invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a piezoelectric vibration isolator and its control system. By setting an intermediate mass block, a control bandwidth exceeding 100 Hz can be obtained, thereby obtaining a higher vibration isolation efficiency, improving the system gain margin, and enhancing the stability of the system.

[0005] To solve the above technical problem, the present invention provides a piezoelectric vibration isolator, comprising a housing unit, which includes a housing and an end cover. One end of the housing has an opening, and the end cover is detachably arranged at the opening; a bearing unit, which is arranged on the end cover. The bearing unit includes a bearing platform and a first sensor assembly. The first sensor assembly is installed on the bearing platform, and the bearing platform is used to bear the load; An intermediate mass unit, which is connected to the bearing platform, is received in the housing. The intermediate mass unit includes an intermediate mass block and a second sensor assembly, and the second sensor assembly is installed on the intermediate mass block. A passive vibration isolation unit is disposed in the housing. The passive vibration isolation unit is connected to the bearing platform and, at the same time, is also connected to the intermediate mass unit. A piezoelectric actuation unit is disposed in the housing. The piezoelectric actuation unit includes a first piezoelectric stack mechanism, a second piezoelectric stack mechanism, and a preloading mechanism. The first piezoelectric stack mechanism can bear vibrations in the horizontal direction, and the second piezoelectric stack mechanism can bear vibrations in the height direction. The preloading mechanism is disposed opposite to the first piezoelectric stack mechanism. One end of the preloading mechanism is connected to the intermediate mass block, and the other end is connected to the housing to keep the first piezoelectric stack mechanism in a compressed state. A controller unit is electrically connected to the bearing unit, the intermediate mass unit, and the piezoelectric actuation unit. The controller unit can receive vibration signals, and after conversion, output electrical signals to the piezoelectric actuation unit. Among them, the piezoelectric actuation unit and the intermediate mass block form a high-frequency vibration system to isolate vibrations within the control bandwidth. The passive vibration isolation unit and the load form a low-frequency vibration system to passively isolate vibrations outside the bandwidth.

[0006] In an embodiment of the present invention, the intermediate mass block has a first surface, a second surface, a third surface, and a fourth surface connected in sequence. The first surface, the second surface, the third surface, and the fourth surface form the side wall of the intermediate mass block. The first piezoelectric stack mechanism interacts with the first surface and the second surface respectively. The second piezoelectric stack mechanism is disposed between the lower surface of the intermediate mass block and the housing, and the second piezoelectric stack mechanism interacts with the lower surface of the intermediate mass block.

[0007] In an embodiment of the present invention, the first piezoelectric stack mechanism includes a first stack block and a second stack block. The first stack block abuts against the first surface, and the second stack block abuts against the second surface. The second piezoelectric stack mechanism includes a third stack block, and the third stack block abuts against the intermediate mass block.

[0008] In an embodiment of the present invention, the piezoelectric actuation unit further includes a flexible decoupling mechanism, which is disposed between the intermediate mass block and the first piezoelectric stack mechanism, between the intermediate mass block and the second piezoelectric stack mechanism, and between the intermediate mass block and the preloading mechanism.

[0009] In an embodiment of the present invention, the preloading mechanism includes a first preloading component and a second preloading component. The first preloading component is disposed on the opposite side of the first stacking block, and the second preloading component is disposed on the opposite side of the second stacking block. The first preloading component includes a first elastic member and a first fastener, and the second preloading component includes a second elastic member and a second fastener.

[0010] In an embodiment of the present invention, the first sensor assembly includes a first sensor, a second sensor, and a third sensor. The first sensor is used to monitor the movement of the bearing platform along the first horizontal direction, the second sensor is used to monitor the movement of the bearing platform along the second horizontal direction, and the third sensor is used to monitor the movement of the bearing platform along the height direction.

[0011] In an embodiment of the present invention, the second sensor assembly includes a fourth sensor, a fifth sensor, and a sixth sensor. The fourth sensor is used to monitor the movement of the intermediate mass block along the first horizontal direction, the fifth sensor is used to monitor the movement of the intermediate mass block along the second horizontal direction, and the sixth sensor is used to monitor the movement of the intermediate mass block along the height direction.

[0012] In an embodiment of the present invention, the passive vibration isolation unit includes a passive vibration isolation block made of an elastic material. The passive vibration isolation block includes a first connection block and a second connection block connected to each other. The first connection block is connected to the bearing platform, and the second connection block is connected to the intermediate mass block. The first connection block and the second connection block are symmetric to each other, and the cross-sections of the first connection block and the second connection block are trapezoidal.

[0013] In an embodiment of the present invention, a plurality of mounting holes are formed in the side wall of the housing, and the preloading mechanism and the piezoelectric stacking mechanism are respectively assembled to the housing through the mounting holes.

[0014] The present invention also provides a control system for a piezoelectric vibration isolator, including The piezoelectric vibration isolator as described above; A signal output terminal; An outer loop control circuit, which includes an outer loop controller. The outer loop controller is connected to the first sensor assembly of the bearing unit and can output a first signal to the signal output terminal; An inner loop control circuit, which includes an inner loop controller. The inner loop controller is connected to the second sensor assembly of the intermediate mass unit and can output a second signal to the signal output terminal; A feedforward control circuit, which includes a feedforward controller. The feedforward controller is connected to the ground sensor and can output a third signal to the signal output terminal; The outer loop control circuit is used to compensate for the gain of the resonance frequency of the inner loop control circuit. After the ground vibration is output from the ground sensor to the feedforward controller, it is superimposed and output to the signal output terminal.

[0015] The above technical solution of the present invention has the following advantages compared with the prior art: A piezoelectric vibration isolator according to the present invention is provided with a housing unit, a bearing unit, an intermediate mass unit, a passive vibration isolation unit, a piezoelectric actuation unit and a controller unit. Among them, the bearing unit includes a bearing platform for installing the load. The passive vibration isolation unit, the intermediate mass unit and the piezoelectric actuation unit are housed in the housing unit. The piezoelectric actuation unit and the intermediate mass block cooperate with each other to form a high-frequency vibration system to isolate vibrations within the control bandwidth; the passive vibration isolation unit and the load cooperate with each other to form a low-frequency vibration system to passively isolate vibrations outside the bandwidth. By setting the intermediate mass block, the piezoelectric vibration isolator of the present invention can obtain a relatively high (exceeding 100 Hz) control bandwidth, thereby obtaining a relatively high vibration isolation efficiency, improving the system gain margin, and enhancing the stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein.

[0017] Figure 1 is a schematic diagram of the overall structure of the preferred embodiment of the present invention.

[0018] Figure 2 is Figure 1 an exploded view of

[0019] Figure 3 is a schematic diagram of the structure of the intermediate mass block of the preferred embodiment of the present invention.

[0020] Figure 4 is a schematic diagram of the structure of the intermediate mass unit of the preferred embodiment of the present invention.

[0021] Figure 5 is a schematic diagram of the structure of the bearing unit of the preferred embodiment of the present invention.

[0022] Figure 6 is an exploded view of the structure of the piezoelectric actuation unit of the preferred embodiment of the present invention.

[0023] Figure 7 is a top view schematic diagram of the piezoelectric actuation unit of the preferred embodiment of the present invention.

[0024] Figure 8 is a schematic diagram of the passive vibration isolation block of the preferred embodiment of the present invention.

[0025] Figure 9 It is a schematic structural diagram of the control system according to the preferred embodiment of the present invention.

[0026] Figure 10 It is a frequency monitoring data graph in the specific implementation process of the present invention.

[0027] Figure 11 It is a frequency monitoring waveform graph in the specific implementation process of the present invention.

[0028] Description of the reference numerals in the drawings of the specification: 1. Outer shell unit; 10. Housing; 11. End cover; 20. Carrying platform; 21. First sensor; 22. Second sensor; 23. Third sensor; 30. Intermediate mass block; 301. First surface; 3010. First mounting groove; 302. Second surface; 3020. Second mounting groove; 303. Third surface; 3030. Third mounting groove; 304. Fourth surface; 3040. Fourth mounting groove; 31. Fourth sensor; 32. Fifth sensor; 33. Sixth sensor; 4. Passive vibration isolation unit; 51. First piezoelectric stacking mechanism; 511. First stacking block; 512. Second stacking block; 513. First piezoelectric cover plate; 514. Second piezoelectric cover plate; 52. Second piezoelectric stacking mechanism; 521. Third stacking block; 53. Pre-tightening mechanism; 530. First pre-tightening assembly; 5301. First elastic member; 5302. First fastener; 5303. First pre-tightening cover plate; 531. Second pre-tightening assembly; 5311. Second elastic member; 5312. Second fastener; 5313. Second pre-tightening cover plate; 541. First gasket; 542. Second gasket; 543. Third gasket; 544. Fourth gasket; 545. Fifth gasket; 6. Passive vibration isolation block; 61. First connecting block; 62. Second connecting block. Detailed implementation manners

[0029] The present invention will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention. Embodiment 1

[0030] Referring to Figures 1 to 8 As shown, the present invention discloses a piezoelectric vibration isolator, which can be applied to the fields of high-precision measurement and high-precision instrument vibration isolation.

[0031] The piezoelectric vibration isolator includes an outer shell unit 1, the outer shell unit 1 includes a housing 10 and an end cover 11, one end of the housing 10 in the height direction has an opening, a receiving space is formed inside the housing 10, and the end cover 11 is detachably arranged at the opening.

[0032] The piezoelectric vibration isolator further includes a bearing unit disposed on the end cap 11. The bearing unit includes a bearing platform 20 and a first sensor assembly. An installation through hole is formed in the end cap 11. The bearing platform 20 is disposed in the installation through hole, and the first sensor assembly is installed on the bearing platform 20. The bearing platform 20 is used to bear a load.

[0033] The piezoelectric vibration isolator further includes an intermediate mass unit received in the housing 10. The intermediate mass unit is connected to the bearing platform 20. Specifically, the bearing platform 20 and the intermediate mass unit can be connected by bolts.

[0034] The intermediate mass unit includes an intermediate mass block 30 and a second sensor assembly. The second sensor assembly is installed on the intermediate mass block 30.

[0035] The piezoelectric vibration isolator further includes a passive vibration isolation unit 4 disposed in the housing 10. One end of the passive vibration isolation unit 4 in the height direction is connected to the bearing platform 20, and at the same time, the other end of the passive vibration isolation unit 4 in the height direction is connected to the intermediate mass block 30. The passive vibration isolation unit 4 is used to isolate high-frequency vibrations so as to obtain an appropriate frequency. In the present invention, after the passive vibration isolation unit 4 bears a load, the resonance frequencies in the horizontal and vertical directions are 15 - 40 Hz.

[0036] The piezoelectric vibration isolator further includes a piezoelectric actuation unit disposed in the housing 2. The piezoelectric actuation unit includes a first piezoelectric stack mechanism 51, a second piezoelectric stack mechanism 52, and a pre-tightening mechanism 53. Among them, the first piezoelectric stack mechanism 51 can bear vibrations in the horizontal direction, and the second piezoelectric stack mechanism 52 can bear vibrations in the height direction. Specifically, with the intermediate mass block 30 as the center, the pre-tightening mechanism 53 is disposed opposite to the first piezoelectric stack mechanism 51. One end of the pre-tightening mechanism 53 is connected to the intermediate mass block 30, and the other end is connected to the housing 10 so that the first piezoelectric stack mechanism 51 can maintain a compressed state.

[0037] In detail, the bearing unit, the passive vibration isolation unit, and the intermediate mass unit are sequentially disposed in the housing 10 in the height direction.

[0038] The piezoelectric vibration isolator further includes a controller unit electrically connected to the bearing unit, the intermediate mass unit, and the piezoelectric actuation unit. The controller unit can receive vibration signals, perform internal conversion, and then output electrical signals to the piezoelectric actuation unit to make the piezoelectric actuation unit act, so as to cancel vibrations from different directions and achieve the purpose of vibration isolation.

[0039] Among them, the piezoelectric actuating unit and the intermediate mass block 30 cooperate with each other to form a high-frequency vibration system for isolating vibrations within the control bandwidth; the passive vibration isolation unit 4 cooperates with the load to form a low-frequency vibration system for passively isolating vibrations outside the bandwidth.

[0040] During operation, at least three of the piezoelectric vibration isolators are used. The lower part of the piezoelectric vibration isolator is installed on the ground foundation or a high-rigidity frame, and the upper part supports the load. Thus, the piezoelectric vibration isolator and the load together form a two-degree-of-freedom system. Assuming that the ground generates a vertical upward disturbance, the second piezoelectric stacking mechanism 52 will be compressed. At this time, the controller unit will generate a voltage and apply it to the piezoelectric actuating unit, prompting it to generate a reverse displacement to superimpose with the disturbance on the ground to eliminate vibrations in the vertical direction and ensure that the spatial position of the vibration-isolated object remains unchanged. The vibration isolation principle in the horizontal direction is the same.

[0041] It can be seen from this that a piezoelectric vibration isolator to be protected by the present invention is provided with a housing unit, a bearing unit, an intermediate mass unit, a passive vibration isolation unit, a piezoelectric actuating unit, and a controller unit. Among them, the bearing unit includes a bearing platform for installing the load. The passive vibration isolation unit, the intermediate mass unit, and the piezoelectric actuating unit are accommodated in the housing unit. The piezoelectric actuating unit and the intermediate mass block cooperate with each other to form a high-frequency vibration system for isolating vibrations within the control bandwidth; the passive vibration isolation unit and the load cooperate with each other to form a low-frequency vibration system for passively isolating vibrations outside the bandwidth; by setting the intermediate mass block, the piezoelectric vibration isolator of the present invention can obtain a relatively high (exceeding 100 Hz) control bandwidth, and thus obtain a relatively high vibration isolation efficiency, improve the system gain margin, and enhance the stability of the system.

[0042] As a preferred implementation manner, the bearing platform 20 has high rigidity. Generally speaking, it can be processed from metal parts such as aluminum or steel. Of course, the material of the bearing platform 20 is not limited to metal materials, and can also be non-metal materials such as marble and ceramics.

[0043] In addition, the shape of the cross-section of the bearing platform 20 includes but is not limited to a circle.

[0044] Specifically, the first piezoelectric stacking mechanism 51 is used to control vibrations in the horizontal direction; the second piezoelectric stacking mechanism 52 is used to control vibrations in the vertical direction.

[0045] As a preferred implementation manner, the intermediate mass block 4 generally adopts a regular hexahedron in shape, and the material is preferably aluminum or stainless steel. The weight of the intermediate mass block 30 is 10 - 30 kg.

[0046] Further, the intermediate mass block 30 has a first surface 301, a second surface 302, a third surface 303, and a fourth surface 304 that are sequentially connected, and the first surface 301, the second surface 302, the third surface 303, and the fourth surface 304 together form the side wall of the intermediate mass block 30.

[0047] Specifically, the first piezoelectric stacking mechanism 51 interacts with the first surface 301 and the second surface 302 respectively; the second piezoelectric stacking mechanism 52 is disposed between the lower surface of the intermediate mass block 30 and the housing 10, and the second piezoelectric stacking mechanism 52 interacts with the lower surface of the intermediate mass block 30.

[0048] As a preferred embodiment, the first piezoelectric stacking mechanism 51 includes a first stacking block 511 and a second stacking block 512, the first stacking block 511 abuts against the first surface 301, and the second stacking block 512 abuts against the second surface 302.

[0049] The second piezoelectric stacking mechanism 52 includes a third stacking block 521, the third stacking block 521 is located between the lower surface of the intermediate mass block 30 and the housing 10 and abuts against the intermediate mass block 30. In detail, the number of the third stacking blocks 521 can be set to several.

[0050] Furthermore, the first piezoelectric stacking mechanism 51 further includes a first piezoelectric cover plate 513 and a second piezoelectric cover plate 514. Among them, the first piezoelectric cover plate 513 is assembled to the housing 10, and at the same time the first piezoelectric cover plate 513 is connected to the first stacking block 511, the second piezoelectric cover plate 514 is assembled to the housing 10, and the second piezoelectric cover plate 514 is connected to the second stacking block 512.

[0051] As a preferred embodiment, the first surface 301 is further provided with a first installation groove 3010, and the first stacking block 511 can be embedded in the first installation groove 3010 to achieve stable contact between the first stacking block 511 and the intermediate mass block 30; the second surface 302 is provided with a second installation groove 3020 to achieve stable contact between the second stacking block 512 and the intermediate mass block 30.

[0052] Since the piezoelectric stack block cannot withstand tangential forces, the piezoelectric actuating unit further includes a flexible decoupling mechanism, and flexible decoupling mechanisms are provided in all three XYZ phases (i.e., the horizontal and vertical directions). Specifically, the flexible decoupling mechanisms are disposed between the intermediate mass block 30 and the first piezoelectric stack mechanism 51, between the intermediate mass block 30 and the second piezoelectric stack mechanism 52, and between the intermediate mass block 30 and the pre-tightening mechanism 53.

[0053] The flexible decoupling mechanism includes a plurality of flexible gaskets. Preferably, the flexible gaskets are made of rubber gaskets. Of course, in some other embodiments, the flexible decoupling mechanism can also be made of other flexible materials.

[0054] As a preferred embodiment, the pre-tightening mechanism 53 includes a first pre-tightening component 530 and a second pre-tightening component 531. Taking the intermediate mass block 30 as a reference, the first pre-tightening component 530 is disposed on the opposite side of the first stack block 511, and the second pre-tightening component 531 is disposed on the opposite side of the second stack block 512.

[0055] In terms of details, the first pre-tightening component 530 includes a first elastic member 5301, a first fastener 5302, and a first pre-tightening cover plate 5303. One end of the first elastic member 5301 is connected to the intermediate mass block 30, the other end of the first elastic member is connected to the first fastener 5302, and the first fastener 5302 is connected to the housing 1 through the first pre-tightening cover plate 5303. Correspondingly, the second pre-tightening component 531 includes a second elastic member 5311, a second fastener 5312, and a second pre-tightening cover plate 5313. One end of the second elastic member 5311 is connected to the intermediate mass block 30, the other end of the second elastic member 5311 is connected to the second fastener 5312, and the second fastener 5312 is connected to the housing 10 through the second pre-tightening cover plate 5313.

[0056] Wherein, the first elastic member 5301 and the second elastic member 5311 include but are not limited to reed pieces, and the first fastener 5302 and the second fastener 5312 include but are not limited to bolts.

[0057] As a preferred embodiment, the decoupling mechanism includes a first gasket 541 disposed on the first stack block 511, a second gasket 542 disposed on the second stack block 512, a third gasket 543 disposed on the third stack block 521, a fourth gasket 544 disposed on the first pre-tightening component 530, and a fifth gasket 545 disposed on the second pre-tightening component 531. With this arrangement, decoupling can be achieved in the horizontal and vertical directions.

[0058] Further, the first sensor assembly includes a first sensor 21, a second sensor 22, and a third sensor 23. The first sensor 21 is used to monitor the movement of the carrying platform 20 in the first horizontal direction (X-axis direction), the second sensor 22 is used to monitor the movement of the carrying platform 20 in the Y-axis direction, and the third sensor 23 is used to monitor the movement of the carrying platform 20 in the vertical direction (Z-axis direction).

[0059] It should be noted that the first sensor 21, the second sensor 22, and the third sensor 23 include, but are not limited to, speed or acceleration sensors.

[0060] As a preferred implementation, the carrying platform 20 is provided with three independent blind hole structures for installing the first sensor assembly, so as to facilitate the assembly of the first sensor assembly on the carrying platform 20.

[0061] Furthermore, the second sensor assembly includes a fourth sensor 31, a fifth sensor 32, and a sixth sensor 33. The fourth sensor 31 is used to monitor the movement of the intermediate mass block 30 in the first horizontal direction (X-axis direction), the fifth sensor 32 is used to monitor the movement of the intermediate mass block 30 in the second horizontal direction (Y-axis direction), and the sixth sensor 33 is used to monitor the movement of the intermediate mass block 30 in the height direction (Z-axis direction).

[0062] The intermediate mass block 30 is provided with three independent blind hole structures for installing the second sensor assembly, so as to facilitate the assembly of the second sensor assembly on the intermediate mass block 30.

[0063] It should be noted that the fourth sensor 31, the fifth sensor 32, and the sixth sensor 33 include, but are not limited to, speed or acceleration sensors.

[0064] The passive vibration isolation unit includes a passive vibration isolation block 6, and the passive vibration isolation block 6 is made of an elastic material. The passive vibration isolation block 6 includes a first connection block 61 and a second connection block 62 connected to each other. The first connection block 61 is connected to the carrying platform 20, and the second connection block 62 is connected to the intermediate mass block 30. Moreover, the first connection block 61 and the second connection block 62 are symmetric to each other, and the cross-sectional shape of the first connection block 61 and the second connection block 62 in the height direction is trapezoidal. With such a setting, the vibration isolation effect of the passive vibration isolation block 6 can be improved, and its stability between the carrying platform 20 and the intermediate mass block 30 can be ensured.

[0065] In some other embodiments, the radial section of the passive vibration isolation block 6 is saddle-shaped.

[0066] As a preferred embodiment, the passive vibration isolation block 6 is of a rubber structure, or has metal plates on its upper and lower surfaces and a rubber material in the middle sandwich layer.

[0067] A plurality of mounting holes are formed in the side wall of the housing 10, and the pre-tightening mechanism 53, the first piezoelectric stack mechanism 51, and the second piezoelectric stack mechanism 52 are respectively assembled to the housing 10 through the mounting holes.

[0068] As a preferred embodiment, a third mounting groove 3030 is further provided on the third surface 303, and the first pre-tightening component 530 can be embedded in the third mounting groove 3030 to achieve stable contact between the first pre-tightening component 530 and the intermediate mass block 30; a fourth mounting groove 3040 is provided on the fourth surface 304, and the second pre-tightening component 531 can be embedded in the fourth mounting groove 3040 to achieve stable contact between the second pre-tightening component 531 and the intermediate mass block 30. Embodiment 2

[0069] The present invention also discloses a control system for a piezoelectric vibration isolator, in combination with Figures 9 to 11 As shown, the control system of the piezoelectric vibration isolator includes the piezoelectric vibration isolator as described in Embodiment 1; The control system of the piezoelectric vibration isolator further includes a signal output end; The control system of the piezoelectric vibration isolator further includes an outer loop control circuit, the outer loop control circuit includes an outer loop controller, the outer loop controller is connected to the first sensor assembly S1 of the load-bearing unit, and can output a first signal to the signal output end; The control system of the piezoelectric vibration isolator further includes an inner loop control circuit, the inner loop control circuit includes an inner loop controller, the inner loop controller is connected to the second sensor assembly S2 of the intermediate mass unit, and can output a second signal to the signal output end; The control system of the piezoelectric vibration isolator further includes a feedforward control circuit, the feedforward control circuit includes a feedforward controller, the feedforward controller is connected to the ground sensor S3, and can output a third signal to the signal output end; The outer loop control circuit is used to compensate the gain of the resonance frequency of the inner loop control circuit and improve the attenuation efficiency at the resonance frequency of the passive vibration isolator and the upper load. In addition, due to the hysteresis effect of the closed-loop feedback, after the ground vibration is output to the feedforward controller through the ground sensor S3, it is superimposed and output to the signal output end.

[0070] In specific applications, the vibration isolation effect is combined with Figure 10As shown, the piezoelectric vibration isolator adopting the above control architecture and structural form has a remarkable vibration isolation efficiency, with an attenuation effect of -40 dB below 500 Hz. In the low-frequency range below 10 Hz, the vibration isolation efficiency reaches -80 dB, which makes the piezoelectric active vibration damper of the present invention suitable for ultra-precision instruments.

[0071] Combined with Figure 11 As shown, the yellow color represents the ground vibration amplitude, and the blue color represents the load platform vibration amplitude.

[0072] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0073] In the present invention, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A piezoelectric vibration isolator, characterized in that: including, a housing unit, which includes a housing and an end cap, one end of the housing has an opening, and the end cap is detachably arranged at the opening; a bearing unit, which is arranged on the end cap, the bearing unit includes a bearing platform and a first sensor assembly, the first sensor assembly is installed on the bearing platform, and the bearing platform is used to bear a load; an intermediate mass unit, which is connected to the bearing platform, the intermediate mass unit is received in the housing, the intermediate mass unit includes an intermediate mass block and a second sensor assembly, and the second sensor assembly is installed on the intermediate mass block; a passive vibration isolation unit, which is arranged in the housing, the passive vibration isolation unit is connected to the bearing platform, and at the same time, the passive vibration isolation unit is also connected to the intermediate mass unit; a piezoelectric actuation unit, which is arranged in the housing, the piezoelectric actuation unit includes a first piezoelectric stack mechanism, a second piezoelectric stack mechanism and a preloading mechanism, the first piezoelectric stack mechanism can bear vibration in the horizontal direction, and the second piezoelectric stack mechanism can bear vibration in the height direction; the preloading mechanism is arranged opposite to the first piezoelectric stack mechanism, one end of the preloading mechanism is connected to the intermediate mass block, and the other end is connected to the housing, so that the first piezoelectric stack mechanism is kept in a compressed state; a controller unit, which is electrically connected to the bearing unit, the intermediate mass unit and the piezoelectric actuation unit, the controller unit can receive vibration signals, and after conversion, output electrical signals to the piezoelectric actuation unit; wherein, the piezoelectric actuation unit and the intermediate mass block form a high-frequency vibration system to isolate vibration within the control bandwidth; the passive vibration isolation unit and the load form a low-frequency vibration system to passively isolate vibration outside the bandwidth.

2. A piezoelectric vibration isolator according to claim 1, characterized in that: The intermediate mass block has a first surface, a second surface, a third surface and a fourth surface connected in sequence, and the first surface, the second surface, the third surface and the fourth surface form the side wall of the intermediate mass block; The first piezoelectric stack mechanism interacts with the first surface and the second surface respectively; the second piezoelectric stack mechanism is arranged between the lower surface of the intermediate mass block and the housing, and the second piezoelectric stack mechanism interacts with the lower surface of the intermediate mass block.

3. A piezoelectric vibration isolator according to claim 2, characterized in that: The first piezoelectric stack mechanism includes a first stack block and a second stack block, the first stack block abuts against the first surface, and the second stack block abuts against the second surface; The second piezoelectric stack mechanism includes a third stack block, and the third stack block abuts against the intermediate mass block.

4. A piezoelectric vibration isolator according to any one of claims 1-3, characterized in that: The piezoelectric actuation unit further includes a flexible decoupling mechanism, and the flexible decoupling mechanism is arranged between the intermediate mass block and the first piezoelectric stack mechanism, between the intermediate mass block and the second piezoelectric stack mechanism, and between the intermediate mass block and the preloading mechanism.

5. A piezoelectric vibration isolator according to claim 3, characterized in that: The pre-tightening mechanism includes a first pre-tightening component and a second pre-tightening component. The first pre-tightening component is disposed on the opposite side of the first stacking block, and the second pre-tightening component is disposed on the opposite side of the second stacking block. The first pre-tightening component includes a first elastic member and a first fastener, and the second pre-tightening component includes a second elastic member and a second fastener.

6. A piezoelectric vibration isolator according to claim 1, wherein: The first sensor assembly includes a first sensor, a second sensor, and a third sensor. The first sensor is used to monitor the movement of the carrying platform in the first horizontal direction, the second sensor is used to monitor the movement of the carrying platform in the second horizontal direction, and the third sensor is used to monitor the movement of the carrying platform in the height direction.

7. A piezoelectric vibration isolator according to claim 1, characterized in that: The second sensor assembly includes a fourth sensor, a fifth sensor, and a sixth sensor. The fourth sensor is used to monitor the movement of the intermediate mass block in the first horizontal direction, the fifth sensor is used to monitor the movement of the intermediate mass block in the second horizontal direction, and the sixth sensor is used to monitor the movement of the intermediate mass block in the height direction.

8. A piezoelectric vibration isolator according to claim 1, characterized in that: The passive vibration isolation unit includes a passive vibration isolation block made of an elastic material. The passive vibration isolation block includes a first connection block and a second connection block connected to each other. The first connection block is connected to the carrying platform, and the second connection block is connected to the intermediate mass block. The first connection block and the second connection block are symmetric to each other, and the cross-sections of the first connection block and the second connection block are trapezoidal.

9. A piezoelectric vibration isolator according to claim 1, characterized in that: A plurality of mounting holes are formed in the side wall of the housing, and the pre-tightening mechanism and the piezoelectric stacking mechanism are respectively assembled to the housing through the mounting holes.

10. A control system for a piezoelectric vibration isolator, characterized in that: including The piezoelectric vibration isolator according to any one of claims 1-9; Signal output terminal; An outer loop control circuit, which includes an outer loop controller. The outer loop controller is connected to the first sensor assembly of the carrying unit and can output a first signal to the signal output terminal; An inner loop control circuit, which includes an inner loop controller. The inner loop controller is connected to the second sensor assembly of the intermediate mass unit and can output a second signal to the signal output terminal; A feedforward control circuit, which includes a feedforward controller. The feedforward controller is connected to the ground sensor and can output a third signal to the signal output terminal; The outer loop control circuit is used to compensate the gain of the resonance frequency of the inner loop control circuit. After the ground vibration is output to the feedforward controller through the ground sensor, it is superimposed and output to the signal output terminal.

Images