CN202381623U - Precision active damper - Google Patents

Abstract

The utility model provides a precise active damping device with a compact structure, which belongs to the field of ultra-precision damping. The precision active damping device consists of a negative stiffness mechanism connected in parallel with an air spring to form a passive damping unit, and a Lorentz linear actuator to form an active damping unit. The negative stiffness mechanism is a compression rod structure composed of leaf springs, hinges and rigid rods. The negative stiffness mechanism is installed inside the cavity of the air spring, making the structure of the shock absorber more compact. The parallel connection of positive and negative stiffness makes the shock absorber have a large bearing capacity and extremely low stiffness, which greatly reduces its natural frequency. Lorentz linear actuators are used to provide active damping for active control. The precision active damping device provided by the utility model has an extremely low natural frequency, not only has a good vibration isolation effect on high-frequency vibration interference, but also can effectively isolate ultra-low frequency vibration, and is suitable for ultra-precision machining and vibration-sensitive measuring equipment.

Description

A precision active damping device

technical field

The utility model belongs to the field of ultra-precision vibration reduction, in particular to a precision active vibration reduction device. The precision active damping device involved in the utility model has an extremely low natural frequency, not only has a good vibration isolation effect on high-frequency vibration interference, but also can effectively isolate ultra-low-frequency vibration, and is suitable for ultra-precision machining sensitive to low-frequency vibration with measuring equipment. the

Background technique

With the development of science and technology, ultra-precision processing and measurement equipment represented by lithography machines, scanning tunneling microscopes (STM), scanning probe microscopes (SPM), and atomic force microscopes (AFM) have been more and more widely used. Due to its ultra-precision, this type of processing and measuring equipment has stricter requirements on environmental micro-vibration. The ultra-low-frequency precision active vibration reduction platform can effectively isolate the low-frequency micro-vibration of the foundation and the environment, and provide a stable working environment for the equipment. the

Common shock absorbers generally use helical steel springs, air springs and other components to isolate the vibration of the foundation. Helical steel springs cannot meet the requirements of large load capacity and low frequency vibration suppression at the same time. Although the air spring has a large bearing capacity and the ability to suppress low-frequency vibrations, if you want to achieve ultra-low-frequency vibration isolation, you must use methods such as increasing the volume of the air chamber, which will increase the volume of the shock absorber and make it difficult to control. Therefore, the natural frequency of a general air spring damper is usually around 1.5Hz-2Hz, and it is impossible to achieve ultra-low frequency vibration isolation below 1Hz. the

US Patent No. 5,844,664 provides an active damping device, the low stiffness in the vertical and horizontal directions is realized by an air spring and a yaw mechanism respectively. The vertical air spring adopts a diaphragm air spring. Due to the limitation of the volume of the shock absorber and the requirements on control, it is impossible to achieve ultra-low frequency vibration isolation. the

The patent document WO95/20113 published by the World Organization WIPO provides an ultra-low frequency passive shock absorber with positive and negative stiffness in parallel. A mechanism whose preload can be adjusted by screws. In order to support the changing load, the screw adjustment mechanism is used to adjust the position of the vertical support spring so that the vertical negative stiffness mechanism always works near the equilibrium position. the

Contents of the invention

The purpose of this utility model is to provide a precision active damping device, which has a compact structure and a very low natural frequency, not only has a good vibration isolation effect on high-frequency vibration interference, but also can effectively isolate the foundation and the environment Ultra-low frequency vibration provides a stable working environment for ultra-precision processing and measuring equipment. the

The utility model provides a precision active damping device, which is characterized in that the damping device includes an active damping unit and a passive damping unit, and the active damping unit and the passive damping unit are connected in parallel; the active damping unit includes a Loren For the linear actuator, the passive damping unit is composed of a negative stiffness mechanism and an air spring connected in parallel, and the negative stiffness mechanism is installed inside the chamber of the air spring;

The air spring includes a metal chamber, a rubber film, a metal pressure ring, a mounting seat, a load bearing plate, a limit device, an upper piston plate, a lower piston plate and an air inlet; The cylindrical structure, the upper piston plate and the lower piston plate are located inside the metal chamber, and are flexibly connected to the metal chamber through the rubber film; the rubber film is in a ring structure, and the inner ring of the rubber film is placed between the upper piston plate and the lower piston plate, and Lock and seal to form the piston structure of the air spring; the metal pressure ring presses the outer ring of the rubber film on the metal chamber, and after installing the mounting seat on it, the metal pressure ring and the rubber film are pressed and connected to the metal chamber; The position device is installed on the mounting base, and the load bearing plate is fixedly connected with the upper piston plate to support the load of the shock absorber; the air intake hole is used to communicate with the air supply system;

Negative stiffness mechanism includes vertical support piston rod, first and second compression rods, first and second leaf springs, first and second clamping blocks, third and fourth clamping blocks, first and second adjustment block, first and second adjustment guide rods, reinforcement beams and bottom plate;

The bottom plate is fixedly installed at the bottom of the metal chamber, the vertical support piston rod is fixedly connected with the lower piston plate, the vertical support piston rod is connected with one end of the first pressure rod and the second pressure rod through a hinge, and the other end of the first pressure rod It is connected to the first clamping block through a hinge, and the other end of the second pressure rod is connected to the second clamping block through a hinge; the first piece of spring passes through the first adjustment block, and the two ends of the first piece of spring respectively pass through the first The clamping block and the third clamping block are clamped; the first piece of spring passes through the second adjustment block, and the two ends of the second piece of spring are respectively clamped by the second clamping block and the fourth clamping block; the clamping block It is fixedly connected with the bottom plate, and then the plate spring is fixed, the adjustment guide rod passes through the first adjustment block, and its bottom end is fixedly connected with the bottom plate, the adjustment guide rod passes through the adjustment block, and its bottom end is fixedly connected with the bottom plate, the first and second adjustments The top ends of the guide rods are fixedly connected with the reinforcement beam; the adjustment block is fixed on the adjustment guide rod;

The active damping unit also includes a vibration velocity sensor and an eddy current displacement sensor; the Lorentz linear actuator includes a Lorentz linear actuator mover and a stator; the mover is fixedly connected to the load bearing plate, and the stator is installed on the mounting base The vibration velocity sensor and the eddy current displacement sensor are used for vibration feedback control of the shock absorber, and the vibration velocity sensor is installed on the load support plate; the eddy current displacement sensor is installed on the mounting base. the

The negative stiffness mechanism included in the shock absorber of the utility model has an adjustable negative stiffness, which is used to match the positive stiffness of the air spring, thereby adjusting the stiffness of the shock absorber. The adjustment of the negative stiffness is realized by adjusting the effective bending length of the leaf spring; in addition, two or more leaf springs can be superimposed in parallel to adjust the stiffness of the negative stiffness mechanism. the

The precision active damping device provided by the utility model is composed of a negative stiffness mechanism, a passive damping part composed of an air spring, and an active actuator Lorentz linear actuator connected in parallel. While isolating high-frequency vibrations, it can also effectively isolate Vertical ultra-low frequency vibration overcomes the shortcoming that ordinary shock absorbers cannot achieve ultra-low frequency vibration isolation, and is suitable for ultra-precision processing and measuring equipment that is sensitive to low-frequency vibration. Specifically, the utility model has the following technical characteristics:

(1) Adopting the method of parallel connection of positive and negative stiffness, the shock absorber has an extremely low natural frequency, which not only has a good vibration isolation effect on high-frequency vibration interference, but also effectively isolates ultra-low frequency vibration;

(2) The parallel connection of active actuators and passive damping components can effectively increase the damping of the shock absorber and achieve good vibration transfer characteristics near the natural frequency;

(3) The active actuator adopts the Lorentz linear actuator, which can not only realize active vibration reduction, but also act as a vibration exciter to excite the vibration reduction system, and then perform parameter identification on the vibration reduction system;

(4) The negative stiffness mechanism is installed inside the cavity of the air spring, and the structure is more compact;

(5) The bending stiffness of the leaf spring can be adjusted by adjusting the bending length of the leaf spring, and then the vertical negative stiffness of the negative stiffness mechanism can be adjusted under the condition of constant deformation. the

Description of drawings

Fig. 1 is the structural representation of precision active damping device provided by the utility model;

Fig. 2 is the structural representation of the utility model negative stiffness mechanism;

Fig. 3 is the schematic diagram of the positive and negative stiffness parallel connection of the shock absorber provided by the utility model;

Fig. 4 is the schematic diagram of the utility model negative stiffness mechanism;

Fig. 5 is the stiffness curve of the negative stiffness mechanism of the present invention. the

Detailed ways

The structure and working principle of the specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. the

As shown in Figure 1, the precision active damping device provided by the utility model includes a passive damping unit and an active damping unit with positive and negative stiffnesses connected in parallel, and the passive damping unit and the active damping unit are connected in parallel. the

The passive damping unit consists of a positive stiffness air spring connected in parallel with a negative stiffness mechanism. The positive stiffness air spring includes a metal chamber 1, a rubber membrane 2, a metal pressure ring 3, a mounting seat 4, a load support plate 5, a limit device 6, an upper piston plate 8, a lower piston plate 9 and an air inlet 14. The metal chamber 1 is a cylindrical structure with a hollow interior and an open upper end. When in use, the periphery of the bottom plate is connected with the foundation through screws. The upper piston plate 8 and the lower piston plate 9 are located inside the metal chamber 1 and flexibly connected with the metal chamber 1 through the rubber membrane 2 . The rubber membrane 2 has a ring structure, and the inner ring of the rubber membrane 2 is placed between the upper piston plate 8 and the lower piston plate 9, and is locked and sealed with screws 10 distributed around the circumference to form a piston structure of an air spring. The metal pressure ring 3 presses the outer ring of the rubber film 2 on the metal chamber 1, and the metal pressure ring 3 and the rubber film 2 are pressed and connected to the metal chamber 1 by the screws distributed around the top after installing the mounting seat 4 on it. The mounting base 4 serves as an auxiliary installation for installing the limit device 6 , the stator 12 of the Lorentz linear actuator and the eddy current displacement sensor 13 . The limit device 6 is used for safety protection, limits the vertical vibration amplitude of the shock absorber load, and can also lock the shock absorber during transportation to prevent the load support plate 5 from vibrating up and down. The load support plate 5 is fixedly connected with the upper piston plate 8 by screws for supporting the load of the shock absorber. The air intake hole 14 communicates with the air supply system, and the compressed air generated by the air supply system enters the air spring chamber through the air intake hole 14 to float the load. the

The negative stiffness mechanism is a negative stiffness structure of the pressure rod, which is placed inside the cavity of the air spring. As shown in Figure 1 and Figure 2, the negative stiffness mechanism is a symmetrical compression rod structure, which includes a vertical support piston rod 15, first and second compression rods 16a and 16b, first and second leaf springs 18a and 18b , first and second clamping blocks 19a and 19b, third and fourth clamping blocks 17a and 17b, first and second adjustment blocks 20a and 20b, first and second adjustment guide rods 21a and 21b, reinforcement beams 22 and base plate 23. the

The bottom plate 23 is fixedly installed on the bottom of the metal chamber 1 . The installation of the negative stiffness mechanism must ensure that the axis line of the vertical support piston rod 15 coincides with the axis line of the metal chamber wall 1 . The vertical support piston rod 15 is fixedly connected with the lower piston plate 9 by screws. The vertical support piston rod 15 is connected to one end of the compression rod 16a, 16b through a hinge, the other end of the compression rod 16a is connected to the clamping block 17a through a hinge, and the other end of the compression rod 16b is connected to the clamping block 17b through a hinge. The leaf spring 18a passes through the first adjustment block 20a, and the two ends of the leaf spring 18a are respectively clamped by the clamping block 19a and the clamping block 17a; the leaf spring 18b passes through the second adjustment block 20b, and the two ends of the leaf spring 18b Clamped by clamping block 19b and clamping block 17b respectively. The clamping blocks 19a, 19b are fixedly connected to the bottom plate 23, thereby fixing the leaf springs 18a, 18b. The adjustment guide rod 21a passes through the first adjustment block 20a, and its bottom end is fixedly connected with the base plate 23; the adjustment guide rod 21b passes through the adjustment block 20b, and its bottom end is fixedly connected with the base plate 23; The reinforcing beam 22 is fixedly connected. The structure composed of adjustment blocks 20a, 20b and adjustment guide rods 21a, 21b is used to adjust the bending stiffness of the leaf springs 18a, 18b, thereby adjusting the vertical negative stiffness of the negative stiffness mechanism to match the stiffness of the positive stiffness air spring. The principle is to adjust the bending stiffness of the leaf springs 18a, 18b by adjusting their effective bending lengths. In addition, two or more leaf springs can be stacked in parallel to increase the bending stiffness. The adjustment blocks 20a, 20b are fixed on the adjustment guide rods 21a, 21b by set screws. The reinforcing beam 22 plays an auxiliary role for enhancing the bending rigidity of the adjustment guide rods 21a, 21b. the

The active damping unit includes a Lorentz linear actuator, a vibration velocity sensor 7 and an eddy current displacement sensor 13 . The Lorentz linear actuator includes a Lorentz linear actuator mover 11 and a stator 12 . The mover 11 is fixedly connected with the load bearing plate 5 , and the stator 12 is installed on the mounting seat 4 . The mover 11 is a permanent magnet, and the stator 12 is a coil. The vibration velocity sensor 7 and the eddy current displacement sensor 13 are used for the vibration feedback control of the shock absorber. The vibration velocity sensor 7 is installed on the load bearing plate 5, and feedbacks back to the absolute velocity of the load. The Lorentz linear actuator is used for the vibration feedback control through the feedback control algorithm. Loads apply forces for active vibration control. The eddy current displacement sensor 13 is installed on the mount 4 . The eddy current displacement sensor 13 can also be used for positioning control of the load in addition to being used for vibration feedback control. the

Fig. 3 is a principle diagram of parallel connection of positive and negative stiffnesses of the shock absorber of the present invention. The vertical positive stiffness _Ka is provided by the air spring, and the pressure rods 16a, 16b will be in an unstable state under the pre-tightening pressure of the leaf springs 18a, 18b at the equilibrium position. When there is an external disturbance acting on the center hinge, the center hinge is relatively When the equilibrium position deviates, the pre-tightening pressure received by the compression rods 16a, 16b will promote the increase of the offset at the central hinge, thereby forming a vertical negative stiffness.

Figure 4 shows the principle of the formation of the negative stiffness of the compression rod. The bending stiffness of the leaf springs 18a, 18b is _Kw , the length of the compression rods 16a, 16b is L, and the initial bending deformation of the leaf springs 18a, 18b at the equilibrium position is δ when there is no external disturbance. When there is an external disturbance, the center hinge will be offset by x in the vertical direction, and an external force F _n is needed to balance it. The expression of F _n is shown in formula (1):

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; -</span>\sqrt{{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&CenterDot;</span>\frac{\mathrm{<span\; class="notranslate">\; x</span>}}{\sqrt{{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Then the expression of the stiffness K _n formed by the mechanism is:

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}}{\mathrm{<span\; class="notranslate">\; dx</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; )</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Fig. 5 is the stiffness curve of the negative stiffness mechanism of the present invention according to formula (2), wherein the initial deformation δ of the given leaf springs 18a, 18b is 10mm, and the length L of the compression rods 16a, 16b is 50mm. In Fig. 5, the abscissa represents the offset x of the central hinge relative to the equilibrium position, and the ordinate represents the stiffness coefficient of the compression bar mechanism (ie K _n /2K _w ). It can be seen from Figure 5 that when the offset x at the center hinge exceeds a certain value x ₀ , the stiffness of the mechanism becomes positive. Let formula (2) be equal to zero to obtain the expression of x ₀ as:

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; \&PlusMinus;</span>\sqrt{{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; 3</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 3</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In order to ensure that the compression bar mechanism forms a negative stiffness, it is necessary for the load to work near the equilibrium position. In an ultra-precision shock absorber, the vibration amplitude of the load is usually at the micron level, so x<<L, at this time, according to formula (2), the stiffness of the compression rod mechanism can be expressed as:

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

After the shock absorber floats the load, adjust the vertical position of the shock absorber load so that the negative stiffness mechanism is at or near the equilibrium position shown in Figure 3. Under the slight vibration of the load, the stiffness of the negative stiffness mechanism can be given by formula (4). the

The above description is only a preferred embodiment of the utility model, but the utility model should not be limited to the content disclosed in the embodiment and accompanying drawings. Therefore, all equivalents or modifications that do not deviate from the spirit disclosed by the utility model fall within the protection scope of the utility model. the

Claims (1)

1. A precision active damping device, characterized in that, the damping device comprises an active damping unit and a passive damping unit, and the active damping unit and the passive damping unit are connected in parallel; the active damping unit comprises a Lorentz linear actuator The actuator, the passive damping unit is composed of a negative stiffness mechanism and an air spring connected in parallel, and the negative stiffness mechanism is installed inside the chamber of the air spring; The air spring includes a metal chamber, a rubber film, a metal pressure ring, a mounting seat, a load bearing plate, a limit device, an upper piston plate, a lower piston plate and an air inlet; The cylindrical structure, the upper piston plate and the lower piston plate are located inside the metal chamber, and are flexibly connected to the metal chamber through the rubber film; the rubber film is in a ring structure, and the inner ring of the rubber film is placed between the upper piston plate and the lower piston plate, and Lock and seal to form the piston structure of the air spring; the metal pressure ring presses the outer ring of the rubber film on the metal chamber, and after installing the mounting seat on it, the metal pressure ring and the rubber film are pressed and connected to the metal chamber; The position device is installed on the mounting base, and the load support plate is fixedly connected with the upper piston plate to support the load of the shock absorber; the air intake hole is used to communicate with the air supply system; Negative stiffness mechanism includes vertical support piston rod, first and second compression rods, first and second leaf springs, first and second clamping blocks, third and fourth clamping blocks, first and second adjustment block, first and second adjustment guide rods, reinforcement beams and bottom plate; The bottom plate is fixedly installed at the bottom of the metal chamber, the vertical support piston rod is fixedly connected with the lower piston plate, the vertical support piston rod is connected with one end of the first pressure rod and the second pressure rod through a hinge, and the other end of the first pressure rod It is connected to the first clamping block through a hinge, and the other end of the second pressure rod is connected to the second clamping block through a hinge; the first piece of spring passes through the first adjustment block, and the two ends of the first piece of spring respectively pass through the first The clamping block and the third clamping block are clamped; the first piece of spring passes through the second adjustment block, and the two ends of the second piece of spring are respectively clamped by the second clamping block and the fourth clamping block; the clamping block It is fixedly connected with the bottom plate, and then the plate spring is fixed, the adjustment guide rod passes through the first adjustment block, and its bottom end is fixedly connected with the bottom plate, the adjustment guide rod passes through the adjustment block, and its bottom end is fixedly connected with the bottom plate, the first and second adjustments The top ends of the guide rods are fixedly connected with the reinforcement beam; the adjustment block is fixed on the adjustment guide rod; The active damping unit also includes a vibration velocity sensor and an eddy current displacement sensor; the Lorentz linear actuator includes a Lorentz linear actuator mover and a stator; the mover is fixedly connected to the load bearing plate, and the stator is installed on the mounting base The vibration velocity sensor and the eddy current displacement sensor are used for vibration feedback control of the shock absorber, and the vibration velocity sensor is installed on the load support plate; the eddy current displacement sensor is installed on the mounting base. the

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