Control method for a variable air spring volume vibration isolation device with adjustable stiffness

Abstract

The application discloses a control method of a stiffness-adjustable variable air spring volume vibration isolation device, which comprises the following steps: fixing the stiffness-adjustable variable air spring volume vibration isolation device and a vibration table through a top plate (21) on the vibration isolation device; assembling a displacement sensor on the vibration isolation device, connecting a hydraulic system and a pressure sensor (25) of the vibration isolation device with a controller B and a position-pressure conversion device, and connecting the displacement sensor, the controller B and the position-pressure conversion device with a controller A; and realizing closed-loop control of the position of the vibration table, the position of the vibration isolation device and the pressure of an additional air chamber by using the controller, the displacement sensor and the hydraulic system, so that the positioning accuracy of the vibration table and the stiffness of the air spring can be better controlled.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vibration isolation devices, in particular to a control method of a variable air spring volume vibration isolation device with adjustable stiffness. BACKGROUND

[0002] At present, most of the shock absorption methods of the vibration table are to combine two or more groups of air springs, and to satisfy the vibration of multiple directions of the vibration table through the combination of multiple groups of shock absorption devices. This results in the imbalance of the shock absorption device and the multi-directional shock absorption effect. It also occupies more experimental space and costs more funds in the overall structure. On the other hand, it is well known that the volume of the air spring has a significant effect on its stiffness characteristics. As the air chamber volume of the air spring increases, the stiffness of the air spring decreases; if the air chamber volume of the air spring decreases, the stiffness of the air spring increases.

[0003] In the current air spring shock absorption device, most of them are pure mechanical vibration isolation, which results in the stiffness of the shock absorption device being unchangeable. Different measured objects need to be measured by the vibration table, and the weights and volumes of different measured objects are different. The measured objects need to be positioned on the same horizontal line at the beginning, so a stiffness-adjustable shock absorption device is needed to meet the requirements. At the same time, the stiffness-adjustable shock absorption device acting on the vibration table is not easy to achieve precise positioning control by pure mechanical structure due to the different weights and loads of the measured objects, so there is an urgent need for a device and a control method that can meet the above requirements. SUMMARY

[0004] In view of the above technical deficiencies, the purpose of the present application is to provide a control method of a variable air spring volume vibration isolation device with adjustable stiffness.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] The present application provides a variable air spring volume vibration isolation device with adjustable stiffness, which comprises a vibration isolation device base for fixing with the foundation, a flared quadrangular pyramid structure is formed on the upper part of the vibration isolation device base, four groups of volume-adjustable air springs are uniformly arranged on the four inner sides of the flared quadrangular pyramid structure, the flared quadrangular pyramid structure is fixed with a vibration isolation device upper top plate with a quadrangular pyramid side surface through the air springs, an additional air chamber for adjusting the stiffness of the air spring is formed in the vibration isolation device upper top plate, the bottom of the additional air chamber is in communication with the four groups of air springs, the top of the additional air chamber is in communication with a hydraulic system for injecting water into the additional air chamber for pressurization, and an additional air chamber support frame for fixing the additional air chamber is formed on the vibration isolation device upper top plate.

[0007] Preferably, the air spring is arranged at an angle of 45 degrees with the horizontal bottom surface of the vibration isolation device base.

[0008] Preferably, the inclination angle and direction of the quadrangular frustum side of the upper top plate of the vibration isolation device is the same as that of the flared quadrangular frustum structure.

[0009] Preferably, the upper top plate of the vibration isolation device is internally formed with a communication pipeline communicating the four sets of air springs and the bottom of the additional air chamber.

[0010] Preferably, the additional air chamber is coaxially arranged with the vibration isolation device base.

[0011] Preferably, the additional air chamber comprises an additional air chamber base, an upper sealing top plate is fixed on the upper portion of the additional air chamber base, an additional air cabin is formed between the upper sealing top plate and the additional air chamber base, an elastic air bag is fixed on the upper portion of the additional air chamber base, the elastic air bag divides the additional air cabin into a water injection chamber for communicating with the hydraulic system and a pressurized chamber for communicating with the four air springs, and a pressure sensor two is installed on the inner side wall of the additional air chamber base corresponding to the pressurized chamber.

[0012] Preferably, a sealing rubber ring is installed at the connection between the upper sealing top plate and the additional air chamber base.

[0013] Preferably, the hydraulic system comprises an oil tank, a filter, a high-pressure ball valve, a variable pump, a driving motor, a one-way valve, a safety valve, a pressure reducing valve, a pressure sensor one, an accumulator, an oil temperature gauge, a servo valve, a servo hydraulic cylinder, a water injection device, a water injection pipeline, and a stop valve, the driving motor is used to drive the variable pump, the oil inlet of the variable pump is communicated with the oil tank through the high-pressure ball valve and the filter in sequence, the oil outlet of the variable pump is communicated with the oil inlet of the one-way valve, the oil outlet of the one-way valve is divided into two paths, one path is communicated with the oil tank through the safety valve, and the other path is communicated with the oil inlet of the servo hydraulic cylinder through the pressure reducing valve and the servo valve in sequence, the oil return port of the servo hydraulic cylinder is communicated with the oil tank through the servo valve, the piston rod of the servo hydraulic cylinder is fixed with the piston rod of the water injection device, the water outlet of the water injection device is connected with the water inlet of the stop valve through the water injection pipeline, the water outlet of the stop valve is communicated with the additional air chamber, the oil inlet of the pressure reducing valve is further connected with the accumulator, the pressure sensor one is installed on the pipeline communicated with the pressure reducing valve, and the oil temperature gauge is installed on the pipeline communicated with the servo valve.

[0014] The application further provides a control method of the above device, comprising the following steps:

[0015] (1) fixing the device and the vibration table through the upper top plate of the vibration isolation device; assembling a displacement sensor on the vibration isolation device, which is used to detect the displacement parameters of the vibration table; connecting the hydraulic system and the pressure sensor two of the vibration isolation device with the controller B and the position-pressure conversion device; connecting the displacement sensor, the controller B, and the position-pressure conversion device with the controller A;

[0016] (2) the initial position information parameters of the required vibration table are input into the controller A, then the position distance signal of the vibration table detected by the displacement sensor at this time is subtracted from the input position signal to obtain a difference value position signal, the difference value position signal is input into the position-pressure conversion device to obtain a pressure signal, the converted pressure signal is subtracted from the pressure signal fed back by the pressure sensor two of the additional air chamber to obtain the gap between the expected pressure and the actual pressure, then the difference value is input into the controller B, the pressure control signal is given through the difference value, the pressure control signal is input into the pressure-displacement conversion device, and the pressure difference value signal is converted into a displacement position signal through the device; at the same time, the controller B outputs the converted displacement position signal to the servo valve, and the servo valve adjusts the working position of the servo hydraulic cylinder according to the difference value after obtaining the signal, the displacement of the servo hydraulic cylinder piston rod drives the displacement of the piston rod of the water injection device, and then the elastic air bag of the additional air chamber is pressurized or depressurized, so that the internal pressure changes, and the pressure sensor two in the pressurized chamber collects the pressure change and simultaneously feeds back the pressure change parameter to the controller B, and the controller B subtracts the pressure fed back by the pressure sensor two from the pressure parameter converted by the position-pressure conversion device until the pressures are equal;

[0017] (3) when the vibration table is subjected to external force and position deviation occurs, the relevant displacement parameter signal of the relevant vibration table is detected by the displacement sensor, and the adjustment is carried out in the mode of the steps to realize the closed-loop control of the position of the vibration table, the position of the vibration isolation device and the pressure of the additional air chamber.

[0018] The beneficial effects of the present application are as follows:

[0019] The device of the present application adopts the variable-volume air spring, which can overcome the problems of single vibration isolation effect of the traditional vibration isolation device and poor vibration isolation effect under different loads.

[0020] The four variable-volume air springs are arranged at different directions of 45 degrees with the ground, and the four air springs work cooperatively to achieve the multi-directional damping effect. In addition, the stiffness of the air spring damping device after loading changes with the volume of the air spring, and the stiffness of the air spring can be adjusted through the feedback value of the sensor to meet the expected vibration isolation effect under different loads, different vibration amplitudes and different vibration frequencies.

[0021] The method of the present application is simple to operate and can realize the closed-loop control of the position of the vibration table, the position of the vibration isolation device and the pressure of the additional air chamber to more accurately meet the positioning accuracy control of the vibration table. BRIEF DESCRIPTION OF DRAWINGS

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 Here is a structural diagram of the vibration isolation device according to an embodiment of the present invention:

[0024] Figure 2 This is a cross-sectional schematic diagram of the vibration isolation device according to an embodiment of the present invention:

[0025] Figure 3 The hydraulic system of this embodiment is shown in the figure.

[0026] Figure 4 This is a schematic diagram of the structure of the additional air chamber in an embodiment of the invention;

[0027] Figure 5 This is a schematic diagram of the control method of the present invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Oil tank; 2. Filter; 3. High-pressure ball valve; 4. Variable pump; 5. Drive motor; 6. Check valve; 7. Safety valve; 8. Pressure reducing valve; 9. Pressure sensor one; 10. Accumulator; 11. Oil temperature gauge; 12. Servo valve; 13. Servo hydraulic cylinder; 14. Water injection device; 15. Water injection pipeline; 16. Shut-off valve; 18. Vibration isolation device base; 19. Air spring; 20. Additional air chamber support frame; 21. Vibration isolation device top plate; 22. Additional air chamber; 23. Additional air chamber base; 24. Elastic airbag; 25. Pressure sensor two; 26. Sealing rubber ring; 27. Upper sealing top plate; 28. Connecting pipe. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figures 1 to 5 As shown in the figure, this embodiment provides a variable air spring volume vibration isolation device with adjustable stiffness and its control method.

[0032] The adjustable stiffness variable air spring volume vibration isolation device comprises a vibration isolation device base 18 for fixing with the ground foundation, the upper part of the vibration isolation device base 18 is formed with a flared quadrangular pyramid structure, four groups of volume adjustable air springs 19 are uniformly arranged on the four inner sides of the flared quadrangular pyramid structure, the flared quadrangular pyramid structure is fixed with a vibration isolation device upper top plate 21 with a quadrangular pyramid shaped side surface through the air springs 19, an additional air chamber 22 for adjusting the stiffness of the air springs 19 is formed in the vibration isolation device upper top plate 21, the bottom of the additional air chamber 22 is communicated with the four groups of air springs 19, the top of the additional air chamber 22 is communicated with a hydraulic system for injecting water and pressurizing the additional air chamber 22, the top of the additional air chamber 22 is communicated with a hydraulic system for injecting water and pressurizing the additional air chamber 22, an additional air chamber support frame 20 for fixing the additional air chamber 22 is formed on the vibration isolation device upper top plate 21.

[0033] The air springs 19 are arranged at an angle of 45 degrees with the horizontal bottom surface of the vibration isolation device base 18. The inclination angle and direction of the quadrangular pyramid shaped side surface of the vibration isolation device upper top plate 21 are the same as those of the flared quadrangular pyramid structure. The vibration isolation device upper top plate 21 is formed with a communication pipeline 28 communicating the four groups of air springs 19 and the bottom of the additional air chamber 22. The additional air chamber 22 is arranged coaxially with the vibration isolation device base 18. The additional air chamber 22 comprises an additional air chamber base 23, an upper sealing top plate 27 is fixed on the upper part of the additional air chamber base 23, an additional air chamber is formed between the upper sealing top plate 27 and the additional air chamber base 23, an elastic air bag 24 is fixed on the upper part of the additional air chamber base 23, the elastic air bag 24 divides the additional air chamber into a water injection chamber for communicating with the hydraulic system and a pressurized chamber for communicating with the four air springs, a pressure sensor two 25 is installed on the inner side wall of the additional air chamber base 23 corresponding to the pressurized chamber. A sealing rubber ring 26 is installed at the connection between the upper sealing top plate 27 and the additional air chamber base 23.

[0034] The hydraulic system comprises an oil tank 1, a filter 2, a high-pressure ball valve 3, a variable pump 4, a driving motor 5, a check valve 6, a safety valve 7, a pressure reducing valve 8, a pressure sensor 9, an accumulator 10, an oil temperature gauge 11, a servo valve 12, a servo hydraulic cylinder 13, a water injection device 14, a water injection pipeline 15, a stop valve 16, the driving motor 5 is used for driving the variable pump 4, an oil inlet of the variable pump 4 is communicated with the oil tank 1 in sequence through the high-pressure ball valve 3 and the filter 2, an oil outlet of the variable pump 4 is communicated with an oil inlet of the check valve 6, an oil outlet of the check valve 6 is divided into two paths, one path is communicated with the oil tank 1 through the safety valve 7, and the other path is communicated with an oil inlet of the servo hydraulic cylinder 13 in sequence through the pressure reducing valve 8 and the servo valve 12, an oil return port of the servo hydraulic cylinder 13 is communicated with the oil tank 1 through the servo valve 12, a piston rod of the servo hydraulic cylinder 13 is fixed with a piston rod of the water injection device 14, an outlet of the water injection device 14 is connected with an inlet of the stop valve 16 through the water injection pipeline 15, an outlet of the stop valve 16 is communicated with an additional air chamber 22, the accumulator 10 is further connected with the oil inlet of the pressure reducing valve 8, the pressure sensor 9 is installed on a pipeline communicated with the pressure reducing valve 8, and the oil temperature gauge 11 is installed on a pipeline communicated with the servo valve 12.

[0035] The working principle of the hydraulic system is as follows: the driving motor 5 provides power for the variable pump 4, the variable pump 4 provides power oil for the whole hydraulic system, drives the hydraulic oil to be input into the hydraulic system from the oil tank 1, the hydraulic oil is filtered through the filter 2 and the high-pressure ball valve 3, and then is delivered to the check valve 6, the check valve 6 ensures that the hydraulic oil cannot flow back, and the safety valve 7 ensures that the working pressure of the whole system does not exceed pressure, the pressure reducing valve 8 is used for keeping the pressure oil as a specific pressure, the pressure sensor 9 displays real-time oil pressure, and alarms in time when an error occurs, the accumulator 10 is used as an energy storage device, and ensures that the system normally works, the servo valve 12 works at the left position or the right position, so that the servo hydraulic cylinder 13 can be extended or retracted leftward and rightward, and then drives the water injection device 14 to inject water into the elastic air bag 24 in the additional air chamber, and the stop valve 16 is used for closing the stop valve 16 after the water injection is completed and the air spring reaches a stable position, so that the water injection device is stably kept at a position under the condition that the servo hydraulic cylinder 13 does not need to continuously work, the size of the air bag of the additional air chamber is kept unchanged, the air spring rigidity is kept stable, and the expected effect is achieved.

[0036] The embodiment further provides a control method of the device, and specifically comprises the following steps.

[0037] (1) The device is fixed to the vibration table by the top plate 21 of the vibration isolation device; a displacement sensor is installed on the vibration isolation device to detect the displacement parameters of the vibration table; the installation position of the displacement sensor is determined by the existing installation method known to those skilled in the art, which will not be described in detail; the hydraulic system of the vibration isolation device, the pressure sensor 25, and the controller B are connected to the position-pressure conversion device; the displacement sensor, the controller B, and the position-pressure conversion device are connected to the controller A;

[0038] (2) The initial position information parameters of the required vibration table are input into the controller A, then the position distance signal of the vibration table detected by the displacement sensor at this time is subtracted from the input position signal to obtain a difference value position signal, the difference value position signal is input into the position-pressure conversion device to obtain a pressure signal; the converted pressure signal is subtracted from the pressure signal fed back by the pressure sensor 25 of the additional air chamber 22 to obtain the difference between the expected pressure and the actual pressure, then the difference is input into the controller B, the pressure control signal is given by the difference, the pressure control signal is input into the pressure-displacement conversion device, the pressure difference signal is converted into a displacement position signal by the device; at the same time, the controller B outputs the converted displacement position signal to the servo valve 12, after the servo valve 12 receives the signal, the working position of the servo hydraulic cylinder 13 is adjusted according to the difference, the displacement of the servo hydraulic cylinder 13 piston rod drives the displacement of the piston rod of the water injection device 14, and then the elastic air bag 24 of the additional air chamber 22 is pressurized or depressurized, causing the internal pressure to change, the pressure sensor 25 in the pressurized chamber collects the pressure change and simultaneously feeds back the pressure change parameters to the controller B, the controller B subtracts the pressure fed back by the pressure sensor 25 from the pressure parameters converted by the position-pressure conversion device until the pressures are equal;

[0039] The working principle of the additional air chamber 22 is as follows: water is injected into the water injection chamber of the additional air chamber 22 through the water injection device 14. The space between the elastic air bag 24 and the upper sealing top plate 27 is increased through the injection of water. Due to the extensibility and elasticity of the elastic air bag 24, the space between the lower part of the elastic air bag 24 and the additional air chamber base 23 is reduced, that is, the pressurized chamber is reduced, the gas in the pressurized chamber is compressed, and the gas is injected into the four air springs 19 in groups through the communication pipeline 28 below the additional air chamber 22, so as to achieve the effect of adjusting the pressure in the pressurized chamber and the stiffness of the air spring. The pressure sensor two 25 is used to measure the pressure in the air spring 19 and the pressurized chamber, and feed back the measured information to the system. If the pressure is too high, the vibration table deviates from the predetermined position or the stiffness of the air spring stiffness does not meet the requirements, the power source and the servo hydraulic cylinder are adjusted through the feedback data, the hydraulic cylinder is retracted, the water injection device is retracted, the volume of the elastic air bag is reduced, the pressure in the air spring and the pipeline is reduced, and the adjustment purpose is achieved. If the pressure is too low, the process is opposite to the above process. Through the feedback of the pressure sensor and then the adjustment, the internal pressure and the overall final position achieve the expected effect.

[0040] (3) When the vibration table is deviated due to external force, the displacement sensor detects the relevant displacement parameter signal of the relevant vibration table, adjusts in the manner of step (2), and realizes the closed-loop control of the position of the vibration table, the position of the vibration isolation device, and the pressure of the additional air chamber.

[0041] Due to the change of the additional air chamber, the internal pressure changes, so the internal pressure of the air spring changes, and the internal stiffness and initial position of the air spring also change, which causes the displacement of the vibration isolation device in the vertical direction. The displacement sensor mounted on the vibration isolation device measures the displacement parameter of the vibration table, and the displacement parameter is subtracted from the position signal sent by the controller, and then the parameter obtained by the subtraction is input into the control system, and the difference value is input into the controller A. At this point, a displacement closed-loop system is established. Since the vibration table is supported by the vibration isolation device, the position of the vibration table is determined by the vibration isolation device, so the loading plane of the vibration table also changes in position. At the same time, since the vibration table plane needs to load the measured object, the position of the vibration table plane will also have a great influence, so the external interference is introduced here. The displacement sensor measures the position change of the vibration table plane under the influence of these factors, and feeds back the actual adjustment distance and position parameter of the vibration table plane to the controller A, and compares it with the external set position parameter, and then controls the whole system. At this point, the position closed-loop control of the vibration table, the displacement closed-loop control of the vibration isolation device, and the pressure closed-loop control of the additional air chamber are constructed to control the whole system.

[0042] The oil tank 1, filter 2, high-pressure ball valve 3, variable pump 4, drive motor 5, one-way valve 6, safety valve 7, pressure reducing valve 8, pressure sensor 1 9, energy accumulator 10, oil temperature gauge 11, servo valve 12, servo hydraulic cylinder 13, water injection device 14, water injection pipeline 15, stop valve 16, vibration isolation device base 18, air spring 19, additional air chamber support frame 20, vibration isolation device upper top plate 21, additional air chamber 22, additional air chamber base 23, elastic air bag 24, pressure sensor 2 25, sealing rubber ring 26, upper sealing top plate 27, communication pipeline 28, controller A, controller B, displacement sensor, position-pressure conversion device of the present embodiment all use existing products or structures well known to those skilled in the art, and the connection or control mode between them also uses the existing connection or control mode well known to those skilled in the art, which will not be described in detail here.

[0043] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A variable air spring volume vibration isolation device with adjustable stiffness, characterized in that, The device includes a vibration isolation device base (18) for fixing to the foundation. The upper part of the base (18) has a flared quadrangular pyramidal structure. Four sets of adjustable-volume air springs (19) are evenly arranged on the four inner sides of the flared quadrangular pyramidal structure. The flared quadrangular pyramidal structure is fixed to the top plate (21) of the vibration isolation device with quadrangular pyramidal sides via the air springs (19). An auxiliary air chamber (22) for adjusting the stiffness of the air springs (19) is formed inside the top plate (21). The bottom of the auxiliary air chamber (22) is connected to the four sets of air springs (19), and the top of the auxiliary air chamber (22) is connected to a hydraulic system for injecting water and pressurizing the auxiliary air chamber (22). A device for fixing is formed on the top plate (21). An auxiliary air chamber support frame (20) for a fixed auxiliary air chamber (22) is provided. The auxiliary air chamber (22) includes an auxiliary air chamber base (23). An upper sealing top plate (27) is fixed on the upper part of the auxiliary air chamber base (23). An auxiliary air chamber is formed between the upper sealing top plate (27) and the auxiliary air chamber base (23). An elastic airbag (24) is fixed on the upper part of the auxiliary air chamber base (23). The elastic airbag (24) divides the auxiliary air chamber into a water injection chamber for communication with the hydraulic system and a pressurization chamber for communication with four air springs. A pressure sensor (25) is installed on the inner side wall of the auxiliary air chamber base (23) corresponding to the pressurization chamber. A sealing rubber ring (26) is installed at the connection between the upper sealing top plate (27) and the auxiliary air chamber base (23).

2. The variable air spring volume vibration isolation device with adjustable stiffness as described in claim 1, characterized in that, The air spring (19) is set at a 45-degree angle to the horizontal bottom surface of the vibration isolation device base (18).

3. The variable air spring volume vibration isolation device with adjustable stiffness as described in claim 1, characterized in that, The tilt angle and direction of the truncated quadrangular side of the top plate (21) of the vibration isolation device are the same as the tilt angle and direction of the flared quadrangular pyramid structure.

4. The variable air spring volume vibration isolation device with adjustable stiffness as described in claim 1, characterized in that, The vibration isolation device has a connecting pipe (28) formed in the top plate (21) that connects the bottom of the four sets of air springs (19) and the auxiliary air chamber (22).

5. The variable air spring volume vibration isolation device with adjustable stiffness as described in claim 1, characterized in that, The additional air chamber (22) is coaxially arranged with the base (18) of the vibration isolation device.

6. The variable air spring volume vibration isolation device with adjustable stiffness as described in claim 1, characterized in that, The hydraulic system includes an oil tank (1), a filter (2), a high-pressure ball valve (3), a variable pump (4), a drive motor (5), a check valve (6), a safety valve (7), a pressure reducing valve (8), a pressure sensor (9), an accumulator (10), an oil temperature gauge (11), a servo valve (12), a servo hydraulic cylinder (13), a water injection device (14), a water injection pipeline (15), and a shut-off valve (16). The drive motor (5) drives the variable pump (4). The inlet of the variable pump (4) is connected to the oil tank (1) in sequence through the high-pressure ball valve (3) and the filter (2). The outlet of the variable pump (4) is connected to the inlet of the check valve (6). The outlet of the check valve (6) is divided into two paths: one path is connected to the oil tank (1) through the safety valve (7), and the other path... The oil inlet of the servo hydraulic cylinder (13) is connected to the pressure reducing valve (8) and the servo valve (12) in sequence. The oil return port of the servo hydraulic cylinder (13) is connected to the oil tank (1) through the servo valve (12). The piston rod of the servo hydraulic cylinder (13) is fixed to the piston rod of the water injection device (14). The water outlet of the water injection device (14) is connected to the water inlet of the shut-off valve (16) through the water injection pipeline (15). The water outlet of the shut-off valve (16) is connected to the auxiliary air chamber (22). The oil inlet of the pressure reducing valve (8) is also connected to the accumulator (10). A pressure sensor (9) is installed on the pipeline connecting the accumulator (10) and the pressure reducing valve (8). An oil temperature gauge (11) is installed on the pipeline connecting the oil outlet of the pressure reducing valve (8) and the servo valve (12).

7. The control method for the adjustable stiffness variable air spring volume vibration isolation device as described in claim 6, characterized in that, Includes the following steps: Step 1: Fix the device to the vibration table via the top plate (21) of the vibration isolation device; install a displacement sensor on the vibration isolation device to detect the displacement parameters of the vibration table; connect the hydraulic system of the vibration isolation device, pressure sensor 2 (25) to controller B and position-pressure conversion device, and connect the displacement sensor, controller B, position-pressure conversion device to controller A. Step 2: Input the initial position information parameters of the required vibration table into controller A, then subtract the position distance signal of the vibration table detected by the displacement sensor from the input position signal to obtain the difference position signal, input the difference position signal to the position-pressure conversion device to obtain the pressure signal; subtract the converted pressure signal from the pressure signal fed back by the pressure sensor 2 (25) of the auxiliary air chamber (22) to obtain the difference between the expected pressure and the actual pressure, then input the difference into controller B, give the pressure control signal through the difference, input the pressure control signal to the pressure-displacement conversion device, and through the device, convert the pressure difference signal into a displacement position signal; At the same time, the controller B outputs the transformed displacement position signal to the servo valve (12). After receiving the signal, the servo valve (12) adjusts the working position of the servo hydraulic cylinder (13) according to the difference. The displacement of the piston rod of the servo hydraulic cylinder (13) drives the piston rod of the water injection device (14) to move, thereby pressurizing or depressurizing the elastic air bladder (24) of the auxiliary air chamber (22), causing internal pressure change. The pressure sensor two (25) in the pressurization chamber collects the pressure change and simultaneously feeds back the pressure change parameter to the controller B. The controller B calculates the difference between the pressure fed back by the pressure sensor two (25) and the pressure parameter of the position-pressure conversion until the two pressures are equal. Step 3: When the vibration table is subjected to external force and its position shifts, the displacement sensor detects the relevant displacement parameter signals of the vibration table and adjusts them in the manner of Step 2 to achieve closed-loop control of the position of the vibration table, the position of the vibration isolation device, and the pressure of the additional air chamber.

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