Longitudinal thrust self-adaptive quasi-zero stiffness vibration isolator and self-adaptive regulation and control method

Abstract

The invention provides a longitudinal thrust self-adaptive quasi-zero stiffness vibration isolator and a self-adaptive regulation and control method. The longitudinal thrust self-adaptive quasi-zero stiffness vibration isolator comprises a transfer table and a frame. A longitudinal elastic assembly, a transverse elastic linkage assembly and a thrust self-adaptive adjusting assembly are arranged on the frame, the longitudinal elastic assembly comprises a longitudinal linear limiting structure and a longitudinal spring, and the adapter table is connected with the longitudinal linear limiting structure; the thrust self-adaptive adjusting assembly comprises a displacement sensor, an adjusting plate, a longitudinal adjusting motor and an adjusting control module, the longitudinal spring is pressed between the switching table and the adjusting plate, and the displacement sensor is arranged on the switching table or the adjusting plate and used for measuring the real-time relative displacement between the switching table and the adjusting plate; the relative displacement data is transmitted to the adjustment control module; the vibration isolation device can adapt to vibration characteristic changes of the propulsion device under the variable thrust working condition in real time, and stable isolation of longitudinal low-frequency and broadband vibration of the ship propulsion shafting is achieved.

Description

Technical Field

[0001] This invention relates to the field of ship vibration reduction and noise reduction technology, specifically to a longitudinal thrust adaptive quasi-zero stiffness vibration isolator and an adaptive control method. Background Technology

[0002] Low-frequency vibration noise from the propeller, transmitted longitudinally to the hull via the ship's propulsion shaft system, is a key factor causing underwater acoustic radiation and compromising the ship's acoustic stealth performance. Controlling the longitudinal vibration of the ship's propulsion shaft system by addressing the vibration transmission path is one of the most effective means to solve the problem of reduced acoustic stealth performance caused by low-frequency propeller vibration noise, and it has already been officially applied in engineering projects.

[0003] Currently, the longitudinal vibration control of ship shafting is mainly based on the principle of dynamic vibration absorbers, which can only effectively suppress vibrations in certain specific frequency bands. Under variable thrust conditions, the change in propeller speed leads to changes in the longitudinal vibration characteristics of the shafting. At the same time, in the vibration excitation generated by the propeller, the low-frequency part has a longer wavelength, and its propagation attenuation in water is smaller, resulting in a longer propagation distance. Therefore, it has become the main factor that undermines the stealth performance of submarines.

[0004] Currently, the main longitudinal vibration control schemes for ship propulsion shafts include two types: semi-active dynamic vibration absorbers and active dynamic vibration absorbers. Existing semi-active dynamic vibration absorbers can achieve good attenuation of vibrations within a specific narrow frequency band with low power consumption by adjusting parameters. Existing active dynamic vibration absorbers can achieve a relatively wide vibration attenuation frequency band by introducing actuators. However, both have the problem of a narrow vibration attenuation frequency band, especially with limited effect on suppressing low-frequency vibrations, and neither can meet the requirements for longitudinal low-frequency broadband vibration control of the shaft system.

[0005] Therefore, from the perspective of vibration isolation, it is extremely necessary to design an adaptive control method for a longitudinal quasi-zero stiffness vibration isolator for ship propulsion shafting with low power consumption, thrust adaptation, and low-frequency wideband vibration isolation functions based on nonlinear dynamics theory. Summary of the Invention

[0006] The purpose of this invention is to provide a longitudinal thrust adaptive quasi-zero stiffness vibration isolator and an adaptive control method, which aims to improve the problems in the existing longitudinal vibration control schemes for ship propulsion shafts, such as the narrow attenuation frequency band of the dynamic vibration absorber, poor low-frequency suppression effect, and inability to adapt to variable thrust conditions.

[0007] This invention is implemented as follows:

[0008] According to a first aspect of the present invention, the present invention provides a longitudinal thrust adaptive quasi-zero stiffness vibration isolator, comprising a transition platform connected to a propulsion device and connected to the hull of a ship via a frame; the frame is provided with a longitudinal elastic component, a lateral elastic linkage component, and a thrust adaptive adjustment component; the longitudinal elastic component includes a longitudinal linear limiting structure and a longitudinal spring; the transition platform is connected to the longitudinal linear limiting structure to limit the transition platform to translational motion only along the longitudinal direction; the thrust adaptive adjustment component includes a displacement sensor, an adjustment plate, a longitudinal adjustment motor, and an adjustment control module; the longitudinal spring is pressed between the transition platform and the adjustment plate; the displacement sensor is disposed on the transition platform or the adjustment plate and is used to measure the real-time relative displacement between the transition platform and the adjustment plate, and transmit the relative displacement data to the adjustment control module, providing real-time data input for the adjustment control module to determine changes in the thrust of the propulsion device and drive the longitudinal adjustment motor to adjust the position of the adjustment plate; the lateral elastic linkage component is connected to the transition platform and is used to convert the longitudinal displacement of the transition platform into lateral elastic deformation, forming a quasi-zero stiffness characteristic in conjunction with the longitudinal elastic component.

[0009] Furthermore, the lateral elastic linkage assembly includes a lateral slide rail, a horizontal slider, a spring rod, a lateral spring, and a connecting rod. Two lateral slide rails are provided, respectively located on the front and rear sides of the transition platform. Two horizontal sliders are slidably mounted on each of the two lateral slide rails. A pair of horizontal sliders facing each other on the two lateral slide rails are connected by a spring rod. The two spring rods are located on the left and right sides of the transition platform, respectively. Two lateral springs are provided, respectively located on the front and rear sides of the transition platform. The two ends of each lateral spring are connected to the two spring rods. A boss is provided on each of the left and right sides of the transition platform. Two connecting rods are provided, respectively located on the left and right sides of the transition platform. The right end of the left connecting rod is rotatably connected to the boss on the left side of the transition platform via a rolling bearing and a short shaft. The left end of the left connecting rod is rotatably connected to the spring rod on the left side via a rolling bearing and a short shaft. The right end of the right connecting rod is rotatably connected to the boss on the right side of the transition platform via a rolling bearing and a short shaft.

[0010] Furthermore, the spring rod is provided with two spring hooking structures, and the two ends of the transverse spring are provided with hooks, and the transverse spring is connected to the spring hooking structures on the spring rod through the hooks.

[0011] Furthermore, the adapter platform is provided with a first annular groove adapted to the longitudinal spring, and the adjustment plate is provided with a second annular groove adapted to the longitudinal spring, with the two ends of the longitudinal spring respectively embedded in the first annular groove and the second annular groove.

[0012] Furthermore, the longitudinal linear limiting structure includes an optical axis and a linear bearing. There are two optical axes arranged in parallel, and both ends of the optical axes are connected to the frame. Two linear bearings are provided on the transfer platform, and the two linear bearings are slidably connected to the two optical axes respectively.

[0013] Furthermore, the longitudinal adjustment motor is fixedly mounted on the frame, and the output shaft of the longitudinal adjustment motor is connected to a lead screw that rotates coaxially. The lead screw is arranged parallel to the optical axis, and the adjustment plate is provided with an internal threaded hole adapted to the lead screw. The lead screw passes through and is threaded into the internal threaded hole.

[0014] Furthermore, the adjustment control module includes an adaptive controller and a longitudinal motor controller. The displacement sensor and the longitudinal motor controller are both electrically connected to the adaptive controller, and the longitudinal adjustment motor is electrically connected to the longitudinal motor controller.

[0015] According to a first aspect of the present invention, the present invention provides an adaptive control method for the above-mentioned longitudinal thrust adaptive quasi-zero stiffness vibration isolator, comprising the following steps:

[0016] S1. The longitudinal linear limiting structure of the longitudinal elastic component limits the transfer platform to only translate longitudinally. At the same time, the longitudinal spring provides longitudinal support for the transfer platform. In conjunction with the transverse elastic linkage component, the longitudinal displacement of the transfer platform is converted into transverse elastic deformation, thus ensuring that the vibration isolator forms quasi-zero stiffness characteristics.

[0017] S2. Measure the instantaneous relative displacement of the longitudinal spring using a displacement sensor and transmit the measurement data to the adjustment and control module;

[0018] S3. The adjustment and control module calculates the instantaneous thrust output value based on the instantaneous relative displacement of the longitudinal spring through a filtering algorithm and a thrust frequency threshold.

[0019] S4. The adjustment and control module drives the longitudinal adjustment motor to adjust the compression of the longitudinal spring based on the instantaneous thrust output value, so that the longitudinal thrust adapts to the output of the quasi-zero stiffness vibration isolator to stabilize the reference thrust.

[0020] Furthermore, in step S1, it is assumed that the stiffness of the longitudinal spring is... The stiffness of the transverse spring is If the length of the transverse spring in its natural state is B, and the effective length of the connecting rod is L, then the above parameters satisfy the following relationship:

[0021]

[0022] Wherein, the effective length L of the connecting rod is the straight-line distance between the two ends of the connecting rod and the rotational engagement center point of the boss and the spring rod.

[0023] Furthermore, the specific processes of steps S3 and S4 are as follows:

[0024] Assume that the instantaneous relative displacement time-domain sampled data is stored in variables In this process, the Fast Fourier Transform algorithm is used to convert it into frequency domain data. ;

[0025] Thrust frequency threshold is set based on the thrust range of longitudinal thrust variation in the ship's shafting. Filter and store the thrust frequency domain data into variables. ;

[0026] use Perform an inverse Fourier transform to obtain the time-domain value of the thrust change and store it in a variable. ;

[0027] thrust The corresponding relative displacement change is input to the longitudinal motor controller, which controls the longitudinal adjustment motor to perform adjustment actions, so that the longitudinal thrust adaptive quasi-zero stiffness vibration isolator dynamically adapts to the thrust change, maintains the quasi-zero stiffness balance state, and achieves stable isolation of the longitudinal low-frequency broadband vibration of the propulsion device.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. This invention constructs a quasi-zero stiffness structure by using "longitudinal elastic components + transverse elastic linkage components" and combines it with the thrust adaptive logic of "displacement sensing - closed-loop control - motor adjustment". This not only solves the shortcomings of traditional dynamic vibration absorbers, such as narrow attenuation frequency band and weak low-frequency suppression capability, but also adapts to the vibration characteristics changes of the propulsion device under variable thrust conditions in real time. Ultimately, it achieves stable isolation of longitudinal low-frequency broadband vibration of the ship's propulsion shaft system, effectively ensuring the underwater acoustic stealth performance of the ship.

[0030] 2. This invention, through the combination of a "longitudinal linear limiting structure + longitudinal spring + transverse elastic linkage component", can ensure that the transfer platform moves smoothly only in the longitudinal direction by means of the longitudinal linear limiting structure, avoiding interference of transverse offset on the vibration transmission path. At the same time, the transverse elastic linkage component can convert the longitudinal displacement of the transfer platform into the deformation of the transverse spring, which works in conjunction with the longitudinal spring to form a quasi-zero stiffness characteristic, greatly reducing the equivalent stiffness of the system and significantly improving the isolation capability of the longitudinal low-frequency vibration of the propulsion device, thus making up for the defect of poor low-frequency suppression effect of traditional vibration absorbers.

[0031] 3. This invention, by setting up a thrust adaptive adjustment module consisting of a displacement sensor, an adaptive controller, a longitudinal motor controller, and a longitudinal adjustment motor, can collect the relative displacement data of the longitudinal spring in real time. After the adaptive controller analyzes and identifies the thrust changes, the longitudinal motor controller drives the motor to adjust the position of the adjustment plate and the spring compression, thereby achieving dynamic compensation for thrust changes. It can adapt to the variable thrust conditions of the propulsion device without manual intervention, solving the problem of detuning in traditional solutions. At the same time, the modular design facilitates later maintenance and installation adaptation for shipboard scenarios, improving the reliability of engineering applications. Attached Figure Description

[0032] Figure 1 This is an installation diagram of a longitudinal thrust adaptive quasi-zero stiffness vibration isolator provided by the present invention;

[0033] Figure 2 This is a cross-sectional view of a longitudinal thrust adaptive quasi-zero stiffness vibration isolator provided by the present invention;

[0034] Figure 3 This is a partial cross-sectional view of a longitudinal thrust adaptive quasi-zero stiffness vibration isolator provided by the present invention;

[0035] Figure 4 This is a schematic diagram of the thrust adaptive part of a longitudinal thrust adaptive quasi-zero stiffness vibration isolator provided by the present invention.

[0036] In the diagram: 1. Adapter platform; 2. Propulsion device; 3. Frame; 4. Hull; 5. Linear bearing; 6. Optical axis; 7. Longitudinal spring; 8. First annular groove; 9. Adjusting plate; 10. Second annular groove; 11. Internal threaded hole; 12. Lead screw; 13. Longitudinal adjusting motor; 14. Motor mounting plate; 15. Transverse slide rail; 16. Horizontal slider; 17. Spring hanging rod; 18. Transverse spring; 19. Connecting rod; 20. Boss; 21. Displacement sensor; 22. Adaptive controller; 23. Longitudinal motor controller. Detailed Implementation

[0037] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details:

[0039] Example 1

[0040] like Figures 1-4 As shown, this embodiment provides a longitudinal thrust adaptive quasi-zero stiffness vibration isolator, including a transition platform 1 and a frame 3. The transition platform 1 is connected to the propulsion device 2 of a ship, and is also connected to the hull 4 of the ship through the frame 3. The frame 3 is provided with a longitudinal elastic component, a lateral elastic linkage component, and a thrust adaptive adjustment component. The longitudinal elastic component includes a longitudinal linear limiting structure and a longitudinal spring 7. The transition platform 1 is connected to the longitudinal linear limiting structure to limit the transition platform 1 to translation only in the longitudinal direction. The thrust adaptive adjustment component includes a displacement sensor 21, an adjustment plate 9, a longitudinal adjustment motor 13, and an adjustment control module. The transition platform 1 is provided with a first annular groove 8 adapted to the longitudinal spring 7, and the adjustment plate 9 is provided with a second annular groove 10 adapted to the longitudinal spring 7. The two ends of the longitudinal spring 7 are respectively embedded in the first annular groove 8 and the second annular groove 10, and the longitudinal spring 7 is pressed between the transition platform 1 and the adjustment plate 9. The displacement sensor 21 is installed on the adjustment plate 9. The displacement sensor 21 measures the real-time relative displacement between the transfer platform 1 and the adjustment plate 9 by means of laser or wire, and transmits the relative displacement data to the adjustment control module. This provides real-time data input for the adjustment control module to judge the thrust change of the propulsion device 2 and drive the longitudinal adjustment motor 13 to adjust the position of the adjustment plate 9. The lateral elastic linkage component is connected to the transfer platform 1 and is used to convert the longitudinal displacement of the transfer platform 1 into lateral elastic deformation, which works with the longitudinal elastic component to form a quasi-zero stiffness characteristic.

[0041] like Figures 2-4As shown, the lateral elastic linkage assembly includes a lateral slide rail 15, horizontal sliders 16, spring rods 17, lateral springs 18, and connecting rods 19. Two lateral slide rails 15 are provided, located on the front and rear sides of the transfer platform 1, respectively. Each of the two lateral slide rails 15 has two horizontal sliders 16 slidably mounted on it. The pair of horizontal sliders 16 on the two lateral slide rails 15 are connected by a spring rod 17, which is located on the left and right sides of the transfer platform 1, respectively. Two lateral springs 18 are provided, located on the front and rear sides of the transfer platform 1, respectively. The two ends of each lateral spring 18 are connected to the two spring rods 17. Specifically, the spring rod 17 has two spring-hook structures, which can be hooks or annular hook grooves on the spring rod 17. The two ends of the lateral springs 18 are provided with hooks, and the lateral springs 18 are connected to the spring-hook structures on the spring rods 17 via these hooks. Each side of the adapter platform 1 has a boss 20, and there are two connecting rods 19, located on the left and right sides of the adapter platform 1 respectively. The right end of the left connecting rod 19 is rotatably connected to the boss 20 on the left side of the adapter platform 1 via a rolling bearing and a short shaft, and the left end of the left connecting rod 19 is rotatably connected to the left spring hanging rod 17 via a rolling bearing and a short shaft. The left end of the right connecting rod 19 is rotatably connected to the boss 20 on the right side of the adapter platform 1 via a rolling bearing and a short shaft, and the right end of the right connecting rod 19 is rotatably connected to the right spring hanging rod 17 via a rolling bearing and a short shaft.

[0042] like Figures 2-4 As shown, the longitudinal linear limiting structure includes an optical axis 6 and linear bearings 5. Two optical axes 6 are provided, and these two optical axes 6 are arranged in parallel. Both ends of the optical axes 6 are connected to the frame 3. Two linear bearings 5 ​​are provided on the adapter 1, and these two linear bearings 5 ​​are slidably connected to the two optical axes 6 respectively. The longitudinal adjusting motor 13 is fixedly mounted on the frame 3 via a motor mounting plate 14. The output shaft of the longitudinal adjusting motor 13 is connected to a coaxially rotating lead screw 12, which is arranged parallel to the optical axis 6. The adjusting plate 9 is provided with an internal threaded hole 11 adapted to the lead screw 12, through which the lead screw 12 passes and is threaded into the internal threaded hole 11.

[0043] like Figure 4 As shown, the adjustment control module includes an adaptive controller 22 and a longitudinal motor controller 23, which together constitute the core unit of the vibration isolator's "data processing-execution control". The displacement sensor 21 and the longitudinal motor controller 23 are both electrically connected to the adaptive controller 22. The displacement sensor 21 is used to stably transmit the real-time relative displacement data (such as voltage signals or digital signals) between the transfer platform 1 and the adjustment plate 9 to the adaptive controller 22. The longitudinal motor controller 23 is used to receive the thrust adjustment commands output by the adaptive controller 22. The longitudinal adjustment motor 13 is electrically connected to the longitudinal motor controller 23 and rotates in both forward and reverse directions under the drive of the longitudinal motor controller 23.

[0044] Example 2

[0045] This embodiment provides an adaptive control method for the longitudinal thrust adaptive quasi-zero stiffness vibration isolator provided in Embodiment 1, comprising the following steps:

[0046] S1. The longitudinal linear limiting structure of the longitudinal elastic component restricts the transfer platform 1 to translate only longitudinally. Simultaneously, the longitudinal spring 7 provides longitudinal support for the transfer platform 1. In conjunction with the transverse elastic linkage component, the longitudinal displacement of the transfer platform 1 is converted into transverse elastic deformation, thus ensuring the vibration isolator achieves quasi-zero stiffness characteristics. Assume the stiffness of the longitudinal spring 7 is... The stiffness of the transverse spring 18 is If the length of the transverse spring 18 in its natural state is half of B, and the effective length of the connecting rod 19 is L, then the above parameters satisfy the following relationship:

[0047]

[0048] Wherein, the effective length L of the connecting rod 19 is the straight-line distance between the two ends of the connecting rod 19 and the rotational engagement center point of the boss 20 and the spring hanging rod 17.

[0049] S2. The instantaneous relative displacement of the longitudinal spring 7 is measured by the displacement sensor 21, and the measurement data is transmitted to the adjustment and control module.

[0050] S3. The adjustment and control module calculates the instantaneous thrust output value based on the instantaneous relative displacement of the longitudinal spring 7 through a filtering algorithm and the thrust frequency threshold.

[0051] S4. The adjustment and control module drives the longitudinal adjustment motor 13 to adjust the compression of the longitudinal spring 7 based on the instantaneous thrust output value, so that the longitudinal thrust adapts to the output of the quasi-zero stiffness vibration isolator to stabilize the reference thrust.

[0052] The specific processes of steps S3 and S4 are as follows:

[0053] Assume that the instantaneous relative displacement time-domain sampled data is stored in variables In this process, the Fast Fourier Transform algorithm is used to convert it into frequency domain data. ;

[0054] Thrust frequency threshold is set based on the thrust range of longitudinal thrust variation in the ship's shafting. Filter and store the thrust frequency domain data into variables. ;

[0055] use Perform an inverse Fourier transform to obtain the time-domain value of the thrust change and store it in a variable. ;

[0056] thrust The corresponding relative displacement change is input to the longitudinal motor controller 23, which controls the longitudinal adjustment motor 13 to perform adjustment action, so that the longitudinal thrust adaptive quasi-zero stiffness vibration isolator dynamically adapts to the thrust change, maintains the quasi-zero stiffness balance state, and achieves stable isolation of the longitudinal low-frequency broadband vibration of the propulsion device.

[0057] In summary, this invention constructs a quasi-zero stiffness structure by using a "longitudinal elastic component + transverse elastic linkage component" and combines it with a thrust adaptive logic of "displacement sensing - closed-loop control - motor adjustment". This not only solves the shortcomings of traditional dynamic vibration absorbers, such as narrow attenuation frequency band and weak low-frequency suppression capability, but also adapts in real time to the vibration characteristics changes of the propulsion device under variable thrust conditions. Ultimately, it achieves stable isolation of longitudinal low-frequency broadband vibration of the ship's propulsion shaft system, effectively ensuring the underwater acoustic stealth performance of the ship.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A longitudinal thrust adaptive quasi-zero stiffness vibration isolator, characterized in that, The system includes a transfer platform connected to the propulsion device and connected to the ship's hull via a frame. The frame is equipped with a longitudinal elastic component, a lateral elastic linkage component, and a thrust adaptive adjustment component. The longitudinal elastic component includes a longitudinal linear limiting structure and a longitudinal spring. The transfer platform is connected to the longitudinal linear limiting structure to restrict the transfer platform to translational motion only along the longitudinal direction. The thrust adaptive adjustment component includes a displacement sensor, an adjustment plate, a longitudinal adjustment motor, and an adjustment control module. The longitudinal spring is pressed between the transfer platform and the adjustment plate. The displacement sensor is mounted on the transfer platform or the adjustment plate to measure the real-time relative displacement between the transfer platform and the adjustment plate, and transmits the relative displacement data to the adjustment control module. This provides real-time data input for the adjustment control module to determine changes in the propulsion device's thrust and drive the longitudinal adjustment motor to adjust the position of the adjustment plate. The lateral elastic linkage component is connected to the transfer platform and converts the longitudinal displacement of the transfer platform into lateral elastic deformation, working in conjunction with the longitudinal elastic component to form a quasi-zero stiffness characteristic.

2. The longitudinal thrust adaptive quasi-zero stiffness vibration isolator according to claim 1, characterized in that, The lateral elastic linkage assembly includes a lateral slide rail, horizontal sliders, spring rods, lateral springs, and connecting rods. Two lateral slide rails are provided, located on the front and rear sides of the transition platform respectively. Two horizontal sliders are slidably mounted on each of the two lateral slide rails. A pair of horizontal sliders facing each other on the two lateral slide rails are connected by a spring rod, which is located on the left and right sides of the transition platform respectively. Two lateral springs are provided, located on the front and rear sides of the transition platform respectively, with both ends connected to the two spring rods. A boss is provided on each of the left and right sides of the transition platform. Two connecting rods are provided, located on the left and right sides of the transition platform respectively. The right end of the left connecting rod is rotatably connected to the boss on the left side of the transition platform via a rolling bearing and a short shaft, and the left end of the left connecting rod is rotatably connected to the left spring rod via a rolling bearing and a short shaft. The left end of the right connecting rod is rotatably connected to the boss on the right side of the transition platform via a rolling bearing and a short shaft, and the right end of the right connecting rod is rotatably connected to the right spring rod via a rolling bearing and a short shaft.

3. A longitudinal thrust adaptive quasi-zero stiffness vibration isolator according to claim 2, characterized in that, The spring rod is provided with two spring hook structures, and the two ends of the transverse spring are provided with hooks. The transverse spring is connected to the spring hook structures on the spring rod through the hooks.

4. A longitudinal thrust adaptive quasi-zero stiffness vibration isolator according to claim 1, characterized in that, The adapter platform is provided with a first annular groove adapted to a longitudinal spring, and the adjustment plate is provided with a second annular groove adapted to a longitudinal spring. The two ends of the longitudinal spring are respectively embedded in the first annular groove and the second annular groove.

5. A longitudinal thrust adaptive quasi-zero stiffness vibration isolator according to claim 2, characterized in that, The longitudinal linear limiting structure includes an optical axis and a linear bearing. There are two optical axes, which are arranged in parallel. The two ends of the optical axes are connected to the frame. There are two linear bearings on the transfer platform, and the two linear bearings are slidably connected to the two optical axes respectively.

6. A longitudinal thrust adaptive quasi-zero stiffness vibration isolator according to claim 5, characterized in that, The longitudinal adjustment motor is fixedly mounted on the frame. The output shaft of the longitudinal adjustment motor is connected to a lead screw that rotates coaxially. The lead screw is arranged parallel to the optical axis. The adjustment plate is provided with an internal threaded hole that matches the lead screw. The lead screw passes through and is threaded into the internal threaded hole.

7. A longitudinal thrust adaptive quasi-zero stiffness vibration isolator according to claim 6, characterized in that, The adjustment control module includes an adaptive controller and a longitudinal motor controller. The displacement sensor and the longitudinal motor controller are both electrically connected to the adaptive controller, and the longitudinal adjustment motor is electrically connected to the longitudinal motor controller.

8. An adaptive control method for the longitudinal thrust adaptive quasi-zero stiffness vibration isolator as described in claim 7, characterized in that, Includes the following steps: S1. The longitudinal linear limiting structure of the longitudinal elastic component limits the transfer platform to only translate longitudinally. At the same time, the longitudinal spring provides longitudinal support for the transfer platform. In conjunction with the transverse elastic linkage component, the longitudinal displacement of the transfer platform is converted into transverse elastic deformation, thus ensuring that the vibration isolator forms quasi-zero stiffness characteristics. S2. Measure the instantaneous relative displacement of the longitudinal spring using a displacement sensor and transmit the measurement data to the adjustment and control module; S3. The adjustment and control module calculates the instantaneous thrust output value based on the instantaneous relative displacement of the longitudinal spring through a filtering algorithm and a thrust frequency threshold. S4. The adjustment and control module drives the longitudinal adjustment motor to adjust the compression of the longitudinal spring based on the instantaneous thrust output value, so that the longitudinal thrust adapts to the output of the quasi-zero stiffness vibration isolator to stabilize the reference thrust.

9. The adaptive control method according to claim 8, characterized in that, In step S1, it is assumed that the stiffness of the longitudinal spring is... The stiffness of the transverse spring is If the length of the transverse spring in its natural state is B, and the effective length of the connecting rod is L, then the above parameters satisfy the following relationship: Wherein, the effective length L of the connecting rod is the straight-line distance between the two ends of the connecting rod and the rotational engagement center point of the boss and the spring rod.

10. The adaptive control method according to claim 9, characterized in that, The specific processes of steps S3 and S4 are as follows: Assume that the instantaneous relative displacement time-domain sampled data is stored in variables In this process, the Fast Fourier Transform algorithm is used to convert it into frequency domain data. ; Thrust frequency threshold is set based on the thrust range of longitudinal thrust variation in the ship's shafting. Filter and store the thrust frequency domain data into variables. ; use Perform an inverse Fourier transform to obtain the time-domain value of the thrust change and store it in a variable. ; thrust The corresponding relative displacement change is input to the longitudinal motor controller, which controls the longitudinal adjustment motor to perform adjustment actions, so that the longitudinal thrust adaptive quasi-zero stiffness vibration isolator dynamically adapts to the thrust change, maintains the quasi-zero stiffness balance state, and achieves stable isolation of the longitudinal low-frequency broadband vibration of the propulsion device.

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