An adaptive variable stiffness and variable damping vibration isolator

Abstract

The present invention discloses an adaptive variable stiffness variable damping vibration isolator, comprising a vibration isolation unit and an electromagnetic actuator unit; the vibration isolation unit comprises a base, a vibration isolation element and a load platform, the vibration isolation element is arranged on the base for supporting the load platform; the electromagnetic actuator unit comprises a first electromagnet, a second electromagnet and a variable stiffness variable damping control unit; the second electromagnet is arranged on the base, the first electromagnet is located below the load platform and is arranged opposite to the second electromagnet; the variable stiffness variable damping control unit comprises a vibration sensor, a main control board and a current control module. The present invention adopts a damping and stiffness intelligent control strategy associated with f / f0, which can effectively control vibrations with a wide frequency band and a large dynamic load range, significantly improve the vibration isolation performance of traditional vibration isolation systems, and achieve broadband vibration isolation.

Description

Technical Field

[0001] The invention relates to the technical field of vibration and noise control, and in particular to an adaptive variable stiffness and variable damping vibration isolator. Background Art

[0002] Active and passive vibration isolation technologies are widely used in the field of electromechanical equipment and engineering technology. Spring isolators with fixed stiffness are widely used in vibration isolation systems due to their advantages such as low natural frequency, high stiffness, and strong load capacity. However, the vibration isolation efficiency of spring isolators in the low frequency band is obviously insufficient, and when the vibration source frequency f is less than or equal to √2 times the natural frequency f 0 When the vibration transmission rate is greater than 1, the amplitude of the object isolated above the isolator is large, which creates safety hazards and reduces the service life of the equipment.

[0003] The patent specification with publication number CN104455139A discloses a spring vibration isolation device based on adaptive electromagnetic damping. The magnitude and direction of the current in the coil are controlled by a variable resistor, so that the direction of the electromagnetic damping force of the magnetic field on the energized coil is always opposite to the direction of the vibration speed, so as to meet the vibration isolation requirements of different occasions. The vibration isolation system disclosed in the patent has the following defects: first, the coil of the system is fixed or wound with the spring, resulting in a relatively small number of coil turns in the permanent magnet magnetic field, a relatively short total length of the wire, a limited electromagnetic force, and great technical difficulty in fixing the coil and the spring; second, the direction of the electromagnetic force generated by the vibration isolation system is always opposite to the direction of the vibration speed of the vibration source, that is, only electromagnetic damping is generated to suppress the vibration of the vibration source, and no negative stiffness control strategy is introduced.

[0004] The patent specification with publication number CN113446352A discloses a vibration isolation system and process, including a housing, a thrust shaft is arranged on the vertical center axis of the housing, an electromagnetic device is arranged below the thrust shaft, an armature is arranged horizontally at the center of the electromagnetic device, the armature is connected to a support rod, and the support rod is connected to a tray to provide support force for the tray. This solution suppresses the vertical vibration of an object by the difference in suction force of the electromagnets located on the upper and lower sides of the armature to the armature.

[0005] The vibration isolation system disclosed in the patent has the following defects: the control strategy of the system is to adjust the suction force of the electromagnet on the armature by connecting the power amplifier through a differential current controller to adjust the coil current, which is equivalent to introducing electromagnetic damping, but does not introduce negative stiffness, that is, it adopts a single variable damping strategy. Under this control strategy, when f / f 0 ≤√2, the greater the system damping, the better the vibration isolation effect, and the vibration transmission rate is greater than 1; when f / f 0 >√2, the smaller the system damping, the better the vibration isolation effect, and the vibration transmission rate is less than 1, that is, the system can only reduce f / f by introducing electromagnetic damping alone 0The vibration transmissibility when ≤√2 is still greater than 1, and the frequency band in which electromagnetic damping works on the vibration isolation efficiency is relatively narrow. The present invention can achieve a vibration isolation effect that is significantly better than the above-mentioned patent by introducing electromagnetic damping and negative stiffness (relative to the positive stiffness of the vibration isolation element) and adopting corresponding control strategies according to the vibration frequency of the vibration source. Summary of the invention

[0006] The object of the present invention is to provide an adaptive variable stiffness variable damping vibration isolator, which adopts the f / f 0 The associated intelligent control strategy of damping and stiffness can effectively control vibrations with a wide frequency band and a large dynamic load range, significantly improve the vibration isolation performance of traditional vibration isolation systems, and achieve broadband vibration isolation.

[0007] An adaptive variable stiffness variable damping vibration isolator, comprising a vibration isolation unit and an electromagnetic actuator unit; the vibration isolation unit comprises a base, a vibration isolation element and a load platform, the vibration isolation element is arranged on the base for supporting the load platform;

[0008] The electromagnetic actuator unit includes a first electromagnet, a second electromagnet and a variable stiffness and variable damping control unit; the second electromagnet is arranged on the base, and the first electromagnet is located below the load platform and is arranged opposite to the second electromagnet;

[0009] The variable stiffness and variable damping control unit includes a vibration sensor, a main control board and a current control module; the vibration sensor is fixed on the load platform, and the main control board is electrically connected to the vibration sensor and the current control module respectively. The main control board obtains the vibration direction, exciting force and frequency information of the load platform by analyzing the vibration signal sensed by the vibration sensor, and determines the damping and stiffness control strategy of the vibration isolator. The current control module adjusts the current size and direction of the electromagnet according to the control strategy, so that the electromagnetic actuator unit generates the required damping force or equivalent negative stiffness, thereby realizing adaptive adjustment of the damping and stiffness of the vibration isolator.

[0010] Preferably, the first electromagnet is fixedly connected to the load platform.

[0011] Further preferably, according to the vibration frequency f of the vibration source and the initial natural frequency f of the system 0 , adopt the following damping and stiffness control strategies:

[0012] When the vibration frequency f of the vibration source is equal to the natural frequency f of the system 0 When the ratio of f / f is less than or equal to 1, the variable stiffness variable damping control unit makes the electromagnetic force generated by the electromagnetic actuator unit opposite to the vibration direction of the vibration source. Thus, the system adaptively introduces the required nonlinear electromagnetic damping so that the electromagnetic damping force offsets the unbalanced force acting on the load platform. When 1<f / f 0≤√2, the variable stiffness variable damping control unit makes the direction of the electromagnetic force generated by the electromagnetic actuator unit consistent with the vibration direction of the vibration source, so that the system adaptively introduces the required nonlinear negative stiffness. At this time, the electromagnetic damping is zero, but non-electromagnetic damping exists in the system; when f / f 0 >√2, the variable stiffness variable damping control unit makes the direction of the electromagnetic force generated by the electromagnetic actuator unit consistent with the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear negative stiffness.

[0013] Preferably, the first electromagnet is fixedly connected to the base, and the electromagnetic actuator unit further comprises an armature located between the first electromagnet and the second electromagnet, wherein the armature is arranged on the top of the vibration isolation element and is fixedly connected to the load platform.

[0014] Further preferably, according to the vibration frequency f of the vibration source and the initial natural frequency f of the system 0 , adopt the following damping and stiffness control strategies:

[0015] When the vibration frequency f of the vibration source is equal to the natural frequency f of the system 0 When the ratio of f / f is less than or equal to 1, the variable stiffness variable damping control unit makes the direction of the magnetic attraction between the electromagnet and the armature opposite to the vibration direction of the vibration source. Thus, the system adaptively introduces the required nonlinear electromagnetic damping, so that the electromagnetic damping force offsets the unbalanced force acting on the load platform. When 1<f / f 0 ≤√2, the variable stiffness variable damping control unit makes the direction of the magnetic attraction between the electromagnet and the armature consistent with the vibration direction of the vibration source, so that the system adaptively introduces the required nonlinear negative stiffness. At this time, the electromagnetic damping is zero, but non-electromagnetic damping exists in the system; when f / f 0 >√2, the variable stiffness variable damping control unit makes the direction of the magnetic attraction between the electromagnet and the armature consistent with the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear negative stiffness.

[0016] Preferably, the number of electromagnets is one or more pairs, wherein one or more pairs of electromagnets are used to generate electromagnetic damping, and another one or more pairs of electromagnets generate negative stiffness; or the same pair of electromagnets generates the required electromagnetic damping or negative stiffness according to the vibration frequency of the vibration source and the control strategy.

[0017] Preferably, the vibration isolation element is a steel spring, an air spring or a rubber vibration isolation pad.

[0018] Preferably, one or more vibration isolation elements are provided.

[0019] The working principle of the above-mentioned adaptive variable stiffness variable damping vibration isolator is as follows:

[0020] The main control board obtains information such as the vibration direction, exciting force and frequency (f) of the load platform in the vibration isolation unit by analyzing the vibration signal sensed by the vibration sensor, and determines the damping and stiffness control strategy of the vibration isolator. The current control module adjusts the magnitude and direction of the power-on current according to the control strategy, and the actuator generates the required damping force or equivalent negative stiffness, thereby realizing adaptive adjustment of the damping and stiffness of the vibration isolator.

[0021] The variable stiffness variable damping control unit is based on the vibration frequency (excitation frequency) f of the vibration source and the initial natural frequency f of the system. 0 , the following damping and stiffness control strategies are adopted. When the excitation frequency f is equal to the system natural frequency f 0 When the ratio is ≤1, the greater the system damping, the greater the tuning ratio f / f 0 The smaller the vibration isolation effect, the better. The variable stiffness and variable damping control unit makes the direction of the electromagnetic force generated by the actuator opposite to the vibration direction of the vibration source. The system adaptively introduces the required nonlinear electromagnetic damping to make the electromagnetic damping force offset the unbalanced force acting on the load platform as much as possible. When 1<f / f 0 ≤√2, the greater the system damping, f / f 0 The larger the value, the better the vibration isolation effect. The variable stiffness and variable damping control unit makes the direction of the electromagnetic force generated by the actuator consistent with the vibration direction of the vibration source. Thus, the system adaptively introduces the required nonlinear negative stiffness, thereby reducing the natural frequency f of the system. 0 , indirectly increasing the tuning ratio f / f 0 To achieve broadband vibration isolation, the electromagnetic damping is zero, but the non-electromagnetic damping in the system (such as the viscous damping below the base and above the load platform in the vibration isolation unit) is as large as possible; when f / f 0 >√2, the system damping is smaller, f / f 0 The larger the value, the better the vibration isolation effect. The variable stiffness and variable damping control unit makes the direction of the electromagnetic force generated by the actuator consistent with the vibration direction of the vibration source. Thus, the system adaptively introduces the required nonlinear negative stiffness, and the damping of the entire system is as small as possible.

[0022] Beneficial effects of the present invention:

[0023] (1) The present invention introduces variable negative stiffness, which is coupled with the positive stiffness of the spring to achieve variable stiffness of the system (to achieve quasi-zero stiffness), thereby changing the natural frequency f of the system 0 , and indirectly adjust the tuning ratio (f / f 0 ) to achieve broadband vibration isolation.

[0024] (2) The present invention innovatively designs an adaptive variable stiffness and variable damping vibration isolator, which can adaptively adjust the control strategy according to the different tuning ratios and damping ratios, greatly promoting the iterative upgrade of vibration isolation technology in the fields of electromechanical equipment and engineering technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic longitudinal section diagram of Example 1 of the present invention;

[0026] Figure 2 It is a schematic longitudinal section diagram of Embodiment 2 of the present invention;

[0027] In the figure: 1. vibration sensor; 2. load platform; 3. pillar; 4. vibration isolation element; 5. first electromagnet; 6. second electromagnet; 7. base; 8. armature; 9. main control board; 10. current control module. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] like Figure 1 As shown, an adaptive variable stiffness and variable damping vibration isolator includes a vibration isolation unit and an electromagnetic actuator unit; the vibration isolation unit includes a base 7, a vibration isolation element 4 and a load platform 2, the electromagnetic actuator unit includes a first electromagnet 5, a second electromagnet 6 and a variable stiffness and variable damping control unit, and the variable stiffness and variable damping control unit includes a vibration sensor 1, a main control board 9 and a current control module 10.

[0031] The vibration isolation element 4 is connected to the load platform 2 at the top and to the base 7 at the bottom. In this embodiment, the vibration isolation element 4 is a steel spring, an air spring or a rubber vibration isolation pad, and four of them are provided and located at the four corners of the base 7 .

[0032] The first electromagnet 5 is connected to the load platform 2 via a support 3 , and the second electromagnet 6 is placed on a base 7 .

[0033] The main control board 9 obtains information such as the vibration direction, exciting force and frequency (f) of the load platform 2 in the vibration isolation unit by analyzing the vibration signal sensed by the vibration sensor 1, and determines the damping and stiffness control strategy of the vibration isolator. The current control module 10 adjusts the magnitude and direction of the power-on current according to the control strategy, so that the electromagnet generates the required damping force or equivalent negative stiffness, thereby realizing adaptive adjustment of the damping and stiffness of the vibration isolator.

[0034] The damping of the entire vibration isolation system includes two parts: one is the electromagnetic damping introduced by the electromagnetic actuator unit, and the other is non-electromagnetic damping such as viscous damping below the base and above the load platform in the vibration isolation unit.

[0035] The variable stiffness variable damping control unit is based on the vibration frequency (excitation frequency) f of the vibration source and the initial natural frequency f of the system. 0 , the following damping and stiffness control strategies are adopted. When the excitation frequency f is equal to the system natural frequency f 0 When the ratio of f / f is less than or equal to 1, the variable stiffness variable damping control unit makes the electromagnet generate an attractive or repulsive force opposite to the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear electromagnetic damping, so that the electromagnetic damping force can offset the unbalanced force acting on the load platform as much as possible; when 1<f / f 0 When ≤√2, the variable stiffness variable damping control unit makes the electromagnet generate an attractive or repulsive force consistent with the vibration direction of the vibration source, so that the system adaptively introduces the required nonlinear negative stiffness. At this time, the electromagnetic damping is zero, but the non-electromagnetic damping in the system (such as the viscous damping below the base and above the load platform in the vibration isolation unit) is as large as possible; when f / f 0 >√2, the variable stiffness and variable damping control unit makes the electromagnet generate an attractive or repulsive force consistent with the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear negative stiffness, and the damping of the entire system is as small as possible.

[0036] In the specific implementation process, the first electromagnet 5 and the second electromagnet 6 are both DC electromagnets. The number of electromagnets can be one pair or more pairs, where one or more pairs of electromagnets are used to generate electromagnetic damping, and another pair or more pairs of electromagnets generate negative stiffness. It can also be the same pair of electromagnets that generates the required electromagnetic damping or negative stiffness according to the vibration frequency of the vibration source and the control strategy.

[0037] In a specific implementation process, the electromagnet may be located inside or outside the vibration isolation element 4 .

[0038] Example 2

[0039] like Figure 2 As shown, an adaptive variable stiffness and variable damping vibration isolator includes a vibration isolation unit and an electromagnetic actuator unit; the vibration isolation unit includes a base 7, a vibration isolation element 4 and a load platform 2, the electromagnetic actuator unit includes a first electromagnet 5, a second electromagnet 6, an armature 8 and a variable stiffness and variable damping control unit, and the variable stiffness and variable damping control unit includes a vibration sensor 1, a main control board 9 and a current control module 10.

[0040] The first electromagnet 5 is supported by a support column 3 connected to a base 7 , the second electromagnet 6 is placed on the base 7 , the armature 8 is located between the first electromagnet 5 and the second electromagnet 6 and connects the vibration isolation element 4 and the load platform 2 .

[0041] The main control board 9 obtains information such as the vibration direction, exciting force and frequency (f) of the load platform 2 in the vibration isolation unit by analyzing the vibration signal sensed by the vibration sensor 1, and determines the damping and stiffness control strategy of the vibration isolator. The current control module 10 adjusts the electromagnets to be energized and the energizing current according to the control strategy, and the electromagnets generate the required damping force or equivalent negative stiffness, thereby realizing adaptive adjustment of the damping and stiffness of the vibration isolator.

[0042] The damping of the entire vibration isolation system includes two parts: one is the electromagnetic damping introduced by the electromagnetic actuator unit, and the other is non-electromagnetic damping such as viscous damping below the base and above the load platform in the vibration isolation unit.

[0043] The variable stiffness variable damping control unit is based on the vibration frequency (excitation frequency) f of the vibration source and the initial natural frequency f of the system. 0 , the following damping and stiffness control strategies are adopted. When the excitation frequency f is equal to the system natural frequency f 0 When the ratio of f / f is less than or equal to 1, the variable stiffness variable damping control unit makes the direction of the magnetic attraction between the electromagnet and the armature opposite to the vibration direction of the vibration source. Thus, the system adaptively introduces the required nonlinear electromagnetic damping, so that the electromagnetic damping force can offset the unbalanced force acting on the load platform as much as possible. When 1<f / f 0 When ≤√2, the variable stiffness variable damping control unit makes the direction of the magnetic attraction between the electromagnet and the armature consistent with the vibration direction of the vibration source, so that the system adaptively introduces the required nonlinear negative stiffness. At this time, the electromagnetic damping is zero, but the non-electromagnetic damping in the system (such as the viscous damping below the base and above the load platform in the vibration isolation unit) is as large as possible; when f / f 0 >√2, the variable stiffness and variable damping control unit makes the direction of the magnetic attraction between the electromagnet and the armature consistent with the vibration direction of the vibration source, so that the system adaptively introduces the required nonlinear negative stiffness, and the damping of the entire system is as small as possible.

[0044] In the specific implementation process, the first electromagnet 5 and the second electromagnet 6 can be DC electromagnets or AC electromagnets, and the number of electromagnets can be one pair or more pairs, wherein one or more pairs of electromagnets are used to generate electromagnetic damping, and another pair or more pairs of electromagnets generate negative stiffness. It can also be the same pair of electromagnets that generates the required electromagnetic damping or negative stiffness according to the vibration frequency of the vibration source and the control strategy.

[0045] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An adaptive variable stiffness and variable damping vibration isolator, characterized in that: It comprises a vibration isolation unit and an electromagnetic actuator unit; the vibration isolation unit comprises a base, a vibration isolation element and a load platform, and the vibration isolation element is arranged on the base to support the load platform; The electromagnetic actuator unit includes a first electromagnet, a second electromagnet and a variable stiffness and variable damping control unit; the second electromagnet is arranged on the base, and the first electromagnet is located below the load platform and is arranged opposite to the second electromagnet; The variable stiffness and variable damping control unit includes a vibration sensor, a main control board and a current control module; the vibration sensor is fixed on the load platform, and the main control board is electrically connected to the vibration sensor and the current control module respectively. The main control board obtains the vibration direction, exciting force and frequency information of the load platform by analyzing the vibration signal sensed by the vibration sensor, and determines the damping and stiffness control strategy of the vibration isolator. The current control module adjusts the current size and direction of the electromagnet according to the control strategy, so that the electromagnetic actuator unit generates the required damping force or equivalent negative stiffness, thereby realizing adaptive adjustment of the damping and stiffness of the vibration isolator.

2. The adaptive variable stiffness and variable damping vibration isolator according to claim 1, characterized in that: The first electromagnet is fixedly connected to the load platform.

3. The adaptive variable stiffness and variable damping vibration isolator according to claim 2, characterized in that: According to the vibration frequency f of the vibration source and the initial natural frequency f0 of the system, the following damping and stiffness control strategies are adopted: When the ratio of the vibration frequency f of the vibration source to the natural frequency f0 of the system is ≤1, the variable stiffness and variable damping control unit makes the direction of the electromagnetic force generated by the electromagnetic actuator unit opposite to the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear electromagnetic damping, so that the electromagnetic damping force offsets the unbalanced force acting on the load platform; when 1<f / f0≤√2, the variable stiffness and variable damping control unit makes the direction of the electromagnetic force generated by the electromagnetic actuator unit consistent with the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear negative stiffness, at this time the electromagnetic damping is zero, but non-electromagnetic damping exists in the system; when f / f0>√2, the variable stiffness and variable damping control unit makes the direction of the electromagnetic force generated by the electromagnetic actuator unit consistent with the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear negative stiffness.

4. The adaptive variable stiffness and variable damping vibration isolator according to claim 1, characterized in that: The first electromagnet is fixedly connected to the base, and the electromagnetic actuator unit further comprises an armature located between the first electromagnet and the second electromagnet. The armature is arranged on the top of the vibration isolation element and is fixedly connected to the load platform.

5. The adaptive variable stiffness and variable damping vibration isolator according to claim 4, characterized in that: According to the vibration frequency f of the vibration source and the initial natural frequency f0 of the system, the following damping and stiffness control strategies are adopted: When the ratio of the vibration frequency f of the vibration source to the natural frequency f0 of the system is ≤1, the variable stiffness variable damping control unit makes the direction of the magnetic attraction force between the electromagnet and the armature opposite to the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear electromagnetic damping, so that the electromagnetic damping force offsets the unbalanced force acting on the load platform; when 1<f / f0≤√2, the variable stiffness variable damping control unit makes the direction of the magnetic attraction force between the electromagnet and the armature consistent with the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear negative stiffness, at this time the electromagnetic damping is zero, but non-electromagnetic damping exists in the system; when f / f0>√2, the variable stiffness variable damping control unit makes the direction of the magnetic attraction force between the electromagnet and the armature consistent with the vibration direction of the vibration source, thereby the system adaptively introduces the required nonlinear negative stiffness.

6. The adaptive variable stiffness and variable damping vibration isolator according to claim 1, characterized in that: The number of electromagnets is one or more pairs, wherein one or more pairs of electromagnets are used to generate electromagnetic damping, and another one or more pairs of electromagnets generate negative stiffness; or the same pair of electromagnets generates the required electromagnetic damping or negative stiffness according to the vibration frequency of the vibration source and the control strategy.

7. The adaptive variable stiffness and variable damping vibration isolator according to claim 1, characterized in that: The vibration isolation element is a steel spring, an air spring or a rubber vibration isolation pad.

8. The adaptive variable stiffness and variable damping vibration isolator according to claim 1, characterized in that: The vibration isolation element is provided in one or more pieces.

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