An electromagnetic variable stiffness and variable damping vibration isolator

Abstract

The present invention discloses an electromagnetic vibration isolator with variable stiffness and variable damping, which comprises a load platform, a vibration isolation element, a coil wound around a cylinder body, a permanent magnet, a base and a variable stiffness and variable damping control unit; the vibration isolation element is arranged on the base to support the load platform, the cylinder body is fixed to the bottom of the load platform, and the permanent magnet is arranged on the base and located outside the coil; the variable stiffness and variable damping control unit comprises a main control board, a current control module and a vibration sensor; 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 purpose of the present invention is to provide an electromagnetic vibration isolator with variable stiffness and variable damping, which realizes variable system stiffness and damping by using the Ampere force and has a large dynamic adjustable range, providing a new solution for vibration control in the fields of electromechanical equipment and engineering technology.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration and noise control of electromechanical equipment, and particularly relates to an electromagnetic variable stiffness and variable damping vibration isolator. Background Art

[0002] In the fields of electromechanical equipment and engineering technology, there are a large number of problems such as equipment wear and reduced accuracy caused by structural vibration. To effectively control the influence of structural or system vibration, various active and passive vibration isolation devices have been developed and applied in practice. Passive vibration isolators such as spring vibration isolators and rubber vibration isolators are widely used in vibration isolation systems due to their simple structure and high reliability. However, once the performance parameters such as stiffness and damping of such vibration isolators are fixed, their adaptability to different vibration sources is weak and the vibration isolation efficiency in the low-frequency band is insufficient.

[0003] The patent specification with the publication number CN113446352A discloses a vibration isolation system and process, which changes the voltage of the coil through a power amplifier to generate an electromagnetic force opposite to the vibration displacement direction, thereby suppressing the vibration response of the structure. The vibration isolation system disclosed in this patent has the following defects: First, the system only detects the displacement signal of the tray, that is, the direction of the electromagnetic force generated by the system is only related to the vibration displacement direction, resulting in poor control effect on the vibration of the vibration source near the equilibrium position; Second, the system increases or decreases the current output of the coil through a differential controller to adjust the magnitude and direction of the electromagnetic force, and finally realizes vibration suppression. In this control strategy, neither a negative stiffness strategy is introduced nor a frequency division control strategy is adopted. Only a single variable damping control strategy is used. The electromagnetic damping only has a positive effect on the vibration isolation of a relatively narrow frequency band, and can only reduce the vibration transmission ratio when f / f0≤√2, and the vibration transmission ratio after vibration isolation is still greater than 1.

[0004] The patent specification with the publication number CN104455139A discloses a spring vibration isolation device based on adaptive electromagnetic damping, which controls the magnitude and direction of the current passing through the coil through a variable resistor, so that the direction of the electromagnetic damping force of the energized coil in the magnetic field is always opposite to the vibration velocity direction to meet the vibration isolation requirements in different occasions. The vibration isolation system disclosed in this patent has the following defects: First, the coil of the system is fixed or wound together with the spring, resulting in a relatively small number of coil turns and a relatively short total wire length in the magnetic field of the permanent magnet, and the generated electromagnetic force is limited in magnitude, and the technology of fixing the coil and the spring is difficult; Second, the direction of the electromagnetic force generated by this vibration isolation system is always opposite to the direction of the vibration velocity of the vibration source, that is, only electromagnetic damping is generated to suppress the vibration of the vibration source, and a negative stiffness control strategy is not introduced.

[0005] The present invention adjusts the connection mode between the coil and the vibration source, and determines different stiffness and damping control strategies according to different vibration frequencies of the vibration source, and can achieve a vibration isolation effect significantly better than the above patents. Summary of the Invention

[0006] The object of the present invention is to provide an electromagnetic vibration isolator with variable stiffness and variable damping, introducing a stiffness and damping control strategy based on the vibration frequency of the vibration source to achieve intelligent vibration control of electromechanical equipment.

[0007] An electromagnetic vibration isolator with variable stiffness and variable damping includes a load platform, a vibration isolation element, a coil wound around a cylinder, a permanent magnet, a base, and a variable stiffness and variable damping control unit; the vibration isolation element is arranged on the base to support the load platform, the cylinder is fixed at the bottom of the load platform, and the permanent magnet is arranged on the base and located outside the coil;

[0008] The variable stiffness and variable damping control unit includes a main control board, a current control module, and a vibration sensor; the vibration sensor is fixed on the load platform, the main control board is electrically connected to the vibration sensor and the current control module respectively, the main control board analyzes the vibration direction, exciting force magnitude, and frequency information of the load platform according to the vibration signal sensed by the vibration sensor, determines the stiffness and damping control strategy of the vibration isolator, and the current control module adjusts the magnitude and direction of the current passing through the coil according to the control strategy, thereby generating the required damping force or equivalent negative stiffness to achieve adaptive adjustment of the stiffness and damping of the vibration isolator.

[0009] Preferably, according to the vibration frequency f of the vibration source and the initial natural frequency f0 of the system, the following stiffness and damping control strategies are adopted:

[0010] When the ratio of the vibration frequency f of the vibration source to the natural frequency f0 of the system ≤ 1, the variable stiffness and variable damping control unit makes the direction of the Ampere force received by the energized coil in the magnetic field opposite to the vibration direction of the vibration source, so that the system adaptively introduces the required non-linear electromagnetic damping to cancel the unbalanced force acting on the load platform with the electromagnetic damping force; when 1 < f / f0 ≤ √2, the variable stiffness and variable damping control unit makes the direction of the Ampere force received by the energized coil in the magnetic field consistent with the vibration direction of the vibration source, so that the system adaptively introduces the required non-linear negative stiffness. At this time, the electromagnetic damping is zero, but there is non-electromagnetic damping in the system; when f / f0 > √2, the variable stiffness and variable damping control unit makes the direction of the Ampere force received by the energized coil in the magnetic field consistent with the vibration direction of the vibration source, so that the system adaptively introduces the required non-linear negative stiffness.

[0011] Preferably, the number of the permanent magnets is one pair or more pairs.

[0012] Preferably, the cylinder is made of non-magnetic material. <S

[0013] More preferably, the material of the cylinder is aluminum alloy or ceramic. [[ID=X]] [[ID=Y]]

[0014] Preferably, the vibration isolation element is a steel spring, an air spring, or a rubber vibration isolation pad.

[0015] Preferably, both ends of the vibration isolation element are provided with limiting members for fixing the vibration isolation element.

[0016] Preferably, one or more vibration isolation elements are provided.

[0017] The working principle of the above electromagnetic variable stiffness and variable damping vibration isolator is as follows:

[0018] The vibration sensor and the current module are both connected to the main control board. The main control board analyzes the vibration signal sensed by the vibration sensor to obtain information such as the vibration direction, excitation force and frequency (f) of the load platform, and determines the stiffness and damping control strategy of the vibration isolator accordingly. The current module adjusts the magnitude and direction of the coil current according to the control strategy, thereby generating the required damping force or equivalent negative stiffness, thereby realizing adaptive adjustment of the stiffness and damping of the vibration isolator.

[0019] The variable stiffness and damping control unit adopts the following stiffness and damping control strategy according to the vibration frequency of the vibration source (excitation frequency) f and the initial natural frequency f0 of the system. When the ratio of the excitation frequency f to the natural frequency f0 of the system is ≤1, the greater the system damping and the smaller the tuning ratio f / f0, the better the vibration isolation effect. The variable stiffness and damping control unit makes the direction of the Ampere force on the energized coil in the magnetic field 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 as much as possible; when 1<f / f0≤√2, the greater the system damping and the larger f / f0, the better the vibration isolation effect. The variable stiffness and damping control unit makes the direction of the Ampere force on the energized coil in the magnetic field 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 as much as possible; when 1<f / f0≤√2, the greater the system damping and the larger f / f0, the better the vibration isolation effect. The direction of the Ampere force is consistent with the vibration direction of the vibration source, so 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 / f0>√2, the smaller the system damping and the larger the f / f0, the better the vibration isolation effect. The variable stiffness and variable damping control unit makes the direction of the Ampere force on the energized coil in the magnetic field consistent with the vibration direction of the vibration source, so the system adaptively introduces the required nonlinear negative stiffness, and the damping of the entire system is as small as possible.

[0020] Beneficial effects of the present invention:

[0021] (1) The present invention introduces electromagnetic variable stiffness, which is coupled with the positive stiffness of vibration isolation elements such as springs and rubber, to achieve variable system stiffness (to achieve quasi-zero stiffness), thereby reducing the vibration transmissibility in the vibration isolation system.

[0022] (2) The present invention innovatively designs an electromagnetic variable stiffness and variable damping vibration isolator, which uses Ampere force to achieve variable system stiffness and damping with a large dynamic adjustable range, providing a new solution for vibration control in the fields of electromechanical equipment and engineering technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic longitudinal sectional view of an embodiment of the present invention.

[0024] In the figure: 1, vibration sensor; 2, load platform; 3, vibration isolation element; 4, coil; 5, permanent magnet; 6, base; 7, main control board; 8, current control module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0026] As Figure 1 shown, an electromagnetic variable stiffness and variable damping vibration isolator includes a load platform 2, a vibration isolation element 3, a coil 4 wound around a cylinder, a permanent magnet 5, a base 6, and a variable stiffness and variable damping control unit. The variable stiffness and variable damping control unit includes a main control board 7, a current control module 8, and a vibration sensor 1.

[0027] The vibration isolation element 3 is connected to the load platform 2 at the upper part and the base 6 at the lower part. In this embodiment, the vibration isolation element 3 is a steel spring, an air spring, or a rubber vibration isolation pad, and there are four of them, located at the four corners of the base 6.

[0028] In the specific implementation process, limiters can be provided at both ends of the vibration isolation element 3 to fix the vibration isolation element 3.

[0029] The coil 4 wound around the cylinder is arranged between the load platform 2 and the base 6. Specifically, the cylinder is fixed to the bottom of the load platform 2. In this embodiment, the cylinder is made of non-magnetic materials such as aluminum alloy, ceramics, etc., and the cylinder can be perforated or sewn.

[0030] The permanent magnet 5 is arranged on the base 6 and located outside the coil 4. In the specific implementation process, the number of permanent magnets 5 can be one pair or multiple pairs; the coil 4 wound around the cylinder needs to be energized with direct current.

[0031] The vibration sensor 1 is located on the load platform 2 and is used to sense vibration signals. Both the vibration sensor 1 and the current module 8 are connected to the main control board 7. The main control board 7 analyzes the vibration direction, excitation force magnitude, and frequency (f) and other information of the load platform 2 based on the vibration signals sensed by the vibration sensor 1, and determines the vibration isolator stiffness and damping control strategies accordingly. The current control module 8 adjusts the magnitude and direction of the current passing through the coil 4 according to the control strategy, thereby generating the required damping force or equivalent negative stiffness, and realizing the adaptive adjustment of the vibration isolator stiffness and damping.

[0032] The variable stiffness and damping control unit adopts the following stiffness and damping control strategy based on the vibration source frequency (excitation frequency) f and the system's initial natural frequency f0. When the ratio of the excitation frequency f to the system's natural frequency f0 is ≤ 1, the variable stiffness and damping control unit forces the Ampere force on the energized coil in the magnetic field to be opposite to the vibration source's direction. This adaptively introduces the required nonlinear electromagnetic damping, minimizing the unbalanced force acting on the load platform. When 1 < f / f0 ≤ √2, the variable stiffness and damping control unit forces the Ampere force on the energized coil in the magnetic field to be aligned with the vibration source's direction. This adaptively introduces the required nonlinear negative stiffness. In this case, 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 isolation unit) is maximized. When f / f0 > √2, the variable stiffness and damping control unit forces the Ampere force on the energized coil in the magnetic field to be aligned with the vibration source's direction. This adaptively introduces the required nonlinear negative stiffness, minimizing the damping of the entire system.

[0033] In a specific implementation process, the cross-sectional shape of the vibration isolator of the present invention can be circular, square or other shapes.

[0034] 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 scope of protection of the present invention.

Claims

1. An electromagnetic variable stiffness and variable damping vibration isolator, characterized in that It includes a load platform, vibration isolation elements, a coil wound around a cylinder, permanent magnets, a base, and a variable stiffness and variable damping control unit; the vibration isolation elements are arranged on the base to support the load platform, the cylinder is fixed to the bottom of the load platform, and the permanent magnets are arranged on the base and located outside the coil; The variable stiffness and variable damping control unit includes a main control board, a current control module, and a vibration sensor; the vibration sensor is fixed on the load platform, the main control board is electrically connected to the vibration sensor and the current control module respectively, the main control board analyzes the vibration direction, exciting force magnitude, and frequency information of the load platform based on the vibration signal sensed by the vibration sensor, determines the stiffness and damping control strategies of the vibration isolator, and the current control module adjusts the magnitude and direction of the coil energizing current according to the control strategies, thereby generating the required damping force or equivalent negative stiffness to achieve the adaptive adjustment of the stiffness and damping of the vibration isolator; According to the vibration frequency of the vibration source f and the initial natural frequency of the system f 0, the following stiffness and damping control strategies are adopted: When the vibration frequency of the vibration source f is less than or equal to 1 times the natural frequency of the system f 0, the variable stiffness and variable damping control unit makes the direction of the Ampere force on the energized coil in the magnetic field opposite to the vibration direction of the vibration source. Thus, the system adaptively introduces the required non-linear electromagnetic damping to cancel the unbalanced force acting on the load platform with the electromagnetic damping force; when 1 < f / f 0 ≤ , the variable stiffness and variable damping control unit makes the direction of the Ampere force on the energized coil in the magnetic field the same as the vibration direction of the vibration source. Thus, the system adaptively introduces the required non-linear negative stiffness. At this time, the electromagnetic damping is zero, but there is non-electromagnetic damping in the system; when f / f 0 > , the variable stiffness and variable damping control unit makes the direction of the Ampere force on the energized coil in the magnetic field the same as the vibration direction of the vibration source. Thus, the system adaptively introduces the required non-linear negative stiffness.

2. The electromagnetic variable stiffness and variable damping vibration isolator according to claim 1, characterized in that, The number of the permanent magnets is one pair or multiple pairs.

3. The electromagnetic variable stiffness and variable damping vibration isolator according to claim 1, wherein, The cylinder is made of non-magnetic material.

4. The electromagnetic variable stiffness and variable damping vibration isolator according to claim 3, characterized in that The material of the cylinder is aluminum alloy or ceramic.

5. The electromagnetic variable stiffness and variable damping vibration isolator according to claim 1, characterized in that The vibration isolation elements are steel springs, air springs, or rubber vibration isolation pads.

6. The electromagnetic variable stiffness and variable damping vibration isolator according to claim 1, wherein Limiters for fixing the vibration isolation elements are arranged at both ends of the vibration isolation elements.

7. The electromagnetic variable stiffness and variable damping vibration isolator according to claim 1, characterized in that, One or more vibration isolation elements are arranged.

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