CN117471562A - Vibration isolation system and relative gravity meter - Google Patents

Abstract

This application relates to a vibration isolation system and a relative gravity meter. The vibration isolation system includes: a base, a pendulum and a magnetic levitation device. The magnetic levitation device includes two first magnets and two second magnets. The vibration isolation system of the present application uses the uniform magnetic field generated by each first magnet to cause the second magnet to receive equal force everywhere in the uniform magnetic field, thus achieving approximately zero stiffness. Moreover, the static magnetic force generated by each first magnet on the second magnet can balance the effective load of the second magnet and the pendulum, thereby solving the contradiction between load and vibration isolation, that is, the larger the load, the weaker the vibration isolation effect.

Description

Vibration isolation system and relative gravity meter

Technical field

This application relates to the field of measurement technology, and in particular to a vibration isolation system and a relative gravimeter.

Background technique

The acceleration of gravity is an important physical quantity in astrophysics and celestial mechanics. It is of great significance to understanding the origin and evolution of the universe, astrophysics, planetary science and other fields. In the process of measuring the acceleration of gravity, the gravity acceleration of the measuring point is generally obtained by measuring the displacement and time interval of the falling object relative to the reference prism when it is in free fall. During the measurement process, ground vibration will interfere with the reference prism, thus affecting the measurement accuracy.

In practical applications, a vibration isolation device with an elastic structure (such as a spring) with limited stiffness is usually used to reduce the interference of ground vibration on the reference prism when measuring gravity acceleration.

However, using elastic structures for vibration isolation has the problem of conflict between load and vibration isolation.

Contents of the invention

Based on this, it is necessary to provide a vibration isolation system and relative gravimeter that can solve the contradiction between load and vibration isolation in view of the above technical problems.

In a first aspect, the present application provides a vibration isolation system. The vibration isolation system includes: base, pendulum and magnetic levitation device;

The swing rod is connected to the base, and the swing rod is parallel to the base;

The magnetic levitation device includes two first magnets and second magnets. One first magnet is arranged on the side of the swing rod close to the base, and the other first magnet is arranged on the other side of the swing rod away from the base; the second magnet is arranged on The surface of the pendulum and located between the two first magnets;

A uniform magnetic field is formed between the two first magnets, and the magnetic field force generated by each first magnet against the second magnet is opposite to the gravity direction of the pendulum; the magnetic field force is used to balance the payload, and the payload includes the second magnet and the pendulum. Rod.

In one embodiment, the two first magnets have the same size, and the size of the two first magnets is larger than the size of the second magnet.

In one embodiment, the two first magnets have the same shape, and the two first magnets are any one of a ring magnet, a cylindrical magnet, and a wedge magnet.

In one embodiment, the second magnet is a cylindrical magnet.

In one embodiment, the above-mentioned vibration isolation system further includes a first coil, and the first coil is wound on the surface of the first magnet;

The first coil is used to generate a changing first magnetic field, and the first magnetic field is used to provide force to the second magnet.

In one embodiment, the above-mentioned vibration isolation system further includes a second coil, and the second coil is wound on the surface of the second magnet;

The second coil is used to generate a changing second magnetic field, and the second magnetic field is used to provide force to the second magnet.

In one embodiment, the second coil is a Helmholtz coil.

In one embodiment, the above-mentioned vibration isolation system also includes a displacement detection device and an adjustment device. The displacement detection device is disposed between the swing bar and the base. The adjustment device is disposed between the swing bar and the base. The displacement detection device is connected to the swing bar. Adjust device connections;

The displacement detection device is used to detect the displacement of the pendulum rod and transmit the displacement to the adjustment device;

The adjustment device is used to apply a compensating force to the pendulum bar according to the displacement, and the compensation force is used to move the pendulum bar to a balanced position.

In one embodiment, the vibration isolation adjustment device includes a voice coil motor.

In one embodiment, the above-mentioned vibration isolation system further includes a filter circuit, the input end of the filter circuit is connected to the displacement detection device, and the output end of the filter circuit is connected to the adjustment device.

In one embodiment, the above-mentioned vibration isolation system further includes a flexible connector, which is disposed between the swing bar and the base and used to connect the swing bar and the base.

In one embodiment, the flexible connector includes a flexible hinge.

In a second aspect, this application also provides a relative gravimeter. The relative gravimeter includes: a reference prism and the vibration isolation system of the first aspect; the reference prism is arranged on the pendulum in the vibration isolation system.

The above-mentioned vibration isolation system and relative gravimeter, the vibration isolation system includes: a base, a pendulum and a magnetic levitation device; the pendulum is connected to the base, and the pendulum is parallel to the base; the magnetic levitation device includes two first magnets and a second Magnets, a first magnet is disposed on the side of the swing bar close to the base, and another first magnet is disposed on the other side of the swing bar away from the base; the second magnet is disposed on the surface of the swing bar and is located between the two first magnets. between the magnets; a uniform magnetic field is formed between the two first magnets, and the magnetic field force generated by each first magnet against the second magnet is opposite to the gravity direction of the pendulum; the magnetic field force is used to balance the payload, and the payload includes the third Two magnets and swing rods. The vibration isolation system of the embodiment of the present application uses the uniform magnetic field generated by each first magnet, so that the force on the second magnet in the uniform magnetic field is equal everywhere, thereby achieving approximately zero stiffness. Moreover, the static magnetic force generated by each first magnet on the second magnet can balance the effective load of the second magnet and the pendulum, thereby solving the contradiction between load and vibration isolation, that is, the greater the load, the weaker the vibration isolation effect. .

Description of the drawings

Figure 1 is one of the schematic diagrams of vibration isolation based on approximately zero stiffness of permanent magnets in the related art;

Figure 2 is the second schematic diagram of vibration isolation based on approximately zero stiffness of permanent magnets in the related art;

Figure 3 is a schematic diagram of an approximately zero-stiffness system based on annular permanent magnets in the related art;

Figure 4 is a schematic diagram of a vibration isolation system in one embodiment;

Figure 5 is a schematic diagram of a vibration isolation system in another embodiment;

Figure 6 is a schematic diagram of a relative gravimeter in one embodiment.

Reference signs:

Vibration isolation device: vibration isolation system 1; relative gravity meter 2; base 11; pendulum 12; magnetic levitation device 13; counterweight 14; displacement detection module 15; adjustment module 16; flexible connector 17; reference prism 18; first Magnet 131; second magnet 132; reflector 151; beam splitter 151; photodetector 153; laser 154; voice coil motor 161.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

In the description of this application, it should be understood that if the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", " "Front", "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axis", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating Or it is implied that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be construed as a limitation on the present application.

In addition, in the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

In this application, unless otherwise expressly stated and limited, if the terms "installation", "connection", "connection", "fixing", etc. appear, these terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection, or it can be integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. or the interaction between two elements, unless otherwise expressly limited. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In this application, unless otherwise explicitly stated and limited, if a first feature is "on" or "below" a second feature or similar descriptions, the meaning may be that the first and second features are in direct contact, or The first and second characteristics are in indirect contact through an intermediary. Furthermore, the terms "above", "above" and "above" the first feature is above the second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "below" and "beneath" the first feature to the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature has a smaller horizontal height than the second feature.

It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. If an element is said to be "connected" to another element, it can be directly connected to the other element or there may also be intervening elements present. If present, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and are not meant to be exclusive. implementation.

First, before introducing the technical solutions of the embodiments of the present application in detail, the technical background on which the embodiments of the present application are based will be introduced.

In the process of measuring the acceleration of gravity, ground vibration will interfere with the reference prism, thus affecting the measurement accuracy. The ultra-low frequency vertical vibration isolation system can reduce the impact of ground vibration on the reference prism and provide an inertial reference point for the system.

As shown in Figure 1, in terms of achieving vibration isolation based on the approximately zero stiffness of permanent magnets, pairs of permanent magnets have been used to achieve vibration isolation with six degrees of freedom. Two upper and lower annular magnets are used to construct a magnetic field with a uniform central gradient, such as As shown in Figure 2, there is an area with an approximate slope of zero in the middle of the central magnet where the force is applied. The experimental and theoretical resonant frequencies of the system in the X, Y, and Z directions are approximately 2.9Hz, 3Hz, 1.8Hz and 3Hz, 3Hz, and 1.6Hz respectively. However, this technology has the problem that the cycle is not long enough.

The approximately zero-stiffness system based on annular permanent magnets is shown in Figure 3. The principle is to use two axially magnetized magnetic rings to generate negative stiffness. The final vibration isolation frequency of this system is about 15Hz. The vibration isolation frequency of this system is too high, and elastic materials are used for vibration isolation. The design conflict between load-bearing capacity and vibration isolation performance results in a short period of the vibration isolation system.

In addition, linear electromagnetic springs and linear springs are also used to achieve quasi-zero stiffness. Linear electromagnetic springs (LES) are connected in parallel with traditional linear isolation systems. LES can generate linear negative stiffness to balance the positive stiffness of traditional systems. The natural frequency can be obtained from Adjust 10Hz to the lowest 2Hz. This system uses elastic materials for vibration isolation, and there is a contradiction between stiffness and load.

It can be seen from the above related technologies that in traditional passive vibration isolation devices, limited stiffness elastic structures are often used, which requires complex geometric structures to solve the design contradiction between load-bearing capacity and vibration isolation performance. At the same time, there are also deficiencies in temperature characteristics. .

Based on this, this application provides a vibration isolation system and a relative gravity meter, aiming to solve the above technical problems.

In one embodiment, as shown in FIG. 4 , a vibration isolation system 1 is provided. The vibration isolation system 1 includes: a base 11 , a pendulum 12 and a magnetic levitation device 13 .

The swing bar 12 and the base 11 are connected. Optionally, the swing bar 12 and the base 11 can be connected through hinges, rivets, or bearings. The embodiment of the present application describes the connection method between the swing bar 12 and the base 11 No specific restrictions are made. The swing bar 12 is arranged transversely and remains parallel to the base 11 and the ground. At the same time, the swing rod 12 can be stacked with springs to increase the positive stiffness.

The magnetic levitation device 13 includes two first magnets 131 and second magnets 132 . Among them, the first magnet 131 and the second magnet 132 in the embodiment of the present application are permanent magnets. The first magnet 131 may include one of a ring magnet, a cylindrical magnet, and a wedge magnet. The second magnet 132 may include a circular magnet or a cylindrical magnet.

Among them, one first magnet 131 is disposed on the side of the swing bar 12 close to the base 11 , and the other first magnet 131 is disposed on the other side of the swing bar 12 away from the base 11 . That is, one of the first magnets 131 is above the second magnet 132 and the other first magnet 131 is below the second magnet 132 . The first magnet 131 may be supported on the ground by pillars. This application does not specifically limit the number of columns. The second magnet 132 is disposed on the surface of the swing bar 12 and is located between the two first magnets 131 . The spacing can also be adjusted by adding or reducing spacers between the pillars and the upper and lower bases to adjust the stress range and instrument stiffness. In the magnetic field of this structure, especially in the working range, the force has good linearity.

The two first magnets 131 are used to form a uniform magnetic field, so that the force received by the second magnet 132 in the uniform magnetic field is equal everywhere. Moreover, the magnetic field force generated by each first magnet 131 against the second magnet 132 is opposite to the direction of gravity of the swing rod 12 .

Optionally, the N level of the first magnet 131 above the second magnet 132 is facing upwards and the S level is facing downward, the N level of the first magnet 131 below the second magnet 132 is facing downwards, and the S level is facing upwards, and the second level in the middle is facing upwards. The N stage of the magnet 132 faces upward and the S stage faces downward, so that the first magnet 131 and the second magnet 132 above have the same polarization and generate an attractive force on the second magnet 132 . The first magnet 131 below has an opposite magnetization direction to the second magnet 132 and generates a repulsive force on the second magnet 132, thus giving an upward force to the second magnet 132.

According to the formula for the force exerted on a magnetic dipole (the second magnet 132 in this embodiment) in a magnetic field, it can be known that in a magnetic field with a uniform gradient, the force exerted on the magnetic dipole is equal everywhere. In this magnetic field, a second magnet 132 is placed so that the magnetic force it receives in the magnetic field is balanced with itself, the pendulum 12 and the required devices, that is, the equivalent restoring force is zero everywhere.

The above-mentioned vibration isolation system includes a base, a pendulum and a magnetic levitation device. The swing rod is connected to the base, and the swing rod is parallel to the base. The magnetic levitation device includes two first magnets and second magnets. One first magnet is arranged on the side of the swing rod close to the base, and the other first magnet is arranged on the other side of the swing rod away from the base; the second magnet is arranged on The surface of the pendulum and is located between the two first magnets. A uniform magnetic field is formed between the two first magnets, and the magnetic field force generated by each first magnet against the second magnet is opposite to the gravity direction of the pendulum. Magnetic field forces are used to balance the payload, which consists of a second magnet and a pendulum. The vibration isolation system of the embodiment of the present application uses the uniform magnetic field generated by each first magnet, so that the force on the second magnet in the uniform magnetic field is equal everywhere, thereby achieving approximately zero stiffness. Moreover, the static magnetic force generated by each first magnet on the second magnet can balance the effective load of the second magnet and the pendulum, thereby solving the contradiction between load and vibration isolation, that is, the greater the load, the weaker the vibration isolation effect. .

In another embodiment, based on the above embodiment, the two first magnets 131 have the same size, and the size of the two first magnets 131 is larger than the size of the second magnet 132 .

In the embodiment of the present application, the first magnet 131 is set to a larger size, and the second magnet 132 is set to a smaller size. This is to make the first magnet 131 generate a larger magnetic field force, thereby balancing the gravity of the second magnet 132 , the swing bar 12 and the counterweight 14 . The specific sizes of the first magnet 131 and the second magnet 132 are determined by actual needs.

In the above vibration isolation system, the two first magnets have the same size, so that the first magnet can generate a magnetic field with a uniform gradient, so that the second magnet is equal everywhere, thereby achieving approximately zero stiffness and effectively extending the vibration isolation period. Setting the size of the two first magnets to be larger than the size of the second magnet allows the first magnets to generate a magnetic field force that can balance the gravity of the second magnet, the pendulum and the counterweight.

In one embodiment, the shapes of the two first magnets 131 are the same, and the two first magnets 131 are any one of a ring magnet, a cylindrical magnet, and a wedge magnet.

In the embodiment of the present application, since the first magnet 131 is a permanent magnet, it can be known theoretically that the permanent magnet can generate a uniform magnetic field. Arranging two first magnets 131 with the same shape together can generate a magnetic field with a uniform gradient. The first magnet 131 may have various shapes, including any one of a ring magnet, a cylindrical magnet, and a wedge magnet. The specific shape of the first magnet 131 to be used is determined by actual needs.

In the above-mentioned vibration isolation system 1, the two first magnets 131 are set to have the same shape, so that the first magnet 131 generates a magnetic field with a uniform gradient, so that the second magnet 132 in it is equal everywhere, thereby achieving approximately zero stiffness and effectively extending the Isolation period.

In another embodiment, the type of the first magnet 131 can be selected from a variety of options to ensure high applicability.

In one embodiment, the above-mentioned vibration isolation system 1 further includes a first coil, and the first coil is wound on the surface of the first magnet 131 .

In the embodiment of the present application, the first coil includes but is not limited to a Helmholtz coil, a saddle coil, etc., and is a coil capable of generating a uniform magnetic field. The resulting uniform magnetic field is the first magnetic field that can produce changes. The first coil can be wound on the surface of the first magnet 131 or on any one of the two second magnets 132, which is not specifically limited in the embodiment of the present application.

The above-mentioned vibration isolation system 1 also includes a first coil. The first coil can generate a first magnetic field with uniform intensity. The first coil is wound on the surface of the first magnet 131. The first magnetic field can provide force to the second magnet 132. This allows the second magnet 132 to obtain a better force curve.

In one embodiment, the above-mentioned vibration isolation system 1 further includes a second coil, and the second coil is wound on the surface of the second magnet 132 .

The second coil includes but is not limited to a Helmholtz coil, a saddle coil, etc., and is a coil capable of generating a uniform magnetic field. The resulting uniform magnetic field can produce a varying second magnetic field. The second coil may be wound around the first magnet 131 . Optionally, second coils can be wound around both first magnets.

The above-mentioned vibration isolation system also includes a second coil. The second coil can generate a second magnetic field with uniform intensity. The second coil is wound on the surface of the second magnet. The second magnetic field can provide force to the first magnet, which can make the second magnet The second magnet obtains a better force curve.

In another embodiment, the second coil is a Helmholtz coil.

Among them, the Helmholtz coil is used to generate the magnetic field of the device in an almost uniform area, which can produce an area where the magnetic field strength is closer to zero.

As shown in FIG. 5 , it can be seen that the change in force of the second magnet 132 in a long interval is at a very small level, so it can basically meet the vibration isolation requirements. Helmholtz coils can be added to the upper and lower first magnets 131 or the second magnets 132 to obtain a better force curve or to compensate. If a Helmholtz coil is used to fine-tune the magnetic field when the second magnet 132 is off-center, the force at the off-center position can be closer to the force at the center position, that is, the working range can be expanded and better force can be obtained. curve. At the same time, the coil wound on the first magnet 131 can also be energized, and the current passing through the coil can be controlled by feedback to generate a changing magnetic field, and the force of the second magnet 132 can be fine-tuned to compensate.

In the above vibration isolation system, setting the second coil as a Helmholtz coil can allow the second magnet to obtain a better force curve or perform compensation, thereby further improving the vibration isolation capability of the vibration isolation system.

In another embodiment, as shown in FIG. 6 , the above-mentioned vibration isolation system 1 further includes a displacement detection device 15 and an adjustment device 16 .

In the embodiment of the present application, the displacement detection device 15 is a photoelectric detection circuit and is disposed between the swing rod 12 and the base 11 . The photodetection circuit includes a reflector 151, a beam splitter 152, a photodetector 153, and a laser 154. The reflector 151 is disposed below the swing rod 12. A spectroscope 152 and a four-quadrant photodetector 153 are disposed directly below the reflector 151. The four-quadrant photodetector 153 is disposed on the base 11. The spectroscope 152 is disposed on the four-quadrant photoelectric detector. On detector 153. The laser 154 is provided on one side of the photodetector 153 . The displacement detection device 15 is used to detect the displacement of the swing rod 12 and transmit the displacement to the adjustment device 16 . The adjustment device 16 is used to apply a compensation force to the fork bar 12 according to the displacement, and the compensation force is used to move the fork bar 12 to a balanced position.

Optionally, the detector is a four-quadrant photoelectric detector, which can accurately measure the motion state of the object.

Specifically, the laser 154 outputs detection light, passes through the dichroic mirror 152 to the reflector 151, and then the detection light passes through the reflector 151 and hits the four-quadrant photodetector 153. In this way, if the swing rod 12 swings, the four-quadrant photodetector 153 The detection light on the sensor will move, and the swing displacement of the pendulum rod 12 can be calculated through the output of the four-quadrant photodetector 153. Then the photodetector 153 transmits the swinging displacement of the swing rod 12 to the adjustment device 16 . The adjusting device 16 applies a compensating force to the fork bar 12 according to the displacement, so that the fork bar 12 moves to a balanced position.

The above-mentioned vibration isolation system also includes a displacement detection device and an adjustment device. According to the four-quadrant photoelectric detector in the displacement detection device, the displacement of the pendulum rod can be accurately calculated, so that the adjustment device can adjust the pendulum rod according to the displacement of the pendulum rod to compensate. The drift of the vibration isolation system further improves the vibration isolation capability of the vibration isolation system.

In another embodiment, continuing to refer to FIG. 6 , the vibration isolation adjustment device 16 includes a voice coil motor 161 .

Among them, the voice coil motor 161 is a special form of direct drive motor. It has the characteristics of simple structure, small size, high speed and fast response. The working principle is that when an energized coil (conductor) is placed in a magnetic field, a force is generated, where the magnitude of the force is proportional to the current applied to the coil.

In the embodiment of the present application, the vibration isolation adjustment device 16 uses a voice coil motor 161, which can generate a corresponding force according to the displacement when receiving the displacement of the pendulum bar 12 output by the four-quadrant photodetector 153, and apply it to the pendulum bar 12 .

In the above-mentioned vibration isolation system, the vibration isolation adjustment device uses a voice coil motor, which has the characteristics of simple structure, small size, high speed, and fast response. It can quickly adjust the displacement of the pendulum bar 12 by generating a corresponding force through the displacement of the pendulum bar.

In another embodiment, the above-mentioned vibration isolation system 1 further includes a filter circuit, the input end of the filter circuit is connected to the displacement detection device 15 , and the output end of the filter circuit is connected to the adjustment device 16 .

Among them, the filter circuit includes a PI (Power Integrity) circuit, and the PI circuit is connected to the photoelectric detection circuit and the voice coil motor 161 respectively.

In the embodiment of the present application, the PI circuit filters and amplifies the received displacement signal sent by the displacement detection device 15 , and then transmits it to the voice coil motor 161 .

The above-mentioned vibration isolation system also includes a filter circuit. The filter circuit can filter and amplify the received displacement signal, thereby making the displacement signal received by the voice coil motor more accurate.

In another embodiment, continuing to refer to FIG. 6 , the above-mentioned vibration isolation system 1 also includes a flexible connector 17 . The flexible connector 17 is disposed between the swing bar 12 and the base 11 for connecting the swing bar 12 and the base. Seat 11.

The flexible connector 17 can be a hinge connection, a snap ring connection, a spring connection, etc. The flexible connector 17 can connect the swing bar 12 and the base 11 so that the swing bar 12 can move vertically.

In the above-mentioned vibration isolation system, a flexible connector is arranged between the pendulum rod and the base, which can limit the pendulum rod to only move in one dimension, thereby limiting the system to only one degree of freedom in the vertical direction, which can reduce some of the problems caused by other degrees of freedom. error.

In another embodiment, continuing to refer to FIG. 6 , the above-mentioned flexible connector 17 includes a flexible hinge.

Among them, the flexible hinge is an elastic support with a simple structure and a relatively regular shape. It has a center of rotation that coincides with the geometric central axis and works by relying on the limited deformation of elastic sheets evenly distributed in the radial direction of the circumference. Under torsional load, rotational motion occurs within a limited angular range around its center of rotation.

The flexible connector 17 in the embodiment of the present application adopts a flexible hinge, and the swing bar 12 can be connected to the base 11 through the flexible hinge, so that the swing bar 12 can move in the vertical direction.

In the above-mentioned vibration isolation system, the flexible connector adopts a flexible hinge, that is, a flexible hinge is used to connect the swing bar and the base. This ensures that there is no mechanical friction between the swing bar and the base during the rotation process, so that the balance process is stable. System errors can be reduced.

In a second aspect, embodiments of the present application also provide a relative gravimeter 2 . Continuing to refer to Figure 6, the relative gravimeter 2 includes: a reference prism 18 and the vibration isolation system 1 of the first aspect; the vibration isolation system 1, as shown in Figure 6, includes: a base 11, a pendulum 12 and a magnetic levitation Device 13; the swing bar 12 is connected to the base 11, and the swing bar 12 is parallel to the base 11; the magnetic levitation device 13 includes two first magnets 131 and second magnets 132, and a first magnet 131 is arranged on the swing bar 12 close to the base. On one side of the base 11, another first magnet 131 is disposed on the other side of the swing bar 12 away from the base 11; a second magnet 132 is disposed on the surface of the swing bar 12 and is located between the two first magnets 131; A uniform magnetic field is formed between the first magnets 131, and the magnetic field force generated by each first magnet 131 against the second magnet 132 is opposite to the gravity direction of the pendulum 12; the magnetic field force is used to balance the payload, and the payload includes the second Magnet 132 and pendulum 12. The reference prism 18 is provided on the swing bar 12 in the vibration isolation system 1 .

The above-mentioned relative gravimeter includes a reference prism and a vibration isolation system. The vibration isolation system in the embodiment of the present application uses the uniform magnetic field generated by each first magnet to make the force on the second magnet in the uniform magnetic field equal everywhere, thereby achieving approximately zero Stiffness. Moreover, the static magnetic force generated by each first magnet on the second magnet can balance the effective load of the second magnet and the pendulum, thereby solving the contradiction between load and vibration isolation, that is, the greater the load, the weaker the vibration isolation effect. . At the same time, by using the vibration isolation system of the present application to isolate the reference prism, the impact on the stability of the reference prism can be reduced when the ground vibrates, thereby ensuring the measurement accuracy of the relative gravimeter.

The technical features of the above embodiments can be combined in any way. To simplify the description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, all possible combinations should be used. It is considered to be within the scope of this manual.

The above-described embodiments only express several implementation modes of the present application, and their descriptions are relatively specific and detailed, but should not be construed as limiting the patent scope of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims (13)

1. A vibration isolation system, characterized in that the vibration isolation system includes: a base, a pendulum and a magnetic levitation device; The swing bar is connected to the base, and the swing bar is parallel to the base; The magnetic levitation device includes two first magnets and a second magnet. One of the first magnets is disposed on the side of the swing bar close to the base, and the other first magnet is disposed on the side of the swing bar away from the base. The other side of the base; the second magnet is arranged on the surface of the swing bar and is located between the two first magnets; A uniform magnetic field is formed between the two first magnets, and the magnetic field force generated by each first magnet against the second magnet is opposite to the direction of gravity of the pendulum; the magnetic field force is used to effectively balance The payload includes the second magnet and the swing rod. 2. The vibration isolation system according to claim 1, wherein the two first magnets have the same size, and the size of the two first magnets is larger than the size of the second magnet. 3. The vibration isolation system according to claim 1, wherein the two first magnets have the same shape, and the two first magnets are any one of a ring magnet, a cylindrical magnet and a wedge magnet. kind. 4. The vibration isolation system according to claim 1, wherein the second magnet is a cylindrical magnet. 5. The vibration isolation system according to any one of claims 1 to 4, characterized in that the vibration isolation system further includes a first coil, and the first coil is wound on the surface of the first magnet; The first coil is used to generate a changing first magnetic field, and the first magnetic field is used to provide force to the second magnet. 6. The vibration isolation system according to any one of claims 1 to 4, characterized in that the vibration isolation system further includes a second coil, and the second coil is wound on the surface of the second magnet; The second coil is used to generate a changing second magnetic field, and the second magnetic field is used to provide force to the second magnet. 7. The vibration isolation system according to claim 6, wherein the second coil is a Helmholtz coil. 8. The vibration isolation system according to any one of claims 1 to 4, characterized in that the vibration isolation system further includes a displacement detection device and an adjustment device, the displacement detection device is disposed between the swing bar and the Between the bases, the adjustment device is provided between the swing bar and the base, and the displacement detection device is connected to the adjustment device; The displacement detection device is used to detect the displacement of the swing rod and transmit the displacement to the adjustment device; The adjustment device is used to apply a compensation force to the swing bar according to the displacement, and the compensation force is used to move the swing bar to a balanced position. 9. The vibration isolation system of claim 8, wherein the adjustment device includes a voice coil motor. 10. The vibration isolation system according to claim 8, characterized in that the vibration isolation system further includes a filter circuit, the input end of the filter circuit is connected to the displacement detection device, and the output end of the filter circuit is connected to the displacement detection device. The adjustment device is connected. 11. The vibration isolation system according to any one of claims 1 to 4, characterized in that the vibration isolation system further includes a flexible connector, and the flexible connector is disposed between the swing bar and the base. space for connecting the swing rod and the base. 12. The vibration isolation system of claim 11, wherein the flexible connector includes a flexible hinge. 13. A relative gravimeter, characterized in that the relative gravimeter includes: a reference prism and the vibration isolation system according to any one of claims 1-12; The reference prism is arranged on the pendulum in the vibration isolation system.