阅读说明：本技术 一种模拟空间目标电磁-涡流消旋的地面试验系统 (Ground test system for simulating despinning of space target electromagnetism-vortex ) 是由 黄涣 杨乐平 张元文 蔡伟伟 于 2020-04-15 设计创作，主要内容包括：一种模拟空间目标电磁-涡流消旋的地面试验系统,包括电磁场发生装置、真空容器、旋转机构以及空间目标模拟件。空间目标模拟件设置在真空容器中,真空容器侧边设置有电磁场发生装置；旋转机构包括喷气机构、风叶轮以及高精度空气轴承,空间目标模拟件通过其底部的定位锥与高精度空气轴承固定连接,喷气机构喷气带动高精度空气轴承底部中心的风叶轮,进而带动空间目标模拟件旋转,模拟在真空环境中自由旋转的空间目标。电磁场发生装置由高温超导材料构成,可实现更大可控场强,伺服导轨与伺服转台可模拟与目标的相对运动状态。本发明可实现可控大场强电磁场生成与目标长时间自由旋转状态的有效模拟,适合开展空间目标的电磁-涡流消旋试验验证。(A ground test system for simulating despinning of space target electromagnetism-eddy current comprises an electromagnetic field generating device, a vacuum container, a rotating mechanism and a space target simulation piece. The space target simulation piece is arranged in a vacuum container, and an electromagnetic field generating device is arranged on the side edge of the vacuum container; the rotating mechanism comprises an air injection mechanism, a fan blade wheel and a high-precision air bearing, the space target simulation piece is fixedly connected with the high-precision air bearing through a positioning cone at the bottom of the space target simulation piece, the air injection mechanism injects air to drive the fan blade wheel at the center of the bottom of the high-precision air bearing, and then the space target simulation piece is driven to rotate to simulate a space target which freely rotates in a vacuum environment. The electromagnetic field generating device is made of high-temperature superconducting materials, and can realize larger controllable field intensity, and the servo guide rail and the servo turntable can simulate the relative motion state with a target. The invention can realize the generation of controllable large-field-intensity electromagnetic field and the effective simulation of the long-time free rotation state of the target, and is suitable for developing the electromagnetic-eddy current racemization test verification of the space target.)

1. A ground test system for simulating space target electromagnetic-eddy current despinning is characterized in that: the space target simulation piece is arranged in the vacuum container, and an electromagnetic field generating device is arranged on the side edge of the vacuum container and used for generating an electromagnetic field; the rotating mechanism comprises an air injection mechanism, a fan blade wheel and a high-precision air bearing, a positioning cone is arranged at the bottom of the space target simulation piece, the positioning cone is connected with the high-precision air bearing so as to realize the fixed connection of the space target simulation piece and the high-precision air bearing, the fan blade wheel is installed at the center of the bottom of the high-precision air bearing, the air injection mechanism is arranged on the side edge of the fan blade wheel, an air nozzle of the air injection mechanism is aligned with the fan blade wheel, the fan blade wheel is driven by air injection of the air nozzle to rotate, the space target simulation piece fixedly connected with the high-precision air bearing is driven to start rotating, and a space target.

2. The ground test system for simulating space target electromagnetic-eddy current racemization of claim 1, wherein: the electromagnetic field generating device comprises an electromagnetic actuator, a servo turntable, a turntable support and a servo guide rail, wherein the electromagnetic actuator is fixed on the servo turntable, and the servo turntable is used for realizing the rotation control of the electromagnetic actuator; the servo turntable is arranged above the servo guide rail through the turntable support, and the turntable support can move along the guide rail direction of the servo guide rail so as to drive the electromagnetic actuator to realize linear motion control.

3. The ground test system for simulating the racemization of electromagnetic-eddy currents of a space target according to claim 1 or 2, wherein: the electromagnetic actuator is an electromagnetic coil wound on the basis of a high-temperature superconducting material.

4. The ground test system for simulating space target electromagnetic-eddy current racemization of claim 1, wherein: the vacuum container comprises a vacuum cover body and a tower-type multilayer cover plate, and the top surface of the vacuum cover body is sealed by the tower-type multilayer cover plate.

5. The ground test system for simulating space target electromagnetic-eddy current racemization of claim 4, wherein: the tower-type multilayer cover plate comprises a plurality of layers of cover plates and self-locking bolts, the plurality of layers of cover plates are stacked in a tower type, and the plurality of layers of cover plates are fastened together through the self-locking bolts in the center; the bottom of the vacuum cover body is arranged on a sealing groove correspondingly formed on the mounting platform, and an EPDM rubber sealing strip is arranged in the sealing groove.

6. The ground test system for simulating space target electromagnetic-eddy current racemization of claim 1, wherein: the mounting platform is provided with a mounting through hole for mounting the high-precision air bearing, and the high-precision air bearing is mounted in the mounting platform; the space target simulation piece is fixedly connected with the positioning cone along the axis, the positioning cone is vertically inserted into a cone sleeve of the high-precision air bearing, and the positioning cone and the high-precision air bearing are fixed in the vertical direction through a cone sleeve locking mechanism.

7. The ground test system for simulating space target electromagnetic-eddy current racemization of claim 1, wherein: the mounting platform is a marble platform, and an air exhaust hole is formed in the marble platform to realize the vacuum pumping of the space in the vacuum cover body; a dynamic seal air leakage port is arranged between the high-precision air bearing and the marble platform, and air is discharged through the dynamic seal air leakage port after the high-precision air bearing is ventilated;

the mounting platform is located the top of rotary platform support, has laid a plurality of level fine setting pieces between mounting platform and the rotary platform support, adjusts the mounting platform level through a plurality of level fine setting pieces.

8. The ground test system for simulating space target electromagnetic-eddy current racemization of claim 1, wherein: the air nozzle of the air injection mechanism comprises a left spinning air nozzle and a right spinning air nozzle, the left spinning air nozzle and the right spinning air nozzle are parallelly installed on the air injection support and are respectively arranged on the left side and the right side of the air impeller, and the left spinning air nozzle and the right spinning air nozzle inject air to the air impeller, so that the space target simulation piece slowly spins to simulate a space target freely rotating in a vacuum environment.

9. The ground test system for simulating space target electromagnetic-eddy current racemization of claim 1, wherein: the laser rotating speed meter is aligned to the black and white division marks on the blades of the wind impeller and used for measuring the real-time rotating speed of the space target simulation piece.

10. A ground test method for simulating space target electromagnetic-eddy current racemization is characterized by comprising the following steps:

the method comprises the following steps: leveling a marble table provided with a high-precision air bearing by using a level bar, mounting a spatial target simulation piece, and secondarily leveling by using the level bar;

step two: slightly rotating the space target simulation piece, measuring the edge jump of the upper top of the space target simulation piece by a micrometer, ensuring that the coaxiality of the target is not more than 0.05mm in a rotating state, and then tightening a taper sleeve locking mechanism;

step three: placing a vacuum cover, and vacuumizing by using a vacuum pump until the vacuum degree required by the experimental design is reached; continuously vacuumizing by using a vacuum pump in the test process so as to maintain the vacuum degree all the time;

step four: starting the air injection mechanism, enabling the air injection nozzle to aim at the air impeller to inject air, slowly starting the space target simulation piece, stopping injecting air after the expected rotating speed is reached and stabilized, and measuring the rotating speed attenuation change of the space target simulation piece until the space target simulation piece stops rotating;

step five: the electromagnetic actuator is maneuvered to a preset relative position and posture, and is electrified to generate an electromagnetic field to reach the designed required magnetic field intensity; the air injection mechanism is restarted, the air injection nozzle aims at the air impeller to inject air, so that the space target simulation piece slowly starts rotating, and the air injection is stopped after the expected rotating speed of the step four is reached and stabilized; measuring the attenuation change of the rotating speed of the space target simulation piece until the space target simulation piece stops rotating;

step six: and comparing the measurement results of the step four and the step five, and analyzing to obtain the racemization capacity and action characteristic of the electromagnetic-eddy current.

Technical Field

The invention belongs to the technical field of space control and ground test simulation thereof, and particularly relates to a ground test system for simulating space target electromagnetism-vortex despinning.

Background

The current orbital debris, including failed satellites, occupies a significant portion of the space-consuming targets, not only occupies valuable orbital resources, but also presents a safety risk to other normal in-orbit spacecraft, requiring in-orbit servicing or active removal thereof by close range manipulation means. However, failed satellites are typically in a spinning state and due to long-term perturbation effects are accompanied by precession and nutation properties, with rotational speeds of up to nearly a hundred degrees per second. In order to ensure the smooth implementation of the subsequent control task, firstly, the attitude rotation of the failed satellite is an essential link.

Compared with contact despinning means such as mechanical arms, speed reduction brushes and space ropes, the non-contact despinning method represented by electromagnetic-eddy current becomes the first choice with better safety and convenience. However, because the racemization effect of the electromagnetic-eddy current is a weak (racemization torque is in the order of tens to hundreds mNm) and a long-time (hours to tens of hours) effect, when a physical simulation test is carried out on the ground, on one hand, a controllable electromagnetic field which meets the racemization requirement and has a sufficiently large field strength needs to be constructed, and on the other hand, the long-time free rotation state of a space target and the racemization braking effect under the electromagnetic-eddy current effect need to be simulated as much as possible. This presents a number of challenges for ground test system design.

For micro-friction platforms, magnetic levitation and air flotation are the main modes of current application. However, in the electromagnetic-eddy current racemization test of a rotating target, the magnetic field action of magnetic suspension can generate interference on an electromagnetic field, and air floatation also needs to select a high-precision air floatation means to avoid annihilating the electromagnetic racemization action by air floatation friction, and the ambient atmosphere friction resistance needs to be effectively reduced in order to realize long-time uncontrolled rotation of the target. In addition, for the electromagnetic field generating device, the magnetic field intensity generated by the conventional normally conductive coil is limited, and the permanent magnet cannot realize flexible control of the magnetic field, so that the design based on the high-temperature superconducting material is necessary. At present, relevant patents aiming at target racemization test simulation, an electromagnetic racemization force test platform and the like are formed, and the comprehensive design has certain reference significance, but the two factors cannot be considered completely, and the physical characteristics of electromagnetic-eddy racemization need to be considered completely for comprehensive design.

Disclosure of Invention

The invention provides a ground test system for simulating racemization of space target electromagnetism-eddy current, aiming at solving the problem that the existing test system and platform can not give consideration to generation of controllable high-field-intensity electromagnetic field and long-time micro-friction free rotation state simulation.

In order to achieve the technical purpose, the invention adopts the following specific technical scheme:

a ground test system for simulating despinning of space target electromagnetism-eddy current comprises an electromagnetic field generating device, a vacuum container, a rotating mechanism and a space target simulation piece, wherein the space target simulation piece is arranged in the vacuum container, and the side edge of the vacuum container is provided with the electromagnetic field generating device to generate an electromagnetic field; the rotating mechanism comprises an air injection mechanism, a fan blade wheel and a high-precision air bearing, a positioning cone is arranged at the bottom of the space target simulation piece, the positioning cone is connected with the high-precision air bearing so as to realize the fixed connection of the space target simulation piece and the high-precision air bearing, the fan blade wheel is installed at the center of the bottom of the high-precision air bearing, the air injection mechanism is arranged on the side edge of the fan blade wheel, an air nozzle of the air injection mechanism is aligned with the fan blade wheel, the fan blade wheel is driven by air injection of the air nozzle to rotate, the space target simulation piece fixedly connected with the high-precision air bearing is driven to start rotating, and a space target.

As a preferable scheme of the present invention, the electromagnetic field generating device includes an electromagnetic actuator, a servo turntable, a turntable support, and a servo guide rail, the electromagnetic actuator is fixed to the servo turntable, and the servo turntable controls the rotation of the electromagnetic actuator. The servo turntable is arranged above the servo guide rail through the turntable support, and the turntable support can move along the guide rail direction of the servo guide rail so as to drive the electromagnetic actuator to realize linear motion control.

In a preferred embodiment of the present invention, the vacuum container includes a vacuum enclosure and a tower-type multi-layer cover plate, and the top surface of the vacuum enclosure is sealed by the tower-type multi-layer cover plate. Further, the tower-type multilayer cover plate comprises a plurality of layers of cover plates and self-locking bolts, the plurality of layers of cover plates are stacked in a tower type, and the plurality of layers of cover plates are fastened together through the self-locking bolts in the center. The bottom of the vacuum cover body is arranged in a sealing groove correspondingly formed in the mounting platform, wherein an EPDM rubber sealing strip is arranged in the sealing groove. Furthermore, an installation through hole for installing the high-precision air bearing is formed in the installation platform, and the high-precision air bearing is installed in the center of the installation platform. The space target simulation piece is fixedly connected with the positioning cone along the axis, the positioning cone is vertically inserted into a taper sleeve of the high-precision air bearing, and the positioning cone and the high-precision air bearing are fixed in the vertical direction through a taper sleeve locking mechanism. Be provided with the disappointing mouth of dynamic seal between high accuracy air bearing and the marble platform, the high accuracy air bearing back of ventilating, through the disappointing mouthful exhaust air of dynamic seal, make the air get into the internal space of vacuum cover as few as possible.

The mounting platform is located the top of rotary platform support, has laid a plurality of level fine setting pieces between mounting platform and the rotary platform support, adjusts the mounting platform level through a plurality of level fine setting pieces.

According to the preferable scheme of the invention, the air nozzle of the air injection mechanism comprises a left turning-off air nozzle and a right turning-off air nozzle, the left turning-off air nozzle and the right turning-off air nozzle are communicated with a high-pressure air source, and the left turning-off air nozzle and the right turning-off air nozzle are arranged on the air injection support in parallel and are respectively arranged at the left side and the right side of the air impeller. The left spinning air nozzle and the right spinning air nozzle spray air to the air impeller, so that the space target simulation piece slowly spins to simulate a space target freely rotating in a vacuum environment.

The invention further comprises a laser tachometer arranged on one side of the wind impeller, wherein black and white division marks are arranged on blades of the wind impeller, and the laser tachometer is aligned with the black and white division marks on the blades of the wind impeller and is used for measuring the real-time rotating speed of the space target simulation piece. The laser tachometer may be mounted in place on the rotating platform support.

As a preferable scheme of the present invention, the electromagnetic actuator is an electromagnetic coil wound based on a high-temperature superconducting material, and is provided with a cooling device for maintaining a low-temperature environment in which the superconducting coil operates, and a low-voltage large-current power supply is used for supplying power to the electromagnetic actuator, so that a larger controllable electromagnetic field can be generated under the same size of a normal-conductivity (material) coil.

As a preferable aspect of the present invention, the space target simulation member is an aluminum alloy structure and has a shape of a cylindrical shell or a spherical shell.

As a preferable scheme of the invention, the high-precision air bearing is a high-precision air bearing with an air-driven sealing structure, the axial bearing is more than or equal to 60kg, the radial bearing is more than or equal to 10kg, the radial rotation error is less than or equal to 1.0 mu m, the axial rotation error is less than or equal to 1.0 mu m, the coaxiality is less than or equal to 2.0 mu m, and the air supply pressure is 0.5-0.7 MPa. The vacuum degree of the pneumatic sealing structure is less than or equal to 100 Pa.

As a preferred scheme of the invention, the surface roundness of the positioning cone is less than or equal to 5 microns, the total runout of the conical surface is less than or equal to 8 microns, the matching contact surface of the positioning cone and a taper sleeve of the high-precision air bearing is more than or equal to 80 percent, and the requirement on the coaxiality of installation is ensured.

As a preferable scheme of the invention, the marble platform is a 00-level marble flat plate, and the levelness requirement (less than or equal to 0.02mm) of the platform is ensured by the horizontal fine-tuning block. The marble platform separates and insulates the space target simulation piece from the metal rotating platform support, so that other metal parts in the electromagnetic field environment have no influence on target racemization.

As a preferable scheme of the invention, the vacuum cover body and the tower-type multilayer cover plate are both made of transparent PC materials with the thickness of 10mm, so that the vacuum cover has better toughness and strength characteristics while ensuring the requirements of light transmission (being convenient for observing test effects) and insulation (being non-metallic conductors), and ensures that the deformation of the vacuum cover is within the allowable range of strength during vacuum pumping. The vacuum cover body is placed on a sealing groove on the marble platform, an EPDM rubber sealing strip is placed in the sealing groove, and a closed space is naturally formed during vacuumizing.

The left spinning air tap and the right spinning air tap are oppositely arranged in parallel and respectively aligned with the front fan blade and the rear fan blade of the wind impeller, and the air jet flow can be precisely adjusted.

A ground test method for simulating space target electromagnetic-eddy current racemization comprises the following steps:

the method comprises the following steps: leveling a marble table provided with a high-precision air bearing by using a level bar, installing a space target simulation piece, and leveling for the second time by using the level bar.

Step two: slightly rotating the space target simulation piece, measuring the jumping of the edge of the upper top of the space target simulation piece by a micrometer, ensuring that the coaxiality of the target is not more than 0.05mm in a rotating state, and then tightening the taper sleeve locking mechanism.

Step three: placing a vacuum cover, and vacuumizing by using a vacuum pump until the vacuum degree required by the experimental design is reached; and the vacuum pump is used for continuously vacuumizing in the test process so as to maintain the vacuum degree all the time.

Step four: and starting the air injection mechanism, and enabling the air injection nozzle to aim at the air impeller to inject air so as to slowly start the rotation of the space target simulation piece and stop air injection after the space target simulation piece reaches and stabilizes at the expected rotation speed. And measuring the rotation speed attenuation change of the space target simulation piece until the space target simulation piece stops rotating.

Step five: the electromagnetic actuator is maneuvered to a preset relative position and posture, and is electrified to generate an electromagnetic field so as to achieve the designed required magnetic field intensity. And (4) restarting the air injection mechanism, aligning the air injection nozzle with the air impeller to inject air, slowly starting the space target simulation piece, and stopping air injection after the expected rotating speed of the step four is reached and stabilized. And measuring the rotation speed attenuation change of the space target simulation piece until the space target simulation piece stops rotating.

Step six: and comparing the measurement results of the step four and the step five, and analyzing to obtain the racemization capacity and action characteristic of the electromagnetic-eddy current.

Setting different magnetic field strengths required by the test and different expected rotating speeds of the space target simulation part, repeating the test according to the method from the first step to the sixth step, and analyzing to obtain the electromagnetic-eddy current racemization capability and action characteristic under different magnetic field strengths and expected rotating speeds.

Compared with the prior art, the method has the advantages and beneficial effects that:

the invention provides a ground test system scheme for simulating space target electromagnetic-eddy current despinning. The method can realize effective simulation of the long-time free rotation state of the target by combining the high-precision air bearing and the vacuum cover, does not interfere with the action of an external magnetic field, and is suitable for despinning of electromagnetic eddy currents. Meanwhile, the electromagnetic actuator designed based on the high-temperature superconducting material can meet the requirement of larger magnetic field intensity, and the servo guide rail and the servo rotary table meet the three-degree-of-freedom electromagnetic racemization test design.

Drawings

FIG. 1 is a schematic diagram of a ground-based testing system for simulating electromagnetic-eddy current racemization of a spatial target according to an embodiment of the present invention.

FIG. 2 is a top view of a test system with the vacuum hood top tower multi-layer cover removed in one embodiment of the present invention.

FIG. 3 is a top view of a vacuum housing according to an embodiment of the present invention.

Illustration of the drawings:

the device comprises a rotary platform support 1, a servo guide rail 2, an air injection support 3, a left screwing-up air nozzle 4, a right screwing-up air nozzle 5, a fan wheel 6, a laser tachometer 7, a rotary table support 8, a horizontal fine adjustment block 9, a servo rotary table 10, a dynamic seal air leakage port 11, a high-precision air bearing 12, a marble table 13, a positioning cone 14, a sealing groove 15, an air suction hole 16, a cone sleeve locking mechanism 17, a space target simulation part 18, a vacuum cover body 19, an electromagnetic actuator 20, a tower-type multilayer cover plate 21 and a self-locking bolt 22.

Detailed Description

In order to make the technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, the embodiment provides a ground test system for simulating despinning of space targets by electromagnetic-eddy currents, which includes a rotating platform support 1, a servo guide rail 2, an air injection support 3, a left start-up air nozzle 4, a right start-up air nozzle 5, an air vane wheel 6, a laser tachometer 7, a turntable support 8, a horizontal fine adjustment block 9, a servo turntable 10, a dynamic seal air leakage port 11, a high-precision air bearing 12, a marble table 13, a positioning cone 14, a seal groove 15, an air suction hole 16, a cone sleeve locking mechanism 17, a space target simulation piece 18, a vacuum cover body 19, an electromagnetic actuator 20, a tower-type multilayer cover plate 21 and a self-locking bolt 22.

The space target simulation piece is arranged in a vacuum container, and an electromagnetic field generating device is arranged on the outer side edge of the vacuum container and used for generating an electromagnetic field. The electromagnetic field generating device comprises an electromagnetic actuator 20, a servo turntable 10, a turntable support 8 and a servo guide rail 2. The electromagnetic actuator 20 is fixed on the servo turntable 10, and the servo turntable 10 realizes the rotation control of the electromagnetic actuator 20; the servo turntable 10 is fixed at the center of the turntable support 8, the turntable support 8 is above the servo guide rail 2 and can move along the guide rail direction of the servo guide rail 2, and further the electromagnetic actuator 20 can be driven to realize linear motion control. In this embodiment, the length of the servo guide rail 2 is 1100mm, and the positioning precision of the guide rail direction is 0.1 mm. The stroke of the servo turntable is minus 180 degrees to plus 180 degrees, and the rotation precision is 0.1 degree. The electromagnetic actuator 20 is wound with an electromagnetic coil based on a high-temperature superconducting material, is provided with a special cooling device for maintaining the low-temperature environment of the superconducting material, and is powered by a low-voltage large-current power supply, so that a larger controllable electromagnetic field can be generated under the same size of a normal conductive coil. The space target simulation piece 18 is of an aluminum alloy structure and is in the shape of a cylindrical shell or a spherical shell, the diameter deviation of the shell is less than or equal to 0.2mm, the concentricity deviation is less than or equal to 5 mu m, and the dynamic balance standard is less than or equal to G2.5 (according to GB/T9239.1-2006/ISO1940-1: 2003).

The space target simulation piece 18 is fixedly connected with the positioning cone 14 along the axis, the positioning cone 14 is vertically inserted into a cone sleeve of the high-precision air bearing 12, and the fixing in the vertical direction is realized through a cone sleeve locking mechanism 17. The high-precision air bearing 12 is arranged in the center of the marble platform 13, the marble platform 13 is positioned above the rotating platform support 1, and the level of the marble platform is adjusted through the four level fine adjustment blocks 9 between the marble platform 13. The fan impeller 6 is arranged at the center of the bottom of the high-precision air bearing 12, the screwing-up left air nozzle 4 and the screwing-up right air nozzle 5 are arranged on the air injection bracket 3 in parallel, and the air injection ports are aligned with blades of the fan impeller 6. The laser tachometer 7 is arranged at a proper position of the rotating platform support 1, is aligned with the black and white division marks on the blades of the wind impeller 6 and is used for measuring the real-time rotating speed of the wind impeller. The wind impeller 6 drives the space target simulation piece 18 to synchronously rotate through the high-precision air bearing 12, and the real-time rotating speed of the wind impeller is the real-time rotating speed of the space target simulation piece 18.

The vacuum container comprises a vacuum cover body 19 and a tower type multi-layer cover plate 21, wherein the top surface of the vacuum cover body 19 is sealed by the tower type multi-layer cover plate 21. The tower type multi-layer cover plate comprises a plurality of layers of cover plates which are stacked in a tower type, and the multi-layer cover plates are fastened together through a central self-locking bolt 22. The bottom of the vacuum cover 19 is arranged in a sealing groove 15 correspondingly arranged on the marble table 13, wherein an EPDM rubber sealing strip is arranged in the sealing groove 15. Four air exhaust holes are formed in the marble platform, the vacuum pump is used for vacuumizing the space in the vacuum cover body through the four air exhaust holes 16, and a closed space is naturally formed during vacuumizing. Be provided with dynamic seal disappointing mouth 11 between high accuracy air bearing and the marble platform, high accuracy air bearing 12 ventilates the back, through the air that 11 exhaust of dynamic seal disappointing mouths, makes the air get into the internal space of vacuum cover as few as possible.

In the embodiment, the high-precision air bearing 12 is a high-precision air bearing with an air-driven sealing structure, the axial load is more than or equal to 60kg, the radial load is more than or equal to 10kg, the radial rotation error is less than or equal to 1.0 mu m, the axial rotation error is less than or equal to 1.0 mu m, the coaxiality is less than or equal to 2.0 mu m, and the air supply pressure is 0.5-0.7 MPa. The vacuum degree of the pneumatic sealing structure is less than or equal to 100 Pa.

The roundness of the surface of the positioning cone 14 is less than or equal to 5 mu m, the total runout of the conical surface is less than or equal to 8 mu m, the matching contact surface with the positioning cone sleeve of the high-precision air bearing 12 is more than or equal to 80 percent, and the requirement on the coaxiality of installation is ensured.

The marble platform 13 is a 00-level marble flat plate, and the levelness requirement (less than or equal to 0.02mm) of the platform is ensured through the horizontal fine adjustment block 9; the marble table 13 isolates the spatial target simulation 18 from the metal rotating platform support 1 so that other metal components have no effect on target racemization.

The vacuum cover body 19 and the tower-type multilayer cover plate 21 are both made of 10 mm-thick PC materials, so that the vacuum cover has better toughness and strength characteristics while meeting light transmission requirements (convenient for viewing test effects) and insulation requirements (non-metallic conductors), and the deformation of the vacuum cover is within an allowable strength range during vacuum pumping. The vacuum cover 19 is placed on the sealing groove 15 on the marble table 8, and a sealed space is naturally formed during vacuum pumping.

The left screwing-up air tap 4 and the right screwing-up air tap 5 are oppositely arranged on two sides of the wind impeller in parallel and respectively aligned with the front fan blade and the rear fan blade of the wind impeller 6, and the jet flow can be precisely adjusted.

In this embodiment, as shown in fig. 1, the electromagnetic actuator 20 is formed by winding a high-temperature superconducting material to form an electromagnetic coil, the inner diameter of the coil is 1m, a special cooling device is attached, the overall weight is large, and flexible movement is limited. Therefore, the electromagnetic actuator 20 is fixed on the servo turntable 10, and the accurate rotation control of-180 degrees to +180 degrees and the accuracy of 0.1 degree can be realized. The servo turntable 10 is arranged above the servo guide rail 2 through a turntable support 8 and can move linearly along the guide rail direction of the servo guide rail 2, and further the electromagnetic actuator 20 can be driven to realize the accurate position control with the content positioning accuracy of 0.1mm within the range of 1100 mm. The electromagnetic coil wound by the high-temperature superconducting material can pass larger current (less than or equal to 80A in the embodiment), so that an electromagnetic field ten times or even dozens of times of that of the traditional normal conducting coil can be generated. In addition, the controllable fine adjustment of the magnetic field intensity can be realized through current control.

The electromagnetic racemization target is composed of a space target simulation part 18, and the space target is simulated by adopting an aluminum alloy cylindrical shell and a spherical shell in consideration of the material and the structure of the actual spacecraft. When the space target is in a rotating state, the magnetic field action of the electromagnetic actuator can enable the target surface to generate eddy current, and further electromagnetic despinning torque acting on the space target is generated. In order to more accurately simulate the long-time free rotation state of a target in a space environment, high requirements are put forward on the dynamic balance characteristic of the ground space target simulation piece 18, and the dynamic balance standard of the space target simulation piece 18 is designed to be less than or equal to G2.5 according to the GB/T9239.1-2006/ISO1940-1:2003 standard. In addition, as can be seen from theoretical analysis, the larger the target size is, the larger the shell thickness is, the larger the electromagnetic racemization torque generated by the shell under the same magnetic field strength is, but the influence of simply increasing the target size and the thickness on racemization time is not obvious, and a better racemization effect is not necessarily achieved, so the size of the spatial target simulation piece in the embodiment is as follows: the height of the cylindrical shell is 500mm, the diameter is 500mm, and the thickness is 6 mm; the diameter of the spherical shell is 500mm, and the thickness is 6 mm.

The high-precision air bearing 12 is a core component for simulating a space target to freely rotate for a long time, and in order to effectively reduce friction, it is necessary to ensure coaxiality of the order of not more than tens of micrometers after the space target simulation member 18 is assembled. The positioning cone 14 is a connecting part of the space target simulation piece 18 and the high-precision air bearing 12, the positioning cone 14 is fixed at the axial center of the bottom of the space target simulation piece 18, the surface roundness of the conical surface is less than or equal to 5 microns, the total run-out of the conical surface is less than or equal to 8 microns, the positioning cone 14 is vertically inserted into a matched positioning cone sleeve of the high-precision air bearing 12, the matching contact surface with the positioning cone sleeve is guaranteed to be more than or equal to 80%, and the coaxiality requirement of the space target simulation piece 18 and the high-precision air bearing 12 in the vertical direction after installation can. After installation, the dial indicator is used for measuring the top edge jump of the space target simulation piece 18, and if the deviation is large and proper, the installation angle is adjusted until the coaxiality requirement is met.

The space target simulation part 18 rotates under the common atmospheric environment, and particularly, when the rotating speed is high, the atmosphere brings large frictional resistance, so that the target rotating speed can be quickly attenuated on one hand, and the electromagnetic racemization effect can be eliminated on the other hand. The vacuum vessel is therefore an essential means of maintaining the spatial target simulation 18 free to rotate for a long time.

The vacuum container is composed of a vacuum cover body 19, a tower type multi-layer cover plate 21 and a self-locking bolt 22. In order to avoid interference with a racemization electromagnetic field environment, the vacuum cover body 19 and the tower-type multilayer cover plate 21 are made of non-conductor transparent PC materials. As shown in fig. 3, the tower-type multi-layer cover plate 21 utilizes a multi-layer circular PC plate stacking structure and utilizes a central self-locking bolt 22 to realize close adhesion of the multi-layer plates, so that the pressure resistance of the top cover of the vacuum hood during vacuum pumping can be effectively improved. The tower-type multi-layer cover plate 21 is fixed above the vacuum cover body 19, and the edge of the cover plate is buckled below and tightly connected with the vacuum cover body 19. As shown in fig. 1 and 2, a vacuum cover 19 is placed on the sealing groove 15 of the marble table 13, and vacuum is drawn through four suction holes 16, and a closed space is naturally formed due to the action of gravity of the vacuum cover and atmospheric pressure during vacuum drawing.

In order to prevent the high-precision air bearing 12 from exhausting gas to damage the vacuum environment when working, the high-precision air bearing 12 is provided with a labyrinth type pneumatic sealing structure, air is exhausted along a dynamic sealing air leakage opening 11, and the air entering a vacuum cover is reduced as much as possible; in order to maintain the vacuum environment, the real-time vacuum degree in the vacuum cover needs to be monitored, and the vacuum pump is enabled to work continuously.

The wind impeller 6 is installed at the center of the bottom of the high-precision air bearing 12, the left rotating-starting air nozzle 4 and the right rotating-starting air nozzle 5 are installed on the air injection support 3 in parallel, air ports are respectively aligned with the front blade and the rear blade of the wind impeller 6, the high-precision air bearing 12 is driven to rotate through jet flow control, and jet flow is adjustable. The laser tachometer 7 is arranged at a proper position of the rotating platform support 1 and is aligned with black and white division marks on blades of the wind impeller 6, and when the high-precision air bearing 12 drives the space target simulation part 18 to rotate, the real-time rotating speed of the space target simulation part 18 can be measured by the laser tachometer 7.

The ground test method for simulating the racemization of the space target electromagnetism-vortex by sampling the test system comprises the following steps:

the method comprises the following steps: leveling the marble table 13 provided with the high-precision air bearing 12 by using a level ruler, installing a space target simulation piece 18, and secondarily leveling by using the level ruler to ensure the rotating levelness of the space target simulation piece.

Step two: slightly rotating the space target simulation piece 18, measuring the bounce of the edge of the upper top of the space target simulation piece 12 by a micrometer, ensuring that the coaxiality of the target is not more than 0.05mm in a rotating state, and then tightening the taper sleeve locking mechanism 17.

Step three: placing a vacuum cover, and vacuumizing by using a vacuum pump until the vacuum degree required by the experimental design is reached; and the vacuum pump is used for continuously vacuumizing in the test process so as to maintain the vacuum degree all the time.

Step four: and (3) starting the air injection mechanism, aligning the spinning left air nozzle 4 and the spinning right air nozzle 5 with the air impeller to inject air, slowly spinning the space target simulation piece 18, and stopping injecting air after reaching and stabilizing the expected rotating speed. The rotational speed decay change of the space target simulation 18 is measured until the space target simulation 18 stops rotating.

Step five: the electromagnetic actuator 20 is maneuvered to a preset relative position and posture, and is electrified to generate an electromagnetic field so as to achieve the designed required magnetic field intensity. And (4) restarting the air injection mechanism, aligning the left-handed air nozzle 4 and the right-handed air nozzle 5 with the air impeller to inject air, slowly turning the space target simulation piece 18, and stopping injecting air after the expected rotating speed of the step four is reached and stabilized. The rotational speed decay change of the space target simulation 18 is measured until the space target simulation 18 stops rotating.

Step six: and comparing the measurement results of the step four and the step five, and analyzing to obtain the racemization capacity and action characteristic of the electromagnetic-eddy current.

Setting different magnetic field strengths required by the test and different expected rotating speeds of the space target simulation part, repeating the test according to the method from the first step to the sixth step, and analyzing to obtain the electromagnetic-eddy current racemization capability and action characteristic under different magnetic field strengths and expected rotating speeds.

In the embodiment, the high-precision air bearing 12 is adopted to float the large-mass space target simulation part 18, and a near vacuum environment is provided for the rotation of the space target simulation part by adding the vacuum cover, so that the effective simulation of the long-time free rotation state of the target can be realized, the external magnetic field effect cannot be interfered, and the electromagnetic eddy current despinning device is suitable for electromagnetic eddy current despinning. The electromagnetic actuator designed based on the high-temperature superconducting material can meet the requirement of larger magnetic field intensity, and the servo guide rail and the servo rotary table meet the three-degree-of-freedom electromagnetic racemization test design.

In summary, although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.