A magnetic tensor measurement platform and method for uncontrolled tumbling targets in space

Abstract

The present invention relates to a measuring platform and a measuring method for the magnetic tensor of a space uncontrolled tumbling target. The measured magnetic tensor is used to calculate the derotation torque of the space target during the derotation process of eddy current. The measuring platform includes a non-magnetic optical vibration isolation table, a rotation simulation module, a magnetic field generation module, a magnetic intensity measurement module and a computer. The method is: the magnetic field intensity is measured by the magnetic intensity measurement module, the target angular velocity is controlled and measured by the rotation simulation module, the torque of the magnet is measured by the high-precision force sensor in the magnetic field generation module, and finally the magnetic tensor M of the space target is obtained according to the interaction of the force and the analytical formula of the electromagnetic derotation torque. This platform is not affected by the external magnetic field, and the interference factors are eliminated by using ceramic bearings, electromagnetic clutches, etc., and is suitable for the measurement of derotation data such as the magnetic tensor of space targets.

Description

Technical Field

[0001] The invention belongs to the technical field of non-contact derotation of an out-of-control tumbling target in space, and relates to a magnetic tensor measurement platform and a measurement method for an out-of-control tumbling target in space. Background Art

[0002] The rapid development of human space technology has led to an increasing number of satellites in Earth orbit. Among the 22,000 space targets tracked by the U.S. Air Force, only about 1,000 are satellites that are functioning normally, and the rest are mostly out-of-control satellites or various space junk, which seriously threaten space security. It is imperative to explore a method to systematically remove out-of-control targets in space orbit. Out-of-control space targets basically have no attitude adjustment ability and will tumble under the influence of space perturbations, so it is necessary to derotate them before capturing them.

[0003] Non-contact de-rotation avoids direct contact with the space tumbling target, effectively reduces the collision probability, and improves the safety of the de-rotation process. Among the non-contact de-rotation methods, eddy current de-rotation is more feasible than Coulomb force de-rotation and jet de-rotation, and has great development potential. At present, the angular velocity of the tumbling target is generally measured by visual recognition and the de-rotation torque is estimated by derivative. The obtained de-rotation torque has poor real-time and accuracy, making it difficult for the service satellite to stably track the tumbling target and de-rotate it. Natalia Ortiz Gómez et al. proposed a method for calculating eddy current torque based on magnetic tensor in the article "Eddy currents applied to de-tumbling of space debris: Analysis and validation of approximate proposed methods". The magnetic tensor is a symmetrical second-order tensor that is only related to the geometric shape and conductivity of the object. If the magnetic tensor of the high-speed tumbling target can be obtained, the corresponding de-rotation torque can be calculated in real time according to the target angular velocity and the applied magnetic field strength during actual de-rotation. Introducing it into the control system can effectively improve the stability of the system.

[0004] The magnetic tensor of an object can be obtained through theoretical calculation and actual measurement. Theoretical calculation is more difficult, and it is difficult to find an analytical solution for objects with complex shapes. In actual measurement, if the shaft system structure is used to drive the derotation target to rotate, there will be many sources of friction, large values ​​and instability; if superconducting magnetic levitation, air flotation and other methods are used to suspend the target, there will be problems such as difficulty in spinning, difficulty in obtaining and controlling the angular velocity, and easy interference with the magnetic field. Therefore, there is currently no platform for measuring the magnetic tensor of an object, which is not conducive to further research and verification of the eddy current derotation method and the implementation of eddy current derotation of uncontrolled tumbling targets in space. Summary of the invention

[0005] Technical issues to be solved

[0006] In order to avoid the shortcomings of the prior art, the present invention proposes a magnetic tensor measurement platform and a measurement method for a space uncontrolled tumbling target. The purpose is to solve the problems of multiple sources of friction, large values ​​and instability when simulating the rotation of a space tumbling target in the actual measurement process of the magnetic tensor. To address the above problems, the present invention proposes a space uncontrolled tumbling target magnetic tensor measurement platform and a measurement method that has no interference with the magnetic field, has low and nearly constant friction, can accurately measure angular velocity, torque, etc., and thus solve the target magnetic tensor.

[0007] Technical Solution

[0008] A magnetic tensor measurement platform for an out-of-control tumbling target in space, characterized in that it comprises a non-magnetic optical vibration isolation table 4, a rotation simulation module 1, a magnetic field generating module 2, a magnetic intensity measurement module 3 and a computer 5; the magnetic field generating module 3 is fixed on the non-magnetic optical vibration isolation table 4, one side of the magnetic field generating module 3 is the rotation simulation module 1 carrying the derotation target 6, and the side facing the derotation target is the magnetic intensity measurement module 3; the computer 5 controls the movement of the servo motor of the rotation simulation module 1, and receives data collected by the sensor of the magnetic intensity measurement module 3; the rotation simulation module is a servo motor 17 fixed on a planar turntable 16; the magnetic field generating module 3 comprises a cylindrical permanent magnet 19 and a force sensor 21 fixed thereto, the force sensor 21 measures the force and torque exerted on the permanent magnet 19 during the derotation process, displays them and transmits them to the computer 5; the magnetic intensity measurement module 3 adopts a gaussmeter 27.

[0009] The rotation simulation module: the motor rotor of the servo motor 17 is fixedly connected to the plane turntable 16 by bolts, and a groove is processed in the center of the plane turntable 16 for cooperating with the driving shaft 15, and the driving shaft 15 and the plane turntable 16 are connected by bolts; the electromagnetic clutch base 14 is fixed on an aluminum alloy plate, and the active friction plate 13 moves up and down; the small end of the driven shaft 11 limits the radial movement of the driven friction plate 12 of the electromagnetic clutch by a single round head flat key, and the end face of the driven shaft 11 is processed with a threaded hole, and the axial movement of the driven friction plate 12 is limited by screws; the outer shell of the optical encoder 10 is fixed, and the code disk is fixedly connected to the driven shaft 11 by bolts; the ceramic bearing 9 is fixed on the aluminum alloy plate, cooperates with the driven shaft 11 and plays a supporting role; the axis of the turntable 8 is processed with a groove for cooperating with the driven shaft 11, and the turntable 8 and the driven shaft 11 are connected by bolts.

[0010] The magnetic field generating module: the cylindrical permanent magnet 19 is placed in the permanent magnet fixture 18, the cover plate 20 is fixedly connected to the permanent magnet fixture 18 by bolts and nuts, and is fixedly connected to the upper cover of the force sensor 21 by bolts, the bottom plate 22 is processed with a groove, the force sensor 21 is fixed therein by bolts, and the bottom plate 22 is fixed on the cross slide 23 by bolts. The movement of the workbench of the cross slide 23 is controlled by the computer 5 to change the relative distance between the permanent magnet 19 and the de-rotation target 6, thereby changing the magnetic field strength at the de-rotation target 6. The force sensor 21 can display the force and torque exerted on the permanent magnet 19 during the de-rotation process and store them on the computer 5.

[0011] The magnetic intensity measurement module: the guide shaft support 26 is fixed on the optical platform by bolts, the straight rod 25 is fixed in the guide shaft support by a top screw, one end of the cross fixing clamp 24 is inserted into the straight rod, and the other end clamps the probe of the Gauss meter 27 and is clamped by bolts; after the de-rotation torque measurement is completed, the rotation simulation module 1 is removed, and the guide shaft support 26 is installed at the original position of the rotation simulation module 1, that is, the magnetic induction intensity at the center of the de-rotation target 6 is measured.

[0012] The force sensor 21 is a force sensor capable of measuring force and torque values ​​in three directions: X, Y, and Z.

[0013] The cover plate, the bottom plate and the permanent magnet fixture are made of nylon material to avoid being magnetized and causing changes in magnetic field strength.

[0014] A method for measuring using the space uncontrolled tumbling target magnetic tensor measurement platform is characterized by the following steps:

[0015] Step 1: Install the de-rotation target on the turntable, control the electromagnetic clutch to close, connect the servo motor and the turntable through the driven shaft and the driving shaft, install the optical encoder on the driven shaft section, and support each part through an aluminum alloy frame to form a rotation simulation module; install the force sensor between the bottom plate and the cover plate, fix the bottom plate on the cross slide workbench, and connect the permanent magnet to the cover plate through a permanent magnet fixture to form a magnetic field generation module, control the cross slide to move to the specified position, and use a computer to control the servo motor to drive the de-rotation target to rotate around its X, Y, and Z axes in sequence;

[0016] Step 2: After the derotation target reaches the specified angular velocity and the angular velocity fluctuation is small, the electromagnetic clutch is disconnected by computer control, and the target single-axis rotation angular velocity-time data ω is measured by optical encoder i (t), i = 1, 2, 3 and recorded in the computer, the torque exerted on the permanent magnet when the de-rotation target rotates is measured by the force sensor and recorded in the computer, and the electromagnetic de-rotation torque-time data T exerted on the target is obtained according to the interaction of the forces i (t);

[0017] Step 3: Remove the rotation simulation module, fix the Gaussmeter probe to the position of the center of the de-rotation target in step 1 through the cross clamp, straight rod and guide shaft support, and use the Gaussmeter to measure the magnetic field intensity B at this point;

[0018] Step 4: Calculate the magnetic tensor according to the target uniaxial rotation formula

[0019]

[0020] Calculate the components of the magnetic tensor M ii (t) and select a relatively stable section to calculate the average value to obtain the measured values ​​of each component of the target magnetic tensor

[0021] Beneficial Effects

[0022] The present invention proposes a space uncontrolled tumbling target magnetic tensor measurement platform and measurement method, the measured magnetic tensor is used to calculate the derotation torque of the space target during the eddy current derotation process. The measurement platform includes a non-magnetic optical vibration isolation table, a rotation simulation module, a magnetic field generation module, a magnetic field measurement module and a computer. The method is: using the magnetic field measurement module to measure the magnetic field strength Use the rotation simulation module to control and measure the target angular velocity The torque exerted on the magnet is measured by the high-precision force sensor in the magnetic field generating module, and finally the magnetic tensor M of the space target is obtained by solving the analytical formula of the force interaction and electromagnetic derotation torque. This platform is not affected by the external magnetic field, and the use of ceramic bearings and electromagnetic clutches eliminates interference factors, making it suitable for the measurement of derotation data such as the magnetic tensor of space targets.

[0023] The present invention has the following beneficial technical effects:

[0024] The present invention proposes a measurement platform and method for the magnetic tensor of an out-of-control tumbling target in space, which can obtain the magnetic tensor of a high-speed tumbling target in space, so that the electromagnetic derotation torque can be introduced into the control system, thereby improving the safety of the derotation mission.

[0025] The present invention uses ceramic bearings to reduce resistance during rotation, avoids the use of lubricants, and ensures that friction does not change with speed. An electromagnetic clutch is used, and after the clutch is disconnected, the rotor and the stator are separated under the action of gravity, avoiding the introduction of friction between the clutch and the motor part, and solving the problem that when the shaft system structure drives the de-rotation target to rotate, the friction sources are many, the values ​​are large, and the instability is solved. Aluminum alloy and nylon materials are used to make structural parts, and the device is not easy to magnetize or generate a magnetic field, solving the problem that the magnetic field is easily disturbed, and thus data with higher reliability can be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the structural diagram of the magnetic tensor measurement platform for uncontrolled tumbling targets in space;

[0027] Figure 2 This is a schematic diagram of a rotation simulation module of a space uncontrolled tumbling target magnetic tensor measurement platform;

[0028] Figure 3 A schematic diagram of a magnetic field generating module of a space uncontrolled tumbling target magnetic tensor measurement platform;

[0029] Figure 4 It is a schematic diagram of the installation of the permanent magnet in the magnetic field generating module;

[0030] Figure 5 This is a schematic diagram of the installation of the force sensor in the magnetic field generating module;

[0031] Figure 6 Schematic diagram of the magnetic intensity measurement module of the magnetic tensor measurement platform for uncontrolled tumbling targets in space.

[0032] Description of reference numerals:

[0033] 1 is a rotation simulation module, 2 is a magnetic field generating module, 3 is a magnetic intensity measuring module, 4 is a non-magnetic optical vibration isolation table, 5 is a computer, 6 is a de-rotation target, 7 is a nylon stud bolt and nut combination, 8 is a turntable, 9 is a ceramic bearing, 10 is an optical encoder, 11 is a driven shaft, 12 is an electromagnetic clutch driven friction plate, 13 is an electromagnetic clutch active friction plate, 14 is an electromagnetic clutch base, 15 is an active shaft, 16 is a plane turntable, 17 is a servo motor, 18 is a permanent magnet fixture, 19 is a permanent magnet, 20 is a cover plate, 21 is a force sensor, 22 is a bottom plate, 23 is a cross slide, 24 is a cross fixing clamp, 25 is a straight rod, 26 is a guide shaft support, and 27 is a Gauss meter. DETAILED DESCRIPTION

[0034] The present invention will now be further described with reference to the embodiments and the accompanying drawings:

[0035] like Figure 1 As shown, the measurement platform consists of a rotation simulation module 1, a magnetic intensity measurement module 2, a magnetic field generating module 3, a non-magnetic optical vibration isolation table 4, and a computer 5. The rotation simulation module 1, the magnetic intensity measurement module 2, and the magnetic field generating module 3 are fixed on the optical platform 4. The servo motor 17 and the like are controlled by the computer 5, and the data collected by the sensor are received.

[0036] The structure of the rotation simulation module is as follows Figure 2As shown, the base of the servo motor 17 is fixed on an aluminum alloy plate, and the motor rotor is fixedly connected to the plane turntable 16 by bolts. A groove is processed in the center of the plane turntable 16 for matching with the driving shaft 15, and the driving shaft 15 and the plane turntable 16 are connected by bolts. The electromagnetic clutch base 14 is fixed on an aluminum alloy plate, and the active friction plate 13 can move up and down. A keyway is processed on the small end of the driven shaft 11, and the radial movement of the driven friction plate 12 of the electromagnetic clutch is limited by a single round head flat key. The end face of the driven shaft 11 is processed with a threaded hole, and the axial movement of the driven friction plate 12 is limited by screws. The housing of the optical encoder 10 is fixed, and the code disk is fixedly connected to the driven shaft 11 by bolts. The ceramic bearing 9 is fixed on the aluminum alloy plate, matching with the driven shaft 11 and playing a supporting role. A groove is processed on the axis of the turntable 8 for matching with the driven shaft 11, and the turntable 8 and the driven shaft 11 are connected by bolts. The de-rotation target 6 can be replaced according to the target to be measured. In this embodiment, it is a rectangular shell, and threaded holes are processed on three mounting surfaces. It is fixed to the turntable 8 by a nylon stud bolt and nut combination 7. When the electromagnetic clutch is energized, the active friction plate 13 of the electromagnetic clutch and the driven friction plate 12 are attracted by magnetic force, so that the servo motor 17 can drive the de-rotation target 6 to rotate. After the electromagnetic clutch is disconnected, the active friction plate 13 is separated from the driven friction plate 12 under the action of gravity to avoid interfering with the rotation of the target 6. The optical encoder 10 can measure the rotation speed ω of the driven shaft 11 and store it in the computer 5.

[0037] The structure of the magnetic field generating module is as follows: Figure 3 As shown, the cylindrical permanent magnet 19 is placed in the permanent magnet fixture 18, as shown in FIG. Figure 4 The cover plate 20 is fixedly connected to the permanent magnet fixture 18 by bolts and nuts, and is fixedly connected to the upper cover of the force sensor 21 by bolts. The bottom plate 22 is processed with a groove, and the force sensor 21 is fixed therein by bolts. Figure 5 The bottom plate 22 is fixed on the cross slide 23 by bolts, and the worktable movement of the cross slide 23 is controlled by the computer 5 to change the relative distance between the permanent magnet 19 and the de-rotation target 6, thereby changing the magnetic field strength at the de-rotation target 6. The force sensor 21 can display and store the force and torque exerted on the permanent magnet 19 during the de-rotation process on the computer 5.

[0038] The magnetic intensity measurement module consists of Figure 6 As shown, the guide shaft support 26 is fixed on the optical platform by bolts, the straight rod 25 is fixed in the guide shaft support by a top screw, and the cross fixing clamp 24 is inserted into the straight rod at one end and clamps the probe of the Gauss meter 27 at the other end, and is clamped by bolts. After the de-rotation torque measurement is completed, the rotation simulation module 1 is removed, and the guide shaft support 26 is installed at the original position of the rotation simulation module 1, and the magnetic induction intensity at the center of the de-rotation target 6 can be measured.

[0039] The optical encoder 10 is Z48-J12C, with a resolution of 2500P / R, 8 poles, and a maximum speed of 5000rpm.

[0040] The servo motor 17 is of model GM6020, with a rated torque of 1.2 N·m and a maximum no-load speed of 320 rpm.

[0041] The maximum load of the cross slide 23 is 25 kg, and the maximum operating speed is 500 mm / s.

[0042] The gaussmeter 27 is a CH-1500 digital gaussmeter with a resolution of 0.01 mT, and can measure the magnetic field strength in the direction perpendicular to the transverse probe.

[0043] The force sensor 21 is ATI Mini40-E, which can measure the force and torque values ​​in the X, Y and Z directions. The maximum load-bearing capacity in the Z direction is 800N, and the maximum load-bearing capacity in the X and Y directions is 240N. The force measurement resolution is 1 / 100N, and the torque measurement resolution is 1 / 4000N / m.

[0044] The cover plate, the bottom plate and the permanent magnet fixture are made of nylon material, which can avoid being magnetized and causing changes in magnetic field intensity.

[0045] The specific steps of measuring the de-racemation target magnetic tensor in this embodiment are:

[0046] Step 1: Establish a world coordinate system X1Y1Z1 with the center of the non-magnetic optical vibration isolation table 4 as the origin, and establish a body-fixed coordinate system X2Y2Z2 with the center of the de-racemized target 6 as the origin, as shown in Figure 1 As shown, the rotation simulation module 1 is fixed on the non-magnetic optical vibration isolation table 4, and the cross slide 23 worktable is controlled by the computer 5 to move to the specified position so that the center of the permanent magnet 19 and the center of the de-rotation target 6 have the same y coordinate in the X1Y1Z1 coordinate system.

[0047] Step 2: Control the electromagnetic clutch to close through the computer 5, start the servo motor 17 and set its speed. When the speed fluctuation is small, disconnect the electromagnetic clutch, turn off the servo motor, and start recording the angular velocity-time data ω1(t) collected by the optical encoder 10 and the torque-time data T1(t) collected by the force sensor 21. Then, the angular velocity vector is Torque vector of target

[0048] Step 3: Remove the de-rotation target 6 and rotate it 90° around the Y1 axis so that the Z2 axis of the fixed coordinate system is in the same direction as the X1 axis. Then install it on the rotation simulation module and repeat step 2. Assume that the measured angular velocity-time data is ω2(t) and the torque-time data is T2(t). Then, in the X2Y2Z2 coordinate system, the angular velocity vector Torque Vector

[0049] Step 4: Remove the derotation target 6, rotate it 90° along the X1 axis, and then install it on the rotation simulation module. Repeat step 2. Assume that the measured angular velocity-time data is ω3(t) and the torque-time data is T3(t). Then, in the X2Y2Z2 coordinate system, the angular velocity vector Torque Vector

[0050] Step 5: Remove the rotation simulation module 1, fix the guide shaft support 26 to the original position of the rotation simulation module 1, adjust the height of the cross fixing clamp 24, so that the probe of the Gauss meter 27 is at the center of the original position of the de-rotation target 6 and the probe face is facing the permanent magnet 19. Suppose the measured magnetic induction intensity is B x .

[0051] Step 6: Rotate the probe of the Gaussmeter 27 by 90° and measure again. Suppose the measured magnetic induction intensity is B. y , then the central magnetic induction intensity of the original position of the deracinated target 6 is In the body-fixed coordinate system X2Y2Z2 of the de-racemized target 6, the magnetic induction vectors of the de-racemized target when rotating around the X2, Y2, and Z2 axes are:

[0052] The magnetic tensor M can be expressed as a diagonal matrix:

[0053]

[0054] Will Substitute into the electromagnetic de-rotation torque calculation formula:

[0055]

[0056] The calculation formulas for each component of the magnetic tensor M can be obtained:

[0057]

[0058] Step 7: Substitute ω into the formula for calculating the components of the magnetic tensor M. i (t)(i=1,2,3),T i (t)(i=1,2,3)getM ii (t)(i=1,2,3), select a relatively stable section in the obtained magnetic tensor component-time curve and calculate its average value The measured value of the magnetic tensor of the deracinated target 6 is obtained

[0059] The above descriptions are only preferred specific embodiments of the present invention, which are different implementation methods based on the overall concept of the present invention. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also includes equivalent technical means that can be thought of by those skilled in the art based on the concept of the present invention.

Claims

1. A space uncontrolled tumbling target magnetic tensor measurement platform, characterized in that The invention comprises a non-magnetic optical vibration isolation table (4), a rotation simulation module (1), a magnetic field generating module (2), a magnetic field measurement module (3) and a computer (5); the magnetic field generating module (2) is fixed on the non-magnetic optical vibration isolation table (4); one side of the magnetic field generating module (2) is a rotation simulation module (1) carrying a derotation target (6); the other side facing the derotation target is a magnetic field measurement module (3); the computer (5) controls the movement of a servo motor of the rotation simulation module (1) and receives data collected by a sensor of the magnetic field measurement module (3); the rotation simulation module is a servo motor (17) fixed on a planar turntable (16); the magnetic field generating module (2) comprises a cylindrical permanent magnet (19) and a force sensor (21) fixed thereto; the force sensor (21) measures the force and torque exerted on the permanent magnet (19) during the derotation process, displays the measured force and torque, and transmits the measured force and torque to the computer (5); the magnetic field measurement module (3) uses a gauss meter (27); The rotation simulation module comprises: a motor rotor of a servo motor (17) is fixedly connected to a plane turntable (16) by bolts; a groove is processed at the center of the plane turntable (16) for cooperating with a driving shaft (15), and the driving shaft (15) and the plane turntable (16) are connected by bolts; an electromagnetic clutch base (14) is fixed on an aluminum alloy plate, and an active friction plate (13) moves up and down; a single round head flat key is used at the small end of a driven shaft (11) to limit the radial movement of a driven friction plate (12) of the electromagnetic clutch; a threaded hole is processed at the end face of the driven shaft (11), and a screw is used to limit the axial movement of the driven friction plate (12); an optical encoder (10) is fixed to a housing, and a code disc is fixedly connected to the driven shaft (11) by bolts; a ceramic bearing (9) is fixed on the aluminum alloy plate, and cooperates with the driven shaft (11) and plays a supporting role; a groove is processed at the axis of a turntable (8) for cooperating with the driven shaft (11), and the turntable (8) and the driven shaft (11) are connected by bolts; The magnetic field generating module comprises: a cylindrical permanent magnet (19) is placed in a permanent magnet fixture (18); a cover plate (20) is fixedly connected to the permanent magnet fixture (18) by bolts and nuts, and is fixedly connected to the upper cover of a force sensor (21) by bolts; a bottom plate (22) is processed with a groove, in which the force sensor (21) is fixed by bolts; the bottom plate (22) is fixed on a cross slide (23) by bolts; a computer (5) is used to control the movement of the workbench of the cross slide (23) to change the relative distance between the permanent magnet (19) and the de-rotation target (6), thereby changing the magnetic field strength at the de-rotation target (6); the force sensor (21) can display the force and torque exerted on the permanent magnet (19) during the de-rotation process and store them on the computer (5); The magnetic intensity measurement module: the guide shaft support (26) is fixed on the optical platform by bolts, the straight rod (25) is fixed in the guide shaft support by a top screw, one end of the cross fixing clamp (24) is inserted into the straight rod, and the other end clamps the probe of the Gauss meter (27) and is clamped by bolts; after the de-rotation torque measurement is completed, the rotation simulation module (1) is removed, and the guide shaft support (26) is installed at the original position of the rotation simulation module (1), that is, the magnetic induction intensity at the center of the de-rotation target (6) is measured.

2. According to claim 1, the space uncontrolled tumbling target magnetic tensor measurement platform is characterized by: The force sensor (21) is a force sensor capable of measuring force and torque values ​​in three directions: X, Y and Z.

3. According to claim 1, the space uncontrolled tumbling target magnetic tensor measurement platform is characterized by: The cover plate, bottom plate and permanent magnet fixture are made of nylon material to avoid being magnetized and causing changes in magnetic field intensity.

4. A method for measuring a target magnetic tensor of an uncontrolled tumbling space using the space uncontrolled tumbling target magnetic tensor measurement platform according to any one of claims 1 to 3, characterized in that Here are the steps: Step 1: Install the de-rotation target on the turntable, control the electromagnetic clutch to close, connect the servo motor and the turntable through the driven shaft and the driving shaft, install the optical encoder on the driven shaft section, and support each part through an aluminum alloy frame to form a rotation simulation module; install the force sensor between the bottom plate and the cover plate, fix the bottom plate on the cross slide workbench, and connect the permanent magnet to the cover plate through a permanent magnet fixture to form a magnetic field generation module, control the cross slide to move to the specified position, and use a computer to control the servo motor to drive the de-rotation target to rotate around its X, Y, and Z axes in sequence; Step 2: After the derotation target reaches the specified angular velocity and the angular velocity fluctuation is small, the electromagnetic clutch is disconnected by computer control, and the target single-axis rotation angular velocity-time data ω is measured by optical encoder i (t), i = 1, 2, 3 and recorded in the computer, the torque exerted on the permanent magnet when the de-rotation target rotates is measured by the force sensor and recorded in the computer, and the electromagnetic de-rotation torque-time data T exerted on the target is obtained according to the interaction of the forces i (t); Step 3: Remove the rotation simulation module, fix the Gaussmeter probe to the position of the center of the de-rotation target in step 1 through the cross clamp, straight rod and guide shaft support, and use the Gaussmeter to measure the magnetic field intensity B at this point; Step 4: Calculate the magnetic tensor according to the target uniaxial rotation formula Calculate the components of the magnetic tensor M ii (t) and select a relatively stable section to calculate the average value to obtain the measured values ​​of each component of the target magnetic tensor

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