A torsional pendulum type micro-thrust test system and a measuring method

Abstract

The application is a torsional pendulum type micro-thrust test system and measuring method, which comprises a working base plate, a torsional pendulum beam, a flexible pivot, a micro-thrust engine, a counterweight, a fixing device, a micro-thrust generating device, a displacement measuring device, a damping structure and a calibration module; the torsional pendulum beam is suspended by the fixing device, and the upper surface of the torsional pendulum beam is provided with the micro-thrust engine and the counterweight at two ends respectively; the damping structure is installed on the working base plate in the same horizontal line as the torsional pendulum beam; the micro-thrust generating device is installed on the working base plate on one side of the torsional pendulum beam, and is composed of two opposite electromagnetic coils and a power supply wire to generate a small thrust; and the displacement measuring device is installed on the working base plate on the opposite side of the torsional pendulum beam and the micro-thrust generating device. The micro-thrust generating device of the application is composed of two electromagnetic coils and a power supply wire to generate a small thrust, and the magnetic pole surface has sufficient width, so that the working area of the power supply wire is in a uniform magnetic field, and the precision is improved.

Description

Technical Field

[0001] This invention belongs to the field of micro-thrust measurement, specifically relating to a torsion pendulum type micro-thrust testing system and measurement method. Background Technology

[0002] In recent years, with the rapid development and widespread application of microsatellites and nanosatellites, micro-propulsion systems have become a key focus of microsatellite research, which has also placed new demands on the accurate measurement of micro-thrust. The thrust generated by micro-thrusters is extremely small, typically on the order of mN or even lower, posing certain difficulties for the accurate measurement of micro-thrust. Therefore, it is essential to develop a high-precision micro-thrust testing system.

[0003] Based on the fundamental principles of micro-thrust measurement, researchers both domestically and internationally have developed various types of micro-thrust testing systems to meet the requirements of different types of micro-thrusters. Common micro-thrust testing systems include torsion pendulum type, balance type, simple pendulum type, and suspension wire type. Among them, the balance type micro-thrust testing system can achieve micro-thrust measurement in the mN to N range, but its resolution is not high; the simple pendulum type can achieve micro-thrust measurement in the μN to mN range, but it cannot eliminate the influence of gravity on the test results; the suspension wire type has high accuracy and small size, but is easily affected by environmental interference; the torsion pendulum type can achieve micro-thrust measurement in the μN range and can separate gravity and thrust, with high resolution.

[0004] Currently, various torsion pendulum-type micro-thrust testing systems have been designed and researched in China. Publication number CN114964588A discloses a torsion pendulum-type micro-thrust measuring device and method, and publication number CN115248120A discloses a micro-thrust measuring device and method. Both of these micro-thrust measuring devices use a combination of permanent magnets and electromagnetic coils to generate minute thrust. However, since the permanent magnets and energized coils are placed separately in the measurement environment, they are susceptible to interference from electromagnetic fields in the space, affecting the accuracy of the electromagnetic force output of the measuring device. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing micro-thrust testing system technologies by providing a simple, high-precision torsion pendulum-type millinewton-level micro-thrust testing system.

[0006] The technical solution to achieve the purpose of this invention is: a torsion pendulum type micro-thrust testing system, including a working base plate and a torsion pendulum crossbeam, a flexible pivot, a micro-thrust engine, a counterweight, a fixing device, a micro-thrust generating device, a displacement measuring device, a damping structure, and a calibration module disposed on the working base plate.

[0007] The torsion beam is suspended on the working base plate by a fixing device. The two ends of the upper surface of the torsion beam are respectively equipped with a micro-thrust engine and a counterweight through a single-axis displacement platform. The damping structure is installed on the working base plate at the same horizontal line as the torsion beam to generate electromagnetic resistance so that the torsion beam stops swinging horizontally and provides the damping ratio required for measurement. The micro-thrust generating device is installed on the working base plate on one side of the torsion beam. It generates a small thrust by combining two oppositely installed electromagnetic coils and current-carrying wires. The displacement measuring device (7) is installed on the working base plate on the opposite side of the torsion beam and the micro-thrust generating device (6). The relative distance data between the displacement measuring device (7) and the side surface of the torsion beam is measured by an eddy current displacement sensor. The calibration module (9) is installed on the working base plate on the same side as the micro-thrust generating device and is used to calibrate the functional relationship between the micro-thrust and the current.

[0008] Furthermore, the torsion beam is an I-beam and serves as the actuating component, which will swing horizontally when a small thrust is applied.

[0009] Furthermore, the flexible pivot serves as a measurement sensing element. When the torsion beam swings, the flexible pivot twists accordingly. The flexible pivot is fixed relative to the torsion beam, and both ends of the flexible pivot are rigidly fixed.

[0010] Furthermore, the fixing device includes a right-angle fixing block, an optical axis fixing ring, an adjustment mechanism, and a support assembly;

[0011] The right-angle fixing block is fixed at the top of the adjustment mechanism. The support component passes through the corresponding through hole on the torsion beam and is fixedly connected to the torsion beam. The middle of the support component is provided with a through hole for the flexible pivot to pass through. The flexible pivot and the support component are connected in a way that prevents them from moving relative to each other. The upper and lower ends of the flexible pivot are connected by an optical axis fixing ring, a right-angle fixing block and a transition plate, respectively. The adjustment mechanism is a three-axis displacement adjustment platform.

[0012] Furthermore, the displacement measuring device includes, from top to bottom, an eddy current sensor and a fixed bracket;

[0013] The eddy current sensor includes an eddy current probe and an adjustment circuit preamplifier. The eddy current probe is mounted on a fixed base plate by a fixed bracket, and the adjustment circuit preamplifier is placed on a working base plate on one side of the fixed bracket and connected to an external power supply.

[0014] Furthermore, the damping structure includes two electromagnets of the same size arranged opposite each other, a damping plate with one end set between the two electromagnets, a right-angle fixing block, a Z-axis single-axis displacement stage, and an optical breadboard.

[0015] The right-angle fixing block is fixed to the optical breadboard with bolts, the upper electromagnet is fixed to the lower surface of the suspended right-angle fixing block, and the lower electromagnet is fixed to the working base plate through the adapter block.

[0016] The other end of the damping plate is fixedly connected to the lower surface of the I-beam web.

[0017] Furthermore, the micro-thrust generating device includes an electromagnetic coil of the same specification arranged vertically opposite to each other, a first energized wire, and a fixed bracket;

[0018] The fixed support includes a right-angle adapter, a breadboard, a Z-axis single-axis displacement stage, a fixing block, a frame, a pole, a wire fixing support, and a Y-axis single-axis displacement stage;

[0019] The upper electromagnetic coil is mounted on the upper end of the frame via the upper vertical pole, and the lower electromagnetic coil is mounted vertically opposite to the upper electromagnetic coil via the lower frame via the lower vertical pole. The frame is mounted on the Z-axis single-axis displacement stage on the right side via fixing blocks and bolts. The Z-axis single-axis displacement stage is mounted on the upper end of the breadboard via bolts, and the lower end of the breadboard is fixed to the working base plate via a right-angle adapter. The length of the first energized wire in the magnetic field is not less than 38mm. The energized wire is fixed in the middle position of the two electromagnetic coils via a horizontally placed wire fixing bracket. The lower end of the wire fixing bracket is mounted on the Y-axis single-axis displacement stage via bolts, and the lower end of the Y-axis single-axis displacement stage is mounted on the upper surface of the torsion beam.

[0020] Furthermore, the calibration module includes electromagnetic coils arranged opposite each other on the left and right, a second energized wire, and a fixed bracket;

[0021] The fixed support includes a breadboard vertical support, a breadboard, a Z-axis single-axis displacement stage, a right-angle adapter, a fixing block, a frame, a pole, and a wire fixing support;

[0022] One side of the electromagnetic coil is horizontally mounted on the frame via the pole on that side, and the other side of the electromagnetic coil is connected to the frame via the pole. The upper end of the frame is mounted on a suspended right-angle adapter via a fixing block. The right-angle adapter is bolted to the Z-axis single-axis displacement stage on the left side. The Z-axis single-axis displacement stage is bolted to the upper end of the breadboard. The lower end of the breadboard is fixed to the working base plate via a breadboard vertical bracket. The length of the second energized wire in the magnetic field is not less than 38mm. The wire is horizontally fixed in the middle position between the two electromagnetic coils via a vertical wire fixing bracket.

[0023] Furthermore, it also includes an electronic balance that works in conjunction with the calibration module and is located on the same side as the calibration module.

[0024] A method for measurement using the above-described testing system includes the following steps:

[0025] Step (1): Adjust the fine-tuning knob of the adjustment mechanism to make the flexible pivot perpendicular to the working base plate and keep the torsion beam horizontal with the working base plate.

[0026] Step (2): Calibrate the micro-thrust of the micro-thrust testing system;

[0027] Step (21): Calibration of the functional relationship between micro-thrust and current: Zero and calibrate the electronic balance, install the calibration module on the working base plate with bolts, energize the two electromagnetic coils in the calibration module to generate a high-density magnetic field, fix the second energized wire in the middle position of the two electromagnetic coils through the vertical wire fixing block, place the vertical wire fixing block on the electronic balance, pass DC current to the second energized wire, the wire is subjected to the vertical Ampere force in the magnetic field, the gravity changes, the change of gravity is measured by the electronic balance, the change of gravity is the magnitude of micro-thrust, repeat the above operation multiple times, the functional relationship between micro-thrust and current can be obtained;

[0028] Step (22): Calibration of the functional relationship between micro-displacement and current: Fix the micro-thrust generating device to the working base plate with bolts, install the two electromagnetic coils in the micro-thrust generating device on the frame through the polar axis, and make the gap between the two electromagnetic coils the same as the gap between the two electromagnetic coils of the calibration module. Fix the first energized wire to the middle position of the two electromagnetic coils through the horizontal wire fixing block. Fix the horizontal wire fixing bracket to the torsion beam through the single-axis displacement stage. Apply the same DC current to the first energized wire as to the second energized wire to generate the same micro-thrust, so that the torsion beam swings. Measure the relative distance data between the eddy current sensor probe and the side surface of the torsion beam through the eddy current sensor. Repeat the above operation multiple times to obtain the functional relationship between micro-displacement and current.

[0029] Step (23): Fit the functional relationship between micro-thrust and current and the functional relationship between micro-displacement and current obtained in steps (21) and (22) to obtain the functional relationship between micro-thrust and displacement of the micro-thrust test system;

[0030] Step (3): Micro-thrust engine installation: Fix the micro-thrust engine and counterweight to the torsion beam respectively, adjust the single-axis displacement table to make them level, and adjust the fine adjustment knob of the adjustment mechanism in the fixing device again to make the flexible pivot perpendicular to the working base plate and make the torsion beam and the fixed base plate level.

[0031] Step (4): Measurement of micro-thrust of micro-thrust engine: Start micro-thrust engine wirelessly, measure the relative distance between sensor probe and side surface of torsion beam by eddy current sensor, and generate resistance by damping structure to gradually restore torsion beam to equilibrium position. Finally, use the functional relationship between micro-thrust and displacement obtained by step (2) to calculate the value of micro-thrust generated by micro-thrust engine.

[0032] Compared with the prior art, the significant advantages of this invention are:

[0033] The micro-thrust generating device of this invention uses a combination of two identical electromagnetic coils and a current-carrying wire to generate minute thrust. The two identical electromagnetic coils, acting as magnetic poles, are mounted opposite each other to generate a magnetic field. The current-carrying wire is fixed in this magnetic field by a wire fixing block and is energized with direct current. The wire is subjected to an Ampere force, which is the generated minute calibration force. The lower end of the wire fixing block is fixed to a single-axis displacement stage. The position of the wire fixing block can be adjusted by adjusting the displacement stage, ensuring that the working area of ​​the current-carrying wire is in a uniform magnetic field, thus avoiding the influence of magnetic leakage at the edge of the magnetic pole surface on measurement accuracy. Furthermore, this invention can achieve the measurement of millinewton-level micro-thrust in micro-propulsion systems. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the micro-thrust testing system according to the present invention.

[0035] Figure 2 This is a schematic diagram of the torsion beam and the fixing device.

[0036] Figure 3 This is a schematic diagram of the fixing device according to the present invention.

[0037] Figure 4 This is a schematic diagram of the damping structure according to the present invention.

[0038] Figure 5 This is a schematic diagram of the calibration module according to the present invention.

[0039] Figure 6 This is a schematic diagram of the displacement measuring device according to the present invention.

[0040] Figure 7 This is a schematic diagram of the micro-thrust generating device according to the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1-Torsion beam, 2-Flexible pivot, 3-Micro-thrust engine, 4-Counterweight, 5-Fixing device, 6-Micro-thrust generating device, 7-Displacement measuring device, 8-Damping structure, 9-Calibration module, 501-Right-angle fixing block, 502-Optical axis fixing ring, 503-Adjustment mechanism, 504-Support assembly, 601-Electromagnetic coil, 602-First energized wire, 603-Fixing bracket, 701-Eddy current sensor, 702-Fixing bracket, 801-Electromagnet, 802-Damping plate, 803-Single-axis displacement stage, 804-Right-angle fixing block, 805-Optical breadboard, 901-Electromagnetic coil, 902-Second energized wire, 903-Fixing bracket. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings.

[0044] The micro-thrust testing system of the present invention includes a torsion beam 1, a flexible pivot 2, a micro-thrust engine 3, a counterweight 4, a fixing device 5, a micro-thrust generating device 6, a displacement measuring device 7, a damping structure 8, and a calibration module 9.

[0045] The micro-thrust testing system is a torsion pendulum type. All components of the testing system are mounted on a rectangular working base plate. The torsion pendulum beam 1 is placed horizontally above the working base plate in the middle position. The fixing device 5 is installed in the middle of the torsion pendulum beam 1. The damping structure 8 is installed on the working base plate at the same horizontal line as the torsion pendulum beam.

[0046] On the operating platform, from left to right, a displacement measuring device 7 and a fixing device 5 are installed on the working base plate in front of the torsion beam 1 via bolts. From left to right, a micro-thrust generating device 6 and a calibration module 9 are installed on the working base plate behind the torsion beam 1 via bolts.

[0047] The torsion beam 1 is an I-beam, which acts as an actuator and will swing horizontally when a small thrust is applied.

[0048] The micro-thrust engine 3 and the counterweight 4 are mounted on the upper surface of the torsion beam 1 via a single-axis displacement table. The micro-thrust engine 3 is mounted on the left end of the upper surface of the torsion beam, and the counterweight 4 is mounted on the right end of the upper surface of the torsion beam. The single-axis displacement table can adjust the position of the micro-thrust engine 3 and the counterweight 4 to achieve balance between the micro-thrust engine 3 and the counterweight 4.

[0049] The fixing device 5 primarily provides stable support for the torsion beam. It consists of a right-angle fixing block 501, an optical axis fixing ring 502, an adjusting mechanism 503, and a support assembly 504. The right-angle fixing block 501, optical axis fixing ring 502, and support assembly 504 are arranged sequentially from top to bottom on the left side of the device, while the adjusting mechanism 503 is located on the right side. The right-angle fixing block 501 is bolted to the top of the adjusting mechanism 503. The upper optical axis fixing ring 502 is fixed to the left end of the suspended right-angle fixing block 501. The lower optical axis fixing ring 502 faces the upper optical axis fixing ring 502 and is fixed to the working base plate via an adapter plate. The support assembly 504 is located between the two optical axis fixing rings 502 and is bolted to the torsion beam 1 through the flexible pivot mounting holes on the torsion beam. The fixing device is placed on the working base plate, and the torsion beam passes through the support assembly 504 and is suspended by the support 504. The adjustment mechanism 503 is a three-axis precision displacement adjustment platform with adjustment knobs in the X, Y, and Z directions, enabling three-way adjustment.

[0050] The flexible pivot 2 serves as a measuring sensitive element. When the torsion beam swings, the flexible pivot 2 will twist. The flexible pivot 2 passes through the support assembly 504 and is fixed to the torsion beam. Both ends of the flexible pivot 2 are rigidly fixed. The upper end of the flexible pivot 2 is fixed between the adjustment mechanism 503 and the torsion beam 1 through the upper optical axis fixing ring 502 and the right angle fixing ring 501. The lower end of the flexible pivot 2 is fixed between the working base plate and the torsion beam through the lower optical axis fixing ring 502 and the adapter plate.

[0051] The main function of the displacement measuring device 7 is to measure the displacement data of the torsion beam 1 when it deflects. The displacement measuring device consists of an eddy current sensor 701 and a fixed bracket 702 from top to bottom. The eddy current sensor 701 includes an eddy current probe and an adjustment circuit preamplifier. The eddy current probe is mounted on the fixed base plate through the fixed bracket 702. The adjustment circuit preamplifier is placed on the working base plate on the right side of the fixed bracket and connected to an external power supply.

[0052] The main function of the damping structure 8 is to generate resistance on the torsion beam 1, allowing the torsion beam to quickly return to its initial equilibrium position. The damping structure 8 consists of two electromagnets 801 of the same size, a damping plate 802, a right-angle fixing block 803, a single-axis displacement stage 804, and an optical breadboard 805. On the left side of the device, from left to right, are the right-angle fixing block 803, the optical breadboard 805, and the single-axis displacement stage 804. The right-angle fixing block 803 on the left is fixed to the optical breadboard 805 with bolts. On the right side of the device, the right-angle fixing block 803, electromagnets 801, and damping plate 802 are arranged from top to bottom. The upper electromagnet 801 is fixed to the lower surface of the suspended right-angle fixing block 803, and the lower electromagnet 801 is fixed to the working base plate via an adapter block. The damping plate 802 is a copper sheet, with one end located between the two electromagnets and the other end fixed to the lower surface of the I-beam's web plate with bolts.

[0053] The main function of the micro-thrust generating device 6 is to generate a small thrust. It consists of an electromagnetic coil 601, a first energized wire 602, and a fixed bracket 603. From right to left, the right side of the fixed bracket 603 consists of a right-angle adapter, a breadboard, a single-axis displacement stage, a fixing block, a frame, and a pole; the left side, from top to bottom, consists of a wire fixing bracket and the single-axis displacement stage. The upper electromagnetic coil 601 is mounted on the upper end of the frame via the upper vertical pole, and the lower electromagnetic coil 602 is mounted vertically opposite to the upper electromagnetic coil via the lower frame and the lower vertical pole. The frame is mounted on the single-axis displacement stage on the right side via a fixing block and bolts. The single-axis displacement stage is bolted to the upper end of the breadboard, and the lower end of the breadboard is fixed to the working base plate via the right-angle adapter. The length of the first energized conductor 602 in the magnetic field is 38mm. The energized conductor is fixed in the middle position of the two electromagnetic coils 601 by a horizontally placed conductor fixing bracket. The lower end of the conductor fixing bracket is installed on the single-axis displacement stage by bolts. The lower end of the single-axis displacement stage is installed on the upper surface of the torsion beam.

[0054] The primary function of calibration module 9 is to calibrate the micro-thrust testing system. It consists of an electromagnetic coil 901, a second energized wire 902, and a fixed bracket 903. From left to right, the left side of the fixed bracket 903 comprises a breadboard vertical bracket, a breadboard, a single-axis displacement stage, and a right-angle adapter. From top to bottom, the right side comprises a fixing block, a frame, a pole, and a wire fixing bracket. The electromagnetic coil 901 on the left is horizontally mounted on the frame via the left pole, and the electromagnetic coil 901 on the right is horizontally mounted opposite the electromagnetic coil on the left via the pole. The upper end of the frame is mounted on the suspended right-angle adapter via a fixing block. The right-angle adapter is bolted to the single-axis displacement stage on the left side. The single-axis displacement stage is bolted to the upper end of the breadboard, and the lower end of the breadboard is fixed to the working base plate via the breadboard vertical bracket. The second energized wire 902 has a length of 38mm in the magnetic field and is horizontally fixed between the two electromagnetic coils via a vertical wire fixing bracket.

[0055] This invention also discloses a method for measuring the micro-thrust of a micro-thrust engine, the steps of which are as follows:

[0056] 1. Adjust the fine-tuning knob of the adjusting mechanism 503 in the fixing device 5 so that the flexible pivot 2 is perpendicular to the working base plate and the torsion beam 1 is kept horizontal with the working base plate;

[0057] 2. Calibrate the micro-thrust of the micro-thrust testing system;

[0058] The calibration steps are as follows:

[0059] (1) Calibration of the relationship between micro-thrust and current: The precision electronic balance is mainly used to measure the value of the generated micro-thrust. The electronic balance is installed close to the calibration module on the working base plate on the same side as the calibration module. First, the precision electronic balance is zeroed and calibrated. The calibration module 9 is installed on the working base plate with bolts. The two electromagnetic coils 901 in the calibration module 9 are energized to generate a high-density magnetic field. The second energized wire 902 is fixed in the middle position of the two electromagnetic coils 901 through the vertical wire fixing block. The vertical wire fixing block is placed on the precision electronic balance. Direct current is applied to the second energized wire 902. The wire is subjected to the vertical Ampere force in the magnetic field. The gravity will change. The change in gravity is measured by the precision electronic balance. The change in gravity is the magnitude of the micro-thrust. By repeating the above operation multiple times, the functional relationship between the micro-thrust and the current can be obtained.

[0060] (2) Calibration of the functional relationship between micro-displacement and current: The micro-thrust generating device is fixed to the working base plate with bolts. The two electromagnetic coils 601 in the micro-thrust generating device 6 are mounted on the frame through the polar axis, and the gap between the two electromagnetic coils 601 is the same as the gap between the two electromagnetic coils 901 in (1) above. The current-carrying wire 602 is fixed to the middle position of the two electromagnetic coils 601 through the horizontal wire fixing block. The horizontal wire fixing bracket is fixed to the torsion beam 1 through the single-axis displacement stage. The same DC current as the current-carrying wire 901 in (1) above is applied to the current-carrying wire 601 to generate the same micro-thrust, so that the torsion beam 1 swings. The relative distance data between the eddy current sensor probe and the side surface of the torsion beam 1 is measured by the eddy current sensor 701. By repeating the above operation multiple times, the functional relationship between micro-displacement and current can be obtained.

[0061] (3) Fit the functional relationship between micro-thrust and current and the functional relationship between micro-displacement and current obtained in steps (1) and (2) to obtain the functional relationship between micro-thrust and displacement of the micro-thrust test system.

[0062] 3. Installation of micro-thrust engine: Fix the micro-thrust engine 3 and the counterweight 4 on the torsion beam 1 respectively. Adjust the single-axis displacement table to make them level. Adjust the fine-tuning knob of the adjustment mechanism in the fixing device 5 again to make the flexible pivot 2 perpendicular to the working base plate and to keep the torsion beam 1 and the fixed base plate horizontal.

[0063] 4. Measurement of micro-thrust of micro-thrust engine 3: Micro-thrust engine 3 is started wirelessly. The relative distance between the sensor probe and the side surface of the torsion beam 1 is measured by the eddy current sensor 701. The resistance generated by the damping structure 8 causes the torsion beam 1 to gradually return to the equilibrium position. Finally, the value of micro-thrust generated by micro-thrust engine 3 can be calculated by using the functional relationship between micro-thrust and displacement obtained in step 2 above.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of measurement with a micro-thrust test system of the torsional pendulum type, characterized in that, The torsional pendulum type micro-thrust test system comprises a working base plate and a torsional pendulum beam (1), a flexible pivot (2), a micro-thrust engine (3), a counterweight (4), a fixing device (5), a micro-thrust generating device (6), a displacement measuring device (7), a damping structure (8) and a calibration module (9) arranged on the working base plate; the torsional pendulum beam (1) is suspended on the working base plate by the fixing device (5), and the micro-thrust engine (3) and the counterweight (4) are arranged at two ends of the upper surface of the torsional pendulum beam through a single-axis displacement platform; the damping structure (8) is installed on the working base plate in the same horizontal line as the torsional pendulum beam, generates an electromagnetic resistance to stop the horizontal swing of the torsional pendulum beam, and provides a required damping ratio for measurement; the micro-thrust generating device (6) is installed on the working base plate on one side of the torsional pendulum beam, and is combined by two oppositely arranged electromagnetic coils and current-carrying wires to generate a small thrust; the displacement measuring device (7) is installed on the working base plate on the opposite side of the torsional pendulum beam and the micro-thrust generating device (6), and the relative distance data between the displacement measuring device (7) and the side surface of the torsional pendulum beam are measured by an eddy current displacement sensor; and the calibration module (9) is installed on the working base plate on the same side as the micro-thrust generating device, and is used for calibrating the function relationship between the small thrust and the current. The method comprises the following steps: Step (1): adjust the fine adjustment knob of the adjusting mechanism (503) to make the flexible pivot (2) perpendicular to the working base plate and make the torsional pendulum beam (1) horizontal to the working base plate; Step (2): calibrate the micro-thrust of the micro-thrust test system; Step (21): calibrate the function relationship between the small thrust and the current: zero and calibrate the electronic balance, install the calibration module (9) on the working base plate through bolts, generate a high-density magnetic field by electrifying the two second electromagnetic coils (901) in the calibration module (9), fix the second current-carrying wire (902) in the middle position between the two second electromagnetic coils (901) through a vertical wire fixing block, place the vertical wire fixing block on the electronic balance, electrify the second current-carrying wire (902) with direct current, the wire is subjected to vertical ampere force in the magnetic field, the gravity changes, the change value of the gravity is measured by the electronic balance, and the change value of the gravity is the size of the micro-thrust, and the function relationship between the small thrust and the current can be obtained by performing the above operation multiple times. Step (22): micro-displacement and current function relationship calibration: the micro-thrust generating device is fixed on the working base plate through bolts, the two first electromagnetic coils (601) in the micro-thrust generating device are installed on the frame through the pole shaft, and the gap of the two first electromagnetic coils (601) is the same as that of the two second electromagnetic coils (901) of the calibration module, the first current-carrying wire (602) is fixed in the middle position of the two first electromagnetic coils (601) through the horizontal wire fixing block, and the horizontal wire fixing support is fixed on the torsional beam through the single-axis displacement table; the same micro-thrust is generated by applying the same direct current to the first current-carrying wire (602) as the second current-carrying wire (902), so that the torsional beam swings, and the relative distance data between the eddy current sensor probe and the side surface of the torsional beam is measured by the eddy current sensor (701); the above operation is performed multiple times, and the function relationship between the micro-displacement and the current can be obtained. Step (23): fitting the function relationship between the micro-thrust and the current obtained in steps (21) and (22) and the function relationship between the micro-displacement and the current to obtain the function relationship between the micro-thrust and the displacement of the micro-thrust test system. Step (3): micro-thrust engine installation: the micro-thrust engine (3) and the counterweight (4) are fixed on the torsional beam respectively, the single-axis displacement table is adjusted to balance them, and the fine adjustment knob of the adjusting mechanism in the fixing device (5) is adjusted again to make the flexible pivot (2) perpendicular to the working base plate and make the torsional beam (1) horizontal to the fixed base plate. Step (4): micro-thrust measurement of the micro-thrust engine: the micro-thrust engine (3) is started by wireless mode, the relative distance data between the sensor probe and the side surface of the torsional beam (1) is measured by the eddy current sensor (701), and the resistance is generated by the damping structure (8) to make the torsional beam gradually return to the balance position, and finally the function relationship between the micro-thrust and the displacement obtained in step (2) is used to calculate the value of the micro-thrust generated by the micro-thrust engine (3).

2. The method of claim 1, wherein, The torsional beam is an I-shaped beam, and the torsional beam is an execution component which will swing horizontally when the micro-thrust acts.

3. The method of claim 2, wherein, The flexible pivot (2) is used as a measurement sensitive element, which twists when the torsional beam swings; the flexible pivot (2) is fixed relative to the torsional beam, and the two ends of the flexible pivot are rigidly fixed.

4. The method of claim 3, wherein, The fixing device (5) includes a first right-angle fixing block (501), an optical axis fixing ring (502), an adjusting mechanism (503), and a support assembly (504). The first right-angle fixing block (501) is fixed on the upper top end of the adjusting mechanism (503), the support assembly (504) passes through the corresponding through hole of the torsional beam and is fixedly connected with the torsional beam, the support assembly (504) is provided with a through hole for the flexible pivot (2) to pass through, the flexible pivot and the support assembly are connected and cannot move relative to each other, the upper and lower ends of the flexible pivot (2) are connected with the adapter plate through the optical axis fixing ring and the first right-angle fixing block (501) respectively; the adjusting mechanism (503) is a three-axis displacement adjusting platform.

5. The method of claim 4, wherein, The displacement measuring device (7) comprises, from top to bottom, an eddy current sensor (701) and a second fixed support (702); The eddy current sensor (701) comprises an eddy current probe and an adjustment circuit preamplifier, the eddy current probe is installed on the fixed bottom plate through the second fixed support (702), and the adjustment circuit preamplifier is placed on the working bottom plate on one side of the fixed support and connected with an external power supply.

6. The method of claim 5, wherein, The damping structure (8) comprises two same-scale electromagnets (801) arranged oppositely, a damping sheet (802) arranged at one end between the two electromagnets, a second right-angle fixed block (803), a Z-direction single-axis displacement table (804) and an optical face breadboard (805); The second right-angle fixed block (803) is fixed on the optical face breadboard (805) through bolts, the upper electromagnet (801) is fixed on the lower surface of the suspended second right-angle fixed block (803), and the lower electromagnet (801) is fixed on the working bottom plate through an adapter block; The other end of the damping sheet is fixedly connected with the lower surface of the waist plate of the I-shaped beam.

7. The method of claim 6, wherein, The micro-thrust generating device (6) comprises first electromagnets (601) arranged oppositely, a first power supply wire (602) and a first fixed support (603); The first fixed support (603) comprises a right-angle adapter, a breadboard, a Z-direction single-axis displacement table, a fixed block, a frame, a pole, a wire fixed support and a Y-direction single-axis displacement table; The upper first electromagnet is installed on the upper end of the frame through the vertical pole on the upper side, the lower first electromagnet is installed vertically opposite to the upper electromagnet through the vertical pole on the lower side and the frame on the lower side, the frame is installed on the Z-direction single-axis displacement table through the fixed block and the bolts on the right side, the Z-direction single-axis displacement table is installed on the upper end of the breadboard through the bolts, and the lower end of the breadboard is fixed on the working bottom plate through the right-angle adapter; the length of the first power supply wire (602) in the magnetic field is not less than 38 mm, the power supply wire is fixed in the middle position between the two first electromagnets (601) through the horizontally arranged wire fixed support, the lower end of the wire fixed support is installed on the Y-direction single-axis displacement table through the bolts, and the lower end of the Y-direction single-axis displacement table is installed on the upper surface of the torsion beam.

8. The method of claim 7, wherein, The calibration module (9) comprises second electromagnets (901) arranged oppositely, a second power supply wire (902) and a third fixed support (903); The third fixed support (903) comprises a breadboard vertical support, a breadboard, a Z-direction single-axis displacement table, a right-angle adapter, a fixed block, a frame, a pole, a wire fixed support; One side of the second electromagnet is horizontally installed on the frame through the pole on the side, and the other side of the second electromagnet is connected with the frame through the pole; the upper end of the frame is installed on the suspended right-angle adapter through the fixed block, the right-angle adapter is installed on the Z-direction single-axis displacement table through the bolts on the left side, the Z-direction single-axis displacement table is fixed on the upper end of the breadboard through the bolts, the lower end of the breadboard is fixed on the working bottom plate through the breadboard vertical support, the length of the second power supply wire (902) in the magnetic field is not less than 38 mm, and the wire is horizontally fixed in the middle position between the two electromagnets through the vertical wire fixed support.

9. The method of claim 8, wherein, The calibration module is used in cooperation with an electronic balance. The calibration module is used in cooperation with an electronic balance.

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