An integrated weak force measurement device and method with strong differential measurement

Abstract

This invention discloses a strongly differential integrated micro-force measurement device, including a first sensitive platform, a leveling base, a load-bearing frame, a second sensitive platform, a first displacement sensor, a first feedback control actuator, a second displacement sensor, and a second feedback control actuator. It also discloses a micro-force measurement method. This invention constructs two nested sets of identical sensitive platforms for micro-force testing. The first sensitive platform is used to detect environmental noise such as structural deformation, residual airflow disturbance, and ground micro-vibration. The second sensitive platform detects the micro-thrust to be measured while simultaneously measuring the environmental noise. By subtracting the common-mode environmental noise from the measured value of the second sensitive platform, a high-precision thrust signal is obtained.

Description

Technical Field

[0001] This invention belongs to the field of precision inertial device testing technology, specifically relating to a strong differential integrated weak force measurement device and a weak force measurement method. Background Technology

[0002] With the rapid development of aerospace technology, various satellites are being launched into orbit to undertake different exploration missions. Spaceborne micro-thrusters are the foundation for micro and nano satellites to achieve precise attitude control, orbit control, and rapid maneuvering. As near-Earth satellite constellations and deep space exploration accelerate, the demand for high-performance thrusters has increased significantly. To ensure their performance in the space environment, it is necessary to conduct detailed performance tests on these micro-thrusters on the ground.

[0003] On the ground, in addition to considering the pressure fluctuations of the working fluid in the thruster and the test interference caused by the thruster itself, such as valve movement, it is also necessary to consider the influence of environmental fluctuations on the thruster and thrust test bench, such as the solid tidal effect of ground tilt, ground micro-vibration, ambient temperature, electromagnetic field fluctuations, etc., which makes high-precision testing and calibration of thrust extremely difficult.

[0004] To meet the needs of micro-thrust testing, scholars at home and abroad have studied various thrust test stands with different configurations, such as torsion pendulum, balance, and suspension pendulum. Internationally, typical high-precision test stands include the classic torsion pendulum with suspension wire designed by NASA in 2002 for ground testing of micro-thrusters in the LISA project; the torsion pendulum test stand with horizontal rotation developed by Photonic Associates in the United States in 2005, which achieved a test resolution of 0.03 μN with a measurement bandwidth of 0.1 Hz; domestically, in 2012, Huazhong University of Science and Technology developed a special suspended vertical axis torsion pendulum to test pulsed plasma thrusters, achieving a thrust measurement resolution of 0.09 μN; in 2018, the Institute of Mechanics of the Chinese Academy of Sciences and in 2021, Beijing University of Aeronautics and Astronautics respectively developed micro-thrust test stands based on the principle of vertical axis horizontal torsion pendulum, with a measurement range of about 200-400 μN and a resolution of 0.1 μN; in 2020, Sun Yat-sen University and the Institute of Precision Measurement of the Chinese Academy of Sciences built a test stand with a balanced vertical torsion pendulum and other weak force sensitive configurations, achieving a measurement level of significantly better than 0.1 μN for testing actual thrusters at the kilogram level. Among the aforementioned test benches, some employ structural designs and technical means that can suppress common-mode noise based on their own principles. However, they are usually limited by the insufficient similarity and consistency of sensitive structures, making it difficult to achieve a suppression of environmental common-mode noise of more than 20dB.

[0005] In higher-precision weak force testing, the common-mode noise suppression capability still needs to be further improved, especially in the low-frequency and high-frequency bands where the test noise approaches or even significantly exceeds the test requirements, requiring new technical means to achieve a breakthrough. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned problems in the prior art by providing a strongly differential integrated weak force measurement device and a weak force measurement method.

[0007] The above-mentioned objectives of the present invention are achieved by the following technical means:

[0008] An integrated micro-force measurement device with strong differential force includes a first sensitive stage, a leveling base, a load-bearing frame, and a second sensitive stage. The load-bearing frame is mounted on the leveling base. The first sensitive stage is connected to the load-bearing frame via multiple sets of first wire-drawing constraint groups. The second sensitive stage is connected to the load-bearing frame via multiple sets of second wire-drawing constraint groups. The first and second sensitive stages are nested together. A first micro-pusher is mounted on the first sensitive stage, and a second micro-pusher is mounted on the second sensitive stage. The load-bearing frame includes a pair of load-bearing plates, both mounted on the leveling base. The load-bearing plates have the same set thickness, and the number of load-bearing plates is the same as the number of first wire-drawing constraint groups. Each load-bearing plate is connected to the first sensitive stage via a set of first wire-drawing constraint groups. The first sensitive stage is fixedly connected to the same side of the corresponding load-bearing plate via each first wire-drawing constraint group. Each load-bearing plate is connected to the second sensitive stage via a set of second wire-drawing constraint groups. The second sensitive stage is fixedly connected to the other side of the corresponding load-bearing plate via each second wire-drawing constraint group.

[0009] It also includes a first feedback control component, which includes a first displacement sensor and a first feedback control actuator. The first displacement sensor is disposed on the first sensitive stage, and the first feedback control actuator includes a first conductor and a first magnet. The first magnet is fixed on the support frame, and the first conductor is disposed on the first sensitive stage.

[0010] It also includes a second feedback control component, which includes a second displacement sensor and a second feedback control actuator. The second displacement sensor is disposed on the second sensitive stage, and the second feedback control actuator includes a second conductor and a second magnet. The second magnet is fixed on the support frame, and the second conductor is disposed on the second sensitive stage.

[0011] As described above, the first sensitive platform includes a pair of parallel first end face frames. Each first end face frame is fixedly connected by multiple first horizontal connecting rods along the axial direction. The multiple first horizontal connecting rods are evenly distributed along the circumferential direction of the first sensitive platform. Each first end face frame is connected to a corresponding load-bearing plate through a set of first wire-drawing constraint groups. The first sensitive platform also includes a first support plate arranged perpendicular to the axial direction. Both ends of the first support plate are fixedly connected to the first horizontal connecting rods at the same height. A first micro-pusher is fixed on the first support plate. Multiple first fixing holes with the same spacing are arranged circumferentially on the first end face frames. The first horizontal connecting rods are connected to the first end face frames through the first fixing holes.

[0012] The second sensitive platform includes a pair of parallel second end face frames, each of which is fixedly connected by multiple second horizontal connecting rods along the axial direction. The multiple second horizontal connecting rods are evenly distributed along the circumferential direction of the second sensitive platform. Each second end face frame is connected to a corresponding load-bearing plate through a set of second wire-drawing constraint groups. The second sensitive platform also includes a second support plate arranged perpendicular to the axial direction. Both ends of the second support plate are fixedly connected to the second horizontal connecting rods at the same height. A second micro-pusher is fixed on the second support plate. Multiple second fixing holes with equal intervals are arranged circumferentially on the second end face frames. The second horizontal connecting rods are connected to the second end face frames through the second fixing holes.

[0013] The first horizontal connecting rod and the second horizontal connecting rod are staggered.

[0014] As described above, the first wire-drawing constraint group includes a first adjustment component and multiple first fixed wires of the same length. One end of the first fixed wire is fixed to the first sensitive platform, and the other end of the first fixed wire is fixed to the load-bearing frame. The fixing points of all the first fixed wires on the first sensitive platform are evenly distributed on the same circumference, and the fixing points of all the first fixed wires on the load-bearing frame are evenly distributed on the same circumference.

[0015] One of the first fixed wires is vertical, and the first adjustment component is symmetrically arranged on both sides of the first sensitive stage body with the first fixed wire in the vertical direction. All the first fixed wires are coplanar and perpendicular to the axial direction of the first sensitive stage body.

[0016] As described above, the first adjustment assembly includes a first adjustment wire, a first fixed pulley, a weight, and a first spring. One end of the first adjustment wire is fixed to the first sensitive platform, and the fixing point of the first adjustment wire on the first sensitive platform is symmetrical to the fixing point of the first fixed wire in the vertical direction on the first sensitive platform. The first fixed pulley is fixed to the support frame, and the other end of the first adjustment wire passes through the first fixed pulley and is hung with a weight. The first fixed pulley is located directly above the fixing point of the first adjustment wire on the first sensitive platform, so that the first adjustment wire is also in the vertical direction. The first adjustment wire and the first fixed wire are coplanar. The second spring is disposed on the second adjustment wire.

[0017] As described above, the second wire-drawing constraint group includes a second adjustment component and multiple second fixed wires of the same length. One end of the second fixed wire is fixed to the second sensitive platform, and the other end of the second fixed wire is fixed to the load-bearing frame. The fixing points of all the second fixed wires on the second sensitive platform are evenly distributed on the same circumference.

[0018] One of the second fixed wires is vertical. The second adjustment component is symmetrically arranged on both sides of the second sensitive stage with the vertical second fixed wire. All the second fixed wires are coplanar and perpendicular to the axial direction of the second sensitive stage.

[0019] As described above, the second adjustment assembly includes a second adjustment wire, a second fixed pulley, a weight, and a second spring. One end of the second adjustment wire is fixed to the second sensitive platform, and the fixing point of the second adjustment wire on the second sensitive platform is symmetrical to the fixing point of the vertically oriented second fixed wire on the second sensitive platform. The second fixed pulley is fixed to the support frame, and the other end of the second adjustment wire passes through the second fixed pulley and is hung with a weight. The second fixed pulley is located directly above the fixing point of the second adjustment wire on the second sensitive platform, so that the second adjustment wire is also vertical. The second adjustment wire and the second fixed wire are coplanar. The second spring is disposed on the second adjustment wire.

[0020] A method for measuring weak forces, utilizing an integrated weak force measuring device with strong differential as described above, includes the following steps:

[0021] Step 1: Measure the interference force F generated by ambient noise using the first sensitive platform. 干扰 ;

[0022] Step 2: Measure the force F to be measured using the second sensitive stage. 待测 +Interference force generated by environmental noise F 干扰 The resultant force F 合力 ;

[0023] Step 3, the force to be measured F 待测 Equal to the resultant force F合力 Subtract the interference force F 干扰 .

[0024] As described above, the interference force F generated by environmental noise is measured using the first sensitive stage. 干扰 Specifically:

[0025] The displacement x1 of the first sensitive stage relative to its initial position in the axial direction is measured by the first displacement sensor under the action of the disturbance force, and the velocity of the first sensitive stage is calculated based on the measured displacement x1 of the first sensitive stage relative to its initial position in the axial direction. and the acceleration of the first sensitive platform The interference force is then calculated using the following formula:

[0026]

[0027] In the formula, M1, C1, and K1 are all first open-loop calibration coefficients, M1 is the first mass, C1 is the first damping coefficient, and K1 is the first elastic coefficient;

[0028] The interference force F generated by the measured force plus environmental noise is measured through the second sensitive stage. 干扰 The resultant force F 合力 Specifically:

[0029] The second micro-thruster applies the force to be measured to the second sensitive stage. The second displacement sensor measures the axial displacement x2 of the second sensitive stage relative to its initial position under the combined force of the force to be measured and the disturbance force. The velocity of the second sensitive stage is calculated based on the measured axial displacement x2 relative to its initial position. acceleration of the second sensitive platform The resultant force of the measured force and the interfering force is then calculated using the following formula:

[0030]

[0031] In the formula, M2, C2, and K2 are all second open-loop calibration coefficients, M2 is the second mass, C2 is the second damping coefficient, and K2 is the second elastic coefficient.

[0032] As described above, the interference force F generated by environmental noise is measured using the first sensitive stage. 干扰 Specifically:

[0033] A current is passed through the first conductor. The magnitude of the current in the first conductor is adjusted based on the displacement change of the first sensitive stage in the axial direction relative to its initial position, as measured by the first displacement sensor, so that the displacement measured by the first displacement sensor is 0. The magnetic force F3 exerted by the first magnet on the second sensitive stage and the interference force F exerted by the environmental noise on the second sensitive stage are...干扰 If the magnitudes are equal, the interference force generated by environmental noise is calculated using the following formula:

[0034] F 干扰 =F3=-k c1 I1

[0035] In the formula, k c1 I1 is the first closed-loop calibration coefficient, and I1 is the current flowing into the first conductor.

[0036] The interference force F generated by the measured force plus environmental noise is measured through the second sensitive stage. 干扰 The resultant force F 合力 Specifically:

[0037] The second micro-thruster applies the force to be measured to the second sensitive stage, and a current is passed through the second conductor. Based on the displacement change of the second sensitive stage in the axial direction relative to its initial position measured by the second displacement sensor, the magnitude of the current in the second conductor is adjusted so that the displacement measured by the second displacement sensor is zero. The magnitude of the magnetic force F4 applied by the second magnet to the second sensitive stage is equal to the force F applied by the second micro-thruster. 待测 The interference force F exerted by environmental noise on the second sensitive platform 干扰 The resultant force F 合力 If the magnitudes are equal, the resultant force of the force to be measured plus the interfering force is calculated using the following formula:

[0038] F 合力 =F4=-k c2 I2

[0039] In the formula, k c2 I2 is the second closed-loop calibration coefficient, and I2 is the current flowing into the second conductor.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] This invention constructs two nested, identically designed sensitive platforms for weak force testing. The first sensitive platform is used to detect environmental noise such as structural deformation, residual airflow disturbance, and ground micro-vibration. The second sensitive platform detects the micro-thrust to be measured while also measuring the environmental noise. By subtracting the common-mode environmental noise from the measurement value of the second sensitive platform, a high-precision thrust signal to be measured is obtained. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure connecting the load-bearing frame, the first sensitive platform, and the second sensitive platform of the present invention.

[0043] Figure 2 This is a schematic diagram of the device of the present invention;

[0044] Figure 3 This is a schematic diagram of the structure of one of the sensing platforms (the first sensing platform or the second sensing platform) of the present invention;

[0045] Figure 4 This is a schematic diagram of the open-loop measurement of the present invention;

[0046] Figure 5 This is a schematic diagram of the closed-loop measurement of the present invention;

[0047] Figure 6 This is a schematic diagram showing the connection between one of the sensitive platforms and the corresponding calibration ball and motion displacement platform of the present invention.

[0048] Figure labels and corresponding component names:

[0049] 1-Leveling base; 2-Bearing plate; 3-First wire drawing constraint group; 4-Second wire drawing constraint group; 5-First sensitive stage; 6-Second sensitive stage 2; 7-First micro-thruster; 8-Second micro-thruster; 9-Controller; 10-Signal cable; 11-First horizontal connecting rod; 12-Second horizontal connecting rod; 13-Calibration ball; 14-Motion displacement stage; 15-First end face frame; 16-Second end face frame. Detailed Implementation

[0050] To facilitate understanding and implementation of the present invention by those skilled in the art, the present invention will be further described in detail below with reference to embodiments. The embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0051] Example 1:

[0052] An integrated micro-force measurement device with strong differential force includes a leveling base 1, a support frame, a columnar first sensitive stage 5, a columnar second sensitive stage 6, a first micro-thruster 7, a first feedback control component, a second micro-thruster 8, and a second feedback control component. The support frame is mounted on the leveling base 1. The first sensitive stage 5 is connected to the support frame via multiple sets of first wire-drawing constraint groups 3. The first micro-thruster 7 is mounted on the first sensitive stage 5. The first wire-drawing constraint groups 3 constrain the translational and rotational movements of the first sensitive stage 5 in the vertical direction and in the horizontal direction perpendicular to the axial direction of the first sensitive stage 5. The first sensitive platform 5 can translate or rotate in the axial direction, and the first micro-pusher 7 can push the first sensitive platform 5 to move in the axial direction; the second sensitive platform 6 is connected to the load-bearing frame through multiple sets of second wire-drawing constraint groups 4, and the second micro-pusher 8 is set on the second sensitive platform 6. The second wire-drawing constraint group 4 restricts the translational and rotational degrees of freedom of the second sensitive platform 6 in the vertical direction and the horizontal direction perpendicular to the axial direction of the second sensitive platform 6. The second sensitive platform 6 can translate or rotate in the axial direction, and the second micro-pusher 8 can push the second sensitive platform 6 to move in the axial direction.

[0053] The load-bearing frame includes a pair of parallel U-shaped load-bearing plates 2, both of which are mounted on the leveling base 1. The load-bearing plates 2 have the same set thickness, and the number of load-bearing plates 2 is the same as the number of the first wire-drawing constraint groups 3. Each load-bearing plate 2 is connected to a first sensitive platform 5 via a set of first wire-drawing constraint groups 3. The first sensitive platform 5 is fixedly connected to the same side of the corresponding load-bearing plate 2 via each set of first wire-drawing constraint groups 3. Each load-bearing plate 2 is connected to a second sensitive platform 6 via a set of second wire-drawing constraint groups 4. The second sensitive platform 6 is fixedly connected to the other side of the corresponding load-bearing plate 2 via each set of second wire-drawing constraint groups 4. Therefore, the first sensitive platform 5 and the second sensitive platform 6 are nested and staggered, not affecting each other's axial movement. This results in a millimeter-level distance between the first sensitive platform 5 and the second sensitive platform 6, equal to the set thickness of the load-bearing plates 2, thus ensuring that they do not affect each other's axial movement.

[0054] It also includes a first feedback control component, which includes a first displacement sensor and a first feedback control actuator. The first displacement sensor is disposed on the first sensitive stage 5, and the first feedback control actuator includes a first conductor and a first magnet. The first magnet is fixed on the support frame, and the first conductor is disposed on the first sensitive stage 5.

[0055] The electrical signal applied to the first conductor generates a feedback force in the magnetic field generated by the first magnet, which is used to provide negative feedback on the displacement of the first sensitive stage 5, so that the first sensitive stage 5 is stabilized at the initial position, at which time the displacement sensor measures 0.

[0056] It also includes a second feedback control component, which includes a second displacement sensor and a second feedback control actuator. The second displacement sensor is mounted on the second sensitive stage 6, and the second feedback control actuator includes a second conductor and a second magnet. The second magnet is fixed on the support frame, and the second conductor is mounted on the second sensitive stage 6. The second position sensor measures the displacement change of the second sensitive stage 6 and converts the displacement change into an electrical signal, which is transmitted to the second conductor. The electrical signal applied to the second conductor generates a feedback force in the magnetic field generated by the second magnet, which is used to provide negative feedback on the displacement of the second sensitive stage 6, so that the second sensitive stage 6 is stabilized at the initial position. At this time, the displacement measured by the displacement sensor is 0.

[0057] In one possible implementation, a first fixed rod is provided on the first sensitive stage 5 along the axial direction. The first magnet is a permanent magnet, denoted as the first permanent magnet, and the conductor is a coil, denoted as the first coil. The first permanent magnet is fixed on the support frame, and the first coil is wound and fixed on the first fixed rod. When the first sensitive stage 5 moves along the axial direction, the first permanent magnet drives the first coil to move in the opposite direction, thereby stabilizing the first sensitive stage 5 in the initial position. A second fixed rod is provided on the second sensitive stage 6 along the axial direction. The second magnet is a permanent magnet, denoted as the second permanent magnet, and the conductor is a coil, denoted as the second coil. The second permanent magnet is fixed on the support frame, and the second coil is wound and fixed on the second fixed rod. When the second sensitive stage 6 moves along the axial direction, the second permanent magnet drives the second coil to move in the opposite direction, thereby stabilizing the second sensitive stage 6 in the initial position.

[0058] The first wire-drawing constraint group 3 includes a first adjustment component and multiple first fixed wires of the same length. One end of the first fixed wire is fixed on the first sensitive platform 5, and the other end of the first fixed wire is fixed on the load-bearing frame. The fixing points of all the first fixed wires on the first sensitive platform 5 are evenly distributed on the same circumference, and the fixing points of all the first fixed wires on the load-bearing frame are evenly distributed on the same circumference.

[0059] One of the first fixed wires is vertical, and the first adjustment components are symmetrically arranged on both sides of the first sensitive platform 5 with the first fixed wire in the vertical direction;

[0060] All the first fixed wires are coplanar and perpendicular to the axial direction of the first sensitive platform 5;

[0061] The first adjustment assembly includes a first adjusting wire, a first fixed pulley, and a first spring. One end of the first adjusting wire is fixed to the first sensitive platform 5, and the fixing point of the first adjusting wire on the first sensitive platform 5 is symmetrical to the fixing point of the first fixed wire in the vertical direction on the first sensitive platform 5 (symmetrical about the vertical central axis of the cross-section of the first sensitive platform 5). The first fixed pulley is fixed to the load-bearing frame. The other end of the first adjusting wire passes through the first fixed pulley and a weight of appropriate weight is hung on it. The first fixed pulley is located directly above the fixing point of the first adjusting wire on the first sensitive platform 5, so that the first adjusting wire is also in the vertical direction. The weight can also be replaced with other weights of appropriate weight. The first adjusting wire and the first fixed wire are coplanar.

[0062] The first adjustment component also includes a first spring, which is disposed on the first adjustment wire.

[0063] The second sensitive platform 6 is also connected to the load-bearing frame in the same way via the second wire-reinforcing restraint group 4, specifically:

[0064] The second wire restraint group 4 includes a second adjustment component and multiple second fixed wires of the same length. One end of each second fixed wire is fixed to the second sensitive platform 6, and the other end is fixed to the support frame. The fixing points of all the second fixed wires on the second sensitive platform 6 are evenly distributed on the same circumference. One of the second fixed wires is vertical. The second adjustment component is symmetrically arranged on both sides of the second sensitive platform 6 with the vertical second fixed wire.

[0065] All the second fixed wires are coplanar and perpendicular to the axial direction of the second sensitive platform 6;

[0066] The second adjustment assembly includes a second adjusting wire, a second fixed pulley, and a second spring. One end of the second adjusting wire is fixed to the second sensitive platform 6, and the fixing point of the second adjusting wire on the second sensitive platform 6 is symmetrical to the fixing point of the vertically fixed wire on the second sensitive platform 6 (symmetrical about the vertical central axis of the cross-section of the second sensitive platform 6). The second fixed pulley is fixed to the support frame. The other end of the second adjusting wire passes through the second fixed pulley and a weight of appropriate weight is hung on it. The second fixed pulley is located directly above the fixing point of the second adjusting wire on the second sensitive platform 6, so that the second adjusting wire is also vertical. The weight can also be replaced with other weights of appropriate weight. The second adjusting wire and the second fixed wire are coplanar.

[0067] The second adjustment assembly also includes a second spring, which is disposed on the second adjustment wire.

[0068] In this embodiment, two sets of first wire-drawing constraint groups 3 and two sets of second wire-drawing constraint groups 4 are included. The first sensitive platform 5 includes a pair of parallel first end face frames 15, and the second sensitive platform 6 includes a pair of parallel second end face frames 16. The two end face frames of the first sensitive platform 5 are respectively connected to the load-bearing frame through the two sets of first wire-drawing constraint groups 3 in the manner described above. The two end face frames of the second sensitive platform 6 are respectively connected to the load-bearing frame through the two sets of second wire-drawing constraint groups 4 in the same manner. Each set of first wire-drawing constraint groups 3 includes three first fixed wires, and the included angle between two adjacent first fixed wires is 60°. Each set of second wire-drawing constraint groups 4 includes three second fixed wires, and the included angle between two adjacent second fixed wires is 60°.

[0069] The first sensitive platform 5 and the second sensitive platform 6 of this invention are constrained by eight equal-length draw wires located on two separate planes. The axial translational degree of freedom of the first sensitive platform 5 and the second sensitive platform 6 is the flexible degree of freedom required for micro-thrust testing. When the draw wires are under tension, the translational motion of the platform along the horizontal axis is a flexible degree of freedom. When a micro-thrust is applied in the axial direction of the first sensitive platform 5 and the second sensitive platform 6, the connection point of the two sets of draw wires on one side of the platform moves away from its original surface. Since six of the draw wires (i.e., the first fixed draw wire and the second fixed draw wire) are inextensible, the platform will rotate slightly. The other two draw wires (i.e., the first adjusting draw wire and the second adjusting draw wire) will maintain the tension of the entire elastic structure (approximately) unchanged through the extension of the springs (i.e., the first spring and the second spring) or the slight rotation of the fixed pulleys (i.e., the first fixed pulley and the second fixed pulley). The remaining four degrees of freedom of the platform are directly constrained by the tension of the draw wires. Thus, this invention constructs a sensitive direction suitable for micro-thrust testing along the axial direction.

[0070] Each of the first end face frames 15 of the first sensitive platform 5 is fixedly connected by multiple first horizontal connecting rods 11 along the axial direction. The multiple first horizontal connecting rods 11 are evenly distributed along the circumferential direction of the first sensitive platform 5. Each first end face frame 15 is connected to the corresponding load-bearing plate 2 through a set of first wire-drawing constraint groups 3. The first sensitive platform 5 also includes a first support plate arranged perpendicular to the axial direction. Both ends of the first support plate are fixedly connected to the first horizontal connecting rods 11 at the same height. A first micro-pusher 7 is fixed on the first support plate. Multiple first fixing holes with the same spacing are arranged circumferentially on the first end face frame 15. The first horizontal connecting rods 11 are connected to the first end face frame 15 through the first fixing holes.

[0071] The second sensitive platform 6 has the same structure as the first sensitive platform 5. Specifically, each of the second end face frames 16 of the second sensitive platform 6 is fixedly connected by multiple second horizontal connecting rods 12 along the axial direction. The multiple second horizontal connecting rods 12 are evenly distributed along the circumferential direction of the second sensitive platform 6. Each second end face frame 16 is connected to the corresponding load-bearing plate 2 through a set of second wire-drawing constraint groups 4. The second sensitive platform 6 also includes a second support plate arranged perpendicular to the axial direction. Both ends of the second support plate are fixedly connected to the second horizontal connecting rods 12 at the same height. A second micro-pusher 8 is fixed on the second support plate. Multiple second fixing holes with the same intervals are arranged circumferentially on the second end face frame 16. The second horizontal connecting rods 12 are connected to the second end face frame 16 through the second fixing holes.

[0072] The end face frame (first end face frame 15 or second end face frame 16) can be circular or other regular shapes (such as regular polygons). The number of horizontal connecting rods (first horizontal connecting rod 11 or second horizontal connecting rod 12) can be increased through the fixing holes (first fixing hole or second fixing hole), thereby changing the height of the support plate and thus changing the height of the micro-thruster to adapt to the installation of micro-thrusters or micro-thruster clusters of different masses and volumes.

[0073] The first horizontal connecting rod 11 and the second horizontal connecting rod 12 are staggered, and the first micro-thruster 7 and the second micro-thruster 8 are staggered, so that the movement of the first sensitive stage 5 and the second sensitive stage 6 in the axial direction does not affect each other.

[0074] The leveling base 1 is also equipped with a controller 9, including a first controller and a second controller. The first controller is connected to the first micro-thruster 7 and the first conductor through a signal cable 10, and the second controller is connected to the second micro-thruster 8 and the second conductor through a signal cable 10.

[0075] The invention comprises a first sensitive platform 5 and a first micro-thruster 7, used to detect the total force of structural deformation, residual airflow disturbance, ground micro-vibration, or other environmental noise. Based on this structure, two nested sets of identical sensitive platforms are constructed within the same support structure and workspace. The first set detects environmental noise such as structural deformation, residual airflow disturbance, and ground micro-vibration, while the second set detects the micro-thrust to be measured while simultaneously measuring the environmental noise described in the first set. The system processes the data in real time and subtracts common-mode environmental noise to obtain a high-precision thrust signal. Measured value F test and expected thrust F expect Compare the measurements and evaluate the accuracy by taking into account measurement noise and repeatability.

[0076] Example 2:

[0077] A method for measuring weak forces, utilizing the integrated weak force measuring device with strong differential as described in Example 1, includes the following steps:

[0078] Step 1: Measure the interference force F generated by ambient noise using the first sensitive platform 5. 干扰 ;

[0079] Step 2: Measure the force to be measured plus the interference force F generated by environmental noise through the second sensitive stage 6. 干扰 The resultant force F 合力 ;

[0080] Step 3, the force to be measured F 待测 Equal to the resultant force F 合力 Subtract the interference force F 干扰 .

[0081] This embodiment measures the force to be measured by the second micro-thruster 8 in an open-loop manner, specifically as follows:

[0082] The interference force generated by environmental noise is measured through the first sensitive platform 5, specifically:

[0083] The displacement of the first sensitive platform 5 in the axial direction relative to its initial position is measured by the first displacement sensor. Based on the measured displacement of the first sensitive platform 5 in the axial direction relative to its initial position, the velocity and acceleration of the first sensitive platform 5 are calculated. Then, the disturbance force is calculated using the following formula:

[0084]

[0085] In the formula, x1 represents the axial displacement of the first sensitive platform 5 relative to its initial position under the action of the disturbance force. The speed of the first sensitive platform 5, M1 represents the acceleration of the first sensitive platform 5, C1 and K1 are all first open-loop calibration coefficients, M1 is the first mass (the first mass is the total mass of the first sensitive platform 5, the first micro-thruster 7 and the first support plate), C1 is the first damping coefficient, and K1 is the first elastic coefficient.

[0086] The resultant force of the force to be measured plus the interference force generated by environmental noise is measured through the second sensitive stage 6, specifically:

[0087] The second micro-thruster 8 applies the force to be measured to the second sensitive stage 6. The second displacement sensor measures the axial displacement of the second sensitive stage 6 relative to its initial position under the combined force of the force to be measured and the disturbance force. Based on the measured axial displacement of the second sensitive stage 6 relative to its initial position, the velocity and acceleration of the second sensitive stage 6 are calculated. Finally, the combined force of the force to be measured and the disturbance force is calculated using the following formula:

[0088]

[0089] In the formula, x2 represents the axial displacement of the second sensitive platform 6 relative to its initial position under the action of the disturbance force. The speed of the second sensitive platform 6, M2 is the acceleration of the second sensitive platform 6, C2 and K2 are the second open-loop calibration coefficients, M2 is the second mass (the second mass is the total mass of the second sensitive platform 6, the second micro-thruster 8 and the second support plate), C2 is the second damping coefficient, and K2 is the second elastic coefficient.

[0090] Finally, the force to be measured, F 待测 Equal to the resultant force F 合力 Subtract the interference force F干扰 .

[0091] In this embodiment, the first open-loop calibration coefficient and the second open-loop calibration coefficient are obtained by calibrating the small ball 13 and the one-dimensional motion displacement stage 14;

[0092] The first open-loop calibration coefficient is calibrated in the following way:

[0093] It also includes a first calibration component, which includes a first calibration ball and a one-dimensional first motion displacement stage. The upper end of the first pull line is connected to the first motion displacement stage, and the lower end of the first pull line is connected to the first calibration ball.

[0094] By moving the first motion displacement stage, the first pull wire generates a component force along the axis of the first sensitive stage 5, thereby applying a first standard weak force F1 to the first sensitive stage 5. The first standard weak force F1 is:

[0095]

[0096] In the formula, m1 is the mass of the first calibration ball, g is the gravitational acceleration, x3 is the distance the first motion displacement platform moves, and L1 is the length of the first pull line;

[0097] Then, the displacement of the first sensitive stage 5 in the axial direction relative to its initial position is measured by the first displacement sensor. Based on the measured displacement of the first sensitive stage 5 in the axial direction relative to its initial position, the velocity and acceleration of the first sensitive stage 5 are calculated. The first open-loop calibration coefficients M1, C1, and K1 are then obtained by fitting the following formulas:

[0098]

[0099] Thus, the first open-loop calibration coefficients M1, C1, and K1 are measured.

[0100] The second open-loop calibration coefficient is calibrated in the following way:

[0101] It also includes a second calibration component, which includes a second calibration ball and a one-dimensional second motion displacement stage. The upper end of the second pull line is connected to the second motion displacement stage, and the lower end of the second pull line is connected to the second calibration ball.

[0102] By moving the second motion displacement stage, the second pull wire generates a component force along the axis of the second sensitive stage 6, thereby applying a second standard weak force F1 to the second sensitive stage 6. The second standard weak force F1 is:

[0103]

[0104] In the formula, m2 is the mass of the second calibration ball, x4 is the distance the second motion displacement table moves, and L2 is the length of the second pull line;

[0105] The displacement of the second sensitive stage 6 in the axial direction relative to its initial position is then measured using a second displacement sensor. Based on the measured displacement of the second sensitive stage 6 in the axial direction relative to its initial position, the velocity and acceleration of the second sensitive stage 6 are calculated. The second open-loop calibration coefficients M2, C2, and K2 are then obtained by fitting the data using the following formulas:

[0106]

[0107] Thus, the second open-loop calibration coefficients M2, C2, and K2 were measured.

[0108] Example 3:

[0109] A method for measuring weak forces, utilizing the integrated weak force measuring device with strong differential as described in Example 1, specifically measures the force to be measured generated by the second micro-thruster 8 through closed-loop measurement:

[0110] The interference force generated by environmental noise is measured through the first sensitive platform 5, specifically:

[0111] A current is passed through the first conductor. The magnitude of the current in the first conductor is adjusted based on the displacement change of the first sensitive stage 5 in the axial direction relative to its initial position, as measured by the first displacement sensor. This ensures that the displacement measured by the first displacement sensor is zero, and the first sensitive stage 5 stabilizes at its initial position. This indicates that the magnetic force F3 exerted by the first magnet on the second sensitive stage 6 and the interference force F exerted by the environmental noise on the second sensitive stage 6 are equal. 干扰 If the magnitudes are equal, the interference force generated by environmental noise is calculated using the following formula:

[0112] F 干扰 =F3=-k c1 I1

[0113] In the formula, k c1 I1 is the first closed-loop calibration coefficient, and I1 is the current flowing into the first conductor.

[0114] The resultant force of the force to be measured plus the interference force generated by environmental noise is measured through the second sensitive stage 6, specifically:

[0115] The second micro-thruster 8 applies the force to be measured to the second sensitive stage 6, and a current is passed through the second conductor. Based on the displacement change of the second sensitive stage 6 in the axial direction relative to its initial position measured by the second displacement sensor, the current in the second conductor is adjusted until the displacement measured by the second displacement sensor is zero, and the second sensitive stage 6 stabilizes at its initial position. This indicates that the magnitude of the magnetic force F4 applied by the second magnet to the second sensitive stage 6 is equal to the force F applied by the second micro-thruster 8. 待测 The interference force F exerted by environmental noise on the second sensitive platform 6 干扰 The resultant force F 合力 If the magnitudes are equal, the resultant force of the force to be measured plus the interfering force is calculated using the following formula:

[0116] F 合力 =F4=-k c2 I2

[0117] In the formula, k c2 I2 is the second closed-loop calibration coefficient, and I2 is the current flowing into the second conductor.

[0118] Finally, the force to be measured, F 待测 Equal to the resultant force F 合力 Subtract the interference force F 干扰 .

[0119] The first closed-loop calibration coefficient is calibrated in the following way:

[0120] By moving the first motion displacement stage, the first pull wire generates a component force in the axial direction of the first sensitive stage 5, thereby applying a first standard weak force F1 to the first sensitive stage 5.

[0121] A current is then passed through the first conductor. The magnitude of the current in the first conductor is adjusted based on the displacement change of the first sensitive stage 5 in the axial direction relative to its initial position, as measured by the first displacement sensor. This ensures that the displacement measured by the first displacement sensor is zero, and the first sensitive stage 5 stabilizes at its initial position. This indicates that the magnetic force F3 applied by the first magnet to the second sensitive stage 6 is equal in magnitude to the first standard weak force F1. Therefore, the first closed-loop calibration coefficient k can be obtained by fitting the following formula. c1 :

[0122] F1 = F3 = -k c1 I1

[0123] Thus, the first closed-loop calibration coefficient k was measured. c1 .

[0124] The second closed-loop calibration coefficient is calibrated in the following way:

[0125] By moving the second motion displacement stage, the second pull wire generates a component force in the axial direction of the second sensitive stage 6, thereby applying a second standard weak force F2 to the second sensitive stage 6.

[0126] A current is then passed through the second conductor. The magnitude of the current in the second conductor is adjusted based on the displacement change of the second sensitive stage 6 in the axial direction relative to its initial position, as measured by the second displacement sensor. This ensures that the displacement measured by the second displacement sensor is zero, and the second sensitive stage 6 stabilizes at its initial position. This indicates that the magnetic force F3 applied by the second magnet to the second sensitive stage 6 is equal in magnitude to the second standard weak force F2. Therefore, the second closed-loop calibration coefficient k can be obtained by fitting the following formula. c1 :

[0127] F2 = F4 = -k c2 I2

[0128] Thus, the second closed-loop calibration coefficient k was measured. c2 .

[0129] It should be noted that the embodiments described in this invention are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A strongly differential integrated weak force measurement device, comprising a first sensitive stage (5), characterized in that, It also includes a leveling base (1), a load-bearing frame, and a second sensitive platform (6). The load-bearing frame is set on the leveling base (1). The first sensitive platform (5) is connected to the load-bearing frame through multiple sets of first wire-pulling constraint groups (3). The second sensitive platform (6) is connected to the load-bearing frame through multiple sets of second wire-pulling constraint groups (4). The first sensitive platform (5) and the second sensitive platform (6) are nested together. The first micro-pusher (7) is set on the first sensitive platform (5), and the second micro-pusher (8) is set on the second sensitive platform (6). The load-bearing frame includes a pair of load-bearing plates (2). The load-bearing plates (2) are both set on the leveling base (1). On the ), the load-bearing plates (2) are all of the same set thickness. The number of load-bearing plates (2) is the same as the number of the first wire-drawing constraint group (3). Each load-bearing plate (2) is connected to the first sensitive platform (5) through a set of first wire-drawing constraint group (3). The first sensitive platform (5) is fixedly connected to the same side of the corresponding load-bearing plate (2) through each first wire-drawing constraint group (3). Each load-bearing plate (2) is connected to the second sensitive platform (6) through a set of second wire-drawing constraint group (4). The second sensitive platform (6) is fixedly connected to the other side of the corresponding load-bearing plate (2) through each second wire-drawing constraint group (4). The first wire drawing constraint group (3) constrains the first sensitive platform (5) in the vertical direction and in the horizontal direction perpendicular to the axial direction of the first sensitive platform (5) for translational and rotational degrees of freedom. The first sensitive platform (5) translates or rotates in the axial direction. The first micro-pusher (7) pushes the first sensitive platform (5) to move in the axial direction. The second wire drawing constraint group (4) constrains the second sensitive platform (6) in the vertical direction and in the horizontal direction perpendicular to the axial direction of the second sensitive platform (6) for translational or rotational degrees of freedom. The second sensitive platform (6) translates and rotates in the axial direction. The second micro-pusher (8) pushes the second sensitive platform (6) to move in the axial direction.

2. The integrated weak force measurement device with strong differential as described in claim 1, characterized in that, It also includes a first feedback control component, which includes a first displacement sensor and a first feedback control actuator. The first displacement sensor is disposed on the first sensitive platform (5), and the first feedback control actuator includes a first conductor and a first magnet. The first magnet is fixed on the load-bearing frame, and the first conductor is disposed on the first sensitive platform (5). It also includes a second feedback control component, which includes a second displacement sensor and a second feedback control actuator. The second displacement sensor is disposed on the second sensitive stage (6), and the second feedback control actuator includes a second conductor and a second magnet. The second magnet is fixed on the support frame, and the second conductor is disposed on the second sensitive stage (6).

3. The integrated weak force measurement device with strong differential as described in claim 2, characterized in that, The first sensitive platform (5) includes a pair of parallel first end face frames (15). Each first end face frame (15) is fixedly connected by multiple first horizontal connecting rods (11) along the axial direction. The multiple first horizontal connecting rods (11) are evenly distributed along the circumferential direction of the first sensitive platform (5). Each first end face frame (15) is connected to the corresponding load-bearing plate (2) through a set of first wire-drawing constraint groups (3). The first sensitive platform (5) also includes a first support plate arranged perpendicular to the axial direction. Both ends of the first support plate are fixedly connected to the first horizontal connecting rods (11) at the same height. A first micro-pusher (7) is fixed on the first support plate. Multiple first fixing holes with the same interval are arranged circumferentially on the first end face frame (15). The first horizontal connecting rods (11) are connected to the first end face frame (15) through the first fixing holes. The second sensitive platform (6) includes a pair of parallel second end face frames (16). Each second end face frame (16) is fixedly connected by multiple second horizontal connecting rods (12) along the axial direction. The multiple second horizontal connecting rods (12) are evenly distributed along the circumferential direction of the second sensitive platform (6). Each second end face frame (16) is connected to the corresponding load-bearing plate (2) through a set of second wire-drawing constraint groups (4). The second sensitive platform (6) also includes a second support plate arranged perpendicular to the axial direction. Both ends of the second support plate are fixedly connected to the second horizontal connecting rods (12) at the same height. A second micro-pusher (8) is fixed on the second support plate. Multiple second fixing holes with the same intervals are arranged circumferentially on the second end face frame (16). The second horizontal connecting rods (12) are connected to the second end face frame (16) through the second fixing holes. The first horizontal connecting rod (11) and the second horizontal connecting rod (12) are staggered.

4. The integrated weak force measurement device with strong differential as described in claim 3, characterized in that, The first wire-drawing constraint group (3) includes a first adjustment component and multiple first fixed wires of the same length. One end of the first fixed wire is fixed on the first sensitive platform (5), and the other end of the first fixed wire is fixed on the load-bearing frame. The fixing points of all the first fixed wires on the first sensitive platform (5) are evenly distributed on the same circumference, and the fixing points of all the first fixed wires on the load-bearing frame are evenly distributed on the same circumference. One of the first fixed wires is vertical. The first adjustment component is symmetrically arranged on both sides of the first sensitive platform (5) with the first fixed wire in the vertical direction. All the first fixed wires are coplanar and perpendicular to the axial direction of the first sensitive platform (5).

5. The integrated weak force measuring device with strong differential as described in claim 4, characterized in that, The first adjustment assembly includes a first adjustment wire, a first fixed pulley, a weight, and a first spring. One end of the first adjustment wire is fixed on the first sensitive platform (5), and the fixing point of the first adjustment wire on the first sensitive platform (5) is symmetrical to the fixing point of the first fixed wire in the vertical direction on the first sensitive platform (5). The first fixed pulley is fixed on the load-bearing frame. The other end of the first adjustment wire passes through the first fixed pulley and is hung with a weight. The first fixed pulley is located directly above the fixing point of the first adjustment wire on the first sensitive platform (5), so that the first adjustment wire is also in the vertical direction. The first adjustment wire and the first fixed wire are coplanar. The second spring is set on the second adjustment wire.

6. The integrated weak force measurement device with strong differential as described in claim 5, characterized in that, The second wire-drawing constraint group (4) includes a second adjustment component and multiple second fixed wires of the same length. One end of the second fixed wire is fixed on the second sensitive platform (6), and the other end of the second fixed wire is fixed on the load-bearing frame. The fixing points of all the second fixed wires on the second sensitive platform (6) are evenly distributed on the same circumference, and the fixing points of all the second fixed wires on the load-bearing frame are evenly distributed on the same circumference. One of the second fixed wires is vertical. The second adjustment component is symmetrically arranged on both sides of the second sensitive platform (6) with the second fixed wire in the vertical direction. All the second fixed wires are coplanar and perpendicular to the axial direction of the second sensitive platform (6).

7. The integrated weak force measurement device with strong differential as described in claim 6, characterized in that, The second adjustment assembly includes a second adjustment wire, a second fixed pulley, a weight, and a second spring. One end of the second adjustment wire is fixed on the second sensitive platform (6), and the fixing point of the second adjustment wire on the second sensitive platform (6) is symmetrical to the fixing point of the vertical second fixed wire on the second sensitive platform (6). The second fixed pulley is fixed on the load-bearing frame. The other end of the second adjustment wire passes through the second fixed pulley and is hung with a weight. The second fixed pulley is located directly above the fixing point of the second adjustment wire on the second sensitive platform (6), so that the second adjustment wire is also vertical. The second adjustment wire and the second fixed wire are coplanar. The second spring is set on the second adjustment wire.

8. A method for measuring weak forces, characterized in that, The integrated weak force measuring device with strong differential as described in any one of claims 1 to 7 includes the following steps: Step 1: Measure the interference force generated by environmental noise using the first sensitive platform (5). ; Step 2: Measure the force to be measured using the second sensitive stage (6). +Interference caused by environmental noise The combined force ; Step 3, the force to be measured Equal to resultant force Subtract interference .

9. The method for measuring weak forces according to claim 8, characterized in that, The interference force generated by environmental noise is measured through the first sensitive platform (5). Specifically: The displacement of the first sensitive platform (5) relative to its initial position in the axial direction under the action of the disturbance force is measured by the first displacement sensor. And based on the measured displacement of the first sensitive platform (5) in the axial direction relative to the initial position, Calculate the velocity of the first sensitive platform (5) and the acceleration of the first sensitive platform (5) The interference force is then calculated using the following formula: ； In the formula, , , All are the first open-loop calibration coefficients. The first mass is the total mass of the first sensitive platform (5), the first micro-thruster (7), and the first support plate. The first damping coefficient, The first elastic coefficient; The force to be measured plus the interference force generated by environmental noise is measured through the second sensitive stage (6). The combined force Specifically: The force to be measured is applied to the second sensitive stage (6) by the second micro-thruster (8), and the displacement of the second sensitive stage (6) in the axial direction relative to the initial position is measured by the second displacement sensor under the combined force of the force to be measured and the interference force. And based on the measured displacement of the second sensitive platform (6) in the axial direction relative to the initial position, Calculate the velocity of the second sensitive platform (6) acceleration of the second sensitive platform (6) The resultant force of the measured force and the interfering force is then calculated using the following formula: ； In the formula, , , All are the second open-loop calibration coefficients. The second mass is the total mass of the second sensitive platform (6), the second micro-thruster (8), and the second support plate. This is the second damping coefficient. This is the second elastic coefficient.

10. The method for measuring weak forces according to claim 8, characterized in that, The interference force generated by environmental noise is measured through the first sensitive platform (5). Specifically: A current is passed through the first conductor. The magnitude of the current in the first conductor is adjusted according to the displacement change of the first sensitive platform (5) in the axial direction relative to the initial position, as measured by the first displacement sensor, so that the displacement measured by the first displacement sensor is 0. The magnetic force applied by the first magnet to the second sensitive platform (6) Interference force exerted by environmental noise on the second sensitive platform (6) If the magnitudes are equal, the interference force generated by environmental noise is calculated using the following formula: ； In the formula, The first closed-loop calibration coefficient, The current flowing through the first conductor; The force to be measured plus the interference force generated by environmental noise is measured through the second sensitive stage (6). The combined force Specifically: The force to be measured is applied to the second sensitive stage (6) by the second micro-thruster (8), and current is passed through the second conductor. The magnitude of the current in the second conductor is adjusted according to the displacement change of the second sensitive stage (6) in the axial direction relative to the initial position measured by the second displacement sensor, so that the displacement measured by the second displacement sensor is 0, and the magnetic force applied by the second magnet to the second sensitive stage (6) is... The magnitude is equal to the force to be measured applied by the second micro-thruster (8). Interference force exerted by environmental noise on the second sensitive platform (6) The combined force If the magnitudes are equal, the resultant force of the force to be measured plus the interfering force is calculated using the following formula: ； In the formula, These are the second closed-loop calibration coefficients. This refers to the current flowing into the second conductor.

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