Strong-difference integrated weak force measuring device and measuring method

Abstract

The invention discloses a strong-difference integrated weak force measuring device which comprises a first sensitive table body, a leveling base, a bearing frame, a second sensitive table body, a first displacement sensor, a first feedback control actuator, a second displacement sensor and a second feedback control actuator, and further discloses a weak force measuring method. According to the invention, two sets of nested identical weak force test sensitive table bodies are constructed, the first sensitive table body is used for detecting environmental noise such as structural deformation, residual airflow disturbance and ground micro-vibration, the second sensitive table body is used for detecting micro-thrust to be tested and measuring the first environmental noise, and the measurement value of the second sensitive table body is deducted from common-mode environmental noise, so that the micro-thrust to be tested can be tested. Therefore, a high-precision thrust signal to be measured is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision inertial device testing, and particularly relates to an integrated weak force measurement device with strong differential, and also relates to a weak force measurement method. Background Art

[0002] Nowadays, aerospace technology has developed rapidly, and various satellites have been successively launched into orbit to undertake different detection tasks. Spaceborne microthrusters are the basis for microsatellites to achieve precise attitude control, orbit control, and rapid maneuvering. With the accelerated development of low-earth orbit satellite networking and deep space exploration beyond the earth, the demand for high-performance thrusters has increased significantly. To ensure their working performance in the space environment, it is necessary to conduct detailed tests on the performance indicators of the above-mentioned microthrusters on the ground.

[0003] On the ground, not only the test interferences brought by the thruster itself, such as the working medium pressure fluctuation and valve movement of the thruster, but also the influence from environmental fluctuations between the thruster and the thrust test bench need to be considered, such as the earth tilt solid tide effect, surface microvibration, environmental temperature, electromagnetic field fluctuation, etc., making the high-precision test and calibration of thrust very difficult.

[0004] To meet the needs of micro-thrust testing, scholars at home and abroad have studied various configurations of thrust test benches, such as torsion pendulum type, balance type, and suspension pendulum type. Internationally, typical high-precision test benches, such as the classic torsion pendulum suspended by a wire designed by NASA in 2002 for the ground test of microthrusters in the LISA project; the torsion pendulum test bench rotating in the horizontal plane developed by Photonic Associates in the United States in 2005, achieving a test resolution of 0.03 μN under a measurement bandwidth of 0.1 Hz; domestically, the special suspension vertical axis torsion pendulum developed by Huazhong University of Science and Technology in 2012 was used to test the pulsed plasma thruster, achieving a thrust measurement resolution of 0.09 μN; in 2018, the Institute of Mechanics, Chinese Academy of Sciences and Beihang University in 2021 developed micro-thrust test benches based on the principle of vertical axis horizontal torsion pendulum respectively, with a measurement range of about 200 - 400 μN and a resolution reaching 0.1 μN; in 2020, the test bench built by Sun Yat-sen University and the Institute of Precision Measurement Science and Technology, Chinese Academy of Sciences using weak force sensitive configurations such as balanced vertical torsion pendulum achieved a measurement level with the actual thruster test noise significantly better than 0.1 μN for kilograms. Among the above test benches, some adopt structural designs and technical means that can suppress noise in common mode based on their own principles, but usually limited by the low similarity and consistency of the sensitive structures, it is difficult to break through the suppression of environmental common mode noise to more than 20 dB.

[0005] In the measurement of weak forces with higher precision, the common-mode noise suppression ability still needs to be further improved. Especially in the low-frequency and higher-frequency bands, the test noise is close to or even far exceeds the test requirements. There is an urgent need for new technical means to achieve a breakthrough. Summary of the Invention

[0006] The object of the present invention is to provide an integrated weak force measurement device with strong differential, and also provide a weak force measurement method, aiming at the above problems existing in the prior art.

[0007] The above object of the present invention is achieved by the following technical means:

[0008] An integrated weak force measurement device with strong differential includes a first sensitive platform, and also includes a leveling base, a load-bearing frame, and a second sensitive platform. The load-bearing frame is arranged on the leveling base. The first sensitive platform is connected to the load-bearing frame through multiple sets of first wire restraint groups. The second sensitive platform is connected to the load-bearing frame through multiple sets of second wire restraint groups. The first sensitive platform and the second sensitive platform are nested. A first micro thruster is arranged on the first sensitive platform, and a second micro thruster is arranged on the second sensitive platform. The load-bearing frame includes a pair of load-bearing plates, and both load-bearing plates are arranged 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 restraint groups. Each load-bearing plate is connected to the first sensitive platform through a set of first wire restraint groups. The first sensitive platform is fixedly connected to the same side surface of the corresponding load-bearing plate through each first wire restraint group. Each load-bearing plate is connected to the second sensitive platform through a set of second wire restraint groups. The second sensitive platform is fixedly connected to the other same side surface of the corresponding load-bearing plate through each second wire restraint group.

[0009] It also includes a first feedback control component. The first feedback control component includes a first displacement sensor and a first feedback control actuator. The first displacement sensor is arranged on the first sensitive platform. The first feedback control actuator includes a first conductor part and a first magnet part. The first magnet part is fixed on the load-bearing frame, and the first conductor part is arranged on the first sensitive platform;

[0010] It also includes a second feedback control component. The second feedback control component includes a second displacement sensor and a second feedback control actuator. The second displacement sensor is arranged on the second sensitive platform. The second feedback control actuator includes a second conductor part and a second magnet part. The second magnet part is fixed on the load-bearing frame, and the second conductor part is arranged on the second sensitive platform.

[0011] As described above, the first sensitive table body includes a pair of parallel first end frames. Each first end frame is fixedly connected by a plurality of first horizontal connecting rods along the axial direction. The plurality of first horizontal connecting rods are evenly distributed along the circumferential direction of the first sensitive table body. Each first end frame is connected to the corresponding load-bearing plate through a set of first wire drawing restraint groups; the first sensitive table body further 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-thruster is fixed on the first support plate. A plurality of equally spaced first fixing holes are circumferentially arranged on the first end frame. The first horizontal connecting rods are connected to the first end frame through the first fixing holes;

[0012] The second sensitive table body includes a pair of parallel second end frames. Each second end frame is fixedly connected by a plurality of second horizontal connecting rods along the axial direction. The plurality of second horizontal connecting rods are evenly distributed along the circumferential direction of the second sensitive table body. Each second end frame is connected to the corresponding load-bearing plate through a set of second wire drawing restraint groups; the second sensitive table body further 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-thruster is fixed on the second support plate. A plurality of equally spaced second fixing holes are circumferentially arranged on the second end frame. The second horizontal connecting rods are connected to the second end frame through the second fixing holes;

[0013] The first horizontal connecting rods and the second horizontal connecting rods are arranged staggeredly.

[0014] As described above, the first wire drawing restraint group includes a first adjusting component and a plurality of first fixing wires of the same length. One end of each first fixing wire is fixed on the first sensitive table body, and the other end of each first fixing wire is fixed on the load-bearing frame. The fixing points of all the first fixing wires on the first sensitive table body are evenly distributed on the same circumference. The fixing points of all the first fixing wires on the load-bearing frame are evenly distributed on the same circumference;

[0015] One of the first fixing wires is in the vertical direction. The first adjusting component is symmetrically arranged on both sides of the first sensitive table body with respect to the first fixing wire in the vertical direction. All the first fixing wires are coplanar and perpendicular to the axial direction of the first sensitive table body.

[0016] As described above, the first adjustment component includes a first adjustment wire, a first fixed pulley, weights, and a first spring. One end of the first adjustment wire is fixed to the first sensitive body, and the fixing point of the first adjustment wire on the first sensitive body is symmetrical to the fixing point of the first fixed wire in the vertical direction on the first sensitive body. The first fixed pulley is fixed to the load-bearing frame. The other end of the first adjustment wire passes through the first fixed pulley and is hung with weights. The first fixed pulley is located directly above the fixing point of the first adjustment wire on the first sensitive body, such 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 arranged on the second adjustment wire.

[0017] As described above, the second wire constraint group 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 body, and the other end of each second fixed wire is fixed to the load-bearing frame. The fixing points of all the second fixed wires on the second sensitive body 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;

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

[0019] As described above, the second adjustment component includes a second adjustment wire, a second fixed pulley, weights, and a second spring. One end of the second adjustment wire is fixed to the second sensitive body, and the fixing point of the second adjustment wire on the second sensitive body is symmetrical to the fixing point of the second fixed wire in the vertical direction on the second sensitive body. The second fixed pulley is fixed to the load-bearing frame. The other end of the second adjustment wire passes through the second fixed pulley and is hung with weights. The second fixed pulley is located directly above the fixing point of the second adjustment wire on the second sensitive body, such that the second adjustment wire is also in the vertical direction; the second adjustment wire and the second fixed wire are coplanar; the second spring is arranged on the second adjustment wire.

[0020] A method for measuring weak force, using a highly differential integrated weak force measuring device as described above, includes the following steps:

[0021] Step 1: Measure the interference force F generated by environmental noise through the first sensitive body 干扰 ;

[0022] Step 2: Measure the resultant force F of the force to be measured F 待测 + the interference force F generated by environmental noise 干扰 through the second sensitive body 合力 ;

[0023] Step 3: The force to be measured F 待测 is equal to the resultant force F合力 Subtract the interference force F 干扰 .

[0024] As described above, measure the interference force F generated by environmental noise through the first sensitive body 干扰 Specifically:

[0025] Measure the displacement x1 of the first sensitive body in the axial direction relative to the initial position under the action of the interference force through the first displacement sensor, and calculate the velocity of the first sensitive body according to the measured displacement x1 of the first sensitive body in the axial direction relative to the initial position and the acceleration of the first sensitive body Then calculate the interference force through the following formula:

[0026]

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

[0028] Measure the resultant force F of the interference force F generated by the force to be measured + environmental noise through the second sensitive body 干扰 of 合力 Specifically:

[0029] Apply the force to be measured to the second sensitive body through the second micro thruster, measure the displacement x2 of the second sensitive body in the axial direction relative to the initial position under the action of the resultant force of the force to be measured + interference force through the second displacement sensor, and calculate the velocity of the second sensitive body according to the measured displacement x2 of the second sensitive body in the axial direction relative to the initial position and the acceleration of the second sensitive body Then calculate the resultant force of the force to be measured + interference force through the following formula:

[0030]

[0031] In the formula, M2, C2, and K2 are all the 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, measure the interference force F generated by environmental noise through the first sensitive body 干扰 Specifically:

[0033] Pass a current through the first conductor, adjust the magnitude of the current in the first conductor according to the displacement change of the first sensitive body measured by the first displacement sensor in the axial direction relative to the initial position, so that the displacement measured by the first displacement sensor is 0, and the magnetic force F3 exerted by the first magnet on the second sensitive body is equal to the interference force F exerted by the environmental noise on the second sensitive body干扰 If they are equal in magnitude, the disturbing force generated by environmental noise is calculated by the following formula:

[0034] F 干扰 = F3 = -k c1 I1

[0035] where k c1 is the first closed-loop calibration coefficient, and I1 is the current applied to the first conductor;

[0036] The resultant force F 干扰 of the measured force + the disturbing force F generated by environmental noise measured by the second sensitive platform 合力 is specifically:

[0037] Apply the measured force to the second sensitive platform through the second micro-thruster, apply current to the second conductor, and adjust the magnitude of the current in the second conductor according to the displacement change of the second sensitive platform relative to the initial position in the axial direction measured by the second displacement sensor, so that the displacement measured by the second displacement sensor is 0, and the magnitude of the magnetic force F4 applied by the second magnet to the second sensitive platform is equal to the measured force F 待测 applied by the second micro-thruster and the disturbing force F 干扰 applied by environmental noise to the second sensitive platform 合力 If they are equal in magnitude, the resultant force of the measured force + the disturbing force is calculated by the following formula:

[0038] F 合力 = F4 = -k c2 I2

[0039] where k c2 is the second closed-loop calibration coefficient, and I2 is the current applied to the second conductor.

[0040] The present invention has the following beneficial effects compared with the prior art:

[0041] The present invention constructs two sets of nested sensitive platforms with the same design for measuring weak forces. The first sensitive platform is used to detect environmental noises such as structural deformation, residual airflow disturbance, and ground micro-vibration. The second sensitive platform measures the environmental noise while detecting the measured micro-thrust. By subtracting the common-mode environmental noise from the measurement value of the second sensitive platform, a high-precision measured thrust signal can be obtained. Description of the Drawings

[0042] Figure 1 is a schematic structural diagram of the load-bearing frame, the first sensitive platform, and the second sensitive platform of the present invention connected;

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

[0044] Figure 3 Structural schematic diagram of one of the sensitive platforms (the first sensitive platform or the second sensitive platform) of the present invention;

[0045] Figure 4 Schematic diagram of the open-loop measurement of the present invention;

[0046] Figure 5 Schematic diagram of the closed-loop measurement of the present invention;

[0047] Figure 6 Schematic diagram of the connection between one of the sensitive platforms of the present invention and the corresponding calibration ball and the moving displacement stage;

[0048] Reference numerals and corresponding component names:

[0049] 1 - leveling base; 2 - load-bearing plate; 3 - first wire drawing restraint group; 4 - second wire drawing restraint group; 5 - first sensitive platform; 6 - second sensitive platform 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 - moving displacement stage; 15 - first end face frame; 16 - second end face frame. Detailed implementation manners

[0050] To facilitate the understanding and implementation of the present invention by those of ordinary skill in the art, the present invention will be further described in detail below with reference to embodiments. The embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0051] Embodiment 1:

[0052] A strongly differential integrated weak force measurement device includes a leveling base 1, a load-bearing frame, a columnar first sensitive platform 5, a columnar second sensitive platform 6, a first micro thruster 7, a first feedback control component, a second micro thruster 8, and a second feedback control component. The load-bearing frame is arranged on the leveling base 1. The first sensitive platform 5 is connected to the load-bearing frame through multiple sets of first wire drawing restraint groups 3. The first micro thruster 7 is arranged on the first sensitive platform 5. The first wire drawing restraint groups 3 restrict the translational and rotational degrees of freedom of the first sensitive platform 5 in the vertical direction and the horizontal direction perpendicular to the axial direction of the first sensitive platform 5. The first sensitive platform 5 can translate or rotate in the axial direction, and the first micro thruster 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 restraint groups 4. The second micro thruster 8 is arranged on the second sensitive platform 6. The second wire drawing restraint groups 4 restrict 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 thruster 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, and the load-bearing plates 2 are both arranged on the leveling base 1. The load-bearing plates 2 have the same set thickness, and the number of the load-bearing plates 2 is the same as that of the first wire drawing restraint groups 3. Each load-bearing plate 2 is connected to the first sensitive body 5 through a set of first wire drawing restraint groups 3. The first sensitive body 5 is fixedly connected to the same side surface of the corresponding load-bearing plate 2 through each set of first wire drawing restraint groups 3 respectively. Each load-bearing plate 2 is connected to the second sensitive body 6 through a set of second wire drawing restraint groups 4. The second sensitive body 6 is fixedly connected to the other same side surface of the corresponding load-bearing plate 2 through each set of second wire drawing restraint groups 4 respectively. Therefore, the first sensitive body 5 and the second sensitive body 6 are nested and staggered, and do not affect each other's movement in the axial direction, so that there is a millimeter-level spacing of the set thickness of the load-bearing plate 2 between the first sensitive body 5 and the second sensitive body 6, and further do not affect each other's movement in the axial direction.

[0054] It further includes a first feedback control component. The first feedback control component includes a first displacement sensor and a first feedback control actuator. The first displacement sensor is arranged on the first sensitive body 5. The first feedback control actuator includes a first conductor part and a first magnet part. The first magnet part is fixed on the load-bearing frame, and the first conductor part is arranged on the first sensitive body 5;

[0055] The electric signal applied in the first conductor will generate a feedback force in the magnetic field generated by the first magnet part, which is used for negative feedback on the displacement of the first sensitive body 5, so that the first sensitive body 5 is stabilized at the initial position, and at this time the displacement measured by the displacement sensor is 0;

[0056] It further includes a second feedback control component. The second feedback control component includes a second displacement sensor and a second feedback control actuator. The second displacement sensor is arranged on the second sensitive body 6. The second feedback control actuator includes a second conductor part and a second magnet part. The second magnet part is fixed on the load-bearing frame, and the second conductor part is arranged on the second sensitive body 6; The second position sensor measures the displacement change of the second sensitive body 6 and converts the displacement change into an electric signal and conducts it into the second conductor part. The electric signal applied in the second conductor will generate a feedback force in the magnetic field generated by the second magnet part, which is used for negative feedback on the displacement of the second sensitive body 6, so that the second sensitive body 6 is stabilized at the initial position, and at this time the displacement measured by the displacement sensor is 0.

[0057] As an implementable mode, a first fixing rod is provided on the first sensitive table body 5 along the axial direction. The first magnet member is a permanent magnet, denoted as the first permanent magnet, and the conductor member is a coil, denoted as the first coil. The first permanent magnet is fixed on the bearing frame, and the first coil is wound and fixed on the first fixing rod. When the first sensitive table body 5 moves along the axial direction, the first permanent magnet drives the first coil to move in the opposite direction, so that the first sensitive table body 5 is stabilized at the initial position; a second fixing rod is provided on the second sensitive table body 6 along the axial direction. The second magnet member is a permanent magnet, denoted as the second permanent magnet, and the conductor member is a coil, denoted as the second coil. The second permanent magnet is fixed on the bearing frame, and the second coil is wound and fixed on the second fixing rod. When the second sensitive table body 6 moves along the axial direction, the second permanent magnet drives the second coil to move in the opposite direction, so that the second sensitive table body 6 is stabilized at the initial position.

[0058] The first wire drawing restraint group 3 includes a first adjusting assembly and a plurality of first fixing wires of the same length. One end of each first fixing wire is fixed on the first sensitive table body 5, and the other end of each first fixing wire is fixed on the bearing frame. The fixing points of all the first fixing wires on the first sensitive table body 5 are evenly distributed on the same circumference, and the fixing points of all the first fixing wires on the bearing frame are evenly distributed on the same circumference;

[0059] One of the first fixing wires is in the vertical direction, and the first adjusting assembly is symmetrically arranged on both sides of the first sensitive table body 5 with respect to the first fixing wire in the vertical direction;

[0060] All the first fixing wires are coplanar and perpendicular to the axial direction of the first sensitive table body 5;

[0061] The first adjusting assembly includes a first adjusting wire, a first fixed pulley, and a first spring. One end of the first adjusting wire is fixed on the first sensitive table body 5, and the fixing point of the first adjusting wire on the first sensitive table body 5 is symmetric with the fixing point of the first fixing wire in the vertical direction on the first sensitive table body 5 (symmetric about the vertical central axis of the cross-section of the first sensitive table body 5). The first fixed pulley is fixed on the bearing frame. The other end of the first adjusting wire passes through the first fixed pulley and hangs a weight of appropriate weight. The first fixed pulley is located directly above the fixing point of the first adjusting wire on the first sensitive table body 5, so that the first adjusting wire is also in the vertical direction; wherein, the weight can also be replaced by other heavy objects of appropriate weight, and the first adjusting wire and the first fixing wire are coplanar;

[0062] The first adjusting assembly further includes a first spring, and the first spring is arranged on the first adjusting wire.

[0063] The second sensitive table body 6 is also connected to the bearing frame through the second wire drawing restraint group 4 in the same way, specifically:

[0064] The second wire drawing restraint group 4 includes a second adjusting component and multiple second fixed wire drawings of the same length. One end of each second fixed wire drawing is fixed on the second sensitive body 6, and the other end is fixed on the load-bearing frame. The fixing points of all the second fixed wire drawings on the second sensitive body 6 are evenly distributed on the same circumference, and the fixing points of all the second fixed wire drawings on the load-bearing frame are evenly distributed on the same circumference. One of the second fixed wire drawings is in the vertical direction, and the second adjusting component is symmetrically arranged on both sides of the second sensitive body 6 with respect to the second fixed wire drawing in the vertical direction.

[0065] All the second fixed wire drawings are coplanar and perpendicular to the axial direction of the second sensitive body 6.

[0066] The second adjusting component includes a second adjusting wire drawing, a second fixed pulley, and a second spring. One end of the second adjusting wire drawing is fixed on the second sensitive body 6, and the fixing point of the second adjusting wire drawing on the second sensitive body 6 is symmetric with the fixing point of the second fixed wire drawing in the vertical direction (symmetric about the vertical central axis of the cross-section of the second sensitive body 6). The second fixed pulley is fixed on the load-bearing frame. The other end of the second adjusting wire drawing passes through the second fixed pulley and hangs a weight of appropriate mass. The second fixed pulley is directly above the fixing point of the second adjusting wire drawing on the second sensitive body 6, so that the second adjusting wire drawing is also in the vertical direction. Among them, the weight can also be replaced by other heavy objects of appropriate mass, and the second adjusting wire drawing and the second fixed wire drawing are coplanar.

[0067] The second adjusting component further includes a second spring, and the second spring is arranged on the second adjusting wire drawing.

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

[0069] The first sensitive body 5 and the second sensitive body 6 of the present invention are respectively constrained in degrees of freedom by a total of eight equal-length wire draws that are divided into two groups and located on two planes. The degrees of freedom of translational motion of the first sensitive body 5 and the second sensitive body 6 along the axial direction are the flexible degrees of freedom required for micro-thrust testing. When the wire draws all maintain tension, the translational motion of the body along the horizontal axial direction is a flexible degree of freedom. When a micro-thrust acts in the axial direction of the first sensitive body 5 and the second sensitive body 6, the connection points of the two groups of wire draws on one side of the body leave the original plane. Since six of the wire draws (i.e., the first fixed wire draws and the second fixed wire draws) are inextensible, the body will undergo a slight rotation. The other two wire draws (i.e., the first adjustment wire draws and the second adjustment wire draws) will maintain the tension (approximate) of the entire elastic structure unchanged through the elongation 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 body are directly constrained by the tension of the wire draws. Thus, the present invention constructs a sensitive direction suitable for micro-thrust testing in the axial direction.

[0070] Each first end face frame 15 of the first sensitive body 5 is fixedly connected through a plurality of first horizontal connecting rods 11 arranged along the axial direction. The plurality of first horizontal connecting rods 11 are evenly distributed along the circumferential direction of the first sensitive body 5. Each first end face frame 15 is connected to the corresponding load-bearing plate 2 through a set of first wire draw constraint groups 3. The first sensitive body 5 further 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-thruster 7 is fixed on the first support plate. A plurality of equally spaced first fixing holes are circumferentially arranged 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 structure of the second sensitive body 6 is the same as that of the first sensitive body 5. Specifically, each second end face frame 16 of the second sensitive body 6 is fixedly connected through a plurality of second horizontal connecting rods 12 arranged along the axial direction. The plurality of second horizontal connecting rods 12 are evenly distributed along the circumferential direction of the second sensitive body 6. Each second end face frame 16 is connected to the corresponding load-bearing plate 2 through a set of second wire draw constraint groups 4. The second sensitive body 6 further 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-thruster 8 is fixed on the second support plate. A plurality of equally spaced second fixing holes are circumferentially arranged 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] Among them, the end face frame (the first end face frame 15 or the second end face frame 16) can be circular or other regular shapes (such as regular polygons). The number of horizontal connecting rods (the first horizontal connecting rod 11 or the second horizontal connecting rod 12) can also be increased through the fixing holes (the first fixing hole or the second fixing hole), so as to change the height of the support plate erection, and further change the height of the microthruster, so as to adapt to the installation of microthrusters or microthruster clusters with different masses and volumes;

[0073] The first horizontal connecting rod 11 and the second horizontal connecting rod 12 are arranged staggeredly, and the first microthruster 7 and the second microthruster 8 are arranged staggeredly, so that the movements of the first sensitive platform body 5 and the second sensitive platform body 6 in the axial direction do not affect each other.

[0074] A controller 9 is also arranged on the leveling base 1, including a first controller and a second controller. The first controller is connected to the first microthruster 7 and the first conductor through a signal cable 10, and the second controller is connected to the second microthruster 8 and the second conductor through a signal cable 10.

[0075] Among them, the first sensitive platform body 5 and the first microthruster 7 constructed by the present invention are used to detect the total force of structural deformation, residual airflow disturbance, ground microvibration, or other environmental noises. Based on the above structure, in the same support structure and the same working space, two sets of sensitive platform bodies with the same design are constructed in a nested manner. The first set is used to detect environmental noises such as structural deformation, residual airflow disturbance, and ground microvibration, and the second set measures the environmental noises of the first set while measuring the microthrust to be measured. The system processes the data in real time and deducts the common-mode environmental noises, so as to obtain a high-precision thrust signal to be measured. The measured value F test and the expected thrust F expect are compared, and the measurement accuracy is evaluated in combination with the measurement noise and repeatability.

[0076] Embodiment 2:

[0077] A weak force measurement method uses the integrated weak force measurement device with strong differential described in Embodiment 1, and includes the following steps:

[0078] Step 1: Measure the interference force F generated by environmental noise through the first sensitive platform body 5 干扰 ;

[0079] Step 2: Measure the resultant force F of the force to be measured + the interference force F generated by environmental noise through the second sensitive platform body 6 干扰 ; 合力 ;

[0080] Step 3: The force to be measured F 待测 is equal to the resultant force F 合力 minus the interference force F 干扰 .

[0081] In this embodiment, the force to be measured generated by the second micro-thruster 8 is measured by open-loop, specifically:

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

[0083] The displacement of the first sensitive platform 5 in the axial direction relative to the initial position under the action of the interference force is measured by the first displacement sensor, and the velocity and acceleration of the first sensitive platform 5 are calculated according to the measured displacement of the first sensitive platform 5 in the axial direction relative to the initial position. Then, the interference force is calculated through the following formula:

[0084]

[0085] In the formula, x1 is the displacement of the first sensitive platform 5 in the axial direction relative to the initial position under the action of the interference force, is the velocity of the first sensitive platform 5, is the acceleration of the first sensitive platform 5. M1, 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 + the interference force generated by environmental noise is measured by the second sensitive platform 6, specifically:

[0087] The force to be measured is applied to the second sensitive platform 6 by the second micro-thruster 8. The displacement of the second sensitive platform 6 in the axial direction relative to the initial position under the action of the resultant force of the force to be measured + the interference force is measured by the second displacement sensor, and the velocity and acceleration of the second sensitive platform 6 are calculated according to the measured displacement of the second sensitive platform 6 in the axial direction relative to the initial position. Then, the resultant force of the force to be measured + the interference force is calculated through the following formula:

[0088]

[0089] In the formula, x2 is the displacement of the second sensitive platform 6 in the axial direction relative to the initial position under the action of the interference force, is the velocity of the second sensitive platform 6, is the acceleration of the second sensitive platform 6. M2, C2, and K2 are all 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 is equal to the resultant force F 合力 minus 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 calibration ball 13 and the one-dimensional moving displacement stage 14.

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

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

[0094] By moving the first moving displacement stage, a component force is generated in the axial direction of the first sensitive platform 5 by the first wire, so as to apply a first standard weak force F1 to the first sensitive platform 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 acceleration due to gravity, x3 is the distance moved by the first moving displacement stage, and L1 is the length of the first wire.

[0097] Then, the displacement of the first sensitive platform 5 in the axial direction relative to the initial position under the action of the interference force is measured by the first displacement sensor, and the velocity and acceleration of the first sensitive platform 5 are calculated according to the measured displacement of the first sensitive platform 5 in the axial direction relative to the initial position. Then, the first open-loop calibration coefficients M1, C1, and K1 are obtained by fitting with the following formula:

[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 manner:

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

[0102] By moving the second moving displacement stage, a component force is generated in the axial direction of the second sensitive platform 6 by the second wire, so as to apply a second standard weak force F1 to the second sensitive platform 6. The second standard weak force F1 is:

[0103]

[0104] Where m2 is the mass of the second calibration ball, x4 is the distance moved by the second motion stage, and L2 is the length of the second pull wire;

[0105] The second displacement sensor is then used to measure the displacement of the second sensitive platform 6 in the axial direction relative to the initial position under the action of the interference force, and the velocity and acceleration of the second sensitive platform 6 are calculated according to the measured displacement of the second sensitive platform 6 in the axial direction relative to the initial position, and the second open-loop calibration coefficients M2, C2, and K2 are obtained by fitting through the following formula:

[0106]

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

[0108] Embodiment 3:

[0109] A weak force measurement method, using a strong differential integrated weak force measurement device described in Example 1, this embodiment measures the force to be measured generated by the second micro-thruster 8 through a closed loop, specifically:

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

[0111] Current is passed through the first conductor, and 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 measured by the first displacement sensor, so that the displacement measured by the first displacement sensor is 0, and the first sensitive platform 5 is stable at the initial position, indicating that the magnetic force F3 exerted by the first magnetic part on the second sensitive platform 6 and the interference force F exerted by the environmental noise on the second sensitive platform 6 are equal. 干扰 If the magnitudes are equal, the interference force generated by the environmental noise is calculated by the following formula:

[0112] F 干扰 =F3=-k c1 I1

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

[0114] The combined force of the force to be measured and the interference force generated by the environmental noise is measured by the second sensitive platform 6, specifically:

[0115] Apply the force to be measured to the second sensitive body 6 through the second micro-thruster 8, pass a current through the second conductor, and adjust the magnitude of the current in the second conductor according to the displacement change of the second sensitive body 6 relative to the initial position in the axial direction measured by the second displacement sensor, so that the displacement measured by the second displacement sensor is 0, and the second sensitive body 6 is stabilized at the initial position, indicating that the magnitude of the magnetic force F4 exerted by the second magnet on the second sensitive body 6 is equal to the force F to be measured applied by the second micro-thruster 8 待测 and the interference force F exerted by the environmental noise on the second sensitive body 6 干扰 resulting in a resultant force F 合力 with equal magnitudes. The resultant force of the force to be measured + interference force is calculated by the following formula:

[0116] F 合力 = F4 = -k c2 I2

[0117] where k c2 is the second closed-loop calibration coefficient, and I2 is the current passed through the second conductor

[0118] Finally, the force to be measured F 待测 is equal to the resultant force F 合力 minus the interference force F 干扰 .

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

[0120] By moving the first moving displacement stage, a component force is generated in the axial direction of the first wire on the first sensitive body 5, thereby applying a first standard weak force F1 to the first sensitive body 5

[0121] Then, pass a current through the first conductor, and adjust the magnitude of the current in the first conductor according to the displacement change of the first sensitive body 5 relative to the initial position in the axial direction measured by the first displacement sensor, so that the displacement measured by the first displacement sensor is 0, and the first sensitive body 5 is stabilized at the initial position, indicating that the magnetic force F3 exerted by the first magnet on the second sensitive body 6 is equal to the first standard weak force F1 in magnitude. Then, the first closed-loop calibration coefficient k can be obtained by fitting through the following formula c1 :

[0122] F1 = F3 = -k c1 I1

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

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

[0125] By moving the second moving displacement stage, a component force is generated in the axial direction of the second pulling wire on the second sensitive body 6, so as to apply a second standard weak force F2 to the second sensitive body 6;

[0126] Then, a current is passed through the second conductor component. According to the displacement change of the second sensitive body 6 relative to the initial position in the axial direction measured by the second displacement sensor, the magnitude of the current in the second conductor component is adjusted so that the displacement measured by the second displacement sensor is 0, and the second sensitive body 6 is stabilized at the initial position, indicating that the magnetic force F3 exerted by the second magnet component on the second sensitive body 6 is equal in magnitude to the second standard weak force F2. Then, the second closed-loop calibration coefficient k can be obtained by fitting with the following formula c1 :

[0127] F2 = F4 = -k c2 I2

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

[0129] It should be noted that the embodiments described in the present invention are only illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A strong differential integrated weak force measurement device, comprising a first sensitive platform (5), characterized in that: The invention also comprises a leveling base (1), a load-bearing frame, and a second sensitive platform (6), wherein the load-bearing frame is arranged on the leveling base (1), the first sensitive platform (5) is connected to the load-bearing frame via a plurality of first wire drawing constraint groups (3), the second sensitive platform (6) is connected to the load-bearing frame via a plurality of second wire drawing constraint groups (4), the first sensitive platform (5) and the second sensitive platform (6) are nested, the first micro-propeller (7) is arranged on the first sensitive platform (5), the second micro-propeller (8) is arranged on the second sensitive platform (6), the load-bearing frame comprises a pair of load-bearing plates (2), and the load-bearing plates (2) are both arranged on the leveling base (1). ), the load-bearing plates (2) all have the same set thickness, the number of the 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 the first sensitive platform (5) through 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) 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 groups (4), the second sensitive platform (6) is fixedly connected to the other same side of the corresponding load-bearing plate (2) through each second wire-drawing constraint group (4).

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

3. The integrated weak force measuring device with strong differential according to claim 2, characterized in that: The first sensitive platform (5) comprises a pair of parallel first end face frames (15), each of which is fixedly connected by a plurality of first horizontal connecting rods (11) along the axial direction, the plurality of first horizontal connecting rods (11) are evenly distributed along the circumferential direction of the first sensitive platform (5), and each first end face frame (15) is connected to a load-bearing plate (2) at a corresponding position through a set of first wire drawing constraint groups (3); the first sensitive platform (5) further comprises a first support plate arranged along a direction perpendicular to the axial direction, the two ends of the first support plate are respectively fixedly connected to the first horizontal connecting rods (11) at the same height, the first micro-thruster (7) is fixed on the first support plate, a plurality of first fixing holes with the same spacing are circumferentially arranged on the first end face frame (15), and the first horizontal connecting rod (11) is connected to the first end face frame (15) through the first fixing holes; The second sensitive platform (6) comprises a pair of parallel second end face frames (16), each of which is fixedly connected via a plurality of second horizontal connecting rods (12) along the axial direction, the plurality of second horizontal connecting rods (12) being evenly distributed along the circumferential direction of the second sensitive platform (6), and each second end face frame (16) being connected to a load-bearing plate (2) at a corresponding position via a set of second wire drawing constraint groups (4); the second sensitive platform (6) further comprises a second support plate arranged along a direction perpendicular to the axial direction, the two ends of the second support plate being respectively fixedly connected to the second horizontal connecting rods (12) at the same height, the second micro-thruster (8) being fixed on the second support plate, a plurality of second fixing holes at the same intervals being circumferentially arranged on the second end face frame (16), and the second horizontal connecting rods (12) being connected to the second end face frame (16) via the second fixing holes; The first horizontal connecting rod (11) and the second horizontal connecting rod (12) are arranged in a staggered manner.

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

5. A strong differential integrated weak force measurement device according to claim 4, characterized in that: The first adjustment component comprises 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 with the fixing point of the first fixed wire on the first sensitive platform (5) in the vertical direction. 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 is coplanar with the first fixed wire. The second spring is arranged on the second adjustment wire.

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

7. The strong differential integrated weak force measurement device according to claim 6, characterized in that: The second adjustment component comprises 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 with the fixing point of the second fixed wire on the second sensitive platform (6) in the vertical direction. 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 in the vertical direction. The second adjustment wire is coplanar with the second fixed wire. The second spring is arranged on the second adjustment wire.

8. A weak force measurement method, characterized in that: An integrated weak force measurement device using any one of claims 1 to 7 with strong differential comprises the following steps: Step 1: Measure the interference force F generated by the environmental noise through the first sensitive platform (5) 干扰 ; Step 2: Measure the force F to be measured by the second sensitive platform (6) 待测 + Interference force caused by environmental noise F 干扰 The resultant force F 合力 ; Step 3: Force to be measured F 待测 Equal to the resultant force F 合力 Subtract the disturbance force F 干扰 .

9. A weak force measurement method according to claim 8, characterized in that: The interference force F generated by the environmental noise is measured by the first sensitive platform (5) 干扰 Specifically: The first displacement sensor measures the displacement x1 of the first sensitive platform (5) in the axial direction relative to the initial position under the action of the interference force, and calculates the speed of the first sensitive platform (5) based on the measured displacement x1 of the first sensitive platform (5) in the axial direction relative to the initial position. and the acceleration of the first sensitive platform (5) The interference force is then calculated using the following formula: Where, M1, C1, and K1 are the first open-loop calibration coefficients, M1 is the first mass, C1 is the first damping coefficient, and K1 is the first elastic coefficient; The second sensitive platform (6) measures the interference force F generated by the force to be measured and the environmental noise. 干扰 The resultant force F 合力 Specifically: A force to be measured is applied to the second sensitive platform (6) by a second micro-propeller (8), a displacement x2 of the second sensitive platform (6) in the axial direction relative to an initial position under the combined force of the force to be measured and the interference force is measured by a second displacement sensor, and a speed of the second sensitive platform (6) is calculated based on the measured displacement x2 of the second sensitive platform (6) in the axial direction relative to the initial position. and the acceleration of the second sensitive platform (6) Then the resultant force of the force to be measured + the interference force is calculated by the following formula: Wherein, M2, C2, and K2 are the second open-loop calibration coefficients, M2 is the second mass, C2 is the second damping coefficient, and K2 is the second elastic coefficient.

10. A weak force measurement method according to claim 8, characterized in that: The interference force F generated by the environmental noise is measured by the first sensitive platform (5) 干扰 Specifically: A current is passed through the first conductor, and 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 measured by the first displacement sensor, so that the displacement measured by the first displacement sensor is 0, and the magnetic force F3 applied by the first magnetic member to the second sensitive platform (6) and the interference force F applied by the environmental noise to the second sensitive platform (6) are equal. 干扰 If the magnitudes are equal, the interference force generated by the environmental noise is calculated by the following formula: F 干扰 =F3=-k c1 I1 In the formula, k c1 is the first closed-loop calibration coefficient, I1 is the current flowing into the first conductor; The second sensitive platform (6) measures the interference force F generated by the force to be measured and the environmental noise. 干扰 The resultant force F 合力 Specifically: A force to be measured is applied to the second sensitive platform (6) by a second micro-propeller (8), and a current is passed through the second conductor. The magnitude of the current in the second conductor is adjusted according to a displacement change of the second sensitive platform (6) in the axial direction relative to an initial position measured by a second displacement sensor, so that the displacement measured by the second displacement sensor is 0, and the magnitude of the magnetic force F4 applied by the second magnetic member to the second sensitive platform (6) is equal to the force to be measured F applied by the second micro-propeller (8). 待测 The interference force F exerted by the 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 measured force + the interference force is calculated by the following formula: F 合力 =F4=-k c2 I2 In the formula, k c2 is the second closed-loop calibration coefficient, and I2 is the current flowing into the second conductor.

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