Ground detection method and device for detecting mass release impulse and impulse moment
By designing a detection device including a suspended wire and a pendulum, combined with an autocollimator and a capacitive displacement sensor, the problem of high-precision detection of the six degrees of freedom movement of a spatial inertial sensor after its release in the existing technology is solved, and accurate evaluation of the impulse and impulse moment is achieved.
Patent Information
- Application Number
- CN202510719678.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-09-23
AI Technical Summary
Existing ground testing methods make it difficult to simulate and detect the six degrees of freedom motion of space inertial sensors after release with high precision. In particular, the measurement accuracy of release impulse and impulse moment is limited, which cannot meet the evaluation requirements of space inertial sensors after on-orbit release.
A detection device was designed, which included a primary suspension wire, a primary pendulum, a secondary suspension wire, a secondary pendulum, a detection module, and a locking or releasing module. The motion of the primary and secondary pendulums was detected by the detection module, and the impulse and impulse moment were calculated based on the motion equation. An autocollimator and a capacitive displacement sensor were used for precise measurement.
It achieves high-precision detection of the six degrees of freedom motion of the space inertial sensor after release, can accurately evaluate the impulse and impulse moment, and meet the testing requirements of the space inertial sensor after on-orbit release.
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Figure CN120686377A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of space inertial sensor testing, and more particularly to a ground detection method and device for testing mass release impulse and impulse moment. Background Art
[0002] With the continuous advancement of aerospace technology, especially in areas such as space gravitational wave detection and global gravity field measurement, the precision requirements for space inertial sensors are becoming increasingly stringent, requiring their acceleration disturbance noise to be reduced to extremely low levels. Given that Newton's second law states that under the same disturbance force, acceleration noise is inversely proportional to mass, high-precision space inertial sensors often use test masses exceeding kilograms. However, this brings with it the need for locking during launch to avoid vibration damage, as well as extremely low requirements for impulse and impulse moment during release from space to prevent collisions between the test mass and the plate.
[0003] Because space inertial sensors are in a weightless state upon release, and ground-based testing is subject to the influence of gravity, existing testing methods—whether using filament suspension, three-axis decoupled pendulum suspension, or a drop capsule to simulate a microgravity environment—struggle to fully and accurately simulate and detect the actual motion of the sensor after release. In particular, these methods struggle to achieve high-precision detection of six degrees of freedom (DOF) motion in a terrestrial gravity environment, and their accuracy in measuring the release impulse and impulse moment is limited. Therefore, there is an urgent need to develop new ground-based testing methods to more accurately assess the six degrees of freedom (DOF) impulse and impulse moment of space inertial sensors after in-orbit release, thereby promoting the further development and application of related technologies. Summary of the Invention
[0004] In order to overcome at least one of the defects of the prior art described above, the present invention provides a ground detection method and device for testing the release impulse and impulse moment of a test mass.
[0005] The present invention aims to solve the above technical problems at least to a certain extent.
[0006] In order to solve the above technical problems, the technical solutions of the present invention are as follows: A ground detection device for testing mass release impulse and impulse moment, comprising: a primary suspension wire, a primary pendulum, a secondary suspension wire, a secondary pendulum, a detection module and a locking or releasing module, wherein one end of the primary suspension wire is connected to the primary pendulum, and the other end of the primary suspension wire is installed at a fixed point, one end of the primary pendulum is connected to the secondary suspension wire, and the secondary pendulum is connected to the secondary suspension wire. A locking and releasing module is provided on the secondary pendulum, and the locking and releasing module is used to lock or release the secondary pendulum at a preset position, and the detection module is used to detect the movement of the primary pendulum and the secondary pendulum.
[0007] Preferably, the detection module includes an autocollimator and a reflector, the autocollimator faces the direction of the primary pendulum, and the reflector is arranged in the direction of the autocollimator.
[0008] Preferably, the detection module further includes a capacitive displacement sensor and an operating table, and the capacitive displacement sensor is installed on each side of the secondary pendulum and the operating table.
[0009] Preferably, the primary pendulum comprises a crossbar and a balancing mass, and the balancing mass is arranged at one end away from the crossbar.
[0010] Preferably, the detection device also includes a vacuum container, and the primary suspension wire, primary pendulum, secondary suspension wire, secondary pendulum and locking and releasing module are all arranged in the vacuum container, and the other end of the primary suspension wire is fixed to a fixed point on one side of the vacuum container.
[0011] A ground detection method for testing the release impulse and impulse moment of a mass, the detection method being applied to the detection device, comprising the following steps: S1: releasing the secondary pendulum at a preset position through the locking and releasing module, and the secondary pendulum drives the primary pendulum to move through the secondary suspension wire and the primary suspension wire; S2: Detecting the motion of the primary pendulum and the secondary pendulum during the release process through a detection module, and calculating the eigenmode frequencies of the primary pendulum and the secondary pendulum at each degree of freedom based on the motion of the primary pendulum and the secondary pendulum during the release process; S3: According to the eigenmodal frequencies of the primary pendulum and the secondary pendulum at each degree of freedom, the impulse and impulse moment of the primary pendulum and the secondary pendulum at each degree of freedom are obtained.
[0012] Preferably, in step S2, detecting the movement of the primary pendulum and the secondary pendulum during the release process by a detection module includes: The angular displacement of the primary pendulum is measured by an autocollimator and the displacement of the secondary pendulum is measured by a capacitive displacement sensor.
[0013] Preferably, in step S2, the step of calculating the eigenmodal frequencies of the primary pendulum and the secondary pendulum at each degree of freedom according to the motion conditions of the primary pendulum and the secondary pendulum during the release process comprises the following steps: S2.1: Use the detection module to detect the movement of the primary and secondary pendulums in the time domain during the release process:
[0014] in, is the mass of the first-stage pendulum, is the mass of the secondary pendulum, is the acceleration due to gravity, First-order pendulum winding y Axis deflection angle ， For the secondary swing in time Orbiting its own center of mass y Axis deflection angle ， For the first level, place it in time The deflection angle of the x-axis around its own center of mass ， ， is the horizontal distance between the center of mass of the first pendulum and the total center of mass, is the horizontal distance between the center of mass of the secondary pendulum 9 and the total center of mass, is the difference between the height of the center of mass of the first-stage pendulum and the height of the lower suspension point of the first-stage pendulum (the top of the secondary wire), is the torsional stiffness of the primary pendulum suspension wire, is the torsional stiffness of the secondary pendulum suspension wire, is the moment of inertia of the primary pendulum about the x-axis of its own center of mass, is the moment of inertia of the primary pendulum about the y-axis of its own center of mass, is the moment of inertia of the primary pendulum about the z-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the x-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the y-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the z-axis of its own center of mass, is the deflection angle of the primary wire around the y-axis at time t, The secondary wire is wound around the y-axis at time t The deflection angle, The first-order wire is wound around the x-axis at time t The deflection angle, is the deflection angle of the secondary wire around the y-axis at time t, is the deflection angle of the primary pendulum around its own center of mass on the x-axis at time t, The y-axis of the primary pendulum around its own center of mass at time t The deflection angle, The z-axis of the primary pendulum around its own center of mass in time t The deflection angle, The x-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The y-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The z-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The center of mass of the first-order pendulum is x Axis direction in time t The displacement of The center of mass of the first-order pendulum isy Axis direction in time t The displacement of The center of mass of the secondary pendulum is x Axis direction in time t The displacement of The center of mass of the first-order pendulum is in the y-axis direction at time t displacement of S2.2: Convert the system of motion equations expressed in the time domain into a system of modal equations expressed in the frequency domain as the motion situation expressed in the frequency domain:
[0015] in, is the parameter of angular frequency; S2.3: Convert the modal equations expressed in the frequency domain into a modal matrix and solve the secular equation of the modal matrix to obtain the eigenmodal frequencies of the primary and secondary pendulums at each degree of freedom:
[0016] in, is the modal matrix, is the force on the x-axis acting on the primary pendulum, is the force on the y-axis acting on the primary pendulum, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the force on the secondary pendulum in the x-axis direction, is the force on the secondary pendulum in the y-axis direction, is the torque on the secondary pendulum in the direction of rotation around the center of mass, is the torque on the secondary pendulum in the y-axis rotation direction around the center of mass, is the torque on the secondary pendulum in the direction of rotation about the center of mass along the z-axis.
[0017] Preferably, the impulse and impulse moment are calculated according to the signal amplitude, including: After selecting the amplitude of the motion response signal of the measured degree of freedom, the impulse and impulse moment on each degree of freedom are combined with the relationship between the motion response of each degree of freedom of the secondary pendulum system to obtain the impulse and impulse moment on the specific degree of freedom. .
[0018] Preferably, before step S1, the process further includes adjusting the secondary pendulum to a preset position, where the preset position is the initial position of each degree of freedom of movement of the secondary pendulum.
[0019] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: The present invention includes a primary suspension wire, a primary pendulum, a secondary suspension wire, a secondary pendulum, a detection module and a locking or releasing module. One end of the primary suspension wire is connected to the primary pendulum, and the other end of the primary suspension wire is installed at a fixed point. One end of the primary pendulum is connected to the secondary suspension wire, and the secondary pendulum is connected to the secondary suspension wire. A locking and releasing module is provided on the secondary pendulum. The locking and releasing module is used to lock or release the secondary pendulum at a preset position. The detection module is used to detect the movement of the primary pendulum and the secondary pendulum. By simultaneously detecting the movement of the two pendulums in different directions, the impulse and impulse moment of the corresponding degree of freedom are calculated according to the motion equation of the secondary pendulum system in response to external force. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 Schematic diagram of the ground detection device for the test mass release impulse and impulse moment according to the present invention; Figure 2 Schematic diagram of the ground detection device for the test mass release impulse and impulse moment according to this embodiment; Figure 3 This is a flow chart of the ground detection method for inspection mass release impulse and impulse moment described in the present invention. DETAILED DESCRIPTION
[0021] The accompanying drawings are for illustrative purposes only and are not to be construed as limiting this patent; In order to better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product size; It is understandable to those skilled in the art that some well-known structures and descriptions thereof may be omitted in the drawings.
[0022] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.
[0023] Example 1 A ground detection device for testing the release impulse and impulse moment of a test mass, such as Figure 1 As shown, it includes: a primary suspension wire 2, a primary pendulum 4, a secondary suspension wire 8, a secondary pendulum 9, a detection module and a locking or releasing module 10, one end of the primary suspension wire 2 is connected to the primary pendulum 4, the other end of the primary suspension wire 2 is installed at a fixed point, one end of the primary pendulum 4 is connected to the secondary suspension wire 8, and the secondary pendulum 9 is connected to the secondary suspension wire 8. A locking and releasing module 10 is provided on the secondary pendulum 9, and the locking and releasing module 10 is used to lock or release the secondary pendulum 9 at a preset position, and the detection module is used to detect the movement of the primary pendulum 4 and the secondary pendulum 9.
[0024] During the specific implementation process, the primary suspension wire 2 is suspended through a fixed point, which can be used to adjust the torsion angle of the primary suspension wire 2. The primary pendulum 4 is suspended above and below the primary suspension wire 2, and the extension line of the primary suspension wire 2 passes through the center of mass of the pendulum system to ensure stable suspension. The secondary pendulum 9 is suspended below the secondary suspension wire 8, and together with the locking or releasing device 10, it constitutes the object to be measured of the present invention. The detection module is used to measure the movement of different degrees of freedom of the pendulum system as input data for calculating and testing the release impulse and impulse moment.
[0025] In this embodiment, the present invention locks the secondary pendulum 9 through the locking or releasing device 10, adjusts the secondary pendulum 9 to the equilibrium position of each degree of freedom of motion, releases the test mass, measures the motion signals of each degree of freedom, and then extracts the impulse and impulse moment from the translational and rotational signals of the secondary pendulum system.
[0026] Example 2 This embodiment, based on the first embodiment, further discloses the following contents: like Figure 2 As shown, the detection module includes an autocollimator 11 and a reflector 7 . The autocollimator 11 faces the direction of the primary pendulum 4 , and the reflector 7 is arranged in the direction of the autocollimator 11 .
[0027] In this embodiment, during the measurement process, the autocollimator observes and measures the changes in the image position of the reflected light in the eyepiece to infer the slight inclination of the reflector relative to the plane perpendicular to the optical axis. The magnitude of this inclination is proportional to the deflection angle of the reflected light, so the degree of mirror tilt can be accurately determined by measuring the deflection angle.
[0028] The detection module further includes a capacitive displacement sensor 12 and an operating table 13 . The capacitive displacement sensor 12 is installed on one side of the secondary pendulum 9 and the operating table 13 .
[0029] During the specific implementation process, since the horizontal movement of the secondary pendulum along the direction perpendicular to the crossbar will cause the primary pendulum to twist around the torsion wire, and these two motion signals can be measured simultaneously using an autocollimator and a capacitive displacement sensor, the two can be verified against each other. Considering that the angle measurement of the autocollimator has a high relative accuracy, it is used to calibrate the displacement measurement accuracy of the capacitive displacement sensor in this direction. The autocollimator 11 and the six-degree-of-freedom capacitive displacement sensor 12 cooperate with each other to measure the motion of the pendulum system with different degrees of freedom, which serves as input data for calculating the test release impulse and impulse moment. The operating table 13 is used to adjust the relative position and posture of the locking release mechanism and the test mass 10 to reduce the system error caused by the initial release position.
[0030] The primary pendulum 4 includes a crossbar 5 and a balancing mass 6 , wherein the balancing mass 6 is arranged at an end away from the crossbar 5 .
[0031] In this embodiment, the primary pendulum 4 is composed of a crossbar 5 and a balancing mass 6. A reflector 7 is adhered to the center of the crossbar 5 and can be used in conjunction with an autocollimator 11 to measure the torsion angle of the primary pendulum 4.
[0032] In this embodiment, due to the different motion modes, the instruments used to measure the motion state are also different: the horizontal motion of the secondary pendulum along the direction perpendicular to the crossbar is measured using a capacitive displacement sensor, while the torsion of the primary pendulum around the torsion wire is measured using an autocollimator, so the measurements of these two motions can be verified against each other.
[0033] Example 3 This embodiment, based on Embodiments 1 and 2, further discloses the following contents: The detection device also includes a vacuum container 1, and the primary suspension wire 2, primary pendulum 4, secondary suspension wire 8, secondary pendulum 9 and locking and releasing module 10 are all arranged in the vacuum container 1, and the other end of the primary suspension wire 2 is fixed to a fixed point on one side of the vacuum container 1.
[0034] During the specific implementation process, according to the magnitude of the ground vibration in the experimental environment of the test system, the first-level suspension wire 2 is suspended in the vacuum container through a fixed point. If necessary, a magnetic damping unit can be added between the first-level suspension wire 2 and the fixed point to suppress the simple pendulum effect caused by the ground vibration.
[0035] Example 4 This embodiment further discloses the following contents based on Embodiments 1, 2, and 3: A ground detection method for testing the mass release impulse and impulse moment, such as Figure 3 As shown, the detection method is applied to the detection device, comprising the following steps: S1: Release the secondary pendulum 9 at a preset position through the locking and releasing module 10, and the secondary pendulum 9 drives the primary pendulum 4 to move through the secondary suspension wire 8 and the primary suspension wire 2; S2: detecting the motion of the primary pendulum 4 and the secondary pendulum 9 during the release process through a detection module, and calculating the eigenmode frequencies of the primary pendulum 4 and the secondary pendulum 9 in each degree of freedom according to the motion of the primary pendulum 4 and the secondary pendulum 9 during the release process; S3: According to the eigenmodal frequencies of the primary pendulum 4 and the secondary pendulum 9 in each degree of freedom, the impulse and impulse moment of the primary pendulum 4 and the secondary pendulum 9 in each degree of freedom are obtained.
[0036] In the specific implementation process, first, the secondary pendulum 9 is released at a preset position through the locking and releasing module 10, and the secondary pendulum 9 drives the primary pendulum 4 to move through the secondary suspension wire 8 and the primary suspension wire 2; Then, the detection module detects the motion of the primary pendulum 4 and the secondary pendulum 9 during the release process, and calculates the eigenmode frequencies of the primary pendulum 4 and the secondary pendulum 9 in each degree of freedom based on the motion of the primary pendulum 4 and the secondary pendulum 9 during the release process; Then, the impulse and impulse moment of the primary pendulum 4 and the secondary pendulum 9 at each degree of freedom are obtained according to the eigenmodal frequencies of the primary pendulum 4 and the secondary pendulum 9 at each degree of freedom; This embodiment obtains the impulse and impulse moment of the corresponding degree of freedom of the secondary pendulum by extracting the impulse and impulse moment from the translational and rotational signals of the secondary pendulum.
[0037] Example 5 This embodiment, based on Embodiments 1, 2, 3, and 4, further discloses the following contents: In step S2, the eigenmodal frequencies of the primary pendulum (4) and the secondary pendulum (9) at each degree of freedom are calculated based on the motion conditions of the primary pendulum (4) and the secondary pendulum (9) during the release process, including the following steps: S2.1: Detect the movement of the primary pendulum 4 and the secondary pendulum 9 during the release process in the time domain using the detection module:
[0038] in, is the mass of the first-stage pendulum, is the mass of the secondary pendulum, is the acceleration due to gravity, First-order pendulum winding y Axis deflection angle ， For the secondary swing in time Orbiting its own center of mass y Axis deflection angle ， For the first level, place it in time The deflection angle of the x-axis around its own center of mass ， ， is the horizontal distance between the center of mass of the first pendulum and the total center of mass, is the horizontal distance between the center of mass of the secondary pendulum 9 and the total center of mass, is the difference between the height of the center of mass of the first-stage pendulum and the height of the lower suspension point of the first-stage pendulum (the top of the secondary wire), is the torsional stiffness of the primary pendulum suspension wire, is the torsional stiffness of the secondary pendulum suspension wire, is the moment of inertia of the primary pendulum about the x-axis of its own center of mass, is the moment of inertia of the primary pendulum about the y-axis of its own center of mass, is the moment of inertia of the primary pendulum about the z-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the x-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the y-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the z-axis of its own center of mass, is the deflection angle of the primary wire around the y-axis at time t, The secondary wire is wound around the y-axis at time t The deflection angle, The first-order wire is wound around the x-axis at time t The deflection angle, is the deflection angle of the secondary wire around the y-axis at time t, is the deflection angle of the primary pendulum around its own center of mass on the x-axis at time t, The y-axis of the primary pendulum around its own center of mass at time t The deflection angle, The z-axis of the primary pendulum around its own center of mass in time t The deflection angle, The x-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The y-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The z-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The center of mass of the first-order pendulum is x Axis direction in time t The displacement of The center of mass of the first-order pendulum is y Axis direction in time t The displacement of The center of mass of the secondary pendulum is x Axis direction in time t The displacement of The center of mass of the first-order pendulum is in the y-axis direction at time t displacement of S2.2: Convert the system of motion equations expressed in the time domain into a system of modal equations expressed in the frequency domain as the motion situation expressed in the frequency domain:
[0039] in, is the parameter of angular frequency; In step S2, the eigenmodal frequencies of the primary pendulum 4 and the secondary pendulum 9 at each degree of freedom are calculated based on the motion of the primary pendulum 4 and the secondary pendulum 9 during the release process, including: S2.3: Convert the modal equations expressed in the frequency domain into a modal matrix and solve the secular equation of the modal matrix to obtain the eigenmodal frequencies of the primary pendulum 4 and the secondary pendulum 9 in each degree of freedom:
[0040] in, is the modal matrix, is the force on the x-axis acting on the primary pendulum, is the force on the y-axis acting on the primary pendulum, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the force on the secondary pendulum in the x-axis direction, is the force on the secondary pendulum in the y-axis direction, is the torque on the secondary pendulum in the direction of rotation around the center of mass, is the torque on the secondary pendulum in the y-axis rotation direction around the center of mass, is the torque on the secondary pendulum in the direction of rotation about the center of mass along the z-axis.
[0041] In step S3, the impulse and impulse moment of the primary pendulum 4 and the secondary pendulum 9 at each degree of freedom are obtained based on the signal amplitude of the primary pendulum 4 and the secondary pendulum 9 at each degree of freedom, including: According to the eigenmode frequencies of the primary pendulum 4 and the secondary pendulum 9 in each degree of freedom, the corresponding signal amplitudes are obtained by solving the motion equations, and then the impulse or impulse moment is obtained by calculating the signal amplitudes. Before step S1 , the process also includes adjusting the secondary pendulum 9 to a preset position, where the preset position is the initial position of each degree of freedom of the secondary pendulum 9 .
[0042] In the specific implementation process, according to the above-designed two-stage pendulum system, the mass of the first-stage pendulum including the crossbar 5, the balancing mass 6, and the reflector 7 is , the mass of the secondary pendulum 9 is , the horizontal distance between the center of mass of the first pendulum and the total center of mass is , the horizontal distance between the center of mass of the secondary pendulum 9 and the total center of mass is , the length of the first pendulum is , the length of the secondary pendulum is , the difference between the height of the first-stage pendulum's lower hanging point and the height of the first-stage pendulum's center of mass is The difference between the height of the secondary pendulum 9's lower hanging point and the height of the secondary pendulum's center of mass is The difference between the height of the center of mass of the first-stage pendulum and the height of the lower suspension point of the first-stage pendulum (the top of the secondary wire) is , the torsional stiffness of the primary pendulum suspension wire 2 is , the torsional stiffness of the secondary pendulum suspension wire 8 is .
[0043] Considering the large stiffness in the extension direction of the suspension wire, its change can be ignored in the test. The secondary pendulum system has a total of ten degrees of freedom, which are the displacement of the primary pendulum along the x-axis and the y-axis. and , the deflection angles of the primary pendulum around the lower suspension point of wire 2 along the x-axis, y-axis, and z-axis 、 and , the displacement of the secondary pendulum along the x-axis and y-axis and The deflection angles of the secondary pendulum around the lower suspension point of the suspension wire 8 are x-axis, y-axis and z-axis. 、 and , assuming the suspension point position , we can get that the height changes of the center of mass of the primary pendulum system and the secondary pendulum system satisfy the following relationship:
[0044]
[0045]
[0046] is the height of the center of mass of the first-stage pendulum, is the height of the center of mass of the secondary pendulum, and the length of the primary pendulum wire is , the length of the secondary pendulum wire is , is the deflection angle of the primary pendulum around the x-axis, is the deflection angle of the primary pendulum around the y-axis, is the deflection angle of the primary pendulum around the z-axis, is the height from one end of the first pendulum to the center of crossbar 5, is the horizontal distance between the center of mass of the first pendulum and the total center of mass, is the horizontal distance between the center of mass of the secondary pendulum 9 and the total center of mass, is the height from the lower suspension point of the secondary pendulum 9 to the center of the test mass, is the deflection angle of the secondary pendulum around the x-axis, is the deflection angle of the secondary pendulum around the y-axis, is the deflection angle of the secondary pendulum around the z-axis; The total kinetic energy of the system includes the translational kinetic energy, rotational kinetic energy, gravitational potential energy, and elastic potential energy of the suspension wire of the secondary pendulum system. Substituting the above parameters into the expressions of kinetic energy and potential energy of each degree of freedom of the system, we can obtain the kinetic energy and potential energy of the system as a function of each parameter and time. t The expression of the change:
[0047]
[0048] in and represents the velocity of the center of mass of the primary and secondary pendulums as they change with time. The total potential energy of the system is:
[0049] Finally, the Lagrangian of the system is obtained as:
[0050]
[0051]
[0052]
[0053] Substitute the Lagrangian of the system into the Lagrangian equation:
[0054] The generalized coordinates q Represent the ten degrees of freedom of motion parameters of the secondary pendulum mentioned above 、 、 、 、 、 、 、 、 、 , we can get the motion equations of each degree of freedom of the system:
[0055] in
[0056] Select the first-stage pendulum center of mass translation 、 and rotation around the z axis , and the translation of the center of mass of the secondary pendulum 、 and rotation around the z axis As an independent parameter describing the system state, the corresponding initial conditions are added to the above differential equations and then solved. For example, it is assumed that there is an initial impulse on the x degree of freedom, and the impulses or impulse moments in other directions are all 0. In actual calculations, the initial conditions added are in the form of velocity or angular velocity. The relationship between the impulses and impulse moments of the three translational degrees of freedom and three rotational degrees of freedom generated by the test mass after the release of the test mass and the motion response of each degree of freedom of the secondary pendulum system is obtained.
[0057] The impulse and impulse moment are calculated based on the signal amplitude, including: After selecting the amplitude of the motion response signal of the measured degree of freedom, the impulse and impulse moment on each degree of freedom are combined with the relationship between the motion response of each degree of freedom of the secondary pendulum system to obtain the impulse and impulse moment on the specific degree of freedom.
[0058] The parameters in the brackets are all the parameters that affect the motion function of the degree of freedom. Specifically, for the motion of a certain degree of freedom, For example, it can be expressed as follows:
[0059] After selecting the amplitude of the motion response signal of the measured degree of freedom, the impulse and impulse moment on each degree of freedom are combined with the relationship between the obtained impulse and impulse moment on each degree of freedom and the motion response of each degree of freedom of the secondary pendulum system to obtain the impulse and impulse moment on the specific degree of freedom.
[0060] To verify the test results, the velocity or angular velocity corresponding to the impulse and impulse moment on the six degrees of freedom received by the test mass after release can be used as the initial condition. The independent parameters can be determined in the existing system motion equations for each degree of freedom and then solved. The motion response of each degree of freedom obtained can be compared with the motion measured by the autocollimator and capacitive displacement sensor to determine the reliability of the measurement and calculation.
[0061] Example 6 This embodiment, based on Embodiments 1, 2, 3, 4, and 5, further discloses the following contents: Before testing, the test system is assembled. Specifically, a turntable or vacuum guide is placed in a vacuum container 1, from which a primary wire 2 is suspended. Below this wire 2 is a primary pendulum 4, consisting of a crossbar 5, a balancing mass 6, and a reflector 7 attached to the crossbar 5. The extension of wire 2 passes through the center of mass of the pendulum system. A secondary wire 8 is suspended from the other end of the crossbar 5, and below this is a secondary pendulum 9 (the test mass). A locking and release mechanism 10 and an operating platform 13 are installed on the secondary pendulum 9. Additionally, an autocollimator 11 and a six-degree-of-freedom capacitive displacement sensor 12 are installed to measure the motion of the pendulum system.
[0062] Measure the geometric and mass parameters of the device, the mass of the first pendulum , secondary pendulum mass , the horizontal distance between the center of mass of the first pendulum and the total center of mass , the horizontal distance between the center of mass of the first pendulum and the total center of mass , first and second pendulum length , the height from the first-stage pendulum's lower suspension point to the first-stage pendulum's center of mass , the height from the lower suspension point of the secondary pendulum to the center of mass of the secondary pendulum , the difference between the height of the center of mass of the primary pendulum and the height of the lower suspension point of the primary pendulum (the top of the secondary wire) , the torsional stiffness of the two wires Substitute the above data into the Lagrangian of the system , and then substitute into the Lagrange equation In the equation , the eigenmode frequencies of the motion signals at each degree of freedom are obtained:
[0063] in The movement is mainly composed of Caused, therefore The eigenmode frequency of Same value.
[0064] At the beginning of the experiment, the test mass is first locked and adjusted to the equilibrium position of each degree of freedom through the operating table. The test mass is then released and the motion signals of each degree of freedom are measured. The signal amplitude at the main motion modal frequency in each direction is extracted and substituted into the relationship between the impulse or impulse moment in each direction obtained from the aforementioned set of motion equations and the displacement or angular displacement response of the two-stage pendulum system in different degrees of freedom. The release impulse and impulse moment of the six degrees of freedom of the test mass can be calculated. For example, if the displacement detection capability of each degree of freedom is 100 nm and the angular displacement detection capability is 100 nrad, the accuracy of the corresponding system detection of impulse and impulse moment is: When the displacement detection capability is 100nm, the corresponding impulse detection accuracy is: (unit: )
[0065] The impulse moment detection accuracy when the angular displacement detection capability is 100 nrad is: (unit: )
[0066] As one specific embodiment, the horizontal movement of the secondary pendulum along the direction perpendicular to the crossbar will also cause the primary pendulum to twist around the torsion wire. The impulse in the direction can be generated not only by the secondary pendulum center of mass in z The displacement calculation in the direction can also be done by Calculation of torsion in direction: When the first pendulum angular displacement Detection capabilities The corresponding impulse detection accuracy is When measuring the center of mass of the secondary pendulum z When the displacement in the direction of z The impulse in the direction of zThe initial velocity in the direction of the secondary pendulum is measured using a capacitive displacement sensor. z The displacement in the direction is measured. Based on the displacement measurement, the impulse or impulse moment in each direction obtained by solving the motion equations of the secondary pendulum system and the relationship between the displacement or angular displacement response of the secondary pendulum system in different degrees of freedom can be calculated to obtain the initial impulse applied to the secondary pendulum. z After the impulse in the direction, it is also necessary to use the first level of the autocollimator The angular displacement in each direction is measured simultaneously with the displacement measured using a capacitive displacement sensor. Based on this angular displacement measurement and the relationship between the impulse or impulse moment applied in each direction and the resulting displacement or angular displacement response, the initial impulse applied to the secondary pendulum can also be calculated. Since the displacement or angular displacement measured in both directions is caused by the same impulse, the impulse magnitudes calculated in both calculations should be consistent.
[0067] After determining the independent parameters, by solving the time domain equations with the initial conditions added, the motion of each degree of freedom of the experimental device after being subjected to a specific impulse or impulse moment can be obtained (for example, after determining the mass of the first pendulum, the initial velocity or initial angular velocity of other degrees of freedom is set to 0 in the initial conditions, and the first pendulum is x Initial velocity in direction For a specific value, you can Get a first-level pendulum x The impulse in the direction, and the impulse or impulse moment in other degrees of freedom are the same. Since the motion in a certain degree of freedom is obtained by the superposition of multiple motions, this motion is Fourier transformed to obtain the corresponding frequencies of these motions and the peak values on the frequency domain graph. The frequency domain and peak values are then used to obtain the motion amplitude at each frequency after the motion is decomposed into multiple frequencies. According to the form of the time domain equations, the initial conditions are proportional to the motion amplitude at a specific frequency after the motion in a specific degree of freedom is decomposed. The initial impulse or impulse moment received by the experimental device can be calculated using the initial conditions (initial velocity or initial angular velocity) and the parameters of the experimental device itself (including mass and moment of inertia). Therefore, the initial impulse or impulse moment received by the experimental device is also proportional to the motion amplitude at a specific frequency after the motion in a specific degree of freedom is decomposed. By solving the motion equation in the time domain and combining this proportional relationship, we can determine the specific functional relationship between the initial impulse or impulse moment received by the experimental device and the motion amplitude of a specific frequency after decomposing the motion conditions in a specific degree of freedom. Therefore, during the experiment, it is only necessary to measure the signal amplitude at the corresponding frequency of each degree of freedom to solve the six-degree-of-freedom impulse or weight moment received by the test mass after its release.
[0068] The same or similar reference numerals correspond to the same or similar components; The terms used in the drawings to describe positional relationships are for illustrative purposes only and should not be construed as limiting this patent; Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.
Claims
1. A ground detection device for testing the release impulse and impulse moment of a test mass, characterized in that: include: A primary suspension wire (2), a primary pendulum (4), a secondary suspension wire (8), a secondary pendulum (9), a detection module and a locking or releasing module (10), wherein one end of the primary suspension wire (2) is connected to the primary pendulum (4), the other end of the primary suspension wire (2) is installed at a fixed point, one end of the primary pendulum (4) is connected to the secondary suspension wire (8), the secondary pendulum (9) is connected to the secondary suspension wire (8), a locking and releasing module (10) is provided on the secondary pendulum (9), the locking and releasing module (10) is used to lock or release the secondary pendulum (9) at a preset position, and the detection module is used to detect the movement of the primary pendulum (4) and the secondary pendulum (9).
2. The ground detection device for test mass release impulse and impulse moment according to claim 1, characterized in that: The detection module comprises an autocollimator (11) and a reflector (7), wherein the autocollimator (11) faces the direction of the primary pendulum (4), and the reflector (7) is arranged in the direction of the autocollimator (11).
3. The ground detection device for testing the release impulse and impulse moment of a proof mass according to claim 2, characterized in that: The detection module further comprises a capacitive displacement sensor (12) and an operating table (13), wherein the capacitive displacement sensor (12) is mounted on one side of each of the secondary pendulum (9) and the operating table (13).
4. The ground detection device for testing the release impulse and impulse moment of a proof mass according to claim 1, characterized in that: The primary pendulum (4) comprises a crossbar (5) and a balancing mass (6), wherein the balancing mass (6) is arranged at an end away from the crossbar (5).
5. The ground detection device for testing the release impulse and impulse moment of a proof mass according to claim 1, characterized in that: The detection device further comprises a vacuum container (1), wherein the primary suspension wire (2), the primary pendulum (4), the secondary suspension wire (8), the secondary pendulum (9) and the locking and releasing module (10) are all arranged in the vacuum container (1), and the other end of the primary suspension wire (2) is fixed to a fixed point on one side of the vacuum container (1).
6. A ground detection method for testing mass release impulse and impulse moment, characterized in that: The detection method is applied to the detection device according to any one of claims 1 to 5, comprising the following steps: S1: releasing the secondary pendulum (9) at a preset position through the locking and releasing module (10), wherein the secondary pendulum (9) drives the primary pendulum (4) to move through the secondary suspension wire (8) and the primary suspension wire (2); S2: detecting the motion of the primary pendulum (4) and the secondary pendulum (9) during the release process through a detection module, and calculating the eigenmodal frequencies of the primary pendulum (4) and the secondary pendulum (9) at each degree of freedom according to the motion of the primary pendulum (4) and the secondary pendulum (9) during the release process; S3: According to the eigenmodal frequencies of the primary pendulum (4) and the secondary pendulum (9) at each degree of freedom, the impulse and impulse moment of the primary pendulum (4) and the secondary pendulum (9) at each degree of freedom are obtained.
7. The ground detection method for proof mass release impulse and impulse moment according to claim 6, characterized in that: In step S2, the eigenmodal frequencies of the primary pendulum (4) and the secondary pendulum (9) at each degree of freedom are calculated based on the motion conditions of the primary pendulum (4) and the secondary pendulum (9) during the release process, including the following steps: S2.1: Establish a motion situation in the time domain: in, is the mass of the first-stage pendulum, is the mass of the secondary pendulum, is the acceleration due to gravity, First-order pendulum winding y Axis deflection angle ， For the secondary swing in time Orbiting its own center of mass y Axis deflection angle ， For the first level, place it in time The deflection angle of the x-axis around its own center of mass ， ， is the horizontal distance between the center of mass of the first pendulum and the total center of mass, is the horizontal distance between the center of mass of the secondary pendulum 9 and the total center of mass, is the difference between the height of the center of mass of the first-stage pendulum and the height of the lower suspension point of the first-stage pendulum (the top of the secondary wire), is the torsional stiffness of the primary pendulum suspension wire, is the torsional stiffness of the secondary pendulum suspension wire, is the moment of inertia of the primary pendulum about the x-axis of its own center of mass, is the moment of inertia of the primary pendulum about the y-axis of its own center of mass, is the moment of inertia of the primary pendulum about the z-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the x-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the y-axis of its own center of mass, is the moment of inertia of the secondary pendulum about the z-axis of its own center of mass, is the deflection angle of the primary wire around the y-axis at time t, The secondary wire is wound around the y-axis at time t The deflection angle, The first-order wire is wound around the x-axis at time t The deflection angle, is the deflection angle of the secondary wire around the y-axis at time t, is the deflection angle of the primary pendulum around its own center of mass on the x-axis at time t, The y-axis of the primary pendulum around its own center of mass at time t The deflection angle, The z-axis of the primary pendulum around its own center of mass in time t The deflection angle, The x-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The y-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The z-axis of the secondary pendulum around its own center of mass at time t The deflection angle, The center of mass of the first-order pendulum is x Axis direction in time t The displacement of The center of mass of the first-order pendulum is y Axis direction in time t The displacement of The center of mass of the secondary pendulum is x Axis direction in time t The displacement of The center of mass of the first-order pendulum is in the y-axis direction at time t displacement of S2.2: Convert the system of motion equations expressed in the time domain into a system of modal equations expressed in the frequency domain as the motion situation expressed in the frequency domain: in, is the parameter of angular frequency; S2.3: Convert the modal equations expressed in the frequency domain into a modal matrix, and solve the secular equation of the modal matrix to obtain the eigenmodal frequencies of the primary pendulum (4) and the secondary pendulum (9) in each degree of freedom: in, is the modal matrix, is the force on the x-axis acting on the primary pendulum, is the force on the y-axis acting on the primary pendulum, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the torque on the primary pendulum in the direction of rotation around the center of mass, is the force on the secondary pendulum in the x-axis direction, is the force on the secondary pendulum in the y-axis direction, is the torque on the secondary pendulum in the direction of rotation around the center of mass, is the torque on the secondary pendulum in the y-axis rotation direction around the center of mass, is the torque on the secondary pendulum in the direction of rotation about the center of mass along the z-axis.
8. The ground detection method for proof mass release impulse and impulse moment according to claim 8, characterized in that: In step S3, the impulse and impulse moment of the primary pendulum (4) and the secondary pendulum (9) at each degree of freedom are obtained based on the signal amplitude of the primary pendulum (4) and the secondary pendulum (9) at each degree of freedom, including: The motion equations are solved according to the eigenmode frequencies of the primary pendulum (4) and the secondary pendulum (9) at each degree of freedom to obtain the corresponding signal amplitudes, and then the impulse and impulse moment are calculated based on the signal amplitudes.
9. The ground detection method for proof mass release impulse and impulse moment according to claim 8, characterized in that: The impulse and impulse moment are calculated based on the signal amplitude, including: After selecting the amplitude of the motion response signal of the measured degree of freedom, the impulse and impulse moment on each degree of freedom are combined with the relationship between the motion response of each degree of freedom of the secondary pendulum system to obtain the impulse and impulse moment on the specific degree of freedom. 。 10. The ground detection method for proof mass release impulse and impulse moment according to claim 6, characterized in that: Before step S1, the second pendulum (9) is also adjusted to a preset position, wherein the preset position is the initial position of each degree of freedom of movement of the second pendulum (9).