Angular vibration calibration apparatus and method for tri-axial magneto fluid angular rate sensor

Abstract

The application provides an angular vibration calibration device and method for a three-axis magnetic fluid angular velocity sensor, and belongs to the technical field of inertial test equipment and precise optical measurement. The angular vibration calibration device comprises a three-axis angular vibration turntable, a measured tooling, a multi-channel probe array and a processing module. The three-axis angular vibration turntable is configured to apply multiple angular vibration excitations to the measured tooling. The three-axis magnetic fluid angular velocity sensor to be calibrated is configured to output multiple angular velocity measurement data related to each angular vibration excitation. The multi-channel probe array is configured to emit multiple laser beams to the measured tooling, and receive multiple reflected laser beams formed by the multiple laser beams reflected by the measured tooling, so as to obtain multiple linear velocity measurement data related to each angular vibration excitation. The processing module is configured to obtain a calibration result of the three-axis magnetic fluid angular velocity sensor to be calibrated based on the multiple angular velocity measurement data and the multiple linear velocity measurement data related to each of the multiple angular vibration excitations.

Description

Technical Field

[0001] This invention relates to the fields of inertial testing equipment and precision optical measurement technology, and more specifically, to an angular vibration calibration device and method for a triaxial magnetohydrodynamic angular velocity sensor. Background Technology

[0002] Triaxial Magnetohydrodynamic Angular Rate Sensor (MHD-ARS) has been widely used in aerospace, weapon guidance, and measurement while drilling due to its advantages such as wide bandwidth, high dynamic response, and no moving parts.

[0003] Cross-coupling error is a core factor affecting the accuracy of triaxial MHD-ARS measurements. However, existing angular vibration calibration techniques suffer from technical problems when used to measure cross-coupling error, such as single-axis geometric locking, phase aliasing of translational and rotational signals, and mutual constraints between large range and high-frequency response measurements. Summary of the Invention

[0004] In view of this, the present invention provides an angular vibration calibration device and method for a triaxial magnetohydrodynamic angular velocity sensor.

[0005] One aspect of the present invention provides an angular vibration calibration device for a triaxial magnetohydrodynamic (MHD) angular velocity sensor, comprising a triaxial angular vibration turntable, a test fixture, a multi-channel probe array, and a processing module. The test fixture is fixedly mounted on the triaxial angular vibration turntable and configured to hold the triaxial MHD angular velocity sensor to be calibrated. The processing module is communicatively connected to both the triaxial MHD angular velocity sensor to be calibrated and the multi-channel probe array. The triaxial angular vibration turntable is configured to apply various angular vibration excitations to the test fixture. The triaxial MHD angular velocity sensor to be calibrated... The degree sensor is configured to output multiple angular velocity measurement data related to each type of angular vibration excitation; the multi-channel probe array is configured to emit multiple laser beams to the test fixture and receive multiple reflected beams formed by the multiple laser beams reflected by the test fixture, thereby obtaining multiple linear velocity measurement data related to each type of angular vibration excitation; the processing module is configured to obtain the calibration result of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated by differential calibration and cross-coupling parameter identification based on the multiple angular velocity measurement data and multiple linear velocity measurement data related to each of the various angular vibration excitations.

[0006] According to an embodiment of the present invention, the processing module is configured to: perform differential calibration on the triaxial magnetohydrodynamic angular velocity sensor to be calibrated based on multiple linear velocity measurement data related to the angular vibration excitation, to obtain triaxial angular velocity reference values ​​and triaxial translational velocity reference values ​​related to the angular vibration excitation; obtain calibration samples related to the angular vibration excitation based on the triaxial angular velocity reference values, triaxial translational velocity reference values, and multiple angular velocity measurement data; and perform cross-coupling parameter identification on the triaxial magnetohydrodynamic angular velocity sensor to be calibrated based on multiple calibration samples and in conjunction with fluid coupling terms, to obtain the calibration result of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated.

[0007] According to an embodiment of the present invention, the processing module is configured to: construct an overdetermined equation system based on the principles of rigid body kinematics, multiple linear velocity measurement data, and the illumination positions of multiple laser beams on the measured fixture; solve the overdetermined equation system using the least squares method to obtain a first axial angular velocity component, a second axial angular velocity component, a third axial angular velocity component, a third axial translational component, and a coupling term error; perform inversion calculation based on the coupling term error to obtain a first axial translational component and a second axial translational component; and obtain the triaxial angular velocity reference value based on the first axial angular velocity component, the second axial angular velocity component, and the third axial angular velocity component, and obtain the triaxial translational velocity reference value based on the first axial translational component, the second axial translational component, and the third axial translational component.

[0008] According to an embodiment of the present invention, the processing module is configured to: construct a calibration model of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated based on the correlation between multiple angular velocity measurement data of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated, the triaxial angular velocity reference value, the triaxial translational velocity reference value, and the fluid coupling term; wherein the fluid coupling term includes a conductive fluid viscosity-Coriolis force flow field coupling function related to the triaxial angular velocity reference value and the triaxial translational velocity reference value; and perform linear fitting on the calibration model based on multiple calibration samples to obtain an angle-angle coupling matrix, a line-angle coupling matrix, and a fluid coupling coefficient matrix to obtain the calibration result.

[0009] According to an embodiment of the present invention, the multi-channel probe array includes a plurality of first vibration probes, a plurality of second vibration probes, and a plurality of third vibration probes; wherein, the optical axis direction of each of the plurality of first vibration probes is parallel to the third axial direction, and the line connecting the light spots formed by each of the plurality of first vibration probes on the surface of the tested fixture is parallel to the second axial direction; the optical axis direction of each of the plurality of second vibration probes is parallel to the third axial direction, and the line connecting the light spots formed by each of the plurality of second vibration probes on the surface of the tested fixture is parallel to the first axial direction; the optical axis directions of each of the plurality of third vibration probes are parallel, and the line connecting the light spots formed by each of the plurality of third vibration probes on the surface of the triaxial magnetohydrodynamic angular velocity sensor is parallel to the first axial direction; the first axial direction, the second axial direction, and the third axial direction are each orthogonal.

[0010] According to an embodiment of the present invention, a plurality of optical targets are attached to the surface of the test fixture, and the plurality of light spots formed by the multi-channel probe array on the surface of the test fixture are respectively located within the effective reflection areas of the plurality of optical targets.

[0011] According to an embodiment of the present invention, the angular vibration calibration device further includes: a camera module, communicatively connected to the processing module, configured to acquire surface images of the workpiece under test; wherein the processing module is further configured to determine, based on the surface images, the initial positions of multiple light spots formed by the multiple laser beams on the surface of the workpiece under test, and, based on the initial positions of the multiple light spots and the effective reflection areas of the multiple optical targets, adjust the pose of the multi-channel probe array and / or the pose of the triaxial angular vibration turntable so that the multiple light spots are respectively located within the effective reflection areas of the multiple optical targets.

[0012] According to an embodiment of the present invention, the above-mentioned fixture under test is configured to hold a reference vibration source, and the reference vibration source is configured to output a reference angular vibration excitation; wherein, the above-mentioned processing module is further configured to acquire multiple linear velocity data related to the reference angular vibration excitation from the above-mentioned multi-channel probe array, and to use the multiple linear velocity data to calibrate the measurement reference of the above-mentioned multi-channel probe array.

[0013] According to an embodiment of the present invention, the angular vibration calibration device further includes an environmental control component, which is arranged around the triaxial angular vibration turntable, and the multi-channel probe array is located inside the environmental control component. The environmental control component is configured to suppress ambient stray light and airflow disturbances.

[0014] Another aspect of the present invention provides an angular vibration calibration method for a triaxial magnetohydrodynamic (MHD) angular velocity sensor, applied to the angular vibration calibration device for a triaxial MHD angular velocity sensor described above. The method includes: during the process of controlling a triaxial angular vibration turntable to apply multiple angular vibration excitations to the fixture under test, acquiring multiple angular velocity measurement data output by the triaxial MHD angular velocity sensor to be calibrated related to each angular vibration excitation, and multiple linear velocity measurement data output by a multi-channel probe array related to each angular vibration excitation; and based on the multiple angular velocity measurement data and multiple linear velocity measurement data related to each of the multiple angular vibration excitations, obtaining the calibration result of the triaxial MHD angular velocity sensor to be calibrated through differential calibration and cross-coupling parameter identification.

[0015] According to an embodiment of the present invention, a triaxial angular vibration turntable is used to apply multiple angular vibration excitations to the fixture under test, causing the triaxial magnetohydrodynamic angular velocity sensor to be calibrated, held by the fixture under test, to output multiple angular velocity measurement data related to each angular vibration excitation. Simultaneously, multiple laser beams are emitted to the fixture under test through a multi-channel probe array, and multiple reflected beams formed by the multiple laser beams reflected by the fixture under test are received, obtaining multiple linear velocity measurement data related to each angular vibration excitation. Thus, based on the multiple angular velocity measurement data and multiple linear velocity measurement data related to each of the multiple angular vibration excitations, the calibration result of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated can be obtained through differential calibration and cross-coupling parameter identification. This breaks through the geometric limitations of traditional single-axis calibration, and can simultaneously measure triaxial angular velocity and triaxial translational velocity under triaxial synchronous angular vibration excitation, realistically simulating the actual working conditions of MHD-ARS, and obtaining more accurate cross-coupling parameters than the traditional axis-by-axis calibration method. Attached Figure Description

[0016] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings.

[0017] Figure 1 A schematic diagram of an angular vibration calibration device for a triaxial magnetohydrodynamic angular velocity sensor according to an embodiment of the present invention is shown.

[0018] Figure 2 A schematic diagram of an angular vibration calibration device for a triaxial magnetohydrodynamic angular velocity sensor according to another embodiment of the present invention is shown.

[0019] Figure 3 A flowchart of an angular vibration calibration method for a triaxial magnetohydrodynamic angular velocity sensor according to an embodiment of the present invention is shown. Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms "comprising," "including," etc., as used herein indicate the presence of the above-described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0022] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0023] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0024] Currently, the calibration of triaxial MHD-ARS generally adopts the traditional single-axis successive calibration scheme based on the principle of laser interferometry: excitation is applied sequentially to the X-axis, Y-axis, and Z-axis using a single-axis angular vibration table, and the principal axis sensitivity and maximum lateral sensitivity percentage of each axis are measured respectively. The physical structure corresponding to the traditional single-axis successive calibration scheme usually consists of a laser source, a beam splitter (BS), a fixed reference mirror, and a measurement mirror mounted on the angular vibration table. Its basic calibration process is as follows: First, the laser beam is split into a reference beam and a measurement beam by the BS; second, the measurement beam is projected onto the measurement mirror that moves with the rotating table. When the rotating table undergoes angular displacement, the optical path difference (OPD) of the measurement arm changes; subsequently, the two coherent beams are fed back and interference fringes are generated, and the interference signal is captured by a photodetector; finally, the OPD is converted into angular displacement using geometric mapping relationships, and then the angular velocity is calculated as the calibration reference for the MHD-ARS.

[0025] Although the above-mentioned traditional laser interferometry calibration scheme has high resolution in single-axis static or quasi-static environments, it has the following insurmountable defects for the three-axis calibration requirements of three-axis MHD-ARS.

[0026] First, it is impossible to achieve cross-coupling identification under triaxial synchronous excitation. Traditional laser interferometry calibration schemes have stringent requirements for the geometric alignment of the optical path, typically requiring the laser beam to be strictly perpendicular to the rotation axis or collinear with the rotation radius vector. This "point-to-point" interference model is physically confined to a single degree of freedom. Once triaxial synchronous angular vibration is introduced, the rotation center of the test object will drift instantaneously, causing a rapid decrease in the overlap of coherent light, leading to loss of lock (LoL). This makes it impossible to maintain fringe contrast, resulting in the failure of multi-axis synchronous decoupling measurement and making it impossible to identify cross-coupling parameters under triaxial synchronous excitation.

[0027] Second, the phase aliasing of translational and rotational motions makes it impossible to separate the line-angle coupling. In the measurement model of traditional laser interferometry calibration schemes, the detector picks up the comprehensive displacement change along the laser optical axis. When the angular vibration table is working, the mechanical system inevitably experiences minute linear vibrations (i.e., parasitic translational interference). Since existing schemes cannot physically distinguish whether the change in OPD is caused by the target's "rotation" or by "parasitic translation," the phase signals of the two are highly aliased in the time domain. Therefore, it is impossible to identify the line-angle coupling matrix of the three-axis MHD-ARS separately, resulting in a calibration error exceeding 1% in the low-frequency band.

[0028] Third, existing calibration methods cannot directly output the complete cross-coupling matrix. Existing calibration methods can only obtain the single-axis sensitivity and the percentage of maximum lateral sensitivity, but cannot obtain the complete 3×3 corner-to-corner coupling matrix and 3×3 line-to-corner coupling matrix. Therefore, it is impossible to achieve full compensation of cross-coupling error based on matrix inversion, and thus cannot meet the specific error compensation requirements of the three-axis MHD-ARS.

[0029] Therefore, a high-precision calibration scheme for cross-coupling error that can achieve synchronous measurement of triaxial angular vibration is needed to solve the unique line-angle strong coupling and triaxial flow field coupling calibration problems of triaxial MHD-ARS. That is, it is necessary to construct a measurement model with multi-degree-of-freedom decoupling capability to achieve accurate identification of cross-coupling parameters of triaxial MHD-ARS in complex dynamic environments and broadband conditions.

[0030] Figure 1 A schematic diagram of an angular vibration calibration device for a triaxial magnetohydrodynamic angular velocity sensor according to an embodiment of the present invention is shown.

[0031] like Figure 1As shown, the angular vibration calibration device for a triaxial magnetohydrodynamic (MHD) angular velocity sensor includes a triaxial angular vibration turntable 110, a test fixture 120, a multi-channel probe array 130, and a processing module 140. The test fixture 120 is fixedly mounted on the triaxial angular vibration turntable 110 and is configured to hold the triaxial MHD angular velocity sensor to be calibrated. The processing module 140 is communicatively connected to both the triaxial MHD angular velocity sensor to be calibrated and the multi-channel probe array 130.

[0032] The triaxial angular vibration turntable 110 is configured to apply various angular vibration excitations to the fixture 120 under test, and the triaxial magnetohydrodynamic angular velocity sensor to be calibrated is configured to output multiple angular velocity measurement data related to each angular vibration excitation.

[0033] The triaxial angular vibration turntable 110 can apply various angular vibration excitations to the workpiece 120 under test in three axes. These three axes include a first axis corresponding to the X-axis of the triaxial angular vibration turntable 110, a second axis corresponding to the Y-axis of the triaxial angular vibration turntable 110, and a third axis corresponding to the Z-axis of the triaxial angular vibration turntable 110. The triaxial angular vibration turntable 110 has three corresponding angular velocities in each of the three axes, namely, the first axial angular velocity... Second axial angular velocity and the third axial angular velocity Angular vibration excitation includes, but is not limited to, various types such as single-frequency sinusoidal angular vibration, frequency-sweep angular vibration, multi-frequency superposition angular vibration, or random angular vibration. By changing the vibration amplitude, frequency, and phase, the triaxial angular vibration turntable 110 can simulate dynamic angular motion environments of different intensities and bandwidths to meet the response testing requirements of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated under different working conditions.

[0034] The multi-channel probe array 130 is configured to emit multiple laser beams toward the fixture 120 under test and receive multiple reflected beams formed by the multiple laser beams reflected by the fixture 120 under test, thereby obtaining multiple linear velocity measurement data related to each type of angular vibration excitation.

[0035] A multi-channel probe array 130 is arranged around the fixture 120 under test. The multi-channel probe array 130 may contain multiple laser probes, each capable of independently emitting a laser beam directed at a specific reflection point on the surface of the fixture 120. When the fixture 120 undergoes a slight rotation under angular vibration excitation, the linear velocity of its surface reflection point changes. Multiple laser beams are reflected from the surface of the fixture to form multiple reflected beams, which are received by corresponding receivers in the probe array 130. By calculating the reflected beams, instantaneous linear velocity measurement data of each reflection point in the direction aligned with the beam direction can be obtained. These linear velocity data have a specific geometric relationship with the fixture's rotation radius and angular velocity, and therefore can be used to calibrate and verify a triaxial magnetohydrodynamic angular velocity sensor.

[0036] The processing module 140 is configured to obtain the calibration result of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated by using differential calibration and cross-coupling parameter identification based on multiple angular velocity measurement data and multiple linear velocity measurement data related to various angular vibration excitations.

[0037] Through embodiments of the present invention, a triaxial angular vibration turntable is used to apply multiple angular vibration excitations to the fixture under test, causing the triaxial magnetohydrodynamic angular velocity sensor to be calibrated, held by the fixture under test, to output multiple angular velocity measurement data related to each angular vibration excitation. Simultaneously, multiple laser beams are emitted to the fixture under test through a multi-channel probe array, and multiple reflected beams formed by the multiple laser beams reflected by the fixture under test are received, obtaining multiple linear velocity measurement data related to each angular vibration excitation. Thus, based on the multiple angular velocity measurement data and multiple linear velocity measurement data related to each of the multiple angular vibration excitations, the calibration result of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated can be obtained through differential calibration and cross-coupling parameter identification. This breaks through the geometric limitations of traditional single-axis calibration, enabling simultaneous measurement of triaxial angular velocity and triaxial translational velocity under triaxial synchronous angular vibration excitation, realistically simulating the actual working conditions of MHD-ARS, and obtaining more accurate cross-coupling parameters than the traditional axis-by-axis calibration method.

[0038] To achieve triaxial angular vibration calibration, a multi-channel probe array can include multiple vibration probes with different functions or in different layout positions. Specifically, the optical axes of each X-axis angular vibration differential measurement group are parallel to the Z-axis, and the line connecting the light spots formed by the multiple first vibration probes on the surface of the tested fixture is parallel to the Y-axis; the optical axes of each Y-axis angular vibration differential measurement group are parallel to the third axial direction, and the line connecting the light spots formed by the multiple second vibration probes on the surface of the tested fixture is parallel to the X-axis; the optical axes of each Z-axis angular vibration differential measurement group are parallel, and the line connecting the light spots formed by the multiple third vibration probes on the surface of the triaxial magnetohydrodynamic angular velocity sensor is parallel to the first axial direction; the vibration probes can be laser Doppler vibrometers (LDV), with all probes having parallel and coplanar optical axes, all pointing perpendicularly to the same measurement side of the tested fixture, and the working distance between the vibration probes and the tested fixture can be 60mm to 70mm. In one specific embodiment of the present invention, the multi-channel probe array may include multiple first vibration probes, multiple second vibration probes, and multiple third vibration probes.

[0039] The optical axis of each of the multiple first vibration probes is aligned with the third axis. The directions are parallel, and the line connecting the light spots formed by the multiple first vibration probes on the surface of the tested tool is parallel to the second axis. The orientations are parallel. The baseline spacing of the axes of the multiple first vibration probes is preferably 20 mm, and can be adjusted within the range of 15 mm to 25 mm according to the spot size and signal-to-noise ratio requirements. The mechanical and optical alignment error of the first vibration probe is controlled within ±0.005 mm.

[0040] The optical axis of each of the multiple second vibration probes is aligned with the third axis. The directions are parallel, and the line connecting the light spots formed by the multiple second vibration probes on the surface of the tested fixture is parallel to the first axis. The orientations are parallel. The baseline spacing of the axes of multiple second vibration probes can also be 20 mm, and can be adjusted within the range of 15 mm to 25 mm according to the spot size and signal-to-noise ratio requirements. At the same time, the second vibration probes must meet the requirements of no spot deviation under kilohertz-level high-frequency vibration, and the signal-to-noise ratio must be greater than or equal to 38 dB, with an alignment error less than or equal to ±0.005 mm.

[0041] The optical axes of the multiple third vibration probes are parallel, and the line connecting the light spots formed by the multiple third vibration probes on the surface of the triaxial magnetohydrodynamic angular velocity sensor is parallel to the first axis. The directions are parallel. The third vibration probe is used to pick up the third axial direction. The signals of translational motion, non-target axis crosstalk, high-frequency modal dynamic deformation of the structure, and unmodeled error terms are combined to assist in constructing a space vector overdetermined equation system to solve for the triaxial angular velocity components. Among them, the first axial direction Second axial direction and the third axis The directions are orthogonal to each other.

[0042] A multi-channel probe array emits multiple laser beams toward the fixture under test (DUT). Multiple optical targets are attached to the surface of the DUT, and the multiple light spots formed by the multi-channel probe array on the surface of the DUT are located within the effective reflection areas of the respective optical targets. The array also receives multiple reflected beams formed by the multiple laser beams reflected from the DUT.

[0043] In embodiments of the present invention, the optical target can be made based on microprism reflective tape with a reflectivity of not less than 98%. This microprism reflective tape is arranged in an array, preferably with a size of 8 mm × 8 mm, and adjustable within the range of 6 mm to 10 mm, and must completely cover the laser spot emitted by the multi-channel probe array. The geometric center of the microprism reflective tape strictly corresponds to the spot position of each vibration probe in the multi-channel probe array. For example, when the multi-channel probe array includes two first vibration probes, two second vibration probes, and two third vibration probes, the two first vibration probes correspond to one set of microprism reflective tape, the two second vibration probes correspond to another set of microprism reflective tape, and the two third vibration probes correspond to yet another set of microprism reflective tape. Furthermore, the center line connecting the pairs of tapes within each set is parallel to the baseline of the corresponding two vibration probes and remains absolutely parallel to the target vibration axis.

[0044] After introducing optical targets, in order to ensure that the laser spots of each vibration probe accurately fall within the effective reflection area of ​​the optical target, and to guarantee that each velocity measurement channel can obtain a stable and effective reflection signal, a camera module can be set in the angular vibration calibration device to monitor the laser spots in real time. In an embodiment of the present invention, the camera module is communicatively connected to the processing module and configured to acquire surface images of the workpiece under test; wherein, the processing module is further configured to determine the initial positions of multiple laser beams forming multiple spots on the surface of the workpiece under test based on the surface images, and adjust the pose of the multi-channel probe array and / or the pose of the three-axis angular vibration turntable based on the initial positions of the multiple spots and the effective reflection areas of the multiple optical targets, so that the multiple spots are respectively located within the effective reflection areas of the multiple optical targets.

[0045] By introducing a camera module, the focal length, incident angle, and installation direction of the multi-channel probe array can be finely adjusted based on the actual echo conditions, thereby improving the consistency and stability of multiple linear velocity measurement data.

[0046] During the process of a multi-channel probe array emitting multiple laser beams to the fixture under test and receiving multiple reflected beams formed by the laser beams reflected from the fixture, the laser beams and reflected beams may be affected by ambient stray light and airflow disturbances, resulting in inaccurate linear velocity measurement data. Therefore, an environmental control component can be set in the angular vibration calibration device. The environmental control component is set around the triaxial angular vibration turntable, and the multi-channel probe array is located inside the environmental control component. The environmental control component is configured to suppress ambient stray light and airflow disturbances, and can be combined with micro-environment flow field control (limiting the airflow velocity in the test area to ≤0.1m / s) to eliminate low-frequency phase drift caused by air refractive index disturbances within the optical path, further improving measurement stability.

[0047] Figure 2A schematic diagram of an angular vibration calibration device for a triaxial magnetohydrodynamic angular velocity sensor according to another embodiment of the present invention is shown.

[0048] like Figure 2 As shown, the angular vibration calibration device for the triaxial magnetohydrodynamic angular velocity sensor includes a triaxial angular vibration turntable 110, a test fixture 120, a multi-channel probe array 130, a processing module 140, an optical target 150, and an environmental control component 160. The specific functions and configuration relationships of each component in the angular vibration calibration device have been described in detail above and will not be repeated here.

[0049] Furthermore, before calibrating angular vibration using the angular vibration calibration device, a reference vibration source can be used to calibrate the measurement reference of the multi-channel probe array. In an embodiment of the present invention, the fixture under test is configured to hold the reference vibration source, and the reference vibration source is configured to output reference angular vibration excitation; wherein, the processing module is further configured to acquire multiple linear velocity data related to the reference angular vibration excitation from the multi-channel probe array, and use the multiple linear velocity data to calibrate the measurement reference of the multi-channel probe array.

[0050] The reference vibration source can be PCB 394C06. By applying a known vibration input, the sensitivity, amplitude consistency, and phase consistency of the multi-channel probe array are detected and corrected, so that the multi-channel output of the multi-channel probe array establishes a unified measurement reference relationship, thereby ensuring the comparability of subsequent linear velocity acquisition results and the accuracy of angular velocity calculation results, and establishing a unified measurement reference for triaxial MHD-ARS calibration.

[0051] In a specific embodiment of the present invention, the processing module can obtain the calibration result of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated based on the following processing flow: Utilizing the principle of rigid body kinematics, an overdetermined equation system is constructed based on multiple linear velocity measurement data and the illumination positions of multiple laser beams on the tested fixture; the overdetermined equation system is solved using the least squares method to obtain the first axial angular velocity component, the second axial angular velocity component, the third axial angular velocity component, the third axial translational component, and the coupling term error; inversion calculation is performed based on the coupling term error to obtain the first axial translational component and the second axial translational component; and a triaxial angular velocity reference value is obtained based on the first axial angular velocity component, the second axial angular velocity component, and the third axial angular velocity component, and based on the first axial translational component, the second axial translational component, and the third axial angular velocity reference value. The three-axis translational velocity reference value is obtained from the translational component; based on the three-axis angular velocity reference value, the three-axis translational velocity reference value, and multiple angular velocity measurement data related to angular vibration excitation, calibration samples related to angular vibration excitation are obtained; based on the multiple angular velocity measurement data of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated, and the correlation between the three-axis angular velocity reference value, the three-axis translational velocity reference value, and the fluid coupling term, a calibration model of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated is constructed, wherein the fluid coupling term includes the conductive fluid viscosity-Coriolis force flow field coupling function related to the three-axis angular velocity reference value and the three-axis translational velocity reference value; and based on multiple calibration samples, the calibration model is linearly fitted to obtain the angular-angular coupling matrix, the line-angular coupling matrix, and the fluid coupling coefficient matrix to obtain the calibration result.

[0052] Taking a multi-channel probe array comprising two first vibration probes, two second vibration probes, and two third vibration probes as an example, the multiple linear velocity measurement data output by the multi-channel probe array are as follows: , , , , , The corresponding triaxial magnetohydrodynamic angular velocity sensor outputs multiple angular velocity measurement data as follows: , , , , , The linear velocity measurement data serves as the initial input for the subsequent construction of the overdetermined equations and the solution of the angular velocity, and is used to characterize the motion state of the measured object at each measurement point.

[0053] Subsequently, based on the spatial relationship of the six measuring points and the principles of rigid body kinematics, an overdetermined system of equations consisting of six channels of linear velocity measurement data was constructed. This system was then solved using the least squares method to obtain reference estimates of the triaxial angular velocities of the measured fixture. Specifically, this includes the following:

[0054] First, the measurement relationship of rigid body kinematics is established. For the linear velocity measurement data acquired by the i-th LDV channel, based on the principle of rigid body kinematics, the measurement relationship can be expressed as:

[0055] (1).

[0056] in, The linear velocity measurement data is obtained for the i-th LDV. Let be the unit vector of the measurement direction of the i-th LDV. Let be the translational velocity vector of the tooling under test. For triaxial angular velocity, Let be the position vector of the irradiation position of the i-th LDV relative to the rotation center. This includes noise and unmodeled errors.

[0057] Second, differential equation construction. To eliminate translational common-mode interference, a differential structure is used to combine the corresponding linear velocity measurement data. The linear velocity measurement data of the two first vibration probes are as follows: , The linear velocity measurement data of the two second vibration probes are as follows: , The linear velocity measurement data of the two third vibration probes are as follows: , At this point, by differentially processing the linear velocity measurement data of the two first vibration probes and the linear velocity measurement data of the two second vibration probes, we can obtain:

[0058] (2).

[0059] (3).

[0060] in, The baseline length between the two first vibration probes. The baseline length between the two second vibration probes.

[0061] Two third vibration probes are used to assist in decoupling monitoring. The linear velocity measurement data of the two third vibration probes can be expressed as follows:

[0062] (4).

[0063] in, These are the position coordinates of the illumination spots of the two third vibration probes in the tooling coordinate system. This includes the combined term of high-frequency modal dynamic deformation and unmodeled error, as well as the unmodeled error term. The translational velocity vector along the third axis is given by the above relationship, which is used to reflect the influence of translational motion along the third axis, coupling with non-target axes, and structural deformation on the measurement results.

[0064] Third, the overdetermined equations are expressed in a unified manner. Based on the six-channel linear velocity measurement data, the measurement relationships can be uniformly written in matrix form:

[0065] (5).

[0066] (6).

[0067] in, This represents the linear velocity measurement data from six channels, and X represents the parameter vector to be solved. The mapping matrix is ​​determined by the spatial positional relationship of the multi-channel probe array. To measure noise and unmodeled error terms, This is a comprehensive term representing structural deformation. Since there are 6 equations and 5 unknown parameters, this constitutes an overdetermined system of equations.

[0068] Fourth, decoupling and solving. The above overdetermined equations are solved using the least squares method to obtain the optimal estimates of the parameters to be estimated:

[0069] (7).

[0070] Thus, the triaxial angular velocity components of the triaxial magnetohydrodynamic angular velocity sensor are obtained, and the reference values ​​of the triaxial angular velocity are obtained by laser differential calculation. This solution process can utilize multi-channel redundant observation information to effectively preserve the angular velocity of the measured axis and suppress crosstalk, translational interference, and structural errors of non-target axes, thereby improving the accuracy and stability of angular velocity measurement and calibration.

[0071] Triaxial angular velocity reference values ​​were obtained through laser differential calculation. Translational velocity parameters of the three-axis model Then, the above velocity values ​​can be further solved to obtain the cross-coupling parameters.

[0072] By incorporating the fluid coupling term unique to MHD-ARS, a calibration model for the triaxial magnetohydrodynamic angular velocity sensor can be obtained:

[0073] (8).

[0074] in, This is a fluid coupling coefficient matrix unique to MHD-ARS (other inertial sensors do not have fluid characteristics and therefore do not have this item). The viscosity of the conductive fluid is characterized by the Coriolis force-flow field coupling function, and η is the fluid viscosity coefficient of MHD-ARS. It is a 3×3 angle-to-angle coupling matrix. The diagonal elements represent the principal axis sensitivities of each axis. The off-diagonal elements are the inter-axis cross-coupling coefficients. This is a 3×3 line-angle coupling matrix, representing the effect of linear vibration on the angular velocity output. It is a zero-bias vector. For measuring noise.

[0075] Through multiple sets of excitation experiments with different directions and frequencies (including single-axis excitation, dual-axis synchronous excitation, and tri-axis synchronous excitation), sufficient input-output data pairs were obtained. The least squares method was used to solve the equations corresponding to the calibration model of the above-mentioned triaxial magnetohydrodynamic angular velocity sensor, resulting in a complete... and The matrix enables accurate identification of the cross-coupling parameters of the three-axis MHD-ARS. In embodiments of this invention, a regularized least squares method for fluid coupling constraints can be used to solve the problem, with the constraints set based on the fluid physics characteristics of the MHD-ARS. The corner-to-corner coupling matrix, line-to-corner coupling matrix, principal axis sensitivity, zero bias, and cross-coupling error compensation model of the three-axis MHD-ARS are output for subsequent error compensation.

[0076] In the embodiments of this invention, synchronous decoupling of triaxial angular vibration is achieved by improving the physical model. This enables the technical solution of this invention to distinguish between rotational and translational components, solves the phase aliasing problem, and achieves independent and accurate identification of the triaxial MHD-ARS angular-angular coupling matrix and line-angular coupling matrix. Moreover, it avoids target miss or loss of lock during the high-frequency broadband calibration required for MHD-ARS processing, and maintains a high signal-to-noise ratio and signal integrity even under high-frequency response conditions. Furthermore, by setting the baseline spacing of the multi-channel probe array, it ensures no spot miss under high-frequency vibration and maintains a measurement signal-to-noise ratio greater than or equal to 38 dB, enabling high-precision cross-coupling calibration within the wide bandwidth of triaxial MHD-ARS. Simultaneously, based on the integrated single-sided optical path design, visual alignment method, and automated triaxial MHD-ARS cross-coupling parameter identification algorithm, a complete error compensation matrix can be output at once, eliminating the need for manual measurement and calculation axis by axis. This reduces the test preparation cycle from the traditional 8 hours to 2 hours, improving calibration efficiency by more than 4 times.

[0077] Figure 3 A flowchart illustrating an angular vibration calibration method for a triaxial magnetohydrodynamic angular velocity sensor according to an embodiment of the present invention is shown.

[0078] like Figure 3As shown, the angular vibration calibration method for a triaxial magnetohydrodynamic angular velocity sensor is applied to the aforementioned angular vibration calibration device for a triaxial magnetohydrodynamic angular velocity sensor, including operations S310~S320.

[0079] During the operation of S310, while controlling the triaxial angular vibration turntable to apply various angular vibration excitations to the fixture under test, multiple angular velocity measurement data related to each angular vibration excitation are obtained from the output of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated, and multiple linear velocity measurement data related to each angular vibration excitation are obtained from the output of the multi-channel probe array.

[0080] In operation of S320, based on multiple angular velocity measurement data and multiple linear velocity measurement data related to various angular vibration excitations, the calibration results of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated are obtained through differential calibration and cross-coupling parameter identification.

[0081] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0082] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. An angular vibration calibration device for a triaxial magnetohydrodynamic angular velocity sensor, characterized in that, The device includes a triaxial angular vibration turntable, a test fixture, a multi-channel probe array, and a processing module. The test fixture is fixedly mounted on the triaxial angular vibration turntable and is configured to hold a triaxial magnetohydrodynamic angular velocity sensor to be calibrated. The processing module is communicatively connected to both the triaxial magnetohydrodynamic angular velocity sensor to be calibrated and the multi-channel probe array. The triaxial angular vibration turntable is configured to apply various angular vibration excitations to the tooling under test; The triaxial magnetohydrodynamic angular velocity sensor to be calibrated is configured to output multiple angular velocity measurement data related to each type of angular vibration excitation; The multi-channel probe array includes multiple first vibration probes, multiple second vibration probes, and multiple third vibration probes; In this configuration, the optical axis of each of the plurality of first vibration probes is parallel to the third axial direction, and the line connecting the light spots formed by each of the plurality of first vibration probes on the surface of the workpiece under test is parallel to the second axial direction. The optical axis of each of the plurality of second vibration probes is parallel to the third axial direction, and the line connecting the light spots formed by each of the plurality of second vibration probes on the surface of the test fixture is parallel to the first axial direction. The optical axes of the plurality of third vibration probes are parallel, and the line connecting the light spots formed by the plurality of third vibration probes on the surface of the triaxial magnetohydrodynamic angular velocity sensor is parallel to the first axial direction. The first axial direction, the second axial direction, and the third axial direction are each orthogonal; The multi-channel probe array is configured to emit multiple laser beams toward the test fixture and receive multiple reflected beams formed by the multiple laser beams reflected by the test fixture, thereby obtaining multiple linear velocity measurement data related to each type of angular vibration excitation; The processing module is configured as follows: Using the principles of rigid body kinematics, and based on multiple linear velocity measurement data and the illumination positions of multiple laser beams on the tested fixture, an overdetermined set of equations is constructed. The overdetermined equations are solved using the least squares method to obtain the first axial angular velocity component, the second axial angular velocity component, the third axial angular velocity component, the third axial translational component, and the coupling term error. Inversion calculations are performed based on the coupling term error to obtain the first axial translational component and the second axial translational component; Based on the first axial angular velocity component, the second axial angular velocity component, and the third axial angular velocity component, a triaxial angular velocity reference value is obtained, and based on the first axial translational component, the second axial translational component, and the third axial translational component, a triaxial translational velocity reference value is obtained; Based on the triaxial angular velocity reference values, triaxial translational velocity reference values, and multiple angular velocity measurement data related to angular vibration excitation, calibration samples related to angular vibration excitation are obtained; Based on multiple angular velocity measurement data of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated, and the correlation between these data and the triaxial angular velocity reference values, the triaxial translational velocity reference values, and the fluid coupling term, a calibration model for the triaxial magnetohydrodynamic angular velocity sensor to be calibrated is constructed. The fluid coupling term includes a conductive fluid viscosity-Coriolis force flow field coupling function related to the triaxial angular velocity reference values ​​and the triaxial translational velocity reference values. Based on multiple calibration samples, the calibration model is linearly fitted to obtain the corner-corner coupling matrix, the line-corner coupling matrix, and the fluid coupling coefficient matrix to obtain the calibration results.

2. The angular vibration calibration device according to claim 1, characterized in that, The surface of the test fixture is attached with multiple optical targets, and the multiple light spots formed by the multi-channel probe array on the surface of the test fixture are respectively located within the effective reflection areas of the multiple optical targets.

3. The angular vibration calibration device according to claim 2, characterized in that, The angular vibration calibration device further includes: A camera module, which is communicatively connected to the processing module, is configured to acquire surface images of the tooling under test. The processing module is further configured to determine the initial positions of multiple light spots formed by the multiple laser beams on the surface of the test fixture based on the surface image, and adjust the pose of the multi-channel probe array and / or the pose of the triaxial angular vibration turntable based on the initial positions of the multiple light spots and the effective reflection areas of the multiple optical targets, so that the multiple light spots are respectively located within the effective reflection areas of the multiple optical targets.

4. The angular vibration calibration device according to claim 1, characterized in that, The fixture under test is configured to hold a reference vibration source, and the reference vibration source is configured to output a reference angular vibration excitation. The processing module is further configured to acquire multiple linear velocity data related to the reference angular vibration excitation from the multi-channel probe array, and to use the multiple linear velocity data to calibrate the measurement reference of the multi-channel probe array.

5. The angular vibration calibration device according to claim 1, characterized in that, The angular vibration calibration device further includes: An environmental control component is arranged around the triaxial angular vibration turntable, and the multi-channel probe array is located inside the environmental control component. The environmental control component is configured to suppress ambient stray light and airflow disturbances.

6. A method for angular vibration calibration of a triaxial magnetohydrodynamic angular velocity sensor, applied to the angular vibration calibration device as described in any one of claims 1 to 5, characterized in that, The angular vibration calibration method includes: During the process of controlling the triaxial angular vibration turntable to apply various angular vibration excitations to the tooling under test, multiple angular velocity measurement data related to each angular vibration excitation are obtained from the output of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated, and multiple linear velocity measurement data related to each angular vibration excitation are obtained from the output of the multi-channel probe array. Based on multiple angular velocity measurement data and multiple linear velocity measurement data related to various angular vibration excitations, the calibration results of the triaxial magnetohydrodynamic angular velocity sensor to be calibrated are obtained through differential calibration and cross-coupling parameter identification.

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