Angular vibration sensor based on magnetohydrodynamics

Abstract

The present invention provides an angular vibration sensor based on magnetohydrodynamics. The angular vibration sensor includes: a housing with a cavity formed inside; a magnetic yoke installed in the cavity; a plurality of permanent magnets stacked and installed in the cavity in the height direction and located below the magnetic yoke; a plurality of sensitive components stacked in the height direction between two adjacent permanent magnets. Each sensitive component includes: an annular cavity containing a conductive fluid; wherein, the plurality of annular cavities are connected in series electrically. The conductive fluid in each annular cavity rotates around the sensitive axis based on the input of an external angular vibration in the environment of the magnetic field provided by the plurality of permanent magnets. By utilizing the inertia of the conductive fluid in each sensitive component relative to the annular cavity containing the conductive fluid, relative motion of the conductive fluid relative to the annular cavity is generated, and then the magnetic induction lines are cut to generate an induced electromotive force, thereby realizing the measurement of angular vibration.

Description

Technical Field

[0001] At least one embodiment of the present invention relates to the technical field of inertial sensors, and particularly to a micro angular vibration sensor based on magnetohydrodynamics. Background Art

[0002] Magnetohydrodynamic (MHD) micro angular vibration sensors designed based on the principle of magnetohydrodynamics play a crucial role in many fields with high-precision requirements such as aerospace, precision engineering, seismic monitoring, and biomedicine. Magnetohydrodynamic micro angular vibration sensors sense minute angular vibrations by detecting the movement of a fluid in a magnetic field. Their non-contact measurement method and high sensitivity to minute vibrations make them an indispensable tool in these fields.

[0003] However, with the continuous progress of technology, the accuracy requirements for micro angular vibration detection in the field of test and measurement are also constantly increasing, posing challenges to the measurement accuracy of traditional magnetohydrodynamic micro angular vibration sensors. The performance of magnetohydrodynamic micro angular vibration sensors is gradually becoming difficult to meet the increasingly demanding accuracy standards. Summary of the Invention

[0004] In view of this, the present invention provides an angular vibration sensor based on magnetohydrodynamics, which can improve the measurement accuracy.

[0005] As an aspect of an embodiment of the present invention, there is provided an angular vibration sensor based on magnetohydrodynamics, including a housing, a magnetic yoke, a plurality of permanent magnets, and a plurality of sensitive components. A cavity is formed inside the housing, and the magnetic yoke is installed in the cavity; the plurality of permanent magnets are stacked and installed in the cavity in the height direction and are located below the magnetic yoke. The plurality of sensitive components are stacked in the height direction between two adjacent permanent magnets, and each sensitive component includes: an annular cavity containing a conductive fluid. Among them, the plurality of annular cavities are connected in series electrically. In the environment of the magnetic field provided by the plurality of permanent magnets, based on the input of an external angular vibration, each annular cavity rotates around a sensitive axis. By using the inertia of the conductive fluid in each sensitive component relative to the annular cavity containing the conductive fluid, relative movement of the conductive fluid relative to the annular cavity is generated, thereby cutting magnetic induction lines to generate an induced electromotive force and realizing the measurement of the angular vibration.

[0006] According to an embodiment of the present invention, each annular cavity includes an inner electrode, two opposed cover bodies, and an annular outer electrode. The two opposed cover bodies radially extend outward at the upper and lower ends of the inner electrode respectively, and the annular outer electrode is installed between the two cover bodies and encloses a closed annular space with the inner electrode and the two cover bodies, restricting the conductive fluid in the annular space.

[0007] According to an embodiment of the present invention, the angular vibration sensor further includes a plurality of series electrodes located between two adjacent ones of the above-mentioned annular cavities, adapted to connect in series the inner electrode of one of the two adjacent annular cavities and the outer electrode of the other annular cavity.

[0008] According to an embodiment of the present invention, each of the above-mentioned series electrodes includes a first electrode and a second electrode. The permanent magnet between two adjacent annular cavities is located on the first electrode. The first electrode is electrically connected to the outer electrode of one of the two adjacent annular cavities. The first electrode is adjacent to one of the covers of the other annular cavity through an insulating gasket. The second electrode extends from the inner electrode of the other of the two annular cavities, passes through the insulating gasket to the first electrode, and cooperates with the first electrode to connect in series the inner electrode of one of the two adjacent annular cavities and the outer electrode of the other annular cavity.

[0009] According to an embodiment of the present invention, the average magnetic induction intensities of the above-mentioned plurality of sensitive components are consistent.

[0010] According to an embodiment of the present invention, the distances between two adjacent ones of the above-mentioned permanent magnets are equal, and the first distance between the magnetic yoke and the first permanent magnet of the first sensitive component close to the magnetic yoke is equal to the second distance between the bottom wall of the above-mentioned cavity and the second permanent magnet close to the bottom wall.

[0011] According to an embodiment of the present invention, an adjusting member made of an insulating material is provided between the first permanent magnet and the first sensitive component close to the first permanent magnet to limit the distance between the first permanent magnet and the permanent magnet adjacent to the first permanent magnet through the adjusting member.

[0012] According to an embodiment of the present invention, a guiding groove is provided on the adjusting member, and an external wire passes through the guiding groove and is electrically connected to the first sensitive component to lead out the induced electromotive force through the wire.

[0013] According to an embodiment of the present invention, the housing includes a base, a sleeve, and an end cap. The sleeve is installed on the base. A flange extending radially inward is formed at the upper part of the sleeve, and the magnetic yoke is installed on the flange. The end cap is installed on the top of the sleeve to cooperate with the base to enclose the cavity surrounded by the sleeve.

[0014] According to an embodiment of the present invention, the angular vibration sensor further includes a signal amplification circuit installed on the end cap, adapted to amplify the induced electromotive forces generated by the above-mentioned plurality of sensitive components.

[0015] According to the angular vibration sensor based on magnetohydrodynamics of the embodiment of the present invention, by connecting multiple annular cavities in series electrically, without changing the radial size of the angular vibration sensor, it is equivalent to increasing the equivalent radius of the conductive fluid. The measured induced electromotive force is the sum of the induced electromotive forces of multiple channels. The series connection of multiple sensitive components can effectively suppress noise, making the signal-to-noise ratio of the output signal of the angular vibration sensor higher, thereby achieving higher-precision detection. It can achieve measurements as low as ±0.005 rad / s, and has the advantages of strong scalability, high reliability, and wide bandwidth, providing strong support for future high-precision earth observation, optical payload platforms, and line-of-sight stabilization and suppression. Description of the Drawings

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

[0017] Figure 1 Schematically shows a cross-sectional view of an angular vibration sensor based on magnetohydrodynamics according to an embodiment of the present invention;

[0018] Figure 2 Schematically shows Figure 1 A partially enlarged view of the angular vibration sensor shown;

[0019] Figure 3 Shows a circuit diagram of a signal amplification circuit according to an embodiment of the present invention;

[0020] Figure 4 Shows a calibration test curve graph of an angular vibration sensor according to an embodiment of the present invention;

[0021] Figure 5 Shows a phase test curve graph of an angular vibration sensor according to an embodiment of the present invention;

[0022] Figure 6 Shows a noise test curve graph of an angular vibration sensor according to an embodiment of the present invention.

[0023] The description of the reference numerals is as follows:

[0024] 1 - Housing;

[0025] 11 - Base;

[0026] 12 - Sleeve;

[0027] 13 - End Cap;

[0028] 2 - Yoke;

[0029] 3 - Permanent Magnet;

[0030] 4 - Sensitive Component;

[0031] 41 - Conductive fluid;

[0032] 42 - Annular cavity;

[0033] 421 - Inner electrode;

[0034] 4211 - Threaded hole;

[0035] 422 - Cover body;

[0036] 423 - Outer electrode;

[0037] 5 - Series electrode;

[0038] 51 - First electrode;

[0039] 52 - Second electrode;

[0040] 6 - Insulating gasket;

[0041] 7 - Adjusting part;

[0042] 71 - Guide groove;

[0043] 8 - Signal amplification circuit;

[0044] 81 - First - stage amplification unit;

[0045] 82 - Second - stage amplification unit;

[0046] 83 - Coupling unit;

[0047] 9 - Screw;

[0048] 10 - Insulating part. Detailed implementation manners

[0049] To make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0050] The terms used herein are merely for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising" and the like used herein indicate the presence of the 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.

[0051] 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 should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0052] In the case of using expressions such as "at least one of A, B, and C", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C. In the case of using expressions such as "at least one of A, B, or C", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0053] It should also be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only references to the directions in the drawings and are not used to limit the protection scope of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion in the understanding of the present invention, conventional structures or configurations will be omitted.

[0054] In the process of implementing the present invention, it is found that in practical applications, higher and higher requirements are put forward for micro-angular vibration measurement. Conventional sensors based on miniaturization design are difficult to meet the existing requirements, and there is an urgent need for micro-angular vibration measurement with an extremely small range below 0.01 rad / s. At the same time, it is necessary to avoid the effective signal being submerged in noise, and strict technical specifications are put forward for the noise of the sensor itself.

[0055] The scale calculation formula of the micro-angular vibration sensor based on magnetohydrodynamics in the passband is:

[0056] (1);

[0057] Where, is the output electromotive force; is the input angular velocity; is the average magnetic induction intensity of the fluid region; is the width of the conductive fluid ring; is the equivalent radius of the conductive fluid; is the outer diameter of the conductive fluid; is the inner diameter of the conductive fluid.

[0058] It can be seen from formula (1) that in a micro-angular vibration sensor with an axial magnetic field, increasing the scale factor or increasing the equivalent radius of the conductive fluid ring can increase the magnitude of the output electromotive force

[0059] In practical applications, due to the limitations of the miniaturized application scenarios of the micro angular vibration sensor based on magnetohydrodynamics, the radial width cannot be increased blindly.

[0060] Figure 1 Schematically shows a cross-sectional view of an angular vibration sensor based on magnetohydrodynamics according to an embodiment of the present invention. Figure 2 Schematically shows Figure 1 A partially enlarged view of the angular vibration sensor shown.

[0061] As an aspect of an embodiment of the present invention, an angular vibration sensor based on magnetohydrodynamics (or called a micro angular vibration sensor) is provided. As shown in Figure 1 and Figure 2 The angular vibration sensor includes a housing 1, a yoke 2, a plurality of permanent magnets 3, and a plurality of sensitive components 4. A cavity is formed inside the housing 1, and the yoke 2 is installed in the cavity. The plurality of permanent magnets 3 are stacked and installed in the cavity in the height direction and are located below the yoke 2. The plurality of sensitive components 4 are stacked in the height direction between two adjacent permanent magnets 3. Each sensitive component 4 includes an annular cavity 42 with an internally provided conductive fluid 41. Among them, the plurality of annular cavities 42 are connected in series electrically. The conductive fluid 41 in each annular cavity 42 rotates around the sensitive axis based on the input of an external angular vibration in the environment of the magnetic field provided by the plurality of permanent magnets 3. Using the inertia of the conductive fluid 41 in each sensitive component 4 relative to the annular cavity 42 containing the conductive fluid 41, the conductive fluid 41 generates relative motion relative to the annular cavity 42, and then cuts the magnetic induction line to generate an induced electromotive force, realizing the measurement of angular vibration.

[0062] For the angular vibration sensor based on magnetohydrodynamics according to an embodiment of the present invention, by connecting the plurality of annular cavities 42 in series electrically, without changing the radial size of the angular vibration sensor, it is equivalent to increasing the equivalent radius of the conductive fluid 41. The measured induced electromotive force is the sum of the induced electromotive forces of multiple channels. The series connection of the plurality of sensitive components 4 can effectively suppress noise, making the signal-to-noise ratio of the output signal of the angular vibration sensor higher, so as to achieve higher-precision detection. It can realize micro angular vibration measurement as low as ±0.005 rad / s, and has the advantages of strong expandability, high reliability, and wide bandwidth, providing strong support for future high-precision earth observation, optical payload platforms, and line-of-sight stabilization and suppression.

[0063] According to an embodiment of the present invention, the conductive fluid 41 can be a liquid metal, for example, a liquid gallium-based metal with high conductivity.

[0064] In a schematic embodiment, the low-frequency cut-off frequency of each of the plurality of sensitive components 4 is lower than 2 Hz. The overall low-frequency cut-off frequency of the plurality of sensitive components 4 connected in series is lower than 2 Hz. In this way, the micro angular vibration sensor can measure angular vibration signals at lower frequencies, expanding the measurement range of the micro angular vibration sensor and making it applicable to a wider range of scenarios.

[0065] According to an embodiment of the present invention, the relationship between the number m of permanent magnets 3 and the number n of sensitive components 4 is m = n + 1.

[0066] In a schematic embodiment, the number n of sensitive components 4 may include any one of 2, 3, 4, 5, 6, etc.

[0067] In a schematic embodiment, the cross-section of the permanent magnet 3 in the horizontal plane is circular, and the magnetization direction of the permanent magnet 3 is axial magnetization, which is used to generate a constant magnetic field required by the micro angular vibration sensor.

[0068] According to an embodiment of the present invention, the plurality of permanent magnets 3 are arranged at equal intervals. The two adjacent permanent magnets 3 provide a constant axial magnetic field for the sensitive component 4 located between the two permanent magnets 3. When the plurality of sensitive components 4 rotate around the sensitive axis, the plurality of sensitive components 4 respectively generate corresponding induced electromotive forces.

[0069] According to an embodiment of the present invention, as Figure 1 shown, the housing 1 includes a base 11, a sleeve 12, and an end cap 13. The sleeve 12 is installed on the base 11. An annular flange is formed by the upper part of the sleeve 12 extending radially inward, and the magnetic yoke 2 is installed on the flange. The end cap 13 is installed on the top of the sleeve 12 to cooperate with the base 11 to enclose the cavity formed by the sleeve 12.

[0070] According to an embodiment of the present invention, the space between the magnetic yoke 2 and the base 11 is the external magnetic conduction circuit of the micro angular vibration sensor.

[0071] In a schematic embodiment, the base 11 and the sleeve 12 can be made of high-permeability materials. It can form a complete magnetic conduction circuit with the magnetic yoke 2, improve the intensity and uniformity of the magnetic field, and can effectively isolate external magnetic field interference, ensuring the stability and consistency of the magnetic field, thereby improving the measurement accuracy of the micro angular vibration sensor.

[0072] According to an embodiment of the present invention, the components located inside the cavity need to be rigidly fixed together.

[0073] According to an embodiment of the present invention, as Figure 1As shown, each annular cavity 42 includes an inner electrode 421, two opposing cover bodies 422, and an annular outer electrode 423. The two opposing cover bodies 422 radially extend outwardly at the upper and lower ends of the inner electrode 421 respectively. The annular outer electrode 423 is installed between the two cover bodies 422, and together with the inner electrode 421 and the two cover bodies 422, it encloses a closed annular space, confining the conductive fluid 41 within the annular space.

[0074] According to an embodiment of the present invention, the two cover bodies 422 are made of a high-permeability material, for example, a high-permeability soft magnetic alloy material.

[0075] In a schematic embodiment, both the inner electrode 421 and the outer electrode 423 are made of oxygen-free copper.

[0076] In a schematic embodiment, the inner electrode 421 includes a main body portion and two extending portions that radially extend outwardly along the main body portion. The two extending portions are located at the upper and lower ends of the main body portion, and the diameters of the two extending portions are smaller than the diameter of the main body portion. The two cover bodies 422 are annular. The two extending portions respectively pass through the middle holes of the two annular cover bodies 422, and the inner edges of the two annular cover bodies 422 are respectively abutted against the upper and lower ends of the main body portion.

[0077] The outer electrode 423 is annular, and a convex portion extends radially inwardly in the middle of the outer electrode 423. The outer edges of the two annular cover bodies 422 are respectively abutted against the upper and lower surfaces of the convex portion, closing the annular space.

[0078] In a schematic embodiment, the inner electrode 421 and the two cover bodies 422 are bonded together by a colloid.

[0079] In a schematic embodiment, the outer electrode 423 and the two cover bodies 422 are bonded together by a colloid.

[0080] According to an embodiment of the present invention, as Figure 1 and Figure 2 shown, the micro angular vibration sensor further includes a plurality of series electrodes 5. The plurality of series electrodes 5 are located between two adjacent annular cavities 42, and are adapted to connect in series the inner electrode 421 of one annular cavity 42 and the outer electrode 423 of another adjacent annular cavity 42.

[0081] For the micro angular vibration sensor based on magnetohydrodynamics according to an embodiment of the present invention, by connecting in series the inner electrode 421 of one annular cavity 42 and the outer electrode 423 of another adjacent annular cavity 42 through a plurality of series electrodes 5, the series connection of a plurality of sensitive components 4 is realized, increasing the radial sensitive width of the conductive fluid 41 of the micro angular vibration sensor, effectively amplifying the weak induced electromotive force signal, and enabling high-precision detection as low as ±0.005 rad / s.

[0082] According to an embodiment of the present invention, as Figure 1 shown, a first gap is formed between the outer edge of the series electrode 5 and the inner wall of the sleeve 12, and a second gap communicating with the first gap is formed between the outer edge of the outer electrode 423 and the inner wall of the sleeve 12. When testing a single sensitive component 4, an external wire can extend into the space formed by the plurality of first gaps and the second gap to respectively lead out the induced electromotive force signals generated by each sensitive component 4.

[0083] According to an embodiment of the present invention, as Figure 1 shown, each series electrode 5 includes a first electrode 51 and a second electrode 52. The permanent magnet 3 between two adjacent annular cavities 42 is located on the first electrode. The first electrode 51 is electrically connected to the outer electrode 423 of one of the two adjacent annular cavities 42 through a screw 9, and the first electrode 51 is adjacent to one of the cover bodies 422 of the other annular cavity 42 through an insulating gasket 6. The second electrode 52 extends from the inner electrode 421 of the other of the two annular cavities 42, passes through the insulating gasket 6 and extends to the first electrode 51, and cooperates with the first electrode 51 to connect the inner electrode 421 of one of the two adjacent annular cavities 42 in series with the outer electrode 423 of the other annular cavity 42.

[0084] In such an embodiment, by providing the insulating gasket 6, the electrodes between adjacent annular cavities 42 can be effectively isolated.

[0085] According to an embodiment of the present invention, as Figure 1 and Figure 2 shown, the angular vibration sensor further includes an insulating member 10. The insulating member 10 is recessed downward to form a groove, and the permanent magnet 3 is located in the groove. The permanent magnet 3 is mounted on the first electrode 51 through the insulating member 10.

[0086] In a schematic embodiment, the first electrode 51 is connected to the outer electrode 423 through a screw 9 (which can be a flat head screw, for example). Further, a threaded hole matching the external thread of the screw 9 is formed on the outer electrode 423. The screw 9 passes through the edge of the first electrode 51 and the groove wall of the insulating member 10 in sequence and is combined into the threaded hole on the outer electrode 423 to fix the first electrode 51, the outer electrode 423 and the insulating member 10, and ensure the reliability of the electrical connection between the first electrode 51 and the outer electrode 423.

[0087] In a schematic embodiment, the second electrode 52 can be a screw (which can be a flat head screw, for example). The second electrode 52 passes through the insulating gasket 6 from the inner electrode 421 and is threadedly combined to the second electrode 52 to realize the fixation between the inner electrode 421 and the second electrode 52, and ensure the reliability of the electrical connection between the inner electrode 421 and the outer electrode 423.

[0088] According to an embodiment of the present invention, the average magnetic induction intensity of multiple sensitive components 4 is consistent.

[0089] According to an embodiment of the present invention, the consistency of the average magnetic induction intensity of multiple sensitive components 4 can ensure that the signal intensities of the induced electromotive forces output by each sensitive component 4 are approximately the same, avoiding errors caused by differences in magnetic induction intensity and improving the reliability of the measurement results.

[0090] According to an embodiment of the present invention, as Figure 1 and Figure 2 shown, the distances between adjacent two permanent magnets 3 are equal, and the first distance t1 between the yoke 2 and the first permanent magnet of the first sensitive component 4 close to the yoke 2 is equal to the second distance t2 between the bottom wall of the cavity and the second permanent magnet close to the bottom wall, that is, t1 = t2.

[0091] In such an embodiment, it can be ensured that each sensitive component 4 is under a substantially consistent magnetic field intensity, avoiding the influence of the magnetic field gradient on the output signal of the angular vibration sensor, thereby improving the measurement accuracy.

[0092] According to an embodiment of the present invention, an adjusting member 7 made of an insulating material is provided between the first permanent magnet and the first sensitive component close to the first permanent magnet to limit the distance between the first permanent magnet and the permanent magnet adjacent to the first permanent magnet through the adjusting member 7.

[0093] According to an embodiment of the present invention, a guiding groove 71 is formed on the adjusting member 7, and an external wire passes through the guiding groove 71 and is electrically connected to the first sensitive component 4 to lead out the induced electromotive force through the wire.

[0094] As Figure 1 and Figure 2 shown, a threaded hole 4211 is formed on the first inner electrode of the first sensitive component, and an external screw is threadedly engaged with the threaded hole 4211 to connect the wire passing through the guiding groove 71 to the inner electrode 421.

[0095] Figure 3 Shows the circuit diagram of the signal amplification circuit according to an embodiment of the present invention.

[0096] According to an embodiment of the present invention, as Figure 1 and Figure 3 shown, the angular vibration sensor further includes a signal amplification circuit 8, and the signal amplification circuit 8 is installed on the end cover 13 and is suitable for amplifying the induced electromotive forces generated by multiple sensitive components.

[0097] According to an embodiment of the present disclosure, the signal amplification circuit 8 is a low-noise amplification circuit, and the noise level is (output voltage noise density).

[0098] According to an embodiment of the present invention, as Figure 3 shown, the signal amplification circuit 8 includes a first-stage amplification unit 81, a second-stage amplification unit 82, and a coupling unit 83. The signal amplification circuit 8 should reduce the noise figure of the first-stage amplification unit 81, while the gain of the first-stage amplification unit 81 is much greater than the gain of the second-stage amplification unit 82.

[0099] As Figure 3 shown, In+ and In- represent the signal input terminals.

[0100] When the angular vibration sensor provided by the present invention is in normal use, In+ is connected to one of the first wire connected to the first inner electrode of the first sensitive component and the second wire connected to the second outer electrode of the second sensitive component near the base, and In- is connected to the other of the first wire and the second wire.

[0101] When testing a single sensitive component 4 of the angular vibration sensor provided by the present invention, In+ is connected to one of the inner electrode 421 and the outer electrode 423 of the sensitive component 4 to be tested, and In- is connected to the other of the inner electrode 421 and the outer electrode 423 of the sensitive component 4 to be tested.

[0102] As Figure 3 shown, the first-stage amplification unit 81 includes an amplifier A1. The second-stage amplification unit 82 includes an amplifier A3, a resistor R2, and a resistor R3. The first input terminal of the amplifier A3 is connected to the output terminal of the amplifier A1 for receiving the output signal Vout1 of the amplifier A1. The second input terminal of the amplifier A3 is grounded (GND) through the resistor R2, the second input terminal of the amplifier A3 is connected to the output terminal of the amplifier A3 through the resistor R3, the output terminal of the amplifier A3 is connected to the other end of the resistor R1, and an amplified signal Vout2 is output.

[0103] The coupling unit 83 includes an amplifier A2, a resistor R1, and a capacitor C. The first input terminal of the amplifier A2 is connected to one end of the resistor R1, the first input terminal is connected to one end of the capacitor C, the other end of the capacitor C is connected to the output terminal of the amplifier A2, the output signal of the amplifier A2 is fed back to the amplifier A1 as a reference signal (Ref), and the second input terminal of the amplifier A2 is grounded (GND).

[0104] According to an embodiment of the present invention, since the induced electromotive force signal sensed by the micro angular vibration sensor based on magnetic fluid is extremely weak, very high requirements are imposed on the noise performance of the micro angular vibration sensor itself.

[0105] The noise equivalent angular rate and the noise equivalent angular position are important indicators for evaluating the magnetic fluid micro angular vibration sensor, and their definitions are as follows:

[0106] Sampled voltage waveform The power spectral density is:

[0107] (2);

[0108] wherein, is the average number of segments, is the data point number, is the number of data, is the input angular vibration frequency, is the imaginary unit, is the base of the natural logarithm.

[0109] The power spectral density of the noise equivalent angular rate of the micro angular vibration sensor is:

[0110] (3);

[0111] wherein, is the scale factor frequency response, is the power spectral density of the sampled voltage waveform.

[0112] The power spectral density of the noise equivalent angular position of the micro angular vibration sensor is:

[0113] (4);

[0114] wherein, is the power spectral density of the sampled voltage waveform, is the scale factor frequency response, is the input angular vibration frequency.

[0115] The noise equivalent angular rate of the micro angular vibration sensor is:

[0116] (5);

[0117] The noise equivalent angular position of the micro angular vibration sensor is:

[0118] (6);

[0119] wherein, in formula (5) and formula (6), is the input angular vibration frequency, unless otherwise specified, , .

[0120] As can be seen from Formulas (2)-(6), increasing the noise equivalent angular rate and the noise equivalent angular position can reduce the noise power spectral density of the micro angular vibration sensor or increase the scale factor of the micro angular vibration sensor.

[0121] For sensors with multiple sensitive components connected in series, in order to ensure the same magnetic induction intensity for each sensitive component, high requirements are imposed on the design of the magnetic circuit structure. It is necessary to ensure the consistency of the magnetic induction intensity of multiple sensitive components to facilitate theoretical analysis and calculation of the final total output scale.

[0122] In a schematic embodiment, as Figure 1 and Figure 2 shown, the micro angular vibration sensor includes a housing 1, a yoke 2, four permanent magnets 3 arranged at equal intervals in the height direction, and three sensitive components 4 arranged between two adjacent permanent magnets 3. The cavity formed by the base 11, the sleeve 12, and the yoke 2 serves as the sensitive part of the micro angular vibration sensor. A low-noise amplifier circuit 8 is disposed in the gap between the end cap 13 and the yoke 2, and the induced electromotive force (or sensitive signal) of the micro angular vibration sensor is amplified and then output to an external acquisition device to obtain angular vibration information. The low-frequency cut-off frequency of each sensitive component 4 and the three sensitive components 4 connected in series is lower than 2 Hz.

[0123] The three sensitive components 4 include a first sensitive component, a second sensitive component, and a third sensitive component. The outer electrode of the first sensitive component is electrically connected to the first series electrode, the first series electrode is electrically connected to the inner electrode of the second sensitive component, the outer electrode of the second sensitive component is electrically connected to the second series electrode, and the second series electrode is electrically connected to the inner electrode of the third sensitive component. The induced electromotive force of the micro angular vibration sensor is output to the low-noise signal amplifier circuit through the inner electrode of the first sensitive component and the outer electrode of the third sensitive component.

[0124] The four permanent magnets 3 are arranged at equal intervals to provide a constant axial magnetic field for each sensitive component 4. When the sensitive component 4 rotates with the rotating shaft, corresponding induced electromotive forces are generated in the three channels.

[0125] Figure 4 shows the scale test curve graph of the angular vibration sensor according to an embodiment of the present invention, Figure 5 shows the phase test curve graph of the angular vibration sensor according to an embodiment of the present invention, Figure 6 shows the noise test curve graph of the angular vibration sensor according to an embodiment of the present invention.

[0126] As Figure 4 shown, the abscissa represents the frequency (Hz), and the ordinate represents the scale (V / ° / s).

[0127] As Figure 5As shown, the horizontal axis represents frequency (Hz) and the vertical axis represents phase (°).

[0128] like Figure 6 As shown, the horizontal axis represents frequency (Hz) and the vertical axis represents noise (V 2 / Hz).

[0129] like Figure 4 As shown in the figure, when the three channels are tested independently, the output scale factors are very close, indicating that the magnetic induction intensity deviation of the three sensitive components 4 is not large and meets the design requirements. When the three sensitive components 4 are connected in series, the series scale is roughly the sum of the scales of the three independent sensitive components 4 (channel 1 scale, channel 2 scale, and channel 3 scale), that is, the series scale is roughly three times the scale of a single sensitive component 4. Figure 5 As shown, after multiple sensitive components 4 are connected in series, the phases of channel 1, channel 2, and channel 3 are roughly consistent with the series phase, that is, the phase relationship after series connection is roughly consistent with the phase relationship when each sensitive component 4 is tested separately.

[0130] In the noise test, Figure 6 As shown in the figure, the noise of channel 1, channel 2, channel 3 and the series noise are not much different, that is, the noise level of the multi-channel series is still maintained at the same level as the single-channel (single sensitive component) test. Therefore, the multi-channel series structure can improve the noise equivalent angular rate and noise equivalent angular position indicators of the magnetic fluid micro-angular vibration sensor.

[0131] The micro-angular vibration sensor based on magnetohydrodynamics provided in an embodiment of the present invention can realize micro-angular vibration detection. The magnetic induction intensity of each sensitive component 4 has good consistency, and the detection output consistency of a single sensitive component 4 is good. Multiple sensitive components 4 are tested separately and multiple sensitive components 4 are tested in series. The low-frequency cutoff frequency is lower than 2Hz. After being connected in series, it has ultra-low noise, high sensitivity, strong scalability, and high resolution. It can be applied to future higher-precision earth observation aircraft and rotating seismic measuring instruments.

[0132] The magnetohydrodynamic micro-angular vibration sensor, comprising multiple sensitive components 4 connected in series, provided in embodiments of the present invention, offers advantages over traditional gyroscopes, including broadband response, high dynamic range, ultra-low noise, and high sensitivity. In addition to measuring traditional micro-angular vibrations, it also holds great potential for applications in rapid north-finders and microseismic monitoring. By stacking and electrically connecting multiple sensitive components 4 in series, the micro-angular vibration sensor's signal sensitivity is enhanced, enabling research into even higher precision.

[0133] Meanwhile, multiple sensitive components 4 are stacked vertically and in the form of electrical series connection. This not only allows for the expansion of multiple sensitive components 4 according to actual application requirements to increase measurement accuracy, but also enables some of the sensitive components 4 to be used as sensors for sensitive angular velocity, with the remaining channels used for momentum wheels, providing the required active attitude control and attitude stabilization functions for the device, thus realizing the advantage of dual functions in one device.

[0134] The embodiments of the present invention have been described above. However, these embodiments are merely for illustrative purposes and not for limiting the scope of the present invention. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present invention.

Claims

1. An angular vibration sensor based on magnetohydrodynamics, characterized in that, Comprising: A housing, with a cavity formed inside; A yoke, installed inside the cavity; Multiple permanent magnets, stacked and installed inside the cavity in the height direction, and located below the yoke. The cross-section of the permanent magnet in the horizontal plane is circular; Multiple sensitive components, stacked in the height direction between two adjacent permanent magnets. Each sensitive component includes: an annular cavity with a conductive fluid inside, and each annular cavity includes: An inner electrode; Two opposing covers, respectively extending radially outward at the upper and lower ends of the inner electrode; An annular outer electrode, installed between the two covers, and enclosing a closed annular space with the inner electrode and the two covers to confine the conductive fluid within the annular space; Multiple series electrodes, each series electrode including: A first electrode, with the permanent magnet between two adjacent annular cavities located on the first electrode. The first electrode is electrically connected to the outer electrode of one of the two adjacent annular cavities through a screw, and the first electrode is adjacent to one of the covers of the other annular cavity through an insulating gasket; A second electrode, extending from the inner electrode of the other of the two adjacent annular cavities, passing through the insulating gasket to the first electrode, and cooperating with the first electrode to connect the inner electrode of one annular cavity of the two adjacent annular cavities in series with the outer electrode of the other annular cavity.

2. The angular vibration sensor according to claim 1, wherein The average magnetic induction intensity of the multiple sensitive components is consistent.

3. The angular vibration sensor according to claim 2, characterized in that The spacing between two adjacent permanent magnets is equal, and the first spacing between the yoke and the first permanent magnet of the first sensitive component close to the yoke is equal to the second spacing between the bottom wall of the cavity and the second permanent magnet close to the bottom wall.

4. The angular vibration sensor according to claim 3, characterized in that, An adjusting member made of an insulating material is provided between the first permanent magnet and the first sensitive component close to the first permanent magnet to limit the spacing between the first permanent magnet and the permanent magnet adjacent to the first permanent magnet through the adjusting member.

5. The angular vibration sensor according to claim 4, wherein A guiding groove is provided on the adjusting member, and an external wire passes through the guiding groove and is electrically connected to the first sensitive component to lead out the induced electromotive force through the wire.

6. The angular vibration sensor according to claim 1, wherein The housing includes: A base; A sleeve, installed on the base. An upper part of the sleeve extends radially inward to form a flange, and the yoke is installed on the flange; An end cap, installed on the top of the sleeve to cooperate with the base to enclose the cavity formed by the sleeve.

7. The angular vibration sensor according to claim 6, wherein Also including: A signal amplification circuit, installed on the end cap, suitable for amplifying the induced electromotive forces generated by the multiple sensitive components.

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