Angular vibration sensor based on magnetohydrodynamics

Abstract

The invention provides an angular vibration sensor based on magnetohydrodynamics, and the sensor comprises a housing which is internally provided with a cavity; the magnet yoke is mounted in the cavity; the plurality of permanent magnets are stacked in the cavity in the height direction and are positioned below the magnet yoke; the multiple sensitive assemblies are stacked between every two adjacent permanent magnets in the height direction, and each sensitive assembly comprises an annular cavity internally provided with a conductive fluid; wherein the plurality of annular cavities are electrically connected in series, the conductive fluid in each annular cavity rotates around the sensitive shaft based on the input of external angular vibration under the environment of a magnetic field provided by the plurality of permanent magnets, and the sensitive components are electrically connected by utilizing the inertia of the conductive fluid in each sensitive component relative to the annular cavity containing the conductive fluid. And the conductive fluid generates relative motion relative to the annular cavity so as to cut magnetic induction lines to generate induced electromotive force, thereby realizing 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 in particular to a micro-angular vibration sensor based on magnetohydrodynamics. Background Art

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

[0003] However, with the continuous advancement of technology, the accuracy requirements for micro-angular vibration detection in the test and measurement field are also constantly increasing, which makes the traditional magnetic fluid micro-angular vibration sensors face challenges in measurement accuracy. The performance of magnetic fluid micro-angular vibration sensors is gradually unable to meet the increasingly stringent 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 measurement accuracy.

[0005] As one aspect of an embodiment of the present invention, an angular vibration sensor based on magnetohydrodynamics is provided, comprising a shell, a yoke, a plurality of permanent magnets and a plurality of sensitive components. A cavity is formed inside the shell, and the yoke is installed in the cavity; a plurality of permanent magnets are installed in the cavity in a stacked manner in the height direction and are located below the yoke. A plurality of sensitive components are stacked between two adjacent permanent magnets in the height direction, and each of the sensitive components comprises: an annular cavity with a built-in conductive fluid. Among them, the plurality of annular cavities are electrically connected in series, and the conductive fluid in each of the annular cavities rotates around the sensitive axis based on the input of external angular vibration under the magnetic field provided by the plurality of permanent magnets. The inertia of the conductive fluid in each of the sensitive components relative to the annular cavity containing the conductive fluid is utilized to make the conductive fluid move relative to the annular cavity, thereby cutting the magnetic flux lines to generate an induced electromotive force, thereby realizing the measurement of the angular vibration.

[0006] According to an embodiment of the present invention, each of the annular chambers comprises an inner electrode, two opposing covers and an annular outer electrode. The two opposing covers extend radially outward at the upper and lower ends of the inner electrode, respectively, and the annular outer electrode is installed between the two covers and forms a closed annular space with the inner electrode and the two covers, thereby confining the conductive fluid in the annular space.

[0007] According to an embodiment of the present invention, the angular vibration sensor further comprises a plurality of series-connected electrodes, which are located between two adjacent annular cavities and are suitable for connecting in series the inner electrode of one of the two adjacent annular cavities with 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 the two adjacent annular cavities is located on the above-mentioned first electrode, the above-mentioned first electrode is electrically connected to the outer electrode of one of the two adjacent annular cavities, and the above-mentioned 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 through the above-mentioned insulating gasket to the above-mentioned first electrode, and cooperates with the above-mentioned first electrode to connect the inner electrode of one of the two adjacent annular cavities in series with the outer electrode of the other annular cavity.

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

[0010] According to an embodiment of the present invention, the distances between two adjacent permanent magnets are equal, and the first distance between the yoke and the first permanent magnet of the first sensitive component close to the yoke is equal to the second distance between the bottom wall of the 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 insulating material is arranged between the first permanent magnet and the first sensitive component close to the first permanent magnet, so as 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 guide groove is provided on the adjustment member, and an external wire passes through the guide groove to be electrically connected to the first sensitive component, so that the induced electromotive force is led out through the wire.

[0013] According to an embodiment of the present invention, the housing comprises a base, a sleeve and an end cover. The sleeve is mounted on the base, the upper portion of the sleeve radially extends inward to form a flange, and the yoke is mounted on the flange. The end cover is mounted on the top of the sleeve to cooperate with the base to close the cavity surrounded by the sleeve.

[0014] According to an embodiment of the present invention, the angular vibration sensor further comprises a signal amplifying circuit, which is mounted on the end cover and is suitable for amplifying the induced electromotive force generated by the plurality of sensitive components.

[0015] According to the angular vibration sensor based on magnetohydrodynamics of the embodiment of the present invention, by electrically connecting multiple annular cavities in series, it is equivalent to increasing the equivalent radius of the conductive fluid without changing the radial size of the angular vibration sensor. 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, so that the signal-to-noise ratio of the output signal of the angular vibration sensor is higher, thereby achieving higher-precision detection, and can achieve measurements as low as ±0.005rad / s. It has the advantages of strong scalability, high reliability, and wide bandwidth, and provides strong support for future high-precision earth observation, optical payload platform, and line of sight stabilization and suppression. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

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

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

[0019] Figure 3 A circuit diagram of a signal amplifying circuit according to an embodiment of the present invention is shown;

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

[0021] Figure 5 A phase test curve diagram of an angular vibration sensor according to an embodiment of the present invention is shown;

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

[0023] The following are the descriptions of the reference numerals:

[0024] 1- housing;

[0025] 11- base;

[0026] 12-sleeve;

[0027] 13-end cover;

[0028] 2- yoke;

[0029] 3-Permanent magnet;

[0030] 4-Sensitive components;

[0031] 41- conductive fluid;

[0032] 42- annular cavity;

[0033] 421- inner electrode;

[0034] 4211-threaded hole;

[0035] 422-cover;

[0036] 423 - external electrode;

[0037] 5-Electrodes connected in series;

[0038] 51- a first electrode;

[0039] 52- a second electrode;

[0040] 6-Insulation gasket;

[0041] 7-Adjustment parts;

[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- screws;

[0048] 10-Insulation parts. DETAILED DESCRIPTION

[0049] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0050] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence 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] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

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

[0054] In the process of realizing the present invention, it was found that higher and higher requirements are put forward for micro-angular vibration measurement in practical applications. The sensors based on miniaturized design in the past can hardly meet the existing needs. There is an urgent need for micro-angular vibration measurement with an extremely small range below 0.01rad / s. At the same time, it is necessary to avoid the effective signal being submerged in the noise, and put forward stringent technical indicators for the noise of the sensor itself.

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

[0056] (1);

[0057] in, is the output electromotive force; is the input angular velocity; is the average magnetic induction intensity in the fluid area; 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 output electromotive force size.

[0059] However, in practical applications, due to the limitations of the miniaturized application scenarios of the micro-angular vibration sensor based on magnetohydrodynamics, its radial width cannot be simply increased.

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

[0061] As one aspect of an embodiment of the present invention, an angular vibration sensor (or micro-angular vibration sensor) based on magnetohydrodynamics is provided, such as Figure 1 and Figure 2 As shown, the angular vibration sensor includes a shell 1, a yoke 2, a plurality of permanent magnets 3 and a plurality of sensitive components 4. A cavity is formed inside the shell 1, and the yoke 2 is installed in the cavity. A plurality of permanent magnets 3 are installed in the cavity in a stacked manner in the height direction and are located below the yoke 2. A plurality of sensitive components 4 are stacked between two adjacent permanent magnets 3 in the height direction, and each sensitive component 4 includes an annular cavity 42 with a built-in conductive fluid 41. Among them, the plurality of annular cavities 42 are electrically connected in series, and the conductive fluid 41 in each annular cavity 42 rotates around the sensitive axis based on the input of external angular vibration in the environment of the magnetic field provided by the plurality of permanent magnets 3. The inertia of the conductive fluid 41 in each sensitive component 4 relative to the annular cavity 42 containing the conductive fluid 41 is utilized to make the conductive fluid 41 produce relative motion relative to the annular cavity 42, thereby cutting the magnetic flux lines to generate an induced electromotive force, thereby realizing the measurement of angular vibration.

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

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

[0064] In an illustrative embodiment, the low-frequency cutoff frequency of each of the multiple sensitive components 4 is lower than 2 Hz. The total low-frequency cutoff frequency of the multiple sensitive components 4 connected in series is lower than 2 Hz, so that the micro-angular vibration sensor can measure angular vibration signals with lower frequencies, thereby 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 an illustrative embodiment, the number n of sensitive components 4 may include any one of 2, 3, 4, 5 or 6.

[0067] In an illustrative 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, multiple permanent magnets 3 are arranged at equal intervals, and two adjacent permanent magnets 3 provide a constant axial magnetic field for a sensitive component 4 located between the two permanent magnets 3. When the multiple sensitive components 4 rotate around the sensitive axis, the multiple sensitive components 4 respectively generate corresponding induced electromotive forces.

[0069] According to an embodiment of the present invention, Figure 1 As shown, the housing 1 includes a base 11, a sleeve 12 and an end cover 13. The sleeve 12 is mounted on the base 11, and the upper portion of the sleeve 12 extends radially inward to form a flange, and the yoke 2 is mounted on the flange. The end cover 13 is mounted on the top of the sleeve 12 to cooperate with the base 11 to close the cavity surrounded by the sleeve 12.

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

[0071] In an illustrative embodiment, the base 11 and the sleeve 12 can be made of high magnetic permeability materials, which can form a complete magnetic permeability circuit with the magnetic yoke 2, improve the strength and uniformity of the magnetic field, and effectively isolate external magnetic field interference to ensure 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, each component located inside the cavity needs to be rigidly connected.

[0073] According to an embodiment of the present invention, Figure 1As shown, each annular cavity 42 includes an inner electrode 421, two opposing covers 422 and an annular outer electrode 423. The two opposing covers 422 extend radially outward at the upper and lower ends of the inner electrode 421, respectively. The annular outer electrode 423 is installed between the two covers 422, and forms a closed annular space with the inner electrode 421 and the two covers 422, thereby confining the conductive fluid 41 in the annular space.

[0074] According to an embodiment of the present invention, the two covers 422 are made of a high magnetic permeability material, such as a high magnetic permeability soft magnetic alloy material.

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

[0076] In an illustrative embodiment, the inner electrode 421 includes a main body and two extensions extending radially outward from the main body. The two extensions are located at the upper and lower ends of the main body, and the diameters of the two extensions are smaller than the diameter of the main body. The two covers 422 are annular. The two extensions pass through the middle holes of the two annular covers 422, respectively, and the inner edges of the two annular covers 422 are respectively pressed against the upper and lower ends of the main body.

[0077] The outer electrode 423 is annular, and the middle portion of the outer electrode 423 extends radially inward to form a circle of convex portions. The outer edges of the two annular covers 422 respectively abut against the upper and lower surfaces of the convex portions to seal the annular space.

[0078] In an illustrative embodiment, the inner electrode 421 and the two covers 422 are bonded together by colloid.

[0079] In an illustrative embodiment, the outer electrode 423 and the two covers 422 are bonded together by colloid.

[0080] According to an embodiment of the present invention, Figure 1 and Figure 2 As shown, the micro-angular vibration sensor also includes a plurality of series-connected electrodes 5, which are located between two adjacent annular cavities 42 and are suitable for connecting 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.

[0081] According to the micro-angular vibration sensor based on magnetohydrodynamics of the embodiment of the present invention, the inner electrode 421 of one of the two adjacent annular cavities 42 is connected in series with the outer electrode 423 of the other annular cavity 42 through multiple series electrodes 5, so as to realize the series connection of multiple sensitive components 4, thereby 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 realizing high-precision detection as low as ±0.005rad / s.

[0082] According to an embodiment of the present invention, Figure 1 As 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 connected to 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, the external wire can be extended into the space formed by multiple first gaps and second gaps to lead out the induced electromotive force signal generated by each sensitive component 4 respectively.

[0083] According to an embodiment of the present invention, Figure 1 As 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, and 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 covers 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, through the insulating gasket 6 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 spacer 6 , the electrodes between adjacent annular cavities 42 can be effectively isolated.

[0085] According to an embodiment of the present invention, Figure 1 and Figure 2 As 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 an illustrative embodiment, the first electrode 51 is connected to the outer electrode 423 by a screw 9 (for example, a flat head screw). Furthermore, a threaded hole matching the external thread of the screw 9 is formed on the outer electrode 423, and 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, thereby fixing the first electrode 51 to the outer electrode 423 and the insulating member 10, and ensuring the reliability of the electrical connection between the first electrode 51 and the outer electrode 423.

[0087] In an illustrative embodiment, the second electrode 52 can be a screw (for example, a flat head screw), and the second electrode 52 is threadedly connected to the second electrode 52 from the inner electrode 421 through the insulating gasket 6 to achieve 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 the embodiment of the present invention, the average magnetic induction intensities of the plurality of sensitive components 4 are consistent.

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

[0090] According to an embodiment of the present invention, Figure 1 and Figure 2 As shown, the spacing between two adjacent permanent magnets 3 is equal, and the first spacing 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 spacing 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 in a substantially consistent magnetic field strength, thereby 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 insulating material is provided between the first permanent magnet and the first sensitive component close to the first permanent magnet, so as 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 guide slot 71 is provided on the adjusting member 7 , and an external wire passes through the guide slot 71 and is electrically connected to the first sensitive component 4 , so that the induced electromotive force is led out through the wire.

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

[0095] Figure 3 A circuit diagram of a signal amplifying circuit according to an embodiment of the present invention is shown.

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

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

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

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

[0100] When the angular vibration sensor provided by the present invention is used normally, In+ connects 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 close to the base, and In- connects 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+ connects one of the inner electrode 421 and the outer electrode 423 of the sensitive component 4 to be tested, and In- connects the other of the inner electrode 421 and the outer electrode 423 of the sensitive component 4 to be tested.

[0102] like Figure 3 As 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, and is used to receive the output signal Vout1 of the amplifier A1. The second input terminal of the amplifier A3 is grounded (GND) through the resistor R2, and 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 outputs the amplified signal Vout2.

[0103] The coupling unit 83 includes an amplifier A2, a resistor R1, and a capacitor C. A 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 a second input terminal of the amplifier A2 is grounded (GND).

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

[0105] Noise equivalent angular rate and noise equivalent angular position are important indicators for evaluating magnetic fluid pico-angular vibration sensors, and their definitions are as follows:

[0106] Sampling voltage waveform The power spectral density for:

[0107] (2);

[0108] in, is the average number of segments, Number the data points, is the number of data, is the input angular vibration frequency, is an imaginary unit, is the base of natural logarithms.

[0109] Power Spectral Density of Noise Equivalent Angular Rate of Micro-Angular Vibration Sensor for:

[0110] (3);

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

[0112] Power Spectral Density of Noise Equivalent Angular Position of Micro-Angular Vibration Sensor for:

[0113] (4);

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

[0115] Noise equivalent angular rate of micro-angular vibration sensor for:

[0116] (5);

[0117] Noise Equivalent Angular Position of Micro-Angular Vibration Sensor for:

[0118] (6);

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

[0120] It can be seen from formulas (2)-(6) that improving the noise equivalent angular velocity 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 consistency of the magnetic induction intensity of each sensitive component, very high requirements are placed 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 an illustrative embodiment, Figure 1 and Figure 2 As 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 surrounded 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 built into the gap between the end cover 13 and the yoke 2 to amplify the induced electromotive force (or sensitive signal) of the micro-angular vibration sensor and output it to an external acquisition device to obtain angular vibration information. The low-frequency cutoff frequency of each sensitive component 4 and the three sensitive components 4 connected in series are all lower than 2Hz.

[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 amplification 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 along with the rotating shaft, the three channels generate corresponding induced electromotive forces respectively.

[0125] Figure 4 shows a calibration test curve diagram of an angular vibration sensor according to an embodiment of the present invention, Figure 5 shows a phase test curve diagram of an angular vibration sensor according to an embodiment of the present invention, Figure 6 A noise test curve graph of an angular vibration sensor according to an embodiment of the present invention is shown.

[0126] like Figure 4 As shown, the horizontal axis represents frequency (Hz) and the vertical axis represents scale (V / ° / s).

[0127] like 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, channel 3 and the series phase are roughly consistent, 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 connection is still maintained at the same level as the single-channel (single sensitive component) test. Therefore, the multi-channel series connection structure can improve the noise equivalent angular velocity 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 consistency of each sensitive component 4 is good, 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, and 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, and can be applied to future higher-precision earth observation aircraft and rotating seismic measuring instruments.

[0132] The magnetohydrodynamic micro-angular vibration sensor with multiple sensitive components 4 connected in series according to the embodiment of the present invention has advantages such as broadband response, high dynamic range, ultra-low noise, and high sensitivity compared to traditional gyroscopes. In addition to the measurement of traditional micro-angular vibrations, it has great potential for fast north finders and micro-seismic monitoring. By stacking and electrically connecting multiple sensitive components 4 in series, the micro-angular vibration sensor has a stronger sensitive signal capability and is committed to higher precision research.

[0133] At the same time, multiple sensitive components 4 are highly stacked and electrically connected in series, which can not only expand multiple sensitive components 4 according to actual application needs to increase measurement accuracy, but also allow part of the sensitive components 4 to be used as sensors for sensitive angular velocity, and the remaining channels to be used for momentum wheels, providing the equipment with the required active attitude control and attitude stabilization functions, thereby achieving the advantage of one machine with dual functions.

[0134] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. An angular vibration sensor based on magnetohydrodynamics, characterized in that: include: A shell body, forming a cavity inside; a magnetic yoke mounted in the cavity; A plurality of permanent magnets are stacked and installed in the cavity in a height direction and are located below the magnetic yoke; A plurality of sensitive components are stacked between two adjacent permanent magnets in the height direction, and each of the sensitive components comprises: an annular cavity with a conductive fluid built in; Among them, multiple annular cavities are electrically connected in series, and the conductive fluid in each annular cavity rotates around the sensitive axis based on the input of external angular vibration under the magnetic field environment provided by multiple permanent magnets. The inertia of the conductive fluid in each sensitive component relative to the annular cavity accommodating the conductive fluid is utilized to make the conductive fluid produce relative motion relative to the annular cavity, thereby cutting the magnetic lines of force to generate induced electromotive force, thereby realizing the measurement of the angular vibration.

2. The angular vibration sensor according to claim 1, characterized in that: Each of the annular cavities comprises: Internal electrode; Two opposing covers extend radially outward at upper and lower ends of the inner electrode respectively; The annular outer electrode is installed between the two cover bodies, and forms a closed annular space with the inner electrode and the two cover bodies, thereby confining the conductive fluid in the annular space.

3. The angular vibration sensor according to claim 2, characterized in that: Also includes: A plurality of series-connected electrodes are located between two adjacent annular cavities and are suitable for connecting the inner electrode of one of the two adjacent annular cavities in series with the outer electrode of the other annular cavity.

4. The angular vibration sensor according to claim 3, characterized in that: Each of the series-connected electrodes comprises: A first electrode, a permanent magnet between two adjacent annular cavities is located on the first electrode, the first electrode is electrically connected to an 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; The second electrode extends from the inner electrode of the other of the two annular cavities through the insulating gasket to the first electrode, and cooperates with the first electrode to connect the inner electrode of one of the two adjacent annular cavities in series with the outer electrode of the other annular cavity.

5. The angular vibration sensor according to any one of claims 1 to 4, characterized in that: The average magnetic induction intensity of the plurality of sensitive components is consistent.

6. The angular vibration sensor according to claim 5, characterized in that: The distances between two adjacent permanent magnets are equal, and the first distance between the yoke and the first permanent magnet of the first sensitive component close to the yoke is equal to the second distance between the bottom wall of the cavity and the second permanent magnet close to the bottom wall.

7. The angular vibration sensor according to claim 6, characterized in that: An adjusting member made of insulating material is arranged between the first permanent magnet and a first sensitive component close to the first permanent magnet, so as to limit the distance between the first permanent magnet and the permanent magnet adjacent to the first permanent magnet through the adjusting member.

8. The angular vibration sensor according to claim 7, characterized in that: The adjusting member is provided with a guide groove, and an external wire passes through the guide groove and is electrically connected to the first sensitive component, so that the induced electromotive force is led out through the wire.

9. The angular vibration sensor according to claim 1, characterized in that: The housing comprises: Base; A sleeve is mounted on the base, the upper portion of the sleeve radially extends inward to form a flange, and the yoke is mounted on the flange; The end cover is installed on the top of the sleeve to cooperate with the base to close the cavity surrounded by the sleeve.

10. The angular vibration sensor according to claim 9, characterized in that: Also includes: The signal amplifying circuit is installed on the end cover and is suitable for amplifying the induced electromotive force generated by the plurality of sensitive components.

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