Method for determining background noise of low-noise MHD angular velocity sensor and manufacturing method thereof

Abstract

The present invention provides a method for determining the background noise of a low-noise MHD angular velocity sensor and a manufacturing method thereof. The background noise determination method comprises: determining the parameter values ​​of multiple equivalent components included in the equivalent circuit model of the MHD angular velocity sensor based on the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the primary winding and the secondary winding in the MHD angular velocity sensor, wherein the shape data comprises size data, material data and shape data; determining the noise voltage power spectrum density of the MHD angular velocity sensor based on the parameter values ​​of the multiple equivalent components and the turns ratio of the primary winding to the secondary winding; determining the background noise of the MHD angular velocity sensor based on the noise voltage power spectrum density of the MHD angular velocity sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of background noise determination, and in particular to a background noise determination method and a manufacturing method of a low-noise MHD angular velocity sensor. Background Art

[0002] With the continuous development of space science and technology, especially in the fields of high-resolution earth observation, deep space exploration, laser communication, etc., the requirements for the ability of payloads on spacecraft to maintain stable attitude and precise pointing when performing tasks are getting higher and higher. However, the payload platform is extremely sensitive to the perturbation effect of micro-angular vibration and is easily affected by the micro-angular vibration of space structures. The micro-angular vibration of space structures limits the further improvement of the attitude and pointing control accuracy of high-precision spacecraft payloads.

[0003] Magnetohydrodynamics (MHD) angular velocity sensor is a high-frequency angular motion sensor with the characteristics of low noise, wide bandwidth, miniaturization, long life, etc. It is insensitive to acceleration shock and is currently used for wide-band micro-angular vibration measurement of spacecraft payload platforms. It is a very direct, effective and reliable sensor.

[0004] The background noise is a key parameter to measure the ultimate resolution of MHD angular velocity sensors, which is determined by the sensor elements and detection circuits inside the sensor. However, the calculation process of the background noise involves complex electrical coupling between the sensor elements and the detection circuits. Usually, the predetermined background noise design index can only be achieved through empirical attempts, which increases the difficulty of sensor design, R&D cycle and manufacturing cost. Summary of the invention

[0005] In view of this, the present invention provides a method for determining the background noise of a low-noise MHD angular velocity sensor, comprising: determining the parameter values ​​of multiple equivalent devices included in the equivalent circuit model of the MHD angular velocity sensor based on the respective shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the primary winding and the secondary winding in the MHD angular velocity sensor, the shape data including size data, material data and shape data; determining the noise voltage power spectrum density of the MHD angular velocity sensor based on the respective parameter values ​​of the multiple equivalent devices and the turns ratio of the primary winding to the secondary winding; determining the background noise of the MHD angular velocity sensor based on the noise voltage power spectrum density of the MHD angular velocity sensor.

[0006] Optionally, the above-mentioned multiple equivalent devices include a conductive equivalent resistance, an upper equivalent resistance, a lower equivalent resistance, an upper contact equivalent resistance, a lower contact equivalent resistance, an equivalent resistance of the above-mentioned primary winding, an equivalent inductance of the above-mentioned primary winding and an equivalent resistance of the above-mentioned secondary winding, wherein the above-mentioned conductive equivalent resistance characterizes the equivalent resistance of the above-mentioned conductive fluid ring, the above-mentioned upper equivalent resistance characterizes the equivalent resistance of the above-mentioned upper electrode on the current path of the above-mentioned MHD angular velocity sensor, the above-mentioned lower equivalent resistance characterizes the equivalent resistance of the above-mentioned lower electrode on the above-mentioned current path, the above-mentioned upper contact equivalent resistance characterizes the equivalent resistance of the contact surface between the above-mentioned conductive fluid ring and the above-mentioned upper electrode, and the above-mentioned lower contact equivalent resistance characterizes the equivalent resistance of the contact surface between the above-mentioned conductive fluid ring and the above-mentioned lower electrode.

[0007] Optionally, based on the respective shape data of the upper electrode, lower electrode, conductive fluid ring, magnetic core, primary winding and secondary winding in the MHD angular velocity sensor, the parameter values ​​of the multiple equivalent devices included in the equivalent circuit model of the MHD angular velocity sensor are determined, including: determining the parameter value of the conductive equivalent resistance based on the shape data of the conductive fluid ring; determining the parameter value of the upper equivalent resistance based on the shape data of the upper electrode; determining the parameter value of the lower equivalent resistance based on the shape data of the lower electrode; determining the parameter value of the upper contact equivalent resistance based on the respective shape data of the upper electrode and the conductive fluid ring; determining the parameter value of the lower contact equivalent resistance based on the respective shape data of the lower electrode and the conductive fluid ring; determining the parameter value of the equivalent resistance of the primary winding based on the shape data of the primary winding; determining the parameter value of the equivalent resistance of the secondary winding based on the shape data of the secondary winding; determining the parameter value of the equivalent inductance of the primary winding based on the shape data of the magnetic core and the number of turns of the primary winding.

[0008] Optionally, the equivalent circuit model is composed of a sensing element, a transformer and an amplifier; the noise voltage power spectral density of the MHD angular velocity sensor is determined based on the parameter values ​​of each of the multiple equivalent devices and the turns ratio of the primary winding to the secondary winding, including: determining the noise voltage power spectral density of the equivalent resistance of the sensing element, the noise voltage power spectral density of the equivalent resistance of the primary winding, and the noise voltage power spectral density of the equivalent resistance of the secondary winding based on the parameter values ​​of each of the multiple equivalent devices; determining the low-frequency cutoff frequency after the transformer and the amplifier are connected based on the equivalent resistance of the sensing element, the equivalent resistance of the primary winding, and the equivalent inductance of the primary winding; determining the noise voltage power spectral density of the MHD angular velocity sensor based on the gain of the amplifier, the noise voltage power spectral density of the amplifier, the low-frequency cutoff frequency after the transformer and the amplifier are connected, the turns ratio, the noise voltage power spectral density of the equivalent resistance of the sensing element, the noise voltage power spectral density of the equivalent resistance of the primary winding, and the noise voltage power spectral density of the equivalent resistance of the secondary winding.

[0009] Optionally, the above-mentioned determination of the noise voltage power spectrum density of the equivalent resistance of the above-mentioned sensor element, the noise voltage power spectrum density of the equivalent resistance of the above-mentioned primary winding, and the noise voltage power spectrum density of the equivalent resistance of the above-mentioned secondary winding based on the parameter values ​​of each of the above-mentioned multiple equivalent devices includes: obtaining the equivalent resistance of the sensor element in the equivalent circuit model of the above-mentioned MHD angular velocity sensor based on the above-mentioned conductive equivalent resistance, the above-mentioned upper equivalent resistance, the above-mentioned lower equivalent resistance, the above-mentioned upper contact equivalent resistance, and the above-mentioned lower contact equivalent resistance; the above-mentioned determination of the noise voltage power spectrum density of the equivalent resistance of the above-mentioned sensor element based on the equivalent resistance of the above-mentioned sensor element; the above-mentioned determination of the noise voltage power spectrum density of the equivalent resistance of the above-mentioned primary winding based on the equivalent resistance of the above-mentioned primary winding; the above-mentioned determination of the noise voltage power spectrum density of the equivalent resistance of the above-mentioned secondary winding based on the equivalent resistance of the above-mentioned secondary winding.

[0010] Optionally, the determining the background noise of the MHD angular velocity sensor based on the noise voltage power spectrum density of the MHD angular velocity sensor includes: determining the noise angular velocity power spectrum density of the MHD angular velocity sensor based on the noise voltage power spectrum density of the MHD angular velocity sensor; determining the noise angular position power spectrum density of the MHD angular velocity sensor based on the noise angular velocity power spectrum density of the MHD angular velocity sensor; determining a first background noise index based on the noise angular velocity power spectrum density of the MHD angular velocity sensor and a specified frequency range; determining a second background noise index based on the noise angular position power spectrum density of the MHD angular velocity sensor and the specified frequency range; wherein the first background noise index and the second background noise index characterize the background noise of the MHD angular velocity sensor.

[0011] The present invention also provides a method for manufacturing a low-noise MHD angular velocity sensor, comprising: determining the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding and the secondary winding in the MHD angular velocity sensor based on the shape constraints, wherein the shape data includes size data, material data and shape data; determining the parameter values ​​of the multiple equivalent devices included in the equivalent circuit model of the MHD angular velocity sensor based on the parameter values ​​of the multiple equivalent devices and the shape parameters of the magnet; determining the noise angular velocity power spectrum density at the input end of the sensor element based on the parameter values ​​of the multiple equivalent devices and the shape parameters of the magnet. degree; when it is determined that the noise angular velocity power spectrum density at the input end of the above-mentioned sensor element meets the first predetermined noise angular velocity power spectrum density condition, the noise angular velocity power spectrum density of the above-mentioned MHD angular velocity sensor is determined based on the parameter values ​​of each of the above-mentioned multiple equivalent devices and the turns ratio of the above-mentioned primary winding to the above-mentioned secondary winding; when it is determined that the noise angular velocity power spectrum density of the above-mentioned MHD angular velocity sensor meets the second predetermined noise angular velocity power spectrum density condition, the gain of the amplifier is determined; based on the shape data of the above-mentioned upper electrode, the above-mentioned lower electrode, the above-mentioned conductive fluid ring, the above-mentioned magnetic core, the above-mentioned magnet, the above-mentioned primary winding and the above-mentioned secondary winding, the above-mentioned turns ratio, and the gain of the above-mentioned amplifier, the above-mentioned MHD angular velocity sensor is manufactured.

[0012] Optionally, the manufacturing method of a low-noise MHD angular velocity sensor further includes: when it is determined that the noise angular velocity power spectrum density at the input end of the above-mentioned sensor element does not meet the first predetermined noise angular velocity power spectrum density condition, adjusting the respective shape data of the above-mentioned upper electrode, the above-mentioned lower electrode, the above-mentioned conductive fluid ring, the above-mentioned magnetic core, the above-mentioned magnet, the above-mentioned primary winding and the above-mentioned secondary winding; based on the adjusted respective shape data of the above-mentioned upper electrode, the above-mentioned lower electrode, the above-mentioned conductive fluid ring, the above-mentioned magnetic core, the above-mentioned magnet, the above-mentioned primary winding and the above-mentioned secondary winding, re-determining the noise angular velocity power spectrum density at the input end of the above-mentioned sensor element.

[0013] Optionally, the manufacturing method of a low-noise MHD angular velocity sensor further includes: when it is determined that the noise angular velocity power spectrum density of the above-mentioned MHD angular velocity sensor does not meet a second predetermined noise angular velocity power spectrum density condition, adjusting the respective shape data of the above-mentioned upper electrode, the above-mentioned lower electrode, the above-mentioned conductive fluid ring, the above-mentioned magnetic core, the above-mentioned magnet, the above-mentioned primary winding and the above-mentioned secondary winding, and the above-mentioned turns ratio; based on the adjusted respective shape data of the above-mentioned upper electrode, the above-mentioned lower electrode, the above-mentioned conductive fluid ring, the above-mentioned magnetic core, the above-mentioned magnet, the above-mentioned primary winding and the above-mentioned secondary winding, re-determining the noise angular velocity power spectrum density of the above-mentioned MHD angular velocity sensor.

[0014] The present invention also provides an angular velocity detection method, comprising: obtaining an initial angular velocity detected by an MHD angular velocity sensor; updating the initial angular velocity based on the background noise of the MHD angular velocity sensor to obtain a target angular velocity; wherein the background noise of the MHD angular velocity sensor is determined using the background noise determination method of a low-noise MHD angular velocity sensor as described above.

[0015] According to an embodiment of the present invention, based on the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the primary winding and the secondary winding in the MHD angular velocity sensor, the parameter values ​​of the multiple equivalent devices included in the equivalent circuit model of the MHD angular velocity sensor can be determined more accurately. Based on the parameter values ​​of the multiple equivalent devices and the turns ratio of the primary winding to the secondary winding, the noise voltage power spectrum density of the MHD angular velocity sensor can be determined more accurately, so that the background noise of the MHD angular velocity sensor can be determined more accurately. When the MHD angular velocity sensor is used to measure the payload platform, the measurement result of the MHD angular velocity sensor can be compensated according to the background noise of the MHD angular velocity sensor. Using the compensated measurement result to control the payload can improve the stability of the payload attitude and the pointing accuracy of the payload. 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 The flowchart of the method for determining the background noise of a low-noise MHD angular velocity sensor according to an embodiment of the present invention is schematically shown.

[0018] Figure 2 An exploded view of a sensing element and a transformer according to an embodiment of the present invention is shown.

[0019] Figure 3 A cross-sectional view of a sensing element and a transformer according to an embodiment of the present invention is shown.

[0020] Figure 4 An equivalent circuit model of a sensor element according to an embodiment of the present invention is shown.

[0021] Figure 5 An equivalent circuit model of an MHD angular velocity sensor according to an embodiment of the present invention is shown.

[0022] Figure 6 The equivalent circuit model of the MHD angular velocity sensor after adding a noise marker according to an embodiment of the present invention is shown.

[0023] Figure 7 An equivalent subcircuit model diagram of an amplifier according to an embodiment of the present invention is schematically shown.

[0024] Figure 8 The flowchart schematically shows a method for manufacturing a low-noise MHD angular velocity sensor according to an embodiment of the present invention.

[0025] Fig. 9 The flowchart of the angular velocity detection method according to the embodiment of the present invention is schematically shown.

[0026] Reference numerals

[0027] 1. Outer shell; 2. Upper cover; 3. Outer cylinder; 4. Upper electrode; 5. Lower electrode; 6. Magnetic inner cylinder; 7. Upper isolating ring; 8. Lower isolating ring; 9. Upper permanent magnet; 10. Lower permanent magnet; 11. Upper yoke; 12. Lower yoke; 13. Upper magnetic ring; 14. Lower magnetic ring; 15. Conductive fluid ring; 16. Transformer; 161. Magnetic core; 162. Primary winding; 163. Secondary winding. DETAILED DESCRIPTION

[0028] Below, 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 present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0029] 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 features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0030] All terms (including technical and scientific terms) used herein 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.

[0031] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not 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.).

[0032] The background noise is a key parameter to measure the ultimate resolution of MHD angular velocity sensors, which is determined by the sensor elements and detection circuits inside the sensor. However, the calculation process of the background noise involves complex electrical coupling between the sensor elements and the detection circuits. Usually, the predetermined background noise design index can only be achieved through empirical attempts, which increases the difficulty of sensor design, R&D cycle and manufacturing cost.

[0033] In view of the above problems, an embodiment of the present invention provides a method for determining the background noise of a low-noise MHD angular velocity sensor. The method includes: determining the parameter values ​​of multiple equivalent devices included in the equivalent circuit model of the MHD angular velocity sensor based on the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the primary winding and the secondary winding in the MHD angular velocity sensor, wherein the shape data includes size data, material data and shape data. Based on the parameter values ​​of the multiple equivalent devices and the turns ratio of the primary winding to the secondary winding, the noise voltage power spectrum density of the MHD angular velocity sensor is determined. Based on the noise voltage power spectrum density of the MHD angular velocity sensor, the background noise of the MHD angular velocity sensor is determined.

[0034] The following will be passed Figure 1 to Figure 7 A method for determining the background noise of a low-noise MHD angular velocity sensor according to an embodiment of the present invention is described in detail.

[0035] Figure 1 The flowchart of the method for determining the background noise of a low-noise MHD angular velocity sensor according to an embodiment of the present invention is schematically shown. Figure 2 An exploded view of a sensing element and a transformer according to an embodiment of the present invention is shown. Figure 3 A cross-sectional view of a sensing element and a transformer according to an embodiment of the present invention is shown.

[0036] like Figure 1 As shown, the method 100 for determining the background noise of the low-noise MHD angular velocity sensor of this embodiment includes the following operations S110 to S130.

[0037] In operation S110 , parameter values ​​of a plurality of equivalent components included in an equivalent circuit model of the MHD angular velocity sensor are determined based on shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the primary winding, and the secondary winding in the MHD angular velocity sensor.

[0038] According to an embodiment of the present invention, the shape data may be data that affects the performance of each physical device in the MHD angular velocity sensor. For example, data that affects the conductivity of the upper electrode, the lower electrode, the conductive fluid ring, the primary winding and the secondary winding, and data that affects the magnetic properties of the magnetic core. The shape data may include size data, material data and shape data. The size data may include length, height, width, cross-sectional area, etc. The material data may include copper, iron, aluminum, etc. The shape data may include cylindrical, tubular, annular, winding direction, etc.

[0039] According to an embodiment of the present invention, the MHD angular velocity sensor may be composed of a sensing element, a transformer and an amplifier. The sensing element may convert an external angular velocity input into a motional electromotive force output. Figure 2 and Figure 3As shown, the sensing element may include a housing 1, an upper cover 2, an outer cylinder 3, an upper electrode 4, a lower electrode 5, a magnetic inner cylinder 6, an upper isolating ring 7, a lower isolating ring 8, a magnet, an upper magnetic yoke 11, a lower magnetic yoke 12, an upper magnetic ring 13, and a lower magnetic ring 14. The magnet may include an upper permanent magnet 9 and a lower permanent magnet 10. The housing 1 and the upper cover 2 may form a closed space. The outer cylinder 3 may be arranged inside the closed space. The upper electrode 4 and the lower electrode 5 may be located at the top and the bottom of the outer cylinder 3, respectively. The upper electrode 4 and the lower electrode 5 may be cap-shaped. The magnetic inner cylinder 6 may be arranged between the upper electrode 4 and the lower electrode 5 and located at the brim of the cap. A conductive fluid may be filled between the inner wall of the outer cylinder 3 and the outer wall of the magnetic inner cylinder 6 to form a conductive fluid ring 15. The upper electrode 4 and the lower electrode 5 may be provided with through holes, respectively. The through holes may be provided with an upper isolating ring 7, a lower isolating ring 8, an upper magnetic yoke 11, and a lower magnetic yoke 12, respectively. An upper permanent magnet 9 and a lower permanent magnet 10 are arranged in the upper isolation ring 7 and the lower isolation ring 8. The transformer 16 can be arranged between the upper electrode 4 and the lower electrode 5 and located at the cap body. The transformer 16 can be composed of a magnetic core 161, a primary winding 162 and a secondary winding 163. The upper magnetic ring 13 and the lower magnetic ring 14 can be respectively sleeved on the upper magnetic yoke 11 and the lower magnetic yoke 12. The transformer 16 can be arranged inside the sensing element. The secondary winding 163 can be wound on the magnetic core 161, and the primary winding 162 can be wound on the secondary winding 163. The conductive fluid can generate an electrical signal under the action of the external angular velocity, and the electrical signal can flow out from the conductive fluid ring 15, flow through the upper electrode 4, the primary winding 162 and the lower electrode 5, and return to the conductive fluid ring 15, thereby forming a current path in the sensing element.

[0040] According to an embodiment of the present invention, an equivalent circuit model of the MHD angular velocity sensor can be used to represent the electrical characteristics of the MHD angular velocity sensor. The equivalent circuit model can be a resistance model, an impedance model and / or a mutual inductance model.

[0041] According to the embodiment of the present invention, the equivalent device can be used to simulate the electrical characteristics of each physical device in the MHD angular velocity sensor. The parameter value of the equivalent device can represent the specific situation of the electrical characteristics of the physical device.

[0042] In operation S120 , a noise voltage power spectrum density of the MHD angular velocity sensor is determined based on parameter values ​​of the respective equivalent devices and a turns ratio of the primary winding to the secondary winding.

[0043] In operation S130 , a noise floor of the MHD angular velocity sensor is determined based on a noise voltage power spectrum density of the MHD angular velocity sensor.

[0044] According to an embodiment of the present invention, based on the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the primary winding and the secondary winding in the MHD angular velocity sensor, the parameter values ​​of the multiple equivalent devices included in the equivalent circuit model of the MHD angular velocity sensor can be determined more accurately. Based on the parameter values ​​of the multiple equivalent devices and the turns ratio of the primary winding to the secondary winding, the noise voltage power spectrum density of the MHD angular velocity sensor can be determined more accurately, so that the background noise of the MHD angular velocity sensor can be determined more accurately. When the MHD angular velocity sensor is used to measure the payload platform, the measurement result of the MHD angular velocity sensor can be compensated according to the background noise of the MHD angular velocity sensor. Using the compensated measurement result to control the payload can improve the stability of the payload attitude and the pointing accuracy of the payload.

[0045] Figure 4 An equivalent circuit model of a sensor element according to an embodiment of the present invention is shown. Figure 5 An equivalent circuit model of an MHD angular velocity sensor according to an embodiment of the present invention is shown. Figure 6 The equivalent circuit model of the MHD angular velocity sensor after adding a noise marker according to an embodiment of the present invention is shown.

[0046] In some embodiments, the plurality of equivalent devices may include a conductive equivalent resistance, an upper equivalent resistance, a lower equivalent resistance, an upper contact equivalent resistance, a lower contact equivalent resistance, an equivalent resistance of a primary winding, an equivalent inductance of a primary winding, and an equivalent resistance of a secondary winding.

[0047] According to an embodiment of the present invention, Figure 4 As shown, the equivalent device in the sensing element may include a voltage source , Conductive equivalent resistance , upper equivalent resistance (not shown in the figure), lower equivalent resistance (not shown in the figure), upper contact equivalent resistance (not shown in the figure), lower contact equivalent resistance (not shown in the figure) and stray inductance .

[0048] According to an embodiment of the present invention, a voltage source It can characterize the alternating electromotive force generated by the conductive fluid ring sensitive to the external input angular velocity. Conductive equivalent resistance It can characterize the equivalent resistance of the conductive fluid ring, that is, the conductive equivalent resistance The axial equivalent resistance between the upper and lower end surfaces of the conductive fluid ring can be characterized.

[0049] According to an embodiment of the present invention, the upper equivalent resistance can represent the equivalent resistance of the upper electrode on the current path of the MHD angular velocity sensor, that is, it can be the equivalent resistance on the current path in the sensor element. The lower equivalent resistance can represent the equivalent resistance of the lower electrode on the current path. Figure 4 As shown, the upper equivalent resistance and the lower equivalent resistance can be obtained by the electrode equivalent resistance Indicates. Electrode equivalent resistance It can be the sum of the upper equivalent resistance and the lower equivalent resistance.

[0050] According to an embodiment of the present invention, the upper contact equivalent resistance can represent the equivalent resistance of the contact surface between the conductive fluid ring and the upper electrode. The lower contact equivalent resistance can represent the equivalent resistance of the contact surface between the conductive fluid ring and the lower electrode. Figure 4 As shown, the upper contact equivalent resistance and the lower contact equivalent resistance can be expressed by the contact equivalent resistance Indicates. Contact equivalent resistance It can be the sum of the upper contact equivalent resistance and the lower contact equivalent resistance.

[0051] Furthermore, the conductive equivalent resistance , electrode equivalent resistance And the contact equivalent resistance The equivalent resistance of the sensing element express.

[0052] Furthermore, the stray inductance It is formed by the current path surrounding the magnetic inner cylinder. It can be shown as the following formula (1).

[0053] (1).

[0054] in, It can be the magnetic permeability of vacuum. It can be the relative magnetic permeability of the magnetic inner cylinder. It can be the height of the magnetic inner cylinder. It can be the outer diameter of the magnetic inner cylinder. It can be the inner diameter of the magnetic inner cylinder.

[0055] Furthermore, within the signal bandwidth range of 0.1Hz~1kHz and the voltage signal source amplitude of tens of microvolts, due to the stray inductance The energy storage is very small, and the stray inductance can be ignored. Thus, we can get Figure 5 The equivalent circuit model of the MHD angular velocity sensor is shown.

[0056] like Figure 5 As shown, according to an embodiment of the present invention, the equivalent device in the transformer may include an equivalent resistor of the primary winding. , the equivalent inductance of the primary winding And the equivalent resistance of the secondary winding The equivalent resistance of the primary winding is The equivalent DC resistance of the primary winding can be The equivalent magnetizing inductance of the primary winding can be the equivalent resistance of the secondary winding. It can be the equivalent DC resistance of the secondary winding. It can be expressed as the output voltage of the MHD angular velocity sensor.

[0057] Furthermore, within the signal bandwidth range of 0.1 Hz to 1 kHz, the voltage noise output by the sensor element can be The thermal noise generated, the voltage noise output by the sensing element can be expressed as The voltage noise of the primary winding output can be due to the equivalent resistance of the primary winding. The thermal noise generated, the voltage noise of the primary winding output can be expressed as The voltage noise of the secondary winding output can be due to the equivalent resistance of the secondary winding. The thermal noise generated, the voltage noise of the secondary winding output can be expressed as The input voltage noise of the amplifier and the equivalent input current noise of the amplifier can be obtained from the workbook of the selected amplifier. The input voltage noise of the amplifier can be expressed as The equivalent input current noise of the amplifier can be expressed as Thus, we can get Figure 6 The equivalent circuit model of the MHD angular velocity sensor shown in the figure is added with noise marker. It can be expressed as the voltage noise output by the MHD angular velocity sensor.

[0058] In some embodiments, operation S110 may include the following operations S111 to S118.

[0059] In operation S111 , a parameter value of a conductive equivalent resistance is determined based on the shape data of the conductive fluid ring.

[0060] According to an embodiment of the present invention, the parameter value of the conductive equivalent resistance may be the resistance value of the conductive equivalent resistance, which may be calculated based on the shape data of the conductive fluid ring using the resistance law. It can be expressed by the following formula (2).

[0061] (2).

[0062] in, Can be the height of the conductive fluid ring. This can be the outer diameter of the conductive fluid ring. This can be the inner diameter of the conductive fluid ring. It can be the conductivity of the conductive fluid.

[0063] In operation S112, a parameter value of an upper equivalent resistor is determined based on the shape data of the upper electrode.

[0064] According to an embodiment of the present invention, the parameter value of the upper equivalent resistor may be the resistance value of the upper equivalent resistor, which may be calculated using a numerical method, for example, by a finite element method based on the shape data of the upper electrode.

[0065] In operation S113, a parameter value of a lower equivalent resistor is determined based on the shape data of the lower electrode.

[0066] According to an embodiment of the present invention, the parameter value of the lower equivalent resistor may be the resistance value of the lower equivalent resistor, which may be calculated using a numerical method, for example, by a finite element method based on the shape data of the lower electrode.

[0067] In operation S114, a parameter value of the upper contact equivalent resistance is determined based on the respective shape data of the upper electrode and the conductive fluid ring.

[0068] According to an embodiment of the present invention, the parameter value of the upper contact equivalent resistance may be the resistance value of the upper contact equivalent resistance, which may be calculated using a numerical method, for example, by a finite element method based on the shape data of the upper electrode and the conductive fluid ring.

[0069] In operation S115 , a parameter value of the lower contact equivalent resistance is determined based on the respective shape data of the lower electrode and the conductive fluid ring.

[0070] According to an embodiment of the present invention, the parameter value of the lower contact equivalent resistance may be the resistance value of the lower contact equivalent resistance, which may be calculated using a numerical method, for example, by a finite element method based on the shape data of the lower electrode and the conductive fluid ring.

[0071] In operation S116 , a parameter value of an equivalent resistance of the primary winding is determined based on the shape data of the primary winding.

[0072] According to an embodiment of the present invention, the parameter value of the equivalent resistance of the primary winding may be the resistance value of the equivalent resistance of the primary winding, which may be calculated based on the shape data of the primary winding using the basic resistance formula. For example, the resistance value of the equivalent resistance of the primary winding is It can be expressed by the following formula (3).

[0073] (3).

[0074] in, This may be the resistivity of the material of the primary winding. Can be the length of the primary winding. The cross-sectional area of ​​the conductor after the primary winding is wound around the magnetic core.

[0075] In operation S117 , a parameter value of an equivalent resistance of the secondary winding is determined based on the shape data of the secondary winding.

[0076] According to an embodiment of the present invention, the parameter value of the equivalent resistance of the secondary winding may be the resistance value of the equivalent resistance of the secondary winding, which may be calculated based on the shape data of the secondary winding using the basic resistance formula. It can be expressed by the following formula (4).

[0077] (4).

[0078] in, It can be the resistivity of the material of the secondary winding. Can be the length of the secondary winding. It can be the cross-sectional area of ​​the conductor after the secondary winding is wound.

[0079] In operation S118 , a parameter value of an equivalent inductance of the primary winding is determined based on the shape data of the magnetic core, the shape data of the primary winding, and the number of turns of the primary winding.

[0080] According to an embodiment of the present invention, the parameter value of the equivalent inductance of the primary winding may be the inductance value of the equivalent inductance of the primary winding, which may be calculated using an electromagnetic calculation formula based on the shape data of the magnetic core and the number of turns of the primary winding. It can be expressed by the following formula (5).

[0081] (5).

[0082] in, Can be the number of primary turns. It can be the magnetic permeability of the magnetic core. It can be the cross-sectional area of ​​the core. The average length of the magnetic circuit can be obtained based on the shape data of the magnetic core, the magnetic permeability of the magnetic core, the cross-sectional area of ​​the magnetic core and the average length of the magnetic circuit.

[0083] In some embodiments, the equivalent circuit model may be composed of a sensor element, a transformer, and an amplifier. Operation S120 may include the following operations S121 to S123.

[0084] In operation S121 , noise voltage power spectrum density of an equivalent resistance of a sensing element, noise voltage power spectrum density of an equivalent resistance of a primary winding, and noise voltage power spectrum density of an equivalent resistance of a secondary winding are determined based on respective parameter values ​​of a plurality of equivalent devices.

[0085] In operation S122, a low frequency cutoff frequency after the transformer and the amplifier are connected is determined based on an equivalent resistance of the sensing element, an equivalent resistance of the primary winding, and an equivalent inductance of the primary winding.

[0086] According to an embodiment of the present invention, the low frequency cutoff frequency after the transformer and the amplifier are connected is It can be expressed by the following formula (6).

[0087] (6).

[0088] in, It can be the equivalent resistance of the primary winding. It can be the equivalent resistance of the sensing element.

[0089] In operation S123, the noise voltage power spectral density of the MHD angular velocity sensor is determined based on the gain of the amplifier, the noise voltage power spectral density of the amplifier, the low-frequency cutoff frequency after the transformer and the amplifier are connected, the turns ratio, the noise voltage power spectral density of the equivalent resistance of the sensing element, the noise voltage power spectral density of the equivalent resistance of the primary winding, and the noise voltage power spectral density of the equivalent resistance of the secondary winding.

[0090] According to an embodiment of the present invention, the noise voltage power spectrum density of the MHD angular velocity sensor is It can be expressed by the following formula (7).

[0091] (7).

[0092] in, is the transfer function after the transformer and amplifier are connected in the MHD angular velocity sensor. Can be a complex frequency. It can be the angular frequency. Can be an imaginary unit. The noise voltage power spectral density can be the equivalent resistance of the sensing element. The noise voltage power spectral density can be given by the equivalent resistance of the primary winding. The noise voltage power spectral density can be given by the equivalent resistance of the secondary winding. It can be the noise voltage power spectral density of the amplifier. It can be the noise current power spectral density of the amplifier. It can be obtained from the equivalent input voltage noise of the amplifier. It can be obtained from the equivalent input current noise of the amplifier. Can be the gain of the amplifier. It can be the turns ratio of the primary winding to the secondary winding.

[0093] Furthermore, the transfer function of the transformer and amplifier in the MHD angular velocity sensor is It can be expressed by the following formula (8).

[0094] (8).

[0095] Figure 7 An equivalent subcircuit model diagram of an amplifier according to an embodiment of the present invention is schematically shown.

[0096] like Figure 7 As shown, the amplifier may be an active amplifier. The active amplifier may be provided with three operational amplifiers. The equivalent subcircuit model includes a first operational amplifier , the second operational amplifier , the third operational amplifier , the first resistor , the second resistor , the third resistor , the fourth resistor , the fifth resistor , the sixth resistor , the seventh resistor , the eighth resistor 、Ninth resistor and the first capacitor . The first resistor , the second resistor and the third resistor The fourth resistor is connected in series to form a first branch. , the fifth resistor and the first capacitor The sixth resistor is connected in series to form a second branch. , the seventh resistor and the third operational amplifier A third branch is formed. The third operational amplifier The output terminal of the third operational amplifier is used as the output of the active amplifier. The output terminal and the sixth resistor An eighth resistor is provided between The first branch, the second branch and the third branch are connected in parallel. The first operational amplifier The negative input terminal is connected to the first resistor and the second resistor The second operational amplifier The negative input terminal is connected to the third resistor and the second resistor The first operational amplifier The output terminal is connected to the first resistor and the fourth resistor The second operational amplifier The output terminal is connected to the third resistor and the fifth resistor between.

[0097] Furthermore, the gain of the amplifier It can be expressed by the following formula (9).

[0098] (9).

[0099] In some embodiments, operation S121 may include the following operations S1211 to S1214.

[0100] In operation S1211, an equivalent resistance of a sensing element in an equivalent circuit model of the MHD angular velocity sensor is obtained based on the conductive equivalent resistance, the upper equivalent resistance, the lower equivalent resistance, the upper contact equivalent resistance, and the lower contact equivalent resistance.

[0101] According to an embodiment of the present invention, the equivalent resistance of the sensor element It can be shown as the following formula (10).

[0102] (10).

[0103] In operation S1212 , based on the equivalent resistance of the sensing element, a noise voltage power spectrum density of the equivalent resistance of the sensing element is determined.

[0104] According to an embodiment of the present invention, the noise voltage power spectrum density of the equivalent resistance of the sensor element is It can be shown as the following formula (11).

[0105] (11).

[0106] in, can be the Boltzmann constant, Can be the absolute temperature of the sensing element.

[0107] In operation S1213 , based on the equivalent resistance of the primary winding, a noise voltage power spectrum density of the equivalent resistance of the primary winding is determined.

[0108] According to an embodiment of the present invention, the noise voltage power spectrum density of the equivalent resistance of the primary winding is It can be shown as the following formula (12).

[0109] (12).

[0110] in, It can be the absolute temperature of the primary winding.

[0111] In operation S1214, based on the equivalent resistance of the secondary winding, a noise voltage power spectrum density of the equivalent resistance of the secondary winding is determined.

[0112] According to an embodiment of the present invention, the noise voltage power spectrum density of the equivalent resistance of the secondary winding is It can be shown as the following formula (13).

[0113] (13).

[0114] in, Can be the absolute temperature of the secondary winding.

[0115] In some embodiments, operation S130 may include the following operations S131 to S134.

[0116] In operation S131 , a noise angular velocity power spectrum density of the MHD angular velocity sensor is determined based on a noise voltage power spectrum density of the MHD angular velocity sensor.

[0117] According to the embodiment of the present invention, the absolute temperature of the entire MHD angular velocity sensor is ,Right now , the noise angular velocity power spectrum density of the MHD angular velocity sensor It can be shown as the following formula (14).

[0118] (14).

[0119] in, It can be the amplitude-frequency response function of the sensing element.

[0120] Furthermore, the amplitude-frequency response function of the sensor element is It can be expressed by the following formula (15).

[0121] (15).

[0122] in, It can be the average magnetic induction intensity in the conductive fluid ring. . Average magnetic induction intensity It can be expressed by the following formula (16).

[0123] (16).

[0124] in, can be the working point magnetic flux density of the magnet, can be the magnetic pole area of ​​the magnet, It can be the leakage coefficient of the magnetic circuit, for example The working point magnetic flux density and the magnetic pole area of ​​the magnet can be obtained based on the shape parameters of the magnet. The shape parameters of the magnet can include the material of the magnet, the size of the magnet, the shape of the magnet, and the magnetization intensity of the magnet.

[0125] In operation S132, a noise angular position power spectrum density of the MHD angular velocity sensor is determined based on the noise angular velocity power spectrum density of the MHD angular velocity sensor.

[0126] According to an embodiment of the present invention, the noise angular position power spectrum density of the MHD angular velocity sensor is It can be shown as the following formula (17).

[0127] (17).

[0128] in, It can be the angular frequency.

[0129] In operation S133 , a first noise floor index is determined based on a noise angular velocity power spectrum density of the MHD angular velocity sensor and a designated frequency range.

[0130] According to an embodiment of the present invention, the first background noise index It can be shown as the following formula (18).

[0131] (18).

[0132] The specified frequency range is f1~f2. f1 is greater than 0. f2 is greater than 0.

[0133] In operation S134 , a second noise floor index is determined based on the noise angular position power spectrum density of the MHD angular velocity sensor and a designated frequency range.

[0134] According to an embodiment of the present invention, the second background noise index It can be shown as the following formula (19).

[0135] (19).

[0136] The first noise floor index and the second noise floor index can characterize the noise floor of the MHD angular velocity sensor. The first noise floor index can be the positive square root of the noise equivalent angular velocity. The second noise floor index can be the positive square root of the noise equivalent angular position.

[0137] Figure 8 The flowchart schematically shows a method for manufacturing a low-noise MHD angular velocity sensor according to an embodiment of the present invention.

[0138] like Figure 8As shown, the method 800 for manufacturing a low-noise MHD angular velocity sensor according to the embodiment includes the following operations S810 to S860.

[0139] In operation S810, shape data of each of an upper electrode, a lower electrode, a conductive fluid ring, a magnetic core, a magnet, a primary winding, and a secondary winding in the MHD angular velocity sensor are determined based on shape constraints.

[0140] According to an embodiment of the present invention, the appearance data may include size data, material data and shape data.

[0141] According to the embodiment of the present invention, the shape constraint condition can be that the shape data of the upper electrode, lower electrode, conductive fluid ring, magnetic core, magnet, primary winding and secondary winding in the MHD angular velocity sensor meet the shape size limit requirements of the MHD angular velocity sensor.

[0142] In operation S820, parameter values ​​of a plurality of equivalent components included in an equivalent circuit model of the MHD angular velocity sensor are determined based on shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding in the MHD angular velocity sensor.

[0143] According to the embodiment of the present invention, the parameter values ​​of the multiple equivalent devices included in the equivalent circuit model of the MHD angular velocity sensor may be determined in the same manner as in the above operations S110 to S118.

[0144] In operation S830 , a noise angular velocity power spectrum density at an input terminal of the sensing element is determined based on respective parameter values ​​of a plurality of equivalent devices.

[0145] According to an embodiment of the present invention, the noise voltage power spectrum density generated in the current path after the sensing element is coupled to the transformer can be determined based on the parameter values ​​of the multiple equivalent devices. The noise angular velocity power spectrum density at the input end of the sensing element is determined based on the noise voltage power spectrum density generated in the current path after the sensing element is coupled to the transformer.

[0146] Furthermore, the noise voltage power spectral density generated in the current path after the sensing element is coupled to the transformer is It can be shown as the following formula (20).

[0147] (20).

[0148] According to an embodiment of the present invention, the noise angular velocity power spectrum density at the input end of the sensor element is It can be shown as the following formula (21).

[0149] (twenty one).

[0150] In operation S840, when it is determined that the noise angular velocity power spectrum density at the input end of the sensing element satisfies a first predetermined noise angular velocity power spectrum density condition, the noise angular velocity power spectrum density of the MHD angular velocity sensor is determined based on respective parameter values ​​of a plurality of equivalent devices and a turns ratio of the primary winding to the secondary winding.

[0151] According to an embodiment of the present invention, the first predetermined noise angular velocity power spectrum density condition may be that the noise angular velocity power spectrum density at the input end of the sensor element is less than half of the noise equivalent angular velocity power spectrum density design index within the passband. The noise equivalent angular velocity power spectrum density design index may be set based on previous experience.

[0152] According to an embodiment of the present invention, the noise angular velocity power spectrum density of the MHD angular velocity sensor is It can be shown as the following formula (22).

[0153] (twenty two).

[0154] in, is the number of turns of the primary winding, is the number of secondary turns, is the average single-turn resistance of the primary winding, is the average single-turn resistance of the secondary winding.

[0155] In operation S850, in a case where it is determined that the noise angular velocity power spectrum density of the MHD angular velocity sensor satisfies a second predetermined noise angular velocity power spectrum density condition, a gain of the amplifier is determined.

[0156] According to an embodiment of the present invention, the second predetermined noise angular velocity power spectrum density condition may be a condition that meets the normal use requirements of the MHD angular velocity sensor. For example, the second predetermined noise angular velocity power spectrum density condition may be that the noise angular velocity power spectrum density of the MHD angular velocity sensor is less than eighty percent of the noise equivalent angular velocity power spectrum density design index within the passband. The noise equivalent angular velocity power spectrum density design index may be set based on previous experience.

[0157] According to an embodiment of the present invention, the gain of the amplifier It can be shown as the following formula (23).

[0158] (twenty three).

[0159] in, The maximum output voltage swing of the MHD angular velocity sensor can be It can be an angular rate range indicator of the MHD angular rate sensor. It can be the average magnetic induction intensity in the conductive fluid ring. . Can be the height of the conductive fluid ring. This can be the optimal turns ratio for the amplifier.

[0160] In operation S860, the MHD angular velocity sensor is manufactured based on the shape data of each of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding, the turns ratio, and the gain of the amplifier.

[0161] According to an embodiment of the present invention, in formula (22), the minimum value method can be used to find Place, seek right The partial derivative of , set the partial derivative to 0, and find the optimal turns ratio and the optimal noise equivalent angular rate power spectral density. Update the turns ratio to the optimal turns ratio . Noise angular velocity power spectral density Update to the optimal noise equivalent angular velocity power spectral density, use the updated noise angular velocity power spectral density to determine whether a second predetermined noise angular velocity power spectral density condition is met, and after the second predetermined noise angular velocity power spectral density condition is met, use the updated turns ratio to manufacture the MHD angular velocity sensor.

[0162] According to the embodiment of the present invention, by using the manufacturing method of a low-noise MHD angular velocity sensor to manufacture an MHD angular velocity sensor, the development cycle of the MHD angular velocity sensor can be shortened and the development cost can be reduced.

[0163] In some embodiments, the method for manufacturing a low-noise MHD angular velocity sensor may further include: when it is determined that the noise angular velocity power spectrum density at the input end of the sensing element does not meet the first predetermined noise angular velocity power spectrum density condition, adjusting the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding. Based on the adjusted shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding, the noise angular velocity power spectrum density at the input end of the sensing element is re-determined.

[0164] According to an embodiment of the present invention, adjusting the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding can be to increase the size of the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the primary winding, and the secondary winding, thereby reducing the noise angular velocity power spectrum density at the input end of the sensor element. By increasing the shape data of the magnet, the average magnetic induction intensity in the conductive fluid ring can be increased, thereby reducing the noise angular velocity power spectrum density at the input end of the sensor element.

[0165] In some embodiments, the method for manufacturing a low-noise MHD angular velocity sensor may further include: when it is determined that the noise angular velocity power spectrum density of the MHD angular velocity sensor does not meet the second predetermined noise angular velocity power spectrum density condition, adjusting the shape data and turns ratio of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding, respectively. Based on the adjusted shape data and turns ratio of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding, the noise angular velocity power spectrum density of the MHD angular velocity sensor is re-determined.

[0166] According to the embodiment of the present invention, adjusting the shape data and turns ratio of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding and the secondary winding can increase the size of the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding and the secondary winding, thereby reducing the noise angular velocity power spectrum density of the MHD angular velocity sensor. By increasing the shape data of the magnet, the average magnetic induction intensity in the conductive fluid ring can be increased, thereby reducing the noise angular velocity power spectrum density of the MHD angular velocity sensor.

[0167] Fig. 9 The flowchart of the angular velocity detection method according to the embodiment of the present invention is schematically shown.

[0168] like Fig. 9 As shown, the angular velocity detection method 900 of this embodiment includes the following operations S910 to S920.

[0169] In operation S910, an initial angular velocity detected by the MHD angular velocity sensor is acquired.

[0170] In operation S920, the initial angular velocity is updated based on the background noise of the MHD angular velocity sensor to obtain a target angular velocity.

[0171] According to the embodiment of the present invention, the noise floor of the MHD angular velocity sensor is determined by using the noise floor determination method of the low-noise MHD angular velocity sensor as described above.

[0172] According to the embodiment of the present invention, the initial angular velocity is updated based on the background noise of the MHD angular velocity sensor, and the measurement result of the MHD angular velocity sensor can be compensated to obtain the target angular velocity without the influence of the background noise. The payload is controlled by using the compensated target angular velocity, which can improve the stability of the payload attitude and the pointing accuracy of the payload.

[0173] The flow chart in the accompanying drawings illustrates the possible functions of the method according to various embodiments of the present invention. In this regard, each square frame in the flow chart can represent a part of a module, a program segment, or a code, and the part of the above-mentioned module, a program segment, or a code comprises one or more executable instructions for realizing the logical function of the specification. It should also be noted that in some alternative implementations, the function marked in the square frame can also occur in a sequence different from that marked in the accompanying drawings. For example, two square frames represented in succession can actually be performed substantially in parallel, and they can sometimes be performed in the opposite order, depending on the function involved. It should also be noted that each square frame in the flow chart, and the combination of the square frames in the flow chart, can be realized by a special hardware-based system that performs the function or operation of the specification, or can be realized by a combination of special hardware and computer instructions.

[0174] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways, even if such combinations and / or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All of these combinations and / or combinations fall within the scope of the present invention.

[0175] 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. A method for determining the background noise of a low-noise MHD angular velocity sensor, characterized in that: include: Based on the shape data of the conductive fluid ring, a parameter value of the conductive equivalent resistance is determined, the shape data includes size data, material data and shape data, and the conductive equivalent resistance represents the equivalent resistance of the conductive fluid ring; Based on the shape data of the upper electrode, a parameter value of an upper equivalent resistor is determined, where the upper equivalent resistor represents an equivalent resistance of the upper electrode on a current path of the MHD angular velocity sensor; Based on the shape data of the lower electrode, a parameter value of the lower equivalent resistance is determined, where the lower equivalent resistance represents the equivalent resistance of the lower electrode in the current path; Based on the shape data of the upper electrode and the conductive fluid ring, the parameter value of the upper contact equivalent resistance is determined, and the upper contact equivalent resistance represents the equivalent resistance of the contact surface between the conductive fluid ring and the upper electrode; Based on the shape data of the lower electrode and the conductive fluid ring, a parameter value of the lower contact equivalent resistance is determined, where the lower contact equivalent resistance represents the equivalent resistance of the contact surface between the conductive fluid ring and the lower electrode; Determine the parameter value of the equivalent resistance of the primary winding based on the shape data of the primary winding; Determining a parameter value of an equivalent resistance of the secondary winding based on the shape data of the secondary winding; Based on the shape data of the magnetic core and the number of turns of the primary winding, the parameter value of the equivalent inductance of the primary winding is determined; Determining the noise voltage power spectrum density of the MHD angular velocity sensor based on parameter values ​​of multiple equivalent components and a turns ratio of the primary winding to the secondary winding, wherein the multiple equivalent components include a conductive equivalent resistance, an upper equivalent resistance, a lower equivalent resistance, an upper contact equivalent resistance, a lower contact equivalent resistance, an equivalent resistance of the primary winding, an equivalent inductance of the primary winding, and an equivalent resistance of the secondary winding; The background noise of the MHD angular velocity sensor is determined based on the noise voltage power spectral density of the MHD angular velocity sensor.

2. The method for determining the background noise of a low-noise MHD angular velocity sensor according to claim 1, characterized in that: The MHD angular velocity sensor is composed of a sensing element, a transformer and an amplifier; The method of determining the noise voltage power spectrum density of the MHD angular velocity sensor based on the parameter values ​​of the respective equivalent devices and the turns ratio of the primary winding to the secondary winding includes: Determining the noise voltage power spectrum density of the equivalent resistance of the sensing element, the noise voltage power spectrum density of the equivalent resistance of the primary winding, and the noise voltage power spectrum density of the equivalent resistance of the secondary winding based on the respective parameter values ​​of the multiple equivalent devices; Determining a low-frequency cutoff frequency after the transformer and the amplifier are connected based on an equivalent resistance of the sensor element, an equivalent resistance of the primary winding, and an equivalent inductance of the primary winding; The noise voltage power spectral density of the MHD angular velocity sensor is determined based on the gain of the amplifier, the noise voltage power spectral density of the amplifier, the low-frequency cutoff frequency after the transformer and the amplifier are connected, the turns ratio, the noise voltage power spectral density of the equivalent resistance of the sensor element, the noise voltage power spectral density of the equivalent resistance of the primary winding, and the noise voltage power spectral density of the equivalent resistance of the secondary winding.

3. The method for determining the background noise of a low-noise MHD angular velocity sensor according to claim 2, characterized in that: The determining, based on the parameter values ​​of the multiple equivalent devices, the noise voltage power spectrum density of the equivalent resistance of the sensing element, the noise voltage power spectrum density of the equivalent resistance of the primary winding, and the noise voltage power spectrum density of the equivalent resistance of the secondary winding comprises: Based on the conductive equivalent resistance, the upper equivalent resistance, the lower equivalent resistance, the upper contact equivalent resistance and the lower contact equivalent resistance, an equivalent resistance of a sensing element in an equivalent circuit model of the MHD angular velocity sensor is obtained; Determining a noise voltage power spectrum density of the equivalent resistance of the sensing element based on the equivalent resistance of the sensing element; Determining a noise voltage power spectrum density of the equivalent resistance of the primary winding based on the equivalent resistance of the primary winding; Based on the equivalent resistance of the secondary winding, a noise voltage power spectrum density of the equivalent resistance of the secondary winding is determined.

4. The method for determining the background noise of a low-noise MHD angular velocity sensor according to claim 1, characterized in that: The method of determining the background noise of the MHD angular velocity sensor based on the noise voltage power spectrum density of the MHD angular velocity sensor includes: Determining a noise angular velocity power spectral density of the MHD angular velocity sensor based on a noise voltage power spectral density of the MHD angular velocity sensor; Determining a noise angular position power spectral density of the MHD angular velocity sensor based on the noise angular velocity power spectral density of the MHD angular velocity sensor; Determining a first background noise index based on a noise angular velocity power spectrum density and a specified frequency range of the MHD angular velocity sensor; Determining a second background noise index based on the noise angular position power spectrum density of the MHD angular velocity sensor and the specified frequency range; The first background noise index and the second background noise index represent the background noise of the MHD angular velocity sensor.

5. A method for manufacturing a low-noise MHD angular velocity sensor, characterized in that: include: Based on the shape constraint condition, determining the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding and the secondary winding in the MHD angular velocity sensor, respectively, wherein the shape data includes size data, material data and shape data; Based on the shape data of the conductive fluid ring, a parameter value of the conductive equivalent resistance is determined, the shape data includes size data, material data and shape data, and the conductive equivalent resistance represents the equivalent resistance of the conductive fluid ring; Based on the shape data of the upper electrode, a parameter value of an upper equivalent resistor is determined, where the upper equivalent resistor represents an equivalent resistance of the upper electrode on a current path of the MHD angular velocity sensor; Based on the shape data of the lower electrode, a parameter value of the lower equivalent resistance is determined, where the lower equivalent resistance represents the equivalent resistance of the lower electrode in the current path; Based on the shape data of the upper electrode and the conductive fluid ring, the parameter value of the upper contact equivalent resistance is determined, and the upper contact equivalent resistance represents the equivalent resistance of the contact surface between the conductive fluid ring and the upper electrode; Based on the shape data of the lower electrode and the conductive fluid ring, a parameter value of the lower contact equivalent resistance is determined, where the lower contact equivalent resistance represents the equivalent resistance of the contact surface between the conductive fluid ring and the lower electrode; Determine the parameter value of the equivalent resistance of the primary winding based on the shape data of the primary winding; Determining a parameter value of an equivalent resistance of the secondary winding based on the shape data of the secondary winding; Based on the shape data of the magnetic core and the number of turns of the primary winding, the parameter value of the equivalent inductance of the primary winding is determined; Determine the noise angular velocity power spectrum density at the input end of the sensing element based on parameter values ​​of multiple equivalent components and the shape parameters of the magnet, wherein the multiple equivalent components include a conductive equivalent resistance, an upper equivalent resistance, a lower equivalent resistance, an upper contact equivalent resistance, a lower contact equivalent resistance, an equivalent resistance of the primary winding, an equivalent inductance of the primary winding, and an equivalent resistance of the secondary winding; In the case where it is determined that the noise angular velocity power spectrum density at the input end of the sensing element satisfies a first predetermined noise angular velocity power spectrum density condition, determining the noise angular velocity power spectrum density of the MHD angular velocity sensor based on the parameter values ​​of each of the plurality of equivalent components and the turns ratio of the primary winding to the secondary winding; determining a gain of an amplifier when it is determined that the noise angular velocity power spectrum density of the MHD angular velocity sensor satisfies a second predetermined noise angular velocity power spectrum density condition; The MHD angular velocity sensor is manufactured based on the shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding and the secondary winding, the turns ratio, and the gain of the amplifier.

6. The method for manufacturing a low-noise MHD angular velocity sensor according to claim 5, characterized in that: Also includes: When it is determined that the noise angular velocity power spectrum density at the input end of the sensing element does not satisfy a first predetermined noise angular velocity power spectrum density condition, adjusting the shape data of each of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding; The noise angular velocity power spectrum density at the input end of the sensor element is re-determined based on the adjusted shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding and the secondary winding.

7. The method for manufacturing a low-noise MHD angular velocity sensor according to claim 5, characterized in that: Also includes: When it is determined that the noise angular velocity power spectrum density of the MHD angular velocity sensor does not satisfy a second predetermined noise angular velocity power spectrum density condition, adjusting the shape data of each of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding, as well as the turns ratio; The noise angular velocity power spectrum density of the MHD angular velocity sensor is re-determined based on the adjusted shape data of the upper electrode, the lower electrode, the conductive fluid ring, the magnetic core, the magnet, the primary winding, and the secondary winding, as well as the turns ratio.

8. A method for detecting angular velocity, characterized in that: include: Obtain the initial angular velocity detected by the MHD angular velocity sensor; Update the initial angular velocity based on the background noise of the MHD angular velocity sensor to obtain a target angular velocity; The background noise of the MHD angular velocity sensor is determined by using the background noise determination method of a low-noise MHD angular velocity sensor as described in any one of claims 1 to 4.

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