Magnetic sensing unit array and method for measuring planar two-dimensional magnetic field direction

Abstract

The present invention provides a magnetic sensing unit array and a method for measuring the direction of a two-dimensional magnetic field in a plane. The magnetic sensing unit array includes three or more magnetic sensing units with magnetic field sensitive directions. Each of the magnetic sensing units is evenly arranged along the circumferential direction, and the magnetic field sensitive direction of each of the magnetic sensing units is arranged along the radial direction. The advantages of the present invention are: the two-dimensional magnetic field direction can be measured by fitting a cosine function with a period of 2π, which can improve the measurement accuracy of the two-dimensional magnetic field; at the same time, the magnetic sensing unit can still be used normally when some of the magnetic sensing units are damaged, which can improve the robustness of the device.

Description

[Technical field]

[0001] The present invention relates to the technical field of magnetic sensitive sensors, and in particular to an arrangement of a magnetic sensitive sensing unit array, and a method for realizing planar two-dimensional magnetic field direction measurement by utilizing phase information generated by the arrangement of the magnetic sensitive sensing unit array. [Background technology]

[0002] The core magnetosensitive sensing unit of the existing two-dimensional magnetic sensor can be designed based on Hall effect devices, anisotropic magnetoresistive devices, giant magnetoresistive devices or tunnel magnetoresistive devices. Usually, the measurement of two orthogonal direction components of the magnetic field in space is realized based on Hall effect devices, anisotropic magnetoresistive devices, giant magnetoresistive devices and tunnel magnetoresistive devices. It is necessary to use two (groups) of orthogonally arranged core magnetosensitive sensing units (here, these two groups of orthogonally arranged core magnetosensitive sensing units are A and B respectively). The magnetoresistance values ​​of A and B can be used to determine the direction of the two-dimensional magnetic field relative to the orthogonally arranged coordinate system.

[0003] In the above scheme, the stability of the two core magnetic sensing units A and B is crucial. Damage or serious performance degradation of any one of the core magnetic sensing units will significantly affect the implementation and accuracy of the measurement. In other words, the traditional two-dimensional magnetic field direction sensor using two orthogonal core magnetic sensing units A and B has the problems of insufficient device robustness and poor accuracy. In view of the above problems, the inventor of this case conducted an in-depth study on the problem, and thus this case was created. [Summary of the invention]

[0004] The technical problem to be solved by the present invention is to provide a magnetic sensitive sensor unit array and a method for measuring the direction of a two-dimensional magnetic field in a planar manner, so as to solve the technical problems of insufficient device robustness and poor accuracy of the existing two-dimensional magnetic field direction sensor using two groups of orthogonal core magnetic sensitive sensor units.

[0005] The present invention is achieved in that:

[0006] In a first aspect, a magnetic sensitive sensor unit array includes three or more magnetic sensitive sensor units having magnetic field sensitive directions, wherein the magnetic sensitive sensor units are evenly arranged along a circumferential direction, and the magnetic field sensitive directions of the magnetic sensitive sensor units are arranged along a radial direction.

[0007] Furthermore, the magnetic field sensitivity direction of each of the magnetically sensitive sensing units is arranged radially toward the inside of the circumference.

[0008] Furthermore, the magnetic field sensitivity direction of each magnetic sensitive sensing unit is arranged radially toward the outside of the circumference.

[0009] Furthermore, the magnetic sensing unit adopts a magnetic sensor unit with a period of 2π.

[0010] In a second aspect, a method for measuring the direction of a planar two-dimensional magnetic field based on the above-mentioned magnetic sensitive sensor unit array is provided, the method comprising:

[0011] The external magnetic field reference direction of the magnetic sensitive sensing unit array is set, and the magnetic resistance of each magnetic sensitive sensing unit in the magnetic sensitive sensing unit array is measured under the external magnetic field reference direction, and the measured magnetic resistance R (θ) of each magnetic sensitive sensing unit is fitted to obtain a first cosine function curve Among them, θ represents the angle between each magnetic sensing unit and the reference direction, which is the independent variable of the cosine function; represents the phase of the first cosine function curve relative to the cosine function curve cosθ; k represents the coefficient;

[0012] When the direction of the external magnetic field changes, the magnetic resistance of each magnetic sensitive sensing unit in the magnetic sensitive sensing unit array is measured, and the measured magnetic resistance of each magnetic sensitive sensing unit is fitted to obtain a second cosine function curve. in, represents the phase of the second cosine function curve relative to the cosine function curve cosθ;

[0013] The phase of the first cosine function curve Phase with the second cosine function curve For comparison, the phase difference That is, the angle Δα of the changed external magnetic field direction relative to the external magnetic field reference direction, that is,

[0014] Furthermore, after measuring the magnetic resistance of each magnetic sensitive sensing unit in the magnetic sensitive sensing unit array, the magnetic resistance of each magnetic sensitive sensing unit is normalized with an initial state value to obtain a normalized ratio, and the normalized ratio of the magnetic resistance of each magnetic sensitive sensing unit is fitted to obtain a corresponding cosine function curve.

[0015] Furthermore, the method also includes: recording the measurement signals of each magnetic sensitive sensing unit in chronological order, and obtaining the angular velocity of the rotation of the external magnetic field direction by the change of the phase following time.

[0016] By adopting the technical solution of the present invention, at least the following beneficial effects are achieved:

[0017] 1. The direction of the two-dimensional magnetic field can be determined by fitting a cosine function with a period of 2π. Compared with the traditional method of determining the direction of the magnetic field by using orthogonal magnetic sensitive sensing units, the method of fitting a cosine function has higher accuracy and can improve the measurement accuracy of the two-dimensional magnetic field.

[0018] 2. The present invention only needs three or more magnetic sensor units to realize the fitting of the cosine function, and even when some magnetic sensor units are damaged, the cosine function can still be correctly fitted to obtain the measurement result, thus improving the robustness of the device.

[0019] 3. By fitting the normalized ratio of the magnetic resistance of each magnetic sensitive sensor unit to obtain the corresponding cosine function curve, the error influence caused by the performance fluctuation of each independent magnetic sensitive sensor unit can be further reduced, thereby further improving the measurement accuracy.

Brief Description of the Drawings

[0020] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0021] Figure 1 is a schematic diagram of the arrangement of the magnetic sensitive sensor unit array in an embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of a single magnetic sensitive sensing unit in the implementation of the present invention approximating the magnetic resistance to a cosine function with a period of 2π when the external magnetic field changes;

[0023] Figure 3 is a schematic diagram of the external magnetic field reference direction of the magnetic sensitive sensing unit array and the cosine function fitted in the external magnetic field reference direction in an embodiment of the present invention;

[0024] Figure 4 It is a schematic diagram of the magnetic sensitive sensing unit array changing the external magnetic field and the cosine function fitted after the change in the embodiment of the present invention. [Specific implementation method]

[0025] The embodiments of the present invention provide a method for measuring the direction of a two-dimensional magnetic field in a planar manner and thereby solve the technical problems of insufficient device robustness and poor accuracy in an existing two-dimensional magnetic field direction sensor using two groups of orthogonal core magnetic sensor units, thereby achieving a technical effect of improving the robustness of the device and the accuracy of two-dimensional magnetic field measurement.

[0026] The technical solution in the embodiment of the present invention is to solve the above-mentioned problem, and the overall idea is as follows: change the traditional method of orthogonally arranging magnetic sensitive sensing units, and evenly arrange three or more magnetic sensitive sensing units with magnetic field sensitive directions along the circumferential direction, and make the magnetic field sensitive direction of each magnetic sensitive sensing unit set along the radial direction; so that in specific use, the two-dimensional magnetic field direction can be measured by fitting a cosine function with a period of 2π, which can improve the two-dimensional magnetic field measurement accuracy; at the same time, even if some magnetic sensitive sensing units are damaged, they can still be used normally, which can improve the robustness of the device.

[0027] In order to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] Embodiment 1

[0029] See also Figure 1 and Figure 2 As shown, the present invention provides a magnetic sensitive sensor unit array, which includes three or more magnetic sensitive sensor units 1 having a magnetic field sensitive direction (denoted as e0), each of the magnetic sensitive sensor units 1 is evenly arranged along the circumferential direction, and the magnetic field sensitive direction e0 of each of the magnetic sensitive sensor units 1 is arranged along the radial direction.

[0030] Please refer to Figure 2 As shown, the magnetic sensitive sensing unit 1 used in the present invention, when the angle between the external magnetic field H and the magnetic field sensitive direction e0 changes, according to the giant magnetoresistance effect or the tunneling magnetoresistance effect, in the linear response region, the magnetoresistance R(θ) of the magnetic sensitive sensing unit 1 can be approximated as a cosine function with a period of 2π.

[0031] The present invention arranges three or more magnetic sensing units 1 having a magnetic field sensitive direction e0 evenly along the circumferential direction, and sets the magnetic field sensitive direction e0 of each magnetic sensing unit 1 along the radial direction, and the magnetic resistance R(θ) of each magnetic sensing unit 1 can be approximated as a cosine function with a period of 2π. When the direction of the external magnetic field changes, the magnetic resistance R(θ) of each magnetic sensing unit 1 can change according to the physical effect of its magnetic sensing. Therefore, the technical solution of the present invention has at least the following beneficial effects:

[0032] 1. The direction of the two-dimensional magnetic field can be determined by fitting a cosine function with a period of 2π. Compared with the traditional method of determining the direction of the magnetic field by using orthogonal magnetic sensitive sensing units, the method of fitting a cosine function has higher accuracy and can improve the measurement accuracy of the two-dimensional magnetic field.

[0033] 2. The present invention only needs three or more magnetic sensor units 1 to achieve the fitting of the cosine function, and even if some of the magnetic sensor units 1 are damaged, the cosine function can still be correctly fitted to obtain the measurement result, thereby improving the robustness of the device.

[0034] As a specific implementation of the present invention, the magnetic field sensitive direction e0 of each magnetic sensitive sensing unit 1 is arranged along the radial direction toward the inside of the circumference.

[0035] As another specific implementation of the present invention, the magnetic field sensitive direction e0 of each magnetic sensitive sensing unit 1 is arranged radially toward the outside of the circumference.

[0036] In some embodiments of the present invention, the magnetic sensor unit 1 uses a magnetic sensor unit with a 2π period, specifically a magnetic sensor unit with a 2π period in the magnetic field direction in a given plane, and the given plane is the plane where the magnetic sensor unit array is located; for example, using any one of giant magnetoresistance devices and tunnel magnetoresistance devices as the magnetic sensor unit 1 in the magnetic sensor unit 1 array can achieve two-dimensional magnetic field measurement, so it has good applicability. Of course, the present invention is not limited to this, and other magnetic sensor units with a 2π period can also be used in specific implementation.

[0037] The following is a further description of the magnetic sensing unit array of the present invention in conjunction with a specific example: Figure 1 As shown, in this specific example, the magnetic sensing unit array includes 8 magnetic sensing units 1, No. 1 to No. 8, which are evenly arranged in the circumferential direction at equal intervals, and the magnetic field sensitive directions e0 of the 8 magnetic sensing units 1 are all set radially toward the outside of the circumference. During the use of the magnetic sensing unit 1 array, even if all the magnetic sensing units 1 of No. 4 to No. 8 are damaged (the damage rate reaches 62.5%), the magnetic field direction can still be determined by signal fitting of the three magnetic sensing units 1 of No. 1 to No. 3, so it has good robustness.

[0038] Embodiment 2

[0039] Please refer to Figures 1 to 4 As shown, the present invention provides a method for measuring the direction of a planar two-dimensional magnetic field based on a magnetic sensitive sensing unit array, wherein the specific structure of the magnetic sensitive sensing unit array is described in detail in the first embodiment, which will not be described in detail here;

[0040] The method comprises:

[0041] The external magnetic field reference direction of the magnetic sensitive sensing unit array is set, and the magnetic resistance of each magnetic sensitive sensing unit 1 in the magnetic sensitive sensing unit array is measured under the external magnetic field reference direction, and the measured magnetic resistance R (θ) of each magnetic sensitive sensing unit 1 is fitted to obtain the first cosine function curve with a period of 2π Wherein, θ represents the angle between each magnetic sensing unit 1 and the reference direction, and is the independent variable of the cosine function; represents the phase of the first cosine function curve relative to the cosine function curve cosθ; k represents the coefficient, that is, the coefficient when it is not normalized; the first cosine function curve Used to serve as a reference;

[0042] When the direction of the external magnetic field changes, the magnetoresistance of each magnetoresistance sensor unit in the magnetoresistance sensor array is measured, and the magnetoresistance of each magnetoresistance sensor unit is fitted to obtain a second cosine function curve with a period of 2π. in, represents the phase of the second cosine function curve relative to the cosine function curve cosθ;

[0043] The phase of the first cosine function curve Phase with the second cosine function curve For comparison, the phase difference That is, the angle Δα of the changed external magnetic field direction relative to the external magnetic field reference direction, that is,

[0044] Since in the technical solution of the present invention, the direction of the two-dimensional magnetic field is determined by fitting a cosine function with a period of 2π, compared with the traditional method of determining the direction of the magnetic field by using orthogonally arranged magnetic sensitive sensing units, the present invention has higher accuracy through cosine function fitting, and can improve the measurement accuracy of the two-dimensional magnetic field.

[0045] In some embodiments of the present invention, after measuring the magnetic resistance R (θ) of each magnetic sensitive sensing unit 1 in the magnetic sensitive sensing unit array, the magnetic resistance R (θ) of each magnetic sensitive sensing unit 1 is normalized with an initial state value to obtain a normalized ratio, and the normalized ratio of the magnetic resistance R (θ) of each magnetic sensitive sensing unit 1 is fitted to obtain a corresponding cosine function curve; for example, in the reference direction of the magnetic field, the normalized ratio of the magnetic resistance R (θ) of each magnetic sensitive sensing unit 1 is fitted to obtain a first cosine function curve Because the magnetoresistance R(θ) is normalized, the coefficient k is 1; for example, when the direction of the external magnetic field changes, the normalized ratio of the magnetoresistance R(θ) of each magnetic sensitive sensing unit 1 is fitted to obtain the second cosine function curve Because the magnetoresistance R(θ) is normalized, the coefficient k is 1. The present invention can further reduce the error effect caused by the performance fluctuation of each independent magnetoresistance R(θ) by fitting the normalized ratio of each magnetoresistance R(θ) of each magnetoresistance sensing unit 1 to obtain the corresponding cosine function curve, thereby further improving the measurement accuracy.

[0046] In some embodiments of the present invention, the method also includes: recording the measurement signals of each magnetic sensitive sensing unit 1 (i.e., the measurement signals of the magnetic resistance of the magnetic sensitive sensing unit 1) in chronological order, and obtaining the angular velocity of the rotation in the direction of the external magnetic field by the change of the phase following time; this is a magnetic sensitive angular velocity meter solution that does not require additional moving parts, that is, the measurement of magnetic sensitive angular velocity can also be achieved through the technical solution of the present invention, and no additional moving parts need to be set up, which is conducive to reducing the overall cost of the device.

[0047] The method of the present invention is further described below in conjunction with specific examples:

[0048] In this specific example, the magnetic sensing unit array includes 8 magnetic sensing units 1, No. 1 to No. 8, which are evenly arranged in the circumferential direction with equal intervals, and the magnetic field sensitive directions e0 of the 8 magnetic sensing units 1 are all set radially toward the outside of the circumference.

[0049] In the reference direction of the external magnetic field, eight magnetic sensing units 1 are mapped according to the numbers No. 1 to No. 8, as shown in FIG. Figure 3 As shown; when the direction of the external magnetic field changes Δθ, the eight magnetic sensing units 1 are plotted according to the numbers No.1 to No.8, as shown Figure 4 As shown; through Figure 3 and Figure 4 By comparison, it can be found that: when the direction of the external magnetic field changes by Δθ, the magnetic resistance R(θ) of each magnetic sensitive sensing unit 1 can be obtained by fitting the magnetic resistance R(θ) of each magnetic sensitive sensing unit 1 under the external magnetic field reference direction, and the cosine function undergoes a phase shift of Δφ; therefore, when the direction of the external magnetic field changes, it is only necessary to measure the magnetic resistance R(θ) of each magnetic sensitive sensing unit 1 and perform cosine function fitting, and then compare the phase of the fitted cosine function with the phase of the cosine function under the external magnetic field reference direction (in this specific example, the external magnetic field reference direction is the x direction), so as to obtain the angle of the changed external magnetic field direction relative to the external magnetic field reference direction.

[0050] In the actual application of the present invention, the magnetoresistance measurement (collection) of each of the above-mentioned magnetoresistance sensing units 1 can be realized once by the peripheral circuit of the magnetoresistance sensing unit; the fitting and angle analysis based on the magnetoresistance signal can be directly completed by a single chip microcomputer or an integrated embedded system to achieve miniaturization.

[0051] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for measuring the direction of a two-dimensional magnetic field of a magnetic sensitive sensor unit array, characterized in that: The magnetic sensitive sensing unit array includes three or more magnetic sensitive sensing units having magnetic field sensitive directions, each of the magnetic sensitive sensing units is evenly arranged along the circumferential direction, and the magnetic field sensitive direction of each of the magnetic sensitive sensing units is arranged along the radial direction; the method includes: The external magnetic field reference direction of the magnetic sensitive sensing unit array is set, and the magnetic resistance of each magnetic sensitive sensing unit in the magnetic sensitive sensing unit array is measured under the external magnetic field reference direction, and the measured magnetic resistance R(θ) of each magnetic sensitive sensing unit is fitted to obtain a first cosine function curve kcos(θ+φ1), wherein θ represents the angle between each magnetic sensitive sensing unit and the reference direction, which is the independent variable of the cosine function; φ1 represents the phase of the first cosine function curve relative to the cosine function curve cosθ; k represents the coefficient; When the direction of the external magnetic field changes, the magnetoresistance of each magnetoresistance sensing unit in the magnetoresistance sensing unit array is measured, and the magnetoresistance of each magnetoresistance sensing unit is fitted to obtain a second cosine function curve kcos(θ+φ2), wherein φ2 represents the phase of the second cosine function curve relative to the cosine function curve cosθ; The phase φ1 of the first cosine function curve is compared with the phase φ2 of the second cosine function curve. The phase difference Δφ=φ2-φ1 is the angle Δα of the changed external magnetic field direction relative to the external magnetic field reference direction, that is, Δα=Δφ.

2. The method according to claim 1, characterized in that: The magnetic field sensitive direction of each magnetic sensitive sensing unit is arranged along the radial direction toward the inside of the circumference.

3. The method according to claim 1, characterized in that: The magnetic field sensitive direction of each magnetic sensitive sensing unit is arranged radially toward the outside of the circumference.

4. The method according to claim 1, characterized in that: The magnetic sensing unit adopts a magnetic sensor unit with a 2π period.

5. The method according to claim 1, characterized in that: After measuring the magnetoresistance of each magnetoresistance sensor unit in the magnetoresistance sensor unit array, the magnetoresistance of each magnetoresistance sensor unit is normalized with an initial state value to obtain a normalized ratio, and the normalized ratio of the magnetoresistance of each magnetoresistance sensor unit is fitted to obtain a corresponding cosine function curve.

6. The method according to claim 1, characterized in that: The method further comprises: recording the measurement signals of each magnetic sensitive sensing unit in chronological order, and obtaining the angular velocity of the rotation of the external magnetic field direction by the change of the phase following time.

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