A weak magnetic field measuring device and a measuring method thereof

Abstract

The present invention discloses a weak magnetic field measuring device and a measuring method thereof. The weak magnetic field measuring device includes a lifting platform, a horizontal movable platform and a suspension bracket provided on the lifting platform, the suspension bracket being located on one side of the horizontal movable platform, a fixed bracket provided on the horizontal movable platform, and a soft magnetic body provided at the end of the fixed bracket; a magnet located on one side of the soft magnetic body is suspended on the suspension bracket; the weak magnetic field measuring device places the soft magnetic body in the magnetic field to be measured, so that it generates an amplified magnetic field around it, moves the soft magnetic body close to the adsorption magnet body, causes the magnet body to be adsorbed to the soft magnetic body, and obtains a critical distance for adsorption to occur. The magnetic field strength of the corresponding magnetic field to be measured can be obtained by using the critical distance and the distance-magnetic field strength quadratic function expression, and then the magnetic field direction of the magnetic field to be measured is obtained using the markings on the magnet body.

Description

Technical Field

[0001] The present invention relates to the technical field of weak magnetic field measurement, and in particular to a weak magnetic field measurement device and a measurement method thereof. Background Art

[0002] As a key technology in scientific research and industrial applications, magnetic field measurement is of undeniable importance. From fundamental physics research to practical applications such as the optimization of electrical equipment, innovation in medical devices, breakthroughs in aerospace technology, and the development of wireless energy transfer, magnetic field measurement technology plays a vital role. Traditional magnetic field measurement instruments, such as fluxgate magnetometers and magnetoresistive magnetometers, while excellent at measuring strong magnetic fields with high accuracy and stability, often struggle with weak magnetic field measurements.

[0003] The main challenges in measuring weak magnetic fields come from two aspects: first, environmental noise interference, including background noise from the Earth's magnetic field and electromagnetic interference, which can mask weak magnetic field signals and make accurate measurement difficult; second, limitations in signal processing technology. How to effectively extract and amplify weak magnetic field signals in a complex noise background is a major problem facing current technology. Therefore, the development of a weak magnetic field measurement device and measurement method is particularly important. Summary of the Invention

[0004] In response to the above problems in the prior art, the present invention provides a weak magnetic field measuring device and a measuring method thereof, which solve the problem of low measurement accuracy of traditional magnetic field measuring instruments when measuring weak magnetic fields.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0006] A weak magnetic field measuring device is provided, which includes a lifting platform, a horizontal movable platform and a suspension bracket provided on the lifting platform, the suspension bracket being located on one side of the horizontal movable platform, a fixed bracket provided on the horizontal movable platform, a soft magnet provided at the end of the fixed bracket; a magnet located on one side of the soft magnet is suspended on the suspension bracket. The soft magnet will linearly amplify the external magnetic field within a certain range, making it easy to measure weak magnetic fields. The weak magnetic field measuring device places the soft magnet in the magnetic field to be measured, so that it generates an amplified magnetic field around it, moves the soft magnet close to the magnet, causes the magnet to be adsorbed on the soft magnet, and obtains the critical distance for adsorption. The magnetic field strength of the corresponding magnetic field to be measured can be obtained by the critical distance and the quadratic function expression of distance-magnetic field strength, and then the magnetic field direction of the magnetic field to be measured can be obtained using the mark on the magnet.

[0007] Furthermore, the horizontal movable platform includes a fixed platform and a movable platform; the movable platform is slidably connected to the fixed platform, and a screw propeller is provided on one side of the movable platform, and the screw propeller is used to drive the movable platform to move horizontally;

[0008] The suspension bracket is a cantilever beam structure, one side of the suspension bracket is fixedly connected to the fixed platform, and the other side is provided with a suspension member, on which a magnet is suspended through a nylon line;

[0009] One end of the fixed bracket is fixedly connected to the upper end surface of the mobile platform, and the other end is provided with a mounting groove in which a soft magnetic body is fixed; the mobile platform drives the fixed bracket and the soft magnetic body to move toward the magnet body.

[0010] Furthermore, the magnet body includes an iron needle fixedly connected to the bottom of the nylon line, and a magnet is attached to each side of the iron needle. The two magnets can be used to determine the magnetic field direction of the magnetic field to be measured.

[0011] The present invention also provides a measurement method for a weak magnetic field measurement device, characterized by comprising:

[0012] Step 1: Place the soft magnetic material and the magnetic body into the magnetic field to be measured;

[0013] Step 2: Observe the rotation direction of the magnet to determine the magnetic field direction of the magnetic field to be measured;

[0014] Step 3: Rotate the screw propeller to drive the horizontal moving platform to push the soft magnetic body close to the magnet body;

[0015] Step 4: When the magnet is attracted by the soft magnetic body, stop rotating the propeller and read the distance data displayed by the propeller;

[0016] Step 5: Rotate the screw propeller to move the soft magnet backward to separate the soft magnet from the magnet until the magnet returns to a stationary state;

[0017] Step 6: Repeat steps 3 to 5 multiple times and then stop, obtain the distance data displayed by multiple propellers, and calculate the average value of the distance data of the multiple propellers;

[0018] Step 7: Substitute the average value into the fitted distance-magnetic field strength quadratic function expression to calculate the magnetic field strength of the magnetic field to be measured.

[0019] Furthermore, in step 7, the fitted distance-magnetic field strength quadratic function expression includes

[0020] y=0.0104x 2 -0.2221x+1.3832

[0021] R 2 =0.9997 (1)

[0022] y=0.011x 2 -0.2284x+1.3737

[0023] R 2 =0.9998 (2)

[0024] Among them, the distance-magnetic field strength quadratic function expression (1) refers to the expression of the magnetic field strength of the magnetic field to be measured on the N-pole surface and the distance from the propeller; the distance-magnetic field strength quadratic function expression (2) refers to the expression of the distance between the magnetic field to be measured on the S-pole surface and the propeller; in the distance-magnetic field strength quadratic function expressions (1) and (2), y represents the magnetic field strength of the magnetic field to be measured, x represents the distance displayed by the propeller, and R 2 Expressed as the coefficient of determination.

[0025] Furthermore, the method for obtaining the distance-magnetic field strength quadratic function expressions (1) and (2) includes:

[0026] Soft magnets will linearly amplify the magnetic field to be measured within a certain range: the relationship between the demagnetization field and the original magnetic field is linearly amplified as follows:

[0027] H=nB (3)

[0028] Wherein, H is the magnetic field strength of the soft magnetic body; n is a constant; B is the magnetic field strength of the magnetic field to be measured;

[0029] The magnet body will swing under the attraction of the soft magnet, and will be adsorbed onto the soft magnet when it exceeds the critical distance. In the critical state, the force T acting on the nylon line is orthogonally decomposed along the horizontal and vertical directions as follows:

[0030] F H cosβ=Tsinα (4)

[0031] F H sinβ+Tcosα=G (5)

[0032] Among them, F H is the magnetic force between the soft magnetic body and the magnet, G is the gravity of the magnet, α is the deflection angle of the magnet under the critical state, and β is the angle between the magnet and the soft magnetic body in the horizontal direction under the critical state;

[0033] Substituting formula (4) into formula (5), we have:

[0034] F H (sinβ+cosβcotα)=G#(6)

[0035] The relationship between the distance L between the soft magnetic body and the magnetic body and the horizontal distance d between the soft magnetic body and the magnetic body is:

[0036]

[0037] The mutual magnetic force F between the two H satisfy:

[0038]

[0039] Where k is the proportionality coefficient, m1 is the magnetic pole strength of the soft magnetic body, and m2 is the magnetic pole strength of the magnet body.

[0040] From formulas (6), (7), and (8), we can get:

[0041]

[0042] During the experiment, the magnet is slightly lower than the soft magnet to facilitate contact between the two. In fact, the angle β is often very small. At this time, sinβ is approximately 0 and cosβ is approximately 1. The above formula (9) becomes:

[0043]

[0044] The magnetic pole strength generated by the magnetic charge is proportional to the magnetic field strength. Let μ be the proportional coefficient, then:

[0045] m1=μH#(11)

[0046] From formulas (3)(10)(11), we can get:

[0047]

[0048] There is a constant difference between the distance x and d shown by the propeller. This constant can be positive or negative. Let this constant be a, then:

[0049]

[0050] make

[0051]

[0052] Then we have:

[0053] B=C(x+a) 2 =C(x 2 +2ax+a 2 )#(15)

[0054] The distance x displayed by the propeller is recorded, and the magnetic field is recorded using a Tesla meter. The distance and the magnetic field correspond one to one, and a fitting curve of the distance and the magnetic field strength is drawn. Based on the fitting curve, the quadratic function expressions (1) and (2) of the distance-magnetic field strength are fitted.

[0055] The beneficial effects of the present invention are as follows: a weak magnetic field measurement device and method are provided, wherein a soft magnetic object is placed in a magnetic field to be measured, generating an amplified magnetic field around it. The soft magnetic object is then moved close to an adsorbing magnet, causing the magnet to adsorb to the soft magnetic object, and a critical distance at which adsorption occurs is determined. The critical distance and the quadratic function expression of distance-magnetic field strength are used to determine the magnetic field strength of the corresponding magnetic field to be measured. The magnetic field direction of the magnetic field to be measured is then determined using markings on the magnet. This solves the problem of low measurement accuracy of traditional magnetic field measuring instruments when measuring weak magnetic fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the three-dimensional structure of a weak magnetic field measurement device.

[0057] Figures 2 to 4 They are the principle diagrams of the weak magnetic field measurement device.

[0058] Figure 5 It is a fitting curve diagram of the magnetic field intensity of the magnetic field to be measured on the N-pole surface and the distance from the propeller.

[0059] Figure 6 It is a fitting curve diagram of the magnetic field intensity of the magnetic field to be measured on the S pole surface and the distance from the propeller.

[0060] Among them, 1. Lifting platform; 2. Horizontal moving platform; 201. Fixed platform; 202. Moving platform; 3. Suspension bracket; 4. Fixed bracket; 5. Soft magnet; 6. Magnet; 7. Screw propeller; 8. Nylon line. DETAILED DESCRIPTION

[0061] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0062] like Figure 1 As shown, the present invention provides a weak magnetic field measurement device, which includes a lifting platform 1, a horizontal moving platform 2 and a suspension bracket 3 are provided on the lifting platform 1, the suspension bracket 3 is located on one side of the horizontal moving platform 2, a fixed bracket 4 is provided on the horizontal moving platform 2, and a soft magnetic body 5 is provided at the end of the fixed bracket 4; a magnet 6 located on one side of the soft magnetic body 5 is suspended on the suspension bracket 3. The soft magnetic body 5 will linearly amplify the external magnetic field within a certain range, which is convenient for realizing weak magnetic field measurement. Figure 2As shown, the weak magnetic field measurement device places a soft magnetic object 5 in the magnetic field to be measured, generating an amplified magnetic field around it. The soft magnetic object 5 is then moved close to a magnet 6, causing the magnet 6 to adhere to the soft magnetic object 5. The critical distance at which this adhesion occurs is determined. The critical distance and the quadratic function expression of distance-magnetic field strength are used to determine the magnetic field strength of the corresponding magnetic field to be measured. The markings on the magnet 6 are then used to determine the magnetic field direction of the magnetic field to be measured.

[0063] The horizontal movable platform 2 includes a fixed platform 201 and a movable platform 202; the movable platform 202 is slidingly connected to the fixed platform 201, and a screw propeller 7 is provided on one side of the movable platform 202, which is used to drive the movable platform 202 to move horizontally; the suspension bracket 3 is a cantilever beam structure, one side of the suspension bracket 3 is fixedly connected to the fixed platform 201, and the other side is provided with a suspension member, and a magnet body 6 is suspended on the suspension member through a nylon line 8; one end of the fixed bracket 4 is fixedly connected to the upper end surface of the movable platform 202, and the other end is provided with an installation groove, in which a soft magnetic body 5 is fixed; the movable platform 202 drives the fixed bracket 4 and the soft magnetic body 5 to move toward the magnet body 6.

[0064] The magnet body 6 comprises an iron pin fixedly connected to the bottom of the nylon line 8, and a magnet is respectively attached to both sides of the iron pin. The two magnets can be used to determine the magnetic field direction of the magnetic field to be measured.

[0065] The present invention also provides a measurement method for a weak magnetic field measurement device, characterized by comprising:

[0066] Step 1: Place the soft magnetic body 5 and the magnet body 6 into the magnetic field to be measured;

[0067] Step 2: Observe the rotation direction of the magnet 6 to determine the magnetic field direction of the magnetic field to be measured;

[0068] Step 3: Rotate the screw propeller 7 to drive the horizontal moving platform 2 to push the soft magnetic body 5 close to the magnet body 6;

[0069] Step 4: When the magnet 6 is attracted by the soft magnetic body 5, the screw propeller 7 stops rotating and the distance data displayed by the screw propeller 7 is read;

[0070] Step 5: Rotate the screw propeller 7 to move the soft magnetic body 5 backward to separate the soft magnetic body 5 from the magnet body 6 until the magnet body 6 returns to a stationary state;

[0071] Step 6: Repeat steps 3 to 5 multiple times and then stop, obtain the distance data displayed by multiple propellers 7, and calculate the average value of the distance data of multiple propellers 7;

[0072] Step 7: Substitute the average value into the fitted distance-magnetic field strength quadratic function expression to calculate the magnetic field strength of the magnetic field to be measured.

[0073] Furthermore, if Figure 5 and Figure 6 As shown in step 7, the fitted distance-magnetic field strength quadratic function expression includes

[0074] y=0.0104x 2 -0.2221x+1.3832

[0075] R 2 =0.9997 (1)

[0076] y=0.011x 2 -0.2284x+1.3737

[0077] R 2 =0.9998 (2)

[0078] The distance-magnetic field strength quadratic function expression (1) refers to the expression of the magnetic field strength of the magnetic field to be measured on the N-pole surface and the distance from the propeller 7; the distance-magnetic field strength quadratic function expression (2) refers to the expression of the distance from the magnetic field to be measured on the S-pole surface and the propeller 7; in the distance-magnetic field strength quadratic function expressions (1) and (2), y represents the magnetic field strength of the magnetic field to be measured, x represents the distance displayed by the propeller 7, and R 2 Expressed as the coefficient of determination.

[0079] Furthermore, the method for obtaining the distance-magnetic field strength quadratic function expressions (1) and (2) includes:

[0080] like Figures 2 to 4 As shown, the soft magnetic body 5 will linearly amplify the magnetic field to be measured within a certain range: the relationship between the demagnetization field and the original magnetic field is linearly amplified as follows:

[0081] H=nB (3)

[0082] Wherein, H is the magnetic field strength of the soft magnetic body 5; n is a constant; B is the magnetic field strength of the magnetic field to be measured;

[0083] The magnet 6 will swing under the attraction of the soft magnetic body 5. When the distance exceeds the critical distance, the magnet 6 will be adsorbed on the soft magnetic body 5. In the critical state, the force T acting on the nylon wire 8 is orthogonally decomposed along the horizontal and vertical directions as follows:

[0084] F t cosβ=Tsinα (4)

[0085] F H sinβ+Tcosα=G (5)

[0086] Among them, F His the magnetic force between the soft magnetic body 5 and the magnet body 6, G is the gravity of the magnet body 6, α is the deflection angle of the magnet body 6 in the critical state, and β is the angle between the magnet body 6 and the soft magnetic body 5 in the horizontal direction in the critical state;

[0087] Substituting formula (4) into formula (5), we have:

[0088] F H (sinβ+cosβcotα)=G#(6)

[0089] The relationship between the distance L between the soft magnetic body 5 and the magnet body 6 and the horizontal distance d between the soft magnetic body 5 and the magnet body 6 is:

[0090]

[0091] The mutual magnetic force F between the two H satisfy:

[0092]

[0093] Wherein k is the proportional coefficient, m1 is the magnetic pole strength of the soft magnetic body 5, and m2 is the magnetic pole strength of the magnet body 6.

[0094] From formulas (6), (7), and (8), we can get:

[0095]

[0096] During the experiment, the magnet 6 is slightly lower than the soft magnetic body 5 in order to facilitate the contact between the two. In fact, the angle β is often very small. At this time, sinβ is approximately 0 and cosβ is approximately 1. The above formula (9) becomes:

[0097]

[0098] The magnetic pole strength generated by the magnetic charge is proportional to the magnetic field strength. Let μ be the proportional coefficient, then:

[0099] m1=μH#(11)

[0100] From formulas (3)(10)(11), we can get:

[0101]

[0102] There is a constant difference between the distance x and d displayed by the propeller 7. The constant can be positive or negative. Let the constant be a, then:

[0103]

[0104] make

[0105]

[0106] Then we have:

[0107] B=C(x+a) 2 =C(x 2 +2ax+a 2 )#(15)

[0108] like Figure 5 and Figure 6 As shown, the distance x displayed by the propeller 7 is recorded, and the magnetic field is recorded using a Tesla meter. The distance and the magnetic field correspond one to one, and a fitting curve of the distance and the magnetic field strength is drawn. Based on the fitting curve, the quadratic function expressions (1) and (2) of the distance-magnetic field strength are fitted.

[0109] In summary, the present invention provides a weak magnetic field measurement device and method. This device and method employ a method of placing a soft magnetic object 5 within a magnetic field to be measured, generating an amplified magnetic field around it. The soft magnetic object 5 is then moved close to a magnet 6, causing the magnet 6 to adhere to the soft magnetic object 5. The critical distance at which this adhesion occurs is determined. The critical distance and the quadratic function expression of distance-magnetic field strength are used to determine the magnetic field strength of the corresponding magnetic field to be measured. The markings on the magnet 6 are then used to determine the magnetic field direction of the magnetic field to be measured. This method addresses the low measurement accuracy of traditional magnetic field measuring instruments when measuring weak magnetic fields.

Claims

1. A weak magnetic field measuring device, characterized in that: The invention comprises a lifting platform, wherein the lifting platform is provided with a horizontal movable platform and a suspension bracket, wherein the suspension bracket is located on one side of the horizontal movable platform, a fixed bracket is provided on the horizontal movable platform, and a soft magnetic body is provided at the end of the fixed bracket; a magnet body located on one side of the soft magnetic body is suspended on the suspension bracket; The horizontal movable platform includes a fixed platform and a movable platform; the movable platform is slidably connected to the fixed platform, and a screw propeller is provided on one side of the movable platform, and the screw propeller is used to drive the movable platform to move horizontally; The suspension bracket is a cantilever beam structure, one side of the suspension bracket is fixedly connected to the fixed platform, and the other side is provided with a suspension member, and the magnet body is suspended on the suspension member through a nylon line; One end of the fixed bracket is fixedly connected to the upper end surface of the movable platform, and the other end is provided with a mounting groove, in which the soft magnetic body is fixed; the movable platform drives the fixed bracket and the soft magnetic body to move toward the magnet body; The measurement method of the weak magnetic field measurement device includes: Step 1: Place the soft magnetic material and the magnetic body into the magnetic field to be measured; Step 2: Observe the rotation direction of the magnet to determine the magnetic field direction of the magnetic field to be measured; Step 3: Rotate the screw propeller to drive the horizontal moving platform to push the soft magnetic body close to the magnet body; Step 4: When the magnet is attracted by the soft magnetic body, stop rotating the propeller and read the distance data displayed by the propeller; Step 5: Rotate the screw propeller to move the soft magnet backward to separate the soft magnet from the magnet until the magnet returns to a stationary state; Step 6: Repeat steps 3 to 5 multiple times and then stop, obtain the distance data displayed by multiple propellers, and calculate the average value of the distance data of the multiple propellers; Step 7: Substitute the average value into the fitted distance-magnetic field strength quadratic function expression to calculate the magnetic field strength of the magnetic field to be measured. The fitted distance-magnetic field strength quadratic function expression includes: Among them, the distance-magnetic field strength quadratic function expression (1) refers to the expression of the magnetic field strength of the magnetic field to be measured on the N-pole surface and the distance from the propeller; the distance-magnetic field strength quadratic function expression (2) refers to the expression of the distance between the magnetic field to be measured on the S-pole surface and the propeller; in the distance-magnetic field strength quadratic function expressions (1) and (2), y Indicates the magnetic field strength of the magnetic field to be measured, x Indicates the distance displayed for the propeller, Expressed as the coefficient of determination.

2. The weak magnetic field measuring device according to claim 1, characterized in that: The magnet body comprises an iron needle fixedly connected to the bottom of the nylon line, and a magnet is respectively attached to both sides of the iron needle.

3. The weak magnetic field measuring device according to claim 1, characterized in that: Methods for obtaining distance-magnetic field strength quadratic function expressions (1) and (2) include: Soft magnets will linearly amplify the magnetic field to be measured within a certain range: the relationship between the demagnetization field and the original magnetic field is linearly amplified as follows: in, is the magnetic field strength of the soft magnet; is a constant; is the magnetic field strength of the magnetic field to be measured; The magnet body will swing under the attraction of the soft magnet, and will be adsorbed onto the soft magnet when it exceeds the critical distance. In the critical state, the force T acting on the nylon line is orthogonally decomposed along the horizontal and vertical directions as follows: in, It is the magnetic force between the soft magnetic body and the magnetic body. is the gravity of the magnet, is the deflection angle of the magnet in the critical state, It is the angle between the magnet and the soft magnet in the horizontal direction under the critical state; Substituting formula (4) into formula (5), we have: The distance between the soft magnetic body and the magnetic body Horizontal distance from soft magnetic body and magnetic body The relationships are: The mutual magnetic force between the two satisfy: in is the proportionality coefficient, is the magnetic pole strength of the soft magnet, is the magnetic pole strength of the magnet; From formulas (6), (7), and (8), we can get: During the experiment, the magnet is slightly lower than the soft magnet to facilitate the contact between the two. In fact, the β angle is often very small. Approximately 0 and is approximately 1, and the above formula (9) becomes: The magnetic pole strength generated by the magnetic charge is proportional to the magnetic field strength. μ is the proportional coefficient, then: From formula (3)(10)(11), we can get: The propeller shows the distance x and d There is a constant gap between them, which can be positive or negative. Let the constant be a , then: make Then we have: Record the distance displayed by the propeller x , use a Tesla meter to record the magnetic field, the distance and the magnetic field correspond one to one, draw a fitting curve of distance and magnetic field strength, and fit the distance-magnetic field strength quadratic function expressions (1) and (2) based on the fitting curve.

4. A measurement method based on the weak magnetic field measurement device according to any one of claims 1 to 3, characterized in that: include: Step 1: Place the soft magnetic material and the magnetic body into the magnetic field to be measured; Step 2: Observe the rotation direction of the magnet to determine the magnetic field direction of the magnetic field to be measured; Step 3: Rotate the screw propeller to drive the horizontal moving platform to push the soft magnetic body close to the magnet body; Step 4: When the magnet is attracted by the soft magnetic body, stop rotating the propeller and read the distance data displayed by the propeller; Step 5: Rotate the screw propeller to move the soft magnet backward to separate the soft magnet from the magnet until the magnet returns to a stationary state; Step 6: Repeat steps 3 to 5 multiple times and then stop, obtain the distance data displayed by multiple propellers, and calculate the average value of the distance data of the multiple propellers; Step 7: Substitute the average value into the fitted distance-magnetic field strength quadratic function expression to calculate the magnetic field strength of the magnetic field to be measured.

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