Weak magnetic field measuring device and measuring method thereof

Abstract

The invention discloses a weak magnetic field measuring device and a measuring method thereof. The weak magnetic field measuring device comprises a lifting platform, a horizontal moving platform and a suspension support are arranged on the lifting platform, the suspension support is located on one side of the horizontal moving platform, a fixed support is arranged on the horizontal moving platform, and a soft magnet is arranged at the end of the fixed support; a magnet body located on one side of the soft magnet is hung on the hanging support. According to the weak magnetic field measuring device, a soft magnet is arranged in a magnetic field to be measured, an amplified magnetic field is generated around the soft magnet, the soft magnet is moved to approach and attract a magnet body, the magnet body is attracted to the soft magnet, and the critical distance of attraction is obtained. The magnetic field intensity of the corresponding to-be-measured magnetic field can be obtained through the critical distance and the distance-magnetic field intensity quadratic function expression, and then the magnetic field direction of the to-be-measured magnetic field is obtained through the mark 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 technical means in scientific research and industrial applications, the importance of magnetic field measurement is self-evident. From basic physical research to practical applications such as optimization of electrical equipment, innovation of medical equipment, breakthroughs in aerospace technology, and the development of wireless energy transfer technology, magnetic field measurement technology plays a vital role. Traditional magnetic field measurement instruments, such as fluxgate magnetometers and magnetoresistive magnetometers, perform well in strong magnetic field measurements with high accuracy and stability, but their performance is often limited when facing weak magnetic field measurements.

[0003] The main challenges of weak magnetic field measurement come from two aspects: one is the interference of environmental noise, including the background noise of the earth's magnetic field and electromagnetic interference, which will mask the weak magnetic field signal and make accurate measurement difficult; the other is the limitation of signal processing technology. How to effectively extract and amplify weak magnetic field signals under complex noise background is a major problem facing current technology. Therefore, it is particularly important to develop a weak magnetic field measurement device and its measurement method. Summary of the invention

[0004] In view of 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 when traditional magnetic field measuring instruments measure 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 moving platform and a suspension bracket are arranged on the lifting platform, the suspension bracket is located on one side of the horizontal moving platform, a fixed bracket is arranged on the horizontal moving platform, a soft magnet is arranged 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, which is convenient for realizing weak magnetic field measurement. The weak magnetic field measuring device sets 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 adsorbed magnet, makes the magnet adsorb to 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 is obtained by using the mark on the magnet.

[0007] Furthermore, the horizontal moving platform includes a fixed platform and a moving platform; the moving platform is slidably connected to the fixed platform, and a screw propeller is provided on one side of the moving platform, and the screw propeller is used to drive the moving 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 body 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 respectively attached to both sides 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 of a weak magnetic field measurement device, characterized by comprising:

[0012] Step 1, placing the soft magnetic body 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, rotating 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 magnet, stop rotating the propeller and read the distance data displayed by the propeller;

[0016] Step 5, rotating the screw propeller to move the soft magnet backward, so that the soft magnet and the magnet body are separated, until the magnet body returns to a stationary state;

[0017] Step 6, repeating steps 3 to 5 for multiple times and then stopping, obtaining distance data displayed by multiple propellers, and averaging 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] Further, 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] 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 of 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 to the soft magnet when it exceeds the critical distance. In the critical state, the force T on the nylon line is orthogonally decomposed in the horizontal and vertical directions:

[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 body, G is the gravity of the magnet body, α is the deflection angle of the magnet body under the critical state, and β is the horizontal angle between the magnet body and the soft magnetic body 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 magnetic body.

[0040] From formula (6), (7), (8), we get:

[0041]

[0042] 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. 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 proportionality coefficient, then:

[0045] m1=μH#(11)

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

[0047]

[0048] There is a constant difference between the distance x and d shown by the propeller. The constant can be positive or negative. Let the 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 measuring device and a measuring method thereof are provided in the present invention, wherein a soft magnetic body is placed in a magnetic field to be measured, so that an amplified magnetic field is generated around it, the soft magnetic body is moved close to the adsorbed magnetic body, so that the magnetic body is adsorbed onto the soft magnetic body, and a critical distance for adsorption is obtained. 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 the magnetic field direction of the magnetic field to be measured is obtained by using the mark on the magnetic body, thereby solving the problem of low measurement accuracy when traditional magnetic field measuring instruments measure 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] Figure 2 to Figure 4 They are the schematic diagrams of the weak magnetic field measurement device.

[0058] Figure 5 It is a fitting curve diagram of the magnetic field strength 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 strength 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 implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0062] like Figure 1 As shown, the present invention provides a weak magnetic field measuring device, which includes a lifting platform 1, on which a horizontal moving platform 2 and a suspension bracket 3 are arranged, the suspension bracket 3 is located on one side of the horizontal moving platform 2, and a fixed bracket 4 is arranged on the horizontal moving platform 2, and a soft magnet 5 is arranged at the end of the fixed bracket 4; a magnet 6 located on one side of the soft magnet 5 is suspended on the suspension bracket 3. The soft magnet 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 measuring device sets the soft magnetic body 5 in the magnetic field to be measured, so that it generates an amplified magnetic field around it, moves the soft magnetic body 5 close to the adsorbed magnet body 6, so that the magnet body 6 is adsorbed on the soft magnetic body 5, 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 the distance-magnetic field strength, and then the magnetic field direction of the magnetic field to be measured is obtained by using the mark on the magnet body 6.

[0063] The horizontal moving platform 2 includes a fixed platform 201 and a moving platform 202; the moving platform 202 is slidably connected to the fixed platform 201, and a screw propeller 7 is provided on one side of the moving platform 202, and the screw propeller 7 is used to drive the moving 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 moving platform 202, and the other end is provided with an installation groove, and a soft magnetic body 5 is fixed in the installation groove; the moving 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 needle fixedly connected to the bottom of the nylon line 8, and a magnet is respectively attached to both sides of the iron needle. 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 of a weak magnetic field measurement device, characterized by comprising:

[0066] Step 1, placing the soft magnetic body 5 and the magnetic 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, rotating the screw propeller 7, driving 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, rotating the screw propeller 7 to move the soft magnetic body 5 backward, so that the soft magnetic body 5 and the magnet body 6 are separated, until the magnet body 6 returns to a stationary state;

[0071] Step 6, repeating steps 3 to 5 for multiple times and then stopping, obtaining the distance data displayed by multiple propellers 7, and averaging the distance data of the 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 of obtaining the distance-magnetic field strength quadratic function expressions (1) and (2) includes:

[0080] like Figure 2 to Figure 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 magnet 5, and will be adsorbed onto the soft magnet 5 when the critical distance is exceeded. In the critical state, the force T exerted on the nylon line 8 is orthogonally decomposed in 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 under the critical state, and β is the angle between the magnet body 6 and the soft magnetic body 5 in the horizontal direction under 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 proportionality 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 formula (6), (7), (8), we get:

[0095]

[0096] During the experiment, the magnet 6 is made slightly lower than the soft magnetic body 5 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 proportionality coefficient, then:

[0099] m1=μH#(11)

[0100] From formula (3)(10)(11), we 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 distance-magnetic field strength quadratic function expressions (1) and (2) are fitted.

[0109] In summary, the weak magnetic field measuring device and the measuring method of the present invention are provided by placing the soft magnetic body 5 in the magnetic field to be measured so that it generates an amplified magnetic field around it, moving the soft magnetic body 5 close to the adsorbing magnet body 6 so that the magnet body 6 is adsorbed on the soft magnetic body 5, and obtaining 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 distance-magnetic field strength quadratic function expression, and the magnetic field direction of the magnetic field to be measured is obtained by using the mark on the magnet body 6, which solves the problem of low measurement accuracy when the traditional magnetic field measuring instrument measures weak magnetic fields.

Claims

1. A weak magnetic field measuring device, characterized in that: It comprises a lifting platform, on which a horizontal moving platform and a suspension bracket are arranged, the suspension bracket is located at one side of the horizontal moving platform, a fixed bracket is arranged on the horizontal moving platform, a soft magnet is arranged at the end of the fixed bracket; a magnet located at one side of the soft magnet is suspended on the suspension bracket.

2. The weak magnetic field measuring device according to claim 1, characterized in that: The horizontal moving platform comprises a fixed platform and a moving platform; the moving platform is slidably connected to the fixed platform, and a screw propeller is provided on one side of the moving platform, and the screw propeller is used to drive the moving 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 mobile platform, and the other end is provided with a mounting groove, in which the soft magnetic body is fixed; the mobile platform drives the fixed bracket and the soft magnetic body to move toward the magnet body.

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

4. A measurement method based on the weak magnetic field measurement device described in claim 3, characterized in that: include: Step 1, placing the soft magnetic body 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, rotating 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 magnet, stop rotating the propeller and read the distance data displayed by the propeller; Step 5, rotating the screw propeller to move the soft magnet backward, so that the soft magnet and the magnet body are separated, until the magnet body returns to a stationary state; Step 6, repeating steps 3 to 5 for multiple times and then stopping, obtaining distance data displayed by multiple propellers, and averaging 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.

5. The weak magnetic field measuring device according to claim 4, characterized in that: In step 7, the fitted distance-magnetic field strength quadratic function expression includes y=0.0104x 2 -0.2221x+1.3832 R 2 ＝0.9997 (1) y=0.011x 2 -0.2284x+1.3737 R 2 ＝0.9998 (2) 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.

6. The weak magnetic field measuring device according to claim 5, 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: H=nB (3) 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; The magnet body will swing under the attraction of the soft magnet, and will be adsorbed to the soft magnet when it exceeds the critical distance. In the critical state, the force T on the nylon line is orthogonally decomposed in the horizontal and vertical directions: F3cosβ=Tsinα (4) F H sinβ+Tcosα=G (5) Among them, F H is the magnetic force between the soft magnetic body and the magnet body, G is the gravity of the magnet body, α is the deflection angle of the magnet body under the critical state, and β is the horizontal angle between the magnet body and the soft magnetic body under the critical state; Substituting formula (4) into formula (5), we have: F H (sinβ+cosβcotα)=G#(6) 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: The mutual magnetic force F between the two H satisfy: 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 magnetic body. From formula (6), (7), (8), we 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. At this time, sinβ is approximately 0 and cosβ is approximately 1. The above formula (9) becomes: The magnetic pole strength generated by the magnetic charge is proportional to the magnetic field strength. Let μ be the proportionality coefficient, then: m1=μH#(11) From formula (3)(10)(11), we get: There is a constant difference between the distance x and d shown by the propeller. The constant can be positive or negative. Let the constant be a, then: make Then we have: B=C(x+a) 2 =C(x 2 +2ax+a 2 )#(15) 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. The distance-magnetic field strength quadratic function expressions (1) and (2) are fitted based on the fitting curve.

Images