Method and device for measuring the speed of a metal body

Abstract

The application relates to the technical field of measurement, in particular to a metal body movement speed measuring method and device, which is applied to a moving metal body to be measured and comprises a magnet device arranged above the metal body to be measured and used for generating a magnet magnetic field, a Hall sensor arranged between the metal body to be measured and the magnet device, and a single-chip microcomputer connected with the Hall sensor; when the metal body to be measured moves below the magnet device, the metal body to be measured generates an eddy current magnetic field; the Hall sensor senses a superimposed magnetic field of the magnet magnetic field and the eddy current magnetic field in the same preset direction; the single-chip microcomputer determines the movement speed of the metal body to be measured based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body to be measured, so that the movement speed of the metal body can be quickly and accurately obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of measurement technology, in particular to a kind of metal body movement speed measurement method and device. BACKGROUND

[0002] The measurement of the movement speed of metal material is of great significance in industry, for example, the movement speed of metal plate during processing needs to be monitored in manufacturing field, and the spindle speed of machine tool also needs to be measured; In the field of transportation, the relative movement speed between train and track needs to be measured when train is running, and the gear speed needs to be measured when car is running.

[0003] Therefore, how to accurately obtain the movement speed of metal material is a technical problem to be solved at present. SUMMARY

[0004] In view of the above problems, the present application is proposed to provide a kind of metal body movement speed measurement method and device to overcome the above problems or at least partially solve the above problems.

[0005] In the first aspect, the present application provides a kind of metal body movement speed measurement device, applied to the metal body to be measured in motion, comprising:

[0006] Magnet device is arranged above the metal body to be measured, for generating magnet magnetic field

[0007] Hall sensor is arranged between the metal body to be measured and the magnet device;

[0008] Single-chip microcomputer is connected with the Hall sensor;

[0009] When the metal body to be measured moves below the magnet device, the metal body to be measured generates eddy current magnetic field, the Hall sensor senses the superimposed magnetic field of the magnet magnetic field and the eddy current magnetic field in the same preset direction, and the single-chip microcomputer determines the movement speed of the metal body to be measured based on the superimposed magnetic field and the relationship between superimposed magnetic field and the movement speed of the metal body to be measured.

[0010] Preferably, the magnet device is a neodymium iron boron magnet or a coil.

[0011] Preferably, the distance between the metal body to be measured and the magnet device is 5mm-10mm.

[0012] Preferably, the Hall sensor is attached to the surface of the magnet device.

[0013] Preferably, the Hall sensor is arranged in different directions to sense the magnetic field in any of the following directions:

[0014] Horizontal direction, vertical direction or perpendicular direction;

[0015] The horizontal direction is parallel to the moving direction of the metal body to be measured, the vertical direction and the perpendicular direction are both perpendicular to the moving direction, and the vertical direction and the perpendicular direction are perpendicular to each other.

[0016] Preferably, the single-chip microcomputer comprises:

[0017] an analog-to-digital conversion module configured to convert the output voltage of the Hall sensor into a digital signal;

[0018] a processor configured to determine, based on the output voltage converted into the digital signal, that the Hall sensor senses a superimposed magnetic field of the magnetic field generated by the magnet device and the eddy current magnetic field generated by the metal body to be measured in the same preset direction, and determine, based on the superimposed magnetic field and a relationship between the superimposed magnetic field and the moving speed of the metal body to be measured, the moving speed of the metal body to be measured, wherein when the superimposed magnetic field is a superimposed magnetic field of the magnetic field and the eddy current magnetic field in the same horizontal direction, the relationship between the superimposed magnetic field and the moving speed of the metal body to be measured is as follows:

[0019]

[0020] wherein h is the height of the magnet device, M is the magnetization of the magnet device, μ is the magnetic permeability of the metal body to be measured, y0 is the distance between the magnet device and the metal body to be measured, and a is the radius of the magnet device,

[0021] a display screen configured to display the moving speed of the metal body to be measured.

[0022] Preferably, the metal body to be measured is in a moving motion or a rotating motion.

[0023] In a second aspect, the present application further provides a metal body moving speed measurement method, which is applied to the metal body moving speed measurement device in the first aspect and comprises the following steps:

[0024] When the metal body to be measured moves below the magnet device, the single-chip microcomputer acquires a superimposed magnetic field sensed by the Hall sensor, wherein the superimposed magnetic field is a superimposed magnetic field of a magnetic field generated by the magnet device and an eddy current magnetic field generated by the metal body to be measured in the same preset direction;

[0025] The single-chip microcomputer determines the moving speed of the metal body to be measured based on the superimposed magnetic field and a relationship between the superimposed magnetic field and the moving speed of the metal body to be measured.

[0026] Preferably, the single-chip microcomputer acquires the superimposed magnetic field sensed by the Hall sensor, and the method comprises the following steps:

[0027] The single-chip microcomputer acquires an output voltage of the Hall sensor.

[0028] Based on the output voltage, determine the superimposed magnetic field sensed by the Hall sensor.

[0029] Preferably, the single-chip microcomputer determines the movement speed of the metal body based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body, comprising:

[0030] The single-chip microcomputer determines the movement speed of the metal body based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body, and when the superimposed magnetic field is the superimposed magnetic field of the magnetic field and the eddy current magnetic field in the same horizontal direction, the relationship between the superimposed magnetic field and the movement speed of the metal body is as follows:

[0031]

[0032] Where h is the height of the magnet device, M is the magnetization intensity of the magnet device, μ is the magnetic permeability of the metal body, y0 is the distance between the magnet device and the metal body, and a is the radius of the magnet device.

[0033] The one or more technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

[0034] The present application provides a metal body movement speed measuring device applied to a moving metal body to be measured, comprising: a magnet device arranged above the metal body to be measured for generating a magnetic field, a Hall sensor arranged between the metal body to be measured and the magnet device, and a single-chip microcomputer connected to the Hall sensor. When the metal body to be measured moves below the magnet device, the metal body to be measured generates an eddy current magnetic field, the Hall sensor senses the superimposed magnetic field of the magnetic field and the eddy current magnetic field in the same preset direction, and the single-chip microcomputer determines the movement speed of the metal body to be measured based on the superimposed magnetic field of the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body to be measured, thereby quickly and accurately obtaining the movement speed of the metal body. BRIEF DESCRIPTION OF DRAWINGS

[0035] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of preferred embodiments, and are not meant to limit the present application. Moreover, the same reference numerals in different figures represent the same or similar components. In the drawings:

[0036] Figure 1 、 Figure 2 The structure of the metal body movement speed measuring device in the embodiment of the present application is shown in the structural schematic diagram;

[0037] Figure 3 A schematic diagram of the eddy current and the magnetic field of the eddy current in the embodiment of the present application is shown;

[0038] Figure 4 A diagram showing the relationship between the moving speed of the metal body to be measured and the superimposed magnetic field intensity sensed by the Hall sensor 103 in the embodiment of the present application is shown;

[0039] Figure 5 A schematic diagram showing the steps of the method for measuring the moving speed of the metal body in the embodiment of the present application is shown. DETAILED DESCRIPTION

[0040] Exemplary embodiments of the present disclosure will be described in detail with reference to the drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art.

[0041] Embodiment One

[0042] The embodiment of the present application provides a device for measuring the moving speed of a metal body, which is applied to a moving metal body to be measured 101, and the device comprises: Figure 1 、 Figure 2 a magnet device 102 arranged above the metal body to be measured 101 for generating a magnetic field of a magnet;

[0043] a Hall sensor 103 arranged between the metal body to be measured 101 and the magnet device 102;

[0044] a single-chip microcomputer 104 connected to the Hall sensor 103, when the metal body to be measured 101 moves below the magnet device 102, the metal body to be measured 101 generates an eddy current magnetic field, the Hall sensor 103 senses a superimposed magnetic field of the magnetic field of the magnet and the eddy current magnetic field in the same preset direction, and the single-chip microcomputer 104 determines the moving speed of the metal body to be measured 101 based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the moving speed of the metal body to be measured.

[0045] In the device for measuring the moving speed of the metal body, the magnet device is arranged such that the generated magnetic field is perpendicular to the moving direction of the metal body to be measured, and of course, other arrangements are also possible, which are not limited herein.

[0046] In an alternative embodiment, the single-chip microcomputer 104 comprises an analog-to-digital conversion module, a processor, and a display screen.

[0047] In an alternative embodiment, the single-chip microcomputer 104 comprises an analog-to-digital conversion module, a processor, and a display screen.

[0048] The analog-digital conversion module is configured to convert the output voltage of the Hall sensor into a digital signal; the processor is configured to determine, based on the output voltage converted into the digital signal, that the Hall sensor 103 senses a superimposed magnetic field of the magnetic field of the magnet and the eddy current magnetic field in the same preset direction, and determine, based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body 101, the movement speed of the metal body 101. When the superimposed magnetic field is a superimposed magnetic field of the magnetic field of the magnet and the eddy current magnetic field in the same horizontal direction, the relationship between the superimposed magnetic field and the movement speed of the metal body is as follows:

[0049]

[0050] wherein h is the height of the magnet device 102, M is the magnetization intensity of the magnet device 102, μ is the magnetic permeability of the metal body 101, y0 is the distance between the magnet device 102 and the metal body 101, and a is the radius of the magnet device 102, The display screen is configured to display the movement speed of the metal body 101.

[0051] In a specific embodiment, the Hall sensor 103 is configured to sense a superimposed magnetic field of the magnetic field of the magnet and the eddy current magnetic field in the same preset direction, and output a voltage value. When the superimposed magnetic field changes, the output voltage changes accordingly. Specifically, the change in the output voltage is proportional to the change in the magnetic induction intensity B of the superimposed magnetic field. The change in the magnetic induction intensity B of the superimposed magnetic field is related to the movement speed of the metal body 101.

[0052] The Hall sensor 103 is configured to sense a magnetic field in any of the following directions according to different setting directions:

[0053] horizontal direction, vertical direction, and perpendicular direction; wherein the horizontal direction is parallel to the movement direction of the metal body 101, the vertical direction and the perpendicular direction are both perpendicular to the movement direction, and the vertical direction and the perpendicular direction are perpendicular to each other.

[0054] Of course, according to the different setting directions of the Hall sensor 103, other directions of the superimposed magnetic field can also be sensed, which will not be described in detail herein. According to the sensing surface orientation of the Hall sensor 103, the direction of the sensed superimposed magnetic field is determined. Specifically, the sensing surface of the Hall sensor 103 is set to face different directions, so that the sensing surface of the Hall sensor 103 is perpendicular to the sensing surface of the superimposed magnetic field, thereby determining the direction of the superimposed magnetic field.

[0055] Suppose that the magnetic field of the magnet device 102 is B0, and when the metal body 101 moves at a speed v, the metal body 101 generates an eddy current 301, J EC= σv x B0, then according to the Biot-Savart law, the eddy current 301 further generates a magnetic field, i.e. the eddy current magnetic field 302, As Figure 2 , Figure 3 shown.

[0056] wherein μ0 is the vacuum permeability, r is the position vector of the eddy current to the Hall sensor, and V is the volume of the region where the eddy current is located.

[0057] Thus, the superimposed magnetic field vector B = B EC + B0of the magnet magnetic field and the eddy current magnetic field.

[0058] In order to obtain the specific quantitative relationship between the superimposed magnetic field vector and the velocity, the Maxwell equation is solved, and after combining each formula, the following is obtained:

[0059]

[0060] wherein M is the magnetization of the magnet device 102, μ is the permeability of the metal body 101 to be measured, σ is the conductivity of the metal body 101 to be measured, and B is the superimposed magnetic field vector. By solving, the superimposed magnetic field in the horizontal direction is:

[0061]

[0062] wherein h is the height of the magnet device 102, y0 is the distance between the magnet device 102 and the metal body 101 to be measured, and a is the radius of the magnet device 102.

[0063] Thus, the theoretical expression of the superimposed magnetic field in the horizontal direction with the movement velocity of the metal body 101 to be measured is obtained.

[0064] Of course, the theoretical expression of the superimposed magnetic field in the vertical direction or the perpendicular direction with the movement velocity of the metal body 101 to be measured can also be obtained, which is not described in detail here.

[0065] Thus, according to the above theoretical expression, combined with the value B x sensed by the Hall sensor 103, the movement velocity v of the metal body 101 to be measured can be determined, and finally the movement velocity of the metal body to be measured is displayed through the display screen.

[0066] As Figure 4 shown, it is the change relationship diagram between the movement velocity of the metal body to be measured and the superimposed magnetic field strength sensed by the Hall sensor 103, which includes the theoretical result and the actual result.

[0067] In an alternative embodiment, the magnet device 102 can be a permanent magnet, specifically a neodymium iron boron magnet.

[0068] In an alternative embodiment, the magnet device 102 can be a coil.

[0069] Both of the above-mentioned magnet devices 102 can generate a magnet magnetic field.

[0070] The distance between the metal body 101 to be measured and the magnet device 102 should be as close as possible, but the Hall sensor 103 needs to be arranged between the metal body 101 to be measured and the magnet device 102, so the distance between the metal body 101 to be measured and the magnet device 102 is preferably 5-10 mm.

[0071] In a preferred embodiment, the Hall sensor 103 can be attached to the surface of the magnet device 102. The sensitivity of the Hall sensor is selected to be 1.4 mV / Gs, and the range of the measured magnetic induction intensity is ±1400 Gs.

[0072] The movement of the metal body 101 to be measured in the embodiment of the application is specifically a moving movement or a rotating movement, which is not limited herein.

[0073] The one or more technical solutions in the embodiment of the application have at least the following technical effects or advantages:

[0074] The application provides a metal body movement speed measuring device applied to a metal body to be measured in movement, comprising: a magnet device arranged above the metal body to be measured, used for generating a magnet magnetic field; a Hall sensor arranged between the metal body to be measured and the magnet device; and a single-chip microcomputer connected to the Hall sensor. When the metal body to be measured moves below the magnet device, the metal body to be measured generates an eddy current magnetic field, the Hall sensor senses a superimposed magnetic field of the magnet magnetic field and the eddy current magnetic field in the same preset direction, and the single-chip microcomputer determines the movement speed of the metal body to be measured based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body to be measured, thereby quickly and accurately obtaining the movement speed of the metal body.

[0075] Embodiment two

[0076] Based on the same inventive concept, the application also provides a metal body movement speed measuring method applied to the metal body movement speed measuring device in embodiment one, as shown in Figure 5 , comprising:

[0077] S501, when the metal body to be measured moves below the magnet device, the single-chip microcomputer acquires the superimposed magnetic field sensed by the Hall sensor, the superimposed magnetic field being a superimposed magnetic field of the magnet magnetic field generated by the magnet magnetic field and the eddy current magnetic field generated by the metal body to be measured in the same direction;

[0078] S502, the single-chip microcomputer determines the movement speed of the metal body to be measured based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body to be measured.

[0079] In an optional implementation, S501 comprises: the single-chip microcomputer acquires the output voltage of the Hall sensor; and based on the output voltage, the superimposed magnetic field sensed by the Hall sensor is determined.

[0080] In an optional implementation, S502 comprises: the single-chip microcomputer determines the movement speed of the metal body to be measured based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body to be measured, wherein when the superimposed magnetic field is the superimposed magnetic field of the magnetic field and the eddy current magnetic field in the same horizontal direction, the relationship between the superimposed magnetic field and the movement speed of the metal body to be measured is as follows:

[0081]

[0082] wherein h is the height of the magnet device, M is the magnetization intensity of the magnet device, μ is the magnetic permeability of the metal body to be measured, y0 is the distance between the magnet device and the metal body to be measured, and a is the radius of the magnet device.

[0083] In a specific implementation, when the metal body to be measured moves below the magnet device, the electrons move under the action of the Lorentz force F=ev×B, so that the metal body to be measured forms a dynamic eddy current, the dynamic eddy current is annular and concentrates below the magnet device, according to the Biot-Savart law, the dynamic eddy current generates an eddy current magnetic field, so that the Hall sensor senses a superimposed magnetic field, that is, the superimposed magnetic field of the magnetic field generated by the magnet device and the eddy current magnetic field generated by the metal body to be measured in the same preset direction.

[0084] The Hall sensor converts the sensed superimposed magnetic field into an output voltage, the variation of the output voltage is proportional to the variation of the magnetic induction intensity B of the superimposed magnetic field, the single-chip microcomputer infers the variation of the magnetic induction intensity B of the superimposed magnetic field according to the variation of the output voltage, and the variation of the magnetic induction intensity of the superimposed magnetic field is related to the movement speed of the metal body to be measured, in the present application, the variation of the magnetic induction intensity of the superimposed magnetic field in the horizontal direction is related to the movement speed of the metal body to be measured as an example, so that the movement speed of the metal body to be measured can be obtained. Further, the movement speed of the metal body can be quickly and accurately acquired.

[0085] Example Three

[0086] Based on the same inventive concept, the embodiment of the present application provides a computer readable storage medium, which stores a computer program, the program is executed by a processor to implement the steps of the above-mentioned metal body movement speed measurement method.

[0087] The algorithms and displays presented herein are not inherently related to any particular computer, virtual system, or other apparatus. Various general purpose systems can be used with programs in accordance with the teachings herein, or it can prove convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these systems will be apparent from the description above. In addition, the present application is not intended to be limited to any particular programming language. It will be appreciated that there are many programming languages that can be used to implement the teachings herein, and any specific language can be chosen for use in this application.

[0088] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been described in detail in order to not obscure the understanding of this description.

[0089] Similarly, it is to be understood that the mechanical details of the application sometimes are presented in terms of certain spatially-related or geometrical configurations and / or descriptions. It will be appreciated by those skilled in the art that the application can be practiced in an almost endless variety of geometrical configurations, and that the specific configuration(s) described herein are merely intended to be representative of the many in which the application can be practiced. It is therefore to be understood that no language in the present specification should be construed as indicating any non-claimed element essential to the practice of the application.

[0090] Those skilled in the art will appreciate that the modules in the apparatuses in the embodiments can be adapted and placed in one or more apparatuses other than the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and further can be divided into more sub-modules or sub-units or sub-components. Any combination of all the features disclosed in the specification (including the accompanying claims, abstract and drawings), and any method or apparatus so disclosed, can be made unless specifically stated otherwise. Each feature disclosed in the specification (including the accompanying claims, abstract and drawings) can be replaced by alternative features serving the same, equivalent or similar purpose unless specifically stated otherwise.

[0091] Furthermore, those skilled in the art will recognize that, while certain embodiments described herein include certain features, not all embodiments need necessarily include those certain features. To the extent certain features, structures, or characteristics of an embodiment are described in connection with other embodiments, one skilled in the art would recognize such features, structures, or characteristics can be used in connection with other embodiments whether or not explicitly described.

[0092] Embodiments of various components of the present application can be implemented in hardware, software, or a combination thereof, and can be implemented with one or more computer programs or code that contain instructions to implement various functions described above. Embodiments of the present application can be implemented using software running on one or more processors that can be integrated with other components of the metal body movement speed measuring apparatus, computer device, or application-specific integrated circuit (ASIC). Embodiments also can be implemented using hardwired logic, logic circuitry, programmable logic device (PLD), field-programmable gate array (FPGA), server, computer, processor, or other components that can perform the various functions described throughout the specification.

[0093] It is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments of the present application will be apparent to those of skill in the art upon reviewing the above description. The scope of the application should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with their full scope of equivalents. In the claims, means- plus- function clauses are used where functionally equivalent structures are set forth with their supported operations. These structures are not limited to structures that are currently known to function in the manner described in the claims. In the context of the present disclosure, therefore, "means for" can be understood to mean "means for performing the function recited by the element that it is meant to replace, including structures not currently known that perform the recited function." The member of the present application is not limited by the numerical limitations recited in the claims, but can include a range of values that includes the recited values. The word "comprising" does not exclude the presence of elements or steps not recited in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a unitary or integrated claim, items such as multiple parts, clauses or steps are implemented either by one same item or by separate items performing the stated functions. The use herein of the term implying a specific order between elements or clauses, does not preclude such elements or clauses from being performed in a different order. The mere fact that different claims depend on a dependent claim, does not preclude those dependent claims from benefiting from the combination of features of the independent claim. The application covers both the following embodiments and the equivalents thereof.

Claims

1. A metal body movement speed measuring device characterized by comprising: The application is applied to a moving metal body to be measured, comprising: a magnet device arranged above the metal body to be measured for generating a magnetic field; a Hall sensor arranged between the metal body to be measured and the magnet device, the Hall sensor being arranged in different directions for sensing a magnetic field in any one of the following directions: a horizontal direction, a vertical direction and a perpendicular direction; wherein the horizontal direction is parallel to the moving direction of the metal body to be measured, the vertical direction and the perpendicular direction are both perpendicular to the moving direction, and the vertical direction is perpendicular to the perpendicular direction; a single-chip microcomputer connected to the Hall sensor; when the metal body to be measured moves below the magnet device, the metal body to be measured generates an eddy current magnetic field, the Hall sensor senses a superimposed magnetic field of the magnetic field and the eddy current magnetic field in the same preset direction, and the single-chip microcomputer determines the moving speed of the metal body to be measured based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the moving speed of the metal body to be measured; the single-chip microcomputer comprises: an analog-to-digital conversion module for performing analog-to-digital conversion on the output voltage of the Hall sensor; a processor for determining, based on the output voltage after analog-to-digital conversion, that the Hall sensor senses a superimposed magnetic field of the magnetic field and the eddy current magnetic field in the same preset direction, and determining, based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the moving speed of the metal body to be measured, the moving speed of the metal body to be measured; when the superimposed magnetic field is a superimposed magnetic field of the magnetic field and the eddy current magnetic field in the same horizontal direction, the relationship between the superimposed magnetic field and the moving speed of the metal body to be measured is as follows: ； wherein, is a height of the magnet device, is a magnetization of the magnet device, is a magnetic permeability of the metal body to be measured, is a distance between the magnet device and the metal body to be measured, is a radius of the magnet device, ; a display screen for displaying the moving speed of the metal body to be measured.

2. The metal body movement velocity measuring device according to claim 1, wherein The magnet device is a neodymium iron boron magnet or a coil.

3. The metal body movement velocity measuring device according to claim 1, wherein The distance between the metal body to be measured and the magnet device is 5mm-10mm.

4. The metal body movement velocity measuring device according to claim 1, wherein The Hall sensor is attached to the surface of the magnet device.

5. The metal body movement velocity measuring device according to claim 1, wherein The metal body to be measured is in a moving motion or a rotating motion.

6. A method of measuring the velocity of a metal body, which is applied to the metal body velocity measuring apparatus according to any one of claims 1 to 5, characterized by comprising: when the metal body to be measured moves below the magnet device, the single-chip microcomputer acquires a superimposed magnetic field sensed by the Hall sensor, the superimposed magnetic field being a superimposed magnetic field of a magnetic field generated by the magnet device and an eddy current magnetic field generated by the metal body to be measured in the same preset direction, the Hall sensor being arranged in different directions for sensing a magnetic field in any one of the following directions: a horizontal direction, a vertical direction and a perpendicular direction; wherein the horizontal direction is parallel to the moving direction of the metal body to be measured, the vertical direction and the perpendicular direction are both perpendicular to the moving direction, and the vertical direction is perpendicular to the perpendicular direction; the single-chip microcomputer determines the moving speed of the metal body to be measured based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the moving speed of the metal body to be measured, comprising: The single-chip microcomputer determines the movement speed of the metal body to be measured based on the superimposed magnetic field and the relationship between the superimposed magnetic field and the movement speed of the metal body to be measured, and when the superimposed magnetic field is the superimposed magnetic field of the magnet and the eddy current magnetic field in the same horizontal direction, the relationship between the superimposed magnetic field and the movement speed of the metal body to be measured is as follows: ； wherein, is the height of the magnet arrangement, is the magnetization of the magnet arrangement, is the magnetic permeability of the metal body to be measured, is the distance between the magnet arrangement and the metal body to be measured, is the radius of the magnet arrangement, .

7. The method of claim 6, wherein, The single-chip microcomputer acquires the superimposed magnetic field sensed by the Hall sensor, including: The single-chip microcomputer acquires the output voltage of the Hall sensor; Based on the output voltage, the superimposed magnetic field sensed by the Hall sensor is determined.

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