Device and method for measuring magnetic damping coefficient of conductor

Abstract

The invention discloses a conductor magnetic damping coefficient measuring device and method, and relates to the field of conductor characteristic measurement, in the conductor magnetic damping coefficient measuring device, a single-chip microcomputer auxiliary machine, a control center and a speed measuring device are connected with a single-chip microcomputer main machine; the driving module is respectively connected with the control center and the tension measuring device; the magnetic slide block is located on a horizontally placed target conductor track; the single-chip microcomputer auxiliary machine and the magnetic sliding block are connected with the tension measuring device. The control center controls the driving module to rotate at a constant speed to drive the tension measuring device to move at a constant speed, so that the magnetic sliding block slides on a target conductor track at a constant speed; the tension measuring device and the speed measuring device are used for measuring the tension measuring value and the speed of the magnetic sliding block when the magnetic sliding block slides at a constant speed; the single-chip microcomputer auxiliary machine corrects the tension measurement value; and the single-chip microcomputer host calculates the magnetic damping coefficient of the target conductor track according to the tension correction value, the speed and the friction force during constant-speed sliding. According to the invention, the measurement of the magnetic damping coefficient of the conductor can be simply and accurately realized.

Description

Technical Field

[0001] The present application relates to the field of conductor property measurement, and in particular to a device and method for measuring the magnetic damping coefficient of a conductor. Background Art

[0002] Magnetic damping is an important concept in electromagnetism. The mechanical effect it produces is widely used in practice. Magnetic damping is a phenomenon in which a conductor moving in a magnetic field is subject to resistance due to electromagnetic induction. The magnetic damping coefficient is used to measure the strength of this damping effect.

[0003] Measuring the magnetic damping coefficient is of great significance, as it helps to gain a deeper understanding of the relevant theories in electromagnetism and physics. By measuring and analyzing the magnetic damping coefficient, we can verify and improve the theoretical models in electromagnetism and promote the development of the discipline. Accurate measurement and research on the magnetic damping coefficient can promote the development of related technologies, provide a theoretical basis and data support for better utilization of electromagnetic phenomena, and at the same time, promote a more comprehensive understanding of electromagnetic phenomena in nature.

[0004] When studying the magnetic damping coefficient, it is usually involved in the movement experiment of the conductor in the magnetic field. The magnetic damping coefficient can be calculated by measuring the movement of the conductor under different conditions, such as speed, displacement, etc., and combining relevant electromagnetic theories and mathematical models. At present, the relevant magnetic damping coefficient measuring instruments usually place a magnetic slider on the inclined plane of the conductor, and measure the magnetic damping coefficient of the conductor by sliding the magnetic slider up and down. This method of measuring the magnetic damping coefficient by the inclination angle of the inclined plane has the following defects: it is necessary to determine the angle of the magnetic slider sliding down for uniform motion through experiments, and this experimental process is relatively cumbersome. After determining the angle of the slider for uniform motion, the time of the magnetic slider between the two sensors is measured. Since the trajectory of each slider movement is different, the measured time will be inconsistent, affecting the accuracy of the measurement results.

[0005] In summary, how to simply and accurately measure the magnetic damping coefficient of a conductor has become a problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present application is to provide a device and method for measuring the magnetic damping coefficient of a conductor, which can easily and accurately measure the magnetic damping coefficient of a conductor.

[0007] To achieve the above objectives, this application provides the following solutions:

[0008] In a first aspect, the present application provides a conductor magnetic damping coefficient measuring device, comprising: a single-chip computer host, a single-chip computer auxiliary machine, a control center, a drive module, a magnetic slider, a tension measuring device and a speed measuring device;

[0009] The single-chip microcomputer auxiliary machine, the control center and the speed measuring device are all connected to the single-chip microcomputer host; the tension measuring device is connected to the single-chip microcomputer auxiliary machine; the driving module is respectively connected to the control center and the tension measuring device; the magnetic slider is located on the horizontally placed target conductor track; the magnetic slider is connected to the tension measuring device;

[0010] The control center is used to receive the control instructions issued by the single-chip host, and control the driving module to rotate at a uniform speed according to the control instructions; the driving module is used to drive the tension measuring device to move at a uniform speed; the tension measuring device is used to drive the magnetic slider to slide at a uniform speed on the target conductor track, and measure the tension exerted on the magnetic slider when sliding at a uniform speed to obtain a tension measurement value; the single-chip auxiliary machine is used to correct the tension measurement value to obtain a tension correction value; the speed measuring device is used to measure the speed of the magnetic slider when sliding at a uniform speed; the single-chip host is used to calculate the magnetic damping coefficient of the target conductor track based on the tension correction value, the speed and the friction exerted on the magnetic slider when sliding at a uniform speed.

[0011] In a second aspect, the present application provides a method for measuring a magnetic damping coefficient of a conductor, wherein the method for measuring a magnetic damping coefficient of a conductor is implemented by using the above-mentioned device for measuring a magnetic damping coefficient of a conductor, and the method for measuring a magnetic damping coefficient of a conductor comprises:

[0012] Sending a control instruction and obtaining a tension correction value, a speed, and a friction force received by the magnetic slider when the magnetic slider slides at a uniform speed on a horizontally placed target conductor track; the tension correction value is obtained by correcting the tension received by the magnetic slider when the magnetic slider slides at a uniform speed;

[0013] The magnetic damping coefficient of the target conductor track is calculated according to the tension correction value, the speed, and the friction force to which the magnetic slider is subjected when sliding at a uniform speed.

[0014] According to the specific embodiments provided in this application, this application has the following technical effects:

[0015] The present application provides a device and method for measuring the magnetic damping coefficient of a conductor, wherein a magnetic slider is arranged on a horizontally placed target conductor track, and a driving module is controlled by a control center to rotate at a uniform speed, thereby driving a tension measuring device to move at a uniform speed, so that the magnetic slider slides at a uniform speed on the target conductor track, and the magnetic damping coefficient of the target conductor track is calculated by measuring the tension and speed of the magnetic slider when sliding at a uniform speed, combined with the friction force. Compared with the method of measuring the magnetic damping coefficient by using the inclination angle of an inclined plane, the present application does not need to determine the angle and time of the uniform motion, and can simply and accurately realize the measurement of the magnetic damping coefficient of the conductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a schematic diagram of the measurement principle of the magnetic damping coefficient of the conductor in this application;

[0018] Figure 2 A schematic diagram of the structure of a conductor magnetic damping coefficient measuring device provided in one embodiment of the present application;

[0019] Figure 3 A physical schematic diagram of a conductor magnetic damping coefficient measuring device provided in one embodiment of the present application;

[0020] Figure 4 A schematic diagram of a force measurement module circuit provided in an embodiment of the present application;

[0021] Figure 5 A circuit schematic diagram of a speed measurement module for measuring speed provided in an embodiment of the present application;

[0022] Figure 6 A schematic diagram of a display module circuit provided in an embodiment of the present application;

[0023] Figure 7 A schematic diagram of a control module circuit provided in an embodiment of the present application;

[0024] Figure 8 A diagram showing the relationship between the tension and the tension sensor reading provided in one embodiment of the present application;

[0025] Fig. 9 A diagram showing the relationship between tension and speed provided in one embodiment of the present application;

[0026] Fig.10 An embodiment of the present application provides Relationship diagram.

[0027] Figure numerals: power supply -1, control center -2, drive module -3, tension measuring device -4, flexible line -5, magnetic slider -6, target conductor track -7, single-chip host -8, fixed pulley -9, display module -10, speed measuring device -11, single-chip auxiliary -12. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0030] First, the design ideas and measurement principles of this application are introduced.

[0031] 1) Design ideas.

[0032] According to the problems existing in the existing measuring instruments (the measuring instruments that use the inclined plane inclination angle to measure the magnetic damping coefficient) when measuring the magnetic damping coefficient, the present application proposes to measure the magnetic damping coefficient based on the STM32 single chip microcomputer. The basic physical idea of ​​the present application is: the magnetic slider is placed on a horizontally placed conductor track, and the magnetic slider is connected to the tension measuring device and the driving module through a thin wire. The driving module is given a fixed frequency, and the driving module can rotate at a uniform speed, thereby driving the magnetic slider to move at a uniform speed. Since the magnetic slider is subjected to the magnetic resistance F when sliding at a uniform speed K , tension F 拉 and friction F 摩 At this time, the three forces are in equilibrium, and we can conclude that:

[0033] F 拉 =F K +F 摩 (1)

[0034] The magnetic resistance coefficient can be calculated by formula (1).

[0035] 2) Calibration of the tension measuring device.

[0036] The value displayed by the tension measuring device used in the designed measuring instrument is not the actual tension required. Therefore, the tension measuring device needs to be calibrated before use. Assuming that the applied external force is F, the value displayed by the tension measuring device is C 示 , and since the applied external force and the reading of the force sensor are in a linear relationship, we have:

[0037] C 示 =aF 拉 +c (2)

[0038] When calibrating, the external force can be changed. Different external forces correspond to different readings. Then the values ​​of a and c can be calculated using the linear fitting method. Thus, the following can be obtained:

[0039]

[0040] 3) Measurement principle.

[0041] When the magnetic slider moves on the conductor track, it will be hindered by electromagnetic induction. This hindering force is called magnetic damping force, and this force is proportional to the movement speed of the magnetic slider. Its proportional coefficient is the magnetic damping coefficient. From the above design concept, it can be seen that when the magnetic slider moves at a uniform speed under the pulling force provided by the drive module, the magnetic slider is subjected to a pulling force F 拉 , magnetic resistance F K and friction F 摩 The action of three forces, such as Figure 1 As shown. Since the slider is moving at a constant speed, the three forces are in equilibrium. Therefore, we have: F 拉 =F K +F 摩 .

[0042] Since the magnetic damping force is proportional to the speed, we have:

[0043] F K =Kv (4)

[0044] Since the friction force on the magnetic slider is a constant when it moves in a straight line at a uniform speed, let:

[0045] F 摩 =b (5)

[0046] Substituting equation (4) and equation (5) into equation (1), we get:

[0047] F 拉 =Kv+b (6)

[0048] From formula (6), we can know that as long as the pulling force at different speeds v is measured, the magnetic damping coefficient K and the dynamic friction force can be calculated by graphical method.

[0049] By transforming formula (6), we can get:

[0050]

[0051] In an exemplary embodiment, Figure 2 and Figure 3 As shown, a conductor magnetic damping coefficient measuring device is provided, including: a single-chip host 8, a single-chip auxiliary 12, a control center 2, a drive module 3, a magnetic slider 6, a tension measuring device 4 and a speed measuring device 11.

[0052] The single-chip microcomputer auxiliary machine 12, the control center 2 and the speed measuring device 11 are all connected to the single-chip microcomputer host 8; the tension measuring device 4 is connected to the single-chip microcomputer auxiliary machine 12; the driving module 3 is respectively connected to the control center 2 and the tension measuring device 4; the magnetic slider 6 is located on the horizontally placed target conductor track 7; the magnetic slider 6 is connected to the tension measuring device 4.

[0053] The control center 2 is used to receive the control instructions issued by the single-chip host 8, and control the driving module 3 to rotate at a uniform speed according to the control instructions; the driving module 3 is used to drive the tension measuring device 4 to move at a uniform speed; the tension measuring device 4 is used to drive the magnetic slider 6 to slide at a uniform speed on the target conductor track 7, and measure the tension exerted on the magnetic slider 6 when sliding at a uniform speed, and obtain the tension measurement value; the single-chip auxiliary machine 12 is used to correct the tension measurement value to obtain the tension correction value; the speed measuring device 11 is used to measure the speed of the magnetic slider 6 when sliding at a uniform speed; the single-chip host 8 is used to calculate the magnetic damping coefficient of the target conductor track 7 according to the tension correction value, the speed and the friction exerted on the magnetic slider 6 when sliding at a uniform speed.

[0054] In another exemplary embodiment of the present application, please refer to Figure 2 and Figure 3 The conductor magnetic damping coefficient measuring device also includes: a display module 10; the display module 10 is connected to the single-chip host 8; the display module 10 is used to display the tension measurement value, the tension correction value, the speed and the magnetic damping coefficient of the target conductor track 7.

[0055] In another exemplary embodiment of the present application, please refer to Figure 2 and Figure 3 The conductor magnetic damping coefficient measuring device further comprises: a fixed pulley 9 and a flexible wire 5. The fixed pulley 9 is arranged at the end of the target conductor track 7; one end of the flexible wire 5 is connected to the magnetic slider 6, and the other end of the flexible wire 5 bypasses the fixed pulley 9 and is connected to the tension measuring device 4.

[0056] In another exemplary embodiment of the present application, the calculation formula of the tension correction value is: Among them, F 拉 Indicates the tension correction value; C 示 represents the tension measurement value; a and c represent fitting parameters, which are determined by calibrating the tension measurement device 4.

[0057] In another exemplary embodiment of the present application, the calculation formula of the magnetic damping coefficient of the target conductor track 7 is: Where K represents the magnetic damping coefficient; F 拉 represents the tension correction value; v represents the speed; b represents the friction force.

[0058] In another exemplary embodiment of the present application, the tension measurement device 4 includes: a tension sensor.

[0059] Specifically, the experiment needs to measure the magnitude of the pulling force, which requires relatively high precision. Therefore, it is necessary to select a sensor with relatively high sensitivity. The model of the tension sensor selected in this embodiment is HZC-MS2-1kg, with a sensitivity of 2.0±0.1mv and a range of 0~1Kg, and is used in conjunction with the HX711 chip. The HX711 chip integrates peripheral circuits required by other chips of the same type, including a voltage-stabilized power supply and an on-chip clock oscillator. It has the advantages of high integration, fast response speed, and strong anti-interference. The tension sensor has two input channels, Channel A and Channel B. Channel A has a programmable gain of 128 or 64; Channel B has a fixed gain of 32. In this embodiment, Channel A is selected as the transmission channel of the tension sensor.

[0060] In this embodiment, the tension sensor needs to be debugged. The software used for simulation debugging of the tension sensor is linKboy. linKboy is an open source and free graphical programming simulation platform. It is simple to operate and easy to understand. You can use the mouse to interactively drag and drop to quickly build the programming logic to get a visual interface. When simulating, you only need to find the required components and drag them into the edit box. linKboy will prompt you to connect the lines. You only need to select a line from the lines it prompts.

[0061] During physical measurement, after the tension sensor is connected to the display module 10, a value can be observed on the display module 10, but it is obvious that the value on the display module 10 is not the magnitude of the force. Therefore, if the tension sensor needs to be used to measure the magnitude of the pulling force of pulling the slider, the accuracy of the tension sensor needs to be calibrated and debugged.

[0062] In another exemplary embodiment of the present application, the speed measurement device 11 includes: a Hall sensor.

[0063] In this embodiment, the Hall sensor is selected as the basic timing method. Since the magnetic slider 6 itself is magnetic and the Hall sensor is a relatively sensitive sensing module, it is most appropriate to select the Hall sensor for the speed measuring device 11. At the same time, after comparing multiple Hall sensors, this embodiment selects an A3144 Hall sensor with suitable size and price. Two Hall sensors can be used.

[0064] In this embodiment, the moving speed of the magnetic slider 6 needs to be obtained. The existing design idea is to measure the time and the moving distance of the magnetic slider 6 respectively and then calculate the speed, but the excessive amount of data obtained by this method may increase unnecessary errors. Therefore, this embodiment uses programming to directly calculate and display the speed. First, the Hall sensor is used to time, and then the program and the predetermined distance are used to calculate the speed, so as to convert the measured time into the required speed, which greatly reduces the workload of the experiment.

[0065] In another exemplary embodiment of the present application, the driving module 3 as a transmission device includes a stepping motor.

[0066] Specifically, in this embodiment, a fixed speed needs to be output, so the motor becomes the primary consideration, and among the various types of motors, the stepper motor is the most suitable. It can change its own speed according to different input frequencies, which is consistent with the need to change different pulling forces for multiple measurements. At the same time, after comparing different types of stepper motors, this embodiment selects the 57-input 2.8N motor of Pufeid.

[0067] The design ideas for stepper motor control in this embodiment are as follows:

[0068] The output frequency f of the stepper motor out It is determined by the update event frequency of the timer, that is, the number of times the DAC is triggered to update per second. Update event frequency f update The calculation formula is as follows:

[0069]

[0070] Where: f timer is the input clock frequency of the timer (usually the APB1 or APB2 clock frequency), "Prescaler" is the timer prescaler value, and "Period" is the timer auto-reload value (ARR).

[0071] The output frequency of the sine wave is f out and update frequency f update The relationship between them is:

[0072]

[0073] Use Keill to write the program, use Proteus simulation to check whether its functions are realized, and then burn it into stm32 through ST-LinK.

[0074] In another exemplary embodiment of the present application, the display module 10 includes a liquid crystal display screen.

[0075] Specifically, since a lot of information needs to be displayed on the display module 10, a relatively fine 1.8-inch RGB-TFT liquid crystal display screen can be selected. Compared with other display screens, this display screen can display more information at the same time for easy observation.

[0076] In another exemplary embodiment of the present application, since the single-chip microcomputer in this embodiment includes multiple functions such as numerical display of the tension measuring device 4, sinusoidal wave output of different frequencies, timing, etc., and they need to be combined together, two STM32 single-chip microcomputers are selected that can integrate multiple programs into one piece and can realize multiple functions such as function signal conversion and module timing. The model used by the single-chip microcomputer host 8 is STM32F407ZGT6, and the model used by the single-chip microcomputer slave 12 is STM32F103C8T6.

[0077] Figure 4-Figure 7 The circuit principle of the single-chip microcomputer control design part is shown, which includes a force measuring module (single-chip microcomputer auxiliary machine 12 and tension sensor) for measuring the tension of the magnetic slider 6, a speed measuring module for measuring the speed (the part of the single-chip microcomputer host 8 that realizes the speed measurement), a display module 10 for displaying the output frequency and the measured tension and the measured speed, and a control module for controlling the reset and adjustment of the frequency (the part of the single-chip microcomputer host 8 that realizes the switch control). These modules are controlled by the single-chip microcomputer through programming. Figure 4 In the figure, U4 represents the chip of the microcontroller 12, U5 represents the internal structure of the tension sensor, and PA2 and PA3 correspond to the solder joints on the actual object. Figure 5 U2 and U3 are interfaces of two Hall sensors on the single-chip host 8, and PA0 and PA1 correspond to solder joints on the actual object. Figure 6 PB6 and PB7 correspond to the solder joints on the actual object. Figure 7 PA5, PA6 and PA7 correspond to the solder joints on the actual object.

[0078] In another exemplary embodiment of the present application, please refer to Figure 3 The conductor magnetic damping coefficient measuring device also includes: a power supply 1; the power supply 1 is connected to the single-chip host 8.

[0079] The following is a detailed introduction to the experimental methods and experimental data of the conductor magnetic damping coefficient measurement device in actual application.

[0080] The experimental environment is: laboratory temperature: 20°C; experimental humidity: 74%; experimental pressure: 898hPa.

[0081] (I) Experimental procedures.

[0082] 1. Assemble the experimental instrument, connect the power supply 1 after leveling it with a level, turn on the power supply 1 and the MCU components (MCU host 8 and MCU slave 12) to preheat.

[0083] 2. Zero the tension sensor and hang a hook from the pulley at the rear.

[0084] 3. Place weights of equal mass (each weight is 20 g) on ​​the hooks in sequence, read the reading on the display module 10 and record it in the table.

[0085] 4. Use the local gravitational acceleration to calculate the force on the tension sensor and record it in the table. Make a fitting graph based on the obtained readings and force to find the values ​​of a and c.

[0086] 5. Adjust the voltage of power supply 1 to 20V, press the reset button to zero the tension sensor, and adjust the output frequency to 2000Hz.

[0087] 6. Close the switch to make the stepper motor start to rotate, observe the display module 10, read the tension, and after the tension sensor finishes recording the speed, open the switch to read the speed and record it in the experimental table.

[0088] 7. Measure and record the data multiple times, and process the data to obtain the average tension and average speed.

[0089] 8. Change the frequency to 4000Hz, 6000Hz, 8000Hz and 10000Hz, and repeat steps 4 and 5.

[0090] 9. Arrange the average tension and average speed of each frequency and make Fv graph based on the data, then perform linear fitting. According to the known formula F 拉 =Kv+b, the slope is the required magnetic damping coefficient K, and the intercept is the device friction force b.

[0091] 10. Carry out uncertainty calculation and error analysis, and conduct comparative analysis with existing measuring instruments.

[0092] (ii) Experimental data measurement and experimental data processing.

[0093] 1. Calibration of tension sensor.

[0094] The experimental data of tension sensor calibration can be obtained according to the experimental steps, as shown in Table 1.

[0095] Table 1 Sensor calibration measurement data

[0096] Weight mass / g External force / N Tension sensor reading 20 0.1958 1883 40 0.3916 3714 60 0.5874 5545 80 0.7832 7376 100 0.9790 9206

[0097] Use Excel's graphing function to draw a relationship diagram between the external force and the sensor reading, and fit a formula that represents the relationship between the external force on the tension sensor and the sensor reading. Figure 8 The slope is the change in the value of the tension sensor when a unit force acts on the tension sensor.

[0098] The function corresponding to the external force sensor reading is:

[0099] y=9350.6x+52.112 (10)

[0100] From the fitting results, we know the correlation coefficient R 2 =1, with a strong correlation, the slope of the fitted line is 9350.6, the intercept is 52.112, and from the slope of the line, it can be seen that when the force changes by 1N, the change value of the sensor is 9350.6. Therefore, after observing the reading, the output display data is substituted into the above formula (10), and the magnitude of the force applied to the force sensor can be calculated by this method.

[0101] 2. Measurement of magnetic damping coefficient.

[0102] Through the above experimental operations, the readings of the velocity and tension sensors measured at frequencies of 2000Hz, 4000Hz, 6000Hz, 8000Hz and 10000Hz were obtained (converted into N through calibration values), and the experimental data were recorded in Tables 2 to 6 respectively.

[0103] Table 2 Tension and speed measurement table at a frequency of 2000Hz

[0104] Number of experiments Indication Tension(N) Speed ​​(m / s) Number of experiments Indication Tension(N) Speed ​​(m / s) 1 884 0.089 0.120 7 884 0.098 0.120 2 903 0.091 0.120 8 903 0.090 0.120 3 903 0.091 0.120 9 903 0.092 0.120 4 894 0.090 0.120 10 894 0.091 0.120 5 884 0.089 0.120 11 884 0.089 0.120 6 894 0.090 0.120 12 894 0.090 0.120

[0105] Table 3 Tension and speed measurement table at a frequency of 4000Hz

[0106] Number of experiments Indication Tension(N) Speed ​​(m / s) Number of experiments Indication Tension(N) Speed ​​(m / s) 1 1548 0.160 0.240 7 1548 0.160 0.240 2 1558 0.161 0.240 8 1558 0.161 0.240 3 1539 0.159 0.241 9 1539 0.159 0.241 4 1539 0.159 0.241 10 1539 0.159 0.241 5 1558 0.161 0.240 11 1558 0.161 0.240 6 1548 0.160 0.241 12 1548 0.160 0.241

[0107] Table 4 Tension and speed measurement table at a frequency of 6000Hz

[0108] Number of experiments Indication Tension(N) Speed ​​(m / s) Number of experiments Indication Tension(N) Speed ​​(m / s) 1 2128 0.222 0.380 7 2137 0.223 0.379 2 2137 0.223 0.379 8 2128 0.222 0.380 3 2128 0.222 0.379 9 2128 0.222 0.379 4 2128 0.222 0.380 10 2137 0.223 0.380 5 2137 0.223 0.379 11 2137 0.223 0.379 6 2128 0.222 0.380 12 2128 0.222 0.380

[0109] Table 5 Tension and speed measurement table at frequency 8000Hz

[0110]

[0111]

[0112] Table 6 Tension and speed measurement table at frequency 10000Hz

[0113] Number of experiments Indication Tension(N) Speed ​​(m / s) Number of experiments Indication Tension(N) Speed ​​(m / s) 1 2680 0.281 0.490 7 2670 0.280 0.491 2 2670 0.280 0.491 8 2670 0.280 0.490 3 2680 0.281 0.490 9 2680 0.281 0.490 4 2670 0.280 0.491 10 2670 0.280 0.491 5 2680 0.281 0.491 11 2680 0.281 0.490 6 2680 0.281 0.490 12 2670 0.280 0.491

[0114] 3. Experimental data processing.

[0115] (1) Calculation of magnetic damping coefficient.

[0116] Calculate the average value of the tension and velocity measured at frequencies of 2000Hz, 4000Hz, 6000Hz, 8000Hz and 10000Hz, and fill in the calculation results in Table 7.

[0117] Table 7 Average tension and average speed at each frequency

[0118] Frequency (Hz) Average speed (m / s) Average pulling force(N) 2000 0.120 0.091 4000 0.240 0.160 6000 0.380 0.222 8000 0.411 0.240 10000 0.491 0.280

[0119] According to the average speed and average tension calculated in Table 7, it is found through observation that when the frequency increases, both the speed and tension increase. A scatter plot is made with speed as the horizontal axis and tension as the vertical axis, and then a linear fit is performed. The fitting results are shown in Fig. 9 shown.

[0120] Depend on Fig. 9 It can be seen that the relationship between speed and tension is:

[0121] y=0.5064x+0.0323 (11)

[0122] Its slope is 0.5064, its intercept is 0.0323, and its correlation coefficient is R 2 =0.9974, indicating that the tension and speed have a strong correlation. Compared with formula (6), the magnetic damping coefficient (unit: N·s / m) is:

[0123] K=0.5064 (12)

[0124] (2) Uncertainty calculation.

[0125] 1) Calculation of speed uncertainty.

[0126] Since the speed is read directly on the instrument, the Class B uncertainty is equal to the minimum scale value displayed by the instrument (unit: m / s), that is:

[0127] Δ B =0.001 (13)

[0128] Type A uncertainty:

[0129]

[0130] Therefore, the total velocity uncertainty is:

[0131]

[0132] 2) Calculation of uncertainty of tension.

[0133] Similarly, since the tension is also read directly on the instrument, the Class B uncertainty is equal to the minimum scale value displayed by the instrument (unit: N), that is:

[0134] Δ B =0.001 (16)

[0135] Type A uncertainty:

[0136]

[0137] Therefore, the uncertainty of the total tension is:

[0138]

[0139] 3) Uncertainty calculation of magnetic damping coefficient K.

[0140] Since the magnetic damping calculation formula is: That is, the magnetic damping coefficient K is calculated by the tension F and the speed v. Therefore, the uncertainty of the magnetic damping coefficient should be calculated by the uncertainty transfer formula, that is:

[0141]

[0142] Find the partial derivative of formula (19):

[0143]

[0144] Substituting in:

[0145]

[0146] The uncertainty of the magnetic damping coefficient measured at each frequency calculated by the above formula is shown in Table 8.

[0147] Table 8 Uncertainty calculation table of magnetic damping coefficient measured at each frequency

[0148] Frequency (Hz) Speed ​​(m / s) <![CDATA[Δ v (m / s)]]> <![CDATA[Δ F (N)]]> <![CDATA[Δ k (N·s / m)]]> Relative uncertainty 2000 0.120 0.001 0.003 0.011 2.17％ 4000 0.240 0.001 0.001 0.006 1.18％ 6000 0.380 0.003 0.001 0.005 0.99％ 8000 0.411 0.001 0.001 0.003 0.59％ 10000 0.491 0.001 0.001 0.003 0.59％

[0149] Average value of uncertainty of magnetic damping coefficient at different speeds (unit: N·m / s):

[0150]

[0151] Average relative uncertainty:

[0152]

[0153] 4. Experimental results.

[0154] The measured magnetic damping coefficient (unit: N·s / m) is: K=0.506±0.005;

[0155] 5. Experimental error analysis.

[0156] From the measurement results, we can see that the measurement uncertainty is 0.005 and the relative uncertainty is 0.99%. After analyzing the measuring instrument and the measurement process, the causes of the error are as follows:

[0157] (1) When the speed is different, the friction between the flexible wire 5 (such as a thin wire) and the fixed pulley 9 changes slightly, which affects the measurement error.

[0158] (2) When the slider slides on the slide rail, the magnetic slider 6 and the conductor track are worn. In this embodiment, if the magnetic slider 6 and the conductor track are used for a long time, the instrument will be relatively aged, which will have a certain impact on the experimental results.

[0159] (3) The approximate values ​​taken during experimental data processing will have a certain impact on the measurement results.

[0160] (4) There is an error in the standard value during calibration, which has a certain impact on the calibration result.

[0161] Therefore, the following points should be noted: (1) Before the experiment begins, check whether the Hall sensor mode is in the two-point timing mode to ensure that the timing can be completed. (2) During the experiment, the thin wire should be kept straight to prevent the trolley from being unstable during the pulling process. (3) Before the experiment, check the instrument yourself to prevent huge errors caused by improper operation of the experimental instrument.

[0162] The following is an experimental comparison and analysis of the measurement results of the existing measuring instrument (a measuring instrument for measuring the magnetic damping coefficient by the inclination angle of an inclined plane) and the measurement results of the conductor magnetic damping coefficient measuring device of the present application.

[0163] (a) Measure the magnetic damping coefficient using the original experimental instrument.

[0164] 1. Experimental data measurement.

[0165] First, the angle range of the slider's uniform linear motion is determined through experiments. Experiments are performed at different angles and measured 5 times at each angle. The measured experimental data are shown in Table 9.

[0166] Table 9 Experimental data for determining the angle range of the slider moving at a uniform speed

[0167]

[0168]

[0169] It can be clearly seen from Table 9 that when the value of ac is 0.4m to 0.65m, the angle range of the slider's uniform linear motion, that is, the slider's uniform linear motion when it slides down, is 49.46° to 66.42°. Select the experimental data when the values ​​of ac in Table 9 are 0.4m, 0.45m, 0.50m, 0.55m, 0.60m, and 0.65m and fill them in Table 10.

[0170] Table 10 Experimental data of the selected slider doing uniform linear motion

[0171]

[0172] 2. Experimental data processing.

[0173] (1) Measurement of magnetic damping coefficient.

[0174] According to the geometric relationship:

[0175] θ=arccosl ac (twenty four)

[0176] The measured data are processed and tanθ and The values ​​are recorded in Table 11.

[0177] Table 11 Experimental data calculation table

[0178] ac / m θ / ° t / s tanθ cosθ v / (m / s) v / cosθ / (m / s) 0.40 66.42 1.507 2.291 0.40 0.166 0.415 0.45 63.26 1.564 1.985 0.45 0.160 0.355 0.50 60.00 1.753 1.732 0.50 0.143 0.285 0.55 56.63 1.826 1.518 0.55 0.137 0.249 0.60 53.13 2.064 1.333 0.60 0.121 0.202 0.65 49.46 2.163 1.169 0.65 0.116 0.178

[0179] Use Excel to draw a graph and import tanθ and The value of tanθ is the ordinate, Plot as the horizontal axis and then perform a linear fit, such as Fig.10 shown.

[0180] Depend on Fig.10 The fitted function is:

[0181] y=4.594x+0.3823 (25)

[0182] The correlation coefficient is:

[0183] R 2 =0.9955 (26)

[0184] The correlation coefficient shows that tanθ and There is a strong linear correlation between them.

[0185] The mass of the slider was measured by an electronic scale to be 11.1×10 -3 kg, the local gravity acceleration g is 9.7897m / s 2 Substituting the specific value into K = a·mg, we get (unit: N·s / m):

[0186] K=0.499 (27)

[0187] (2) Uncertainty calculation.

[0188]

[0189] By transforming formula (28), we can get:

[0190]

[0191] The side-angle relationship (29) can be transformed into:

[0192]

[0193] Formula (30) for v 原 The derivatives are:

[0194]

[0195] The derivative of formula (31) with respect to l is:

[0196]

[0197] The magnetic damping coefficient K in the experiment 原 It is calculated by the angle θ between the inclined track and the horizontal plane and the speed v of the slider, so the uncertainty of the magnetic damping coefficient should be calculated by the indirect uncertainty formula. The calculation formula of the indirect uncertainty is as follows:

[0198]

[0199] For directly measured data, i.e. time t, distance l of ac, and distance L between two Hall sensors, the uncertainty of this type of data is calculated using the synthetic uncertainty, and the formula is as follows:

[0200]

[0201] The uncertainty of type A is U A for:

[0202]

[0203] Type B uncertainty U B for:

[0204] U B (x) = α 仪 (36)

[0205] First, use equations (34), (35) and (36) to calculate the time it takes for the slider to pass through the Hall sensor at different angles. Uncertainty Distance L from Hall sensor 原 The uncertainty U C (L 原 ) and ac, the uncertainty of the distance l C (l).

[0206] Uncertainty in calculation time First, substitute the measured time into equations (34), (35), and (36) to calculate the Type A uncertainty: and Type B uncertainty Combined uncertainty The values ​​are recorded in Table 12.

[0207] Table 12 Time uncertainty calculation table

[0208]

[0209] When calculating the uncertainty of the distance between ac and the distance between the Hall sensor, the distance between ac and the distance between the Hall sensor is a single measurement, and the type A uncertainty is not considered. The measuring tools used are all rulers with an accuracy of 0.001m. The combined uncertainty of the distance between ac and the distance between the Hall sensor is equal to the type B uncertainty. That is:

[0210] U C (l 原 )=U C (L 原 )=U B (l 原 )=U B (L 原 ) (37)

[0211] U B (l 原 )=U B (L 原 )=0.001 (38)

[0212] Use formula (39) to calculate the velocity corresponding to the angle.

[0213]

[0214] The partial derivative of formula (39) is:

[0215]

[0216] After calculating the uncertainty of time and the uncertainty of the distance between the Hall sensors, the velocity is calculated using equation (39). Equations (33), (38), (40) and (41) can be used to calculate the velocity and standard uncertainty U(v) corresponding to the inclination angle θ of the inclined track. 原i ), and record the calculation results in Table 13.

[0217] Table 13 Speed ​​uncertainty calculation table

[0218] <![CDATA[The distance l between a and c ac / m]]> Speed(m / s) Uncertainty (m / s) 0.40 0.166 0.002 0.45 0.160 0.001 0.50 0.143 0.002 0.55 0.137 0.002 0.60 0.121 0.001 0.65 0.116 0.002

[0219] Set the distance l of ac 原 The combined uncertainty and speed Substituting the standard uncertainty of into equation (34) we get The standard uncertainties are shown in Table 14.

[0220] Table 14 Uncertainty calculation table of magnetic damping coefficient

[0221]

[0222] It can be seen from Table 14 that the uncertainties of the magnetic damping coefficients are 0.009, 0.005, 0.004, 0.007, 0.008, and 0.006, respectively.

[0223] Average uncertainty (unit: N·s / m):

[0224]

[0225] The average relative uncertainty is:

[0226]

[0227] 3. Measurement results.

[0228] The measured magnetic damping coefficient (unit: N·s / m): k = 0.499 ± 0.007;

[0229] (ii) Comparative analysis of experimental instruments before and after improvement (existing measuring instruments and the conductor magnetic damping coefficient measuring device of the present application).

[0230] 1. The improved experimental equipment is more accurate.

[0231] From the above calculation, we can know that the relative uncertainty of the original experimental method is 1.4%, while the relative uncertainty measured by the improved experimental instrument of this application is 0.99%. By comparison, we can know that the data measured by the experimental scheme of this application is more accurate, that is, the improved experimental device improves the accuracy of the experiment compared with the original experimental device.

[0232] 2. The improved experimental instrument is easier to operate.

[0233] In the original experiment, it is necessary to first determine the angle of the slider sliding down to move at a uniform speed through experiments, and this experimental process is relatively cumbersome. After determining the angle of the slider moving at a uniform speed, the time of the slider between the two sensors is measured. Since the trajectory of each slider movement is different, the measured time will be inconsistent. When using the improved experimental instrument for measurement, many complex variables are reduced. When using the improved experimental instrument for measurement, it is only necessary to measure the tension and speed of the magnetic slider 6 to measure the magnetic damping coefficient through the drawing method. Compared with the original experimental instrument, the experimental operation is simpler and easier to operate.

[0234] 3. The experimental principles of the improved experimental instrument are easier to understand.

[0235] In the derivation of the experimental principle of the improved experimental instrument, only Newton's first law was used, while in the derivation of the experimental principle of the original experimental instrument, there were a large number of formulas and theoretical derivations. By comparison, it can be seen that the improved experimental instrument is not only simple to derive, but also the experiment is easier to understand and the physical ideas are richer. For subsequent learners, it is easier to understand the principles of the experiment, and it is easier for the instructor to explain the experiment.

[0236] From the above analysis, it can be seen that the present application converts the measurement of multiple physical quantities in the original experimental method into the measurement of tension and speed based on the principle of force balance, so as to facilitate the solution. The improved calculation formula is: F 拉 =KV+b. It can be seen from this formula that as long as the pulling force of the slider at different speeds is measured, the magnetic damping coefficient can be obtained by drawing, that is, the slope of the image obtained after fitting is the required magnetic damping coefficient K. The improved experimental method reduces the physical quantities that need to be measured in the experiment and is also more convenient to operate. By comparing the measurement results, the standard uncertainty of the measurement results of the improved experimental instrument is 0.005, the relative uncertainty is 0.99%, and the standard uncertainty of the measurement results of the original experimental instrument is 0.007, the relative uncertainty is 1.4%, and the measurement accuracy is also improved.

[0237] Subsequent researchers can further expand and improve this application in the following aspects:

[0238] (1) In the improvement of this experimental instrument, the measurement of tension and speed is displayed on the display module 10, and the experimental data cannot be directly collected by computer. In subsequent improvements, software can be used to connect the microcontroller components together to directly collect data through the computer, which can further save manpower and resources.

[0239] (2) When using the experimental instrument of the present application to conduct experiments, after each experiment, the stepper motor needs to be reversed to return the slider to the initial position, and the frequency needs to be set again to change the rotation direction of the stepper motor to conduct the experiment. The process is relatively cumbersome. In subsequent experimental improvements, a device that can pull the slider back to the starting position can be installed.

[0240] The embodiment of the present application measures the magnetic damping coefficient based on the controlled movement of the magnetic slider 6, which can easily and accurately achieve the measurement of the magnetic damping coefficient of the conductor.

[0241] Based on the same inventive concept, the embodiment of the present application also provides a conductor magnetic damping coefficient measuring method implemented by the conductor magnetic damping coefficient measuring device involved above. The implementation scheme for solving the problem provided by the method is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more conductor magnetic damping coefficient measuring method embodiments provided below can refer to the limitations of the conductor magnetic damping coefficient measuring device above, and will not be repeated here.

[0242] In an exemplary embodiment, a method for measuring a magnetic damping coefficient of a conductor is provided. The method for measuring a magnetic damping coefficient of a conductor is implemented by using the above-mentioned device for measuring a magnetic damping coefficient of a conductor. The method for measuring a magnetic damping coefficient of a conductor includes:

[0243] (1) issuing a control instruction and obtaining a tension correction value, a speed, and a friction force of the magnetic slider 6 when the magnetic slider 6 slides at a uniform speed on a horizontally placed target conductor track 7; the tension correction value is obtained by correcting the tension of the magnetic slider 6 when the magnetic slider 6 slides at a uniform speed.

[0244] (2) Calculating the magnetic damping coefficient of the target conductor track 7 based on the tension correction value, the speed, and the friction force to which the magnetic slider 6 is subjected when sliding at a uniform speed.

[0245] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0246] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A conductor magnetic damping coefficient measuring device, characterized in that: The conductor magnetic damping coefficient measuring device comprises: a single-chip computer host, a single-chip computer auxiliary machine, a control center, a driving module, a magnetic slider, a tension measuring device and a speed measuring device; The single-chip microcomputer auxiliary machine, the control center and the speed measuring device are all connected to the single-chip microcomputer host; the tension measuring device is connected to the single-chip microcomputer auxiliary machine; the driving module is respectively connected to the control center and the tension measuring device; the magnetic slider is located on the horizontally placed target conductor track; the magnetic slider is connected to the tension measuring device; The control center is used to receive the control instructions issued by the single-chip host, and control the driving module to rotate at a uniform speed according to the control instructions; the driving module is used to drive the tension measuring device to move at a uniform speed; the tension measuring device is used to drive the magnetic slider to slide at a uniform speed on the target conductor track, and measure the tension exerted on the magnetic slider when sliding at a uniform speed to obtain a tension measurement value; the single-chip auxiliary machine is used to correct the tension measurement value to obtain a tension correction value; the speed measuring device is used to measure the speed of the magnetic slider when sliding at a uniform speed; the single-chip host is used to calculate the magnetic damping coefficient of the target conductor track based on the tension correction value, the speed and the friction exerted on the magnetic slider when sliding at a uniform speed.

2. The conductor magnetic damping coefficient measuring device according to claim 1, characterized in that: The conductor magnetic damping coefficient measuring device also includes: a display module; the display module is connected to the single-chip host; the display module is used to display the tension measurement value, the tension correction value, the speed and the magnetic damping coefficient of the target conductor track.

3. The conductor magnetic damping coefficient measuring device according to claim 1, characterized in that: The conductor magnetic damping coefficient measuring device also includes: a fixed pulley and a flexible wire; The fixed pulley is arranged at the end of the target conductor track; one end of the flexible wire is connected to the magnetic slider, and the other end of the flexible wire bypasses the fixed pulley and is connected to the tension measuring device.

4. The conductor magnetic damping coefficient measuring device according to claim 1, characterized in that: The calculation formula of the magnetic damping coefficient of the target conductor track is: Where K represents the magnetic damping coefficient; F 拉 represents the tension correction value; v represents the speed; b represents the friction force.

5. The conductor magnetic damping coefficient measuring device according to claim 1, characterized in that: The model of the single-chip host is STM32F407ZGT6; the model of the single-chip slave is STM32F103C8T6.

6. The conductor magnetic damping coefficient measuring device according to claim 1, characterized in that: The tension measuring device comprises: a tension sensor.

7. The conductor magnetic damping coefficient measuring device according to claim 1, characterized in that: The speed measuring device comprises: a Hall sensor.

8. The conductor magnetic damping coefficient measuring device according to claim 1, characterized in that: The driving module includes a stepping motor.

9. The conductor magnetic damping coefficient measuring device according to claim 2, characterized in that: The display module includes a liquid crystal display screen.

10. A method for measuring the magnetic damping coefficient of a conductor, characterized in that: The conductor magnetic damping coefficient measuring method is implemented by using the conductor magnetic damping coefficient measuring device according to any one of claims 1 to 9, and the conductor magnetic damping coefficient measuring method comprises: Sending a control instruction and obtaining a tension correction value, a speed, and a friction force received by the magnetic slider when the magnetic slider slides at a uniform speed on a horizontally placed target conductor track; the tension correction value is obtained by correcting the tension received by the magnetic slider when the magnetic slider slides at a uniform speed; The magnetic damping coefficient of the target conductor track is calculated according to the tension correction value, the speed, and the friction force to which the magnetic slider is subjected when sliding at a uniform speed.

Images