Electromagnetic induction detector, rod position measuring equipment and rod position measuring method

Abstract

The invention relates to the field of rod position measurement, in particular to an electromagnetic induction detector, rod position measurement equipment and a rod position measurement method. The electromagnetic induction detector comprises a soft magnetic induction block, a non-magnetic induction block, a control rod driving rod and N measuring coils. And at least one soft magnetic induction block and at least one non-magnetic induction block are arranged on the control rod driving rod in a crossed manner. Each measuring coil corresponds to a measuring voltage + and a measuring voltage-, and the N measuring coils at least comprise a first measuring coil and an Nth measuring coil. The N measuring coils are uniformly wound at intervals, the adjacent measuring coils are spaced by L mechanical steps, all the measuring coils are sequentially connected in series, and a constant small-current alternating-current excitation signal with a preset amplitude and a preset frequency is applied to the measuring coils. By designing the arrangement of the soft magnetic induction blocks and the non-magnetic induction blocks on the control rod drive rod, the technical problem that the actual position of the current control rod is difficult to accurately express by the existing rod position information is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of rod position measurement in nuclear power plants, and specifically relates to an electromagnetic induction detector, a rod position measurement device and a rod position measurement method. Background Art

[0002] The control rod position measurement system of a nuclear power plant is an important part of the reactor's primary circuit. Its main function is to measure the real-time position of the control rod in the reactor. The position information of the control rod can reflect the reactivity of the core to a certain extent. If it is detected that the current control rod has not reached the predetermined area, an alarm will be immediately issued to the operator in the main control room, and the operator will take corresponding corrective measures according to the regulations.

[0003] The rod position measurement of the coded detector based on the electromagnetic induction principle, which is currently commonly used both at home and abroad, is limited by the measurement principle and can only achieve a rod position measurement accuracy of 6 to 8 mechanical steps. That is, the obtained rod position information is difficult to accurately express the actual position of the current control rod. This rod position information is only provided as a reference for the operators in the main control room, and very few units use this rod position information as a reference for the calculation of reactor protection parameters. Summary of the invention

[0004] In view of this, the present application is committed to providing an electromagnetic induction detector, a rod position measurement device and a rod position measurement method based on a constant small current excitation type. By designing the spaced arrangement of soft magnetic induction blocks and non-magnetic induction blocks on the control rod drive rod, the induced electromotive force generated by the different positions of a group of coils and the soft magnetic induction blocks and the non-magnetic induction blocks is different, and the induced electromotive force of a group of coils at different positions of the control rod is collected and decoded, thereby accurately obtaining the current position of the control rod, solving the technical problem that the existing rod position information is difficult to accurately express the actual position of the current control rod.

[0005] In a first aspect, the present application provides an electromagnetic induction detector, which includes a soft magnetic induction block, a non-magnetic induction block, a control rod drive rod and N measuring coils. At least one soft magnetic induction block and at least one non-magnetic induction block are evenly arranged on the control rod drive rod. Each measuring coil corresponds to a measurement voltage + and a measurement voltage -, and the N measuring coils include at least a first measuring coil and an Nth measuring coil. The electromagnetic induction detector also includes an excitation power supply + corresponding to the first measuring coil and an excitation power supply - corresponding to the Nth measuring coil. The N measuring coils are evenly wound, and adjacent measuring coils are separated by L mechanical steps. All measuring coils are connected in series in sequence and are passed through a constant small current AC excitation signal with a preset amplitude and a preset frequency.

[0006] In a specific embodiment of the present application, the N measuring coils further include at least a second measuring coil and a third measuring coil.

[0007] In a specific implementation of the present application, the constant low-current AC excitation signal uses a low-current excitation of milliamperes.

[0008] The second aspect of the present application provides a rod position measurement device, which includes a processor, a rod position signal acquisition circuit and an excitation power supply output control circuit. The excitation power supply interface of the excitation power supply output control circuit is used to connect to the excitation power supply of the electromagnetic induction detector of the first aspect of the present application. The processor is connected to the rod position signal acquisition circuit and the excitation power supply output control circuit, and is used to control the excitation power supply output control circuit to supply power to the measuring coil of the electromagnetic induction detector to provide a constant small current AC excitation signal; obtain the voltage signals of the N measuring coils collected in real time by the rod position signal acquisition circuit, and calculate the rod position information (number of steps) with an accuracy of 1 mechanical step based on the voltage signal processing of the N measuring coils, and trigger an alarm when the voltage signal exceeds the limit; obtain the real-time voltage and current of the excitation power supply collected by the rod position signal acquisition circuit, and immediately cut off the excitation power supply output when an abnormality occurs, and trigger an alarm.

[0009] In a specific embodiment of the present application, the signal acquisition rate of the rod position signal acquisition circuit is higher than 10 times the excitation power frequency.

[0010] The third aspect of the present application provides a method for measuring the position of a control rod in a nuclear power plant, which is implemented using a processor of the rod position measuring device of the second aspect of the present application. The method for measuring the position of a control rod in a nuclear power plant comprises: using a fast Fourier change algorithm to calculate the amplitude of N measured voltages once in a fixed period to obtain N voltage amplitudes; eliminating values ​​with abnormal voltage amplitudes, sorting the remaining values, selecting the maximum and minimum values ​​from the remaining values, or selecting the second highest and second lowest values ​​from the remaining values, and obtaining the average of the two as the rod position threshold.

[0011] In a specific implementation of the present application, the nuclear power plant control rod position measurement method further includes: when the duration of the rod position change is greater than the dead time, controlling the rod position after the change is output. The dead time is not greater than the one-step action time.

[0012] In a specific embodiment of the present application, the method for measuring the position of control rods in a nuclear power plant further includes: performing bandpass filtering processing of the original signal at a target frequency, retaining the target characteristics of the signal, and filtering out the remaining noise signals.

[0013] In a specific embodiment of the present application, the nuclear power plant control rod position measurement method further includes: historically caching the calculated measurement coil amplitude, and performing low-pass filtering through a first-order Chebyshev filter to make the measurement coil amplitude curve smoother.

[0014] In a specific embodiment of the present application, the nuclear power plant control rod position measurement method also includes changing the rod position threshold from a single value to two values, a high threshold and a low threshold; when the measured voltage is higher than the high threshold or lower than the low threshold, controlling the rod position code change of the corresponding channel; when the measured voltage is lower than the high threshold and higher than the low threshold, keeping the original rod position code unchanged.

[0015] The beneficial effect of the technical solution of the present application is that: by winding N measuring coils at uniform intervals, adjacent measuring coils are spaced L mechanical steps apart, all measuring coils are connected in series in sequence, and a constant small current AC excitation signal with a preset amplitude and a preset frequency is passed through. According to Faraday's law of electromagnetic induction, the AC signal will generate a magnetic field near the measuring coil. Since the amplitude of the AC excitation signal is constant, the magnetic field can be considered constant without considering the influence of external magnetic fields. In addition, according to the characteristics of the soft magnetic induction block and the non-magnetic induction block, and by designing the interval arrangement of the soft magnetic induction block and the non-magnetic induction block on the control rod drive rod, the rod position code corresponding to each mechanical step is unique, thereby realizing the rod position measurement with an accuracy of one step. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shown is a schematic diagram of the composition of an electromagnetic induction detector provided in one embodiment of the present application.

[0017] Figure 2 Shown is the structure and topology diagram of a rod position measurement device provided in one embodiment of the present application.

[0018] Figure 3 Shown is an equivalent model diagram of a measuring coil provided in one embodiment of the present application.

[0019] Figure 4 Shown is a schematic diagram of the original waveform of the hot state measurement voltage provided in an embodiment of the present application.

[0020] Figure 5 Shown is a schematic diagram of the original waveform of the cold state measurement voltage provided in an embodiment of the present application.

[0021] Figure 6 Shown is a dynamic threshold effect diagram provided by an embodiment of the present application. DETAILED DESCRIPTION

[0022] As the requirements for economic efficiency and operational flexibility of the new generation of nuclear power technology continue to increase, the design of reactor protection functions must further tap the operating margin of nuclear power plant reactors and improve the operating flexibility of reactors. On the premise of ensuring the safety of the core, incorporating more accurate and reliable control rod position information into the fine calculation of reactor protection parameters can reduce the uncertainty of protection parameter calculation, increase the scope of safe operation of nuclear power plants, and effectively improve the economic efficiency of operation.

[0023] In order to obtain accurate and reliable control rod position information, at least one embodiment of the present application provides an electromagnetic induction detector, a rod position measurement device and a rod position measurement method.

[0024] 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.

[0025] At least one embodiment of the present application provides an electromagnetic induction detector (referred to as the detector for short), referring to Figure 1 The electromagnetic induction detector includes a soft magnetic induction block 1, a non-magnetic induction block 2, a control rod driving rod 3 and N measuring coils. The soft magnetic induction blocks 1 and the non-magnetic induction blocks 2 of different lengths are alternately and continuously arranged on the control rod driving rod 3. It should be noted that the length of the soft magnetic induction block or the non-magnetic induction block is an integer multiple of the mechanical step. Figure 1 Each small grid in the figure is a mechanical step, and the lengths of the soft magnetic induction blocks or non-magnetic induction blocks in different areas are not exactly the same. The soft magnetic induction blocks 1 and the non-magnetic induction blocks 2 are arranged alternately and continuously.

[0026] Each measuring coil corresponds to a measuring voltage + and a measuring voltage -, and the N measuring coils at least include a first measuring coil 4 and an Nth measuring coil 7. The electromagnetic induction detector also includes an excitation power supply + ( Figure 1 8) and the excitation power supply corresponding to the Nth measuring coil 7 - ( Figure 1 17). N measuring coils are wound evenly, and adjacent measuring coils are separated by L mechanical steps. All measuring coils are connected in series in sequence (the taps of two adjacent coils in each group of coils are positively connected), and a constant small current AC excitation signal with a preset amplitude and a preset frequency is passed through.

[0027] The soft magnetic induction block 1 is made of soft magnetic material and is easily magnetized. The non-magnetic induction block 2 is made of non-magnetic material and cannot be magnetized. Both the soft magnetic induction block and the non-magnetic induction block are integral multiples of the mechanical step.

[0028] The preset amplitude and the preset frequency can be selected according to the actual needs. On this basis, the preset amplitude and the preset frequency are not specifically limited in the embodiment of the present application. The measuring coil can also be called a rod position measuring coil. The electromagnetic induction detector is a constant small current excitation type electromagnetic induction detector, which can be referred to as a detector.

[0029] According to the technical solution provided in the embodiment of the present application, N measuring coils are wound evenly, and adjacent measuring coils are separated by L mechanical steps. All measuring coils are connected in series in sequence, and a constant small current AC excitation signal with a preset amplitude and a preset frequency is passed. According to Faraday's law of electromagnetic induction, the AC signal will generate a magnetic field near the measuring coil. Since the amplitude of the AC excitation signal is constant, the magnetic field can be considered constant without considering the influence of the external magnetic field. In addition, according to the characteristics of the soft magnetic induction block 1 and the non-magnetic induction block 2, and by designing the arrangement of the soft magnetic induction block 1 and the non-magnetic induction block 2 on the control rod drive rod, the rod position code corresponding to the mechanical step corresponding to each core height is unique, thereby realizing the rod position measurement with one-step accuracy. Using this rod position information with high accuracy and high confidence as the input for the calculation of core protection parameters can improve the calculation accuracy of protection parameters, reduce system calculation uncertainty, reduce the preset operating margin, further increase the safe operation range of the unit, and improve the economic efficiency of nuclear power plant operation. Accurate and reliable control rod position information can also provide a strong basis for reactor control in the main control room, greatly reducing the workload of the operators in the main control room.

[0030] It should be noted that Figure 1 The electromagnetic induction detector shown does not have a specific mechanical structure, but is only a schematic diagram.

[0031] In at least one embodiment of the present application, reference Figure 1 , the N measuring coils at least include a second measuring coil 5 and a third measuring coil 6. The measuring voltage + corresponding to the first measuring coil 4 is the measuring voltage 1+( Figure 1 9), the measured voltage corresponding to the first measuring coil 4 is the measured voltage 1-( Figure 1 10 in the figure). The measured voltage + corresponding to the second measuring coil 5 is the measured voltage 2+( Figure 1 11), the measured voltage corresponding to the second measuring coil 5 is the measured voltage 2-( Figure 1 12 in the figure). The measured voltage + corresponding to the third measuring coil 6 is the measured voltage 3+( Figure 1 13), the measured voltage corresponding to the third measuring coil 6 is the measured voltage 3-( Figure 1 14 in the figure). The measurement voltage + corresponding to the Nth measurement coil 7 is the measurement voltage N+ ( Figure 1 15), the measured voltage - corresponding to the Nth measuring coil 7 is the measured voltage N-( Figure 1 (16).

[0032] The measurement coils are arranged as follows:

[0033] First measuring coil: 1

[0034] Second measuring coil: 1+L

[0035] The third measuring coil: 1+2×L

[0036] …

[0037] Nth measuring coil: 1+(N-1)×L

[0038] In at least one embodiment of the present application, the constant low-current AC excitation signal uses a milliampere-level low-current excitation. In this way, the solution uses a milliampere-level low-current excitation to power the rod position detection, which has the advantages of low power consumption and high durability.

[0039] At least one embodiment of the present application also provides a rod position measurement device. Figure 2 The figure shows the topology of the rod position measurement device for a single bundle of rods.

[0040] refer to Figure 2 , the rod position measurement device includes a processor, a rod position signal acquisition circuit and an excitation power supply output control circuit. The excitation power supply interface of the excitation power supply output control circuit is used to connect to the excitation power supply of the electromagnetic induction detector of the above embodiment of the present application. The processor is connected to the rod position signal acquisition circuit and the excitation power supply output control circuit, and is used to control the excitation power supply output control circuit to supply power to the measuring coil of the electromagnetic induction detector to provide a constant small current AC excitation signal; obtain the voltage signals of the N measuring coils collected in real time by the rod position signal acquisition circuit, and calculate the rod position information (number of steps) with an accuracy of 1 mechanical step based on the voltage signal processing of the N measuring coils, and trigger an alarm when the voltage signal exceeds the limit; obtain the real-time voltage and current of the excitation power supply collected by the rod position signal acquisition circuit, and immediately cut off the excitation power supply output when an abnormality occurs, and trigger an alarm.

[0041] Specifically, if Figure 2 As shown, the rod position measuring device is connected to the electromagnetic induction detector of the above embodiment of the present application, and the rod position measuring device provides a constant low current AC excitation power supply to the electromagnetic induction detector, and the excitation power supply acts on N measuring coils. The voltage signal at both ends of each measuring coil is collected by the rod position signal acquisition circuit. The collected voltage signal is filtered and shaped to form a rod position code with N bits, and then the rod position code is converted into the number of steps that can represent the control rod position information by comparing the "code-step number correspondence table" through the table lookup method.

[0042] It should be noted that the rod position signal acquisition circuit can be an AD acquisition circuit.

[0043] In at least one embodiment of the present application, the signal acquisition rate of the rod position signal acquisition circuit is higher than 10 times the excitation power frequency, which is conducive to ensuring sufficiently high calculation accuracy.

[0044] Next, combine Figure 3The equivalent model of the measuring coil shown is used to illustrate the working principle of the electromagnetic induction detector.

[0045] Figure 3 The coil impedance Z = R + jωL of the measuring coil is measured, and the voltage across the coil is measured

[0046]

[0047] During the operation of the control rod, if the soft magnetic induction block 1 is close to the measuring coil of the detector, the soft magnetic induction block 1 is rapidly magnetized, and it also generates a magnetic field acting on the measuring coil. The measuring coil generates mutual inductance, which increases the inductance value L of the measuring coil. Under the constant small current excitation power supply, the voltage across the measuring coil increases; while when the non-magnetic induction block 2 is close to the measuring coil, it has basically no effect on the voltage across the measuring coil. There is a step-like change in the voltages of the two, and the middle section of the step can be used as the rod position threshold selection interval. When the measured voltage value is higher or lower than the threshold, the rod position of this channel is judged to be "0" or "1", thus forming a rod position code with N bits.

[0048] The equipment in nuclear power plants needs to consider both cold and hot working conditions, such as Figure 3 In the equivalent model of the rod position detector measuring coil shown in the figure, the resistance R increases with the increase of the coil ambient temperature, while the inductance L is basically not affected by the coil ambient temperature. This phenomenon is reflected in the coil measurement voltage, which is manifested as a higher measured voltage amplitude in the hot state, but the voltage amplitude difference between the N coils in the cold and hot states is about 1V, such as Figure 4 and Figure 5 shown.

[0049] Based on the above characteristics, at least one embodiment of the present application further provides a method for measuring the position of a control rod in a nuclear power plant, which is applicable to the rod position measurement of a small current excitation electromagnetic induction detector in a nuclear power plant. The execution subject of the method for measuring the position of a control rod in a nuclear power plant can be a processor of the rod position measurement device in the embodiment of the present application. The method for measuring the position of a control rod in a nuclear power plant includes the following steps.

[0050] S10: Calculate the amplitudes of N measured voltages once using a fast Fourier transform algorithm at a fixed period to obtain N voltage amplitudes.

[0051] S20: Eliminate the values ​​with abnormal voltage amplitudes, sort the remaining values, select the maximum value and the minimum value among the remaining values, or select the second highest value and the second lowest value among the remaining values, and calculate the average value of the two as the stick position threshold.

[0052] The effect achieved by using S10 and S20 can be as follows Figure 6 shown.

[0053] According to the technical solution provided in the embodiment of the present application, the characteristic that the voltage amplitude difference of N coils in the cold and hot states is about 1V is utilized, and a dynamic threshold is adopted to realize a rod position calculation method that takes into account both the cold and hot states, forming a dynamic threshold method that takes into account the rod position measurement under both cold and hot conditions, and the dynamic threshold does not require manual calibration. The embodiment of the present application realizes one-step accurate and highly reliable rod position measurement. At the same time, the rod position measurement method adopts a dynamic threshold method, which automatically adapts to cold and hot conditions. When the equipment arrives at the site, there is no need to debug and calibrate the rod position threshold, and the existing cumbersome and inefficient rod position debugging link is directly omitted, and more manpower and time are invested in the debugging of other key equipment. This situation has affected the economic benefits of nuclear power plants to a certain extent.

[0054] Abnormal rod position jumps are one of the pain points of rod position measurement in nuclear power plants. Abnormal rod position jumps are mainly caused by the noise of the measured voltage signal. The following measures can largely prevent the occurrence of abnormal rod position jumps and improve the reliability of the rod position measurement method.

[0055] In at least one embodiment of the present application, the method for measuring control rod positions in a nuclear power plant further includes S30.

[0056] S30: When the duration of the rod position change is greater than the dead time, the control output changes the rod position. The dead time is not greater than the one-step action time.

[0057] In the above embodiment, by adding a dead time mechanism for rod position changes, the dead time mechanism for adding a rod position change can avoid the occurrence of most abnormal rod position jumps, especially the rod position jumps caused by the uncertainty of the control rod movement during the moving rod movement process and the problem of asynchronous changes in N rod position codes.

[0058] In at least one embodiment of the present application, the method for measuring control rod positions in a nuclear power plant further includes S40.

[0059] S40: performing bandpass filtering of the target frequency on the original signal, retaining the target characteristics of the signal, and filtering out the remaining noise signals.

[0060] In at least one embodiment of the present application, the method for measuring control rod positions in a nuclear power plant further includes S50.

[0061] S50: caching the calculated measurement coil amplitude historically, and performing low-pass filtering through a first-order Chebyshev filter to make the measurement coil amplitude curve smoother.

[0062] In at least one embodiment of the present application, the method for measuring control rod positions in a nuclear power plant further includes S60 to S80.

[0063] S60: Changing the stick position threshold from a single value to two values, a high threshold and a low threshold.

[0064] S70: When the measured voltage is higher than the upper threshold or lower than the lower threshold, the rod position coding of the corresponding channel is controlled to change.

[0065] S80: When the measured voltage is lower than the high threshold and higher than the low threshold, the original rod position coding is kept unchanged.

[0066] In the above embodiment, a rod position threshold dead zone mechanism is added, and the threshold dead zone is the difference between the high threshold and the low threshold, and this value can be adjusted according to the specific conditions of the project.

[0067] It should be noted that the combination of the various technical features in the embodiments of the present application is not limited to the combination described in the embodiments of the present application or the combination described in the specific embodiments, and all technical features described in the present application can be freely combined or combined in any way unless there is a contradiction between them.

[0068] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "comprises" and "includes" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0069] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An electromagnetic induction detector, characterized in that: It includes a soft magnetic induction block, a non-magnetic induction block, a control rod driving rod and N measuring coils, among which: At least one soft magnetic induction block and at least one non-magnetic induction block are evenly arranged on the control rod driving rod, each measuring coil corresponds to a measuring voltage + and a measuring voltage -, the N measuring coils at least include a first measuring coil and an Nth measuring coil, the electromagnetic induction detector also includes an excitation power supply + corresponding to the first measuring coil and an excitation power supply - corresponding to the Nth measuring coil, the N measuring coils are evenly wound, adjacent measuring coils are spaced L mechanical steps apart, all the measuring coils are connected in series in sequence, and are passed through a constant small current AC excitation signal with a preset amplitude and a preset frequency.

2. The electromagnetic induction detector according to claim 1, characterized in that: The N measuring coils further include at least a second measuring coil and a third measuring coil.

3. The electromagnetic induction detector according to claim 1 or 2, characterized in that: The constant low-current AC excitation signal uses a low-current excitation of milliampere level.

4. A rod position measuring device, characterized in that: It includes a processor, a rod position signal acquisition circuit and an excitation power output control circuit. Wherein, the excitation power supply interface of the excitation power supply output control circuit is used to connect to the excitation power supply of the electromagnetic induction detector according to any one of claims 1 to 3; The processor is connected to the rod position signal acquisition circuit and the excitation power supply output control circuit, and is used to control the excitation power supply output control circuit to supply power to the measuring coil of the electromagnetic induction detector to provide a constant small current AC excitation signal; obtain the voltage signals of the N measuring coils collected in real time by the rod position signal acquisition circuit, and calculate the rod position information (number of steps) with an accuracy of 1 mechanical step based on the voltage signal processing of the N measuring coils, and alarm when the voltage signal exceeds the limit; obtain the real-time voltage and current of the excitation power supply collected by the rod position signal acquisition circuit, and immediately cut off the excitation power supply output in case of abnormality, and alarm.

5. The rod position measuring device according to claim 4, characterized in that: The signal acquisition rate of the rod position signal acquisition circuit is higher than 10 times the excitation power supply frequency.

6. A method for measuring the position of a control rod in a nuclear power plant, characterized in that: The method is implemented by using a processor of the rod position measurement device according to claim 4 or 5, wherein the method for measuring the rod position of a control rod in a nuclear power plant comprises: The amplitude of N measured voltages is calculated once using a fast Fourier transform algorithm at a fixed period to obtain N voltage amplitudes; Eliminate the values ​​with abnormal voltage amplitudes, sort the remaining values, select the maximum and minimum values ​​among the remaining values, or select the second highest and second lowest values ​​among the remaining values, and calculate the average of the two as the stick position threshold.

7. The method for measuring the position of a control rod in a nuclear power plant according to claim 6, characterized in that: Also includes: When the duration of the rod position change is greater than the dead time, the control output changes the rod position, wherein the dead time is not greater than the one-step action time.

8. The method for measuring the position of a control rod in a nuclear power plant according to claim 6, characterized in that: Also includes: The original signal is subjected to bandpass filtering at the target frequency to retain the target characteristics of the signal and filter out the remaining noise signals.

9. The method for measuring the position of a control rod in a nuclear power plant according to claim 6, characterized in that: Also includes: The calculated measurement coil amplitude is historically cached and low-pass filtered using a first-order Chebyshev filter to make the measurement coil amplitude curve smoother.

10. The method for measuring the position of a control rod in a nuclear power plant according to claim 6, characterized in that: Also includes: Change the stick position threshold from a single value to two values: high threshold and low threshold; When the measured voltage is higher than the high threshold or lower than the low threshold, the rod position coding of the corresponding channel is controlled to change; When the measured voltage is lower than the high threshold and higher than the low threshold, the original stick position encoding remains unchanged.

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