Eddy current displacement sensor and temperature drift compensation method

Abstract

The embodiment of the invention provides an eddy current displacement sensor and a temperature drift compensation method. The eddy current displacement sensor comprises a probe, a cable and a front-end device, the probe comprises a metal probe protection cover, and a measuring coil, a metal partition plate, a compensating coil, a metal pressing sheet and a framework body which are arranged in the metal probe protection cover, and the measuring coil, the metal partition plate, the compensating coil and the metal pressing sheet are sequentially arranged on the framework body; the first end of the compensating coil and the first end of the measuring coil are both connected with the front-end device, and the front-end device is used for carrying out differential processing on a measuring signal sensed by the measuring coil and a compensating signal sensed by the compensating coil to obtain distance information. The sensor provided by the embodiment of the invention can provide high-precision displacement measurement in a complex environment, is suitable for various industrial application scenes, especially in an environment with high temperature or large temperature fluctuation, and ensures the reliability and accuracy of a measurement result.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of displacement sensors, and in particular to an eddy current displacement sensor and a temperature drift compensation method. Background Art

[0002] Eddy current displacement sensor is a non-contact measuring device based on the principle of electromagnetic induction, used to measure parameters such as displacement, vibration, and deformation of metal conductors.

[0003] In related art, an eddy current displacement sensor includes a sensor coil. The distance between the test object and the eddy current displacement sensor is measured by detecting the impedance change of the sensor coil when the test object approaches the sensor coil.

[0004] However, in the process of realizing this application, the inventors found that there are at least the following problems in the prior art: the performance of the above-mentioned eddy current displacement sensor is significantly reduced in harsh environments such as high temperature, high humidity, and radiation, and the measurement accuracy is low. Summary of the Invention

[0005] The embodiments of the present application provide an eddy current displacement sensor and a temperature drift compensation method to improve the measurement accuracy of the eddy current displacement sensor.

[0006] In a first aspect, an embodiment of the present application provides an eddy current displacement sensor, comprising:

[0007] Probes, cables and preamplifiers;

[0008] The probe includes a metal probe protective cover, and a measuring coil, a metal partition, a compensation coil, a metal pressing sheet and a frame body arranged in the metal probe protective cover; the measuring coil, the metal partition, the compensation coil and the metal pressing sheet are arranged on the frame body in sequence;

[0009] The first end of the compensation coil and the first end of the measuring coil are both connected to the proximitor; the second end of the compensation coil and the second end of the measuring coil are both connected to a first common end;

[0010] The metal partition is used to isolate the measuring coil and the compensation coil;

[0011] The metal pressing sheet is used to fix the position of the compensation coil and is symmetrical with the front end of the metal probe protective cover relative to the metal partition, so that the compensation coil and the measuring coil change in the same way as the temperature changes;

[0012] The measuring coil is used to generate eddy currents on the surface of the test object, generate different impedances under the influence of different eddy currents, and is also used to serve as the first arm of the bridge circuit to output a measurement signal; the magnitude of the eddy current is related to the distance between the measuring coil and the test object;

[0013] The compensation coil is used to change synchronously with the measuring coil in response to temperature changes, and is also used to serve as the second arm of the bridge circuit to output a compensation signal;

[0014] The preamplifier is used to perform differential processing on the measurement signal and the compensation signal to obtain distance information.

[0015] In one possible design, the probe further includes: a first insulating layer disposed between the measuring coil and the metal partition, and a second insulating layer disposed between the metal partition and the compensation coil; the first insulating layer is part of the frame body, and / or the second insulating layer is part of the frame body;

[0016] The first insulating layer is used to maintain insulation between the measuring coil and the metal partition;

[0017] The second insulating layer is used to maintain insulation between the compensation coil and the metal separator.

[0018] In one possible design, the preamplifier includes: a third bridge arm and a fourth bridge arm of a bridge circuit, a compensation channel, a measurement channel, an amplifier, and a microprocessor;

[0019] The first end of the third bridge arm and the first end of the second bridge arm are connected to the input end of the compensation channel, and the first end of the fourth bridge arm and the first end of the first bridge arm are connected to the input end of the measurement channel;

[0020] The output end of the compensation channel is connected to the first input end of the amplifier, and the output end of the measurement channel is connected to the second input end of the amplifier; the output end of the amplifier is connected to the microprocessor;

[0021] The compensation channel is used to process the compensation signal to obtain a compensation output signal;

[0022] The measurement channel is used to process the measurement signal to obtain a measurement output signal;

[0023] The amplifier is configured to perform differential processing on the compensation output signal and the measurement output signal to obtain a differential signal;

[0024] The microprocessor is used to determine distance information according to the differential signal.

[0025] In one possible design, the cable is a two-core shielded cable; the third bridge arm includes: a first resistor and a first capacitor; the fourth bridge arm includes: a second resistor and a second capacitor; the preamplifier further includes an excitation signal generator;

[0026] The shield end of the cable is connected to the first common end and is grounded; the first end of the first capacitor is connected to the compensation coil through the first core wire of the cable, the first end of the second capacitor is connected to the measuring coil through the second core wire of the cable, the second end of the first capacitor is connected to the second common end through the first resistor, the second end of the second capacitor is connected to the second common end through the second resistor, and the second common end is connected to the excitation signal generator;

[0027] The excitation signal generator is used to provide an excitation signal for the bridge circuit.

[0028] In one possible design, the compensation channel and the measurement channel are symmetrically arranged; the compensation channel includes: a first high-pass filter, a first buffer, and a first low-pass filter connected in sequence; the measurement channel includes: a second high-pass filter, a second buffer, and a second low-pass filter connected in sequence;

[0029] The first high-pass filter is used to filter the noise signal in the output signal corresponding to the compensation coil to obtain a first high-pass signal;

[0030] The first buffer is configured to drive the first high-pass signal to obtain a first driving signal;

[0031] The first low-pass filter is configured to perform AC-DC conversion on the first driving signal to obtain the compensated output signal;

[0032] The second high-pass filter is used to filter the noise signal in the output signal corresponding to the measuring coil to obtain a second high-pass signal;

[0033] The second buffer is configured to drive the second high-pass signal to obtain a second driving signal;

[0034] The second low-pass filter is used to perform AC-DC conversion on the second driving signal to obtain the measurement output signal.

[0035] In one possible design, the amplifier includes: an instrumentation amplifier and a proportional amplifier;

[0036] The first input terminal of the instrumentation amplifier is connected to the output terminal of the compensation channel, and the second input terminal of the instrumentation amplifier is connected to the output terminal of the measurement channel; the input terminal of the proportional amplifier is connected to the output terminal of the instrumentation amplifier, and the output terminal of the proportional amplifier is connected to the microprocessor;

[0037] The instrumentation amplifier is configured to differentially amplify the compensation output signal and the measurement output signal to obtain an initial differential signal;

[0038] The proportional amplifier is used to proportionally amplify the initial differential signal to obtain a target differential signal;

[0039] The microprocessor is used to process the target differential signal to obtain the distance information.

[0040] In one possible design, the preamplifier further includes: a half-wave rectifier;

[0041] The input end of the half-wave rectifier is connected to the output end of the compensation coil, and the output end of the half-wave rectifier is connected to the output end of the instrumentation amplifier and the input end of the proportional amplifier;

[0042] The half-wave rectifier is used to extract the DC component of the output signal corresponding to the compensation coil, and compensate the initial differential signal according to the DC component.

[0043] In one possible design, the preamplifier further includes: a voltage-to-current converter;

[0044] The voltage-to-current converter is connected to the microprocessor and is used to convert the voltage signal corresponding to the distance information to obtain the current signal corresponding to the distance information.

[0045] In one possible design, the eddy current displacement sensor is suitable for a working environment that meets at least one of the following conditions: temperature less than or equal to 260° C., humidity less than or equal to 100%, and radiation dose less than or equal to 100 kGy.

[0046] In a second aspect, an embodiment of the present application provides a temperature drift compensation method, comprising:

[0047] Obtaining a differential signal between a compensation output signal output by the compensation channel and an amplifier output;

[0048] Determining a current temperature based on the compensated output signal and a preset correspondence relationship, and determining a correction value corresponding to the compensated output signal based on the current temperature; the preset correspondence relationship includes a one-to-one correspondence between voltage values of multiple compensated output signals and multiple temperatures, and a one-to-one correspondence between multiple temperatures and multiple correction values;

[0049] determining an initial distance according to the differential signal;

[0050] The initial distance is corrected according to the correction value to obtain the distance information.

[0051] In a third aspect, an embodiment of the present application provides an eddy current displacement sensor device, comprising: at least one processor and a memory;

[0052] The memory stores computer-executable instructions;

[0053] The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor performs the method described in the first aspect and various possible designs of the first aspect.

[0054] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the method described in the first aspect and various possible designs of the first aspect is implemented.

[0055] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the method described in the first aspect and various possible designs of the first aspect.

[0056] The eddy current displacement sensor and temperature drift compensation method provided in this embodiment include a probe, a cable, and a preamplifier. The probe includes a metal probe protective cover, a measuring coil, a metal partition, a compensation coil, a metal pressing plate, and a frame body arranged within the metal probe protective cover. The measuring coil, metal partition, compensation coil, and metal pressing plate are sequentially arranged on the frame body. The first end of the compensation coil and the first end of the measuring coil are both connected to the preamplifier, and the second end of the compensation coil and the second end of the measuring coil are both connected to a first common terminal. The preamplifier is used to perform differential processing on the measurement signal sensed by the measuring coil and the compensation signal sensed by the compensation coil to obtain distance information. The sensor provided in this embodiment effectively isolates the measuring coil and the compensation coil by introducing a metal partition into the probe, preventing the eddy current generated by the test piece from affecting the compensation coil, thereby improving measurement accuracy. The metal pressing plate fixes the position of the compensation coil and forms a symmetrical structure with the metal probe protective cover, so that the compensation coil and the measuring coil have the same response to temperature changes. This design ensures that the compensation coil and the measuring coil change synchronously when the temperature changes, thereby achieving effective temperature drift compensation and further improving the accuracy and stability of the measurement. Furthermore, the measuring coil and compensation coil, acting as arms of the bridge circuit, respectively, output measurement and compensation signals. The preamplifier performs differential processing on these two signals, eliminating errors caused by environmental factors and temperature fluctuations and directly obtaining distance information. This differential processing method improves the system's anti-interference capability and signal processing accuracy. Overall, the sensor's well-designed structure enables high-precision displacement measurement in complex environments, making it suitable for a variety of industrial applications, particularly in environments with high temperatures or large temperature fluctuations, ensuring the reliability and accuracy of measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0058] Figure 1 Schematic diagram of the structure of the eddy current displacement sensor provided in the embodiment of the present application Figure 1 ;

[0059] Figure 2 Schematic diagram of the structure of the eddy current displacement sensor provided in the embodiment of the present application Figure 2 ;

[0060] Figure 3 Schematic diagram of the process of the temperature drift compensation method provided in the embodiment of the present application Figure 1 ;

[0061] Figure 4 A schematic diagram of the linear relationship between the compensation output signal and temperature provided in an embodiment of the present application;

[0062] Figure 5 This is a schematic diagram of measurement results before using the temperature drift compensation method provided in an embodiment of the present application;

[0063] Figure 6 A schematic diagram of measurement results after using the temperature drift compensation method provided in an embodiment of the present application;

[0064] Figure 7 Schematic diagram of the process of the temperature drift compensation method provided in the embodiment of the present application Figure 2 ;

[0065] Figure 8 A schematic diagram of the structure of a temperature drift compensation device provided in an embodiment of the present application;

[0066] Figure 9 This is a schematic diagram of the hardware structure of the electronic device provided in this application.

[0067] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments.

[0068] Reference numerals:

[0069] 101: measuring coil; 102: metal partition; 103: compensation coil; 104: insulation layer; 105: metal pressing sheet; 106: frame body; 107: metal probe protective cover; 108: lead wire. DETAILED DESCRIPTION

[0070] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0071] It should be noted that the eddy current displacement sensor and temperature drift compensation method provided in this application can be used in the field of displacement sensor technology, and can also be used in any field other than the field of displacement sensor technology. The application fields of the eddy current displacement sensor and temperature drift compensation method provided in this application are not limited.

[0072] Eddy current displacement sensor is a non-contact measuring device based on the principle of electromagnetic induction. It is widely used in industrial automation, aerospace, energy and other fields to measure parameters such as displacement, vibration, and deformation of metal conductors.

[0073] In related technologies, eddy current displacement sensors include a sensor coil. They operate by generating an alternating magnetic field in the sensor coil through a high-frequency alternating current. When a metal conductor under test approaches the coil, eddy currents are induced within the conductor. The magnetic field generated by these eddy currents interacts with the magnetic field of the sensor coil, thereby changing parameters such as the impedance of the sensor coil. By detecting changes in the impedance of the sensor coil and other parameters, the distance between the metal conductor under test and the eddy current displacement sensor can be indirectly measured.

[0074] However, the performance of the above-mentioned eddy current displacement sensor is significantly reduced in harsh environments such as high temperature, high humidity, and radiation, and its adaptability is poor.

[0075] In order to solve the above technical problems, the inventors of the present application have found that the shell of the eddy current displacement sensor in the related art is usually made of plastic or non-metallic materials, which are prone to deformation or aging in harsh environments such as high temperature, thereby reducing the performance of the sensor, affecting its service life and reliability, and being unable to adapt to harsh environments. In addition, in a high temperature environment, the resistance of the sensor coil increases, the magnetic permeability of the coil material changes, and the conductivity and magnetic permeability of the measured metal conductor also change with temperature. The combined effect of these factors causes the sensor output signal to produce temperature drift in harsh environments such as high temperature, thereby increasing the measurement error and degrading performance. Therefore, the inventors of the present application set a metal probe protective cover on the probe, and by setting a measuring coil and a compensation coil, the measuring coil and the compensation coil produce the same changes with temperature, thereby achieving hardware compensation for temperature drift, so that the eddy current displacement sensor improves its adaptability to harsh environments. Based on this, the embodiment of the present application provides an eddy current displacement sensor.

[0076] The following specific embodiments are used to describe the technical solution of the present application in detail. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0077] Figure 1 Schematic diagram of the structure of the eddy current displacement sensor provided in the embodiment of the present application Figure 1 .like Figure 1As shown, the eddy current displacement sensor includes: a probe, a cable and a preamplifier; the probe includes a metal probe protective cover 107, and a measuring coil 103, a metal partition 102, a compensation coil 101, a metal pressing plate 105 and a skeleton 106 arranged in the metal probe protective cover 107; the measuring coil 103, the metal partition 102, the compensation coil 101 and the metal pressing plate 105 are sequentially arranged on the skeleton 106; the first end of the compensation coil 101 and the first end of the measuring coil 103 are both connected to the preamplifier; the second end of the compensation coil 101 and the second end of the measuring coil 103 are both connected to a first common end; the metal partition 102 is used to isolate the measuring coil 103 and the compensation coil 101 to prevent the eddy current generated on the test piece from affecting the parameters of the compensation coil 101; The metal pressing plate 105 is used to fix the position of the compensation coil 101 and is symmetrical with the front end of the metal probe protective cover 107 relative to the metal partition 102, so that the compensation coil 101 and the measuring coil 103 change in the same manner as the temperature changes. The measuring coil 103 is used to generate eddy currents on the surface of the test piece, generating different impedances under the influence of different eddy currents, and is also used to serve as the first arm of the bridge circuit to output a measurement signal. The magnitude of the eddy current is related to the distance between the measuring coil 103 and the test piece. The compensation coil 101 is used to change synchronously with the measuring coil 103 in response to temperature changes and is also used to serve as the second arm of the bridge circuit to output a compensation signal. The preamplifier is used to perform differential processing on the measurement signal and the compensation signal to obtain distance information. The sensor provided in this embodiment has multiple beneficial effects. First, by introducing a metal partition 102 into the probe, the measuring coil 103 and the compensation coil 101 are effectively isolated, preventing the eddy currents generated by the test piece from affecting the compensation coil 101, thereby improving measurement accuracy. Secondly, the metal pressing plate 105 is used to fix the position of the compensation coil 101 and forms a symmetrical structure with the metal probe protective cover 107, ensuring that the compensation coil 101 and the measuring coil 103 have the same response to temperature changes. This design ensures that the compensation coil 101 and the measuring coil 103 change synchronously when the temperature changes, thereby achieving effective temperature drift compensation and further improving measurement accuracy and stability. In addition, the measuring coil 103 and the compensation coil 101 serve as the bridge arms of the bridge circuit, respectively, capable of outputting a measurement signal and a compensation signal. The preamplifier performs differential processing on these two signals, eliminating errors caused by environmental factors and temperature changes, and directly obtaining distance information. This differential processing method improves the system's anti-interference capability and signal processing accuracy.Overall, the sensor has a reasonable structural design and can provide high-precision displacement measurement in complex environments. It is suitable for various industrial application scenarios, especially in environments with high temperatures or large temperature fluctuations, ensuring the reliability and accuracy of the measurement results.

[0078] In this embodiment, the metal probe protection cover 107 is a full-metal probe protection cover 107. By making the metal probe protection cover entirely of metal, it is less likely to deform or age, thereby ensuring the performance of the probe.

[0079] In this embodiment, Figure 1 As shown, the eddy current displacement sensor may further include an insulating layer 104 .

[0080] In some embodiments, the probe further includes: a first insulating layer disposed between the measuring coil and the metal partition, and a second insulating layer disposed between the metal partition and the compensation coil; the first insulating layer is part of the skeleton, and / or the second insulating layer is part of the skeleton; the first insulating layer is used to insulate the measuring coil from the metal partition; and the second insulating layer is used to insulate the compensation coil from the metal partition. The sensor provided in this embodiment, by providing the insulating layer, can ensure insulation between the measuring coil and the metal partition, and insulation between the compensation coil and the metal partition, thereby ensuring the accuracy of the compensation signal and the measurement signal, thereby ensuring the effectiveness of temperature drift compensation and the accuracy of distance measurement.

[0081] For example, Figure 2 As shown, the first insulating layer may be the raised portion of the skeleton 106 , and the second insulating layer may be the insulating layer 104 .

[0082] The eddy current displacement sensor includes a probe, a cable, and a preamplifier. The probe includes a measuring coil 101, a metal partition 102, a compensation coil 103, an insulating layer 104, a metal pressing sheet 105, a frame 106, a metal probe protective cover 107, and a lead 108.

[0083] The measuring coil 101 , the metal partition 102 , the compensation coil 103 , the insulating layer 104 and the metal pressing sheet 105 are sequentially sleeved on the frame body 106 .

[0084] Arranged from the front end of the probe (the end closest to the test piece) to the back end are: measuring coil 101, the insulating layer of the frame 106, metal spacer 102, insulating layer 104, compensation coil 103, and metal pressing plate 105. The coil leads 108 are led out from the back end of the probe. All components of the probe, except for the metal probe protective cover 107, are enclosed within the metal probe protective cover 107, forming a fully metal sealed structure.

[0085] Among them, the measuring coil 101 is used to flow high-frequency alternating current to generate an alternating magnetic field. When the test piece approaches, it interacts with the magnetic field generated by the eddy current of the test piece to change the impedance value; the eddy current is generated by the test piece under the action of the alternating magnetic field.

[0086] The metal partition 102 is used to isolate the measuring coil 101 and the compensation coil 103 to prevent the eddy current signal generated in the test piece from affecting the parameter change of the compensation coil.

[0087] Compensation coil 103, used for temperature drift compensation, forms a bridge circuit with measuring coil 101. Specifically, the principle of temperature drift compensation is that the two signals sensed by the measuring coil and the compensation coil are processed by the bridge circuit and subsequent circuits and then connected to the differential input terminals of the amplifier. Through differential calculation, changes in signal amplitude caused by changes in coil parameters due to temperature changes are offset, thereby ensuring that the measurement results are not affected by temperature and achieving temperature drift compensation.

[0088] The insulating layer 104 is used to ensure that insulation is maintained between the compensation coil 103 and the metal partition 102. The magnetic permeability and electrical conductivity of the material of the metal partition 102 are both greater than the corresponding preset values, so that the magnetic permeability and electrical conductivity of the metal partition 102 are high enough to cope with harsh environments. The temperature resistance and hardness of the insulating layer 104 are both greater than the corresponding preset values, so that the insulating layer 104 has high temperature resistance and strong hardness; the size, thickness and other parameters of the metal partition 102 and the insulating layer 104 can be designed accordingly according to the size specifications of the probe, and this embodiment does not limit this. The raised portion of the skeleton body 106 serves as another insulating layer to ensure that insulation is maintained between the measuring coil 101 and the metal partition 102.

[0089] The metal pressing plate 105 is used to fix the position of the compensation coil. The front ends of the metal pressing plate 105 and the metal probe protective cover 107 form a symmetrical design relative to the metal partition 102 located between the two, thereby achieving synchronous changes in the signals of the measuring coil 101 and the compensation coil 103 when the temperature changes, thereby improving the effect of temperature drift compensation.

[0090] The frame body 106 is used to support and fix other internal components of the probe except the frame body 106, such as the measuring coil 101, the metal partition 102, the compensation coil 103, the insulating layer 104, the metal pressing sheet 105 and the like.

[0091] The metal probe protection cover 107 is made of all-metal material to form a sealed structure, which enhances the performance of high temperature resistance, high humidity and radiation resistance.

[0092] In some embodiments, the preamplifier includes: a third bridge arm and a fourth bridge arm of a bridge circuit, a compensation channel, a measurement channel, an amplifier, and a microprocessor; the first end of the third bridge arm and the first end of the second bridge arm are connected to the input end of the compensation channel, and the first end of the fourth bridge arm and the first end of the first bridge arm are connected to the input end of the measurement channel; the output end of the compensation channel is connected to the first input end of the amplifier, and the output end of the measurement channel is connected to the second input end of the amplifier; the output end of the amplifier is connected to the microprocessor; the compensation channel is used to process the compensation signal to obtain a compensation output signal; the measurement channel is used to process the measurement signal to obtain a measurement output signal; the amplifier is used to perform differential processing on the compensation output signal and the measurement output signal to obtain a differential signal; and the microprocessor is used to determine distance information based on the differential signal. The sensor provided in this embodiment, by providing a compensation channel and a measurement channel, can process the compensation signal and the measurement signal separately, and then obtain a differential signal between the compensation signal and the measurement signal through the amplifier, thereby eliminating errors caused by temperature changes, achieving temperature drift compensation, and improving the accuracy of distance measurement.

[0093] In some embodiments, the cable is a two-core shielded cable; the third bridge arm includes: a first resistor and a first capacitor; the fourth bridge arm includes: a second resistor and a second capacitor; the preamplifier also includes an excitation signal generator; the shielded end of the cable is connected to the first common end and grounded; the first end of the first capacitor is connected to the compensation coil through the first core wire of the cable, the first end of the second capacitor is connected to the measuring coil through the second core wire of the cable, the second end of the first capacitor is connected to the second common end through the first resistor, the second end of the second capacitor is connected to the second common end through the second resistor, and the second common end is connected to the excitation signal generator; the excitation signal generator is used to provide an excitation signal for the bridge circuit. The sensor provided in this embodiment can effectively reduce electromagnetic interference and improve signal transmission stability by using a two-core shielded cable for grounding. The combination of resistors and capacitors in the bridge circuit, combined with the excitation signal provided by the excitation signal generator, can achieve accurate processing of the compensation coil and measuring coil signals, balance the bridge arm impedance, and thereby improve the measurement accuracy and anti-interference ability of the sensor.

[0094] In some embodiments, the compensation channel and the measurement channel are symmetrically arranged; the compensation channel includes: a first high-pass filter, a first buffer, and a first low-pass filter connected in sequence; the measurement channel includes: a second high-pass filter, a second buffer, and a second low-pass filter connected in sequence; the first high-pass filter is used to filter the noise signal in the output signal corresponding to the compensation coil to obtain a first high-pass signal; the first buffer is used to drive the first high-pass signal to obtain a first drive signal; the first low-pass filter is used to perform AC-DC conversion on the first drive signal to obtain the compensation output signal; the second high-pass filter is used to filter the noise signal in the output signal corresponding to the measurement coil to obtain a second high-pass signal; the second buffer is used to drive the second high-pass signal to obtain a second drive signal; and the second low-pass filter is used to perform AC-DC conversion on the second drive signal to obtain the measurement output signal. The sensor provided in this embodiment achieves high efficiency and accuracy in signal processing by symmetrically arranging the compensation channel and the measurement channel. Specifically, the compensation channel and the measurement channel both include a combination structure of a high-pass filter, a buffer, and a low-pass filter. The high-pass filter effectively filters noise signals, improving signal purity; the buffer provides signal drive capability, ensuring stable signal transmission; and the low-pass filter performs AC-DC conversion, resulting in a stable output signal. This structural design enables accurate signal measurement and compensation in complex electromagnetic environments, improving overall system performance and reliability.

[0095] In some embodiments, the amplifier includes an instrumentation amplifier and a proportional amplifier. The first input of the instrumentation amplifier is connected to the output of the compensation channel, and the second input of the instrumentation amplifier is connected to the output of the measurement channel. The input of the proportional amplifier is connected to the output of the instrumentation amplifier, and the output of the proportional amplifier is connected to the microprocessor. The instrumentation amplifier is configured to differentially amplify the compensation output signal and the measurement output signal to obtain an initial differential signal. The proportional amplifier is configured to proportionally amplify the initial differential signal to obtain a target differential signal. The microprocessor is configured to process the target differential signal to obtain the distance information. The sensor provided in this embodiment achieves high-precision and high-reliability signal processing by incorporating the instrumentation amplifier and the proportional amplifier. The instrumentation amplifier differentially amplifies the compensation output signal and the measurement output signal, effectively eliminating common-mode noise and improving signal accuracy. Its high input impedance and high common-mode rejection ratio ensure signal integrity. The proportional amplifier then proportionally amplifies the initial differential signal, further increasing the signal amplitude and enabling more accurate subsequent processing. Finally, the microprocessor processes the target differential signal to obtain accurate distance information. This design structure not only improves the signal amplification accuracy, but also enhances the system's ability to suppress noise, ensuring the reliability and accuracy of the measurement results.

[0096] In some embodiments, the preamplifier further includes a half-wave rectifier; the input of the half-wave rectifier is connected to the output of the compensation coil, and the output of the half-wave rectifier is connected to the output of the instrumentation amplifier and the input of the proportional amplifier; the half-wave rectifier is configured to extract the DC component of the output signal corresponding to the compensation coil and compensate the initial differential signal based on the DC component. The sensor provided in this embodiment further enhances the accuracy and stability of signal processing by introducing a half-wave rectifier into the preamplifier. The half-wave rectifier is configured to extract the DC component of the output signal of the compensation coil and use this DC component to compensate the initial differential signal. This process effectively eliminates low-frequency noise and offset errors in the signal, thereby improving signal purity and accuracy. By accurately extracting and compensating the DC component, the system can better adapt to different operating environments and conditions, ensuring the stability and reliability of measurement results. Furthermore, this structure simplifies the complexity of subsequent signal processing, improving the efficiency and performance of the overall system.

[0097] In some embodiments, the preamplifier further includes: a voltage-to-current converter; the voltage-to-current converter is connected to the microprocessor and is used to convert the voltage signal corresponding to the distance information to obtain a current signal corresponding to the distance information. The sensor provided in this embodiment improves the signal transmission efficiency and anti-interference capability of the system by integrating the voltage-to-current converter in the preamplifier. The voltage-to-current converter converts the voltage signal corresponding to the distance information into a current signal. This conversion helps to reduce signal attenuation and interference during long-distance transmission. Compared with voltage signals, current signals are less susceptible to electromagnetic interference, thereby improving the stability and reliability of signal transmission. In addition, through current signal transmission, signal errors caused by changes in cable resistance can be effectively reduced, ensuring the accuracy of distance information during transmission. This not only optimizes the signal transmission quality, but also enhances the system's adaptability in complex environments, improving the performance and reliability of the overall measurement system.

[0098] For example, Figure 2 As shown, the cable can be a two-core shielded cable, which is used to connect the probe and the preamplifier.

[0099] Among them, one end of the measuring coil 101 and one end of the compensating coil 103 are connected to form a common end, which is connected to the shielding end of the cable; the other end of the measuring coil 101 is connected to one of the two core wires of the cable, and the other end of the compensating coil 103 is connected to the other of the two core wires.

[0100] The preamplifier includes the third and fourth arms of the bridge circuit, an excitation signal generator (such as a square wave generator), a high-pass filter (HPF), a buffer and a low-pass filter (LPF) of the compensation channel and the measurement channel, a half-wave rectifier, an instrumentation amplifier, a proportional amplifier (such as an adding proportional amplifier), a voltage-to-current converter, and a microprocessor.

[0101] The bridge circuit includes the probe's measuring coil 101 and compensating coil 103, as well as resistors (R1 and R2) and capacitors (C1 and C2). The measuring coil 101 serves as the first arm of the bridge circuit, the compensating coil 103 serves as the second arm, the resistor R1 and capacitor C1 serve as the third arm, and the resistor R2 and capacitor C3 serve as the fourth arm. The node between the third and fourth arms (i.e., the common end between the measuring coil 101 and the compensating coil 103) is connected to a square wave generator. The node between the second and third arms (i.e., the common end between capacitor C1 and the compensating coil) is grounded via capacitor C3. The node between the first and fourth arms (i.e., the common end between capacitor C2 and the measuring coil) is grounded via capacitor C4.

[0102] The bridge circuit is used to sense the strength of the eddy current signal generated on the test piece, so as to detect displacement changes and temperature drift based on the strength of the eddy current signal.

[0103] The square wave generator is used to provide an excitation signal to the bridge circuit to drive the bridge circuit to work.

[0104] The first bridge arm node is connected to the HPF, which is used to filter out low-frequency noise in the signal output by the bridge circuit to ensure the accuracy of subsequent signal processing.

[0105] The signal output by the HPF is buffered by a buffer, which is used to improve the driving capability of the signal and reduce the attenuation of the signal during transmission.

[0106] The signal output by the buffer is filtered by an LPF, which is used to convert the AC signal into a DC signal for subsequent processing.

[0107] The signals output by the LPF are respectively connected to the two input terminals of the instrumentation amplifier, which is used to amplify the signals output by the bridge circuit.

[0108] The input end of the compensation channel is connected to the input end of the half-wave rectifier, and the output end of the half-wave rectifier is connected to the output end of the instrumentation amplifier. The half-wave rectifier is used to extract the DC component in the second signal output by the bridge circuit. The DC component is used for temperature drift compensation. The output signal of the half-wave rectifier and the output signal of the instrumentation amplifier are sent to the proportional amplifier together. The proportional amplifier is used to further proportionally amplify the signal amplified by the instrumentation amplifier to meet the requirements of subsequent processing.

[0109] The output signal of the proportional amplifier and the output signal of the compensation channel's LPF are connected to the microprocessor's input terminal AD. The microprocessor is used to convert the signal input to the AD terminal through its internal analog-to-digital converter, thereby controlling the operation of the entire system and performing software compensation for temperature drift based on the collected input signal. The microprocessor is also used to generate an analog signal through its internal digital-to-analog converter and control the output terminal DA to output this analog signal for subsequent processing.

[0110] The output end of the microprocessor is connected to the input end of the voltage-to-current converter. The voltage-to-current converter is used to convert the voltage signal output by the microprocessor into a current signal as distance information to meet the needs of practical applications.

[0111] In some embodiments, the eddy current sensor is suitable for a working environment that meets at least one of the following conditions: temperature less than or equal to 260°C, humidity less than or equal to 100%, and radiation dose less than or equal to 100kGy. The sensor provided in this embodiment is designed to be suitable for specific harsh working environments, which significantly expands its application range and reliability. First, it can operate under conditions of temperature less than or equal to 260°C, making the sensor suitable for high-temperature industrial environments, such as metal processing and aerospace. Secondly, it supports operation in environments with humidity less than or equal to 100%, ensuring that the sensor can maintain stable performance under high humidity or humid conditions, which is crucial for chemical and marine applications. In addition, it can withstand radiation doses less than or equal to 100kGy, which means that the sensor can still operate reliably in high-radiation environments, such as nuclear industry or medical radiation equipment. These characteristics together improve the adaptability and durability of eddy current sensors in extreme environments, ensuring that they can still provide accurate and stable measurement results under a variety of harsh conditions.

[0112] Although when there is no test piece at the front end of the probe or it is far away from the test piece, the temperature drift compensation is realized by hardware design, so that the temperature drift problem of the eddy current sensor has been improved, but as the test piece gradually approaches the probe, the eddy current effect is enhanced. Since the temperature rise causes the conductivity of the conductor of the test piece to increase, the eddy current is weakened instead. This phenomenon is equivalent to the distance between the probe and the test piece increasing when the temperature rises, thereby causing the change of the output current, that is, the temperature drift reappears. It is worth noting that the closer the probe is to the test piece, the more significant the change in the output current. Since this temperature drift cannot be completely solved by hardware, the present application also provides a temperature drift compensation method, which uses a software algorithm to perform temperature drift compensation to achieve more stable measurement results.

[0113] Figure 3 Schematic diagram of the process of the temperature drift compensation method provided in the embodiment of the present application Figure 1 .like Figure 3 As shown, the method includes:

[0114] 301. Obtain a compensation output signal output by a compensation channel and a differential signal output by the amplifier.

[0115] The execution entity of this embodiment can be Figure 2 The microprocessor and other electronic devices shown.

[0116] For example, Figure 4 As shown, the compensation output signal output by the compensation channel (i.e. Figure 2 The voltage of the LPF output of the compensation channel shown in FIG. 1 decreases as the temperature increases, and the voltage changes linearly with the temperature. Therefore, the temperature value can be estimated based on the voltage value of the voltage without adding an additional temperature sensor.

[0117] 302. Determine the current temperature based on the compensated output signal and a preset correspondence, and determine a correction value corresponding to the compensated output signal based on the current temperature; the preset correspondence includes a one-to-one correspondence between the voltage values of multiple compensated output signals and multiple temperatures, and a one-to-one correspondence between multiple temperatures and multiple correction values.

[0118] Specifically, a preset correspondence can be established and stored first. For example, 5 temperature points can be selected, and the output voltage of the LPF of the compensation channel (i.e., the compensation output signal) can be collected every 100 microns within the measurement range of 0 to 1 mm at each temperature. The collected data is used to establish a relationship model between the temperature and the output voltage of the LPF of the compensation channel (i.e., the preset correspondence), and the correction data at different temperatures and positions are calculated and stored. In actual use, the collected LPF output voltage of the compensation channel can be substituted into the relationship model, and the temperature of the probe temperature field can be determined based on the relationship model.

[0119] 303. Determine an initial distance according to the differential signal.

[0120] 304. Correct the initial distance according to the correction value to obtain the distance information.

[0121] Specifically, the distance d between the probe and the device under test (i.e., the initial distance) is estimated based on the collected differential signal and corrected using the correction data to achieve temperature drift compensation. This eliminates the need for an additional temperature sensor to measure temperature, reducing the size of the probe.

[0122] The following combination Figure 5 and Figure 6 The effects before and after using the above temperature drift compensation method are compared and explained. Figure 5 As shown in Figure 1, due to the above hardware compensation measures, when the distance d is far, the temperature drift of the sensor output current is small. As the distance d becomes smaller, the temperature drift of the sensor output current increases. Figure 6 As shown in the figure, after temperature drift compensation, the output current of the sensor remains stable at different temperatures, which significantly improves the measurement accuracy.

[0123] The temperature drift compensation method provided in this embodiment realizes temperature estimation and temperature drift compensation of distance measurement by utilizing the linear relationship between the voltage signal output by the compensation channel and the temperature, which has multiple beneficial effects. First, by directly using the compensation output signal to estimate the temperature, there is no need to add an additional temperature sensor, which simplifies the system design, reduces costs, and reduces the volume of the probe. This is particularly important for application scenarios that require miniaturization and lightweighting. Secondly, by presetting the corresponding relationship and correction value, the system can automatically perform temperature drift compensation for distance measurement under different temperature conditions, thereby improving measurement accuracy and reliability. Finally, the method implements temperature drift compensation through software, avoids the increase of hardware complexity, and enhances the flexibility and adaptability of the system. This design not only optimizes the performance of the sensor, but also expands its applicability in a variety of industrial and scientific applications, especially in environments with significant temperature changes.

[0124] In some embodiments, as Figure 2 and Figure 7 As shown, the temperature drift compensation method may include the following steps: collecting the output voltage of the LPF in the compensation channel and the output voltage of the proportional amplifier; establishing a relationship model between temperature and the LPF output voltage; calculating correction data at different temperatures and positions and storing it in a microprocessor. In actual use, the temperature of the probe temperature field is calculated based on the relationship model and the current output voltage of the LPF in the compensation channel; and the distance d between the probe and the test device is estimated based on the output voltage of the proportional amplifier. Combined with the correction data, the DAC outputs a corrected voltage value to achieve temperature drift compensation.

[0125] Figure 8 This is a schematic diagram of the structure of the temperature drift compensation device provided in the embodiment of the present application. Figure 8 As shown, the eddy current displacement sensor device 80 includes: an acquisition module 801 , a determination module 802 , a processing module 803 and a correction module 804 .

[0126] The acquisition module 801 is configured to acquire the compensation output signal output by the compensation channel and the differential signal output by the amplifier.

[0127] Determination module 802 is used to determine the current temperature based on the compensated output signal and a preset correspondence, and determine the correction value corresponding to the compensated output signal based on the current temperature; the preset correspondence includes a one-to-one correspondence between the voltage values of multiple compensated output signals and multiple temperatures, and a one-to-one correspondence between multiple temperatures and multiple correction values.

[0128] The processing module 803 is configured to determine an initial distance according to the differential signal.

[0129] The correction module 804 is configured to correct the initial distance according to the correction value to obtain the distance information.

[0130] The eddy current displacement sensor device provided in the embodiment of the present application realizes temperature estimation and temperature drift compensation of distance measurement by utilizing the linear relationship between the voltage signal output by the compensation channel and the temperature, which has multiple beneficial effects. First, by directly using the compensation output signal to estimate the temperature, there is no need to add an additional temperature sensor, which simplifies the system design, reduces costs, and reduces the volume of the probe. This is particularly important for application scenarios that require miniaturization and lightweighting. Secondly, by presetting the corresponding relationship and correction value, the system can automatically perform temperature drift compensation for distance measurement under different temperature conditions, thereby improving measurement accuracy and reliability. Finally, the method implements temperature drift compensation through software, avoids the increase of hardware complexity, and enhances the flexibility and adaptability of the system. This design not only optimizes the performance of the sensor, but also expands its applicability in a variety of industrial and scientific applications, especially in environments with significant temperature changes.

[0131] Figure 9 This is a schematic diagram of the hardware structure of the electronic device provided in this application. Figure 9 As shown, the electronic device 90 provided in this embodiment includes: at least one processor 901 and a memory 902. Optionally, the electronic device 90 further includes a communication component 903. The processor 901, the memory 902 and the communication component 903 are connected via a bus.

[0132] During the specific implementation process, at least one processor 901 executes the computer-executable instructions stored in the memory 902, so that the at least one processor 901 performs the above method.

[0133] The specific implementation process of the processor 901 can be found in the above method embodiment. Its implementation principle and technical effects are similar and will not be repeated here in this embodiment.

[0134] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASICs), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the present invention may be directly executed by a hardware processor or by a combination of hardware and software modules in the processor.

[0135] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (NVM), such as at least one disk memory.

[0136] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. Buses can be classified into address buses, data buses, and control buses. For ease of illustration, the buses in the drawings of this application are not limited to just one bus or just one type of bus.

[0137] The present application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0138] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above method is implemented.

[0139] The above-mentioned readable storage medium can be implemented by any type of volatile or non-volatile memory device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0140] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist in a device as discrete components.

[0141] The division of units is merely a logical functional division; actual implementations may employ alternative divisions, such as combining or integrating multiple units or components into another system, or omitting or disabling certain features. Furthermore, any direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units, either through an interface, electrical, mechanical, or other means.

[0142] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0143] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0144] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0145] Those skilled in the art will appreciate that all or part of the steps in the above-described method embodiments can be implemented using hardware associated with program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0146] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. An eddy current displacement sensor, characterized in that: include: Probes, cables and preamplifiers; The probe includes a metal probe protective cover, and a measuring coil, a metal partition, a compensation coil, a metal pressing sheet and a frame body arranged in the metal probe protective cover; the measuring coil, the metal partition, the compensation coil and the metal pressing sheet are arranged on the frame body in sequence; The first end of the compensation coil and the first end of the measuring coil are both connected to the proximitor; the second end of the compensation coil and the second end of the measuring coil are both connected to a first common end; The metal partition is used to isolate the measuring coil and the compensation coil; The metal pressing sheet is used to fix the position of the compensation coil and is symmetrical with the front end of the metal probe protective cover relative to the metal partition, so that the compensation coil and the measuring coil change in the same way as the temperature changes; The measuring coil is used to generate eddy currents on the surface of the test object, generate different impedances under the influence of different eddy currents, and is also used to serve as the first arm of the bridge circuit to output a measurement signal; the magnitude of the eddy current is related to the distance between the measuring coil and the test object; The compensation coil is used to change synchronously with the measuring coil in response to temperature changes, and is also used to serve as the second arm of the bridge circuit to output a compensation signal; The preamplifier is used to perform differential processing on the measurement signal and the compensation signal to obtain distance information.

2. The eddy current displacement sensor according to claim 1, characterized in that: The probe further includes: a first insulating layer provided between the measuring coil and the metal partition, and a second insulating layer provided between the metal partition and the compensation coil; the first insulating layer is part of the frame body, and / or the second insulating layer is part of the frame body; The first insulating layer is used to maintain insulation between the measuring coil and the metal partition; The second insulating layer is used to maintain insulation between the compensation coil and the metal separator.

3. The eddy current displacement sensor according to claim 1, characterized in that: The preamplifier includes: a third bridge arm and a fourth bridge arm of the bridge circuit, a compensation channel, a measurement channel, an amplifier and a microprocessor; The first end of the third bridge arm and the first end of the second bridge arm are connected to the input end of the compensation channel, and the first end of the fourth bridge arm and the first end of the first bridge arm are connected to the input end of the measurement channel; The output end of the compensation channel is connected to the first input end of the amplifier, and the output end of the measurement channel is connected to the second input end of the amplifier; the output end of the amplifier is connected to the microprocessor; The compensation channel is used to process the compensation signal to obtain a compensation output signal; The measurement channel is used to process the measurement signal to obtain a measurement output signal; The amplifier is used to perform differential processing on the compensation output signal and the measurement output signal to obtain a differential signal; The microprocessor is used to determine distance information according to the differential signal.

4. The eddy current displacement sensor according to claim 3, characterized in that: The cable is a two-core shielded cable; The third bridge arm includes: a first resistor and a first capacitor; the fourth bridge arm includes: a second resistor and a second capacitor; the preamplifier also includes an excitation signal generator; The shield end of the cable is connected to the first common end and is grounded; the first end of the first capacitor is connected to the compensation coil through the first core wire of the cable, the first end of the second capacitor is connected to the measuring coil through the second core wire of the cable, the second end of the first capacitor is connected to the second common end through the first resistor, the second end of the second capacitor is connected to the second common end through the second resistor, and the second common end is connected to the excitation signal generator; The excitation signal generator is used to provide an excitation signal for the bridge circuit.

5. The eddy current displacement sensor according to claim 3, characterized in that: The compensation channel and the measurement channel are symmetrically arranged; the compensation channel comprises: a first high-pass filter, a first buffer and a first low-pass filter connected in sequence; the measurement channel comprises: a second high-pass filter, a second buffer and a second low-pass filter connected in sequence; The first high-pass filter is used to filter the noise signal in the output signal corresponding to the compensation coil to obtain a first high-pass signal; The first buffer is configured to drive the first high-pass signal to obtain a first driving signal; The first low-pass filter is configured to perform AC-DC conversion on the first driving signal to obtain the compensated output signal; The second high-pass filter is used to filter the noise signal in the output signal corresponding to the measuring coil to obtain a second high-pass signal; The second buffer is configured to drive the second high-pass signal to obtain a second driving signal; The second low-pass filter is used to perform AC-DC conversion on the second driving signal to obtain the measurement output signal.

6. The eddy current displacement sensor according to claim 3, characterized in that: The amplifier includes: an instrument amplifier and a proportional amplifier; The first input terminal of the instrumentation amplifier is connected to the output terminal of the compensation channel, and the second input terminal of the instrumentation amplifier is connected to the output terminal of the measurement channel; the input terminal of the proportional amplifier is connected to the output terminal of the instrumentation amplifier, and the output terminal of the proportional amplifier is connected to the microprocessor; The instrumentation amplifier is configured to differentially amplify the compensation output signal and the measurement output signal to obtain an initial differential signal; The proportional amplifier is used to proportionally amplify the initial differential signal to obtain a target differential signal; The microprocessor is used to process the target differential signal to obtain the distance information.

7. The eddy current displacement sensor according to claim 6, characterized in that: The preamplifier further includes: a half-wave rectifier; The input end of the half-wave rectifier is connected to the output end of the compensation coil, and the output end of the half-wave rectifier is connected to the output end of the instrumentation amplifier and the input end of the proportional amplifier; The half-wave rectifier is used to extract the DC component of the output signal corresponding to the compensation coil, and compensate the initial differential signal according to the DC component.

8. The eddy current displacement sensor according to claim 3, characterized in that: The preamplifier further includes: a voltage-to-current converter; The voltage-to-current converter is connected to the microprocessor and is used to convert the voltage signal corresponding to the distance information to obtain the current signal corresponding to the distance information.

9. The eddy current displacement sensor according to any one of claims 1 to 8, characterized in that: The applicable working environment meets at least one of the following conditions: temperature less than or equal to 260°C, humidity less than or equal to 100%, and radiation dose less than or equal to 100 kGy.

10. A temperature drift compensation method, applied to the eddy current displacement sensor according to any one of claims 3 to 8, characterized in that: The method comprises: Obtaining a differential signal between a compensation output signal output by the compensation channel and an amplifier output; Determining a current temperature based on the compensated output signal and a preset correspondence relationship, and determining a correction value corresponding to the compensated output signal based on the current temperature; the preset correspondence relationship includes a one-to-one correspondence between voltage values of multiple compensated output signals and multiple temperatures, and a one-to-one correspondence between multiple temperatures and multiple correction values; determining an initial distance according to the differential signal; The initial distance is corrected according to the correction value to obtain the distance information.

Images