Differential eddy current displacement sensor calibration device and calibration method thereof

Abstract

The invention discloses a differential eddy current displacement sensor calibration device and a calibration method thereof, and relates to the technical field of sensors, the device comprises a fixing device, a detection assembly and an adjusting device, and the adjusting device and the detection assembly are installed on the fixing device; the detection assembly comprises a first detection assembly and a second detection assembly, the first detection assembly comprises a first support and a first sensor probe, the second detection assembly comprises a second support and a second sensor probe, the first sensor probe is fixedly installed on one side of a detected object, and the movable second sensor probe is installed on the other side of the detected object. The distance between the second probe of the sensor and the measured object is controlled by adjusting the micrometer fine adjustment sliding table, so that the distance accurately reaches the zero clearance required by the calibration device, and meanwhile, the measured object is stepped by using the high-precision digital display ten-thousand-meter ruler, so that the calibration result is more accurate, and the calibration precision is improved.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a calibration device and a calibration method for a differential eddy current displacement sensor. Background Art

[0002] As a non-contact, high-precision micro-displacement measuring element, eddy current sensors are widely used in the measurement of physical quantities such as displacement, vibration, rotation speed, metal film thickness, geometric dimensions of metal components, surface roughness, etc., with the advantages of simple structure, low price, high sensitivity, wide frequency band, no influence of oily media, and strong anti-interference ability. They play an important role in industrial production, aviation industry, nuclear industry, petrochemical industry, safety detection and other fields. Eddy current sensors are divided into single-ended and differential types. Single-ended eddy current displacement sensors are used in occasions where linearity is not high. If the linearity requirement is high, two probes can be used for differential measurement.

[0003] The calibration of differential eddy current displacement sensor is the key to the practical application of the sensor. The accuracy of the sensor calibration curve directly affects the accuracy of the sensor's displacement measurement. Before the differential eddy current sensor is actually applied, the sensor must be calibrated. The first step of the calibration is to install and fix the first sensor probe, the second sensor probe and the object to be measured so that they can reach the relative position required by the system. When the sensor output voltage is zero, the gap between the first sensor probe, the second sensor probe and the object to be measured is called the zero gap. First, the first sensor probe is installed and fixed, and the object to be measured is translated by adjusting the high-precision digital micrometer to make the first sensor probe reach the zero gap position; for the zero gap installation position of the second sensor probe required by the system, the traditional practice in the past is usually to manually adjust the position of the second sensor probe so that the distance between the second sensor probe and the object to be measured changes, and simultaneously observe the sensor output voltage until the deviation between the sensor output voltage and the zero voltage is within the allowable range, and then the second sensor probe is fixed and installed. After the first sensor probe and the second sensor probe reach the specified zero gap, the object to be measured is adjusted multiple times to obtain multiple sets of corresponding relationships between the distance between the object to be measured and the sensor probe and the output voltage value of the sensor, and finally the calibration curve of the differential eddy current displacement sensor is obtained by data fitting. In this method, it is very difficult to manually adjust the second sensor probe to the zero gap position, which reduces the calibration efficiency. In order to improve the calibration accuracy and efficiency of the differential eddy current displacement sensor, a calibration device and method are urgently needed. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The purpose of the present invention is to solve the problem that when calibrating a differential eddy current displacement sensor, it is necessary to install and fix the first probe of the sensor, the second probe of the sensor and the object to be measured so that they reach the relative position required by the system, and it is difficult to manually adjust the second probe of the sensor to the zero gap position, with large errors and low efficiency. The patent of the present invention proposes to install the second probe of the sensor on a manually adjustable adjustment device, and adjust the micrometer fine-tuning slide on the adjustment device to drive the second probe of the sensor so that it can move forward and backward accurately with a step resolution of 1um, thereby solving the problem that the second probe of the sensor cannot be accurately and efficiently positioned to the zero gap by manually adjusting the second probe of the sensor in the traditional way in the past, and providing a method for adjusting the second probe of the sensor to the zero gap position with high precision and high efficiency, thereby providing a guarantee for the subsequent calibration curve and improving the calibration accuracy of the input and output characteristics of the differential eddy current displacement sensor.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: a differential eddy current displacement sensor calibration device, the device comprising a fixing device, a detection component, and an adjustment device, the adjustment device and the detection component are installed on the fixing device;

[0008] The detection assembly includes a detection assembly 1 and a detection assembly 2, the detection assembly 1 includes a bracket 1 and a first sensor probe, the detection assembly 2 includes a bracket 2 and a second sensor probe, and the first sensor probe and the second sensor probe are respectively installed on the corresponding two sides of the object to be detected;

[0009] The adjustment device includes a high-precision digital micrometer and a micrometer fine-tuning slide, wherein the rotating axis of the high-precision digital micrometer can be used to fix the object to be measured, and the horizontal displacement of the object to be measured can be adjusted by adjusting the handle of the high-precision digital micrometer. The detection component 2 is fixedly installed on the micrometer fine-tuning slide, and the position of the second probe of the sensor on the detection component 2 is adjusted by adjusting the horizontal displacement of the micrometer fine-tuning slide.

[0010] Preferably, the fixing device comprises a fixing base which can be fixedly mounted on a marble platform, and a bracket 1 is mounted on the fixing base, wherein the bracket 1 is used to mount a first sensor probe, and the bracket 2 on the detection component 2 is used to mount a second sensor probe.

[0011] Preferably, the micrometer fine-tuning slide is fixedly mounted on a fixed base, and the detection component 2 is fixed to the micrometer fine-tuning slide by bolts. Adjusting the regulator of the micrometer fine-tuning slide can drive the second sensor probe fixed on the detection component 2 to move forward or backward.

[0012] Preferably, the first sensor probe and the second sensor probe are respectively arranged on both sides of the object to be measured, and the two are arranged in the same straight line or in parallel.

[0013] Preferably, the high-precision digital micrometer is provided with a digital display screen which can display the position information of the measured object in real time.

[0014] Preferably, the device also includes a sensor controller electrically connected to the first sensor probe and the second sensor probe, the sensor controller is connected to a high-precision six-and-a-half-digit digital multimeter via a communication cable, and the sensor controller and the high-precision six-and-a-half-digit digital multimeter are both fixedly mounted on a marble platform.

[0015] Preferably, the high-precision digital micrometer is fixedly installed on one side of the fixed base. Adjusting the handle of the high-precision digital micrometer can adjust the rotating axis of the high-precision digital micrometer, driving the object fixed on the rotating axis to approach or move away from the first sensor probe and the second sensor probe.

[0016] Preferably, a calibration method for a differential eddy current displacement sensor calibration device comprises the following steps:

[0017] S1. Build a differential eddy current displacement sensor calibration device;

[0018] S2. Fix the first probe of the sensor and adjust the handle of the high-precision digital micrometer to make the object to be measured contact with the first probe of the sensor;

[0019] S3. Reversely adjust the high-precision digital micrometer to move the object to be measured away from the first probe of the sensor to the zero gap;

[0020] S4. Adjust the micrometer fine-tuning slide to adjust the distance between the second probe of the sensor and the object to be measured until the voltage reading of the high-precision six-and-a-half-digit digital multimeter is within the allowable deviation range of zero voltage (for example, 0V±0.005mV) and reaches the zero position state;

[0021] S5. Adjust the high-precision digital micrometer to move the object to be measured to the lower or upper limit of the range, adjust the gain adjustment potentiometer in the sensor controller circuit to make the output voltage reach the minimum or maximum value (such as -10V or +10V), and determine the gain;

[0022] S6. Adjust the high-precision digital micrometer with the specified step length, and record the displacement value and the corresponding voltage reading until the lower and upper limits of the range are reached;

[0023] S7. Fit the displacement and voltage data and use the least square method or polynomial method to obtain the calibration result of the differential eddy current displacement sensor.

[0024] Specifically, in step S4, the object to be tested is any metal such as copper, silver, aluminum, chromium, etc.

[0025] (III) Beneficial effects

[0026] The differential eddy current displacement sensor calibration device and calibration method provided by the present invention have the beneficial effects of improving calibration accuracy and efficiency, enhancing reliability, wide application range and simplifying operation process, etc., and provide strong support for the practical application of differential eddy current displacement sensors, which are specifically described as follows:

[0027] Improve calibration accuracy: By using a micrometer fine-tuning slide, the present invention can accurately adjust the position of the second probe of the sensor with a step resolution of 1um. This high-precision adjustment method significantly improves the positioning accuracy of the zero gap of the second probe of the sensor, thereby ensuring the accuracy of the calibration curve. The use of a high-precision digital micrometer allows the displacement of the object to be measured to be accurate to 0.1um, further improving the displacement measurement accuracy during the calibration process.

[0028] Improve calibration efficiency: The traditional method of manually adjusting the second probe of the sensor is difficult to operate and takes a long time. The present invention greatly simplifies the adjustment process and improves the calibration efficiency through the precise adjustment of the micrometer fine-tuning slide. The real-time display function of the digital display screen allows the operator to intuitively understand the displacement of the object being measured, so as to find the zero gap position more quickly.

[0029] Enhanced reliability: The present invention forms a stable and reliable calibration system through the organic combination of the fixing device, the detection component and the adjustment device. This structural design reduces the error and uncertainty caused by manual operation and improves the reliability of calibration. The use of a high-precision six-and-a-half-digit digital multimeter ensures the accuracy of the voltage reading and further enhances the reliability of the calibration result.

[0030] Wide range of applications: The present invention is suitable for the calibration of any metal such as copper, silver, aluminum, chromium, etc., and has wide applicability. Differential eddy current displacement sensors are widely used in industrial production, aviation industry, nuclear industry and other fields. The calibration device and method of the present invention can meet the needs of these fields for high-precision calibration.

[0031] Simplified operation process: The calibration method of the present invention has clear steps and is easy to operate, so even non-professionals can quickly get started. The calibration curve is obtained by data fitting, which simplifies the subsequent data processing process and improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the appearance structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the appearance structure of the present invention for fixing the object to be tested;

[0034] Figure 3 This is a schematic diagram of the appearance structure of the second probe of the adjustment sensor of the present invention;

[0035] Figure 4 This is a schematic diagram of the appearance structure of the first probe of the sensor used for fixing the sensor according to the present invention;

[0036] Figure 5 It is a schematic diagram of the overall appearance structure of the present invention;

[0037] Figure 6 It is a position relationship diagram of the sensor of the present invention when the output is zero;

[0038] Figure 7 It is a flow chart of the steps of the calibration method of the present invention;

[0039] Figure 8 It is a schematic diagram of the automatic adjustment system device;

[0040] In the figure: 1. Micrometer fine adjustment slide; 11. Regulator; 2. Detection component 2; 21. Sensor second probe; 22. Bracket 2; 3. Detection component 1; 31. Sensor first probe; 32. Bracket 1; 4. High-precision digital micrometer; 41. Handle; 42. Digital display screen; 43 Rotating axis; 5. Measured object; 6. Fixed base; 7. Sensor controller; 8. High-precision six-and-a-half-digit digital multimeter; 9. Marble platform; 10. Motor; 12. Controller; 13. Interface. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] Embodiment 1:

[0043] See also Figure 1-7 The embodiment of the present invention provides a calibration device for a differential eddy current displacement sensor, including a fixing device, a detection component and an adjustment device. The fixing device includes a fixing base 6 that can be fixedly mounted on a marble platform 9, a bracket 32 ​​and a micrometer fine-tuning slide 1 are mounted on the fixing base 6, a through hole 1 is provided on the bracket 32, a first sensor probe 31 is mounted on the bracket 32 ​​through the through hole 1, a bracket 22 is mounted on the micrometer fine-tuning slide 1, a through hole 2 is provided on the bracket 22, a second sensor probe 21 is mounted on the bracket 22 through the through hole 2, both ends of the first sensor probe 31 protrude from the through hole 1, both ends of the second sensor probe 21 protrude from the through hole 2, the bracket 22 is fixedly mounted on the micrometer fine-tuning slide 1 by bolts, and the bracket 32 ​​is fixedly mounted on the fixing base 6 by bolts.

[0044] The detection component includes a detection component 1 3 and a detection component 2 2. The detection component 1 3 and the detection component 2 2 are both installed above the fixed base 6. The detection component 1 3 includes a bracket 1 32 and a first sensor probe 31. The detection component 2 2 includes a bracket 22 and a second sensor probe 21. The first sensor probe 31 and the second sensor probe 21 are respectively installed on the corresponding two sides of the object to be measured 5, and the two are arranged in the same straight line or in parallel.

[0045] The adjustment device includes a micrometer fine adjustment slide 1 and a high-precision digital micrometer 4, wherein the high-precision digital micrometer 4 is fixedly mounted on one side of a fixed base 6. Adjusting the handle 41 of the high-precision digital micrometer 4 can adjust the rotating shaft 43 of the high-precision digital micrometer 4, driving the object 5 fixed on the rotating shaft 43 to approach (at this time, the object 5 is away from the second sensor probe 21) the first sensor probe 31, thereby controlling the object 5 to reach a zero position gap close to the first sensor probe 31. The micrometer fine adjustment slide 1 is fixedly mounted on the fixed base 6, and the detection component 2 is fixed to the micrometer fine adjustment slide 1 by bolts. Adjusting the regulator 11 of the micrometer fine adjustment slide 1 can drive the second sensor probe 21 fixed on the detection component 2 to move forward or backward, thereby adjusting the second sensor probe 21 to reach the zero position gap. The high-precision digital micrometer 4 is provided with a digital display screen 42 which can display the position information of the measured object 5 in real time. The resolution of the digital display screen 42 is 0.1um. The measured object 5 can be moved forward or backward by rotating the handle 41 of the high-precision digital micrometer 4. The displacement value of the measured object 5 forward or backward can be clearly read on the digital display screen 4. When the high-precision digital micrometer 4 is adjusted, the horizontal displacement of the measured object 5 can be adjusted so that the measured object 5 can contact the first probe 31 of the sensor.

[0046] A differential eddy current displacement sensor calibration device also includes a sensor controller 7 electrically connected to a first sensor probe 31 and a second sensor probe 21. The sensor controller 7 is connected to a high-precision six-and-a-half-digit digital multimeter 8 via a communication cable. The sensor controller 7 and the high-precision six-and-a-half-digit digital multimeter 8 are both fixedly mounted on a marble platform 9.

[0047] Specifically, a calibration method for a differential eddy current displacement sensor calibration device comprises the following steps:

[0048] S1. Building the differential eddy current displacement sensor calibration device;

[0049] S2, fix the first sensor probe 31, and adjust the high-precision digital micrometer 4 to make the measured object 5 contact with the first sensor probe 31;

[0050] S3, adjust the high-precision digital micrometer 4 in the reverse direction to keep the measured object 5 away from the first sensor probe 31, observe the reading on the digital display screen 4, and stop when the zero gap is reached. At this time, the measured object 5 reaches the zero gap position;

[0051] S4, adjust the micrometer fine adjustment slide 1 to make the second sensor probe 21 away from or close to the object 5, and observe the reading of the high-precision six-and-a-half-digit digital multimeter 8 until the deviation between the voltage value of the high-precision six-and-a-half-digit digital multimeter 8 and the zero voltage is within the allowable range (for example, 0V±0.005mV), at which time the calibration device is in the zero position state;

[0052] S5, adjust the high-precision digital micrometer 4 to drive the measured object 5 to move to the lower limit or upper limit of the range, and then adjust the gain adjustment potentiometer in the sensor controller 7 circuit to make the output voltage value of the sensor controller 7 circuit minimum or maximum (such as -10V or +10V), thereby determining the gain of the sensor controller 7 circuit under the specified zero gap and range;

[0053] S6, adjusting the high-precision digital display micrometer 4 from the current position with a specified step length, and synchronously recording the displacement value of the digital display screen 42 and the voltage reading of the high-precision six-and-a-half-digit digital multimeter 8 until the measured object 5 reaches the lower limit and the upper limit of the range;

[0054] S7. Perform data fitting on the obtained displacement values ​​and voltage values, and use the least square method or polynomial to obtain the calibration result of the differential eddy current displacement sensor.

[0055] Specifically, in step S4, the object to be tested is any metal such as copper, silver, aluminum, chromium, etc.

[0056] Embodiment 2:

[0057] This embodiment also provides a differential eddy current displacement sensor calibration device, and its basic structure is similar to that of Embodiment 1. On the basis of Embodiment 1, innovations and improvements are made, mainly to improve the automatic operation of the calibration device. Compared with Embodiment 1, the technical solution has the following improvements:

[0058] Adding an automatic adjustment system: A micro motor 10 currently available on the market is integrated on the micrometer fine adjustment slide 1. Figure 8 As shown, the motor 10 is connected to the controller 12, and more specifically can be integrated with the sensor controller 7 or independently set. The interface 13 is connected to the regulator 11 in a card socket manner, which can realize automatic fine-tuning of the position of the second probe 21 of the sensor; through the software interface of the controller, the user can input the target gap value, and the controller will automatically calculate and drive the micro-motor to adjust the micrometer fine-tuning slide 1, so that the second probe 21 of the sensor can accurately reach the specified position.

[0059] Dynamic feedback adjustment is achieved: the reading of the high-precision six-and-a-half-digit digital multimeter 8 is fed back to the controller in real time. When the position of the second sensor probe 21 is adjusted, the controller dynamically adjusts the stepping of the micromotor according to the voltage reading to achieve faster and more accurate zero gap positioning.

[0060] Intelligent calibration algorithm: The sensor controller 7 has a built-in intelligent calibration algorithm that can automatically analyze displacement and voltage data and use more advanced data fitting methods, such as the current mainstream neural network fitting, to improve the accuracy of the calibration results.

[0061] The specific working principle is as follows: first, the device is built, which is the same as Example 1, but a micro motor, a multi-axis platform and a controller are additionally installed. Then, the first probe 31 of the sensor is fixed and initially adjusted, that is, the first probe 31 of the sensor is fixed, and the object 5 to be measured is adjusted to contact with the first probe 31 of the sensor using a high-precision digital micrometer 4, and then reversely adjusted to the zero gap. After that, the second probe of the sensor is automatically adjusted, and the target zero gap value is input through the software interface. The controller drives the micro motor to automatically adjust the micrometer fine-tuning slide 1, and monitors the voltage reading of the high-precision six-and-a-half-digit digital multimeter 8 at the same time. When the voltage reading enters the allowable range (such as 0V±0.005mV), the controller stops the motor, and the second probe 21 of the sensor reaches the zero gap.

[0062] Finally, gain adjustment and data acquisition are performed, as in Example 1, the object under test 5 is adjusted to the lower or upper limit of the range, the gain adjustment potentiometer is adjusted, and then the displacement and voltage data are collected at a specified step size; the collected data is fitted using an intelligent calibration algorithm to obtain a more accurate calibration result.

[0063] This embodiment significantly improves the efficiency and accuracy of zero gap adjustment of the second probe of the sensor by integrating an automatic adjustment system and dynamic feedback adjustment; the application of the intelligent calibration algorithm improves the accuracy of the calibration results, providing strong support for the precise application of the differential eddy current displacement sensor.

[0064] Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents; in the present invention, unless otherwise clearly defined and defined, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it may be a fixed connection, or a detachable connection, or integrated; it may be a mechanical connection, or an electrical connection, or they may communicate with each other; it may be a direct connection, or it may be an indirect connection through an intermediate medium, it may be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0065] Obviously, the embodiments described above are only some embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are given in the accompanying drawings, but they do not limit the patent scope of the present invention. The present invention can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to replace some of the technical features therein with equivalents. Any equivalent structure made using the contents of the specification and drawings of the present invention, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present invention.

Claims

1. A differential eddy current displacement sensor calibration device, characterized in that: The device comprises a fixing device, a detection assembly, and an adjustment device, wherein the adjustment device and the detection assembly are mounted on the fixing device; The detection assembly includes a detection assembly 1 and a detection assembly 2, the detection assembly 1 includes a bracket 1 and a first sensor probe, the detection assembly 2 includes a bracket 2 and a second sensor probe, and the first sensor probe and the second sensor probe are respectively installed on the corresponding two sides of the object to be detected; The adjustment device includes a high-precision digital micrometer and a micrometer fine-tuning slide, wherein the rotating axis of the high-precision digital micrometer can be used to fix the object to be measured, and the horizontal displacement of the object to be measured can be adjusted by adjusting the handle of the high-precision digital micrometer. A detection component 2 is fixedly installed on the micrometer fine-tuning slide, and the position of the detection component 2 is adjusted by adjusting the horizontal displacement of the micrometer fine-tuning slide.

2. A differential eddy current displacement sensor calibration device according to claim 1, characterized in that: The fixing device comprises a fixing base which can be fixedly mounted on a marble platform, on which a bracket 1 and a detection component 2 are mounted, wherein the bracket 1 is used to mount a first sensor probe, and the bracket 2 on the detection component 2 is used to mount a second sensor probe.

3. The differential eddy current displacement sensor calibration device according to claim 1, characterized in that: The micrometer fine adjustment slide is fixedly installed on the fixed base, and the detection component 2 is fixed on the micrometer fine adjustment slide by bolts. Adjusting the regulator of the micrometer fine adjustment slide can drive the second sensor probe fixed on the detection component 2 to move forward or backward.

4. A differential eddy current displacement sensor calibration device according to claim 1 or 2, characterized in that: The first sensor probe and the second sensor probe are respectively arranged on two sides of the object to be measured, and the two are arranged in the same straight line or in parallel.

5. The differential eddy current displacement sensor calibration device according to claim 1, characterized in that: The high-precision digital micrometer is provided with a digital display screen which can display the position information of the measured object in real time.

6. The differential eddy current displacement sensor calibration device according to claim 1, characterized in that: The device also includes a sensor controller electrically connected to the first sensor probe and the second sensor probe, the sensor controller is connected to the high-precision six-and-a-half-digit digital multimeter through a communication cable, and the sensor controller and the high-precision six-and-a-half-digit digital multimeter are both fixedly installed on a marble platform.

7. The differential eddy current displacement sensor calibration device according to claim 5, characterized in that: The high-precision digital micrometer is fixedly installed on one side of the fixed base. Adjusting the handle of the high-precision digital micrometer can adjust the rotating axis of the high-precision digital micrometer, driving the object fixed on the rotating axis to move between the first probe and the second probe of the sensor.

8. A calibration method for a differential eddy current displacement sensor calibration device, characterized in that: The following steps are involved: S1. Build a differential eddy current displacement sensor calibration device; S2. Fix the first probe of the sensor and adjust the handle of the high-precision digital micrometer to make the object to be measured contact with the first probe of the sensor; S3. Reversely adjust the high-precision digital micrometer to move the object to be measured away from the first probe of the sensor to the zero gap; S4. Adjust the micrometer fine-tuning slide to adjust the distance between the second probe of the sensor and the object to be measured until the voltage reading of the high-precision six-and-a-half-digit digital multimeter is within the allowable deviation range of zero voltage and reaches the zero position state; S5. Adjust the high-precision digital micrometer to move the object to be measured to the lower or upper limit of the range, adjust the gain adjustment potentiometer in the sensor controller circuit to make the output voltage reach the minimum or maximum value, and determine the gain; S6. Adjust the high-precision digital micrometer with the specified step length, and record the displacement value and the corresponding voltage reading until the lower and upper limits of the range are reached; S7. Fit the displacement and voltage data and use the least square method or polynomial method to obtain the calibration result of the differential eddy current displacement sensor.

9. The calibration method of a differential eddy current displacement sensor calibration device according to claim 8, characterized in that: In step S4, the object to be measured is a metal, and the metal is one of copper, silver, aluminum, and chromium.

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