A displacement detection device based on 3D electromagnetic induction of a coil

Abstract

This utility model relates to the field of displacement detection technology, specifically to a displacement detection device based on 3D coil electromagnetic induction, comprising: a 3D coil, including coils arranged along the X, Y, and Z axes, for sensing the displacement of a target object; an LC resonant circuit connected to the 3D coil for generating a resonant signal; an inductor-to-digital converter connected to the LC resonant circuit for detecting frequency changes of the resonant signal and converting the frequency changes into digital signals; and a microcontroller connected to the inductor-to-digital converter for receiving the digital signals and calculating the three-dimensional displacement of the target object based on the digital signals. This utility model, employing a 3D coil structure, can effectively improve the detection accuracy of three-dimensional displacement. This structure can also expand the displacement detection range, enabling its application in a wider range of scenarios.

Description

Technical Field

[0001] This utility model relates to the field of displacement detection technology, specifically to a displacement detection device based on 3D electromagnetic induction of a coil. Background Technology

[0002] Displacement detection is a key technology in industrial automation, robotics, and precision measurement. Inductive displacement sensors are widely used due to their simple structure, low cost, and high reliability. However, traditional inductive displacement sensors typically employ a planar coil structure, which has limitations when detecting three-dimensional displacement: planar coils are insensitive to displacements perpendicular to the coil plane, making it difficult to achieve high-precision three-dimensional displacement detection; furthermore, to ensure detection accuracy, the detection range of planar coils is usually small. To address these issues, researchers began to study inductive displacement sensors based on three-dimensional coil structures. However, existing three-dimensional coil structures still suffer from structural complexity, high manufacturing difficulty, and low accuracy. Therefore, there is an urgent need for a displacement detection device based on 3D electromagnetic induction of a three-dimensional coil that features a simple structure, high detection accuracy, and a wide detection range. Utility Model Content

[0003] The main objective of this invention is to overcome the aforementioned shortcomings of the existing technology and to provide a displacement detection device based on 3D electromagnetic induction of a coil, characterized by comprising: A 3D coil, comprising coils arranged along the X, Y, and Z axes, is used to sense the displacement of a target object; An LC resonant circuit, connected to the 3D coil, is used to generate a resonant signal; An inductor-to-digital converter, connected to the LC resonant circuit, is used to detect the frequency change of the resonant signal and convert the frequency change into a digital signal; A microcontroller, connected to the inductive digital converter, is used to receive the digital signal and calculate the three-dimensional displacement of the target object based on the digital signal.

[0004] Furthermore, the 3D stereo coil is an orthogonal triaxial coil, which includes three mutually orthogonal planar spiral coils.

[0005] Furthermore, the planar spiral coil has a line width of 0.2 mm, a spacing of 0.3 mm, an outer diameter of 10 mm, and an inductance of 10 μH ± 5%.

[0006] Furthermore, the 3D coil is a spherical wound coil, which is formed by winding enameled wire around a non-metallic frame.

[0007] Furthermore, the enameled wire has a diameter of 0.1 mm and is wound 50 times, and the spherical winding coil has an outer diameter of 15 mm.

[0008] Furthermore, the LC resonant circuit includes a capacitor connected in parallel with the 3D coil, the capacitor having a capacitance of 100pF and being made of NPO material.

[0009] Furthermore, the sampling frequency of the inductor-to-digital converter is 1MHz, and the resolution is 16 bits.

[0010] Furthermore, it also includes a power management module for providing power to the 3D coil, LC resonant circuit, inductor-to-digital converter, and microcontroller. Beneficial effects

[0011] This invention employs a 3D coil structure, which effectively improves the detection accuracy of three-dimensional displacement. This structure also expands the displacement detection range, enabling its application in a wider range of scenarios. The device's structure is simple and easy to manufacture, thus reducing production costs. By integrating an LDC chip and a microcontroller (MCU), the device's integration and intelligence level are significantly improved, making it more advantageous in practical applications. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a displacement detection device based on orthogonal triaxial coils.

[0013] Figure 2 This is a schematic diagram of an orthogonal triaxial coil. Figure 3 This describes the signal processing flow of the displacement detection device.

[0014] Figure 4 This is a flowchart of the displacement calculation algorithm built into the MUC.

[0015] Figure 5 This is a schematic diagram of a spherical wound coil. Detailed Implementation

[0016] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0017] like Figure 1As shown, this embodiment provides a displacement detection device based on an orthogonal triaxial coil, including: a 3D coil, an LC resonant circuit, an inductor-to-digital converter (LDC), a microcontroller (MCU), and a power management module.

[0018] In this embodiment, the 3D stereo coil 1 adopts an orthogonal triaxial coil structure, such as... Figure 2 As shown, three mutually orthogonal planar spiral coils 11, 12, and 13 are arranged along the X, Y, and Z axes, respectively, to sense the three-dimensional displacement of the target object 6. To ensure the accuracy and consistency of the coils, the planar spiral coils are fabricated using a four-layer PCB process. The top and bottom layers form the main body of the coil, while the two middle layers can be used to shield interference signals or as auxiliary traces. The line width is 0.2 mm, the spacing is 0.3 mm, the outer diameter is 10 mm, and the inductance is 10 μH ± 5%. In practical applications, the size and number of turns of the coils can be adjusted according to different detection ranges and accuracy requirements. The substrate material of the coils is preferably FR4 to ensure good mechanical strength and electrical performance.

[0019] The LC resonant circuit includes a capacitor connected in parallel with the 3D coil 1 to generate the resonant signal. The capacitor has a capacitance of 100pF and is made of NP0 material. NP0 capacitors have the advantages of low temperature coefficient and high stability, ensuring the stability of the resonant frequency. To improve the Q value of the resonant circuit, a high-Q capacitor and low-loss PCB material can be selected. Furthermore, a fine-tuning capacitor can be used to precisely adjust the resonant frequency to meet the needs of different applications.

[0020] The inductor-to-digital converter (LDC) uses the TI LDC1614 chip to detect changes in the resonant frequency of an LC resonant circuit and convert these frequency changes into digital signals. The LDC1614 has a sampling frequency of 1MHz and a 16-bit resolution. It integrates multiple channels, allowing simultaneous detection of frequency changes in multiple coils, thus achieving higher precision displacement detection. The LDC1614 also features temperature compensation to eliminate the impact of temperature variations on the detection results.

[0021] The microcontroller (MCU) uses an STM32F103 series chip, connected to an LDC (Local Diode Controller), to receive digital signals output from the LDC and calculate the three-dimensional displacement of the target object based on these signals. The MCU integrates a displacement calculation algorithm, capable of calculating the X, Y, and Z axis coordinates of the target object in real time. The displacement calculation algorithm can employ methods such as lookup tables, polynomial fitting, or neural networks. To improve calculation accuracy, the displacement calculation model can be calibrated, and algorithms such as Kalman filtering can be used to filter the measurement results.

[0022] The power management module uses an LDO regulator chip, such as the AMS1117, to provide a stable 3.3V power supply for the entire device. The power management module also includes overvoltage protection, overcurrent protection, and short-circuit protection to improve the device's reliability. Alternatively, battery power can be used for portable applications. like Figure 3 As shown, when a target object approaches the 3D coil, it causes a change in the inductance of the coil, resulting in a change in the resonant frequency of the LC resonant circuit. The LD detects this change in resonant frequency, converts it into a digital signal, and sends it to the MCU. The MCU calculates the three-dimensional displacement of the target object based on the received digital signal and a pre-calibrated displacement calculation model. A specific implementation of this device is given below: Perform the following calibration steps when using the system for the first time: Record the reference resonant frequency f of each coil in an environment without metal objects. ox ,f oy ,f oz ; Move a standard metal block (aluminum, 5mm×5mm×5mm) 1mm along the X / Y / Z axes respectively, and record the frequency offset Δf. x , △f y , △f z Establish the displacement-frequency relationship matrix:

[0023] Where K is a 3×3 calibration matrix fitted by the least squares method.

[0024] microcontrollers are based on, for example Figure 4 The process shown executes the following steps in real time: (1) Read the three-axis frequency value f output by the LDC chip x， f y， f z (2) Calculate the frequency offset Δf = f0 − f; (3) Calculate the displacement based on the calibration matrix and compensate for the thermal drift of the coil resistance using a temperature sensor. (4) Output three-dimensional displacement data (unit: mm) and upload it to the host computer via UART.

[0025] The measurement errors of this device compared to a traditional planar LDC were compared using a high-precision displacement platform (resolution 0.001 mm) at 25℃, as shown in the table below: X-axis ±0.003 ±0.015 Y-axis ±0.004 ±0.018 Z-axis ±0.005 Unable to detect To verify the anti-interference capability of the device in this embodiment, a switching power supply (noise 20mVpp) was placed 10cm away from the coil group. The output fluctuation of this device was <0.002mm, while the fluctuation of a traditional Hall sensor was >0.1mm. This demonstrates its strong anti-interference performance. Example

[0026] like Figure 5 As shown, this embodiment provides a displacement detection device based on a spherical wound coil, the main difference from embodiment 1 being the structure of the 3D coil.

[0027] In this embodiment, the 3D coil adopts a spherical wound coil structure, formed by winding 0.1mm diameter enameled wire around a non-metallic frame. The enameled wire is wound 50 times, and the outer diameter of the spherical wound coil is 15mm. The non-metallic frame can be made of materials such as plastic, ceramic, or glass. To improve the mechanical strength of the coil, an epoxy resin coating can be applied to the coil surface. Other components are the same as in Embodiment 1, and the working principle is similar.

[0028] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A displacement detection device based on 3D electromagnetic induction of a coil, characterized in that, include: A 3D coil, comprising coils arranged along the X, Y, and Z axes, is used to sense the displacement of a target object; An LC resonant circuit, connected to the 3D coil, is used to generate a resonant signal; An inductor-to-digital converter, connected to the LC resonant circuit, is used to detect the frequency change of the resonant signal and convert the frequency change into a digital signal; A microcontroller, connected to the inductive digital converter, is used to receive the digital signal and calculate the three-dimensional displacement of the target object based on the digital signal.

2. The displacement detection device based on 3D stereoscopic coil electromagnetic induction according to claim 1, characterized in that: The 3D coil is an orthogonal triaxial coil, which includes three mutually orthogonal planar spiral coils.

3. The displacement detection device according to claim 2, characterized in that: The planar helical coil has a line width of 0.2 mm, a spacing of 0.3 mm, an outer diameter of 10 mm, and an inductance of 10 μH ± 5%.

4. The displacement detection device according to claim 1, characterized in that: The 3D coil is a spherical wound coil, which is formed by winding enameled wire around a non-metallic frame.

5. The displacement detection device according to claim 4, characterized in that: The enameled wire has a diameter of 0.1 mm and is wound 50 times. The outer diameter of the spherical winding coil is 15 mm.

6. The displacement detection device according to claim 1, characterized in that: The LC resonant circuit includes a capacitor connected in parallel with the 3D coil. The capacitor has a capacitance of 100pF and is made of NPO material.

7. The displacement detection device according to claim 1, characterized in that: The inductor-to-digital converter has a sampling frequency of 1MHz and a resolution of 16 bits.

8. The displacement detection device according to claim 1, characterized in that: It also includes a power management module for providing power to the 3D coil, LC resonant circuit, inductor-to-digital converter, and microcontroller.

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