Calibration method for excitation voltage transfer coefficient based on capacitive sensing

Abstract

This invention relates to the field of electronic information technology, and more particularly to a calibration method for the excitation voltage transfer coefficient based on capacitive sensing. The method involves placing a test mass within an electrode cage, ensuring the test mass is centered within the cage; controlling the capacitive sensing circuit to input a first excitation voltage to the electrode cage and sensing the first sensing voltage output by the electrode cage; controlling the capacitive sensing circuit to input a second excitation voltage to the test mass, making the second sensing voltage output by the electrode cage equal to the first sensing voltage, at which point the first excitation voltage and the sensing voltage of the test mass are equal; and obtaining the voltage transfer coefficient from the electrode cage to the test mass based on the second and first excitation voltages. The method provided by this invention employs the zero-position method, measuring the voltage output of the capacitive sensing twice after fixing the test mass, thus avoiding additional impedance and distributed capacitance, and effectively reducing errors introduced by the measuring instrument.

Description

Technical Field

[0001] This invention belongs to the field of electronic information technology, and in particular relates to a calibration method for the excitation voltage transfer coefficient based on capacitive sensing. Background Technology

[0002] In space gravitational wave detection, capacitive sensing is typically used. By measuring the displacement change of the test mass of an inertial sensor through minute changes in capacitance, a position reference is provided for the system.

[0003] The inertial sensor system consists of three parts: a test mass, an electrode cage, and a capacitive sensing electronics system. The test mass is suspended by a metal wire at the center of the electrode cage, without direct contact with the cage. The magnitude of the excitation voltage sensed by the excitation electrodes on the test mass is related to the distance between the test mass and the electrode cage. However, because the test mass is suspended by the metal wire, it undergoes irregular motion due to factors such as gravity and the stiffness of the wire, making it impossible to obtain an accurate distance between the test mass and the electrode cage. Therefore, the excitation voltage sensed by the excitation electrodes on the test mass is unknown.

[0004] The drawback of existing methods is that measuring the quality-induced voltage directly requires the use of third-party measuring instruments, such as oscilloscopes and multimeters. It's crucial to consider whether the accuracy of these instruments meets the measurement requirements, as their accuracy significantly impacts the results. More importantly, the use of probes or test leads introduces additional impedance and distributed capacitance during testing, leading to unacceptable errors. Furthermore, the use of measuring instruments increases the system's complexity. Summary of the Invention

[0005] In view of this, the present invention aims to provide a calibration method for the excitation voltage transfer coefficient based on capacitive sensing. Based on the zero-position method, it only requires comparing the output voltage values ​​of two capacitive sensors. This process does not change the relationship between the inspection quality and the physical configuration of the electrode cage, and does not generate additional impedance or distributed capacitance, effectively reducing errors introduced by the measuring instrument. Furthermore, the present invention is simple, easy to operate, and readily implemented.

[0006] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0007] A calibration method for the excitation voltage transfer coefficient based on capacitive sensing, comprising:

[0008] S1: Place the inspection mass in the electrode cage so that the inspection mass is located at the center of the electrode cage;

[0009] S2: Control the capacitive sensing circuit to input the first excitation voltage to the electrode cage and sense the first sensing voltage output by the electrode cage;

[0010] S3: Control the capacitive sensing circuit to input the second excitation voltage to the inspection quality, so that the second sensing voltage output by the electrode cage is equal to the first sensing voltage in step S3. At this time, the first excitation voltage is equal to the sensing voltage of the inspection quality.

[0011] S4: Based on the second excitation voltage obtained in step S3 and the first excitation voltage in step S2, obtain the voltage transfer coefficient from the electrode cage to the inspection quality.

[0012] Furthermore, in step S1, both the electrode cage and the inspection mass are hexahedral structures; the two faces of the electrode cage in the X direction each include two sensing electrodes; the two faces of the electrode cage in the Y direction each include two sensing electrodes and one excitation electrode, with the excitation electrode placed between the two sensing electrodes; the two faces of the electrode cage in the Z direction each include two sensing electrodes and two excitation electrodes, with the two excitation electrodes placed between the two sensing electrodes, and the two excitation electrodes located on a straight line.

[0013] Furthermore, the capacitive sensing circuit includes: an excitation generation circuit for outputting an excitation voltage; and a capacitive sensing readout circuit for reading the output sensing voltage.

[0014] Furthermore, in step S2, the control excitation generation circuit inputs a first excitation voltage to any excitation electrode in the electrode cage, and reads the first sensing voltage obtained by any sensing electrode in the electrode cage through the capacitive sensing readout circuit.

[0015] Furthermore, in step S3, the excitation generating circuit inputs a second excitation voltage to the inspection quality through a wire, and reads the second sensing voltage obtained by any sensing electrode in the electrode cage through the capacitive sensing readout circuit.

[0016] Furthermore, step S4 yields the voltage transfer coefficient using the following formula:

[0017] ;

[0018] Where c represents the voltage transfer coefficient, V inj V represents the first excitation voltage. inj ' indicates the second excitation voltage.

[0019] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0020] This invention presents a calibration method for the excitation voltage transfer coefficient based on capacitive sensing. Employing the zero-position method, it adjusts the magnitude of a comparison quantity to closely approximate the measured quantity, which then indicates the magnitude of the measured quantity. Using the same coefficient reading as a reference, when output values ​​are identical, the amplitude of the excitation signal is compared. The measurement accuracy is consistent with the accuracy of the system's capacitive sensing readout, eliminating the need to consider the accuracy issues of direct measurement using third-party instruments, thus simplifying the testing equipment. Furthermore, because this invention uses a relative measurement method, it avoids the introduction of other equipment, thus preventing distributed capacitance and impedance changes caused by the connection of measuring devices such as test leads and probes, and avoiding the introduction of third-party noise sources. This reduces errors during measurement, increases the reliability of test results, and improves the accuracy of the results. In addition, this invention is simple, easy to operate, and readily implemented. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 A schematic flowchart illustrating the calibration method for the excitation voltage transfer coefficient based on capacitive sensing as described in the embodiments of the present invention.

[0023] Figure 2 A schematic diagram of the implementation circuit for the calibration method of excitation voltage transfer coefficient based on capacitive sensing described in the embodiment of the present invention;

[0024] Figure 3 A three-dimensional structural schematic diagram of the electrode cage described in an embodiment of the present invention;

[0025] Figure 4 (a) A schematic diagram of the electrode cage in the X direction according to an embodiment of the present invention;

[0026] Figure 4 (b) A schematic diagram of the electrode cage in the Y direction according to an embodiment of the present invention;

[0027] Figure 4 (c) A schematic diagram of the electrode cage in the Z direction according to an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the capacitive sensing circuit described in an embodiment of the present invention.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Quality inspection; 2. Electrode cage; 3. Sensing electrode; 4. Excitation electrode; 5. Wire; 6. Capacitive sensing circuit. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] like Figure 1 and Figure 2 As shown in the embodiment of the present invention, the calibration method for the excitation voltage transfer coefficient based on capacitive sensing includes:

[0037] S1: Place the inspection mass 1 in the electrode cage 2, so that the inspection mass 1 is located at the center of the electrode cage 2.

[0038] In some embodiments, both the electrode cage 2 and the inspection mass 1 are hexahedral structures. The structure of the electrode cage 2 is as follows: Figure 3 and Figure 4 As shown, the two faces of the electrode cage 2 in the X direction each include two sensing electrodes 3; the two faces of the electrode cage 2 in the Y direction each include two sensing electrodes 3 and one excitation electrode 4, and the excitation electrode 4 is placed between the two sensing electrodes 3; the two faces of the electrode cage 2 in the Z direction each include two sensing electrodes 3 and two excitation electrodes 4, the two excitation electrodes 4 are placed between the two sensing electrodes 3, and the two excitation electrodes 4 are located on a straight line.

[0039] In this embodiment of the invention, a metal rod is used instead of a metal suspension wire to form a rigid, insulated connection with the inspection mass 1, keeping the inspection mass 1 at a fixed position at the center of the electrode cage 2. A wire 5 is led out from the inspection mass 1; to reduce impedance and increase conductivity, the wire 5 is preferably made of gold wire. Furthermore, in this embodiment, the electrode cage 2 is insulated and placed on a six-axis positioning stage. By adjusting the six-axis positioning stage, the relative position of the electrode cage 2 and the inspection mass 1 is changed, keeping the inspection mass 1 at a fixed position at the center of the electrode cage 2.

[0040] S2: Control the capacitive sensing circuit 6 to input the first excitation voltage to the electrode cage 2, and sense the first sensing voltage output by the electrode cage 2.

[0041] The principle of the capacitance sensing circuit 6 is to use the excitation signal as a carrier signal, and convert the coupled capacitance value into a voltage signal through a transformer. After signal conditioning through circuits such as amplification, filtering, and demodulation, the signal is output to the analog-to-digital converter for data acquisition. The capacitance value is measured by measuring the magnitude of the voltage signal.

[0042] In some embodiments, the capacitive sensing circuit 6 includes an excitation generating circuit and a capacitive sensing readout circuit. The excitation generating circuit outputs an excitation voltage, and the capacitive sensing readout circuit reads the output sensing voltage. Correspondingly, the excitation generating circuit is controlled to input a first excitation voltage to any excitation electrode 4 in the electrode cage 2, and the first sensing voltage obtained from any sensing electrode 3 in the electrode cage 2 is read through the capacitive sensing readout circuit.

[0043] In this embodiment of the invention, the capacitance sensing circuit 6 is as follows: Figure 5 As shown, the excitation generation circuit generates a stable 100kHz sinusoidal excitation signal as a carrier signal, which is applied to the excitation electrode of the capacitor under test. The capacitance sensing readout circuit includes a transformer, preamplifier, signal conditioning, demodulation, and analog-to-digital converter, which can convert the capacitance signal into a voltage signal to measure the capacitance value.

[0044] S3: Control the capacitive sensing circuit 6 to input the second excitation voltage to the inspection quality 1, so that the second sensing voltage output by the electrode cage 2 is equal to the first sensing voltage in step S3. At this time, the first excitation voltage is equal to the sensing voltage of the inspection quality 1.

[0045] In some embodiments, the excitation generating circuit inputs a second excitation voltage to the inspection quality 1 through the wire 5, and reads the second sensing voltage obtained by any sensing electrode 3 in the electrode cage 2 through the capacitive sensing readout circuit.

[0046] In this embodiment of the invention, the process specifically includes: the capacitive sensing circuit 6 injects the generated second excitation voltage into the excitation electrode 4, and then senses it onto the inspection mass 1 through the excitation electrode 4. The magnitude of the second excitation voltage is related to the configuration of the inspection mass 1 and the electrode cage 2. However, due to manufacturing errors, the influence of various factors such as the surface finish, parallelism, and coating process of the excitation electrode 4, the second excitation voltage induced from the excitation electrode 4 to the inspection mass 1 cannot be accurately calculated. It can only be obtained through actual measurement.

[0047] S4: Based on the second excitation voltage obtained in step S3 and the first excitation voltage in step S2, the voltage transfer coefficient from electrode cage 2 to inspection mass 1 is obtained.

[0048] In some embodiments, the voltage transfer coefficient is obtained by the following formula:

[0049] ;

[0050] Where c represents the voltage transfer coefficient, V inj V represents the first excitation voltage. inj ' indicates the second excitation voltage, V TM This represents the sensing voltage of the test quality 1.

[0051] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0052] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for calibrating the excitation voltage transfer coefficient based on capacitive sensing, characterized in that, include: S1: Place the inspection mass in the electrode cage so that the inspection mass is located at the center of the electrode cage; S2: Control the capacitive sensing circuit to input the first excitation voltage to the electrode cage and sense the first sensing voltage output by the electrode cage; S3: Control the capacitive sensing circuit to input the second excitation voltage to the inspection quality, so that the second sensing voltage output by the electrode cage is equal to the first sensing voltage in step S2. At this time, the first excitation voltage is equal to the sensing voltage of the inspection quality. S4: Based on the second excitation voltage obtained in step S3 and the first excitation voltage in step S2, obtain the voltage transfer coefficient from the electrode cage to the inspection quality.

2. The calibration method for the excitation voltage transfer coefficient based on capacitive sensing according to claim 1, characterized in that, In step S1, both the electrode cage and the inspection mass are hexahedral structures. The electrode cage has two sensing electrodes on each of its two faces in the X direction; two sensing electrodes and one excitation electrode on each of its two faces in the Y direction, with the excitation electrode placed between the two sensing electrodes; and two sensing electrodes and two excitation electrodes on each of its two faces in the Z direction, with the two excitation electrodes placed between the two sensing electrodes and the two excitation electrodes located on a straight line.

3. The calibration method for the excitation voltage transfer coefficient based on capacitive sensing according to claim 2, characterized in that, The capacitive sensing circuit includes: Excitation generating circuit, used to output excitation voltage; The capacitive sensing readout circuit is used to read the output sensed voltage.

4. The calibration method for the excitation voltage transfer coefficient based on capacitive sensing according to claim 3, characterized in that, In step S2, the control excitation generation circuit inputs a first excitation voltage to any excitation electrode in the electrode cage, and reads the first sensing voltage obtained by any sensing electrode in the electrode cage through the capacitive sensing readout circuit.

5. The calibration method for the excitation voltage transfer coefficient based on capacitive sensing according to claim 3, characterized in that, In step S3, the excitation generating circuit inputs a second excitation voltage to the inspection quality through a wire, and reads the second sensing voltage obtained by any sensing electrode in the electrode cage through the capacitive sensing readout circuit.

6. The calibration method for the excitation voltage transfer coefficient based on capacitive sensing according to claim 1, characterized in that, Step S4 yields the voltage transfer coefficient using the following formula: ； Where c represents the voltage transfer coefficient, V inj V represents the first excitation voltage. inj ' indicates the second excitation voltage.

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