Phase synchronization monitoring and adjusting method for multichannel excitation signals

Abstract

The invention belongs to the technical field of space inertial sensors, and particularly relates to a phase synchronization monitoring and adjusting method for multichannel excitation signals. Comprising the steps that S1, a test platform is built, and the test platform comprises a sensitive probe and capacitance sensing electronics; s2, enabling the center of the electrode cage to have small displacement relative to the center of the detection polar plate in the X-axis direction of the detection polar plate, and transmitting different excitation signals to each excitation polar plate by capacitive sensing electronics; s3, iteratively adjusting the initial phase of each excitation signal based on an optimization algorithm; and S4, when the measured induced voltage output by the to-be-measured induction pole plate pair after the initial phase is adjusted for two adjacent times meets an iteration stop condition, completing the phase synchronous monitoring and adjustment of the multichannel excitation signal. According to the invention, the influence of the structural design of the sensitive probe of the capacitive displacement sensor, line delay and other factors on multichannel excitation signal phase delay can be offset, and the sensitivity is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of space inertial sensors, and in particular relates to a phase synchronization monitoring and adjustment method for multi-channel excitation signals. Background Art

[0002] Differential capacitance displacement sensors are widely used in aerospace and other fields, especially in weak force measurement, such as inertial sensors, electrostatic accelerometers and electrostatic torsion balances. Differential capacitance displacement sensors are non-contact sensors. The basic principle is to use detection plates and induction plates to form multi-channel differential capacitance, apply AC excitation signals to the detection plates, read the induction plate voltage through bridge circuits and demodulation circuits, and thus convert capacitance signals into voltage signals.

[0003] Due to special design requirements or installation conditions, the excitation signal of the differential capacitive displacement sensor cannot be directly applied to the detection plate. The excitation signal needs to be applied indirectly through the excitation electrode. At the same time, considering the system symmetry and excitation injection efficiency, multiple excitation signals are required.

[0004] However, the phase delay caused by factors such as line delay, electronics and structural design differences makes the phases of the excitation signals misaligned, resulting in the amplitude of the composite signal acting on the detection plate unable to reach the designed maximum value, causing the capacitive sensing scale factor to be less than the theoretical value, thereby reducing the sensitivity of the capacitive sensor.

[0005] In the field of space inertial sensor research, Zhu Sheng of Huazhong University of Science and Technology published a doctoral dissertation in 2023, "Research on Capacitance Extraction and Injection Optimization of Sensitive Probes for High-Precision Capacitive Displacement Sensors", which proposed an online measurement and correction scheme for the amplitude and phase of four-way injection excitation signals based on FFT, and conducted simulations and related experiments. This study only focuses on a single electronic machine, without connecting sensitive probes, and does not consider the influence of line delay and sensitive probe structure on the phase of the excitation signal acting on the detection electrode. Other studies have not considered this issue and directly calculated the scale factor of capacitive sensing theoretically.

[0006] The Chinese invention patent named "Multi-channel capacitive displacement sensing circuit amplitude-phase-frequency characteristic measurement and de-embedding method" (publication number CN117368583A, publication date January 9, 2024) can remove the influence of the calibration auxiliary test unit on the measurement results. The results obtained by this method can improve the actual transmission characteristics of each displacement sensing channel and improve the overall performance of the circuit. The problem considered is to solve the problem of testing the frequency characteristics of the capacitive sensing signal between the multi-channel sensing plates, not the phase difference of the multi-channel excitation signal. Summary of the invention

[0007] In view of this, the invention aims to provide a phase synchronization monitoring and adjustment method for a multi-channel excitation signal, so as to solve the problem that the phase delay caused by factors such as line delay, electronics and structural design differences in the prior art makes the phases of the excitation signals of each channel misaligned, resulting in the synthetic signal amplitude acting on the detection plate failing to reach the designed maximum value, and the capacitive sensing scale factor being less than the theoretical value, thereby reducing the sensitivity of the capacitive sensing. The present invention adjusts the initial phase of the multi-channel excitation signal through an optimization algorithm, offsets the influence of factors such as the sensitive probe structure design and line delay of the capacitive displacement sensor on the phase delay of the multi-channel excitation signal, thereby increasing the scale factor of the capacitive displacement sensor and improving the sensitivity.

[0008] To achieve the above object, the technical solution created by the present invention is implemented as follows: A method for synchronously monitoring and adjusting the phase of a multi-channel excitation signal is used to realize synchronously monitoring and adjusting the phase of a multi-channel excitation signal of a capacitive displacement sensor, and specifically comprises the following steps: S1: Build the test platform, which includes sensitive probes and capacitive sensing electronics; The sensitive probe includes an electrode cage, a six-legged adjustment platform, a plurality of excitation plates and a plurality of induction plates fixed on the electrode cage in an insulated manner, and a detection plate located in the electrode cage. The six-legged adjustment platform drives the electrode cage to move with six degrees of freedom relative to the detection plate. S2: In a vacuum environment, the electrode cage is moved along the X-axis direction of the detection electrode plate, so that the center of the electrode cage has a small displacement in the X-axis direction of the detection electrode plate relative to the center of the detection electrode plate. The capacitive sensing electronics transmits different excitation signals to each excitation electrode plate, so that the detection electrode plate and each induction electrode plate pair generate an induced voltage. The relationship between the induced voltage output by each induction electrode plate pair and the amplitude of the induced voltage output by the detection electrode plate is: ; ; in, is the induced voltage output by each pair of inductive plates, is the gain of the capacitive sensing circuit of the capacitive sensing electronics, To detect the amplitude of the induced voltage output by the plate, is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the voltage divider ratio from the i-th excitation plate to the detection plate, is the amplitude of the i-th excitation signal, is the initial phase of the i-th excitation signal, n=6; S3: randomly select a sensing plate pair in the X-axis direction of the detection plate as the sensing plate pair to be tested, and iteratively adjust the initial phase of each excitation signal based on the optimization algorithm so that the initial phases of two adjacent adjustments satisfy the following formula: ; in, For the When adjusting for the first time, the initial phase of the i-th excitation signal is For the When adjusting for the first time, the initial phase of the i-th excitation signal is is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the learning rate, is the induced voltage output by the inductive plate pair to be tested; S4: Use capacitive sensing electronics to measure the induced voltage output by the inductive plate pair to be tested in real time. When the induced voltage output by the inductive plate pair to be tested measured after two consecutive initial phase adjustments satisfies the following formula, the iteration is stopped to complete the phase synchronization monitoring and adjustment of the multi-channel excitation signal: ; in, For the During the first adjustment, the induction voltage of the induction plate to be tested is For the During the first adjustment, the induction voltage of the induction plate to be tested is Stop parameter for the iteration.

[0009] Further, in step S1, the capacitive sensing electronics includes a capacitive sensing circuit and a data processing device connected in sequence, the capacitive sensing circuit is used to transmit an excitation signal to each excitation plate and measure the induced voltage output by the induction plate pair to be tested, and the data processing device is used to run the optimization algorithm; The sensitive probe also includes a fixing device and a vacuum tank, wherein the fixing device, the electrode cage, the six-legged adjustment platform, a plurality of excitation plates, a plurality of induction plates, the electrode cage and the detection plates are all placed in the vacuum tank; The fixing device suspends the detection electrode plate in the electrode cage, and a plurality of induction electrodes are evenly distributed on the electrode cage in an insulated form around the detection electrode plate, and a plurality of excitation electrodes are symmetrically arranged on the electrode cage in an insulated form along the Y-axis direction and the Z-axis direction of the detection electrode plate.

[0010] Furthermore, the detection electrode plate is a cube, the electrode cage is a cube with a hollow interior, and the capacitive sensing circuit is connected to the sensing electrode plate to be detected and the excitation electrode plate through cables.

[0011] Further, in step S2, different excitation signals have the same frequency but different initial phases.

[0012] Furthermore, in step S2, the induced voltage output by the plate is detected. The expression is: ; in, is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the voltage divider ratio from the i-th excitation plate to the detection plate, is the amplitude of the i-th excitation signal, is the initial phase of the i-th excitation signal, is the angular frequency of the excitation signal, n=6.

[0013] Furthermore, in step S2, the smaller displacement is any value between 10 micrometers and 20 micrometers.

[0014] Furthermore, in step S3, the optimization algorithm is a gradient ascent algorithm, Newton's method or a neural network method.

[0015] Furthermore, in step S3: .

[0016] Further, in step S4, the output voltage of the induction plate pair to be tested is : ; in, represents the gain of the capacitive sensing circuit, represents the input of the differential capacitance of the sensing plate pair, K is the scale factor, is the amplitude of the i-th excitation signal, It is the voltage divider ratio from the i-th excitation plate to the detection plate.

[0017] Compared with the prior art, the invention can achieve the following beneficial effects: (1) The phase synchronization monitoring and adjustment method of the multi-channel excitation signal created by the present invention takes into account the influence of factors such as sensitive probe structure design and line delay on the phase delay of the multi-channel excitation signal. Compared with existing research, it is closer to practical application and fills the gap in the research field.

[0018] (2) The phase synchronization monitoring and adjustment method of the multi-channel excitation signal created by the present invention does not directly measure the phase delay, but changes the initial phase of the excitation signal by fixing the detection electrode, and finds the maximum value of the capacitive sensor output signal to offset the influence of the line delay, thereby achieving the purpose of synchronizing the phase of the excitation signal, and finally improving the sensitivity of the capacitive sensor measurement. The present invention is simple and efficient, and does not require the addition of additional monitoring equipment.

[0019] (3) The phase synchronization monitoring and adjustment method of the multi-channel excitation signal created by the present invention takes into account the characteristic that the excitation plate is not distributed in the x-axis direction in the structural design of the sensitive probe, and selects the x-axis capacitive sensing output voltage signal as the target signal, thereby reducing the influence of the excitation plate on the sensing plate and improving the accuracy of the test. At the same time, the slight position offset in the x-axis direction has little effect on the capacitance distribution of the excitation plate in the sensitive probe, so that the voltage divider ratio from the voltage applied on the excitation plate to the detection plate remains basically unchanged, thereby increasing the applicability and accuracy of the test method. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 A schematic diagram of the structure of a capacitive displacement sensor according to an embodiment of the present invention; Figure 2 A schematic diagram of the distribution of electrode plates of the sensitive probe according to an embodiment of the present invention; Figure 3 A flow chart of a method for synchronously monitoring and adjusting phases of multi-channel excitation signals according to an embodiment of the present invention; Figure 4 A phase convergence diagram of each excitation signal described in the embodiment of the present invention; Figure 5 The invention creates a convergence diagram of the output voltage of the induction plate to be tested according to the embodiment of the invention.

[0021] Description of reference numerals: 1. Electrode cage; 2. Induction plate; 3. Detection plate; 4. Six-legged adjustment platform; 5. Excitation plate; 6. Fixing device; 7. Vacuum tank; 8. Capacitive sensing circuit; 9. Data processing equipment. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0025] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0027] like Figure 1 As shown, the test platform (i.e., the capacitive displacement sensor) includes a sensitive probe and capacitive sensing electronics; the sensitive probe includes an electrode cage 1, a six-legged adjustment platform 4, a plurality of excitation plates 5 and a plurality of induction plates 2 fixed on the electrode cage 1 in an insulated manner, a detection plate 3 located in the electrode cage 1, a fixture 6, and a vacuum tank 7; the fixture 6, the electrode cage 1, the six-legged adjustment platform 4, a plurality of excitation plates 5 (the number mentioned here is greater than 2), a plurality of induction plates 2, the electrode cage 1, and the detection plate 3 are all placed in the vacuum tank 7; the fixture 6 suspends the detection plate 3 in the electrode cage 1, a plurality of induction plates 2 are evenly distributed on the electrode cage 1 in an insulated manner around the detection plate 3, a plurality of excitation plates 5 are symmetrically arranged on the electrode cage 1 in an insulated manner along the Y-axis direction and the Z-axis direction of the detection plate 3, and the six-legged adjustment platform 4 drives the electrode cage 1 to move with six degrees of freedom relative to the detection plate 3. The X-axis direction, the Y-axis direction, and the Z-axis direction of the detection plate 3 satisfy the right-hand rule.

[0028] The capacitive sensing electronics includes a capacitive sensing circuit 8 and a data processing device 9 connected in sequence. The capacitive sensing circuit 8 is used to transmit an excitation signal to each excitation plate 5 and measure the induced voltage output by the inductive plate pair to be tested. The data processing device 9 is used to run the optimization algorithm.

[0029] In some embodiments, the detection electrode plate 3 is a cube, the electrode cage 1 is a hollow cube, and the capacitive sensing circuit 8 is connected to the sensing electrode plate to be detected and the excitation electrode plate 5 through cables.

[0030] Figure 2 The figure shows the relative position relationship of the detection plate 3, the induction plate 2, and the excitation plate 5 in the sensitive probe. The detection plate 3 is a cube and is located in the center of the sensitive probe. The induction plates 2 are symmetrically distributed around the detection plate 3. The induction plates are distributed at equal intervals along the positive and negative directions of the X-axis. , the sensing plates are distributed with equal spacing along the positive and negative directions of the Y axis , the sensing plates are distributed at equal intervals along the positive and negative directions of the Z axis The excitation electrodes J are symmetrically distributed relative to the detection electrode 3, and the excitation electrodes are distributed in equal intervals along the positive and negative directions of the Y axis. ; The excitation plates are distributed at equal intervals along the positive and negative directions of the Z axis .

[0031] like Figure 3 As shown, the phase synchronization monitoring and adjustment method of the multi-channel excitation signal of the present invention is used to realize the phase synchronization monitoring and adjustment of the multi-channel excitation signal of the capacitive displacement sensor, and specifically comprises the following steps: S1: building a test platform, the test platform comprising a sensitive probe and capacitive sensing electronics; The sensitive probe comprises an electrode cage 1, a six-legged adjustment platform 4, a plurality of excitation plates 5 and a plurality of induction plates 2 fixed on the electrode cage 1 in an insulated manner, and a detection plate 3 located in the electrode cage 1. The six-legged adjustment platform 4 drives the electrode cage 1 to move with six degrees of freedom relative to the detection plate 3. S2: In a vacuum environment, the electrode cage 1 is moved along the X-axis direction of the detection electrode plate 3, so that the center of the electrode cage 1 has a small displacement relative to the center of the detection electrode plate 3 in the X-axis direction of the detection electrode plate 3. The capacitive sensing electronics transmits different excitation signals to each excitation electrode plate 5, so that the detection electrode plate 3 and each induction electrode pair generate an induced voltage. The relationship between the amplitude of the induced voltage output by each induction electrode pair and the induced voltage output by the detection electrode plate 3 is: ; ; in, is the induced voltage output by each pair of inductive plates, is the gain of the capacitive sensing circuit 8 of the capacitive sensing electronics, To detect the amplitude of the induced voltage output by the plate 3, is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the voltage division ratio from the i-th excitation plate 5 to the detection plate 3, is the amplitude of the i-th excitation signal, is the initial phase of the i-th excitation signal, n=6; S3: randomly select a sensing plate pair in the X-axis direction of the detection plate 3 as the sensing plate pair to be tested, and iteratively adjust the initial phase of each excitation signal based on the optimization algorithm so that the initial phases of two adjacent adjustments satisfy the following formula: ; in, For the When adjusting for the first time, the initial phase of the i-th excitation signal is For the When adjusting for the first time, the initial phase of the i-th excitation signal is is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the learning rate, is the induced voltage output by the inductive plate pair to be tested; S4: Use capacitive sensing electronics to measure the induced voltage output by the inductive plate pair to be tested in real time. When the induced voltage output by the inductive plate pair to be tested measured after two consecutive initial phase adjustments satisfies the following formula, the iteration is stopped to complete the phase synchronization monitoring and adjustment of the multi-channel excitation signal: ; in, For the During the first adjustment, the induction voltage of the induction plate to be tested is For the During the first adjustment, the induction voltage of the induction plate to be tested is Stop parameter for the iteration.

[0032] It should be noted that in actual applications, the center of the electrode cage 1 and the center of the detection electrode 3 are difficult to coincide, and there will be an offset during the assembly process. Generally speaking, the smaller displacement is any value between 10 microns and 20 microns.

[0033] In some embodiments, in step S2, different excitation signals have the same frequency but different initial phases.

[0034] It should be noted that the i-th excitation signal for: ; in, is the amplitude of the i-th excitation signal, is the initial phase of the i-th excitation signal (controllable), The signal angular frequency is a fixed value.

[0035] In some embodiments, the induced voltage output by the detection plate 3 is The expression is: ; in, is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the voltage division ratio from the i-th excitation plate 5 to the detection plate 3, and its size is related to the capacitance distribution of the sensitive probe. is the amplitude of the i-th excitation signal, is the initial phase of the i-th excitation signal, is the angular frequency of the excitation signal, n=6.

[0036] Theoretically, when the initial phase When the following equation is satisfied, the induced voltage on the detection plate 3 is The maximum amplitude is: ; At this time, the induced voltage on the detection plate 3 The amplitude can be expressed as: ; At this time, the scale factor of the capacitance sensing circuit 8 is maximum ; At this time, the output voltage of the sensing plate pair to be tested read by the capacitance sensing circuit 8 is Maximum is: ; in, represents the gain of the capacitance sensing circuit 8, represents the input of the differential capacitance of the sensing plate pair, K is the scale factor, is the amplitude of the i-th excitation signal, It is the voltage division ratio from the i-th excitation plate 5 to the detection plate 3.

[0037] It should be noted that, considering the influence of measurement noise, the induction voltage output by the induction plate to be measured If there is fluctuation, the iteration is stopped when the induced voltages output by the two inductive plates to be tested meet the formula iteration stop parameter. The iteration stop parameter is related to the output voltage fluctuation of the capacitance sensing circuit 8 and can be set according to the specific situation.

[0038] In some embodiments, in step S3, the optimization algorithm is a gradient ascent algorithm, Newton's method or a neural network method.

[0039] The present invention first fixes the detection plate 3 so that it deviates from the center position of the electrode cage 1 with a slight displacement, records the output voltage of the capacitive displacement sensor, and designs an optimization algorithm to adjust the initial phase of each excitation signal to maximize the output voltage of the capacitive displacement sensor, so that the initial phase of the excitation signal offsets the phase delay caused by factors such as line delay, thereby achieving the purpose of synchronizing the phase of the excitation signal, and then the synthetic signal acting on the detection plate 3 reaches the designed maximum value, ensuring that the capacitive sensing sensitivity is consistent with the designed value. Here, the initial phase of the multi-channel excitation signal is adjusted by the optimization algorithm to offset the influence of factors such as the structural design of the sensitive probe of the capacitive displacement sensor and line delay on the phase delay of the multi-channel excitation signal, thereby increasing the scale factor of the capacitive displacement sensor and improving the sensitivity.

[0040] The core idea of ​​the present invention is to solve the problem that the sensitivity of the capacitive displacement sensor is lower than the design value by adjusting the phase of the multi-channel excitation signal in real time. The excitation signal phase synchronization mentioned in the present invention does not refer to the phase synchronization when the excitation signal is output from the DA, but the phase synchronization when it acts on the detection plate 3.

[0041] Example 1 The multi-channel excitation signal phase synchronization monitoring and adjustment method of the capacitive displacement sensor of the present invention is applied to a certain type of inertial sensor, and a capacitive sensor stand-alone of a cubic sensitive probe is taken as an example to introduce a specific embodiment of the present invention in detail.

[0042] A test platform is built to keep the vacuum tank 7 in a high vacuum environment, and temperature control and environmental monitoring are turned on (implemented by the vacuum system 7). The center of the electrode cage 1 is controlled by the six-legged adjustment platform 4 to be close to the center of the detection electrode plate 3 and maintain a small offset.

[0043] Considering that the excitation electrode 5 is not arranged in the x-axis direction of the detection electrode 3, that is, the excitation electrode 5 is not arranged in the x-axis direction of the sensitive probe (based on all the components in the vacuum tank 7 constituting the sensitive probe), only a small offset is maintained in the x-axis direction (the center of the electrode cage 1 is relative to the center of the detection electrode 3) to reduce the influence of the position offset of the detection electrode 3 on the capacitance of the excitation electrode 5, and reduce the voltage divider ratio of the excitation electrode voltage caused by the deviation of the detection electrode 3 from the center position In order to avoid the influence of the above, the sensing plate 2 in the x-axis direction is also used to read the voltage data of the capacitive displacement sensor to improve the accuracy of the test.

[0044] Step 2: Capacitive sensing electronics (combination of capacitive sensing circuit 8 and data processing device 9) outputs 6 voltage excitation signals Acts on the excitation plate 5.

[0045] Each excitation signal has the same frequency and different initial phases. The expression of the excitation signal is: ; in, is the amplitude of the i-th excitation signal, is the initial phase of the i-th excitation signal (controllable), is the angular frequency of the excitation signal, which is a fixed value. is the i-th excitation signal.

[0046] At this time, the induced voltage on the detection plate 3 obtained by the combined action of the excitation voltages is for: ; in, is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the voltage division ratio from the i-th excitation electrode plate 5 to the detection electrode plate 3, and its size is related to the capacitance distribution of the sensitive probe. When the relative position of the detection electrode plate 3 and the electrode cage 1 is fixed, is a fixed value.

[0047] Step 3: Capacitive sensing electronics continuously measures the differential capacitive sensing output voltage of a pair of sensing plates 2 in the X-axis direction of the sensitive probe .

[0048] Capacitive sensing output voltage It is expressed as: ; in, is the gain of the capacitance sensing circuit 8 corresponding to a pair of sensing plates (sensing plate pair to be measured) in the X-axis direction, It represents the differential capacitance input of a pair of sensing plates 2 in the X-axis direction.

[0049] Step 4: Design optimization algorithm to iteratively adjust the initial phase of each excitation signal .

[0050] In practical applications, the gradient ascent method can be used to solve the problem, and other optimization algorithms can also be used to achieve the same purpose.

[0051] The partial derivative of the initial phase of each excitation signal is calculated, and the gradient calculation process is as follows: ; in, The input is the differential capacitance of the sensing plate pair.

[0052] Initial Phase The update rules are as follows: ; in, is the learning rate, which controls the magnitude of each update, is the induced voltage corresponding to the current excitation signal, and k is the number of iterations.

[0053] Figure 4 It is the phase convergence diagram of each excitation signal. Figure 4 Medium learning rate Select 0.05, the phase offset of each excitation signal is a random value. When the visible iteration exceeds 500 times, the initial phase Converges to a fixed value .

[0054] Step 5: The capacitive sensing electronics continuously measures the output voltage of the sensing plate 2 , for output voltage Sampling is performed, and the iteration is stopped when the sampling of the capacitance sensing circuit 8 satisfies the following formula: It represents the iteration stop condition, which is related to the output voltage fluctuation of the capacitance sensing circuit 8 and can be set according to the specific situation.

[0055] ; Figure 5 This is the capacitive sensing output voltage convergence diagram. Figure 4 The stop condition is , after 200 iterations, the stopping condition is met.

[0056] Considering the output voltage of the capacitor The fluctuation of the output voltage is Perform filtering to improve the accuracy of the optimization algorithm. For example, if mean filtering is used, the iteration cutoff condition is: ; in, is the length of the mean filter sliding window, is the offset within the current mean filter sliding window. Other similar processing methods can produce the same effect.

[0057] Considering that the readout voltage of the capacitive displacement sensor will fluctuate due to various noises, filtering the readout voltage of the capacitive displacement sensor (the output voltage of the sensing plate 2) can achieve better results. The mean filtering algorithm is used here, and other filtering algorithms can achieve the same effect.

[0058] In addition, the present invention takes into account the characteristic that the excitation electrode plates are not distributed in the x-axis direction in the design of the sensitive probe structure, and selects the output voltage signal of the x-axis capacitive displacement sensor as the target signal, thereby reducing the influence of the excitation electrode plate 5 on the sensing electrode plate 2 and improving the test accuracy. If two differential capacitors in the x-axis direction are selected for simultaneous detection, the accuracy of the test results can be improved, but the idea is consistent with this method.

[0059] At the same time, a slight position offset in the x-axis direction has little effect on the capacitance distribution of the excitation plate 5 in the sensitive probe, which makes the voltage division ratio from the voltage applied on the excitation plate 5 to the detection plate 3 basically unchanged, increasing the applicability and accuracy of the test method. If the voltage division ratio and initial phase at different positions are tested by changing the position offset of the detection plate 3, and a lookup table is designed to compensate for the phase, the test effect will also be improved, and its basic idea is consistent with the present invention.

[0060] 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 the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0061] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for synchronously monitoring and adjusting the phase of a multi-channel excitation signal, which is used to realize synchronously monitoring and adjusting the phase of a multi-channel excitation signal of a capacitive displacement sensor, characterized in that: The specific steps include: S1: Build the test platform, which includes sensitive probes and capacitive sensing electronics; The sensitive probe includes an electrode cage, a six-legged adjustment platform, a plurality of excitation plates and a plurality of induction plates fixed on the electrode cage in an insulated manner, and a detection plate located in the electrode cage, wherein the six-legged adjustment platform drives the electrode cage to move with six degrees of freedom relative to the detection plate; S2: In a vacuum environment, the electrode cage is moved along the X-axis direction of the detection electrode plate, so that the center of the electrode cage has a small displacement in the X-axis direction of the detection electrode plate relative to the center of the detection electrode plate. The capacitive sensing electronics transmits different excitation signals to each excitation electrode plate, so that the detection electrode plate and each induction electrode plate pair generate an induced voltage. The relationship between the amplitude of the induced voltage output by each induction electrode plate pair and the induced voltage output by the detection electrode plate is: ； ； in, is the induced voltage output by each pair of inductive plates, is the gain of the capacitive sensing circuit of the capacitive sensing electronics, To detect the amplitude of the induced voltage output by the plate, is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the voltage divider ratio from the i-th excitation plate to the detection plate, is the amplitude of the i-th excitation signal, is the initial phase of the i-th excitation signal, n=6; S3: randomly select a sensing plate pair in the X-axis direction of the detection plate as the sensing plate pair to be tested, and iteratively adjust the initial phase of each excitation signal based on the optimization algorithm so that the initial phases of two adjacent adjustments satisfy the following formula: ； in, For the When adjusting for the first time, the initial phase of the i-th excitation signal is For the When adjusting for the first time, the initial phase of the i-th excitation signal is is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the learning rate, is the induced voltage output by the inductive plate pair to be tested; S4: Use capacitive sensing electronics to measure the induced voltage output by the inductive plate pair to be tested in real time. When the induced voltage output by the inductive plate pair to be tested measured after two consecutive initial phase adjustments satisfies the following formula, the iteration is stopped to complete the phase synchronization monitoring and adjustment of the multi-channel excitation signal: ； in, For the During the first adjustment, the induction voltage of the induction plate to be tested is For the During the first adjustment, the induction voltage of the induction plate to be tested is Stop parameter for the iteration.

2. The phase synchronization monitoring and adjustment method of a multi-channel excitation signal according to claim 1, characterized in that: In step S1, the capacitive sensing electronics includes a capacitive sensing circuit and a data processing device connected in sequence, the capacitive sensing circuit is used to transmit an excitation signal to each excitation plate and measure the induced voltage output by the induction plate pair to be tested, and the data processing device is used to run an optimization algorithm; The sensitive probe also includes a fixing device and a vacuum tank, wherein the fixing device, the electrode cage, the six-legged adjustment platform, a plurality of excitation plates, a plurality of induction plates, the electrode cage and the detection plates are all placed in the vacuum tank; The fixing device suspends the detection electrode plate in the electrode cage, a plurality of induction electrodes are uniformly distributed on the electrode cage in an insulated form around the detection electrode plate, and a plurality of excitation electrodes are symmetrically arranged on the electrode cage in an insulated form along the Y-axis direction and the Z-axis direction of the detection electrode plate.

3. The phase synchronization monitoring and adjustment method of multi-channel excitation signals according to claim 2, characterized in that: The detection electrode plate is a cube, the electrode cage is a cube with a hollow interior, and the capacitive sensing circuit is connected to the sensing electrode plate to be detected and the excitation electrode plate respectively through cables.

4. The phase synchronization monitoring and adjustment method of a multi-channel excitation signal according to claim 1, characterized in that: In step S2, different excitation signals have the same frequency but different initial phases.

5. The phase synchronization monitoring and adjustment method of multi-channel excitation signals according to claim 1, characterized in that: In step S2, the induced voltage output by the plate is detected The expression is: ； in, is the phase shift caused by the line delay of the i-th excitation signal and the sensitive probe structure design, is the voltage divider ratio from the i-th excitation plate to the detection plate, is the amplitude of the i-th excitation signal, is the initial phase of the i-th excitation signal, is the angular frequency of the excitation signal, n=6.

6. The phase synchronization monitoring and adjustment method of multi-channel excitation signals according to claim 1, characterized in that: In step S2, the smaller displacement is any value between 10 micrometers and 20 micrometers.

7. The phase synchronization monitoring and adjustment method of a multi-channel excitation signal according to claim 1 or 2, characterized in that: In step S3, the optimization algorithm is a gradient ascent algorithm, Newton's method or a neural network method.

8. The phase synchronization monitoring and adjustment method of multi-channel excitation signals according to claim 1, characterized in that: In step S3: 。 9. The method for phase synchronization monitoring and adjustment of multi-channel excitation signals according to claim 2, characterized in that: In step S4, the output voltage of the inductive plate pair to be tested is : ； in, represents the gain of the capacitive sensing circuit, represents the input of the differential capacitance of the sensing plate pair, K is the scale factor, is the amplitude of the i-th excitation signal, It is the voltage divider ratio from the i-th excitation plate to the detection plate.

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