Variable area capacitive sensor displacement measurement method for interference suppression

Abstract

The application discloses a variable-area capacitive sensor displacement measurement method for interference suppression and relates to the technical field of precise displacement detection, and comprises the following steps: S1, acquiring a differential capacitance array by using a variable-area capacitive sensor; S2, acquiring a capacitance change signal by using the differential capacitance array; and S3, performing differential processing on the capacitance change signal to acquire a variable-area capacitive sensor displacement measurement result. The application arranges multiple groups of differential capacitance pairs in the same direction, adopts a processing mode of odd-even grouping and parallel connection and then differential output, so that the output signal of the sensor linearly increases with the increase of the number of differential capacitance pairs, and the sensitivity of measurement is effectively improved. The structure can not only quickly and accurately respond to slight displacement changes, but also realize higher-precision detection capability without significantly increasing the complexity of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of precision displacement detection, and particularly relates to a variable-area capacitive sensor displacement measurement method for suppressing interference. BACKGROUND

[0002] A capacitive sensor is a commonly used sensing device that reflects the measured physical quantity (such as displacement, pressure, acceleration, etc.) by detecting the change in capacitance. Its working principle is to use the change of the measured object to cause the change of the geometric parameters (such as the plate area, the distance or the medium characteristics) of the capacitor, thereby causing the change of the capacitance value. With the advantages of simple structure, non-contact measurement, low power consumption, fast response speed, etc., the capacitive sensor has been widely used in consumer electronics, industrial control, medical equipment, aerospace and other fields.

[0003] Among various capacitive sensors, the variable-area capacitive sensor is often used for precision displacement measurement due to its high sensitivity to displacement changes. This sensor is usually composed of two metal plates, one of which is a fixed plate and the other is a movable plate. When an external physical quantity acts on the movable plate, the overlapping area between the two plates will change, causing a corresponding change in the capacitance value. By measuring the change in capacitance, the size of the measured displacement can be derived, achieving non-contact high-precision detection. However, in practical applications, the traditional single-capacitance sensor has many limitations. Since it only relies on a single capacitance unit for measurement, the output signal amplitude is small, and it is easily affected by parasitic capacitance and environmental noise, resulting in a low overall signal-to-noise ratio, which limits the measurement accuracy and stability. At the same time, this type of sensor lacks an effective common-mode rejection mechanism and is sensitive to external interference factors such as temperature drift and power supply voltage fluctuations. Long-term use may cause performance degradation, affecting the reliability of the system.

[0004] Therefore, there is an urgent need for a variable-area capacitive sensor displacement measurement method for suppressing interference to meet the needs of the precision displacement detection field. SUMMARY

[0005] The purpose of the present application is to provide a variable-area capacitive sensor displacement measurement method for suppressing interference, which arranges multiple capacitive pairs in the same plane and the same direction, processes the data differentially, improves the sensitivity of the system, and enhances the anti-interference ability.

[0006] To achieve the above purpose, the present application provides a variable-area capacitive sensor displacement measurement method for suppressing interference, comprising the following steps:

[0007] S1, using a variable-area capacitive sensor, obtaining a differential capacitance array;

[0008] S2, acquiring a capacitance change signal by using the differential capacitance array;

[0009] S3, performing differential processing on the capacitance change signal to acquire a variable-area capacitive sensor displacement measurement result.

[0010] Optionally, the variable-area capacitive sensor comprises a plurality of differential capacitance pairs, each of which is composed of a plurality of fixed plates and movable plates.

[0011] Optionally, S1, acquiring a differential capacitance array by using a variable-area capacitive sensor, comprises:

[0012] Based on the variable-area capacitive sensor, a plurality of differential capacitance pairs are arranged in a straight line direction on the same plane, wherein the movable plates of the plurality of differential capacitance pairs are integrally arranged on the same sliding layer, and the movable plates of the plurality of differential capacitance pairs move synchronously under the action of an external force.

[0013] The movable plates of the odd-numbered groups and the movable plates of the even-numbered groups in the plurality of differential capacitance pairs are staggered to obtain a differential capacitance array.

[0014] Optionally, S2, acquiring a capacitance change signal by using the differential capacitance array, comprises:

[0015] The movable plates of the odd-numbered groups in the differential capacitance array are processed in parallel to obtain a first output end;

[0016] The movable plates of the even-numbered groups in the differential capacitance array are processed in parallel to obtain a second output end;

[0017] According to the displacement of the movable plates of the variable-area capacitive sensor under the action of an external force, the total capacitance change of the odd-numbered groups and the total capacitance change of the even-numbered groups are respectively acquired based on the first output end and the second output end.

[0018] The total capacitance change of the odd-numbered groups and the total capacitance change of the even-numbered groups are acquired as a capacitance change signal.

[0019] Optionally, the calculation formula of the total capacitance change of the odd-numbered groups is as follows:

[0020]

[0021] Wherein, Δ C odd is the total capacitance change of the odd-numbered groups, odd is an odd number, C R,i is the capacitance formed by the movable plate and the fixed plate on the right side in the first i group of odd-numbered groups, C L,i is the capacitance formed by the movable plate and the fixed plate on the right side in the second iThe capacitance formed by the moving plate and the fixed plate on the left side in the odd array. N odd For odd-numbered differential capacitor pairs, k It is the proportionality coefficient, ∆ x This represents the displacement of the moving plate under the action of an external force.

[0022] Optionally, the formula for calculating the change in the total capacitance of the even array is as follows:

[0023]

[0024] Where, ∆ C even For even-numbered arrays, the total capacitance change is... even Even number, C R,i For the first i The capacitance formed by the moving plate and the fixed plate on the right side in the odd array. C L,i For the first i The capacitance formed by the moving plate and the fixed plate on the left side in the odd array. N even The number of even-numbered differential capacitor pairs. k It is the proportionality coefficient, ∆ x This represents the displacement of the moving plate under the action of an external force.

[0025] Optionally, S3, differential processing is performed on the capacitance change signal to obtain the displacement measurement result of the variable area capacitive sensor, including:

[0026] The capacitance change signal is differentially processed to obtain the capacitance change amount of the differential output;

[0027] Based on the capacitance change of the differential output combined with the sensitivity, the displacement measurement result of the variable area capacitive sensor is obtained.

[0028] Optionally, the capacitance change signal is differentially processed to obtain the capacitance change of the differential output, calculated as follows:

[0029]

[0030] Where, ∆ C diff ∆ represents the change in capacitance of the differential output. C odd For the change in total capacitance of odd-numbered arrays, ∆ C even For even-numbered arrays, the total capacitance change is... N This refers to the number of differential capacitor pairs. k It is the proportionality coefficient, ∆ x This represents the displacement of the moving plate under the action of an external force.

[0031] Optionally, the sensitivity calculation formula is as follows:

[0032]

[0033] Wherein, S is the sensitivity, and C diff is the differential output capacitance change, and x is the displacement of the moving electrode plate under the action of external force.

[0034] Compared with the closest prior art, the present application has the beneficial effects of:

[0035] The present application has innovative improvements in structural design and signal processing methods, thereby significantly improving the overall performance of the sensor. By arranging multiple sets of differential capacitance pairs in the same direction and using the odd-even grouping parallel connection and then performing differential output processing, the output signal of the sensor increases linearly with the number of differential capacitance pairs, effectively improving the measurement sensitivity. This structure not only responds quickly and accurately to small displacement changes, but also realizes higher detection accuracy without significantly increasing system complexity.

[0036] In addition, due to the use of differential output mechanism, the present application has good suppression ability when facing common-mode interference factors such as temperature drift, power voltage fluctuation, material thermal expansion, etc. These external disturbances usually have similar effects on all capacitive units, but they will be cancelled out during differential output, thereby significantly improving the stability and long-term reliability of the system, and is particularly suitable for application scenarios with complex working environment and high stability requirements. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0038] Figure 1 It is a flow chart of a variable-area capacitive sensor displacement measurement method for suppressing interference according to an embodiment of the present application;

[0039] Figure 2 It is a schematic diagram of a capacitive sensor electrode plate according to an embodiment of the present application;

[0040] Figure 3 It is a differential area capacitive sensor structure diagram according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0042] The terms used in the embodiments of the present application are only used for explaining the specific embodiments of the present application, and are not intended to limit the present application.

[0043] As shown in the accompanying drawings, Figure 1 The embodiments of the present application provide a variable-area capacitive sensor displacement measurement method for suppressing interference, comprising:

[0044] S1, acquiring a differential capacitance array by using a variable-area capacitive sensor;

[0045] When the variable-area capacitive sensor is used to acquire the differential capacitance array, a plurality of groups of differential capacitance pairs are arranged in a straight line direction on the same plane N Each group of capacitance pairs is composed of two fixed plates and one movable plate, all movable plates are integrated in the same sliding layer and can move synchronously, and the odd-numbered group and the even-numbered group of movable plates are staggered to form a symmetric physical layout. This process lays a foundation for subsequent improvement of sensitivity by increasing the number of differential capacitance pairs N , and the symmetric layout design is helpful for subsequent suppression of common-mode interference, and provides structural support for high precision and high stability of the overall measurement system.

[0046] S2, acquiring a capacitance change signal by using the differential capacitance array;

[0047] When the differential capacitance array constructed above is used to acquire the capacitance change signal, all the odd-numbered group of movable plates are connected in parallel as an output end A, and all the even-numbered group of movable plates are connected in parallel as an output end B. When the movable plates move due to displacement, the facing area with the fixed plates changes, resulting in corresponding capacitance change signals at the two ends A and B. Since a plurality of groups of capacitance pairs are connected in parallel, the output signal amplitude is larger than that of the traditional single capacitive sensor, the influence of parasitic capacitance and environmental noise is reduced, and the signal-to-noise ratio is improved, providing a more reliable signal source for subsequent accurate measurement.

[0048] S3, performing differential processing on the capacitance change signal to acquire a variable-area capacitive sensor displacement measurement result.

[0049] The capacitance change signals acquired at outputs A and B are differentially processed, i.e., the difference between the two signals is calculated to obtain the final capacitance change. The displacement measurement result is then derived using the sensitivity formula. This differential processing process makes the system sensitivity correlated with the number of differential capacitors. N ( N The difference is proportional to even numbers, which significantly improves the measurement sensitivity and enables a fast and accurate response to minute displacement changes. At the same time, common-mode interference such as temperature drift and power supply voltage fluctuations are completely canceled in differential processing, which effectively enhances the anti-interference capability of the system, ensures the accuracy and stability of the measurement results, and improves the reliability of the system in long-term operation.

[0050] Furthermore, the variable area capacitive sensor includes several capacitor pairs, each of which consists of several fixed plates and a moving plate.

[0051] Specifically, the differential variable area capacitive sensor consists of a fixed plate and a moving plate, with an initial capacitance value... C 0 is:

[0052]

[0053] in, ε The total dielectric constant is A The area of ​​the two plates facing each other. d The distance between the plates;

[0054] A variable area capacitive sensor includes multiple capacitor pairs, each consisting of two fixed plates and one moving plate.

[0055] As one possible implementation, in the above embodiments, step S1 may specifically include the following steps:

[0056] Based on the variable area capacitive sensor, several differential capacitor pairs are arranged in a straight line on the same plane, wherein the moving plates of several differential capacitor pairs are integrated in the same sliding layer, and the moving plates of several capacitor pairs move synchronously under the action of external force.

[0057] A differential capacitor array is obtained by alternating the moving plates of the odd-numbered array and the moving plates of the even-numbered array in several differential capacitor pairs.

[0058] Specifically, all moving plates are integrated on the same sliding layer and can move synchronously under the action of external force.

[0059] Initially, the moving plate is located in the center, with an area equal to that of the two fixed plates on the left and right. Figure 2 As shown, the corresponding capacitance value is:

[0060] C L =C R = C 0

[0061] wherein, C L is the capacitance formed by the moving electrode plate and the left fixed electrode plate, C R is the capacitance formed by the moving electrode plate and the right fixed electrode plate.

[0062] The moving electrode plates of the odd-numbered groups and the moving electrode plates of the even-numbered groups are arranged in a straight line on the same plane. N The differential capacitance pairs form a differential capacitance array. When constructed, the moving electrode plates of the odd-numbered groups and the moving electrode plates of the even-numbered groups are arranged in an interlaced manner, and the physical layout is symmetrical, so as to realize spatial periodic sampling of the target signal.

[0063] As a possible implementation, in the above embodiment, step S2 can specifically include the following steps:

[0064] S2-1, parallel processing the moving electrode plates of the odd-numbered groups in the differential capacitance array to obtain a first output end;

[0065] S2-2, parallel processing the moving electrode plates of the even-numbered groups in the differential capacitance array to obtain a second output end;

[0066] S2-3, based on the first output end and the second output end, respectively obtaining the total capacitance change of the odd-numbered groups and the total capacitance change of the even-numbered groups according to the displacement of the moving electrode plate under the action of the external force, wherein the capacitance change corresponding to the first output end is the total capacitance change of the odd-numbered groups, and the capacitance change corresponding to the second output end is the total capacitance change of the even-numbered groups;

[0067] S2-4, obtaining the total capacitance change of the odd-numbered groups and the total capacitance change of the even-numbered groups as the capacitance change signal.

[0068] Specifically, all the moving electrode plates of the odd-numbered groups are connected in parallel as one output end A, and all the moving electrode plates of the even-numbered groups are connected in parallel as another output end B.

[0069] When the moving electrode plate moves to the right by Δ x , the opposite area changes, thereby causing the capacitance change, and the calculation formula is as follows:

[0070]

[0071] wherein, Δ C is the capacitance change amount, k is a proportional coefficient (depending on the size of the electrode plate, the dielectric constant, etc.), indicating the capacitance change caused by unit displacement, and Δ x is the displacement of the moving electrode plate under the action of the external force.

[0072] The total capacitance change of the odd-numbered groups isC odd is:

[0073]

[0074] wherein, odd is an odd number, C R,i is the first i group of odd numbers, C L,i is the first i group of odd numbers, N odd is the number of differential capacitor pairs of the odd number group.

[0075] total capacitance change of the even number group C even is:

[0076]

[0077] wherein, even is an even number, N even is the number of differential capacitor pairs of the even number group.

[0078] As a possible implementation, in the above embodiment, step S3 can specifically include the following steps:

[0079] S3-1, differentially process the capacitance change signal to obtain a differential output capacitance change;

[0080] S3-2, based on the differential output capacitance change and the sensitivity, obtain a variable-area capacitive sensor displacement measurement result.

[0081] Specifically, the A and B signals are differentially processed to obtain a final output signal, as shown in Figure 3 .

[0082] N is an even number, then: N odd = N even = N / 2;

[0083] The final output signal is differentially processed to obtain a differential output capacitance change C diff is:

[0084]

[0085] sensitivity SThe sensitivity is defined as the ratio of the output signal change to the input displacement change:

[0086]

[0087] Substitute the above results:

[0088]

[0089] It can be seen that the sensitivity is proportional to the number of differential capacitance pairs N , and using more differential capacitance pairs can significantly improve the sensitivity, and the sensitivity is linearly improved with each additional pair.

[0090] The common mode interference term is introduced δC , which represents the same external disturbance (such as temperature drift, voltage fluctuation, etc.) received by all capacitance pairs. Taking N as an even number as an example, at this time:

[0091]

[0092] Where, Δ C cm is the common mode capacitance change.

[0093] The total capacitance change of the odd group is:

[0094]

[0095] The total capacitance change of the even group is:

[0096]

[0097] The differential output is:

[0098]

[0099] It can be seen that the common mode interference term δC is completely cancelled in the differential process, achieving good anti-interference ability.

[0100] Those skilled in the art should understand that embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0101] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0102] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0103] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0104] Finally, it should be noted that the above-mentioned embodiments are merely used to illustrate the technical solutions of the present application, but are not intended to limit the present application. Although the present application has been described in detail with reference to the above-mentioned embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced, and any modification or replacement without departing from the spirit and scope of the present application should be covered within the protection scope of the claims of the present application.

Claims

1. A variable-area capacitive sensor displacement measurement method for interference suppression, characterized by, The method comprises the steps of: S1, acquiring a differential capacitance array by using a variable-area capacitive sensor; The variable-area capacitive sensor comprises a plurality of differential capacitance pairs, each of which is composed of a plurality of fixed plates and movable plates; S2, acquiring a capacitance change signal by using the differential capacitance array; S2, acquiring a capacitance change signal by using the differential capacitance array, comprising: parallel processing the movable plates of the odd-numbered groups in the differential capacitance array to obtain a first output end; parallel processing the movable plates of the even-numbered groups in the differential capacitance array to obtain a second output end; acquiring the total capacitance change of the odd-numbered groups and the total capacitance change of the even-numbered groups based on the displacement of the movable plates of the variable-area capacitive sensor under the action of an external force and the first output end and the second output end, respectively; acquiring the total capacitance change of the odd-numbered groups and the total capacitance change of the even-numbered groups as the capacitance change signal; S3, differentially processing the capacitance change signal to obtain a variable-area capacitive sensor displacement measurement result.

2. A variable area capacitive sensor displacement measurement method for interference suppression according to claim 1, characterized in that, S1, acquiring a differential capacitance array by using a variable-area capacitive sensor, comprising: based on the variable-area capacitive sensor, arranging a plurality of differential capacitance pairs in a straight line direction on the same plane, wherein the movable plates of the plurality of differential capacitance pairs are integrally arranged on the same sliding layer, and the movable plates of the plurality of differential capacitance pairs move synchronously under the action of an external force; staggered arrangement of the movable plates of the odd-numbered groups and the movable plates of the even-numbered groups in the plurality of differential capacitance pairs to obtain a differential capacitance array.

3. A variable area capacitive sensor displacement measurement method for interference suppression as claimed in claim 1, wherein, The calculation formula of the total capacitance change of the odd-numbered groups is as follows: Where, ∆ C odd For odd-numbered arrays, the total capacitance change is... odd It is an odd number. C R,i For the first i The capacitance formed by the moving plate and the fixed plate on the right side in the odd array. C L,i For the first i The capacitance formed by the moving plate and the fixed plate on the left side in the odd array. N odd For odd-numbered differential capacitor pairs, k It is the proportionality coefficient, ∆ x This represents the displacement of the moving plate under the action of an external force.

4. A variable area capacitive sensor displacement measurement method for interference suppression as claimed in claim 1, wherein, The calculation formula of the total capacitance change of the even-numbered groups is as follows: wherein, Δ C even is the total capacitance change of the even number, even is the even number, C R,i is the capacitance of the first i group of odd number formed by the moving electrode plate and the right fixed electrode plate, C L,i is the capacitance of the first i group of odd number formed by the moving electrode plate and the left fixed electrode plate, N even is the number of differential capacitance pairs of the even number, k is the proportional coefficient, Δ x is the displacement of the moving electrode plate under the action of external force.

5. A variable area capacitive sensor displacement measurement method for interference suppression as claimed in claim 1, wherein, S3, differentially processing the capacitance change signal to obtain a variable-area capacitive sensor displacement measurement result, comprising: differentially processing the capacitance change signal to obtain a differential output capacitance change; based on the differential output capacitance change and the sensitivity, acquiring a variable-area capacitive sensor displacement measurement result.

6. A variable area capacitive sensor displacement measurement method for interference suppression according to claim 5, wherein, Differentially processing the capacitance change signal to obtain a differential output capacitance change, the calculation formula is as follows: where ΔC is the differential capacitance change C diff is the differential output capacitance change, ΔC C odd is the odd set total capacitance change, ΔC C even is the even set total capacitance change, ΔC N is the differential capacitance pair number, N k is the proportional coefficient, ΔC x is the displacement of the moving electrode plate under the action of external force.

7. A variable area capacitive sensor displacement measurement method for interference rejection according to claim 5, wherein, The sensitivity calculation formula is as follows: wherein, S is the sensitivity, Δ C diff is the differential output capacitance change amount, Δ x is the displacement amount of the movable electrode under the action of an external force.

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