Differential angle sensor with variable area type capacitor structure

Abstract

The utility model belongs to the technical field of sensing measurement, and discloses a differential angle sensor with a variable area type capacitor structure, which comprises two polar plates which are arranged in parallel at an interval, one polar plate is a fixed plate, the other polar plate is a movable plate, the fixed plate comprises a fixed plate electrode I and a fixed plate electrode II, and the movable plate comprises a movable plate electrode; the rotor plate electrode and the stator plate electrode I form a capacitor C1, and the rotor plate electrode and the stator plate electrode II form a capacitor C2; the fixed plate is fixed, the movable plate rotates to form capacitance value changes of the capacitor C1 and the capacitor C2, and measurement of the rotation angle of the movable plate is completed according to the corresponding relation between the capacitance value changes and the angle changes. The sensor is strong in anti-interference capability, high in precision, simple and reliable in structure and low in cost, the sensitivity of the sensor can be improved by improving the excitation signal frequency, and the performance of the sensor is ensured by utilizing an external automatic gain control circuit.

Description

Technical Field

[0001] The utility model belongs to the technical field of sensor measurement, relates to a capacitive angle measurement method, and specifically relates to a differential angle sensor with a variable area capacitor structure. Background Art

[0002] Angular displacement measurement has a wide range of applications in industry, aviation, shipbuilding, etc. According to different measurement principles, it can be divided into photoelectric, magnetoelectric, capacitive, inductive and resistive types.

[0003] Existing angle sensors or angular displacement sensors, such as RVDT rotary variable differential transformer angular displacement sensors, have complex structures, high manufacturing difficulty, and are expensive. Another example is the resistive potentiometer angular displacement sensor, which has high difficulty in winding the potentiometer and poor vibration resistance of the mechanical contacts. Utility Model Content

[0004] Purpose of the utility model:

[0005] In order to solve the above problems, a differential angle sensor with a variable area capacitor structure is provided. The sensor works stably and reliably, is easy to implement, has good economic benefits, and can eliminate the measurement error of the sensor.

[0006] Utility model technical solution:

[0007] A differential angle sensor with a variable area capacitor structure comprises two parallel and spaced plates, one of which is a fixed plate and the other is a movable plate, wherein the fixed plate comprises a fixed plate electrode 1 and a fixed plate electrode 2, and the movable plate comprises a movable plate electrode; the movable plate electrode and the fixed plate electrode 1 form a capacitor C1, and the movable plate electrode and the fixed plate electrode 2 form a capacitor C2; the fixed plate is fixed, and the movable plate rotates to form a change in the capacitance value of capacitors C1 and C2, and the measurement of the rotation angle of the movable plate is completed according to the corresponding relationship between the change in capacitance value and the change in angle.

[0008] Furthermore, the stator and the rotor have the same external structural dimensions, both are PCB boards with a thickness of 1 mm, and the stator electrode 1, the stator electrode 2 and the rotor electrode are all copper-clad PCB boards.

[0009] Furthermore, through holes are provided in the centers of the stator and the moving plate, the central axis passes through the through holes of the two electrode plates, the copper-clad electrodes face each other, the electrode gap is no more than 1 mm, and the entire sensor is encapsulated in a metal shell.

[0010] Furthermore, the copper-clad parts of the stator electrode 1 and the stator electrode 2 are 90° sectors with the same shape and area; the stator electrode 1 and the stator electrode 2 are symmetrically arranged on the stator.

[0011] Furthermore, the moving electrode is a 180° semicircle, and the semicircle of the moving electrode has the same sector radius r as the first stator electrode and the second stator electrode.

[0012] Furthermore, the radius r≤50mm.

[0013] Furthermore, the sensor composed of the two parallel plates is generally encapsulated in a metal shell, the fixed plate is fixedly connected to the shell, the moving plate can be connected to the central axis by a bearing, the electrodes are not connected to the metal shell, and the three electrodes are respectively led out through welding wires.

[0014] Furthermore, the installation of the two parallel plates should ensure coaxiality and parallelism.

[0015] Furthermore, the medium between the two parallel plates is generally air, and other non-conductive media may also be used in special cases. The medium is preferably one with a large dielectric constant and good temperature stability.

[0016] A measurement method of a differential angle sensor based on dielectric capacitance:

[0017] The capacitance of a capacitor composed of two parallel plates is: C = εS / d, where ε is the dielectric constant of the medium, S is the area of ​​the plates, and d is the distance between the plates.

[0018] When the fixed plate is stationary and the moving plate rotates clockwise by an angle of θ (0≤θ≤90°), the capacitance values ​​C1 and C2 will also change.

[0019] The rotation angle θ corresponds to the difference C between the capacitance values ​​C1 and C2. The capacitance value can be measured by an external circuit and converted into an angle signal output, thereby achieving angle measurement.

[0020] Furthermore, the above differential measurement scheme can eliminate the influence of additional capacitance and external interference signals on the measurement accuracy, and has strong anti-interference ability and high measurement accuracy.

[0021] The advantages of the utility model are as follows:

[0022] 1. Aiming at the problems of poor anti-interference ability and low precision of commonly used capacitive angle sensors, the utility model proposes a differential angle sensor with a variable area capacitor structure and a measurement method thereof, which can realize differential measurement through an external measurement circuit, and has the advantages of strong anti-interference ability and high precision; the measurement method and structure are simple, reliable and low cost.

[0023] 2. The capacitive angle sensor of the utility model can measure the capacitance value through an external circuit, convert it into an angle signal output, thereby realizing angle measurement.

[0024] 3. The variable area capacitor structure differential angle sensor of the utility model can also improve the sensitivity of the sensor by increasing the frequency of the excitation signal, and use an external automatic gain control circuit to ensure the performance of the sensor.

[0025] 4. This utility model can be applied to angular displacement measurement equipment such as angle of attack, angle of attack, and sideslip angle of aircraft flight control systems, and is expected to be promoted and applied in the fields of automated control of aviation, aerospace, missile launch, and civil measurement and control equipment, especially the application of measurement equipment such as rudders of aircraft and ships, and azimuth and tilt angles of vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the implementation method of the utility model patent, the following is a brief introduction to the drawings required for use in the implementation method. It should be understood that the following drawings only show certain embodiments of the utility model patent and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the copper cladding of the PCB board of the stator and the moving piece of the utility model;

[0028] Figure 2 This is a principle diagram when the rotating angle of the moving piece of the utility model is θ.

[0029] In the figure: 1 - fixed plate, 2 - movable plate, 3 - fixed plate electrode 1, 4 - fixed plate electrode 2, 5 - movable plate electrode. DETAILED DESCRIPTION

[0030] This section is an embodiment of the utility model, which is used to explain and illustrate the technical solution of the utility model. In the absence of conflict, the embodiments of the utility model and the features in the embodiments can be combined with each other.

[0031] In the description of the present utility model, it is necessary to understand that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating directions or positional relationships are based on the orientations or positional relationships of the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or case 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 utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0032] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be interpreted in a broad sense, for example, it can be a fixed connection, a detachable connection or an integrated connection; it can be a mechanical connection or a point connection; it can be a direct connection or an indirect connection 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 present utility model can be understood by specific circumstances.

[0033] Embodiment 1:

[0034] A differential angle sensor with a variable area capacitor structure comprises two parallel and spaced plates, one of which is a stator 1 and the other is a rotor 2. The stator 1 comprises a stator electrode 1 3 and a stator electrode 2 4, and the rotor comprises a rotor electrode 5. The rotor electrode 5 and the stator electrode 1 3 form a capacitor C1, and the rotor electrode 5 and the stator electrode 2 4 form a capacitor C2. The stator 1 is fixed and the rotor 2 rotates to form a change in the capacitance value of the capacitor C1 and the capacitor C2, and the rotation angle of the rotor 2 is measured according to the corresponding relationship between the change in the capacitance value and the change in the angle.

[0035] The stator 1 and the rotor 2 have the same external structural dimensions and are both made of PCB material with a thickness of 1 mm. The stator electrode 1 3 , the stator electrode 2 4 and the rotor electrode 5 are all copper-clad PCB boards.

[0036] Through holes are provided in the center of the stator 1 and the moving plate 2. The central axis passes through the through holes of the two electrode plates. The copper-clad electrodes face each other, and the electrode gap is no more than 1 mm. The entire sensor is encapsulated in a metal shell.

[0037] The copper-clad parts of the stator electrode 1 3 and the stator electrode 2 4 are 90° sectors with the same shape and area; the stator electrode 1 3 and the stator electrode 2 4 are symmetrically arranged on the stator 1 .

[0038] The moving electrode 5 is a 180° semicircle, and the fan-shaped radius r of the semicircle of the moving electrode 5 is the same as that of the stator electrode 1 3 and the stator electrode 2 4 .

[0039] Radius r≤50mm.

[0040] The sensor composed of two parallel plates is generally encapsulated in a metal shell, the fixed plate is fixedly connected to the shell, the moving plate can be connected to the central axis by a bearing, the electrodes are not connected to the metal shell, and the three electrodes are respectively led out through welding wires.

[0041] The installation of the two parallel plates should ensure coaxiality and parallelism.

[0042] The medium between the two parallel plates is generally air, and other non-conductive media may also be used in special cases. The medium is preferably one with a large dielectric constant and good temperature stability.

[0043] A measurement method of a differential angle sensor based on dielectric capacitance:

[0044] The capacitance of a capacitor composed of two parallel plates is: C = εS / d, where ε is the dielectric constant of the medium, S is the area of ​​the plates, and d is the distance between the plates.

[0045] When the fixed plate is stationary and the moving plate rotates clockwise at an angle of θ0≤θ≤90°, the capacitance values ​​C1 and C2 will also change:

[0046]

[0047]

[0048] After linearization, subtract equation (2) from equation (1) to obtain:

[0049]

[0050] From formula (3), it can be seen that the capacitance difference C is linearly related to the angle θ.

[0051] Where r is the radius of the electrode sector and semicircle.

[0052] The rotation angle θ corresponds to the difference C between the capacitance values ​​C1 and C2. The capacitance value can be measured by an external circuit and converted into an angle signal output, thereby achieving angle measurement.

[0053] The above differential measurement scheme can eliminate the influence of additional capacitance and external interference signals on the measurement accuracy, has strong anti-interference ability and high measurement accuracy.

[0054] Embodiment 2:

[0055] A differential angle sensor with a variable area capacitor structure and a measuring method thereof, comprising two parallel plates, one being a fixed plate and the other being a moving plate.

[0056] The stator includes stator electrode 1 and stator electrode 2, and the rotor includes a rotor electrode. The rotor electrode and stator electrode 1 form a capacitor C1, and the rotor electrode and stator electrode 2 form a capacitor C2. The stator is fixed, and the rotor rotates to form an area change between the rotor electrode and stator electrode 1 and stator electrode 2, thereby changing the capacitance values ​​C1 and C2.

[0057] The sensor adopts a variable area capacitor structure, which changes the capacitance value by changing the area. The change in area corresponds to the change in angle, thereby completing the angle measurement.

[0058] A differential angle sensor with variable area capacitance structure and its measurement method, with examples:

[0059] The radius of the fan-shaped and semicircular copper-clad electrode on the PCB is r = 20 mm = 0.02 m

[0060] Dielectric constant of medium ε=1F / m

[0061] The distance between the two plates is d = 0.001m

[0062] C1=0.2*(90°-θ)(F)

[0063] C2=0.2*θ(F)

[0064] When the angular displacement is 0°, C1≈0.314F, C2=0, C2-C1≈-0.314F

[0065] When the angular displacement is 30°, C1≈0.2093F, C2≈0.1047F, C2-C1≈-0.1046F

[0066] When the angular displacement is 60°, C1≈0.1047F, C2≈0.2093F, C2-C1≈0.1046F

[0067] Theoretically, the angular displacement is proportional to the differential change in dielectric capacitance.

[0068] Application examples of this embodiment:

[0069] Application scenario 1: Used in aircraft angle of attack sensors, as angular displacement measurement sensors for wind vane rotation.

[0070] Application scenario 2: Used in aircraft steering controllers or self-driving car direction controllers as angle measurement sensors such as elevators, rudders or steering wheels.

[0071] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable technicians familiar with the technical field to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. All equivalent changes or modifications made according to the spirit and essence of the utility model should be included in the protection scope of the utility model. The technology, shape, and structure parts not described in detail in the utility model are all well-known technologies.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the utility model, and these modifications or substitutions should be included in the protection scope of the utility model.

Claims

1. A differential angle sensor with a variable area capacitor structure, characterized in that: The invention comprises two parallel and spaced electrode plates, one of which is a fixed plate (1) and the other is a movable plate (2). The fixed plate (1) comprises a fixed plate electrode 1 (3) and a fixed plate electrode 2 (4), and the movable plate comprises a movable plate electrode (5). The movable plate electrode (5) and the fixed plate electrode 1 (3) form a capacitor C1, and the movable plate electrode (5) and the fixed plate electrode 2 (4) form a capacitor C2. The fixed plate (1) is fixed and the movable plate (2) rotates to form a change in the capacitance value of the capacitor C1 and the capacitor C2. The rotation angle of the movable plate (2) is measured according to the corresponding relationship between the change in the capacitance value and the change in the angle.

2. The differential angle sensor with a variable area capacitor structure according to claim 1, characterized in that: The fixed plate (1) and the movable plate (2) have the same external structure and dimensions, and are both made of PCB board with a thickness of 1 mm. The fixed plate electrode 1 (3), the fixed plate electrode 2 (4) and the movable plate electrode (5) are all PCB board copper-clad.

3. The differential angle sensor with a variable area capacitor structure according to claim 2, characterized in that: Through holes are provided at the centers of the fixed plate (1) and the movable plate (2), and the central axis passes through the through holes of the two electrode plates. The copper-clad electrodes face each other, and the electrode gap is no greater than 1 mm. The entire sensor is encapsulated in a metal shell.

4. The differential angle sensor with a variable area capacitor structure according to claim 1, characterized in that: The copper-clad parts of the stator electrode 1 (3) and the stator electrode 2 (4) are 90° sectors with the same shape and area; the stator electrode 1 (3) and the stator electrode 2 (4) are symmetrically arranged on the stator (1).

5. The differential angle sensor with a variable area capacitor structure according to claim 4, characterized in that: The moving plate electrode (5) is a 180° semicircle, and the semicircle of the moving plate electrode (5) has the same sector radius r as the stator electrode 1 (3) and the stator electrode 2 (4).

6. The differential angle sensor with a variable area capacitor structure according to claim 5, characterized in that: Radius r≯50mm.

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