Linear displacement sensor based on electric field self-coupling

Abstract

The application discloses a linear displacement sensor based on electric field self-coupling, which comprises a moving ruler base body and a fixed ruler base body, one or more pairs of pole units are arranged on the side surface of the moving ruler base body and face the direction of the fixed ruler base body, the pairs of pole units comprise at least three groups of sensing electrode groups which are arranged at intervals along the length direction of the moving ruler base body, each group of sensing electrode groups comprises one excitation electrode and one induction electrode which are arranged at intervals along the length direction of the moving ruler base body, a plurality of modulation unit groups are arranged on the side surface of the fixed ruler base body and face the direction of the moving ruler base body, all the pairs of pole units on the moving ruler base body can correspond to the same number of adjacent modulation unit groups on the fixed ruler base body along the length direction of the fixed ruler base body, each modulation unit group comprises one modulation unit F and one modulation unit G, and the modulation unit F can correspond to at least one group of sensing electrode groups in the pairs of pole units along the length direction of the fixed ruler base body.

Description

Technical Field

[0001] This invention relates to the field of measurement and sensing technology, and specifically to a linear displacement sensor based on electric field self-coupling. Background Technology

[0002] With the rapid development of industrial technology, the requirements for precision displacement measurement technology are becoming increasingly stringent. As one of the three fundamental pillars of modern information technology, sensor technology's performance is closely related to its measurement results. The time-grating displacement sensor is a displacement sensor independently developed and manufactured, realizing the measurement of spatial quantities from time quantities.

[0003] A prior art patent discloses a linear displacement sensor based on a single-row multilayer structure using an electric field-type time grating (publication number CN103822571A). This sensor uses a high-frequency clock pulse as the measurement reference and employs an alternating electric field constructed from parallel-plate capacitors to directly couple the required traveling wave signal, thus enabling high-precision displacement measurement over a large range. However, the moving and fixed scales of this sensor require separate leads. As the fixed scale range increases, the internal resistance of the leads on the fixed scale increases, limiting the sensor's measurement range. Furthermore, the installation of the signal output line is cumbersome, leading to reduced sensor reliability. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a linear displacement sensor based on electric field self-coupling that is simple and reliable in structure, can realize passive sensing of fixed-length substrate, and solve the problem of excessive internal resistance caused by fixed-length substrate lead wire, thereby limiting the measurement range.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A linear displacement sensor based on electric field self-coupling includes a movable scale base and a fixed scale base arranged opposite to and parallel to each other. The side surfaces of the movable scale base and the fixed scale base opposite to each other are parallel to each other and have a gap. One or more counter pole units are arranged on the side surface of the movable scale base facing the direction of the fixed scale base. The counter pole unit includes at least three groups of sensing electrodes arranged at intervals along the length direction of the movable scale base. Each group of sensing electrodes includes an excitation electrode and a sensing electrode arranged at intervals along the length direction of the movable scale base. The spacing between the excitation electrode and the sensing electrode in each group of sensing electrodes is the same. All excitation electrodes and sensing electrodes are arranged alternately along the length direction of the movable scale base.

[0007] When there is only one counter pole unit, the multiple sets of sensing electrodes in the counter pole unit are evenly spaced along the length of the moving scale substrate; when there are multiple counter pole units, all the counter pole units are evenly spaced along the length of the moving scale substrate, and the multiple sets of sensing electrodes in the counter pole unit are evenly spaced along the length of the moving scale substrate. The excitation electrodes located at the positions in the counter pole unit along the length of the moving scale substrate are electrically connected to the excitation electrodes at the corresponding positions in the other counter pole units along the length of the moving scale substrate. All the sensing electrodes are electrically connected together.

[0008] On the fixed-scale substrate, on one side facing the movable-scale substrate, there are several modulation unit groups arranged along the length of the fixed-scale substrate. All the pole pairs on the movable-scale substrate can correspond to the same number of adjacent modulation unit groups on the fixed-scale substrate along the length of the fixed-scale substrate, and each pole pair can correspond to one modulation unit group. Each modulation unit group includes a modulation unit F and a modulation unit G. The modulation unit F and the modulation unit G are made of different materials. All the modulation units F and the modulation unit G are arranged alternately along the length of the fixed-scale substrate. The modulation unit F can correspond to at least one set of sensing electrode groups in the pole pair along the length of the fixed-scale substrate.

[0009] As an optimization, the material of the modulation unit F or the modulation unit G is the same as the material of the fixed-length substrate.

[0010] As an optimization, the modulation unit F, the modulation unit G, and the fixed-length substrate are all made of different materials.

[0011] As an optimization, the modulation unit F and the modulation unit G are located on the same plane, or the plane where the modulation unit F is located is parallel to the plane where the modulation unit G is located.

[0012] As an optimization, the cross-sectional shape of the modulation unit F is a centrally rotationally symmetric figure.

[0013] As an optimization, the cross-sectional shape of the modulation unit F is any one of the following: circular, square, elliptical, rhomboid, double sine, oblique cosine, or double cosine.

[0014] Compared with existing technologies, the present invention has the following advantages: In the present invention, the signal input and output signals of the sensor are both located on the moving scale substrate, which can realize passive sensing of the moving scale substrate, and the measurement range of the fixed scale substrate can be increased at will; the material of the modulation unit on the fixed scale substrate of the sensor can be metal or non-metal, without being limited by the manufacturing materials and processes, and the sensor has a wider detection range; the signal strength output by the sensing unit on the moving scale substrate is not limited by the number of sensing electrodes, the signal transmission efficiency is higher, and the present invention has a wider range of application scenarios and applicability. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural schematic diagram of Embodiment 1 of the present invention;

[0016] Figure 2 This is a schematic diagram of the corresponding structure of the counter pole unit, modulation unit F, and modulation unit G in Embodiment 1 of the present invention;

[0017] Figure 3 This is a schematic diagram of the displacement signal calculation process in Embodiment 1 of the present invention;

[0018] Figure 4 This is a schematic diagram of the corresponding structure of the counter pole unit, modulation unit F, and modulation unit G in Embodiment 2 of the present invention;

[0019] Figure 5 This is a schematic diagram of the corresponding structure of the counter pole unit, modulation unit F, and modulation unit G in Embodiment 3 of the present invention;

[0020] Figure 6 This is a schematic diagram of the corresponding structure of the counter pole unit, modulation unit F, and modulation unit G in Embodiment 4 of the present invention;

[0021] Figure 7 This is a schematic diagram of the corresponding structure of the counter pole unit, modulation unit F, and modulation unit G in Embodiment 5 of the present invention;

[0022] Figure 8 This is a three-dimensional structural diagram of the modulation unit group on the fixed-length substrate in Embodiment 6 of the present invention;

[0023] Figure 9 This is a three-dimensional structural diagram of the modulation unit group on the fixed-length substrate in Embodiment 7 of the present invention;

[0024] Figure 10 This is a three-dimensional structural diagram of the modulation unit group on the fixed-length substrate in Embodiment 8 of the present invention;

[0025] Figure 11 This is a three-dimensional structural diagram of the modulation unit group on the fixed-length substrate in Embodiment 9 of the present invention;

[0026] Figure 12 This is a top view of the fixed-length base in Embodiment 10 of the present invention;

[0027] Figure 13 This is a top view of the fixed-length base in Embodiment 11 of the present invention;

[0028] Figure 14 This is a top view of the fixed-length base in Embodiment 12 of the present invention;

[0029] Figure 15 This is a top view of the fixed-length base in Embodiment 13 of the present invention;

[0030] Figure 16 This is a top view of the fixed-length base in Embodiment 14 of the present invention;

[0031] Figure 17 This is a top view of the fixed-length base in Embodiment 15 of the present invention;

[0032] Figure 18 This is a top view of the fixed-length base in Embodiment 16 of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] Example 1

[0036] like Figure 1 and Figure 2 As shown, the linear displacement sensor based on electric field self-coupling in this specific embodiment includes a movable scale base 1 and a fixed scale base 2 arranged opposite to and parallel to each other. The side surfaces of the movable scale base 1 and the fixed scale base 2 opposite to each other are parallel to each other and have a gap. Two counter pole units are arranged on the side surface of the movable scale base 1 facing the direction of the fixed scale base 2. The counter pole unit includes three groups of sensing electrodes arranged at intervals along the length direction of the movable scale base 1. Each group of sensing electrodes includes an excitation electrode 1-1 and a sensing electrode 1-2 arranged at intervals along the length direction of the movable scale base 1. The spacing between the excitation electrode 1-1 and the sensing electrode 1-2 in each group of sensing electrodes is the same. All the excitation electrodes 1-1 and the sensing electrodes 1-2 are arranged alternately along the length direction of the movable scale base.

[0037] Two counter pole units are arranged at intervals along the length of the movable scale base 1 (if there are three or more counter pole units, these counter pole units are arranged at uniform intervals along the length of the movable scale base 1). Multiple sets of sensing electrodes within the counter pole units are also arranged at uniform intervals along the length of the movable scale base 1. The excitation electrode 1-1 located at each position in the counter pole unit along the length of the movable scale base 1 is electrically connected to the corresponding excitation electrode 1-1 in the other counter pole units along the length of the movable scale base 1. All sensing electrodes 1-2 are electrically connected together. That is, the excitation electrode 1-1 located at the first position in the counter pole unit is connected to all the excitation electrodes 1-1 located at the first position in the other counter pole units. -1 are electrically connected together to form excitation unit group A1. The excitation electrode 1-1, which is the third in the order of the counter electrode unit, is electrically connected to all the excitation electrodes 1-1, which are the third in the order of the other counter electrode units, to form excitation unit group B2. The excitation electrode 1-1, which is the fifth in the order of the counter electrode unit, is electrically connected to all the excitation electrodes 1-1, which are the fifth in the order of the other counter electrode units, to form excitation unit group C3. (If the counter electrode unit includes multiple sets of sensing electrode groups, this continues, with the excitation electrode 1-1, which is the Nth in the order of the counter electrode unit, being electrically connected to all the excitation electrodes 1-1, which are the Nth in the order of the other counter electrode units, to form excitation unit group M.) N Then, the sensing electrodes 1-2 in all the counter pole units are electrically connected together to form a sensing unit group E;

[0038] On the fixed-scale base 2, on one side facing the movable-scale base 1, there are several modulation unit groups arranged along the length of the fixed-scale base 2. All the pole-counting units on the movable-scale base 1 can correspond to the same number of adjacent modulation unit groups on the fixed-scale base 2 along the length of the fixed-scale base 2, and each pole-counting unit can correspond to one modulation unit group. Each modulation unit group includes a modulation unit F2-1 and a modulation unit G2-2. The modulation unit F2-1 and the modulation unit G2-2 are made of different materials. All the modulation units F2-1 and the modulation unit G2-2 are arranged alternately along the length of the fixed-scale base 2. The modulation unit F2-1 in the modulation unit group can correspond to a set of sensing electrode groups in the pole-counting unit along the length of the fixed-scale base 2. Then the modulation unit G2-2 in the modulation unit group can correspond to the remaining two sets of sensing electrode groups in the same pole-counting unit.

[0039] During measurement, sinusoidal excitation voltage signals U with equal amplitude and same frequency, and a phase difference of 2π / 3, are applied to the three excitation unit groups A1, B2, and C3, respectively. A1 =U m sinωt,U B2 =U msin(ωt+2π / 3), U C3 =U m sin(ωt+4π / 3), (the number of excitation unit groups is multiple, then corresponding to A1, B2, C3, D4...M) N A sinusoidal excitation voltage signal U with equal amplitude and same frequency, phased by 2π / N, is applied to each of the N groups of excitation units. A1 =U m sinωt,U B2 =U m sin(ωt+2π / N×1), U C3 =U m sin(ωt+2π / N×2), U D4 =U m sin(ωt+2π / N×3)……U MN =U m sin(ωt+2π / N×(N-1)), N=3,4,5……。 ) At this time, the excitation electrode 1-1 and the induction electrode 1-2 on the moving scale base 1 form a capacitor structure. If the modulation units between the capacitors are uniform and unchanged, the signals of their excitation unit groups cancel each other out, and the output of the induction unit group E is always zero; when the moving scale base 1 and the fixed scale base 2 are installed parallel and facing each other, the induction unit group E generates a non-zero output signal. When the moving scale base 1 moves linearly relative to the fixed scale base 2 in the length direction, the modulation unit groups uniformly arranged on the fixed scale base 2 cause the induction unit group E to generate an output signal U proportional to the linear displacement. o :

[0040] U o =K e U m sin(ωt+k0x)

[0041] The excitation voltage amplitude U m =5V, frequency f = 40kHz, angular frequency ω = 2πf = 8 × 10 4 π, K e is the electric field coupling coefficient, k0 is the displacement coefficient, and x is the measured displacement value.

[0042] During measurement, in this specific embodiment, such as Figure 3As shown, after the moving scale base moves x relative to the fixed scale base, the signal Uo output by the induction electrode on the stator is acquired by the signal acquisition module. The signal output by the induction electrode is input into the shaping circuit to form a square wave. The square wave signal is input into the FPGA signal processing system and compared with the fixed reference square wave Ur of the same frequency on the same rising edge. The phase difference between the input shaped square wave signal and the reference square wave signal Ur is interpolated and counted by a high-frequency pulse clock. The linear displacement x of the moving scale base 1 relative to the fixed scale base 2 can be obtained by converting the interpolated count value.

[0043] Example 2

[0044] As another embodiment of the present invention, such as Figure 4 As shown in this specific embodiment, the moving scale substrate 1 is provided with multiple counter pole units, each counter pole unit contains three sets of sensing electrodes, and the modulation unit F2-1 on the fixed scale substrate 2 can correspond to two sets of sensing electrodes in the counter pole unit along the length direction of the fixed scale substrate, and the modulation unit G2-2 corresponds to one set of sensing electrodes in the same counter pole unit.

[0045] Example 3

[0046] As another embodiment of the present invention, such as Figure 5 As shown in this specific embodiment, the moving scale substrate 1 is provided with multiple counter pole units, each counter pole unit contains four sets of sensing electrodes, and the modulation unit F2-1 on the fixed scale substrate 2 can correspond to one set of sensing electrodes in the counter pole unit along the length direction of the fixed scale substrate, and the modulation unit G2-2 corresponds to three sets of sensing electrodes in the same counter pole unit.

[0047] Example 4

[0048] As another embodiment of the present invention, such as Figure 6 As shown in this specific embodiment, the moving scale substrate 1 is provided with multiple counter pole units, each counter pole unit contains four sets of sensing electrodes, and the modulation unit F2-1 on the fixed scale substrate 2 can correspond to two sets of sensing electrodes in the counter pole unit along the length direction of the fixed scale substrate, and the modulation unit G2-2 corresponds to two sets of sensing electrodes in the same counter pole unit.

[0049] Example 5

[0050] As another embodiment of the present invention, such as Figure 7 As shown in this specific embodiment, the moving scale substrate 1 is provided with multiple counter pole units, each counter pole unit contains four sets of sensing electrodes, and the modulation unit F2-1 on the fixed scale substrate 2 can correspond to three sets of sensing electrodes in the counter pole unit along the length direction of the fixed scale substrate, and the modulation unit G2-2 corresponds to one set of sensing electrodes in the same counter pole unit.

[0051] Example 6

[0052] As another embodiment of the present invention, such as Figure 8 As shown, in this specific embodiment, the fixed-length base 2 and the modulation unit F2-1 are made of the same material, while the modulation unit G2-2 is made of a different material than the two, and the plane where the modulation unit F2-1 is located and the plane where the modulation unit G2-2 is located are not on the same plane, but the planes where the two are located are parallel.

[0053] Example 7

[0054] As another embodiment of the present invention, such as Figure 9 As shown, in this specific embodiment, the fixed-length base 2 and the modulation unit G2-2 are made of the same material, while the modulation unit F2-1 is made of a different material than the two, and the plane where the modulation unit F2-1 is located and the plane where the modulation unit G2-2 is located are not on the same plane, but the planes where the two are located are parallel.

[0055] Example 8

[0056] As another embodiment of the present invention, such as Figure 10 As shown in this specific embodiment, the fixed-length base 2, the modulation unit F2-1 and the modulation unit G2-2 are made of different materials, and the modulation unit F2-1 and the modulation unit G2-2 are located on the same plane.

[0057] Example 9

[0058] As another embodiment of the present invention, such as Figure 11 As shown, in this specific embodiment, the fixed-length base 2, the modulation unit F2-1 and the modulation unit G2-2 are made of different materials, and the planes on which the modulation unit F2-1 and the modulation unit G2-2 are located are not on the same plane, but the planes on which they are located are parallel.

[0059] Example 10

[0060] As another embodiment of the present invention, such as Figure 12 As shown, in this specific embodiment, the cross-sectional shape of the modulation unit F2-1 is circular.

[0061] Example 11

[0062] As another embodiment of the present invention, such as Figure 13 As shown, in this specific embodiment, the cross-sectional shape of the modulation unit F2-1 is square.

[0063] Example 12

[0064] As another embodiment of the present invention, such as Figure 14 As shown, in this specific embodiment, the cross-sectional shape of the modulation unit F2-1 is elliptical.

[0065] Example 13

[0066] As another embodiment of the present invention, such as Figure 15 As shown, in this specific embodiment, the cross-sectional shape of the modulation unit F2-1 is rhomboid.

[0067] Example 14

[0068] As another embodiment of the present invention, such as Figure 16 As shown, in this specific embodiment, the cross-sectional shape of the modulation unit F2-1 is a double sine shape.

[0069] Example 15

[0070] As another embodiment of the present invention, such as Figure 17 As shown, in this specific embodiment, the cross-sectional shape of the modulation unit F2-1 is oblique cosine.

[0071] Example 16

[0072] As another embodiment of the present invention, such as Figure 18 As shown, in this specific embodiment, the cross-sectional shape of the modulation unit F2-1 is a double cosine shape.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A linear displacement sensor based on electric field self-coupling, comprising a movable scale base and a fixed scale base arranged opposite to and parallel to each other, wherein the opposite sides of the movable scale base and the fixed scale base are parallel to each other and have a gap, characterized in that: Multiple pole-counting units are provided on one side of the moving scale base facing the fixed scale base. Each pole-counting unit includes at least three sets of sensing electrode groups arranged at intervals along the length of the moving scale base. Each set of sensing electrode groups includes an excitation electrode and a sensing electrode arranged at intervals along the length of the moving scale base. The spacing between the excitation electrode and the sensing electrode in each set of sensing electrodes is the same. All excitation electrodes and sensing electrodes are arranged alternately along the length of the moving scale base. When there are multiple counter pole units, all counter pole units are evenly spaced along the length of the moving scale substrate, and multiple sets of sensing electrodes in the counter pole units are evenly spaced along the length of the moving scale substrate. The excitation electrodes located at each position in the counter pole unit along the length of the moving scale substrate are electrically connected to the excitation electrodes at the corresponding positions in the other counter pole units along the length of the moving scale substrate. All sensing electrodes are electrically connected together. On the fixed-scale substrate, on one side facing the movable-scale substrate, there are several modulation unit groups arranged along the length of the fixed-scale substrate. All the pole pairs on the movable-scale substrate can correspond to the same number of adjacent modulation unit groups on the fixed-scale substrate along the length of the fixed-scale substrate, and each pole pair can correspond to one modulation unit group. Each modulation unit group includes a modulation unit F and a modulation unit G. The modulation unit F and the modulation unit G are made of different materials. All the modulation units F and the modulation unit G are arranged alternately along the length of the fixed-scale substrate. The modulation unit F can correspond to at least one set of sensing electrode groups in the pole pair along the length of the fixed-scale substrate.

2. The linear displacement sensor based on electric field self-coupling according to claim 1, characterized in that: The material of the modulation unit F or the modulation unit G is the same as the material of the fixed-length substrate.

3. The linear displacement sensor based on electric field self-coupling according to claim 1, characterized in that: The modulation unit F, the modulation unit G, and the fixed-length substrate are all made of different materials.

4. The linear displacement sensor based on electric field self-coupling according to claim 1, characterized in that: The modulation unit F and the modulation unit G are located on the same plane, or the plane where the modulation unit F is located is parallel to the plane where the modulation unit G is located.

5. The linear displacement sensor based on electric field self-coupling according to claim 1, characterized in that: The cross-sectional shape of the modulation unit F is a centrally rotationally symmetric figure.

6. The linear displacement sensor based on electric field self-coupling according to claim 5, characterized in that: The cross-sectional shape of the modulation unit F is any one of the following: circular, square, elliptical, rhomboid, double sine, oblique cosine, or double cosine.

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