Linear displacement sensor based on electric field self-coupling

Abstract

A linear displacement sensor based on electric field self-coupling, comprising a moving scale base (1) and a fixed scale base (2). One or more paired electrode units are provided on the side surface of the moving scale base (1) facing the fixed scale base (2); each paired electrode unit comprises at least three sensing electrode groups spaced in the length direction of the moving scale base (1); each sensing electrode group comprises one excitation electrode (1-1) and one sensing electrode (1-2) spaced in the length direction of the moving scale base (1). A plurality of modulation unit groups arranged in the length direction of the fixed scale base (2) are provided on the side surface of the fixed scale base (2) facing the moving scale base (1); in the length direction of the fixed scale base (2), all the paired electrode units on the moving scale base (1) can respectively correspond to the same number of adjacent modulation unit groups on the fixed scale base (2); each modulation unit group comprises one modulation unit F(2-1) and one modulation unit G(2-2); the modulation unit F(2-1) can correspond to at least one sensing electrode group in the paired electrode units in the length direction of the fixed scale base (2).

Description

Linear displacement sensor based on electric field self-coupling TECHNICAL FIELD

[0001] The present application relates to the field of measurement sensor technology, in particular to a linear displacement sensor based on electric field self-coupling. BACKGROUND

[0002] With the rapid development of industrial technology, human beings have higher and higher requirements for displacement precision measurement technology. As one of the three foundations of modern information technology, sensor technology is closely related to the working performance and measurement results. Time grating displacement sensor is a self-developed and produced displacement sensor, which realizes the measurement of time quantity to space quantity.

[0003] A kind of electric field type time grating linear displacement sensor based on single row multilayer structure (publication number CN103822571A) has been disclosed in prior art, which uses high-frequency clock pulse as measurement reference, and uses the alternating electric field constructed by flat plate capacitor to directly couple out the electric traveling wave signal required for measurement, so that high-precision displacement measurement in a large range can be realized. However, the moving scale and the fixed scale of the sensor need to be respectively led, and as the range of the fixed scale of the sensor increases, the internal resistance of the fixed scale will become larger and larger due to the lead, which limits the measurement range of the sensor, and the installation of signal output line is more troublesome, which reduces the reliability of the sensor.

[0004] SUMMARY

[0005] In view of the above problems of the prior art, the technical problem to be solved by the present application is to provide a linear displacement sensor based on electric field self-coupling, which has a simple and reliable structure, can realize passive sensing of the fixed scale base body, and solves the problem of excessive internal resistance caused by the lead of the fixed scale base body, thereby limiting the measurement range.

[0006] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0007] A linear displacement sensor based on electric field self-coupling, comprising a moving scale base body and a fixed scale base body arranged oppositely and in parallel, the opposite sides of the moving scale base body and the fixed scale base body are parallel to each other with a gap, one or more antipodal units are arranged on the side surface of the moving scale base body facing the direction of the fixed scale base body, the antipodal unit comprises at least three groups of sensing electrode groups arranged at intervals along the length direction of the moving scale base body, each group of sensing electrode groups comprises one excitation electrode and one induction electrode arranged at intervals along the length direction of the moving scale base body, the distance between the excitation electrode and the induction electrode in each group of sensing electrode groups is the same, and all the excitation electrodes and the induction electrodes are arranged at intervals along the length direction of the moving scale base body.

[0008] When there is only one counter electrode unit, the multiple groups of sensing electrode groups in the counter electrode unit are arranged uniformly along the length direction of the ruler base body; when there are multiple counter electrode units, all the counter electrode units are arranged uniformly along the length direction of the ruler base body, and the multiple groups of sensing electrode groups in the counter electrode units are arranged uniformly along the length direction of the ruler base body, the excitation electrodes at each arrangement sequence position along the length direction of the ruler base body in the counter electrode unit are electrically connected together with the excitation electrodes at the corresponding arrangement sequence positions along the length direction of the ruler base body in the remaining counter electrode units, and all the sensing electrodes are electrically connected together;

[0009] A plurality of modulation unit groups are arranged along the length direction of the ruler base body on one side surface of the ruler base body and face the direction in which the ruler base body is located, all the counter electrode units on the ruler base body can correspond to the same number of adjacent modulation unit groups on the ruler base body along the length direction of the ruler base body, and each counter electrode unit can correspond to one modulation unit group, each modulation unit group comprises one modulation unit F and one modulation unit G, the modulation unit F and the modulation unit G are made of different materials, all the modulation unit F and the modulation unit G are arranged alternately along the length direction of the ruler base body, and the modulation unit F can correspond to at least one group of sensing electrode groups in the counter electrode unit along the length direction of the ruler base body.

[0010] As an optimization, the material of the modulation unit F or the modulation unit G is consistent with the material of the ruler base body.

[0011] As an optimization, the modulation unit F, the modulation unit G and the ruler base body are made of different materials.

[0012] As an optimization, the modulation unit F and the modulation unit G are located on the same plane, or the plane on which the modulation unit F is located is parallel to the plane on which the modulation unit G is located.

[0013] As an optimization, the cross-sectional shape of the modulation unit F is a central rotationally symmetric figure.

[0014] As an optimization, the cross-sectional shape of the modulation unit F is any one of a circle, a square, an ellipse, a diamond, a double sine shape, a slant cosine shape or a double cosine shape.

[0015] Compared with the prior art, the present application has the following beneficial effects: the signal input and output signals of the sensor in the present application are located on the ruler base body, passive sensing of the ruler base body can be realized, and the measurement range of the ruler base body can be increased at will; the material of the modulation unit on the sensor ruler base body can be metal or non-metal, which is not limited by manufacturing materials and processes, and the detectable range of the sensor is wider; the signal strength output by the sensing unit on the ruler base body is not restricted by the number of sensing electrodes, the signal transmission efficiency is higher, and the present application has a wider application scenario and applicability. BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 is a schematic diagram of a three-dimensional structure of embodiment 1 of the present application;

[0017] Fig. 2 is a schematic diagram of the corresponding structure of a pole cell and modulation unit F and modulation unit G in embodiment 1 of the present application;

[0018] Fig. 3 is a schematic diagram of the displacement signal solving flow in embodiment 1 of the present application;

[0019] Fig. 4 is a schematic diagram of the corresponding structure of a pole cell and modulation unit F and modulation unit G in embodiment 2 of the present application;

[0020] Fig. 5 is a schematic diagram of the corresponding structure of a pole cell and modulation unit F and modulation unit G in embodiment 3 of the present application;

[0021] Fig. 6 is a schematic diagram of the corresponding structure of a pole cell and modulation unit F and modulation unit G in embodiment 4 of the present application;

[0022] Fig. 7 is a schematic diagram of the corresponding structure of a pole cell and modulation unit F and modulation unit G in embodiment 5 of the present application;

[0023] Fig. 8 is a schematic diagram of the three-dimensional structure of the modulation unit group on the sizing substrate in embodiment 6 of the present application;

[0024] Fig. 9 is a schematic diagram of the three-dimensional structure of the modulation unit group on the sizing substrate in embodiment 7 of the present application;

[0025] Fig. 10 is a schematic diagram of the three-dimensional structure of the modulation unit group on the sizing substrate in embodiment 8 of the present application;

[0026] Fig. 11 is a schematic diagram of the three-dimensional structure of the modulation unit group on the sizing substrate in embodiment 9 of the present application;

[0027] Fig. 12 is a top view of the sizing substrate in embodiment 10 of the present application;

[0028] Fig. 13 is a top view of the sizing substrate in embodiment 11 of the present application;

[0029] Fig. 14 is a top view of the sizing substrate in embodiment 12 of the present application;

[0030] Fig. 15 is a top view of the sizing substrate in embodiment 13 of the present application;

[0031] Fig. 16 is a top view of the sizing substrate in embodiment 14 of the present application;

[0032] Fig. 17 is a top view of the sizing substrate in embodiment 15 of the present application;

[0033] Fig. 18 is a top view of the sizing substrate in embodiment 16 of the present application. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0035] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, and are merely for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical" and the like do not mean that the components must be absolutely horizontal or vertical, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined. In the description of the present application, it should also be noted that unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] Embodiment 1

[0037] As shown in FIG. 1 and FIG. 2, the linear displacement sensor based on electric field self-coupling in the present embodiment comprises a moving scale base 1 and a fixed scale base 2 arranged oppositely and in parallel, the opposite sides of the moving scale base 1 and the fixed scale base 2 are parallel to each other with a gap, two antipodal units are arranged on the side of the moving scale base 1 facing the direction of the fixed scale base 2, the antipodal unit comprises three groups of sensing electrode groups arranged along the length direction of the moving scale base 1, each group of sensing electrode groups comprises an excitation electrode 1-1 and an induction electrode 1-2 arranged along the length direction of the moving scale base 1, the distance between the excitation electrode 1-1 and the induction electrode 1-2 in each group of sensing electrode groups is the same, and all the excitation electrodes 1-1 and the induction electrodes 1-2 are staggered and arranged along the length direction of the moving scale base;

[0038] The two antipodal units are arranged along the length direction of the moving scale base 1 (if the number of antipodal units is more than three, the antipodal units are uniformly arranged along the length direction of the moving scale base 1), and the multiple groups of sensing electrode groups in the antipodal unit are uniformly arranged along the length direction of the moving scale base 1, the excitation electrodes 1-1 at each arrangement sequence position along the length direction of the moving scale base 1 in the antipodal unit are electrically connected together with the excitation electrodes 1-1 at the corresponding arrangement sequence position along the length direction of the moving scale base 1 in the remaining antipodal units, and all the induction electrodes 1-2 are electrically connected together; that is, the excitation electrodes 1-1 at the first arrangement sequence position in the antipodal unit are electrically connected together with all the excitation electrodes 1-1 at the first arrangement sequence position in the remaining antipodal units to form an excitation unit group A1, the excitation electrodes 1-1 at the third arrangement sequence position in the antipodal unit are electrically connected together with all the excitation electrodes 1-1 at the third arrangement sequence position in the remaining antipodal units to form an excitation unit group B2, the excitation electrodes 1-1 at the fifth arrangement sequence position in the antipodal unit are electrically connected together with all the excitation electrodes 1-1 at the fifth arrangement sequence position in the remaining antipodal units to form an excitation unit group C3 (if the antipodal unit comprises multiple groups of sensing electrode groups, the excitation electrodes 1-1 at the Nth arrangement sequence position in the antipodal unit are electrically connected together with all the excitation electrodes 1-1 at the Nth arrangement sequence position in the remaining antipodal units to form an excitation unit group M N ), and then all the induction electrodes 1-2 in the antipodal units are electrically connected together to form an induction unit group E;

[0039] A plurality of modulation unit groups are arranged on the side of the fixed ruler base 2 facing the direction of the moving ruler base 1, and along the length direction of the fixed ruler base 2. All the opposite-pole units on the moving ruler base 1 can correspond to the same number of adjacent modulation unit groups on the fixed ruler base 2 along the length direction of the fixed ruler base 2, and each opposite-pole unit can correspond to one modulation unit group. Each modulation unit group includes one modulation unit F2-1 and one modulation unit G2-2, which are made of different materials. All the modulation unit F2-1 and the modulation unit G2-2 are staggered along the length direction of the fixed ruler base 2. The modulation unit F2-1 in the modulation unit group can correspond to a group of sensing electrodes in the opposite-pole unit along the length direction of the fixed ruler base 2, and then the modulation unit G2-2 in the modulation unit group can correspond to the remaining two groups of sensing electrodes in the same opposite-pole unit.

[0040] During measurement, equal-amplitude and same-frequency sinusoidal excitation voltage signals U A1 =U m sinωt, U B2 =U m sin(ωt+2π / 3), U C3 =U m sin(ωt+4π / 3) are respectively applied on the A1, B2, C3 three groups of excitation unit groups with a phase difference of 2π / 3. N If the number of excitation unit groups is multiple, then equal-amplitude and same-frequency sinusoidal excitation voltage signals U 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)) are respectively applied on the A1, B2, C3, D4 …… M o N groups of excitation unit groups with a phase difference of 2π / N. At this time, the excitation electrode 1-1 and the sensing electrode 1-2 on the moving ruler base 1 form a capacitive structure. If the modulation units between the capacitors are uniform and unchanged, the excitation unit group signals cancel each other out, and the sensing unit group E always outputs zero. When the moving ruler base 1 is installed in parallel with the fixed ruler base 2, the sensing unit group E generates a non-zero output signal. When the moving ruler base 1 moves linearly relative to the length direction of the fixed ruler base 2, the uniformly arranged modulation unit groups on the fixed ruler base 2 make the sensing unit group E generate an output signal Uo = K e U m sin(ωt+k0x)

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

[0042] In the embodiment, when measuring, as shown in FIG. 3, after the moving scale base moves x relative to the fixed scale base, the signal acquisition module acquires the signal Uo output by the inductive electrode on the stator, inputs the signal output by the inductive electrode into a shaping circuit to form a square wave, inputs the square wave signal into the FPGA signal processing system to perform phase comparison processing with the same rising edge of the fixed reference square wave Ur of the same frequency, performs interpolation counting on the phase difference between the input shaped square wave signal and the reference square wave signal Ur through a high-frequency pulse clock, and converts the interpolated counting value to obtain the linear displacement x of the moving scale base 1 relative to the fixed scale base 2.

[0043] Embodiment 2

[0044] As another embodiment of the present application, as shown in FIG. 4, in the embodiment, the moving scale base 1 is provided with a plurality of antipodal units, each of which contains three groups of sensing electrode groups, and the modulation unit F2-1 on the fixed scale base 2 can correspond to two groups of sensing electrode groups in the antipodal unit along the length direction of the fixed scale base, and the modulation unit G2-2 corresponds to one group of sensing electrode groups in the same antipodal unit.

[0045] Embodiment 3

[0046] As another embodiment of the present application, as shown in FIG. 5, in the embodiment, the moving scale base 1 is provided with a plurality of antipodal units, each of which contains four groups of sensing electrode groups, and the modulation unit F2-1 on the fixed scale base 2 can correspond to one group of sensing electrode groups in the antipodal unit along the length direction of the fixed scale base, and the modulation unit G2-2 corresponds to three groups of sensing electrode groups in the same antipodal unit.

[0047] Embodiment 4

[0048] As another embodiment of the present application, as shown in FIG. 6, in the embodiment, the moving scale base 1 is provided with a plurality of antipodal units, each of which contains four groups of sensing electrode groups, and the modulation unit F2-1 on the fixed scale base 2 can correspond to two groups of sensing electrode groups in the antipodal unit along the length direction of the fixed scale base, and the modulation unit G2-2 corresponds to two groups of sensing electrode groups in the same antipodal unit.

[0049] Embodiment 5

[0050] As another embodiment of the present application, as shown in Fig. 7, in the present embodiment, a plurality of antipodal units are provided on the moving ruler base 1, each of which contains four groups of sensing electrode groups, and the modulation unit F2-1 on the fixed ruler base 2 is capable of corresponding to three groups of sensing electrode groups in the antipodal unit along the length direction of the fixed ruler base, and the modulation unit G2-2 corresponds to one group of sensing electrode groups in the same antipodal unit.

[0051] Embodiment 6

[0052] As another embodiment of the present application, as shown in Fig. 8, in the present embodiment, the fixed ruler base 2 and the modulation unit F2-1 are made of the same material, and the modulation unit G2-2 is different from the materials of the two, and the plane on which the modulation unit F2-1 is located and the plane on which the modulation unit G2-2 is located are not in the same plane, but the planes on which the two are located are parallel.

[0053] Embodiment 7

[0054] As another embodiment of the present application, as shown in Fig. 9, in the present embodiment, the fixed ruler base 2 and the modulation unit G2-2 are made of the same material, and the modulation unit F2-1 is different from the materials of the two, and the plane on which the modulation unit F2-1 is located and the plane on which the modulation unit G2-2 is located are not in the same plane, but the planes on which the two are located are parallel.

[0055] Embodiment 8

[0056] As another embodiment of the present application, as shown in Fig. 10, in the present embodiment, the fixed ruler base 2, the modulation unit F2-1 and the modulation unit G2-2 are made of different materials respectively, and the modulation unit F2-1 and the modulation unit G2-2 are located on the same plane.

[0057] Embodiment 9

[0058] As another embodiment of the present application, as shown in Fig. 11, in the present embodiment, the fixed ruler base 2, the modulation unit F2-1 and the modulation unit G2-2 are made of different materials respectively, and the plane on which the modulation unit F2-1 is located and the plane on which the modulation unit G2-2 are not in the same plane, but the planes on which the two are located are parallel.

[0059] Embodiment 10

[0060] As another embodiment of the present application, as shown in Fig. 12, in the present embodiment, the cross-sectional shape of the modulation unit F2-1 is circular.

[0061] Embodiment 11

[0062] As another embodiment of the present application, as shown in Fig. 13, in the present embodiment, the cross-sectional shape of the modulation unit F2-1 is square.

[0063] Example 12

[0064] As another embodiment of the present application, as shown in Fig. 14, in the present embodiment, the cross-sectional shape of the modulation unit F2-1 is elliptical.

[0065] Example 13

[0066] As another embodiment of the present application, as shown in Fig. 15, in the present embodiment, the cross-sectional shape of the modulation unit F2-1 is diamond.

[0067] Example 14

[0068] As another embodiment of the present application, as shown in Fig. 16, in the present embodiment, the cross-sectional shape of the modulation unit F2-1 is double-sine.

[0069] Example 15

[0070] As another embodiment of the present application, as shown in Fig. 17, in the present embodiment, the cross-sectional shape of the modulation unit F2-1 is oblique-cosine.

[0071] Example 16

[0072] As another embodiment of the present application, as shown in Fig. 18, in the present embodiment, the cross-sectional shape of the modulation unit F2-1 is double-cosine.

[0073] Finally, it should be noted that the above examples are merely used to illustrate the technical solutions of the present application but not to limit the technical solutions. Those of ordinary skill in the art should understand that modifications or equivalent replacements to the technical solutions of the present application without departing from the spirit and scope of the present application should be included in the scope of the claims of the present application.

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: One or more counter pole units are provided on the side of the moving scale base facing the fixed scale base. The counter pole unit includes at least three sets of sensing electrode groups arranged at intervals along the length direction 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 direction 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 direction of the moving scale base. 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. 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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