Linear Displacement Sensor Based on Electric Field Self-Coupling

Abstract

A linear displacement sensor based on electric field self-coupling, comprising a movable ruler base 1 and a fixed ruler base 2. The side of the movable ruler base 1 facing the fixed ruler base 2 has o

Description

[0001] This disclosure relates to the technical field of measurement sensing, and in 5 particular, to a linear displacement sensor based on electric field self-coupling. BACKGROUND

[0002] With the rapid development of industrial technologies, human beings have increasingly higher requirements for precise displacement measurement technology. Sensor technology is as one of the three foundations of modem information technologies, 10 and its performance is closely related to measurement results. Atime grating displacement sensor is a self-developed displacement sensor, which implements measurement of time quantity relative to space quantity.

[0003] A patent has been published in the prior art, which is an electric field type time grating linear displacement sensor based on a single-row multilayered structure 15 (publication number of CN103822571A). The sensor takes a high-frequency clock pulse as a measurement reference, and adopts an alternating electric field constructed by a plate capacitor to directly couple an electric traveling wave signal needed for measurement, so that high-precision displacement measurement in a large range can be implemented. However, a moved ruler and a fixed ruler of the sensor need to be led separately. With the 20 increase of a range of the fixed ruler of the sensor, a lead on the fixed ruler can cause its internal resistance to increase continuously, which limits a measuring range of the sensor, and leads to the decrease of the reliability of the sensor due to relatively troublesome installation of a signal output line. SUMMARY 25

[0004] For the above deficiencies in the prior art, a technical problem to be solved by this disclosure is how to provide a linear displacement sensor based on electric field selfcoupling, which has a simple and reliable structure, and can implement passive sensing of a fixed ruler substrate and solve the problem of excessive internal resistance caused by a lead wire of the fixed ruler substrate, thus limiting a measuring range. 10 15

[0005] To solve the above technical problems, the following technical solutions are used in this disclosure. CXI CXI CXI 20 25 30

[0006] A linear displacement sensor based on electric field self-coupling includes a moved ruler substrate and a fixed ruler substrate that are oppositely and parallelly arranged. A side surface of the moved ruler substrate and an opposite side of the fixed ruler substrate are parallel to each other with a gap, and a plurality of pole-opposing units are arranged on a side surface of the moved ruler substrate facing a direction of the fixed ruler substrate. The pole-opposing unit includes at least three sensing electrode groups arranged at intervals along a length direction of the moved ruler substrate, and each of the sensing electrode groups includes an excitation electrode and an induction electrode that are arranged at intervals along the length direction of the moved ruler substrate. A distance between the excitation electrode and the induction electrode in each sensing electrode group is identical, and all the excitation electrodes and induction electrodes are arranged at equal intervals along the length direction of the moved ruler substrate.

[0007] all the pole-opposing units are evenly spaced along the length direction of the moved ruler substrate, and the plurality of sensing electrode groups in the pole-opposing units are evenly spaced along the length direction of the moved ruler substrate. The excitation electrodes located at arrangement sequence positions along the length direction of the moved ruler substrate in the pole-opposing unit are respectively electrically connected to the excitation electrodes located at corresponding arrangement sequence positions along the length direction of the moved ruler substrate in the other poleopposing units, and all the induction electrodes are electrically connected together.

[0008] A plurality of modulation unit groups arranged along a length direction of the fixed ruler substrate are arranged on a side surface of the fixed ruler substrate facing a direction of the moved ruler substrate. All the pole-opposing units on the moved ruler substrate can respectively correspond to a same number of adjacent modulation unit groups on the fixed ruler substrate along the length direction of the fixed ruler substrate, and each pole-opposing unit can correspond to a 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 units G are alternately arranged along the length direction of the fixed ruler substrate, and the modulation unit F can correspond to at least one sensing electrode group in the pole-opposing unit along the length direction of the fixed ruler substrate.

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

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

[0011] As an optimization, the modulation unit F and the modulation unit G are located on a same plane, or a plane where the modulation unit F is located is parallel to a plane where the modulation unit G is located. 10 15 CXI CXI CXI 20

[0012] As an optimization, a cross-section shape of the modulation unit F is a central rotation symmetric figure.

[0013] As an optimization, the cross-section shape of the modulation unit F is any one of a circle, a square, an ellipse, a rhombus, a hyperbolic sine shape, an oblique cosine shape, or a hyperbolic cosine shape.

[0014] Compared with the prior art, this disclosure has the following beneficial effects: signal input and output signals of the sensor in this disclosure are all located on the moved ruler substrate, so that passive sensing of the moved ruler substrate can be implemented, and a measuring range of the fixed ruler substrate can be increased optionally; the modulation unit on the fixed ruler substrate of the sensor may be made of metal or nonmetal, which is not limited by manufacturing materials and processes, and the sensor has a wider detection range; and the intensity of a signal output by a sensing unit on the moved ruler substrate is not restricted by a number of sensing electrodes, so that the signal transmission efficiency is higher, and there are wider application scenarios and applicability in this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a schematic diagram of a three-dimensional structure in Embodiment 1 of this disclosure; 25

[0016] FIG. 2 is a schematic diagram of a corresponding structure between a pole opposing unit and a modulation unit F and a modulation unit G in Embodiment 1 of this disclosure;

[0017] FIG. 3 is a schematic flow chart of displacement signal calculation in Embodiment 1 of this disclosure; 30

[0018] FIG. 4 is a schematic diagram of a corresponding structure between a pole opposing unit and a modulation unit F and a modulation unit G in Embodiment 2 of this disclosure;

[0019] FIG. 5 is a schematic diagram of a corresponding structure between a poleopposing unit and a modulation unit F and a modulation unit G in Embodiment 3 of this disclosure;

[0020] FIG. 6 is a schematic diagram of a corresponding structure between a pole-5 opposing unit and a modulation unit F and a modulation unit G in Embodiment 4 of this disclosure;

[0021] FIG. 7 is a schematic diagram of a corresponding structure between a poleopposing unit and a modulation unit F and a modulation unit G in Embodiment 5 of this disclosure; 10 15

[0022] FIG. 8 is a schematic diagram of a three-dimensional structure of a modulation unit group on a fixed ruler substrate in Embodiment 6 of this disclosure;

[0023] FIG. 9 is a schematic diagram of a three-dimensional structure of a modulation unit group on a fixed ruler substrate in Embodiment 7 of this disclosure;

[0024] FIG. 10 is a schematic diagram of a three-dimensional structure of a modulation unit group on a fixed ruler substrate in Embodiment 8 of this disclosure; CXI

[0025] FIG. 11 is a schematic diagram of a three-dimensional structure of a modulation CXI unit group on a fixed ruler substrate in Embodiment 9 of this disclosure;

[0026] FIG. 12 is top view of fixed ruler substrate in Embodiment 10 of this disclosure; CXI 20

[0027] FIG. 13 is top view of fixed ruler substrate in Embodiment 11 of this disclosure;

[0028] FIG. 14 is top view of fixed ruler substrate in Embodiment 12 of this disclosure; 25

[0029] FIG. 15 is top view of fixed ruler substrate in Embodiment 13 of this disclosure;

[0030] FIG. 16 is top view of fixed ruler substrate in Embodiment 14 of this disclosure;

[0031] FIG. 17 is top view of fixed ruler substrate in Embodiment 15 of this disclosure; and 30

[0032] FIG. 18 is top view of fixed ruler substrate in Embodiment 16 of this disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS 10 15 25 30

[0033] To make the purpose, technical solutions, and advantages of the embodiments of this disclosure clearer, the following clearly and completely describes the technical solutions of the embodiments of this disclosure with reference to the accompanying drawings in the embodiments of this disclosure. Apparently, the embodiments described are only a part rather than all of the embodiments of this disclosure. Generally, assemblies, of the embodiments of this disclosure, described and illustrated in the accompanying drawings herein may be arranged and designed in a variety of different configurations. Therefore, the detailed description of the embodiments of this disclosure provided in the accompanying drawings is not intended to limit the claimed protection scope of this disclosure, but only to represent selected embodiments of this disclosure. Based on the embodiments in this disclosure, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope of protection of this disclosure.

[0034] It should be noted that similar reference numerals and letters refer to similar items in the following accompanying drawings, and therefore, once an item is defined in one accompanying drawing, it is not necessary to further define and explain the item in the subsequent accompanying drawings. In the description of this disclosure, it should be noted that the orientations or positional relationships indicated by the terms “center”, “up”, “down”, “left”, “right”, “vertical”, “horizontal”, “inside”, “outside”, etc. are in accordance with those shown in the accompanying drawings, or refer to orientations or positional relationships in which a product of this disclosure is typically placed when in use, and are intended only for the convenience of describing this disclosure and simplifying the description rather than for indicating or implying that the referred device or element must be provided with a particular orientation or constructed and operated in a particular orientation; therefore, they should not be construed as limiting this disclosure. Furthermore, the terms “first”, “second”, “third” are merely used for the purpose of distinguishing description and should not be construed as indication or implication of relative importance. In addition, terms such as “horizontal” and “vertical” do not imply that the component is required to be absolutely horizontal or suspended, but may be slightly tilted. “Horizontal” only refers to its direction being more horizontal relative to “vertical”, and does not necessarily mean that the structure must be absolutely horizontal, but may be slightly tilted. In the description of this disclosure, it should be further noted 10 15 CXI CXI CXI 20 25 30 that, unless otherwise explicitly provided and limited, the terms “arranged”, “mounted”, “connected”, and “connection” should be understood in a broad sense, e.g., it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium; and it may be a connection between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this disclosure may be understood based on specific circumstances.

[0035] Embodiment 1

[0036] As shown in FIG. 1 and FIG. 2, a linear displacement sensor based on electric field self-coupling in a specific implementation includes a moved ruler substrate 1 and a fixed ruler substrate 2 that are oppositely and parallelly arranged. A side surface of the moved ruler substrate 1 and an opposite side of the fixed ruler substrate 2 are parallel to each other with a gap, and two pole-opposing units are arranged on a side surface of the moved ruler substrate 1 facing a direction of the fixed ruler substrate 2. The pole-opposing unit includes three sensing electrode groups arranged at intervals along a length direction of the moved ruler substrate 1, and each of the sensing electrode groups includes an excitation electrode 1-1 and an induction electrode 1-2 that are arranged at intervals along the length direction of the moved ruler substrate 1. A distance between the excitation electrode 1-1 and the induction electrode 1-2 in each sensing electrode group is identical, and all the excitation electrodes 1-1 and induction electrodes 1-2 are arranged at equal intervals along the length direction of the moved ruler substrate.

[0037] The two pole-opposing units are arranged at intervals along the length direction of the moved ruler substrate 1 (if there are more than three pole-opposing units, these pole-opposing units are evenly arranged at intervals along the length direction of the moved ruler substrate 1), and the plurality of sensing electrode groups in the poleopposing unit are evenly arranged at intervals along the length direction of the moved ruler substrate 1. The excitation electrodes 1-1 located at arrangement sequence positions along the length direction of the moved ruler substrate 1 in the pole-opposing unit are respectively electrically connected to the excitation electrodes 1-1 located at corresponding arrangement sequence positions along the length direction of the moved ruler substrate 1 in the other pole-opposing units, and all the induction electrodes 1-2 are electrically connected together. That is, an excitation electrode 1-1 located at a first arrangement sequence in the pole-opposing unit is respectively electrically connected to all the excitation electrodes 1-1 at a first arrangement sequence in the other pole-opposing 10 15 CXI CXI CXI 20 25 30 unit to form an excitation unit group Ai, an excitation electrode 1-1 located at a third arrangement sequence in the pole-opposing unit is respectively electrically connected to all the excitation electrodes 1-1 at a third arrangement sequence in the other poleopposing unit to form an excitation unit group B2, an excitation electrode 1-1 located at a fifth arrangement sequence in the pole-opposing unit is respectively electrically connected to all the excitation electrodes 1-1 at a fifth arrangement sequence in the other pole-opposing unit to form an excitation unit group C3 (if the pole-opposing unit includes a plurality of sensing electrode groups, by analogy, an excitation electrode 1-1 located at an Nth arrangement sequence in the pole-opposing unit is respectively electrically connected to all the excitation electrodes 1-1 at an Nt h arrangement sequence in the other pole-opposing unit to form an excitation unit group Mn), and then, the induction electrodes 1-2 in all the pole-opposing units are electrically connected to form an induction unit group E.

[0038] A plurality of modulation unit groups arranged along a length direction of the fixed ruler substrate 2 are arranged on a side surface of the fixed ruler substrate 2 facing a direction of the moved ruler substrate 1, all the pole-opposing units on the moved ruler substrate 1 can respectively correspond to a same number of adjacent modulation unit groups on the fixed ruler substrate 2 along the length direction of the fixed ruler substrate 2, and each pole-opposing unit can correspond to a 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 units G2-2 are alternately arranged along the length direction of the fixed ruler substrate 2, and the modulation unit F2-1 in the modulation unit group can correspond to a sensing electrode group in the pole-opposing unit along the length direction of the fixed ruler substrate 2, so the modulation unit G2-2 in the modulation unit group can correspond to remaining two sensing electrode groups in the same pole-opposing unit.

[0039] During measurement, sinusoidal excitation voltage signals of K4i=f7msinc9t, f / B2=t / msin(c9t+27t / 3), and Uc3=Umsm(cot+47i / 3) with equal amplitude and frequency and a phase difference of 2k / 3 are respectively applied to the three excitation unit groups of Ai, B2, and C3 (there are a plurality of excitation unit groups, so corresponding sinusoidal excitation voltage signals of K4i=f7msinc9t, f / B2=t / msin(c9t+27t / Axl), f / c3=t / msin(c9t+27t / Ax2), tt?4=f / msin(c9t+27t / Ax3), ..., and UMN=Umsin((ot+2n / N*(N-Vj) with equal amplitude and frequency and a phase difference of 2idN are respectively applied to TV excitation unit groups ofAi,B2, C3, D4, ..., and A / v, #=3,4,5, ...), and in this case, the excitation electrode 1-1 and the induction electrode 1-2 on the moved ruler substrate 1 form a capacitor structure. If the modulation units between capacitors are uniform, signals of the excitation unit groups cancel each other, and an output of the 5 induction unit group E is always zero. When the moved ruler substrate 1 and the fixed ruler substrate 2 are installed in parallel, the induction unit group E generates a non-zero output signal. When the moved ruler substrate 1 moves linearly relative to the length direction of the fixed ruler substrate 2, the modulation unit groups evenly distributed on the fixed ruler substrate 2 cause the induction unit group E generate an output signal Uo 10 proportional to a linear displacement: Uo=KeUmsm(cot+kox)

[0040] where an excitation voltage amplitude is Um=5N, a frequency is / =40KHz, an angular frequency is m=27t^8x 1047t, Ke is an electric field coupling coefficient, ko is a displacement coefficient, and visa measured displacement value. 15

[0041] During measurement, in this specific implementation, as shown in FIG. 3, after the moved ruler substrate moves x relative to the fixed ruler substrate, a signal Uo output by the induction electrode on a stator is collected by a signal collection module, the signal output by the induction electrode is input into a shaping circuit to form a square wave, a square wave signal is input into an FPGA signal processing system to perform phase 20 comparison processing of a same rising edge together with a fixed reference square wave Ur with a same frequency, a phase difference between the input shaped square wave signal and the reference square wave signal Ur is interpolated and counted through a high-frequency pulse clock, and a linear displacement x of the moved ruler substrate 1 relative to the fixed ruler substrate 2 may be obtained by converting the interpolated count value. 25

[0042] Embodiment 2

[0043] As another implementation of this disclosure, as shown in FIG. 4, in this specific implementation, a plurality of pole-opposing units are arranged on the moved ruler substrate 1, each pole-opposing unit includes three sensing electrode groups, a modulation unit F2-1 in the fixed ruler substrate 2 can correspond to two sensing electrode 30 groups in the pole-opposing unit along a length direction of the fixed ruler substrate, and a modulation unit G2-2 corresponds to a sensing electrode group in the same poleopposing unit.

[0044] Embodiment 3

[0045] As another implementation of this disclosure, as shown in FIG. 5, in this specific implementation, a plurality of pole-opposing units are arranged on the moved ruler substrate 1, each pole-opposing unit includes four sensing electrode groups, a modulation unit F2-1 in the fixed ruler substrate 2 can correspond to a sensing electrode group in the pole-opposing unit along a length direction of the fixed ruler substrate, and a modulation 5 unit G2-2 corresponds to three sensing electrode groups in the same pole-opposing unit. 10 15 CXI CXI CXI 20

[0046] Embodiment 4

[0047] As another implementation of this disclosure, as shown in FIG. 6, in this specific implementation, a plurality of pole-opposing units are arranged on the moved ruler substrate 1, each pole-opposing unit includes four sensing electrode groups, a modulation unit F2-1 in the fixed ruler substrate 2 can correspond to two sensing electrode groups in the pole-opposing unit along a length direction of the fixed ruler substrate, and a modulation unit G2-2 corresponds to two sensing electrode groups in the same poleopposing unit.

[0048] Embodiment 5

[0049] As another implementation of this disclosure, as shown in FIG. 7, in this specific implementation, a plurality of pole-opposing units are arranged on the moved ruler substrate 1, each pole-opposing unit includes four sensing electrode groups, a modulation unit F2-1 in the fixed ruler substrate 2 can correspond to three sensing electrode groups in the pole-opposing unit along a length direction of the fixed ruler substrate, and a modulation unit G2-2 corresponds to a sensing electrode group in the same pole-opposing unit.

[0050] Embodiment 6

[0051] As another implementation of this disclosure, as shown in FIG. 8, in this specific implementation, the fixed ruler substrate 2 and the modulation unit F2-1 are made of a 25 same material, while the modulation unit G2-2 is made of a different material, and a plane where the modulation unit F2-1 is located and a plane where the modulation unit G2-2 is located are not on a same plane, but are parallel to each other.

[0052] Embodiment 7

[0053] As another implementation of this disclosure, as shown in FIG. 9, in this specific 30 implementation, the fixed ruler substrate 2 and the modulation unit G2-2 are made of a same material, while the modulation unit F2-1 is made of a different material, and a plane where the modulation unit F2-1 is located and a plane where the modulation unit G2-2 is located are not on a same plane, but are parallel to each other.

[0054] Embodiment 8

[0055] As another implementation of this disclosure, as shown in FIG. 10, in this specific implementation, the fixed ruler substrate 2, the modulation unit F2-1, and the modulation unit G2-2 are respectively made of different materials, and the modulation unit F2-1 and the modulation unit G2-2 are located on a same plane. 5

[0056] Embodiment 9

[0057] As another implementation of this disclosure, as shown in FIG. 11, in this specific implementation, the fixed ruler substrate 2, the modulation unit F2-1, and the modulation unit G2-2 are respectively made of different materials, and a plane where the modulation unit F2-1 is located and a plane where the modulation unit G2-2 is located 10 are not on a same plane, but are parallel to each other.

[0058] Embodiment 10

[0059] As another implementation of this disclosure, as shown in FIG. 12, in this specific implementation, a cross-section shape of the modulation unit F2-1 is a circle.

[0060] Embodiment 11 15

[0061] As another implementation of this disclosure, as shown in FIG. 13, in this CM specific implementation, a cross-section shape of the modulation unit F2-1 is a square.

[0062] Embodiment 12

[0063] As another implementation of this disclosure, as shown in FIG. 14, in this specific implementation, a cross-section shape of the modulation unit F2-1 is an ellipse. £yj 20

[0064] Embodiment 13

[0065] As another implementation of this disclosure, as shown in FIG. 15, in this specific implementation, a cross-section shape of the modulation unit F2-1 is a rhombus.

[0066] Embodiment 14

[0067] As another implementation of this disclosure, as shown in FIG. 16, in this 25 specific implementation, a cross-section shape of the modulation unit F2-1 is a hyperbolic sine shape.

[0068] Embodiment 15

[0069] As another implementation of this disclosure, as shown in FIG. 17, in this specific implementation, a cross-section shape of the modulation unit F2-1 is an oblique 30 cosine shape.

[0070] Embodiment 16

[0071] As another implementation of this disclosure, as shown in FIG. 18, in this specific implementation, a cross-section shape of the modulation unit F2-1 is a hyperbolic cosine shape.

[0072] Finally, it should be noted that the foregoing embodiments are merely intended to describe the technical solutions of this disclosure rather than limiting thereto. A person of ordinary skill in the art should understand that those modifications or equivalent replacements made to the technical solutions of this disclosure, without departing from 5 the spirit and scope of the technical solutions, shall fall within the scope of the claims of this disclosure. 29 12 25

Claims

1. A linear displacement sensor based on electric field self-coupling comprising a moved ruler substrate and a fixed ruler substrate that are oppositely and parallelly arranged, a side surface of the moved ruler substrate and an opposite side of the fixed 5 ruler substrate parallel to each other with a gap, wherein a plurality of pole-opposing units are arranged on a side surface of the moved ruler substrate facing a direction of the fixed ruler substrate, each pole-opposing unit comprises at least three sensing electrode groups arranged at intervals along a length direction of the moved ruler substrate, each of the sensing electrode groups comprises an excitation electrode and an induction electrode 10 that are arranged at intervals along the length direction of the moved ruler substrate, a distance between the excitation electrode and the induction electrode in each sensing electrode group is identical, and all the excitation electrodes and induction electrodes are arranged at equal intervals along the length direction of the moved ruler substrate;all the pole-opposing units are evenly spaced along the length direction of the moved 15 ruler substrate, the plurality of sensing electrode groups in the pole-opposing units are £yj evenly spaced along the length direction of the moved ruler substrate, the excitationelectrodes located at arrangement sequence positions along the length direction of the -j— moved ruler substrate in the pole-opposing unit are respectively electrically connected to Q} the excitation electrodes located at corresponding arrangement sequence positions along C\J 20 the length direction of the moved ruler substrate in the other pole-opposing units, and all the induction electrodes are electrically connected together; anda plurality of modulation unit groups arranged along a length direction of the fixed ruler substrate are arranged on a side surface of the fixed ruler substrate facing a direction of the moved ruler substrate, all the pole-opposing units on the moved ruler substrate can 25 respectively correspond to a same number of adj acent modulation unit groups on the fixed ruler substrate along the length direction of the fixed ruler substrate, each pole-opposing unit can correspond to a modulation unit group, each modulation unit group comprises 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 units G 30 are alternately arranged along the length direction of the fixed ruler substrate, and the modulation unit F can correspond to at least one sensing electrode group in the poleopposing unit along the length direction of the fixed ruler substrate.

2. The linear displacement sensor based on electric field self-coupling according to29 12 25claim 1, wherein the material of the modulation unit F or the material of the modulation unit G is the same as that of the fixed ruler substrate.

3. The linear displacement sensor based on electric field self-coupling according to claim 1, wherein the modulation unit F, the modulation unit G, and the fixed ruler 5 substrate are all made of different materials.

4. The linear displacement sensor based on electric field self-coupling according to claim 1, wherein the modulation unit F and the modulation unit G are located on a same plane, or a plane where the modulation unit F is located is parallel to a plane where the modulation unit G is located.10 5. The linear displacement sensor based on electric field self-coupling according toclaim 1, wherein a cross-section shape of the modulation unit F is a central rotation symmetric figure.

6. The linear displacement sensor based on electric field self-coupling according to claim 5, wherein the cross-section shape of the modulation unit F is any one of a circle, a 15 square, an ellipse, a rhombus, a hyperbolic sine shape, an oblique cosine shape, or a hyperbolic cosine shape.

Images