Angular displacement sensor based on electric field modulation

Abstract

The application discloses an angular displacement sensor based on electric field modulation, which comprises a stator base and a rotor base arranged in a top-bottom mode, one or more pairs of electrodes are arranged on the side surface of the stator base and face the direction of the rotor base, the pairs of electrodes comprise at least three groups of sensing electrode groups arranged at intervals around the center of the stator base, each group of sensing electrode groups comprises one excitation electrode and one sensing electrode arranged at intervals around the center of the stator base; the rotor base is provided with a plurality of modulation unit groups on the side surface and faces the direction of the stator base, the number of the modulation unit groups is consistent with that of the pairs of electrodes, and each modulation unit group can correspond to each pair of electrodes around the center of the rotor base, each modulation unit group comprises one modulation unit F and one modulation unit G arranged around the center of the rotor base, and the modulation unit F can correspond to at least one group of sensing electrode groups in the pairs of electrodes around the center of the rotor base.

Description

Technical Field

[0001] This invention relates to the field of measurement and sensing technology, and specifically to an angular displacement sensor based on electric field modulation. 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 for an electric field-type time-grid angular displacement sensor (publication number CN103968750A) uses a clock pulse as the displacement measurement reference, thus eliminating the constraints of the scribing process and achieving higher measurement accuracy. However, the sensor's output signal is led out from the wires on the rotor. During rotor rotation, slip rings are required to manage the rotor lead wires, resulting in a complex structure that hinders sensor miniaturization. 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 an electric field modulation-based angular displacement sensor with a simple and reliable structure that can realize passive sensing of the rotor and solve the rotor lead wire problem.

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

[0006] An angular displacement sensor based on electric field modulation includes a stator base and a rotor base arranged with the same center line at their top and bottom. The side surfaces of the stator base and the rotor base opposite to each other are parallel to each other and have a gap. One or more pole-counter units are arranged on the side surface of the stator base facing the direction of the rotor base. The pole-counter unit includes at least three sets of sensing electrode groups arranged at intervals around the center direction of the stator base. Each set of sensing electrode groups includes an excitation electrode and a sensing electrode arranged at intervals around the center direction of the stator base. The central angle of the circumference occupied by the gap between the excitation electrode and the sensing electrode in each set of sensing electrode groups is the same. All excitation electrodes and sensing electrodes are arranged alternately around the center direction of the stator base.

[0007] When there is only one counter pole unit, the multiple sets of sensing electrodes in the counter pole unit are evenly spaced around the center of the stator base. When there are multiple counter pole units, all the counter pole units are evenly spaced around the center of the stator base, and the multiple sets of sensing electrodes in the counter pole unit are spaced around the center of the stator base. The central angle of the circumference occupied by the gap between two adjacent sets of sensing electrodes in a single counter pole unit is the same. The excitation electrodes located at the positions of the arrangement sequence around the center of the stator base in the counter pole unit are electrically connected to the excitation electrodes at the corresponding positions of the arrangement sequence around the center of the stator base in the other counter pole units. All the sensing electrodes are electrically connected together.

[0008] On the rotor base and on one side facing the stator base, there are modulation unit groups that are the same number as the number of counter pole units and can correspond to each counter pole unit around the center of the rotor base. Each modulation unit group includes a modulation unit F and a modulation unit G arranged around the center of the rotor base. The modulation unit F and the modulation unit G are made of different materials. The modulation unit F can correspond to at least one set of sensing electrodes in the counter pole unit around the center of the rotor base. When there are multiple modulation unit groups, all the modulation units F and the modulation unit G are staggered around the center of the rotor base.

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

[0010] As an optimization, the modulation unit F, the modulation unit G, and the rotor 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 the prior art, the present invention has the following advantages: the signal input and output of the sensor in the present invention are both located on the stator base, which can realize passive sensing of the rotor base and solve the rotor lead wire problem; the material of the modulation unit on the rotor base can be metal or non-metal, which is not limited by the manufacturing material and manufacturing process, and can detect a wider range; the intensity of the sensor output signal is not limited by the number of excitation unit and sensing unit, and its signal input and output transmission efficiency is higher. 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 angular displacement signal calculation process in Embodiment 1 of the present invention;

[0018] Figure 4 This is a three-dimensional structural schematic diagram of 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 2 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 3 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 4 of the present invention;

[0022] Figure 8 This is a three-dimensional structural diagram of the rotor base in Embodiment 5 of the present invention;

[0023] Figure 9 This is a three-dimensional structural diagram of the rotor base in Embodiment 6 of the present invention;

[0024] Figure 10 This is a three-dimensional structural diagram of the rotor base in Embodiment 7 of the present invention;

[0025] Figure 11 This is a three-dimensional structural diagram of the rotor base in Embodiment 8 of the present invention;

[0026] Figure 12 This is a top view of the rotor base in Embodiment 9 of the present invention;

[0027] Figure 13 This is a top view of the rotor base in Embodiment 10 of the present invention;

[0028] Figure 14 This is a top view of the rotor base in Embodiment 11 of the present invention;

[0029] Figure 15 This is a top view of the rotor base in Embodiment 12 of the present invention;

[0030] Figure 16 This is a top view of the rotor base in Embodiment 13 of the present invention;

[0031] Figure 17 This is a top view of the rotor base in Embodiment 14 of the present invention;

[0032] Figure 18 This is a top view of the rotor base in Embodiment 15 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 electric field modulation-based angular displacement sensor in this specific embodiment includes a stator base 1 and a rotor base 2 arranged with the same center line at the top and bottom. The side surfaces of the stator base 1 and the rotor base 2 opposite to each other are parallel to each other and have a gap. Multiple pole-counter units are arranged on the side surface of the stator base 1 facing the direction of the rotor base 2. The pole-counter unit includes four groups of sensing electrodes arranged at intervals around the center of the stator base 1. Each group of sensing electrodes includes an excitation electrode 1-1 and a sensing electrode 1-2 arranged at intervals around the center of the stator base 1. The central angle of the circumference occupied by the gap 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 at intervals and alternately around the center of the stator base 1.

[0037] All counter pole units are evenly spaced around the center of the stator base 1, and multiple sets of sensing electrodes in each counter pole unit are also spaced around the center of the stator base 1. The central angle of the circumference occupied by the gap between two adjacent sets of sensing electrodes in a single counter pole unit is the same. The excitation electrode 1-1 located at each position in the arrangement sequence around the center of the stator base 1 in each counter pole unit is electrically connected to the corresponding excitation electrode 1-1 in the other counter pole units. All sensing electrodes 1-2 are electrically connected together. That is, the excitation electrode 1-1 located at the first position in the arrangement sequence of the counter pole unit is electrically connected to all the excitation electrodes 1-1 located at the first position in the arrangement sequence of the other counter pole units to form excitation unit group A1. The excitation electrode located at the third position in the arrangement sequence of the counter pole unit is... 1-1, each electrically connected to all excitation electrodes 1-1 in the third position of the remaining counter electrode units, forms excitation unit group B2. The excitation electrode 1-1 in the fifth position of the counter electrode unit, each electrically connected to all excitation electrodes 1-1 in the fifth position of the remaining counter electrode units, forms excitation unit group C3. The excitation electrode 1-1 in the seventh position of the counter electrode unit, each electrically connected to all excitation electrodes 1-1 in the seventh position of the remaining counter electrode units, forms excitation unit group D4. (If the counter electrode unit includes multiple sets of sensing electrode groups, this continues, with the excitation electrode 1-1 in the Nth position of the counter electrode unit, each electrically connected to all excitation electrodes 1-1 in the Nth position of the remaining counter electrode units, forming excitation unit group M.) N Then, the sensing electrodes 1-2 in all the opposing pole units are electrically connected together to form a sensing unit group E;

[0038] On the rotor base 2, on one side facing the stator base 1, there are modulation unit groups that correspond to each pole pair unit in number and can be arranged around the center of the rotor base 2. Each modulation unit group includes a modulation unit F2-1 and a modulation unit G2-2 arranged around the center of the rotor base 2. The modulation unit F2-1 and the modulation unit G2-2 are made of different materials. The modulation unit F2-1 in each modulation unit group can be aligned with a set of sensing electrodes in the pole pair unit around the center of the rotor base 2. Then the modulation unit G2-2 in the modulation unit group can be aligned with the remaining three sets of sensing electrodes in the same pole pair unit. All the modulation units F2-1 and G2-2 are arranged alternately around the center of the rotor base 2.

[0039] During measurement, equal-amplitude, same-frequency sinusoidal voltage signals U, with phase differences of π / 2, are applied to the four excitation unit groups A1, B2, C3, and D4 on the sub-substrate 1, respectively. A1 =U m sinωt,U B2 =U m sin(ωt+π / 2), U C3 =U m sin(ωt+π), U D4 =U m sin(ωt+3π / 2), (The number of excitation unit groups is multiple, then the corresponding ones are A, B, C, D...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), ...

[0040] U MN =U msin(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 stator base 1 form a capacitor structure. When the dielectric between the capacitors is uniform and unchanged, the signals of the excitation electrode 1-1 cancel each other out, and the output signal of the induction electrode 1-2 group E is always zero. When the rotor base 2 and the stator base 1 are installed coaxially and parallel with a certain gap h, the induction electrode 1-2 group E generates an output signal. When the rotor base 2 and the stator base 1 rotate relative to each other, the modulation units F2-1 and G2-2 of different materials arranged alternately on the rotor base 2 will cause the dielectric between the capacitors formed by the excitation electrode 1-1 and the induction electrode 1-2 to change, thereby causing the induction unit group E to generate an output signal Uo that is linearly related to the angular displacement:

[0041] Uo=KeU m sin(ωt+K θ θ)

[0042] The excitation voltage amplitude U m =25V, frequency f=40kHz, angular frequency ω=2πf=8×10 4 π, Ke is the electric field coupling coefficient, K θ θ is the angular displacement coefficient, and θ is the measured angular displacement.

[0043] During measurement, in this specific embodiment, such as Figure 3 As shown, after the rotor base rotates by an angle θ relative to the stator 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 a 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 angular displacement θ of the rotor base rotating relative to the stator base can be obtained by converting the interpolated count value.

[0044] In this specific embodiment, the modulation unit F2-1 and the modulation unit G2-2 are located on the same plane.

[0045] Example 2

[0046] As another embodiment of the present invention, such as Figure 4 and Figure 5As shown, in this specific embodiment, there is one pole unit. The pole unit includes three sets of sensing electrode groups arranged at intervals around the center of the stator base 1. That is, on the stator base 1, only one set of excitation unit group A1, one set of excitation unit group B2, and one set of excitation unit group C3 are distributed around the entire circumference. The modulation unit F2-1 on the rotor base can correspond to one set of sensing electrode groups in the pole unit around the center of the rotor base 2. The modulation unit G2-2 corresponds to two sets of sensing electrode groups in the same pole unit. The angular displacement measurement can be realized by the above method.

[0047] Example 3

[0048] As another embodiment of the present invention, such as Figure 6 As shown in this specific embodiment, the stator base 1 is provided with multiple counter pole units, each counter pole unit contains four sets of sensing electrode groups, and the modulation unit F2-1 on the rotor base 2 can correspond to two sets of sensing electrode groups in the counter pole unit in the direction of the center of the rotor base 2, and the modulation unit G2-2 corresponds to two sets of sensing electrode groups in the same counter pole unit.

[0049] Example 4

[0050] As another embodiment of the present invention, such as Figure 7 As shown in this specific embodiment, the stator base 1 is provided with multiple counter pole units, each counter pole unit contains four sets of sensing electrode groups, and the modulation unit F2-1 on the rotor base 2 can correspond to three sets of sensing electrode groups in the counter pole unit in the direction of the center of the rotor base 2, and the modulation unit G2-2 corresponds to one set of sensing electrode groups in the same counter pole unit.

[0051] Example 5

[0052] As another embodiment of the present invention, such as Figure 8 As shown, in this specific embodiment, the rotor 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 6

[0054] As another embodiment of the present invention, such as Figure 9 As shown, in this specific embodiment, the rotor 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 7

[0056] As another embodiment of the present invention, such as Figure 10 As shown, in this specific embodiment, the rotor 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 8

[0058] As another embodiment of the present invention, such as Figure 11 As shown, in this specific embodiment, the rotor 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 9

[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 10

[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 11

[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 12

[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 13

[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 14

[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 15

[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. An angular displacement sensor based on electric field modulation, comprising a stator base and a rotor base arranged with their upper and lower centers aligned, wherein the opposite sides of the stator base and the rotor base are parallel to each other and have a gap between them, characterized in that: Multiple pole-counter units are provided on one side of the stator base facing the direction of the rotor base. Each pole-counter unit includes at least three sets of sensing electrode groups arranged at intervals around the center of the stator base. Each set of sensing electrode groups includes an excitation electrode and a sensing electrode arranged at intervals around the center of the stator base. The central angle of the circumference occupied by the gap between the excitation electrode and the sensing electrode in each set of sensing electrode groups is the same. All excitation electrodes and sensing electrodes are arranged alternately around the center of the stator base. When there are multiple counter pole units, all counter pole units are evenly spaced around the center of the stator base, and multiple sets of sensing electrode groups in the counter pole units are spaced around the center of the stator base. The central angle of the circumference occupied by the gap between two adjacent sets of sensing electrode groups in a single counter pole unit is the same. The excitation electrodes located at the positions of the arrangement sequence around the center of the stator base in the counter pole units are electrically connected to the excitation electrodes at the corresponding positions of the arrangement sequence around the center of the stator base in the other counter pole units. All sensing electrodes are electrically connected together. On the rotor base and on one side facing the stator base, there are modulation unit groups that are the same number as the number of counter pole units and can correspond to each counter pole unit around the center of the rotor base. Each modulation unit group includes a modulation unit F and a modulation unit G arranged around the center of the rotor base. The modulation unit F and the modulation unit G are made of different materials. The modulation unit F can correspond to at least one set of sensing electrodes in the counter pole unit around the center of the rotor base. When there are multiple modulation unit groups, all the modulation units F and the modulation unit G are staggered around the center of the rotor base.

2. The angular displacement sensor based on electric field modulation 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 rotor substrate.

3. The angular displacement sensor based on electric field modulation according to claim 1, characterized in that: The modulation unit F, the modulation unit G, and the rotor substrate are all made of different materials.

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

6. The angular displacement sensor based on electric field modulation 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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