Angular displacement sensor based on electric field modulation

Abstract

An angular displacement sensor based on electric field modulation. The sensor comprises a stator base (1) and a rotor base (2) which are arranged one above the other. One or more pole-pair units are provided on the side surface of the stator base (1) facing the rotor base (2), each pole-pair unit comprises at least three sensing electrode groups which are arranged at intervals circumferentially around the center of the stator base (1), and each sensing electrode group comprises one excitation electrode (1-1) and one sensing electrode (1-2) which are spaced apart circumferentially around the center of the stator base (1); and modulation unit groups, the number of which matches that of pole-pair units and which can respectively correspond to the pole-pair units circumferentially around the center of the rotor base (2) are provided on the side surface of the rotor base (2) facing the stator base (1), each modulation unit group comprises one modulation unit F (2-1) and one modulation unit G (2-2) which are arranged circumferentially around the center of the rotor base (2), and the modulation unit F (2-1) can correspond to at least one sensing electrode group in the pole-pair units circumferentially around the center of the rotor base (2).

Description

Angular displacement sensor based on electric field modulation TECHNICAL FIELD

[0001] The present application relates to the field of measurement sensor technology, in particular to an angular displacement sensor based on electric field modulation. BACKGROUND

[0002] With the rapid development of industrial technology, human beings have higher and higher requirements for precision displacement 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 angular displacement sensor (publication number CN103968750A) has been disclosed in the prior art, which uses clock pulse as displacement measurement reference, so it can get rid of the restriction of scale line process, and has higher measurement accuracy. However, the output signal of the sensor is led out by the wire on the rotor, and when the rotor rotates, a slip ring is needed to solve the problem of rotor lead, so its structure is complex, which is not conducive to the miniaturization 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 an angular displacement sensor based on electric field modulation with simple and reliable structure, which can realize passive sensing of the rotor and solve the problem of rotor lead.

[0006] To solve the above technical problems, the present application adopts the following technical scheme:

[0007] An angular displacement sensor based on electric field modulation, comprising a stator base and a rotor base arranged on the same center line, the opposite sides of the stator base and the rotor base are parallel to each other with a gap, one or more pairs of polar units are arranged on the side of the stator base facing the direction of the rotor base, the pairs of polar units 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 induction electrode arranged at intervals around the center of the stator base, the gap between the excitation electrode and the induction electrode in each group of sensing electrode groups occupies the same central angle of the circumference, and all excitation electrodes and induction electrodes are arranged at intervals and staggered around the center of the stator base.

[0008] When there is only one pair of pole unit, the multiple groups of sensing electrode groups in the pair of pole unit are arranged uniformly around the center of the stator base; when there are multiple pair of pole units, all the pair of pole units are arranged uniformly around the center of the stator base, and the multiple groups of sensing electrode groups in the pair of pole unit are arranged around the center of the stator base, the central angle of the gap between the two adjacent groups of sensing electrode groups in the single pair of pole unit is the same, and the excitation electrodes at the respective arrangement sequence positions around the center of the stator base are electrically connected together with the excitation electrodes at the corresponding arrangement sequence positions around the center of the stator base in the other pair of pole units, and all the sensing electrodes are electrically connected together;

[0009] The side of the rotor base facing the direction of the stator base is provided with a plurality of modulation unit groups corresponding to the number of the pair of pole units and capable of being respectively corresponding to the respective pair of pole units around the center of the rotor base, each modulation unit group comprising one modulation unit F and one modulation unit G arranged around the center of the rotor base, the modulation unit F and the modulation unit G being made of different materials, the modulation unit F being capable of corresponding to at least one group of sensing electrode groups in the pair of pole units around the center of the rotor base, and when the number of the modulation unit groups is multiple, all the modulation unit F and the modulation unit G are arranged alternately around the center of the rotor base.

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

[0011] As an optimization, the modulation unit F, the modulation unit G and the rotor base 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 rhombus, 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 of the sensor in the present application are located on the stator base, the passive sensing of the rotor base can be realized, and the problem of rotor lead is solved; the material of the modulation unit on the rotor base can be metal or non-metal, and is not restricted by manufacturing material and manufacturing process, so the detection range is wider; the strength of the sensor output signal is not limited by the number of the excitation unit and the sensing unit, and the transmission efficiency of the signal input and output is higher. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0018] Figure 3 is a schematic diagram of the angle displacement signal calculation process in embodiment 1 of the present application;

[0019] Figure 4 is a schematic diagram of a three-dimensional structure of embodiment 2 of the present application;

[0020] Figure 5 is a schematic diagram of the corresponding structure of the pole unit and modulation unit F and modulation unit G in embodiment 2 of the present application;

[0021] Figure 6 is a schematic diagram of the corresponding structure of the pole unit and modulation unit F and modulation unit G in embodiment 3 of the present application;

[0022] Figure 7 is a schematic diagram of the corresponding structure of the pole unit and modulation unit F and modulation unit G in embodiment 4 of the present application;

[0023] Figure 8 is a schematic diagram of a three-dimensional structure of a rotor base in embodiment 5 of the present application;

[0024] Figure 9 is a schematic diagram of a three-dimensional structure of a rotor base in embodiment 6 of the present application;

[0025] Figure 10 is a schematic diagram of a three-dimensional structure of a rotor base in embodiment 7 of the present application;

[0026] Figure 11 is a schematic diagram of a three-dimensional structure of a rotor base in embodiment 8 of the present application;

[0027] Figure 12 is a top view of a rotor base in embodiment 9 of the present application;

[0028] Figure 13 is a top view of a rotor base in embodiment 10 of the present application;

[0029] Figure 14 is a top view of a rotor base in embodiment 11 of the present application;

[0030] Figure 15 is a top view of a rotor base in embodiment 12 of the present application;

[0031] Figure 16 is a top view of a rotor base in embodiment 13 of the present application;

[0032] Figure 17 is a top view of a rotor base in embodiment 14 of the present application;

[0033] Figure 18 is a top view of a rotor base in embodiment 15 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 only 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 explained 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, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply 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 a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation 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 explained 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 detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or 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 angular displacement sensor based on electric field modulation in the present embodiment comprises a stator base 1 and a rotor base 2 arranged in the same center line, the side surface of the stator base 1 opposite to the rotor base 2 is parallel to the side surface of the rotor base 2 with a gap, a plurality of antipodal units are arranged on the side surface of the stator base 1 facing the direction of the rotor base 2, each antipodal unit comprises four groups of sensing electrode groups arranged in the circumferential direction of the stator base 1 with a gap, each group of sensing electrode groups comprises one excitation electrode 1-1 and one induction electrode 1-2 arranged in the circumferential direction of the stator base 1 with a gap, the central angle of the gap 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 arranged in the circumferential direction of the stator base 1 with a gap.

[0038] All the antipodal units are arranged in the circumferential direction of the stator base 1 with a uniform gap, and the groups of sensing electrode groups in the antipodal units are arranged in the circumferential direction of the stator base 1 with a gap, the central angle of the gap between the two adjacent groups of sensing electrode groups in a single antipodal unit is the same, the excitation electrodes 1-1 at each arrangement sequence position in the circumferential direction of the stator base 1 in the antipodal unit are electrically connected together with the excitation electrodes 1-1 at the corresponding arrangement sequence position in the circumferential direction of the stator base 1 in the other 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 other 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 other 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 other antipodal units to form an excitation unit group C3, the excitation electrodes 1-1 at the seventh arrangement sequence position in the antipodal unit are electrically connected together with all the excitation electrodes 1-1 at the seventh arrangement sequence position in the other antipodal units to form an excitation unit group D4 (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 other antipodal units to form an excitation unit group M, and so on), and then all the induction electrodes 1-2 in the antipodal units are electrically connected together to form an induction unit group E. N

[0039] ​The rotor base 2 is provided with modulation unit groups on the side surface thereof and in the direction of the stator base 1, the number of the modulation unit groups being consistent with that of the pole units, each modulation unit group comprising one modulation unit F2-1 and one modulation unit G2-2 arranged around the center of the rotor base 2, the modulation unit F2-1 and the modulation unit G2-2 being made of different materials, the modulation unit F2-1 in each modulation unit group being capable of corresponding to one group of sensing electrode groups in the pole unit around the center of the rotor base 2, and the modulation unit G2-2 in the modulation unit group being capable of corresponding to the remaining three groups of sensing electrode groups in the same pole unit, all the modulation units F2-1 and the modulation units G2-2 being staggered around the center of the rotor base 2.

[0040] During measurement, four groups of excitation units A1, B2, C3 and D4 on the stator base 1 are respectively given equal-amplitude and same-frequency sinusoidal voltage signals U 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), (if the number of the groups of excitation units is more than four, then the corresponding groups of excitation units A, B, C, D, …, M N are respectively given 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 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: Uo=KeU m sin(ωt+K θ θ)

[0041] 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.

[0042] During measurement, as shown in Figure 3 in this specific embodiment, 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.

[0043] In this specific embodiment, the modulation unit F2-1 and the modulation unit G2-2 are located on the same plane.

[0044] Example 2

[0045] As another embodiment of the present invention, as shown in Figures 4 and 5, in this specific embodiment, the number of pole units is one. 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.

[0046] Embodiment 3

[0047] As another embodiment of the present application, as shown in Fig. 6, in this embodiment, a plurality of antipodal units are provided on the stator base 1, each of which contains four groups of sensing electrode groups, and the modulation units F2-1 on the rotor base 2 can correspond to two groups of sensing electrode groups in the antipodal units in the circumferential direction of the rotor base 2, and the modulation units G2-2 correspond to two groups of sensing electrode groups in the same antipodal unit.

[0048] Embodiment 4

[0049] As another embodiment of the present application, as shown in Fig. 7, in this embodiment, a plurality of antipodal units are provided on the stator base 1, each of which contains four groups of sensing electrode groups, and the modulation units F2-1 on the rotor base 2 can correspond to three groups of sensing electrode groups in the antipodal units in the circumferential direction of the rotor base 2, and the modulation units G2-2 correspond to one group of sensing electrode groups in the same antipodal unit.

[0050] Embodiment 5

[0051] As another embodiment of the present application, as shown in Fig. 8, in this embodiment, the rotor base 2 and the modulation units F2-1 are made of the same material, and the modulation units G2-2 are made of a material different from the two, and the plane on which the modulation units F2-1 are located and the plane on which the modulation units G2-2 are located are not in the same plane, but the two planes are parallel.

[0052] Embodiment 6

[0053] As another embodiment of the present application, as shown in Fig. 9, in this embodiment, the rotor base 2 and the modulation units G2-2 are made of the same material, and the modulation units F2-1 are made of a material different from the two, and the plane on which the modulation units F2-1 are located and the plane on which the modulation units G2-2 are located are not in the same plane, but the two planes are parallel.

[0054] Embodiment 7

[0055] As another embodiment of the present application, as shown in Fig. 10, in this embodiment, the rotor base 2, the modulation units F2-1 and the modulation units G2-2 are made of different materials, respectively, and the modulation units F2-1 and the modulation units G2-2 are located on the same plane.

[0056] Embodiment 8

[0057] As another embodiment of the present application, as shown in Fig. 11, in the present embodiment, the rotor base 2, the modulation unit F2-1 and the modulation unit G2-2 are made of different materials, respectively, and the planes where the modulation unit F2-1 and the modulation unit G2-2 are located are not in the same plane, but the planes where the two are located are parallel.

[0058] Example 9

[0059] 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.

[0060] Example 10

[0061] 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.

[0062] Example 11

[0063] 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.

[0064] Example 12

[0065] 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-shaped.

[0066] Example 13

[0067] 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-shaped.

[0068] Example 14

[0069] 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 cosine-cotangent-shaped.

[0070] Example 15

[0071] 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-shaped.

[0072] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and 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 technical solutions should be covered in the scope of the claims of the present application.

Claims

1. An angular displacement sensor based on electric field modulation, comprising a stator base and a rotor base arranged coaxially, the side surfaces of the stator base and the rotor base opposite to each other are parallel and have a gap, characterized in that: One or more pairs of opposite units are arranged on the side surface of the stator base and face the direction of the rotor base, the pairs of opposite units include at least three groups of sensing electrode groups arranged at intervals around the center of the stator base, each group of sensing electrode groups includes one excitation electrode and one induction electrode arranged at intervals around the center of the stator base, the central angle of the gap 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 around the center of the stator base; When there is only one pair of opposite units, the multiple groups of sensing electrode groups in the pair of opposite units are arranged at intervals around the center of the stator base; when the number of pairs of opposite units is multiple, all the pairs of opposite units are arranged at intervals around the center of the stator base, and the multiple groups of sensing electrode groups in the pairs of opposite units are arranged at intervals around the center of the stator base, the central angle of the gap between the adjacent two groups of sensing electrode groups in a single pair of opposite units is the same, and the excitation electrodes at the respective arrangement sequence positions around the center of the stator base in the pair of opposite units are electrically connected together with the excitation electrodes at the corresponding arrangement sequence positions around the center of the stator base in the remaining pairs of opposite units, and all the induction electrodes are electrically connected together; The rotor base is provided with a number of modulation unit groups on the side surface thereof and facing the direction of the stator base, the number of modulation unit groups is consistent with the number of pairs of opposite units, and each modulation unit group can correspond to each pair of opposite units around the center of the rotor base, each modulation unit group includes one modulation unit F and one 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 group of sensing electrode groups in the pair of opposite units around the center of the rotor base, and when the number of modulation unit groups is multiple, all the modulation units F and the modulation unit G are arranged at intervals around the center of the rotor base.

2. The electric field modulation based angular displacement sensor according to claim 1, characterized in that: The material of the modulation unit F or the modulation unit G is consistent with the material of the rotor base.

3. The electric field modulation based angular displacement sensor of claim 1, wherein: The modulation unit F, the modulation unit G and the rotor base are made of different materials.

4. The electric field modulation based angular displacement sensor of claim 1, wherein: 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.

5. The electric field modulation based angular displacement sensor of claim 1, wherein: The cross-sectional shape of the modulation unit F is a central rotationally symmetric figure.

6. The electric field modulation based angular displacement sensor according to claim 5, characterized in that: The cross-sectional shape of the modulation unit F is any one of a circle, a square, an ellipse, a rhombus, a double sine shape, a slant cosine shape or a double cosine shape.

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