CN219368646U - Angular displacement sensor based on single alternating electric field - Google Patents

Abstract

The utility model discloses an angular displacement sensor based on a single alternating electric field, which comprises a stator and a rotor coaxially installed with the stator. The base surface of the rotor is provided with an induction electrode, and the base surface of the stator is provided with an excitation electrode and an induction electrode. The surface of the base body of the rotor and the surface of the base body of the stator provided with excitation electrodes are facing and parallel, leaving a gap. In the utility model, the excitation electrode is a single excitation phase, and a single-phase AC excitation signal is used to excite, so that the form of multi-pole sheet opposite poles for multi-field excitation is changed into the form of single-pole sheet opposite poles, which can eliminate mutual interference and interference between multiple excitation electric fields. The problem of complex winding improves the measurement accuracy; at the same time, the number of poles of the sensor is multiplied within the limited sensor size range, and the number of poles measured in the whole cycle is increased, which can effectively improve the spatial resolution of sensor measurement and improve the signal-to-noise Compare.

Description

An Angular Displacement Sensor Based on Single Alternating Electric Field

technical field

The utility model belongs to the field of precision angular displacement measurement, in particular to an angular displacement sensor based on a single alternating electric field.

Background technique

In recent years, a time grating angular displacement sensor using clock pulses as a displacement measurement reference has been developed in China, such as an electric field type time grating angular displacement sensor (also called a capacitive angular displacement sensor) disclosed in CN103968750A. And on this basis, CN113008128A discloses a capacitive angular displacement sensor and its rotor, which adopts a multi-field excitation measurement method with a multi-probe structure. The traveling wave signal is processed to realize angular displacement measurement. But it still has the following problems: (1) Multi-phase excitation will increase the complexity of the excitation signal, and the lead wires between the multi-phase excitation pole pieces will increase the complexity of the lead wires. At the same time, due to the influence of manufacturing errors, it will inevitably cause The lead wire crosstalk between the signals affects the signal quality; (2) multi-phase excitation makes the angular displacement measurement pole pair space the sum of multiple pole pieces, which makes it difficult to increase the number of angular displacement measurement pole pairs within the limited sensor size range. This limits the further improvement of the sensor signal-to-noise ratio.

Contents of the invention

The purpose of this utility model is to provide an angular displacement sensor based on a single alternating electric field to improve the signal-to-noise ratio and measurement accuracy.

An angular displacement sensor based on a single alternating electric field described in the utility model includes a stator and a rotor coaxially installed with the stator. The base surface of the rotor is provided with an induction electrode, and the base surface of the stator is provided with an excitation electrode. The base surface of the rotor of the electrodes is directly opposite to and parallel to the base surface of the stator provided with excitation electrodes, and a gap is left.

The excitation electrodes have the same radial height and a central angle of The M ₂ sector ring pole pieces are arranged in a circle at equal intervals along the circumferential direction, and the M ₂ sector ring pole pieces are connected into a group to form a single excitation phase. The center angle of the interval between two adjacent sector ring pole pieces is for /> The number of opposite poles of the excitation electrode is M ₂ , and the central angle corresponding to one opposite pole is />

The induction electrode is composed of 4M _{and 1} induction pole pieces arranged in a circle at equal intervals along the circumference, and the induction pole pieces numbered 4n+1 are connected into a group to form an induction group A, and the induction pole pieces numbered 4n+2 Slice Ⅰ is connected into a group to form B induction group, the induction pole piece Ⅰ numbered 4n+3 is connected in a group to form C induction group, and the induction pole piece Ⅰ numbered 4n+4 is connected in a group to form D induction group , n takes all integers from 0 to M ₁ -1 in turn, 4M ₁ :M ₂ =4:3; the shape of the induction pole piece is formed by the intersection of two inclined line segments at the starting and ending points and the inner and outer arcs with the same center For a closed figure, the central angle between the starting points of two inclined line segments is The central angle between the starting and ending points of each inclined line segment is /> The central angle of the induction pole piece is /> The central angle opposite to the interval between two adjacent sensing pole pieces on the inner circle is />

During the measurement, a single-phase AC excitation signal is passed into the single excitation phase, the rotor rotates relative to the stator, and the induction signals output by the A, B, C, and D induction groups are calculated by the angular displacement calculation system to obtain the angular displacement value.

Another angular displacement sensor based on a single alternating electric field described in the utility model includes a stator and a rotor coaxially installed with the stator. The base surface of the rotor is provided with an induction electrode, and the base surface of the stator is provided with an excitation electrode. The surface of the base body of the rotor of the induction electrode is directly opposite to and parallel to the surface of the base body of the stator provided with the excitation electrode, and a gap is left.

The excitation electrodes have the same radial height and a central angle of The M ₂ sector ring pole pieces are arranged in a circle at equal intervals along the circumferential direction, and the M ₂ sector ring pole pieces are connected into a group to form a single excitation phase. The center angle of the interval between two adjacent sector ring pole pieces is for /> The number of opposite poles of the excitation electrode is M ₂ , and the central angle corresponding to one opposite pole is />

The induction electrode is composed of 4M _{and 1} induction pole pieces arranged in a circle at equal intervals along the circumference, and the induction pole pieces numbered 4n+1 are connected into a group to form an induction group A, and the induction pole pieces numbered 4n+2 Slice Ⅰ is connected into a group to form B induction group, the induction pole piece Ⅰ numbered 4n+3 is connected in a group to form C induction group, and the induction pole piece Ⅰ numbered 4n+4 is connected in a group to form D induction group , n takes all integers from 0 to M ₁ -1 in turn, 4M ₁ :M ₂ =4:5; the shape of the sensing pole piece is formed by the intersection of two inclined line segments at the starting and ending points and the inner and outer arcs with the same center For a closed figure, the central angle between the starting points of two inclined line segments is The central angle between the starting and ending points of each inclined line segment is /> The central angle of the induction pole piece is /> The central angle opposite to the interval between two adjacent sensing pole pieces on the inner circle is />

During the measurement, a single-phase AC excitation signal is passed into the single excitation phase, the rotor rotates relative to the stator, and the induction signals output by the A, B, C, and D induction groups are calculated by the angular displacement calculation system to obtain the angular displacement value.

Preferably, the two inclined line segments have two forms: the first one is in polar coordinates interval or /> Two identical half-periodic cosine curve segments of the interval; the second type is two diagonal line segments.

Preferably, the angular displacement calculation system includes a first differential module, a second differential module, an RC phase shifting circuit, a third differential module, a signal conversion circuit and a signal processing system, the signal output terminal of the A sensing group, and the C sensing group The signal output terminals of the first differential module are respectively connected to the two input terminals of the first differential module, the signal output terminals of the B induction group and the signal output terminals of the D induction group are respectively connected to the two input terminals of the second differential module, and the signal output terminals of the second differential module The output terminal is connected to the input terminal of the RC phase-shifting circuit, the output terminal of the RC phase-shifting circuit and the output terminal of the first differential module are respectively connected to the two input terminals of the third differential module, and the output terminal of the third differential module is connected to the signal conversion The input end of the circuit is connected, the output end of the signal conversion circuit is connected with the input end of the signal processing system, and the signal processing system outputs the angular displacement value. The angular displacement measurement cycle is That is, one excitation antipolar space corresponds to one measurement period.

In the utility model, the excitation electrode is a single excitation phase, and a single-phase AC excitation signal is used for excitation, which simplifies the structure and generation form of the excitation electrode and the excitation signal, and changes the form of the multi-pole sheet counter-pole for multi-field excitation into a single-pole sheet counter-pole The form eliminates the mutual interference between multi-channel excitation electric fields and complex winding problems, and improves the measurement accuracy; at the same time, within the limited sensor size range, the number of poles of the sensor is increased exponentially, and the number of poles measured in the entire cycle is increased. , which effectively improves the spatial resolution of the sensor measurement and improves the signal-to-noise ratio.

Description of drawings

FIG. 1 is a plan view of a stator in Embodiment 1. FIG.

FIG. 2 is a bottom view of the rotor in Embodiment 1. FIG.

FIG. 3 is a schematic diagram of the corresponding relationship between the rotor and the stator in Embodiment 1. FIG.

FIG. 4 is a partial schematic diagram of the projection relationship between the sensing electrodes and the excitation electrodes in Embodiment 1. FIG.

FIG. 5 is a functional block diagram of the angular displacement calculation system in Embodiment 1.

FIG. 6 is a bottom view of the rotor in Embodiment 2. FIG.

Fig. 7 is a schematic diagram of the corresponding relationship between the rotor and the stator in Embodiment 2.

FIG. 8 is a partial schematic diagram of the projection relationship between the sensing electrodes and the excitation electrodes in Embodiment 2. FIG.

FIG. 9 is a bottom view of the rotor in Embodiment 3. FIG.

Fig. 10 is a schematic diagram of the corresponding relationship between the rotor and the stator in Embodiment 3.

FIG. 11 is a partial schematic diagram of the projection relationship between the sensing electrodes and the excitation electrodes in Embodiment 3. FIG.

FIG. 12 is a bottom view of the rotor in Embodiment 4. FIG.

Fig. 13 is a schematic diagram of the corresponding relationship between the rotor and the stator in Embodiment 4.

FIG. 14 is a partial schematic diagram of the projection relationship between the sensing electrodes and the excitation electrodes in Embodiment 4. FIG.

Detailed ways

Embodiment 1: As shown in Figures 1 to 5, the angular displacement sensor based on a single alternating electric field in this embodiment includes a stator 1 and a rotor 2 coaxially installed with the stator 1; the lower surface of the rotor 2 is provided with Induction electrodes, the upper surface of the base of the stator 1 is provided with an excitation electrode, the lower surface of the base of the rotor 2 is directly parallel to the upper surface of the base of the stator 1, and a gap of 0.5mm is left, and the induction electrode is directly opposite to the excitation electrode. Both the base body of the rotor 2 and the base body of the stator 1 adopt the PCB manufacturing process, and the pole pieces of the excitation electrodes and the pole pieces of the induction electrodes are made by coating copper on the PCB board.

As shown in Figure 1, Figure 3, and Figure 4, the excitation electrode consists of 60 (ie M ₂ =60) fan rings with an inner radius of 15mm, an outer radius of 25mm, a radial height of 10mm, and a central angle of 3° The pole pieces 11 are arranged in a circle at equal intervals clockwise along the circumferential direction, and the central angle between two adjacent sector-shaped pole pieces 11 is 3°. 60 sector-ring pole pieces 11 are connected in series through via holes to form a single excitation phase. The number of pole pairs in the sensor is 60 (that is, the sensor has 60 poles), and the central angle corresponding to one pole is 6°.

As shown in Fig. 2, Fig. 3 and Fig. 4, the sensing electrode is composed of 80 (ie M ₁ =20) sensing pole pieces 21 arranged in a circle at equal intervals clockwise along the circumference, and the number is 4n+1 along the clockwise direction (i.e. No. 1, 5, ..., 73, 77) the induction pole piece 21 is connected into a group through the via hole lead wire to form an induction group A, and the number is 4n+2 (i.e. No. 2, 6, ..., 74, 78 ) Inductive pole pieces 21 are connected into a group through via hole leads to form B induction group, numbered 4n+3 (that is, No. 3, 7, ..., 75, 79) Induction pole pieces 21 are connected into a group through via hole leads, Form C induction group, the number is 4n+4 (that is, No. 4, 8, ..., 76, 80). The induction pole pieces 21 are connected into a group through via-hole leads to form D induction group, and n takes all the numbers from 0 to 19 in turn integer. The shape of the sensing pole piece 21 is a closed figure formed by the intersection of two identical half-period cosine curve segments in the [0,3°] interval under polar coordinates at the starting and ending points and the inner and outer arcs of the same circle center (which can be called oblique cosine surface), the central angle between the starting points of the two identical half-period cosine curve segments is 3°, the central angle between the starting and ending points of each half-period cosine curve segment is 3°, and the induction pole piece 21 The central angle of the pair is 6 °, the central angle of the interval between two adjacent sensing pole pieces 21 on the inner circle is 1.5 °, and the central angle of the interval of two adjacent sensing pole pieces 21 on the outer circle is also is 1.5°, the radius of the inner arc is 16mm, the radius of the outer arc is 24mm, and the radial height of the sensing pole piece 21 is 8mm.

During measurement, a single-phase AC excitation signal _Uc (that is, a sinusoidal AC signal) is passed into a single excitation phase, and the excitation electrode outputs a single-phase AC electric field I _m sin(ωt); where, I _m is the maximum value of the excitation electric field intensity value, ω is the excitation frequency. The rotor 2 rotates relative to the stator 1, and the induction signals output by the induction groups A, B, C, and D are calculated by the angular displacement calculation system to obtain the angular displacement value.

As shown in Figure 5, the angular displacement calculation system includes a first difference module 31, a second difference module 32, an RC phase shift circuit 33 (i.e. a 90° phase shift circuit), a third difference module 34, a signal conversion circuit 35 and a signal Processing system 36 (such as FPGA). The signal output end of the A induction group and the signal output end of the C induction group are respectively connected to the two input ends of the first differential module 31, and the signal output end of the B induction group and the signal output end of the D induction group are respectively connected to the second differential module. The two input terminals of 32 are connected, the output terminal of the second differential module 32 is connected with the input terminal of the RC phase shifting circuit 33, the output terminal of the RC phase shifting circuit 33, the output terminal of the first differential module 31 are respectively connected with the third differential module The two input ends of 34 are connected, the output end of the third differential module 34 is connected to the input end of the signal conversion circuit 35 , the output end of the signal conversion circuit 35 is connected to the input end of the signal processing system 36 . The induction signal output by the A induction group (i.e. the induction signal of the A group) and the induction signal output by the C induction group (i.e. the induction signal of the C group) are differentially amplified by the first differential module 31 to output a sinusoidal standing wave signal U _a , and the B induction group After the output induction signal (i.e. group B induction signal) and the induction signal output by D induction group (i.e. group D induction signal) are differentially amplified by the second differential module 32, the output signal _{U b is} passed through the RC phase shifting circuit 33 (i.e. 90° phase-shifting circuit) output cosine standing wave signal U _b ' after phase shifting, sine standing wave signal U _a and cosine standing wave signal U _b ' are synthesized into one electric traveling wave signal U ₀ after the third differential module 34, The electric traveling wave signal _U0 is converted into a square wave signal by the signal conversion circuit 35, and the square wave signal is passed into the signal processing system 36, and the signal processing system 36 compares the single-phase AC excitation signal _Uc with the traveling wave signal _U0 , and the phase The difference is interpolated by the high-frequency clock pulse, and the angular displacement value is obtained through conversion, and the signal processing system 36 outputs the angular displacement value, and the measurement period of the angular displacement is

Embodiment 2: As shown in Figures 6 to 8, the angular displacement sensor based on a single alternating electric field in this embodiment has the same measurement principle and most of its structure as in Embodiment 1, the difference being:

The induction electrode is composed of 48 (ie M ₁ =12) induction pole pieces 21 arranged in a circle at equal intervals clockwise along the circumference, numbered 4n+1 (ie 1st, 5th, ..., 41, 45th) along the clockwise direction No.) sensing pole pieces 21 are connected into a group through via-hole leads to form an induction group A, and the number is 4n+2 (that is, No. 2, 6, ..., 42, 46). The sensing pole pieces 21 are connected into a group through via-hole leads , to form the B induction group, numbered 4n+3 (that is, No. 3, 7, ..., 43, 47). That is, the 4th, 8th,..., 44th, 48th) sensing pole pieces 21 lead the fourth sensing signal line through the via hole to form a group to form a D sensing group, and n takes all integers from 0 to 11 in turn. The shape of the sensing pole piece 21 is a closed figure formed by the intersection of two identical half-period cosine curve segments in the [0,3°] interval under polar coordinates at the starting and ending points and the inner and outer arcs of the same circle center (which can be called oblique cosine surface), the central angle between the starting points of the two identical half-period cosine curve segments is 3°, the central angle between the starting and ending points of each half-period cosine curve segment is 3°, and the induction pole piece 21 The central angle of the pair is 6 °, the central angle of the interval between two adjacent sensing pole pieces 21 on the inner circle is 4.5 °, and the central angle of the interval of two adjacent sensing pole pieces 21 on the outer circle is also equal to 4.5°.

Embodiment 3: As shown in Figures 9 to 11, the angular displacement sensor based on a single alternating electric field in this embodiment has the same measurement principle and most of its structure as in Embodiment 1, except that:

The shape of the induction pole piece 21 is a closed figure (which can be called an oblique trapezoidal surface) surrounded by two oblique line segments intersecting the inner and outer arcs with the same center at the starting and ending points. The center angle between the starting points of the two oblique line segments is 3°, and the central angle between the start and end points of each oblique segment is 3°.

Embodiment 4: As shown in Figures 12 to 14, the angular displacement sensor based on a single alternating electric field in this embodiment has the same measurement principle and most of its structure as in Embodiment 2, except that:

The shape of the induction pole piece 21 is a closed figure (which can be called an oblique trapezoidal surface) surrounded by two oblique line segments intersecting the inner and outer arcs with the same center at the starting and ending points. The center angle between the starting points of the two oblique line segments is 3°, and the central angle between the start and end points of each oblique segment is 3°.

Claims (5)

1. An angular displacement sensor based on a single alternating electric field comprises a stator (1) and a rotor (2) coaxially arranged with the stator, wherein an induction electrode is arranged on the surface of a matrix of the rotor (2), an excitation electrode is arranged on the surface of the matrix of the stator (1), and the surface of the matrix of the rotor provided with the induction electrode is opposite to and parallel to the surface of the matrix of the stator provided with the excitation electrode, and a gap is reserved; the method is characterized in that:

the exciting electrodes are formed by the radial directions with the same height and the central angle asM of (2) ₂ The fan-shaped annular pole pieces (11) are arranged into a circle at equal intervals along the circumferential direction, M ₂ The fan-shaped annular pole pieces (11) are connected into a group to form a single excitation phase, and the central angle of the interval between two adjacent fan-shaped annular pole pieces (11) is +.>

The induction electrode is formed by 4M ₁ The induction pole pieces (21) are arranged into a circle at equal intervals along the circumferential direction, the induction pole pieces with the number of 4n+1 are connected into a group to form an A induction group, and the number of 4n is 4The induction pole pieces I with the number of +2 are connected into a group to form a B induction group, the induction pole pieces I with the number of 4n+3 are connected into a group to form a C induction group, the induction pole pieces I with the number of 4n+4 are connected into a group to form a D induction group, and n is sequentially 0 to M ₁ All integers of-1, 4M ₁ :M ₂ =4:3; the shape of the induction pole piece (21) is a closed graph formed by intersecting two inclined line segments with concentric inner and outer circular arcs at a start point and a stop point, and the central angle clamped by the start points of the two inclined line segments isThe central angle of the starting point of each inclined line segment is +.>The central angle of the induction pole piece (21) is +.>The central angle of the interval between two adjacent induction pole pieces on the inner circle is +.>

During measurement, a single-phase alternating current excitation signal is introduced into a single excitation phase, the rotor (2) rotates relative to the stator (1), and an induction signal output by the A, B, C, D induction group is resolved by an angular displacement resolving system to obtain an angular displacement value.

2. An angular displacement sensor based on a single alternating electric field comprises a stator (1) and a rotor (2) coaxially arranged with the stator, wherein an induction electrode is arranged on the surface of a matrix of the rotor (2), an excitation electrode is arranged on the surface of the matrix of the stator (1), and the surface of the matrix of the rotor provided with the induction electrode is opposite to and parallel to the surface of the matrix of the stator provided with the excitation electrode, and a gap is reserved; the method is characterized in that:

the exciting electrodes are formed by the radial directions with the same height and the central angle asM of (2) ₂ The fan-shaped annular pole pieces (11) are arranged into a circle at equal intervals along the circumferential direction, M ₂ The fan-shaped annular pole pieces (11) are connected into a group to form a single excitation phase, and the central angle of the interval between two adjacent fan-shaped annular pole pieces (11) is +.>

The induction electrode is formed by 4M ₁ The induction pole pieces (21) are arranged into a circle at equal intervals along the circumferential direction, the induction pole pieces with the number of 4n+1 are connected into a group, an induction group A is formed, the induction pole pieces I with the number of 4n+2 are connected into a group, an induction group B is formed, the induction pole pieces I with the number of 4n+3 are connected into a group, a C induction group is formed, the induction pole pieces I with the number of 4n+4 are connected into a group, a D induction group is formed, and n sequentially takes 0 to M ₁ All integers of-1, 4M ₁ :M ₂ =4:5; the shape of the induction pole piece (21) is a closed graph formed by intersecting two inclined line segments with concentric inner and outer circular arcs at a start point and a stop point, and the central angle clamped by the start points of the two inclined line segments isThe central angle of the starting point of each inclined line segment is +.>The central angle of the induction pole piece (21) is +.>The central angle of the interval between two adjacent induction pole pieces on the inner circle is +.>

During measurement, a single-phase alternating current excitation signal is introduced into a single excitation phase, the rotor (2) rotates relative to the stator (1), and an induction signal output by the A, B, C, D induction group is resolved by an angular displacement resolving system to obtain an angular displacement value.

3. Angular displacement sensor based on a single alternating electric field according to claim 1 or 2, characterized in that: the angular displacement calculation system comprises a first differential module (31), a second differential module (32), an RC phase-shifting circuit (33), a third differential module (34), a signal conversion circuit (35) and a signal processing system (36), wherein the signal output end of an A induction group and the signal output end of a C induction group are respectively connected with two input ends of the first differential module (31), the signal output end of a B induction group and the signal output end of a D induction group are respectively connected with two input ends of the second differential module (32), the output end of the second differential module (32) is connected with the input end of the RC phase-shifting circuit (33), the output end of the RC phase-shifting circuit (33) and the output end of the first differential module (31) are respectively connected with two input ends of the third differential module (34), the output end of the third differential module (34) is connected with the input end of the signal conversion circuit (35), and the output end of the signal conversion circuit (35) is connected with the input end of the signal processing system (36), and the signal processing system (36) outputs the angular displacement value.

4. A single alternating electric field based angular displacement sensor according to claim 3, wherein: the two inclined line segments are in polar coordinatesInterval or->Two identical half-cycle cosine curve segments of a section.

5. A single alternating electric field based angular displacement sensor according to claim 3, wherein: the two inclined line segments are two oblique line segments.