CN112762807B - Planar motor rotor displacement measuring method and device - Google Patents

Planar motor rotor displacement measuring method and device Download PDF

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CN112762807B
CN112762807B CN202011442503.6A CN202011442503A CN112762807B CN 112762807 B CN112762807 B CN 112762807B CN 202011442503 A CN202011442503 A CN 202011442503A CN 112762807 B CN112762807 B CN 112762807B
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displacement
planar motor
sensor
magnetic field
generated
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CN112762807A (en
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胡楚雄
付宏
朱煜
张鸣
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Tsinghua University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
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Abstract

The invention discloses a displacement measurement method and a displacement measurement device for a rotor of a planar motor, wherein the measurement method comprises the following steps: four magnetic induction sensors are arranged on a planar motor rotor according to an elliptical contour or a circumferential contour, and a signal B is obtained after the sampling signals of the four arranged sensors are processedsx、Bcx、BsyAnd BcyAnd performing polynomial calculation on the processed signals to finish measurement. The method of the invention designs the general arrangement form of the sensor according to the characteristics of the periodic magnetic field, and is convenient for selecting and designing the arrangement scheme according to the configuration of the measured device; the periodic characteristics of the magnetic field are utilized for measurement, so that the resolution of a measurement system can be improved, and high subdivision is realized; the measuring method is simple in calculation, avoids calculation of transcendental functions and solves the problem of quadrant judgment, so that the calculation is simple, and real-time high-speed operation is facilitated.

Description

Planar motor rotor displacement measuring method and device
Technical Field
The invention relates to a displacement measurement method of a motor, in particular to a displacement measurement method and a displacement measurement device of a rotor of a planar motor, which are suitable for processing magnetic field signal analysis of the planar motor and realizing precise displacement detection of the planar motor.
Background
Compared with a device which generates power drive by a rotating motor and then converts the power drive into planar motion, the magnetic suspension planar motor which directly utilizes electromagnetic energy to generate planar motion has the characteristics of high output density, low heat consumption and high precision, omits an intermediate conversion device from the rotary motion to the planar motion and then to the planar motion, can make a control object and the motor into an integrated structure, and has the advantages of fast response, high sensitivity, good follow-up property, simple structure and the like.
The magnetic field signals of the planar motor are periodically distributed, and each time the signals change for one period, the signals correspond to a fixed displacement in space. The measuring circuit usually adopts a method of counting signal periods to measure the displacement, and if the signal periods are simply counted, the resolution of the instrument is the displacement corresponding to one signal period. In order to improve the resolution of the instrument, subdivision techniques are required.
Patent CN 102607391B proposes a method for measuring the displacement of a planar motor by measuring the magnetic field intensity through four magnetic induction sensors at specific positions, and signal processing and judgmentWhen the displacement is measured, the displacement in the X direction and the displacement in the Y direction can be measured respectively. The method is simple in calculation, can avoid calculation of transcendental functions and solve the problem of quadrant judgment, and is beneficial to real-time high-speed operation. However, this patent requires "four sensor coordinates are (X)1,Y1),(X3,Y1),(X2,Y2) And (X)4,Y2) Wherein the position coordinate X in the X direction1,X2,X3And X4The distance between the magnetic poles is one fourth of the magnetic field polar distance in the X direction of the planar motor in sequence, and the coordinate Y in the Y direction1,Y2One quarter "of the pole pitch of the magnetic field in the X direction of the planar motor, but this unique position is more critical.
Disclosure of Invention
The invention aims to provide a displacement measuring method of a planar motor rotor of an elliptically-arranged sensor, which is used for measuring the relative displacement of the planar motor rotor and a stator in the direction of X, Y, realizing the subdivision of signal height and enabling the signal processing to be simple and quick; the problem of single sensor arrangement in the prior art is solved, and a universal sensor arrangement mode is provided.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a displacement measurement method for a planar motor rotor comprises the following steps:
the planar motor rotor is sequentially spaced anticlockwise along the outline of an ellipse or a circle
Figure BDA0002822872790000027
Arranging a first sensor (4), a second sensor (5), a third sensor (6) and a fourth sensor (7) in phase, wherein the first sensor deflects an initial phase alpha anticlockwise relative to the X positive direction, if the four magnetic induction sensors are distributed along the outline of an ellipse, two focuses of the ellipse are distributed along the X direction or the Y direction, the length of a half shaft in the X direction is a, the length of a half shaft in the Y direction is b, if the four magnetic induction sensors are distributed along the outline of a circle, the length of a radius of the circle is r, and r is a and b, wherein X, Y is an orthogonal coordinate axis in the plane of the rotor of the planar motor;
recording phase correlation constants related to an initial phase alpha and an ellipse or a circular parameter, and representing an X-direction magnetic field reference value and a Y-direction magnetic field reference value by using the phase correlation constants;
and judging whether the X-direction displacement is generated or not according to the comparison of the difference value of the X-direction magnetic field reference values at the i +1 moment and the i moment with the X-direction displacement resolution delta X, and judging whether the Y-direction displacement is generated or not according to the comparison of the difference value of the Y-direction magnetic field reference values at the i +1 moment and the i moment with the Y-direction displacement resolution delta Y.
Optionally, after determining whether the X-direction displacement and the Y-direction displacement are generated, the method further includes:
if X-direction displacement is generated, the positive and negative of the X-direction displacement are further judged, and if the generated X-direction displacement is positive, the X-direction counting unit nX＝nX+1, if the X-direction displacement is negative, the X-direction counting unit nX＝n X1, updating the reference value of the magnetic field in the X direction to finish the measurement of the displacement in the X direction, and if the displacement in the X direction is not generated, directly finishing the measurement of the displacement in the X direction;
if Y-direction displacement is generated, the positive and negative of the Y-direction displacement are further judged, and if the generated Y-direction displacement is positive, a Y-direction counting unit nY＝nY+1, if the Y-direction shift is negative, the Y-direction counting unit nY＝nY-1, updating the reference value of the magnetic field in the Y direction to complete the measurement of the displacement in the Y direction, and if no displacement in the Y direction is generated, directly completing the measurement of the displacement in the Y direction,
wherein n isXIs an X-direction counting unit, nYIs a Y-direction counting unit.
Optionally, after the displacement measurement in both the X direction and the Y direction is completed, the relative displacement of the planar motor mover in the X direction is calculated to be X ═ nXΔ x, and Y-n relative displacement in the Y directionY·Δy。
Optionally, the phase correlation constant calculation formula is:
Figure BDA0002822872790000021
Figure BDA0002822872790000022
Figure BDA0002822872790000023
Figure BDA0002822872790000024
Figure BDA0002822872790000025
Figure BDA0002822872790000026
Figure BDA0002822872790000031
Figure BDA0002822872790000032
wherein, tauxIs the magnetic field polar distance, tau, in the X direction of the planar motoryIs the magnetic field pole pitch in the Y direction.
Optionally, the representing of the X-direction magnetic field reference value and the Y-direction magnetic field reference value by the phase correlation constant is a magnetic induction signal B of sampling of the first sensor (4), the second sensor (5), the third sensor (6) and the fourth sensor (7)a,Bb,BcAnd BdRespectively processed into X-direction magnetic field reference values B in a signal processing circuitsx、BcxReference value B of magnetic field in Y directionsyAnd BcyThe method comprises the following steps:
the elliptic central magnetic field is recorded as B ═ BM(sinx+siny)，BMThe magnetic induction intensity amplitude of the magnetic field generated by the magnetic steel array is ellipticalThe position coordinates of the four sensors relative to the center of the ellipse obtained by the parametric equation are respectively (acos alpha, bsn alpha), (-asin alpha, bcos alpha), (-acos alpha, -bsn alpha), (asin alpha, -bcos alpha), and then the sampled magnetic induction intensity signals B of the first sensor (4), the second sensor (5), the third sensor (6) and the fourth sensor (7) are obtained according to the periodicity of the magnetic fielda,Bb,BcAnd BdAre respectively as
Figure BDA0002822872790000033
Figure BDA0002822872790000034
Figure BDA0002822872790000035
Figure BDA0002822872790000036
B is to bea,Bb,BcAnd BdIntermediate signal processing is performed to obtain:
Figure BDA0002822872790000037
Figure BDA0002822872790000038
Figure BDA0002822872790000039
Figure BDA00028228727900000310
further obtaining the reference value of the magnetic field in the X direction from (13) to (16)
Figure BDA00028228727900000311
Figure BDA00028228727900000312
Reference value of magnetic field in Y direction
Figure BDA0002822872790000041
Figure BDA0002822872790000042
Optionally, the method for determining whether the X-direction displacement is generated and the method for determining whether the Y-direction displacement is generated are:
if it is
Figure BDA0002822872790000043
If the relative displacement of the planar motor rotor in the X direction is delta X, determining that the planar motor rotor does not generate the relative displacement in the X direction;
if it is
Figure BDA0002822872790000044
If the relative displacement of the planar motor rotor in the Y direction is determined to be delta Y, if the relative displacement of the planar motor rotor in the Y direction is not determined to be delta Y, the planar motor rotor is determined not to generate the relative displacement in the Y direction,
where i represents time.
Optionally, the following method is adopted for judging the positive and negative of the displacement in the X direction and the positive and negative of the displacement in the Y direction:
if B is(i+1)sxBicx-B(i+1)cxBisxIf the displacement in the X direction of the planar motor rotor is greater than or equal to 0, the relative displacement of the planar motor rotor in the X direction is positive, and if the displacement is not greater than 0, the planar motor rotor is in a planar stateThe relative displacement of the motor rotor in the X direction is negative;
if B is(i+1)syBicy-B(i+1)cyBisyAnd if the relative displacement of the planar motor rotor in the Y direction is not positive, the relative displacement of the planar motor rotor in the Y direction is negative.
The invention also provides a displacement measuring device of the planar motor rotor, which is characterized in that the planar motor rotor is sequentially spaced anticlockwise along the outline of an ellipse or a circle
Figure BDA0002822872790000045
-phase arrangement of a first sensor (4), a second sensor (5), a third sensor (6) and a fourth sensor (7), wherein the first sensor is deflected counter-clockwise with respect to the positive X-direction by an initial phase α, wherein if four magnetic induction sensors are distributed along the contour of an ellipse, the two foci of the ellipse are distributed along the X-direction or along the Y-direction, the half axis length in the X-direction is a, the half axis length in the Y-direction is b, if distributed along the contour of a circle, the radius length of the circle is r, r ═ a ═ b, wherein X, Y are orthogonal coordinate axes in the plane of the rotor of the planar motor, the device comprising:
the magnetic field reference value setting module is used for recording phase correlation constants related to an initial phase alpha and an ellipse or circle parameter, and expressing an X-direction magnetic field reference value and a Y-direction magnetic field reference value by using the phase correlation constants;
and the displacement judging module is used for judging whether X-direction displacement is generated or not according to the comparison between the difference value of the X-direction magnetic field reference values at the i +1 moment and the i moment and the X-direction displacement resolution delta X, and judging whether Y-direction displacement is generated or not according to the comparison between the difference value of the Y-direction magnetic field reference values at the i +1 moment and the i moment and the Y-direction displacement resolution delta Y.
Optionally, the method further comprises:
a displacement positive and negative judging module for further judging the positive and negative of the X-direction displacement if the X-direction displacement is generated, and the X-direction counting unit n if the generated X-direction displacement is positiveX＝nX+1, if the X-direction displacement is negative, the X-direction counting unit nX＝n X1, updating the reference value of the magnetic field in the X direction to finish the measurement of the displacement in the X direction, and if the displacement in the X direction is not generated, directly finishing the measurement of the displacement in the X direction;
if Y-direction displacement is generated, the positive and negative of the Y-direction displacement are further judged, and if the generated Y-direction displacement is positive, a Y-direction counting unit nY＝nY+1, if the Y-direction shift is negative, the Y-direction counting unit nY＝nY-1, updating the reference value of the magnetic field in the Y direction to complete the measurement of the displacement in the Y direction, and if no displacement in the Y direction is generated, directly completing the measurement of the displacement in the Y direction,
wherein n isXIs an X-direction counting unit, nYIs a Y-direction counting unit.
Optionally, the displacement calculating module is configured to calculate the relative displacement of the planar motor mover in the X direction as X ═ n after the displacement measurement in both the X direction and the Y direction is completedXΔ x, and Y-n relative displacement in the Y directionY·Δy。
The technical scheme can obtain prominent effect: the displacement measurement of the motor rotor relative to the stator is realized based on the magnetic field of the motor as a detection signal, so that the adverse factors such as difficult sensor installation can be avoided; the resolution of the measuring system can be improved, and high subdivision is realized; in addition, the calculation of the transcendental function is avoided, the quadrant judgment problem is solved, the calculation is simpler, the real-time high-speed operation is facilitated, and the engineering value is higher; in addition, the technical scheme solves the problem of single arrangement of the sensors in the prior art, realizes the elliptical generalization of the arrangement mode of the sensors (namely the sensors are arranged along the ellipse, and the phase difference is 90 degrees), and the generalized arrangement mode increases the design freedom of designers and has higher application value.
Drawings
The above features and technical advantages of the present invention will become more apparent and readily appreciated from the following description of the embodiments thereof taken in conjunction with the accompanying drawings.
FIG. 1 is a schematic diagram of an overall structure of a moving-coil planar motor to which the method for measuring the displacement of a rotor of the planar motor is applied, according to the present invention;
FIG. 2 is a schematic diagram of a general arrangement of positions of a first sensor, a second sensor, a third sensor and a fourth sensor mounted on a planar motor mover;
FIG. 3 is a simplified schematic diagram of one of the general arrangements of the positions of mounting a first sensor, a second sensor, a third sensor and a fourth sensor on a planar motor mover;
fig. 4 is a flowchart of a method for measuring displacement of a rotor of a planar motor according to the present invention.
Wherein, 1-a planar motor stator; 2-magnetic steel array; 3-a planar motor mover; 4-a first sensor; 5-a second sensor; 6-a third sensor; 7-a fourth sensor; 8-signal processing circuit.
Detailed Description
The embodiments of the present invention will be described below with reference to the accompanying drawings. Those of ordinary skill in the art will recognize that the described embodiments can be modified in various different ways, or combinations thereof, without departing from the spirit and scope of the present invention. Accordingly, the drawings and description are illustrative in nature and not intended to limit the scope of the claims. Furthermore, in the present description, the drawings are not to scale and like reference numerals refer to like parts.
The embodiment of the invention provides a displacement measurement method for a planar motor rotor, which comprises the following steps:
four magnetic induction sensors are arranged on a planar motor rotor: as shown in FIG. 1, the first sensor 4, the second sensor 5, the third sensor 6 and the fourth sensor 7 are distributed along an ellipse or a circle, and the first sensor 4, the second sensor 5, the third sensor 6 and the fourth sensor 7 are sequentially spaced counterclockwise on the circumference of the ellipse or the circumference of the circle
Figure BDA0002822872790000061
Phase, wherein the first sensor is deflected counterclockwise by a phase relative to the positive X direction. X, Y is an orthogonal coordinate axis in the plane of the planar motor rotor, and the Z axis is a plane perpendicular to X, Y axes. Wherein, if four magnetic induction sensors
When the semi-axis length of the ellipse is distributed along the circumference of the ellipse, the two focuses of the ellipse are distributed along the X direction or the Y direction, the semi-axis length in the X direction is a, and the semi-axis length in the Y direction is b;
when the circle is distributed along the circumference of the circle, the radius length of the circle is r, and r is a or b.
Referring to fig. 1 and 2, the method for measuring the displacement of the rotor of the planar motor is applied to an arrangement scheme of a sensor of a moving-coil planar motor. The magnetic steel array 2 on the stator 1 of the planar motor generates a magnetic field B ═ BM(sinx + siny), wherein BMThe amplitude of the magnetic induction intensity generated by the magnetic steel array is shown, X is the displacement of the rotor in the X direction, and Y is the displacement of the rotor in the Y direction.
As shown in fig. 2, four magnetic induction sensors are arranged on the planar motor mover 3: the first sensor 4, the second sensor 5, the third sensor 6 and the fourth sensor 7 are distributed along the ellipse, and the first sensor, the second sensor, the third sensor and the fourth sensor are sequentially spaced from each other counterclockwise on the circumference of the ellipse
Figure BDA0002822872790000062
Phase, wherein the first sensor 4 is offset counterclockwise by a phase with respect to the positive X direction.
The phase dependent constants ccx, csx, scx, ssx, ccy, csy, scy and ssy are recorded in relation to the initial phase constant α and the elliptical or circular parameters as follows:
Figure BDA0002822872790000063
Figure BDA0002822872790000064
Figure BDA0002822872790000065
Figure BDA0002822872790000071
Figure BDA0002822872790000072
Figure BDA0002822872790000073
Figure BDA0002822872790000074
Figure BDA0002822872790000075
wherein the polar distance of the magnetic field in the X direction of the planar motor is tauxThe magnetic field pole pitch in the Y direction is tauy；
Setting the X-direction displacement resolution delta X and the Y-direction displacement resolution delta Y, and measuring the magnetic induction intensity amplitude B of the magnetic field generated by the magnetic steel arrayMInitializing the X-direction counting unit nXCount unit n in Y direction of 0Y＝0，
Initializing X-direction magnetic field reference values:
Figure BDA0002822872790000076
reference value of magnetic field in Y direction
Figure BDA0002822872790000077
Wherein B isa0、Bb0、Bc0And Bd0The sampling signals of the first sensor, the second sensor, the third sensor and the fourth sensor are respectively obtained when the planar motor rotor is at the initial position.
Acquiring a first sensor 4, a second sensor 5,The sampling signals of the third sensor 6 and the fourth sensor 7 are Ba、Bb、BcAnd BdA 1 to Ba、Bb、BcAnd BdAre processed into four paths of signals B in a signal processing circuit 8 respectivelysx、Bcx、BsyAnd BcyThe specific meaning of the four signals is as follows: b issx＝BMsinx，Bcx＝BMcosx，Bsy＝BMsiny，Bcy＝BMcosy, the processing formula of the signals acquired by the four sensors is as follows:
Figure BDA0002822872790000078
Figure BDA0002822872790000079
the processing and calculation processes of the four paths of signals are as follows: the elliptic central magnetic field is recorded as B ═ BM(sinx + siny) because the sensors are arranged along an ellipse and differ in phase
Figure BDA00028228727900000710
The phase positions of the four sensors with respect to the center of the ellipse can be obtained from the parametric equation of the ellipse as (acos α, bsina), (-asin α, bcos α), (-acos α, -bsina), (asin α, -bcos α), and the magnetic induction signals of the positions on the four sensors, i.e., the sampling signals B of the first sensor 4, the second sensor 5, the third sensor 6, and the fourth sensor 7, can be obtained from the periodicity of the magnetic fielda,Bb,BcAnd BdAre respectively as
Figure BDA0002822872790000081
Figure BDA0002822872790000082
Figure BDA0002822872790000083
Figure BDA0002822872790000084
B is to bea,Bb,BcAnd BdIntermediate signal processing is performed to obtain:
Figure BDA0002822872790000085
Figure BDA0002822872790000086
Figure BDA0002822872790000087
Figure BDA0002822872790000088
further obtained from (9) to (12)
Figure BDA0002822872790000089
Figure BDA00028228727900000810
Figure BDA00028228727900000811
Figure BDA00028228727900000812
Judging whether X-direction displacement and Y-direction displacement are generated through a signal processing circuit:
if X-direction displacement is generated, the positive and negative of the X-direction displacement need to be further judged, and if the generated X-direction displacement is positive, the X-direction counting unit nX＝nX+1, if the X-direction displacement is negative, the X-direction counting unit nX＝nX-1, updating the X-direction magnetic field reference value Bksx＝Bsx、Bkcx＝BcxCompleting the displacement measurement in the X direction;
if the X-direction displacement is not generated, directly finishing the X-direction displacement measurement;
if Y-direction displacement is generated, the positive and negative of the Y-direction displacement need to be further judged, and if the generated Y-direction displacement is positive, the Y-direction counting unit nY＝nY+1, if the Y-direction shift is negative, the Y-direction counting unit nY＝nY-1, updating the Y-direction magnetic field reference value Bksy＝Bsy、Bkcy＝BcyCompleting the displacement measurement in the Y direction;
if no Y-direction displacement is generated, directly finishing Y-direction displacement measurement;
after the displacement measurement in the X direction and the displacement measurement in the Y direction are both finished, calculating the relative displacement of the planar motor rotor in the X direction as X ═ nXΔ x, and Y-n relative displacement in the Y directionY·Δy；
And repeating the steps S4 to S6 to realize the real-time measurement of the displacement of the planar motor rotor.
Further, the following method is adopted for determining whether the X-directional displacement is generated and whether the X-directional displacement is positive or negative in step S5:
if it is
Figure BDA0002822872790000091
If the relative displacement of the planar motor rotor in the X direction is delta X, determining that the planar motor rotor does not generate the relative displacement in the X direction;
if B is(i+1)sxBicx-B(i+1)cxBisxAnd if the relative displacement of the planar motor rotor in the X direction is not positive, the relative displacement of the planar motor rotor in the X direction is negative.
Further, the determination of whether the Y-directional displacement is generated and the determination of the positive or negative of the Y-directional displacement in step S5 adopt the following methods:
if it is
Figure BDA0002822872790000092
If the relative displacement of the planar motor rotor in the Y direction is determined to be delta Y, and if the relative displacement of the planar motor rotor in the Y direction is not determined to be delta Y, the planar motor rotor is determined not to generate the relative displacement in the Y direction;
if B is(i+1)syBicy-B(i+1)cyBisyAnd if the relative displacement of the planar motor rotor in the Y direction is not positive, the relative displacement of the planar motor rotor in the Y direction is negative. Wherein i is time.
The above judgment conditions are based on:
let B at time isx、Bcx、BsyAnd BcyAre respectively Bisx、Bicx、BisyAnd Bicy. Represented by the formulae (1) to (12), and Bsx、Bcx、BsyAnd BcyDefinition of (A) to (B)isx、Bicx、BisyAnd BicyThe following were used:
Bisx＝BMsinx……(21)
Bicx＝BMcosx……(22)
Bisy＝BMsiny……(23)
Bicy＝BMcosy……(24)
let B be at time i +1sx、Bcx、BsyAnd BcyAre respectively B(i+1)sx、B(i+1)cx、B(i+1)syAnd B(i+1)cy. The motor comprises the following formulas (1) - (12), and a planar motorRelative displacement Delta in X direction generated by rotor from i time to i +1 timexAnd Y-direction relative displacement delta generated from i moment to i +1 moment of the planar motor rotoryIn the case of very small displacements, B(i+1)sx、B(i+1)cx、B(i+1)syAnd B(i+1)cyApproximately as follows:
B(i+1)sx＝BMsin(x+Δx)≈BM(sinx+Δxcosx)……(25)
B(i+1)cx＝BMcos(x+Δx)≈BM(cosx-Δxsinx)……(26)
B(i+1)sy＝BMsin(y+Δy)≈BM(siny+Δycosy)……(27)
B(i+1)cy＝BMcos(y+Δy)≈BM(cosy-Δysiny)……(28)
calculated by the equations (21) to (28):
Figure BDA0002822872790000101
Figure BDA0002822872790000102
a more specific example is described below.
The polar distance tau of the magnetic fieldx＝τyThe resolution Δ X of the displacement in the X direction is 15 μm, the resolution Δ Y of the displacement in the Y direction is 15 μm, and the magnetic induction amplitude of the magnetic field formed by the magnetic steel array is measured to be BM＝80mT。
Preferably, the initial phase α of the first sensor is set to 0, and the four sensors are arranged along a circle with a radius
Figure BDA0002822872790000103
A preferred sensor arrangement is obtained as shown in figure 3.
1) Magnetic steel array on planar motor stator 1The column 2 generates a magnetic field, and four magnetic induction sensors are arranged on the planar motor mover 3: the first sensor 4, the second sensor 5, the third sensor 6 and the fourth sensor 7 are distributed circumferentially, and the first sensor, the second sensor, the third sensor and the fourth sensor are sequentially spaced anticlockwise on the circumference of a circle
Figure BDA0002822872790000104
Phase, wherein the first sensor is rotated counterclockwise by 0 phase relative to the positive X direction, and the sampling signals of the first sensor, the second sensor, the third sensor and the fourth sensor are respectively Ba、Bb、BcAnd BdSampling signal Ba、Bb、BcAnd BdProcessing takes place in the signal processing circuit 8, where the radius of the circle is 8.8375mm, and the constants ccx, csx, scx, ssx, ccy, csy, scy and ssy relating to the initial phase constant α are: ccx-ccy-ssx-ssy-0, csx-csy-scx-scy-1;
2) and measuring the magnetic induction intensity amplitude B of the magnetic field generated by the magnetic steel array by setting the X-direction displacement resolution delta X to be 15 mu m and the Y-direction displacement resolution delta Y to be 15 mu mMInitializing X-direction count unit n at 80mTXCount unit n in Y direction of 0YInitializing X-direction magnetic field reference value as 0
Figure BDA0002822872790000111
Figure BDA0002822872790000112
Reference value of magnetic field in Y direction
Figure BDA0002822872790000113
Wherein B isa0、Bb0、Bc0And Bd0The sampling signals of a first sensor, a second sensor, a third sensor and a fourth sensor when the planar motor rotor is at the initial position are respectively obtained;
3) the measurement is started by obtaining the sampling signals B of the first sensor, the second sensor, the third sensor and the fourth sensora、Bb、BcAnd BdA 1 to Ba、Bb、BcAnd BdAre respectively processed into four paths of signals B in a signal processing circuitsx、Bcx、BsyAnd BcyWherein:
Figure BDA0002822872790000114
Figure BDA0002822872790000115
4) judging whether X-direction displacement and Y-direction displacement are generated through a signal processing circuit:
a. if it is
Figure BDA0002822872790000116
If yes, the relative displacement of the planar motor rotor in the X direction is 15 μm, and the positive and negative of the displacement in the X direction are further judged, if B is not less thanksxBcx-BkcxBsxWhen the positive displacement is more than or equal to 0, the relative displacement of the planar motor rotor in the X direction is positive, nX＝nX+1, if BksxBcx-BkcxBsxIf < 0, the relative displacement of the planar motor rotor in the X direction is negative, nX＝nX-1, updating the updated X-direction magnetic field reference value Bksx＝Bsx、Bkcx＝BcxCompleting the displacement measurement in the X direction;
if it is
Figure BDA0002822872790000117
Then directly finishing X-direction displacement measurement;
b. if it is
Figure BDA0002822872790000118
If yes, the relative displacement of the planar motor rotor in the Y direction is 15 μm, and the positive and negative of the displacement in the Y direction are further judged, if B is not less thanksyBcy-BkcyBsyIf not less than 0, thenThe relative displacement of the rotor of the planar motor in the Y direction is positive, nY＝nY+1, if BksyBcy-BkcyBsyIf < 0, the relative displacement of the rotor of the planar motor in the Y direction is negative, nY＝nY-1, updating the updated X-direction magnetic field reference value Bksy＝Bsy、Bkcy＝BcyCompleting the displacement measurement in the Y direction;
if it is
Figure BDA0002822872790000121
Then the displacement measurement in the Y direction is directly finished;
5) after the displacement measurement in the X direction and the displacement measurement in the Y direction are both finished, calculating the relative displacement of the planar motor rotor in the X direction to be X-15X nXAnd the relative displacement in the Y direction is Y-15 nY；
6) And repeating 3) to 5), so that the displacement of the planar motor rotor is measured in real time.
Through the steps, the method for measuring the displacement of the planar motor rotor is provided, the relative displacement of the planar motor rotor and the planar motor stator in the direction X, Y is respectively measured, the signal height subdivision is realized, and the signal processing is simple and quick; and the sensor arrangement of the method has versatility such that a designer can preferably design a sensor arrangement scheme by a mechanical device, a load position, and the like.
The planar motor rotor is sequentially spaced anticlockwise along the outline of an ellipse or a circle
Figure BDA0002822872790000122
Four magnetic induction sensors are arranged in phase: a first sensor 4, a second sensor 5, a third sensor 6 and a fourth sensor 7, wherein the first sensor is deflected counterclockwise by an initial phase α with respect to the X-positive direction, wherein if four magnetic induction sensors are distributed along the contour of an ellipse, the two foci of the ellipse are distributed along the X-direction or along the Y-direction, the length of the half axis in the X-direction is a, the length of the half axis in the Y-direction is b, if distributed along the contour of a circle, the length of the radius of the circle is r, and r is a b,
x, Y are orthogonal coordinate axes in the plane of the rotor of the planar motor, and the device further comprises:
a constant recording module for recording constants ccx, csx, scx, ssx, ccy, csy, scy and ssy related to the initial phase alpha and the elliptical or circular parameter,
Figure BDA0002822872790000123
Figure BDA0002822872790000124
Figure BDA0002822872790000125
Figure BDA0002822872790000126
Figure BDA0002822872790000127
Figure BDA0002822872790000128
Figure BDA0002822872790000129
Figure BDA00028228727900001210
wherein, tauxIs the magnetic field polar distance, tau, in the X direction of the planar motoryIs the magnetic field pole pitch in the Y direction;
an initialization module for setting the X-direction displacement resolution Deltax and the Y-direction displacement componentResolution deltay, measuring the magnetic induction amplitude B of the magnetic field produced by the magnetic steel arrayMInitializing the X-direction counting unit nXCount unit n in Y direction of 0YWhen the X-direction magnetic field reference value is set to 0:
Figure BDA0002822872790000131
reference value of magnetic field in Y direction
Figure BDA0002822872790000132
Wherein B isa0、Bb0、Bc0And Bd0The sampling signals of a first sensor, a second sensor, a third sensor and a fourth sensor when the planar motor rotor is at the initial position are respectively obtained;
a sampling signal acquisition module for acquiring the sampling signals of the first sensor, the second sensor, the third sensor and the fourth sensor which are respectively Ba、Bb、BcAnd BdA 1 to Ba、Bb、BcAnd BdAre respectively processed into four paths of signals B in a signal processing circuitsx、Bcx、BsyAnd Bcy，
Figure BDA0002822872790000133
Figure BDA0002822872790000134
And the displacement determining module is used for judging whether X-direction displacement is generated or not according to the comparison of the difference value of the X-direction magnetic field reference values at the i +1 moment and the i moment with the X-direction displacement resolution delta X, and judging whether Y-direction displacement is generated or not according to the comparison of the difference value of the Y-direction magnetic field reference values at the i +1 moment and the i moment with the Y-direction displacement resolution delta Y.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A displacement measurement method for a planar motor rotor is characterized by comprising the following steps:
the planar motor rotor is sequentially spaced anticlockwise along the outline of an ellipse or a circle
Figure FDA0002822872780000011
Arranging a first sensor (4), a second sensor (5), a third sensor (6) and a fourth sensor (7) in phase, wherein the first sensor deflects an initial phase alpha anticlockwise relative to the X positive direction, if the four magnetic induction sensors are distributed along the outline of an ellipse, two focuses of the ellipse are distributed along the X direction or the Y direction, the length of a half shaft in the X direction is a, the length of a half shaft in the Y direction is b, if the four magnetic induction sensors are distributed along the outline of a circle, the length of a radius of the circle is r, and r is a and b, wherein X, Y is an orthogonal coordinate axis in the plane of the rotor of the planar motor;
recording phase correlation constants related to an initial phase alpha and an ellipse or a circular parameter, and representing an X-direction magnetic field reference value and a Y-direction magnetic field reference value by using the phase correlation constants;
and judging whether the X-direction displacement is generated or not according to the comparison of the difference value of the X-direction magnetic field reference values at the i +1 moment and the i moment with the X-direction displacement resolution delta X, and judging whether the Y-direction displacement is generated or not according to the comparison of the difference value of the Y-direction magnetic field reference values at the i +1 moment and the i moment with the Y-direction displacement resolution delta Y.
2. The method of claim 1, wherein after determining whether the X-direction displacement and the Y-direction displacement are generated, the method further comprises:
if the displacement in X direction is generated, the positive and negative of the displacement in X direction is further judged,if the resulting X-direction displacement is positive, the X-direction counting unit nX＝nX+1, if the X-direction displacement is negative, the X-direction counting unit nX＝nX1, updating the reference value of the magnetic field in the X direction to finish the measurement of the displacement in the X direction, and if the displacement in the X direction is not generated, directly finishing the measurement of the displacement in the X direction;
if Y-direction displacement is generated, the positive and negative of the Y-direction displacement are further judged, and if the generated Y-direction displacement is positive, a Y-direction counting unit nY＝nY+1, if the Y-direction shift is negative, the Y-direction counting unit nY＝nY-1, updating the reference value of the magnetic field in the Y direction to complete the measurement of the displacement in the Y direction, and if no displacement in the Y direction is generated, directly completing the measurement of the displacement in the Y direction,
wherein n isXIs an X-direction counting unit, nYIs a Y-direction counting unit.
3. The planar motor mover displacement measurement method of claim 2,
after the displacement measurement in the X direction and the displacement measurement in the Y direction are both finished, calculating the relative displacement of the planar motor rotor in the X direction as X ═ nXΔ x, and Y-n relative displacement in the Y directionY·Δy。
4. The method of claim 1, wherein the phase correlation constant calculation formula is:
Figure FDA0002822872780000012
Figure FDA0002822872780000013
Figure FDA0002822872780000014
Figure FDA0002822872780000021
Figure FDA0002822872780000022
Figure FDA0002822872780000023
Figure FDA0002822872780000024
Figure FDA0002822872780000025
wherein, tauxIs the magnetic field polar distance, tau, in the X direction of the planar motoryIs the magnetic field pole pitch in the Y direction.
5. The planar motor mover displacement measurement method of claim 4, wherein the representing of the X-direction and Y-direction magnetic field reference values by the phase-related constants is a magnetic induction signal B of sampling of a first sensor (4), a second sensor (5), a third sensor (6) and a fourth sensor (7)a,Bb,BcAnd BdRespectively processed into X-direction magnetic field reference values B in a signal processing circuitsx、BcxReference value B of magnetic field in Y directionsyAnd BcyThe method comprises the following steps:
the elliptic central magnetic field is recorded as B ═ BM(sinx+siny)，BMThe magnetic induction intensity amplitude of the magnetic field generated by the magnetic steel array is obtained by an elliptical parameter equation, the position coordinates of the four sensors relative to the center of an ellipse are (acos alpha, bsin alpha), (-asin alpha, b)cos alpha), (-acos alpha, -bsin alpha), (asin alpha, -bcos alpha), the sampled magnetic induction signals B of the first sensor (4), the second sensor (5), the third sensor (6) and the fourth sensor (7) are obtained from the periodicity of the magnetic fielda,Bb,BcAnd BdAre respectively as
Figure FDA0002822872780000026
Figure FDA0002822872780000027
Figure FDA0002822872780000028
Figure FDA0002822872780000029
B is to bea,Bb,BcAnd BdIntermediate signal processing is performed to obtain:
Figure FDA00028228727800000210
Figure FDA00028228727800000211
Figure FDA00028228727800000212
Figure FDA0002822872780000031
further obtaining the reference value of the magnetic field in the X direction from (13) to (16)
Figure FDA0002822872780000032
Figure FDA0002822872780000033
Reference value of magnetic field in Y direction
Figure FDA0002822872780000034
Figure FDA0002822872780000035
6. The planar motor mover displacement measurement method of claim 5,
the method for judging whether X-direction displacement is generated or not and whether Y-direction displacement is generated or not is as follows:
if it is
Figure FDA0002822872780000036
If the relative displacement of the planar motor rotor in the X direction is delta X, determining that the planar motor rotor does not generate the relative displacement in the X direction;
if it is
Figure FDA0002822872780000037
If the relative displacement of the planar motor rotor in the Y direction is determined to be delta Y, if the relative displacement of the planar motor rotor in the Y direction is not determined to be delta Y, the planar motor rotor is determined not to generate the relative displacement in the Y direction,
where i represents time.
7. The planar motor mover displacement measurement method of claim 6,
the following method is adopted for judging the positive and negative of the displacement in the X direction and the positive and negative of the displacement in the Y direction:
if B is(i+1)sxBicx-B(i+1)cxBisxIf the displacement in the X direction of the planar motor rotor is greater than or equal to 0, the relative displacement of the planar motor rotor in the X direction is positive, and if the displacement in the X direction of the planar motor rotor is not greater than 0, the relative displacement of the planar motor rotor in the X direction is negative;
if B is(i+1)syBicy-B(i+1)cyBisyAnd if the relative displacement of the planar motor rotor in the Y direction is not positive, the relative displacement of the planar motor rotor in the Y direction is negative.
8. A displacement measuring device for a planar motor rotor is characterized in that the planar motor rotor is sequentially spaced anticlockwise along an oval or round outline
Figure FDA0002822872780000038
-phase arrangement of a first sensor (4), a second sensor (5), a third sensor (6) and a fourth sensor (7), wherein the first sensor is deflected counter-clockwise with respect to the positive X-direction by an initial phase α, wherein if four magnetic induction sensors are distributed along the contour of an ellipse, the two foci of the ellipse are distributed along the X-direction or along the Y-direction, the half axis length in the X-direction is a, the half axis length in the Y-direction is b, if distributed along the contour of a circle, the radius length of the circle is r, r ═ a ═ b, wherein X, Y are orthogonal coordinate axes in the plane of the rotor of the planar motor, the device comprising:
the magnetic field reference value setting module is used for recording phase correlation constants related to an initial phase alpha and an ellipse or circle parameter, and expressing an X-direction magnetic field reference value and a Y-direction magnetic field reference value by using the phase correlation constants;
and the displacement judging module is used for judging whether X-direction displacement is generated or not according to the comparison between the difference value of the X-direction magnetic field reference values at the i +1 moment and the i moment and the X-direction displacement resolution delta X, and judging whether Y-direction displacement is generated or not according to the comparison between the difference value of the Y-direction magnetic field reference values at the i +1 moment and the i moment and the Y-direction displacement resolution delta Y.
9. The planar motor mover displacement measurement device of claim 8, further comprising:
a displacement positive and negative judging module for further judging the positive and negative of the X-direction displacement if the X-direction displacement is generated, and the X-direction counting unit n if the generated X-direction displacement is positiveX＝nX+1, if the X-direction displacement is negative, the X-direction counting unit nX＝nX1, updating the reference value of the magnetic field in the X direction to finish the measurement of the displacement in the X direction, and if the displacement in the X direction is not generated, directly finishing the measurement of the displacement in the X direction;
if Y-direction displacement is generated, the positive and negative of the Y-direction displacement are further judged, and if the generated Y-direction displacement is positive, a Y-direction counting unit nY＝nY+1, if the Y-direction shift is negative, the Y-direction counting unit nY＝nY-1, updating the reference value of the magnetic field in the Y direction to complete the measurement of the displacement in the Y direction, and if no displacement in the Y direction is generated, directly completing the measurement of the displacement in the Y direction,
wherein n isXIs an X-direction counting unit, nYIs a Y-direction counting unit.
10. The planar motor mover displacement measurement device of claim 8,
and the displacement calculation module is used for calculating the relative displacement of the planar motor rotor in the X direction as X-n after the displacement measurement in the X direction and the displacement measurement in the Y direction are both completedXΔ x, and Y-n relative displacement in the Y directionY·Δy。
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