CN102590775A - Method and device for determining orthogonality of dual-axis magnetic sensor by using elliptical vertical intercept method - Google Patents

Abstract

The invention discloses a method and a device for determining the orthogonality of a dual-axis magnetic sensor by using an elliptical vertical intercept method. A nonmagnetic horizontal turntable is arranged on a support shaft. An alignment reference is arranged on one side of the nonmagnetic horizontal turntable. The device for determining the orthogonality of the dual-axis magnetic sensor by using the elliptical vertical intercept method is simple in structure, and comprises the nonmagnetic horizontal turntable serving as a main part. The dual-axis magnetic sensor is arranged on the turntable, and the orthogonality of the dual-axis magnetic sensor can be determined by data acquisition, data fitting and data calculation. The device is easy to use and convenient to operate, has a few measurement error sources, and can be flexibly used, and a few parameters are introduced.

Description

Oval vertical intercept method is measured the method and the device of twin shaft Magnetic Sensor quadrature degree

Technical field

The present invention relates to the Magnetic Sensor technical field, be specifically related to method and device that the vertical intercept method of a kind of ellipse is measured twin shaft Magnetic Sensor quadrature degree.

Background technology

Magnetic Sensor is widely used in industries such as navigation orientation, Aero-Space, geologic prospecting, underground metal pipeline detection.The quadrature degree is the important parameter that influences the Magnetic Sensor precision.

The method of the measurement Magnetic Sensor quadrature degree that the most often uses at present is the magnetic vector sciagraphy, and the principle of this method is comparatively simple---the fundamental operation of vector projection.The angle of x axle for example to be determined and y axle then applies magnetic field B on the x direction of principal axis, the output of measuring the y axle is designated as By, and then the projection theorem according to vector has:

Bcosα＝B _y (1)

The output By of magnetic field B, Magnetic Sensor measures by the instrument and equipment of standard, and the angle that can be tried to achieve Magnetic Sensor by formula (1) is:

$\mathrm{\α}=\arccos \frac{B_y}{B}---\left(2\right)$

The magnetic vector sciagraphy is had relatively high expectations to equipment, needs accurate magnetic field generating apparatus---field coil and supporting high precise current source, and a cover testing apparatus expense is up to units up to a million; Simultaneously, operation steps is complicated, needs to accomplish the axle of Magnetic Sensor and the axle alignment function of field coil, and this is operating as accurate assembly manipulation, and is consuming time longer.

Summary of the invention

To the problem that exists in the prior art, the present invention provides the vertical intercept method of a kind of ellipse to measure the method and apparatus of the quadrature degree of twin shaft Magnetic Sensor, when utilizing the present invention to measure, does not need expensive detection equipment such as field coil, constant current source; Also do not need accurate machinery to debug process, the quadrature degree that only needs a horizontal revolving stage can accomplish Magnetic Sensor is measured, and can reduce the measurement cost, improves efficiency of measurement.

The objective of the invention is to realize like this: the vertical intercept method of a kind of ellipse is measured the method for twin shaft Magnetic Sensor quadrature degree, may further comprise the steps:

1) data acquisition: the Magnetic Sensor level of being placed on to be measured is not had on the magnetic turntable, rotate the data that horizontal revolving stage is gathered Magnetic Sensor;

2) data fitting: the data to gathering are carried out conic fitting, try to achieve the parametric equation of elliptic curve;

3) data computation: ask for two oval vertical intercepts according to elliptic parameter; The substitution formula calculates the quadrature degree of Magnetic Sensor, and formula is:

$\mathrm{\α}=\arcsin \left(\frac{T}{S}\right)=\arcsin \left(\frac{y_M-y_N}{y_P-y_Q}\right)---\left(13\right)$

Wherein, T, S represent the length value of the characteristic line segment in the oval characteristic parameter, and promptly vertical intercept is through trying to achieve the ordinate y of 4 P on the fitted ellipse, Q, M, N _P, y _Q, y _M, y _NCan try to achieve orthogonal angles α.

The vertical intercept method of a kind of ellipse is measured the device of twin shaft Magnetic Sensor quadrature degree, and no magnetic horizontal revolving stage is installed on the back shaft, and no magnetic horizontal revolving stage one side is provided with alignment fiducials.

The vertical intercept method of ellipse provided by the invention is measured the method and the device of twin shaft Magnetic Sensor quadrature degree, does not need expensive detection equipment such as field coil, constant current source; Also do not need accurate machinery to debug process, the quadrature degree that only needs a horizontal revolving stage can accomplish Magnetic Sensor is measured.The level that only has as major equipment does not have the magnetic turntable, the twin shaft Magnetic Sensor is placed on turntable can measures twin shaft Magnetic Sensor quadrature degree, uses simply, and the parameter of introducing is few, and sources of measurement error is few, and is easy to operate, uses flexibly.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is described further.

Fig. 1 is the synoptic diagram of magnetic vector sciagraphy, and wherein B represents externally-applied magnetic field.

Fig. 2 is that difference differs corresponding lissajous figures.

Fig. 3 is oval characteristic parameter.

Fig. 4 is the apparatus structure synoptic diagram that oval vertical intercept method is measured twin shaft Magnetic Sensor quadrature degree.

Embodiment

The present invention provides the structure of the device that phase difference method measures twin shaft Magnetic Sensor quadrature degree as shown in Figure 4: a kind of phase difference method is measured the device of twin shaft Magnetic Sensor quadrature degree; No magnetic horizontal revolving stage 1 is installed on the back shaft 2, and no magnetic horizontal revolving stage 1 one sides are provided with alignment fiducials 3.The effect of alignment fiducials 3 is to aim at handled easily and record for the scale of not having magnetic horizontal revolving stage 1.

The measuring method that the present invention adopts is following: utilize the terrestrial magnetic field as natural normative reference; Magnetic Sensor 4 to be measured is placed on the no magnetic horizontal revolving stage 1; Rotate no magnetic horizontal revolving stage 1 and obtain required measurement data combination; Carry out the parametric equation that conic fitting is tried to achieve elliptic curve then, and then using formula is tried to achieve the quadrature degree of Magnetic Sensor.

Oval vertical intercept method measuring principle is following:

Can know that according to the ultimate principle in the electronic surveying (the sinusoidal signal composograph of two same frequencys is for oval) Magnetic Sensor rotates a week under the environment of terrestrial magnetic field, the figure that its diaxon output is constituted is for oval.

French scientist Jules Lissajous1875 characterizes the synthetic output of two single frequency sinusoidal signals like (Lissajous) figure with Li Sa in the paper that Paris, FRA academy of sciences delivers. and when the frequency of two signals was identical, lissajous figures was oval.Be provided with two sinusoidal signals, its amplitude is respectively A _x, A _y, angular frequency is ω, and initial phase angle is respectively

Its mathematic(al) representation is suc as formula (3):

It is horizontal ordinate with the X in the formula (3) that definition differs

; Y is an ordinate; Draw out the lissajous figures that difference differs, like Fig. 2.

Can be found out intuitively by lissajous figures: the extreme value of oval inclined degree and long and short axle has been represented sinusoidal characteristic element respectively.

The parameter of elliptic curve can be tried to achieve with least square method.If the measuring point coordinate is (x _i, y _i), wherein i=1～n then can make up system of equations, as follows:

Ax _i ²+Bx _iy _i+Cy _i ²+Dx _i+Ey _i+F＝0(4)

I=1～n wherein, n >=5

It is following that above-mentioned system of linear equations is write as matrix form:

$\left[\begin{array}{cccccc}{x_1}^2& x_1{y}_1& {y_1}^2& x_1& y_1& 1\\ {x_2}^2& x_2{y}_2& {y_2}^2& x_2& y_2& 1\\ ...& ...& ...& ...& ...& ...\\ {x_n}^2& x_n{y}_n& {y_n}^2& x_n& y_n& 1\end{array}\right]\left[\begin{array}{c}A\\ B\\ C\\ D\\ E\\ F\end{array}\right]=0---\left(5\right)$

Order:

$F=\left[\begin{array}{cccccc}{x_1}^2& x_1{y}_1& {y_1}^2& x_1& y_1& 1\\ {x_2}^2& x_2{y}_2& {y_2}^2& x_2& y_2& 1\\ ...& ...& ...& ...& ...& ...\\ {x_n}^2& x_n{y}_n& {y_n}^2& x_n& y_{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="120106201326.png"\; state="\{\{state\}\}">n</figure-callout>}}& 1\end{array}\right],$

M＝(A，B，C，D，E，F) ^T

Then system of equations can be write as:

FM＝0(6)

When measuring point was counted n=5, system of linear equations was by unique solution.

When measuring point was counted n＞5, equation (6) was an inconsistent equation, does not accurately separate, but least square solution is arranged, and generally finds the solution with least square method.The least square solution of equation this moment (6) is:

E＝(FM) ^T(FM)＝min(7)

By Can solve M=(a, b, c, d, e, f) ^T, also can obtain the equation of elliptic curve:

ax ²+bxy+cy ²+dx+ey+f＝0(8)

Oval center is by confirming the zero point of Magnetic Sensor.Extreme point P (the x of the ordinate of point on the ellipse _P, y _P), Q (x _Q, y _Q) can confirm have by formula (3) at the extreme point place of sine function:

$\left\{\begin{array}{c}{y}_P=A_y+X_0\\ y_Q=-A_y+Y_0\end{array}\right.---\left(9\right)$

The length of note line segment PQ is S, then can be got by formula (9):

S＝y _P-y _Q＝2A _y (10)

The phase place of x axle is 0 value in the modus ponens (3), and promptly

then has this moment:

$\left\{\begin{array}{c}x=X_0\\ y=\&PlusMinus;A_y\sin \mathrm{\&alpha;}+Y_0\end{array}\right.---\left(11\right)$

Formula (11) is corresponding to horizontal ordinate x=X among Fig. 3 ₀Point, that is M (x _M, y _M), N (x _N, y _N) 2 points.The length of note Fig. 4 middle conductor MN is T, can be got by formula (11):

T＝y _M-y _N＝2A _ysinα(12)

Simultaneous formula (10), formula (12) two formulas can obtain:

$\mathrm{\&alpha;}=\arcsin \left(\frac{T}{S}\right)=\arcsin \left(\frac{y_M-y_N}{y_P-y_Q}\right)---\left(13\right)$

Can know by formula (13), only need try to achieve line segment length S, the T value among Fig. 3, as long as that is can try to achieve the ordinate y of 4 of P on the fitted ellipse, Q, M, N _P, y _Q, y _M, y _N, then the angle of Magnetic Sensor can be tried to achieve by formula (13).

Because line segment length S, T representative all is intercepts of ordinate, so called after ordinate intercept method.

Because of 4 of P, Q, M, N all on elliptic curve, so its coordinate satisfies the equation of elliptic curve, can obtain:

ax _P ²+bx _Py _P+cy _P ²+dx _P+ey _P+f＝0(14)

ax _Q ²+bx _Qy _Q+cy _Q ²+dx _Q+ey _Q+f＝0(15)

ax _M ²+bx _My _M+cy _M ²+dx _M+ey _M+f＝0(16)

ax _N ²+bx _Ny _N+cy _N ²+dx _N+ey _N+f＝0(17)

Simultaneous formula (14)～(17) can obtain:

$S=\frac{4\sqrt{a^2{e}^2-\mathrm{abed}-4a^2\mathrm{cf}+\mathrm{<figure-callout\; id="2"\; label="ac\; d"\; filenames="120106201326.png"\; state="\{\{state\}\}">ac</figure-callout>}{d}^{}{}^2+a{b}^2\mathrm{<figure-callout\; id="4"\; label="f"\; filenames="120106201326.png"\; state="\{\{state\}\}">f</figure-callout>}}}{4\mathrm{ac}-b^2}---\left(18\right)$

$T=\frac{2\sqrt{{4a}^2{c}^2{e}^2-4\mathrm{<figure-callout\; id="2"\; label="ab\; c"\; filenames="120106201326.png"\; state="\{\{state\}\}">ab</figure-callout>}{c}^{}{}^2\mathrm{de}-a^2{b}^2{c}^2-a{b}^2\mathrm{<figure-callout\; id="2"\; label="c\; e"\; filenames="120106201326.png"\; state="\{\{state\}\}">c</figure-callout>}{e}^{}{}^2+4a{d}^2{c}^3-16a^2{c}^{3}f+{\mathrm{<figure-callout\; id="3"\; label="b"\; filenames="120106201326.png"\; state="\{\{state\}\}">b</figure-callout>}}^3\mathrm{cde}+8a{b}^2{c}^{2}f-{\mathrm{<figure-callout\; id="4"\; label="b"\; filenames="120106201326.png"\; state="\{\{state\}\}">b</figure-callout>}}^4\mathrm{cf}}}{c(4\mathrm{ac}-b^2)}---\left(19\right)$

With value substitution to the formula (13) of S, T, can try to achieve the quadrature degree of Magnetic Sensor.

The actual measurement example:

For verifying the measurement result of the method that this patent proposes, chosen a Magnetic Sensor and measured.The actual output that records Magnetic Sensor is as shown in the table.

The output of Magnetic Sensor X axle	The output of Magnetic Sensor Y axle
		?-11656	1088
?-9513	7239
		?-4711	11557
?1512	12962
		?7435	11090
?11444	6385
		?12503	96
?10349	-6046
		?5534	-10383
?-673	-11778
		?-6584	-9907
?-10605	-5192
		?-11663	1078

The utilization least square, the parameter that can try to achieve ellipse is:

a	6.81857E-09
		b	-6.8073E-10
c	6.54094E-09
		d	-5.36245E-06
e	-7.47578E-06
		f	-1

With above-mentioned 6 parameter substitution to quadrature degree formula (13), can try to achieve the quadrature degree of Magnetic Sensor:

The above results is compared with the measurement result (87.1 °) of magnetic vector sciagraphy, can know: because the equipment that uses is less, the error source that the method for this patent is introduced is less, so can obtain higher measuring accuracy.

Method provided by the invention also can be measured respectively three sensitive axes of magnetic sensor in twos, thereby the quadrature degree that carries out magnetic sensor is measured.

Phase difference method provided by the invention is measured the method for Magnetic Sensor quadrature degree, and the measured Magnetic Sensor that is not limited to a certain type can be a fluxgate type, can be reluctance type, also can be the Magnetic Sensor of other any kinds.

Claims (2)

1. an ellipse is indulged the method that intercept method is measured twin shaft Magnetic Sensor quadrature degree, it is characterized in that: may further comprise the steps:

1) data acquisition: the Magnetic Sensor level of being placed on to be measured is not had on the magnetic turntable, rotate the data that horizontal revolving stage is gathered Magnetic Sensor;

2) data fitting: the data to gathering are carried out conic fitting, try to achieve the parametric equation of elliptic curve;

3) data computation: ask for two oval vertical intercepts according to elliptic parameter; The substitution formula calculates the quadrature degree of Magnetic Sensor, and formula is:

$\mathrm{\&alpha;}=\arcsin \left(\frac{T}{S}\right)=\arcsin \left(\frac{y_M-y_N}{y_P-y_Q}\right)---\left(13\right)$

Wherein, T, S represent the length value of the characteristic line segment in the oval characteristic parameter, and promptly vertical intercept is through trying to achieve the ordinate y of 4 P on the fitted ellipse, Q, M, N _P, y _Q, y _M, y _NCan try to achieve orthogonal angles α.

2. an ellipse is indulged the device that intercept method is measured twin shaft Magnetic Sensor quadrature degree, and it is characterized in that: no magnetic horizontal revolving stage (1) is installed on the back shaft (2), and no magnetic horizontal revolving stage (1) one side is provided with alignment fiducials (3).

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