JPH0229993B2 - JIKAIBEKUTORUKENSHUTSUSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic field vector detection device used to accurately detect components in each direction of a magnetic field vector or to accurately match the detection directions of a plurality of similar detection devices. It is.

Conventionally, in this type of device, when fluxgate type magnetic field detectors are arranged as orthogonal pairs, the orthogonality and horizontality of each coil, and the direction of each pair of coils when multiple pairs of detectors are used. A precise fine-adjustment mechanism is required in order to match the values, and this has the disadvantage of making it large and expensive. On the other hand, as a device for electrically adjusting the magnetic axis of a magnetic detector, two magnetic detecting elements for adjusting the magnetic axis are attached to the magnetic detector and are perpendicular to each other, and the output of the magnetic detecting elements is connected to the output of the magnetic detector. By adding it, the magnetic axis of the magnetic detector is apparently adjusted, and the main magnetic sensing element is connected so as to add the outputs of the two magnetic sensing elements for direction adjustment, and the direction of the main magnetic sensing element is adjusted. A magnetic axis adjustment device for a magnetic detector has been proposed that corrects the .

However, in such a device, the addition is simply done on the wiring via an output regulator, and the three magnetic sensing elements, the main magnetic sensing element and the first and second axial adjustment magnetic sensing elements, are integrated. There was a problem in that it only had the ability to detect magnetic fields in one direction, and only one output appeared on the detection element connection.

The present invention has been made in view of the above circumstances, and its purpose is to electrically correct mechanical dimension and angular errors included in each component output of a vector detector with an extremely simple configuration, and to improve reliability. It is an object of the present invention to provide a compact and inexpensive magnetic field vector detection device.

In order to achieve such an objective, the present invention
For each of the plurality of vector detectors constituting the magnetic field vector detection device, an amplifier that inputs the output of the vector detector through an amplitude adjustment impedance element and an inverting amplifier that uses the output as an inverting input are provided, Moreover, the output from the phase adjustment impedance element connected between the inverting input terminal and the output terminal of the inverting amplifier is connected to be added and input to the above-mentioned amplifier, which receives the output of the other orthogonal vector detector. Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Figures 1 and 2 are diagrams for explaining the principle of the present invention; Figure 1 shows the case without angular error, and Figure 2 shows the case with angular error. It is. In the figure, 1 is an x detector that detects the component of the magnetic field vector Consists of output winding. Here, to explain this fluxgate type magnetometer, the magnetic core used in it is excited by a continuous wave current or voltage waveform of a sinusoidal or rectangular waveform until the magnetic core is sufficiently saturated. When a magnetic field is applied, a distorted output voltage containing even harmonic components of the excitation frequency corresponding to the strength of the magnetic field is induced in the output winding of the magnetic core. By extracting the second harmonic component from this waveform using various methods, it is possible to measure the strength of the external magnetic field, and it is also called the double frequency waveform magnetic modulation method. In addition to this fluxgate magnetometer, the principles of the present invention can be applied in exactly the same way to other magnetometers. The principle of the present invention will be explained below with reference to FIGS. 1 and 2.

Now, let the magnetic field vector be H=Hx+Hy+Hz,
When measuring the horizontal component Hxy=Hx+Hy, if the orthogonality of the x and y detectors 1 and 2 is maintained and the detectors are placed horizontally, as shown in FIG.
The outputs hx and hy of the x and y detectors 1 and 2 are as follows: hx = K ₁ Hxycos = K ₁ Hx = KHx (1) hy = K ₂ Hxysin = K ₂ Hy = KHy (2). Note that K ₁ and K ₂ are constants, and the gains of both the x and y detectors 1 and 2 are adjusted so that K ₁ =K ₂ =K.

Next, as shown in FIG. 2, when the x-detector 1 is placed deviated from the above state by an angle δx,
The output hx' of the x detector 1 is hx'=KHxy cos(+δx)=K ₁ Hxy(cos cos δx−sinsin δx) (3).

When the angle δx is sufficiently small, the above equation (3) can be approximated by hx'=KHxy(cos-δxsin)=K(Hx-δxHy)=hx-δxhy (4). Similarly, when the y detector 2 is placed shifted by an angle δy, the output hy' of the y detector 2 becomes hy'≈K(Hy+δyHx)=hy+δyhx (5). From equations (4) and (5) above, the outputs hx' and hy' of x and y detectors 1 and 2 are hx' = hx - δx (hy' - δyhx) = hx - δxy' + δxδyhx ...(6) It is expressed as hy′=hy+δy(hx′+δxhy)=hy+δyhx′+δxδyhy…(7). Since the angular deviations δx and δy are sufficiently small, the third item on the right side of equations (6) and (7) is zero (0).
Therefore, the output values hx and hy when there is no deviation from the outputs hx' and hy' of x and y detectors 1 and 2, which have angular deviations of δx and δy, can be calculated using the following equations (8) and (9).
It can be found from

hx＝hx′＋δxhy′…(8) hy＝hy′−δyhx′…(9) Similarly, the vertical axis of the detector is
Detector output when the axis is tilted by α and β respectively
hx′ and hy′ are expressed as hx′=KHxy, coscosα+K3Hzsinαcosβ =hxcosα+hzsinαcosβ…(10) hy′=KHxy, sincosβ+K ₃ Hzcosαsinβ =hycosβ+hzcosαsinβ…(11). However, K ₃ is a constant and K ₃ Hz=hz.

When α and β are small, the above equations (10) and (11) become hx′≒hx＋αhz …(12) hy′≒hy＋βhz …(13) The values hx and hy when there is no are calculated using the following formula.

hx=hx'-αhz (14) hy=hy'-βhz (15) Such a corrected output can be obtained with the following circuit configuration. First, the basic method will be explained using FIG. In the same figure, 3,
4 is a repeating amplifier for the y-detector output hy' and the z-detector output hz', which has variable resistors 6 and 7, and thereby calculates values corresponding to the angular deviations of δx and α in (8) and (14) above. is adjustable. That is, an output with the phase of the input inverted is obtained at the output terminal of the inverting amplifier 3, but since the variable resistor 6 is connected between this output terminal and the input terminal, from this variable resistor 6 (8) It is possible to obtain a corrected output corresponding to the second term on the right side of the equation. For example, the left end of the variable resistor 6 (close to the input terminal of the inverting amplifier 3) provides the y detector output hy', but the right end (close to the output terminal of the inverting amplifier 3) provides an output with the opposite phase to hy'. In other words-
Ahy' (A is a positive coefficient) is obtained, and by setting conditions appropriately, it is possible to obtain δxhy'. Similarly, from the variable resistor 7, a correction output −αh′z (hz′=hz) corresponding to the second term on the right side of equation (14) is obtained,
By inputting these together with h'z to the summing amplifier 5, mechanical errors in the x-detector output are electrically corrected and an accurate x-detector output xout is obtained.

Although the y-detector output can be corrected in exactly the same way, in the present invention, these corrections are not performed in independent circuit configurations, but are mutually corrected to simplify the circuit.

FIG. 4 is a configuration diagram showing an embodiment of the present invention.
This shows an example where hz can be considered to be a constant value (when not moved over a wide range). In Fig. 4, the same numbers as in Figs. 1, 2, and 3 indicate corresponding parts, 3' is an x-inverting amplifier, 5' is an adder circuit, and 6' and 7' are variables for error correction. Resistor,
8 and 9 are variable resistors for gain adjustment.

Next, the operation of the embodiment shown in FIG. 4 will be explained. First, the inverting amplifiers 3 and 3' have variable resistors 6 and 6', respectively, and the adder circuits 5 and 5' have x detector output hx' and y detector output hy', respectively, and variable resistors 6 and 6. The output from ' and the reference voltage set by variable resistors 7 and 7' are input, and the two are compared to perform addition correction. The outputs of the adder circuits 5 and 5' obtained in this way are sent out via the x-inverting amplifier 3' and the y-inverting amplifier 3, respectively, and the x output x out and the y output y out each have an angular error with respect to the z direction. It is possible to obtain the x and y outputs when it can be considered constant.

In this way, the mechanical dimension and angular errors included in the output of each component of the vector detector can be electrically corrected.

In reality, it is common to use multiple detection devices consisting of such x and y detectors and average the measurement results obtained from each device to obtain the true value. In such a case, the above-mentioned x, y like
Mutual correction of detector outputs is not limited to one detection device, but may be performed between other detection devices arranged vertically or horizontally apart, and these multiple detection devices are configured. It can also be used to align the detection directions of each detector.

As explained above, according to the present invention, the detector outputs of each direction component can be mutually corrected by simply adding a simple circuit configuration without using a special detector for correction. Accurate magnetic field measurements can be performed.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining the principle of the present invention, FIG. 3 is a circuit diagram for explaining the output correction method in the magnetic field vector detection device according to the present invention, and FIG. FIG. 2 is a circuit diagram showing an example. 1...x detector, 2...y detector, 3, 3', 4...
Inverting amplifier, 5, 5'...addition circuit, 6, 6', 7,
7'...variable resistor for error correction.

Claims (1)

[Claims] 1. In a magnetic field vector detection device that has a plurality of vector detectors and detects components in each direction of a magnetic field vector, the output of the vector detector is input to each vector detector via an impedance element for amplitude adjustment. A first amplifier and a second amplifier each having the output of the first amplifier as an inverting input and an impedance element for phase adjustment connected between the inverting input terminal and the output terminal, and A magnetic field vector detection device characterized in that the output from the phase adjustment impedance element of the amplifier is connected to be added and input to a first amplifier which inputs the output of the vector detector in the other direction orthogonal to each other.