JPS58174809A - Azimuth sensor - Google Patents

Abstract

PURPOSE:To obtain the light, compact, and highly accurate sensor, by utilizing dependence of Young's modulus on a static magnetic field in amorphous magnetic alloy. CONSTITUTION:The central part of the thin belt of the amorphous magnetic alloy is fixed, and held so that both ends are freely vibrated. A bias magnetic field is applied to the thin belt 1 of the amorphous magnetic alloy by a DC flowing through a coil 2. The thin belt 1 of the amorphous magnetic alloy 1 is excited in the direction of the magnetic field by an AC. The repeating period of a triangular wave generator 4, which generates a triangular wave at a constant period, is made sufficiently longer than the period of the oscillating output of an oscillator 3. The bias magnetic field is generated in the coil 2 by the DC. The interval between the time when the output of the triangular wave generator 4 is the lowest and the time when the thin belt 1 of the amorphous magnetic alloy is mechanically resonated is measured. Thus the angle between the direction of the mechanical resonation of the thin belt 1 of the amorphous magnetic alloy and the north is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an orientation sensor that uses earth's magnetism to detect the orientation at a certain point.

In recent years, there has been an increasing demand for practical use of devices that can detect orientation with high accuracy, mainly for automobiles. Compasses and needle magnets that utilize geomagnetism have traditionally been used to detect direction. however,
Although a compass has the advantage of being highly accurate, it has the disadvantage of being too large to carry, and a compass has the advantage of being convenient to carry, but it has the disadvantage of poor azimuth accuracy. Therefore, there is a need for an azimuth sensor that is compact and has high azimuth accuracy.

In response to such demands, the present invention aims to provide a light, compact, and highly accurate orientation sensor by using the dependence of Young's modulus on a static magnetic field in an amorphous magnetic alloy. .

FIG. 1 shows an example of the change in Young's modulus in an amorphous magnetic alloy with respect to a static magnetic field. In particular, in iron-based amorphous magnetic alloys, a large change in ring ratio is observed in a certain static magnetic field, as shown between static magnetic fields A and B in the figure.

The difference between the static magnetic fields A and H at this time can be made 10θ or less.

FIG. 2 shows the configuration of an embodiment of the azimuth sensor according to the present invention. In the figure, reference numeral 1 denotes an amorphous magnetic alloy ribbon, which is cut into a rectangular shape from an amorphous magnetic alloy ribbon.The center portion is fixed and both ends are held so as to vibrate freely.

A coil 2 is wound around the amorphous magnetic alloy ribbon 1 so as to form a magnetic core. A bias magnetic field is applied to the amorphous magnetic alloy ribbon 1 by the direct current flowing through the coil 2, and the amorphous magnetic alloy ribbon 1 is excited in the direction of the magnetic field by the alternating current. 3 is an oscillator for flowing alternating current to coil 2;
The frequency is set so that the amorphous magnetic alloy ribbon 1 mechanically resonates at a certain Young's modulus between the static magnetic field B and B in FIG. 4 is a triangular wave generator that generates a triangular wave with a constant period of -. The repetition period of the triangular wave is set to be sufficiently long compared to the period of the oscillation output of the oscillator 3, and a bias magnetic field by DC current is applied to the coil 2. It is something that generates. This bias magnetic field is designed to include the static magnetic fields A and B in FIG. A transformer 5 is used to add the output of the oscillator 3 and the output of the triangular wave generator 4. A resistor 6 is used to detect a change in the current output from the oscillator 3 when the amorphous magnetic alloy ribbon 1 enters a mechanical resonance state. A high input impedance voltmeter 7 is used to detect the voltage between the terminals of the resistor 6. A measuring section 8 detects the lowest output of the triangular wave generator 4, then detects the resonance of the amorphous magnetic alloy ribbon 1 using the voltmeter 7, and measures the time difference.

Reference numeral 9 denotes an output section, which is used to measure the time difference of the measuring section 80 and to correspond to the resonance direction of the amorphous magnetic alloy ribbon 1.

Now, assume that the mechanical resonance direction of the amorphous magnetic alloy ribbon 1 is perpendicular to the earth's magnetism, that is, in the east-west direction. At this time, the oscillation frequency of the oscillator 3 is set so that the amorphous magnetic alloy ribbon 1 resonates with the static magnetic field C shown in FIG. If designed so that...the E-γ-s magnetic field is determined only by the output of the triangular wave generator 4, and the time interval Ti between the lowest value of the triangular wave and the resonance of the amorphous magnetic alloy ribbon 1 is determined by the triangular wave It is expressed by the following equation, with the period of Tt being Tt.

Distribution Ti=−1−=Tt・・・・・・・−・・・・・・・・・(
1) B Next, assume that the mechanical resonance direction of the amorphous magnetic alloy ribbon 1 is oriented in the north-south direction. And the earth's magnetism is the triangular wave generator 4
It is assumed that the direction is the same as the bias magnetic field generated in the coil 2 by vC. At this time, with the oscillation frequency of the oscillator 3 being the same as described above, the amorphous magnetic alloy ribbon 1 in FIG.
If the bias magnetic field from the triangular wave generator 4 is designed to resonate between the static magnetic field and the static magnetic field in FIG. The bias magnetic field of is shifted by DF (-=EG) as shown in FIG. 4, so that it sweeps between the static magnetic field F and 0. Therefore, the time interval T1 between the lowest value of the triangular wave and the resonance of the amorphous magnetic alloy ribbon 1 changes as follows.

Furthermore, it is assumed that the mechanical resonance direction of the amorphous magnetic alloy ribbon 1 is oriented in the north-south direction, and that the earth's magnetism is in the opposite direction to the bias magnetic field generated in the coil 2 by the triangular wave generator 4. At this time, the oscillation frequency of the oscillator 3 is set so that the amorphous magnetic alloy ribbon 1 resonates with the static magnetic field C as shown in FIG. When designed to sweep between the static magnetic field H, the actual bias magnetic field applied to the amorphous magnetic alloy ribbon 1 by the earth's magnetism shifts by +Bx) as shown in Figure 6, and the static magnetic field H, It will now sweep between I. Therefore,
The time interval Ti between the lowest value of the triangular wave and the resonance of the amorphous magnetic alloy ribbon 1 changes as follows.

As mentioned above, in the circuit configured as shown in FIG.
By measuring the interval between the lowest output of the triangular wave generator 4 and the mechanical resonance of the amorphous magnetic alloy ribbon 1, it is possible to determine how many degrees from the north the mechanical resonance direction of the amorphous magnetic alloy ribbon 1 is. The direction is determined.

The orientation detector with this configuration can be applied when only the angle from north is required, that is, when it is not necessary to distinguish between regions 101 and 102 in FIG. 6. However, the direction can also be detected by rotating the mechanical resonance direction of the amorphous magnetic alloy ribbon shown in Figure 2 in a horizontal plane and determining the north and south directions.

FIG. 7 shows the configuration of another embodiment of the orientation sensor of the present invention. In the figure, 11.21 is a rectangular amorphous magnetic alloy ribbon similar to the embodiment shown in FIG.
They are identified such that they form a right angle or a constant angle with each other. 12 and 22 are coils, each amorphous alloy ribbon 1
It is wrapped in 1.21. 13.23 is an oscillator, 1
4.24 is a triangular wave generator having a repetition period longer than the oscillation period of the oscillator 13.23. Reference numerals 15 and 25 designate a waveform summing transformer, 16 and 26 resistors, and 17 and 27 a high input impedance voltmeter for detecting the voltage generated between both terminals.

Reference numerals 18 and 28 are measurement units that measure the time intervals between the lowest output of the triangular wave generators 14 and 24 and the mechanical resonance of the amorphous magnetic alloy ribbon 11.21, and 19 is a time interval measurement unit. This is an output unit that determines the direction based on the information of 18.28 and outputs it.

Each component and its function are similar to the orientation sensor shown in FIG. 2. First, the measuring unit 18,
This can be seen from the output of 28. This is amorphous magnetic alloy ribbon 1
1. At the same time as the information on the mutual positional relationship of 21, the output unit 19
By inputting the amorphous magnetic alloy ribbon 11.12
The direction of can be determined and the orientation detected.

Above, we have described cases in which amorphous magnetic alloy thin strips are attached in one or two directions, but if they are attached in three directions that are not in the same plane, the direction of the earth's magnetic field becomes an inclination angle, and position detection becomes possible. .

As described above, the present invention is an orientation sensor that utilizes the fact that the Young's modulus of an amorphous magnetic alloy changes greatly depending on the static magnetic field. It has extremely excellent features such as being easy to form, mechanically strong, corrosion resistant, can be put to practical use with a small amount of additives to amorphous magnetic alloys, and highly reliable.

[Brief Description of the Drawings] Fig. 1 is a diagram showing the bias static magnetic field dependence of the Young's modulus of an iron-based amorphous magnetic alloy ribbon, and Fig. 2 is a block diagram of an embodiment of the orientation sensor according to the present invention. In this example, Fig. 3 shows the bias static magnetic field amplitude, the bias static magnetic field at mechanical resonance, and the amorphous magnetic alloy ribbon Young's modulus when the amorphous magnetic alloy ribbon is oriented in the east-west direction. Diagram showing the relationship between
The figure shows the bias static magnetic field amplitude and the bias static magnetic field at mechanical resonance and the amorphous magnetic alloy ribbon in this example when the amorphous magnetic alloy ribbon is oriented in the north-south direction and the earth's magnetism is in the same direction as the bias static magnetic field. Figure 6 is a diagram showing the relationship between the Young's modulus of the amorphous magnetic alloy ribbon, and in this example, the amorphous magnetic alloy ribbon is oriented in the north-south direction. Figure 6 is a diagram showing the relationship between the bias static magnetic field and the Young's modulus of an amorphous magnetic alloy ribbon, Figure 6 is a diagram showing two fields in which the orientation cannot be determined according to this embodiment, and Figure 7 is the orientation according to the present invention. FIG. 3 is a block diagram of another embodiment of the sensor. 1.11.21...Amorphous magnetic alloy ribbon, 2°12.22...Coil, 3,13.23...
...Oscillator, 4,14.24...Triangular wave generator, 7,17゜27...High input impedance voltmeter, 8,18゜28...Measurement section ,9,
19...Output section. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4 Nogu Ibuzu Kyoto Kamamai 4 Yame 5 Hiasu Shizuishi Yuki Figure 6 Figure 7. ]7 Figure 2/

Claims (4)

[Claims] (1) It is characterized by having an amorphous magnetic alloy ribbon exhibiting a static magnetic field dependence of Young's modulus, and measuring the orientation by detecting changes in the Young's modulus of the earth's magnetic field of the amorphous magnetic alloy. Orientation sensor. (2) The orientation sensor according to claim 1, wherein a change in Young's modulus of an amorphous magnetic alloy ribbon is detected using its mechanical resonance. (3) The orientation sensor according to claim 1, wherein the amorphous magnetic alloy ribbon is an amorphous magnetic alloy ribbon having magnetostriction. (4) the amorphous magnetic alloy ribbon has a coil wound around it;
2. The orientation sensor according to claim 1, wherein the amorphous magnetic alloy ribbon is excited by applying an alternating current to the coil to measure a mechanical resonance point.