JPS625120A - Position detector of moving body - Google Patents

Abstract

PURPOSE:To detect a position of a moving body in an extensive range, by installing a pair of magnetic field detectors for the magnetic fields generated by a lead wire arranged along a travelling guide line on a moving body in inclined positions in the opposite positions. CONSTITUTION:A pair of magnetic field detectors 21, 21 are arranged on an unmanned transporter in inclined positions through an angle of theta in the opposite directions, and cables 11, 12 are installed on the ground at distances W on both sides of a travelling guide line T and the magnetic fields generated by them are detected for obtaining an amount x of the position deviation from the center of the transporter relative to the line T from the amplitude of the signal. In this case, as the center axis of the detector is inclined to the horizontal line, the range available for detection can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a position detection device for a moving object, such as an automatic guided vehicle or an excavator, which is used to move the moving object onto a target line.

[Background of the invention]

In order for a moving object that is not controlled by a human, such as an automated guided vehicle, to travel on a predetermined trajectory, its position is constantly determined, and as soon as it deviates from the trajectory, it is corrected and returned to the predetermined trajectory. Control is required.

For this reason, a position detection device for determining the position of the automatic guided vehicle as described in 5 above should be used. Such a position detection device will be explained with reference to the drawings.

FIG. 4 is a schematic diagram of the configuration of a conventional position detection device. In the figure, 11 and 12 are continuous cables laid along the target line T to guide the automatic guided vehicle, and each cable is placed at a distance W from the target @T. Reference numerals 13 and 14 are magnetic field detectors installed on the automatic guided vehicle (not shown). The magnetic field detectors 13, 14 are composed of receiving coils that generate an induced electromotive force when placed in a magnetic field, and the center axis of this receiving filter coincides with the horizontal direction.

When supplying current to cable 11.12, cable 11
．． 12 generates a magnetic field, and this magnetic field is transmitted to the magnetic field detector 13
．． 14, and a signal corresponding to the detected value button is output. Now, 1: Proportionality constant ω: Angular frequency of the current supplied to the cable If the distance X is -W(x(W), the output e1 of the magnetic field detector 13 and the output e of the magnetic field detector 14
2 is approximately expressed by the following equation.

e, = 1(x+r) sin ωt =-・-・
−(1) e, =, (x−r) sin act
-・-・−・−・(2) Therefore, distance X can be determined by detecting the amplitude of this signal.

FIG. 5 is a block diagram of a calculation device used in the detection device. In the figure, 16.17%! The rectifier 18 is a differential amplifier. The signals e, , e2 are connected to rectifier 1.
6.17, these signals elle! Obtain 9 DC signal stones. These DC signals can be expressed by the following equation.

By inputting one of these DC signal stones to the differential amplifier 18, a signal (BtBz) is obtained. However, E
1=l(,*61.E,=2se2(k2: constant of proportionality).

FIGS. 6(a) and 6(b) are graphs showing the relationship between the distance X and each of the above signals. In each figure, the distance X is plotted on the horizontal axis. FIG. 6(a) shows the output signal el of the rectifier 16.17.
, e, or its amplified signal g1. g2, and when the center position of the automatic guided vehicle coincides with the target line T, that is, when the distance X is 00, the values of both signals become equal. Figure 6 (b
) is a characteristic diagram of the output signal (BIF's) of the differential amplifier 18. Such a characteristic is clear from the characteristic shown in FIG. 6 (a), and the distance X changes linearly within the range of C-r<X<r').

By the way, in such a position detection device, as is clear from the characteristics shown in FIG. 6(b), the distance −r
It is possible to detect the position of the automatic guided vehicle within the range of ``-r, and the position cannot be detected outside the above range. Therefore, if the automatic guided vehicle is small or due to its mechanism, a magnetic field detector If the interval 2'' of 13°14 had to be narrowed, there was a drawback that the position detection range would be limited to a narrow range.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a position detecting device for a moving object that can overcome the drawbacks of the prior art described above and can continuously detect the position over a wide range.

[Summary of the invention]

In order to achieve the above object, the present invention includes a pair of magnetic field detectors that are installed in a moving body and detect magnetic fields generated by conductive wires arranged along a moving target line of the moving body, in opposite directions. It is characterized by being inclined at a predetermined angle.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on the illustrated embodiments.

FIG. 1 is a schematic diagram of a position detection device for an automatic guided vehicle according to an embodiment of the present invention. In the figure, 11.12 is the same cable as shown in Figure 4, T is the moving target line of the automatic guided vehicle, C is the center position of the automatic guided vehicle, and 21.22 is the magnetic field detector installed on the automatic guided vehicle. It is. W is the distance between the moving target line T and the cable 11.12, r is the distance between the center position C of the automatic guided vehicle and the center of the magnetic field detector 21.22, and y is the cable 11
．． 12 and the center of the magnetic field detectors 21 and 22.

While the magnetic field detectors 21 and 22 of this embodiment are provided with the central axis of the coil aligned with the horizontal line in the conventional magnetic field detector, the central axis of the coil is set at an angle θ with respect to the horizontal line. It is installed at an angle. That is, the magnetic field detector 21 has its central axis tilted clockwise by an angle θ with respect to the horizontal line, and the magnetic field detector 22 has its central axis tilted counterclockwise by an angle θ with respect to the horizontal line. . Note that the arithmetic device & that processes the outputs of the magnetic field detectors 21 and 22 is the same as that shown in FIG.

Here, k: proportionality constant The output signal eto of 21 and the output signal e2 of the magnetic field detector 22 can be approximately expressed by the following equations.

e 1゜=k (x0r)+f (θ)e2゜=k(
x-r)f(θ) However, the above formula holds true for each distance W, y, and x.

``When there is a certain relationship, for example, W: y: x: 2 r = 2: 2:
The relationship is 1:1, and the above equation does not necessarily hold true in all cases. However, since the above relationship is within the practical domain, it can be put to practical use unless a special method is adopted.

Figure 2 (at * (bl) is a characteristic diagram of each signal when the detection device shown in Figure 1 is used. In each figure, the horizontal axis shows the distance X. Figure 2 (a) Rectifier 16°17
output signal '10t'2G or its amplified signal E,. ,E
2° characteristic diagram. In the figure, the thin line indicates the inclination angle θ=
0°, that is, the characteristics of the output signal e, , e, of a conventional magnetic field detector. Magnetic field detector 21°220 inclination angle θ = θ
□°, the characteristics of the signal ``self'' move 5&C as indicated by the (-) lateral pressure arrow compared to the characteristics of the signal shoulder, and the characteristics of the signal ``blue'' move to the (+) side as indicated by the arrow compared to the characteristics of the signal 5. Move to.

FIG. 2(b) is a characteristic diagram of the output signal (E, -E2°) of the differential amplifier 18 when the tilt angle θ is set to θ=θ1°. In the figure, the thin line indicates the inclination angle θ=0°, that is, the characteristic of the conventional output signal (E□-Ez).

As is clear from the characteristic diagram shown in FIG. 2(a) K, the range in which the characteristics change linearly is much wider than the conventional range.

As described above, in this embodiment, since the central axes of the coils of the respective magnetic field detectors are provided in the automatic guided vehicle tilted in opposite directions with respect to the horizontal line, the range of detectable positions can be widened. 3 is a schematic diagram of a position detection device for an excavator according to another embodiment of the present invention. In the figure, the same parts as those shown in FIG. 1 are given the same reference numerals.

30 is a small diameter excavator. Such an excavator 30 is used when burying a pipe or the like underground without excavation using a small-diameter excavation method. Since the excavator 30 excavates underground along a predetermined excavation target line TK, it is necessary to detect its position in the example of the rabbit, as in the automatic guided vehicle. Magnetic field detectors 21 and 22 are excavator 3
0, the magnetic field detector 21 is provided with the central axis of its coil tilted clockwise by an angle θ with respect to the horizontal line, and the magnetic field detector 22 is provided with the central axis of its coil tilted counterclockwise with respect to the horizontal line. It is inclined clockwise by an angle θ. The distance X between the excavator 30 and the excavation target line T is detected by the same operation as in the Sagi embodiment. In this case, the only difference from the rabbit embodiment is that the medium of the magnetic field is air or earth, and there is no change in its basic operation.

In this manner, in this embodiment, the central axes of the coils of the magnetic field detectors are mounted on the excavator with their central axes tilted in opposite directions with respect to the horizontal line, so that the range of detectable positions can be widened. To give an example of an experiment, if the distance between the magnetic field detectors is 100 meters, and the depth of the magnetic field detectors from the ground is 3 m, then by summing the inclination angle θ of the magnetic field detectors by 45°, the proportionality of the characteristics can be calculated. The range has been expanded three times compared to before.

In addition, in each of the above embodiments, an automatic guided vehicle and an excavator are illustrated, but it is obvious that the present invention can also be applied to other moving bodies. In addition, in the explanation of the above embodiment, an example was described in which the cables were laid along both sides of the target line. They may be laid apart from each other. As the magnetic field detector, in addition to a coil, a Hall effect type Faraday element, a Josephson effect type, a resonance type magnetometer such as a proton type, a flux gate type, a thin film type, etc. can be used. Furthermore, it goes without saying that the magnetic field detector may be provided on the lower side instead of the upper side.

〔Effect of the invention〕

As described above, in the present invention, since the pair of magnetic field detectors provided on the moving object are mounted with inclinations in opposite directions, it is possible to expand the range in which the position of the moving object can be detected. .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a position detection device for an automatic guided vehicle according to an embodiment of the present invention, FIG. 2 (a+), (b) is a characteristic diagram of the signal of the position detection device shown in FIG. 1, and FIG. A schematic diagram of a position detecting device for an excavator according to another embodiment of the present invention, FIG. 4 is a schematic diagram of a conventional position detecting device, and FIG. 5 is a schematic diagram of a calculation device used in the position detecting device shown in FIG. Block diagram, Figure 6 [a
lt(b) is a characteristic diagram of signals of the arithmetic device shown in FIG. 11.12... Cable, 21.22...
...Magnetic field detector, T...Target line. Agent: Patent attorney Kenjibu Take (and one other person) ζ. Figure 1. ) Figure 2 (b) Figure 3 Figure 4 Figure 5 Distance I Distance I

Claims (1)

[Claims] A position of a moving body including a moving body, a pair of magnetic field detection devices provided on the moving body, a conductive wire disposed along a moving target line of the moving body, and a power source that supplies current to the conductive wire. A position detection device for a moving object, characterized in that the pair of magnetic field detection devices are tilted at a predetermined angle in opposite directions and mounted on the moving object.