JPS6244225B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the position of a moving body using a loop coil.

BACKGROUND ART For the purpose of controlling moving objects, traffic control, etc., the following position detection method using a loop coil installed on the path of moving objects has been proposed and implemented.

A: An inductance loop method that detects the position of a moving object by using the change in inductance of the loop coil when the moving object moves over the loop coil.

B A level determination method that detects the position of a moving object by transmitting a position signal wave from an antenna installed on the moving object and determining the level of the induced voltage induced in the loop coil.

C. The location of the moving object is determined by feeding a position signal wave to the loop coil, detecting the vertical and horizontal magnetic fields from the loop coil with an antenna installed on the moving object, and determining that the moving object has passed one side of the loop coil. Passage detection method for detection.

However, each of the above three methods has the following drawbacks.

a In the case of the inductance loop method, even if a moving object moves into the loop coil, the change in inductance is small, which poses a problem in terms of detection accuracy.

b In the case of the level discrimination method, coupling to adjacent loop coils becomes a problem. That is, when adjacent loop coils are close to each other, the level difference becomes small, and when the transmitting antenna is located at the end of the loop coil, there is a high possibility of false detection.

c. In the case of the passing detection method, since it detects only passing, it can be used in conjunction with other detection methods, but it is susceptible to noise and the system becomes complicated, such as having to memorize the position at the time of startup.

The present invention solves the various problems mentioned above and proposes a moving body position detection method that can perform position detection satisfactorily, and will be described in detail below with reference to embodiments shown in the drawings.

FIG. 1 shows a layout diagram of a loop coil according to an embodiment of the present invention. In this embodiment, position detection loop coils 1 ₁ to 1 n for configuring each address for position detection are laid at predetermined intervals along the path of the moving body. Further, a phase comparison loop coil 2 is installed to surround each of the position detection loop coils 1 ₁ to 1n. Each of the loop coils 1 ₁ to 1 n and 2 is connected to a processing device 4 using a connecting cable 3 .

Now, in the configuration of such a loop coil, a moving body (not shown) is connected to the loop coil 1 shown in FIG.
₂ , and when a position signal is transmitted from the position signal transmitting antenna 5 installed on this moving body, the loop coil 1 ₂ and the loop coil 2 are connected to the antenna shown in FIG.
As shown in B, in-phase (same phase) signals are induced. On the other hand, since the magnetic flux interlinking with the loop coils _{1 1 and 1 3} adjacent to the loop coil 1 ₂ becomes as _shown in FIG. A signal is induced as in FIG. 3C. In the processing device 4, the loop coil 1
The _phase of the signal induced in the loop coil 2 is compared with the phase of the signal induced in the loop coil 2, and the loop coil (the first In Figure 2, loop coil 1 ₂ ) is detected, and the adjacent loop coil (second
In the figure, position detection data is output only when the signals induced in the loop coils 1 ₁ , 1 ₃ ) are in opposite phase or below the detection level, and the position of the moving body is detected.

If you use a dual system of loop coils and perform position detection by phase comparison, even if a moving object transmits a position signal between adjacent loop coils,
Since in-phase signals are induced in adjacent loop coils, it can be determined that the moving object is outside the loop coils, and erroneous position detection can be avoided.

FIG. 4 shows a block diagram of the processing device 4. The processing device 4 of this embodiment includes a reception selection section 6, a waveform shaping section 7, a phase comparison section 8, a waveform shaping section 9, a position detection control section 10, It is composed of a control device 11. Thus, the signals from the position detection loop coils 1 ₁ to 1n are sequentially switched by the reception selection section 6, waveform-shaped by the waveform shaping section 7, and then applied to the phase comparison section 8. On the other hand, the signal from the phase comparison loop coil 2 is waveform-shaped by the waveform shaping section 9 and then applied to the phase comparison section 8 . The phase comparator 8 compares the phases of the signals from each of the loop coils 1 ₁ to 1 n with the signal from the loop coil 2 . The signal after the phase comparison is processed by a position detection control unit 10 using a microprocessor.
It is output to the control device 11. Switching of the reception selection section 6 is controlled by a signal from the position detection control section 10.

FIG. 5 shows an example of a flowchart of processing in the position detection control unit 10.

Next, when the number of position detection loop coils 1 ₁ to 1n is large and the area of the phase comparison loop coil 2 becomes large, in order to reduce the noise induced in the phase comparison loop coil 2, As shown in FIG. 6, the phase comparison loop coils 2 can also be crossed. In this example, the phase comparison loop coil 2 is crossed every two position detection loop coils, but the crossing interval can be freely selected.

As explained above, in the present invention, a phase comparison loop coil is arranged surrounding a plurality of position detection loop coils, and a signal induced in each position detection loop coil by a signal from a moving object is used for phase comparison. Since the position of the moving body is detected by comparing the phase with the signal induced in the loop coil, it is possible to perform position detection that is resistant to noise and free from false detection. Another advantage is that the system can be easily configured.

[Brief explanation of the drawing]

Fig. 1 is a layout diagram showing the basic configuration of the arrangement of the loop coil in the present invention, Fig. 2 is a sectional view showing the coupling state of the loop coil and antenna in the present invention, and Fig. 3 A, B, and C are Fig. 2 4 is a block diagram showing an example of a processing device according to the present invention, and FIG. 5 is a position detection control section of the device shown in FIG. 4. FIG. 6 is an arrangement diagram showing another example of the arrangement of the loop coil in the present invention. 1 ₁ to 1n...Loop coil for phase detection, 2...Loop coil for phase comparison, 4...Processing device, 5...Antenna.

Claims (1)

[Scope of Claims] 1. A method for detecting the position of a moving body by receiving a signal transmitted from the moving body by one of a plurality of position detection loop coils disposed on the moving path of the moving body. , a phase comparison loop coil is disposed surrounding the plurality of position detection loop coils, and a signal induced in the position detection loop coil and the phase comparison loop coil as the moving body moves; A moving body position detection method characterized in that the position of the moving body is determined by comparing phases. 2. The moving body position detection method according to claim 1, wherein the phase comparison loop coil is provided with a crossover.