JPS6246828B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mobile body position detection method using guided radio.

In the automatic operation of moving objects that travel along a fixed track, such as railway vehicles, various transportation systems, and industrial transport facilities, there are cases where it is necessary to accurately know the position of the moving object at all times. This is a particularly important problem in systems in which a moving object is equipped with an electronic computer and the moving object is automatically driven by a built-in program.

A conventionally known moving body position detection method will be described with reference to FIG.

11 is an intersecting pair of wires having parallel portions 12 and intersecting portions 13 at intervals of P/2, and 14 is a parallel pair of wires, which are laid along the travel path of the moving body. Further, a signal of frequency 1 is supplied to the crossed pair 11, and a signal of frequency 2 is supplied to the parallel pair 14.

On the other hand, the parallel portion 12 of the intersecting pair 11 is attached to the moving object.
Antenna 15a, 1 arranged in the direction of coupling with
5b, an antenna 15c disposed in a direction that couples with the crossing portion 13, and antennas 16a and 16b disposed in a direction that couples with the parallel pair 14. The signal with frequency 1 is sent to antenna 15
a, 15b, 15c, and received by antenna 15c.
A phase shift circuit 17 applies a phase shift difference of 90° to only the signals received at
It is combined with the signal received at 5b and guided to the phase shift comparison circuit 19.

Moreover, the signal of frequency 2 is transmitted through the antennas 16a, 1
6b and guided to the phase comparator circuit 19.

The phase comparison circuit 19 outputs a voltage proportional to the phase shift difference between the output signal from the synthesizer 18 and the signals received by the antennas 16a and 16b, so that the position of the moving object is continuously detected.

However, in this method, since the phase constants of the intersecting pairs 11 and the parallel pairs 14 are different, there is a problem that the detection error increases as the position detection section becomes longer.

Further, since the crossed pair wires 11 and the parallel pair wires 14, which transmit signals of different frequencies, are required, the cost of the entire system increases.

The present invention solves the above-mentioned problems of the prior art, and aims to provide a mobile body position detection system in which the configuration of the guided radio line is simple and there is no detection error.

In the position detection system of the present invention, a guided radio line consisting of two conductors with a repetition period P shifted longitudinally by P/3 is laid along the travel path of the moving object, and one Two antennas arranged in a line at a distance of P/4 in the longitudinal direction of the radio line are mounted on a moving body, and the voltage induced in the antenna by the current flowing through the inductive radio line is in phase with the antenna. It is characterized in that it is decomposed into a voltage and a negative phase voltage, and the position of a moving object is detected based on the phase difference between these two voltages.

An embodiment of the present invention will be described with reference to FIG.

Reference numerals 1a and 1b are conductors constituting the guided radio line, and each conductor 1a and 1b is bent into a waveform with a repetition period P, and is arranged to be shifted by P/3 in the longitudinal direction.

Conductors 1a and 1b are connected from ground transmitter 2 to 50~
High frequency currents I and -I of 200KPH are supplied respectively.

On the other hand, antennas 3a and 3b are arranged in a line in the moving body with an interval of P/4 in the longitudinal direction of the guided radio line.

The Z axis is taken in the longitudinal direction of the guided radio line, and Z is the coordinate of the antenna 3a. By appropriately selecting the separation distance, shape, and dimensions between the antennas 3a, 3b and the guided radio line, the voltage induced in the antennas 3a, 3b can be made sinusoidal with respect to z.

When the voltages induced in antennas 3a and 3b are Va and Vb, respectively, Va=k cos(2π/P)z Vb=k cos(2π/P)(z+P/4) =k cos{(2π/P) z+π/2}
...(1) becomes. k is a constant.

Voltage Va induced in each antenna 3a, 3b,
Vb is the buffer amplifier 4a, 4b, 5a, 5, respectively.
b is converted into an unbalanced voltage.

The outputs of buffer amplifiers 4a and 4b are directly led to adder circuits 9a and 9b, respectively, and buffer amplifiers 5a and 5
The outputs of b undergo phase shifts of -90° and +90° in phase shift circuits 7a and 7b, respectively, and then are led to adder circuits 9a and 9b.

In the adder circuits 9a and 9b, the positive phase voltage Vp and the negative phase voltage Vn are respectively determined by the following calculations.

Vp=Va+Vb e〓 =k cos(2π/P)z +k cos{(2π/P)z+n/2}e=k e〓 Vn=Va+Vb e〓 =k cos(2π/P)z +k cos{2π /P)z+π/2}e=ke= (2) The phase difference between the positive phase voltage Vp and the negative phase voltage Vn is determined by the phase meter 10, and a position signal is obtained. In other words, if the phase difference between Vp and Vn is φ, then φ=∠Vp−∠Vn=(4π/P)Z...(3) (∠: symbol meaning the argument of a complex number), and z is P/ Since φ shows an increase of 2π every time it increases by 2, by measuring φ, the position z of the moving object can be continuously measured at a period of P/2.

In the present invention, the guided radio line consists of two conductors having a repetition period P of P/3 as shown in FIG.
As shown in FIG. 3, two conductors 31a, 3
There are the following advantages over the case of using a simple crossing type guided radio line formed by crossing 1b. When the antenna and the guided radio line are brought close to each other to reduce coupling loss, or when the dimensions of the antenna are restricted by the structural requirements of the mobile object, the voltage induced in the antenna will be reduced as described above. It is no longer a pure sine wave, but contains spatial harmonic components.

Now, if the voltage induced in the antenna 3a by the current I in the conductor 1a in Fig. 2 is Va (+), then It takes the form of

C _2n+1 is the (2m+1)th harmonic content,
This will cause position measurement errors.

Also, due to the current -I of the conductor 1b, the antenna 3a
If the voltage induced in is Va(-), then It takes the form of

Therefore, the total induced voltage Va of the antenna 3a is becomes.

As is clear from equation (6), the 3rd, 9th, 15th, etc.
Harmonic components of integer multiples of are canceled out and do not appear in Va.

The guided radio line as shown in FIG. 3 does not have such a function, which results in errors in position detection.

As explained above, the present invention detects a position using an inductive radio line made of two conductors, and the system is simple and error-free position detection is possible.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional example, FIG. 2 is an explanatory diagram of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of a simple crossing type guided radio line. 1a, 1b...conductor, 3a, 3b...antenna.

Claims (1)

[Claims] 1 Two conductors with repetition period P are P/3
Guided radio lines are laid out along the travel path of the moving object, and two guided radio lines are arranged in a row with an interval of P/4 in the longitudinal direction. An antenna is mounted on a mobile object, and the voltage induced in the antenna by the current flowing through the inductive radio line is decomposed into a positive-sequence voltage and a negative-sequence voltage. A mobile object position detection method characterized by detecting the position of.